DK161520B - ANALOGY PROCEDURE FOR THE PREPARATION OF PENEME DERIVATIVES AND INTERMEDIATES FOR USE BY THE PROCEDURE - Google Patents

Description

in

DK 161520B

The present invention relates to an analogous process for the preparation of novel 2-substituted and 2,6-disubstituted penem compounds which possess potent antibiotic activity.

The invention further relates to novel intermediates which are valuable for the preparation of the biologically active penne derivatives. The pen embryo system has the formula 4 6 5 5 sv - \ l 10 J - O 7 1 \ 2 and can be systematically referred to as 7-oxo-4-thia-1-azabicyclo [3,2,0] -15 hept-2-ene. For the sake of simplicity, this is referred to as "2-penem" and the following numbering system is used: in 20 - 1 \ 2_ ίκ 25

Thus, according to the present invention, there are provided novel 2,6-disubstituted penes of the formula 30 Y \ - r "\ 1_I y- (Alk) -A- (Alk ') - NH2 O \ co2z

35 I

and pharmaceutically useful salts thereof, wherein Alk is C 1-6 alkylene, A is 0, S or SO, Alk 'is C 2

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2 Y is hydrogen or lower alkyl, which may be substituted by hydroxy, by an analogue and process which is characterized by the characterizing part of claim 1.

The compounds of formula I and pharmaceutically acceptable salts thereof 5 are potent anti-bacterial agents.

From DE-A-2819655, related penem compounds are known which exhibit antibacterial activity or which can be used as intermediates in the preparation thereof. However, the compounds of formula (I) of the present invention, when comparing the biological data set forth below and the activity set forth in DE-A-2819655 on pages 38-39, exhibit a surprisingly broader spectrum of activity.

Since the 2-substituted compounds of formula I contain an asymmetric carbon atom, these compounds may exist either in the form of racemic mixtures (R, S form) or as the individual dextrorotatory and 1evorotatory (R and S forms) optical isomers.

The preferred compounds are those in which the configuration of the 5-carbon atom corresponds to the configuration in natural penicillin (5R configuration). Substituents at the 5- and 6-positions of the 2,6-disubstituted penem compounds may be in cis or trans position relative to each other. When the penem compound 6 substituent contains an asymmetric carbon atom, the resulting isomers are here identified as isomers A, B, C and D (see Example 5 with respect to the stereochemistry). The preferred isomer in compounds of this type is isomer B. Separation of the various optical and geometric isomers can be carried out by conventional separation and cleavage methods well known to those skilled in the art.

The present invention is intended to encompass the compounds of formula I in the form of both isomeric mixtures and in the form of the individual separated and cleaved isomers.

The pharmaceutically acceptable salts mentioned above comprise the non-toxic carboxylic acid salts, e.g. non-toxic metal salts such as the sodium, potassium, calcium, aluminum and magnesium salts, the ammonium salt and the salts with non-toxic amines such as trialkyl amines (triethylamine), procaine, dibenzylamine, N-benzyl phenethylamine, 1-ephen-35 amine, N, Ν'-dibenzyl ethylenediamine, N-alkylpiperidine and other amines which have been used to form salts of pencillins and cephalosporins. When a basic group is present, the invention also includes the pharmaceutically acceptable acid addition salts, e.g. salty with

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3 mineral acids such as hydrochloric acid, hydrobromic acid, hydrogen iodide acid, phosphoric acid, sulfuric acid, or with suitable organic carboxylic acids or sulfonic acids such as trifluoroacetic acid, p-toluenesulfonic acid, maleic acid, acetic acid, citric acid, oxalic acid, succinic acid, benzoic acid, fumaric acid, mandelic acid, ascorbic acid and malic acid. Compounds containing an acidic group and a basic group may also be in the form of internal salts, namely, zwitterions. Preparation of the salts described above can be carried out according to conventional methods for forming salts of / Mactam antibiotics such as penicillins and cephalosporins.

The term "readily cleavable ester protecting group" is a term which has been given a specific meaning within the β-lactam and peptide chemistry.

Many such groups are known which are used to protect the carboxyl group during subsequent chemical reactions and which can later be removed by standard methods to form the free carboxylic acid. Known ester protecting groups include 2,2,2-trichloroethyl, tertiary alkyl having from 4 to 6 carbon atoms, tertiary alkenyl having from 5 to 7 carbon atoms, tertiary alkynyl having from 5 to 7 carbon atoms, alkoxymethyl, alkanoylmethyl having from 2 to 7 carbon atoms, N-phthalimidomethyl, benzoylmethyl, halo-benzoylmethyl, benzyl, p-nitrobenzyl, o-nitrobenzyl, benzhydryl, trityl, trimethylsilyl, triethyl silyl, o-trimethylsilylethyl, and the like. The choice of an ester protecting group depends on the subsequent reaction conditions that the group must be able to withstand and the desired conditions for removal thereof. The selection of a suitable group clearly falls within the skill of the artisan. For use as a chemical intermediate, the most preferred ester is the p-nitrobenzyl ester, which can be easily removed by catalytic hydrogenation.

For the preparation of compounds containing functional groups which can be reduced under such removal conditions, a preferred alternative is the β-trimethylsilylethyl ester which can be removed by treatment with fluoride ions. Furthermore, within the framework of easily removable ester protecting groups, physiologically cleavable esters fall, i. such esters which from the penicillin and cephalosporin range are known to be readily cleaved in the body to the stem acid. Examples of such physiologically cleavable esters include indanyl, phthalidyl, methoxymethyl, glycyloxymethyl, phenylgiycyloxymethyl, thienylglycyloxymethyl or acyloxymethyl of the formula

DK 161520B

4 -CH2CC = O) -Y 'wherein Y' represents C1-C4 alkyl or phenyl. Particularly preferred esters of this type are methoxymethyl, acetoxymethyl, pivaloyloxymethyl, phthalidyl and indanyl.

As will be appreciated, the compounds of formula I may exist in various solvation stages and both the anhydrous and the solvated forms (including hydrates) fall within the scope of the invention.

The compounds of formula I prepared by the process according to the invention are those wherein Y represents hydrogen or (lower) alkyl optionally substituted (preferably at the α-carbon atom) by hydroxy. In particular, the process of the invention prepares compounds within the above group wherein Y represents 15 hydroxy, ethyl or α-hydroxyethyl. Specifically, in the process of the invention, such compounds of formula I are prepared wherein Y represents hydrogen or α-hydroxyethyl. More particularly, in the process of the invention, such compounds are prepared wherein Y represents α-hydraxymethyl.

In accordance with a preferred embodiment of the process of the present invention, compounds of formula I are prepared in which the 2-substituent is - (Alk) -O- (Alk ') 25 in which Alk and Alk7 have the above meanings.

In accordance with a further preferred embodiment of the process of the present invention, compounds of formula I are prepared wherein the 2-substituent is 30 - (Alk) -S- (Alk ') - NH 2 wherein Alk and Alk7 are as defined above.

In a particularly preferred embodiment of the process of the present invention, the following compounds of formula I are prepared: (a) Y = H; 2-CH20CH2CH2NH2; (b) Y = α-hydroxyethyl; 2-CH20CH2CH2NH2;

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(C) Y = H; 2-CH2SCH2CH2NH2; (d) Y = α-hydroxyethyl; 2-CH2SCH2CH2NH2; 0 (e) Y = H; 2-CH2ScH2CH2NH2; and (f) Y = α-hydroxyethyl; 2-CH2SCH2CH2NH2;

The most preferred compounds of the invention are those wherein Y = hydrogen, or more preferably α-hydroxyethyl, and the 2-substituent is -CH 2 OCH 2 CH 2 NH 2. In a further aspect, the present invention comprises novel intermediates of the formula:

Q

15 y _. S -C- (AU-) -A- (AUc) -N3

T "T

0> -N \ p (Q) 3 co2r "

II

wherein Y is as defined above with respect to compounds of formula I, Q is phenyl or (lower) alkyl, R "is an easily removable ester protecting group.

In the intermediates of formula II, Q preferably represents phenyl, R "preferably p-nitrobenzyl, and Y preferably the substituent groups listed as preferred for the compounds of formula I. Reactive functional groups such as mercapto, amino and hydroxy in the substituent Y can be protected by conventional blocking groups during the conversion of the intermediates into biologically active end products.

Compound I can be prepared by one or more of the reaction pathways mentioned below. The various synthetic pathways can be divided into three main processes depending on the step in which the 6-substituent, namely Y, is incorporated. According to method I, the 6-substituent is incorporated into the starting material itself, according to method II, Y is incorporated at the end of the synthesis and according to method III the substituent Y is introduced midway into the synthesis. Each of the three main

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6 processes can again be varied by the method used to introduce the desired 2-substituent. In general, it is preferred to introduce the substituent Y midway into the synthesis and introduce the 2-substituent by acylation of the mercaptide intermediate III or III shown below, since these methods have been found to be the most widely applicable.

The various steps of Process I are shown in the following reaction scheme:

Method I (variant 1): Early introduction of 2-substituent 7

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Y il N- ^ 0Ac xc-SNa 5 Y-CH = CH-OAc _CSI> I - ^ ΓΓΓ ^ o X η 0 9

Il V I

ϊ-> ~ _sc-x _> V_ ^ SC-X -> CHO SOC12 yf-N PQ Ό »X? - CT C02R 0 ^^ C02R"

? \ Y II

Y \ _ ^ sc-x on Δ ^ I -I -> / -N Cl base J-N \ ^ P03 O 0 [C02R "co2r"

Y c Y

rø-x - * free S? N '/ deprotection

° C02R "° C02H

island

II

AC = CH3C- = C6h5-X = The desired 2-substituent

Method I (variant 2): Late introduction of the 2-substituent-8

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Y?

X S ΠΆc II

1CH-C-SNa Y-CH = CH-OAc CSIv I 3 \ * PH 7.5 "

o XH

Y _____ p - SAc _ ^ Y-U _ ^ SAc _ CHO soci2

sZS N PQ pli S, -N>. , OH

O XH C02R V - co2r "

Y \ rSAc ON Υ'Λ "'- | τ' SAC MA

I u I Γ—> J _C1 base J N base o y 3 C02Rm co2r "o Y ^ _ O y II.

χ-j. φ Y - ^ _. SC-X A ^ QJ —'N \ ^ P03 CO ^ R "C02R" Y-v. Fri_> vrv

^^ deprotection 1 -H

° CO R "O \ 2 CO 2 H X_c (= 0) .- 0 = acylating agent {, 5¾ = heavy metal salt

Method I (variant 3): Late introduction of 2-substituent 9

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Y \ - ^ OAc 0 CSNa Y-CH = CH-OAc CSI ^ __Z -> ->

o ^ H

-r ^ SCØ ^ _Y * S-r-'SC03 -7 * | GHO I SOCl2 0 ^ “N \ έ ° 2κ" C02R "^ _J-SC03 p03 Y> ^ - J-SC03 .MA_ ^ i-N- ^ r-C1 base ^" J-baSe "" o 0 CO2R "co2r "o

v O v II

"η — pSM x-c- e ^" p — f sc "x &.

0 ^ -N \ ^ po 3 * 0J-n ^ po 3 CO 2 R ", co 2 R"

V .S Y

^ rfy 's ~~~ (deprotection _-N f / ° CO R "O \

2 CO 2 H

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10

In process I, a vinyl ester (Y = H or a group * as defined in compound I) containing the desired 6-substituent is converted to the optionally 1-substituted 4-acetoxy-2-azetidinone by a cycloaddition reaction with chlorosulfonyl isocyanate (CSI) 5 followed by reduction with an organic reducing agent such as sodium sulfite. The CSI reaction is conveniently carried out in an inert organic solvent, such as diethyl ether, at a temperature of 0 ° C or below. The reduction step can be carried out in an aqueous or aqueous-organic reaction mixture at a temperature of 0 ° or lower and at a slightly basic pH.

After formation of the 4-acetoxy-2-azetidinone, Method I can be divided into three different pathways. According to a first route (variant 1), the azetidinone is reacted with a thiolic acid XC (= O) -SH, wherein X is the desired 2-substituent, or a salt thereof, of compound I of formula I (e.g. aqueous or aqueous-organic).

Substitution of the acetoxy group causes introduction of the desired 2-substituent into the azetidinone at this stage. The replacement reaction is preferably carried out at room temperature or below and at a slightly basic pH (about 7.5). When Y = H, the cis and trans isomers of the resulting azetidinone are preferably separated (e.g., by chromatography) at this point in the process. Variants 2 and 3 above convert the 4-acetoxy-2-azetidinone to the 4-acetylthio-2-azetidinone and 4-tritylthio-2-azetidinone, respectively, by nucleophilic exchange with thioacetic acid and triphenyl-methylmercaptan, respectively (or a salt thereof, such as the sodium salt).

Next, the 4-thio-azetidinone is reacted with a giyoxylate ester HCl'OJ-COgR "wherein R" is an easily removable ester protecting group such as p-nitrobenzyl or trimethyl silylethyl, or with a reactive oxo derivative thereof such as a hydrate. in an inert organic solvent (e.g., benzene, toluene, xylene, or the like) and preferably at an elevated temperature (e.g., 50 ° C until most preferred reflux temperature). When a hydrate of the ester is used, the resulting water can be removed azeotropically or with molecular sieve. The hydroxyester compound is formed as a mixture of epimers which may be optionally purified, such as by chromatography, or used directly in the following step.

Conversion of the hydroxy ester to the corresponding chloro ester is achieved by reaction with a chlorinating agent (e.g., SOCl

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11 PC15, and the like) in an inert organic solvent (e.g., tetrahydrofuran, diethyl ether, methylene chloride, dioxane, and the like) in the presence or absence of a base, preferably an ally fatty tertiary amine (e.g., triethylamine ) or a heterocyclic tertiary amine (e.g., pyridine or collidine). The reaction is advantageously carried out at a temperature of approx. -10 ° C to room temperature, the chlorine ester compound is obtained as a mixture of epimers which can optionally be purified before use in the following step.

The phosphorane intermediate can be obtained by reacting the chloro ester with a suitable phosphine (preferably triphenylphosphine or a tri (lower) alkylphosphine such as triethylphosphine or tri-n-butylphosphine) in an inert organic solvent such as dimethylformamide, dimethyl sul foxide, tetrahydrofuran, dimethoxyethane, dioxane or et al in fatty, cycloaliphatic or aromatic hydrocarbons (e.g.

15 hexane, cyclohexane, benzene, toluene, and the like) in the presence of a base, preferably an organic tertiary amine such as triethylamine, pyridine or 2,6-lutidine. The reaction is advantageously carried out at temperatures from room temperature to the reflux temperature of the solvent system.

20 In this step, the process again separates into two paths. In variant I (where the 2-substituent has already been incorporated), the phosphorane intermediate is converted to the desired penem compound by thermal cycling in an inert organic solvent at a temperature just above room temperature to the reflux temperature of the system 25. Most suitably, the ring closure is carried out under reflux conditions. Suitable inert organic solvents include aliphatic, cycloaliphatic or aromatic hydrocarbons (e.g., benzene, toluene, hexane, cyclohexane), halogenated hydrocarbons (e.g., methylene chloride, chloroform, carbon tetrachloride), ethers (diethyl ether, dioxane, tetrahydrofuran , dimethoxyethane), carboxylic acid amides (e.g., dimethyl formamide), di C1-C6 alkyl sulfoxides (e.g., dimethyl sulfoxide), or a G1-C6 alkanol (e.g., methanol, ethanol, t-butanol) or a mixture thereof.

According to variants 2 and 3, the phosphorane is converted to a heavy metal mercaptide of the formula 12 Γ Ί DK-161520 Β s-- J-Ν P (Q) 3 Μ.

ο

CO, R "J

. L X

c III

3 or ^ • SHgGOOCH3

10 v I

J-N p (Q) 303 CO 2 R

Wherein Q is preferably phenyl or (lower) alkyl, x is 1 or 2 and M is C'u (II), Pb (II) or Hg (II) when x is 2, or Ag is Cl x is 1. The mercaptide formation is carried out by reacting the phosphorane with a salt of Hg (II), Pb (II), Cu (II) or Ag (I) or 20 with (methoxycarbonyl) mercury (II) acetate in a methanol-containing solvent. and in the presence of an organic or inorganic base such as aniline, pyridine, collidine, 2,6-lutidine, et al potassium carbonate, and the like. A preferred base is pyridine. The reaction can be carried out at room temperature or, if desired, with moderate cooling or heating. The anion (A) of the heavy metal salt may be any anion which provides a soluble salt in the selected solvent, e.g. NOg ", CH₂COO", BF ^ ", F", ClO ^ ", NOg", CNO ", etc. The mercaptide intermediate is then reacted with an acylating agent capable of introducing the portion XC (= 0) - wherein X represents the desired penem-2 to 30 substituent The acylating agent (XC (= O) - +) may be the acid XC (= O) -OH or a reactive functional derivative thereof such as an acid halide (preferably acid chloride) acid azide, acid anhydride , mixed acid anhydride, active ester, active thioester, etc. Acylation can be carried out in an inert solvent (e.g., a halogenated hydrocarbon such as methylene chloride, or an ether such as dioxane, tetrahydrofuran or diethyl ether) and when an acid is used. derivative, in the presence of an acid acceptor, such as a tri (lower) alkylamine (e.g. triethylamine) or a tertiary organic base such as pyridine, collidine or 2,6-lutidine.

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When the free acid is used, the acylation is carried out in the presence of a suitable condensing agent, e.g. a carbodiimide such as Ν, Ν'-dicyclohexyl-carbodiimide. Acylation of the mercaptide can be carried out over a wide range of temperatures, but is preferably carried out from ca. -20 to + 25 ° C. After acylation, the resulting phosphorane is cyclized as described above to form the desired pen ester.

Formation of the phosphorane via the mercaptide intermediate (variants 2 and 3) has been found to result in a product of far better purity than that obtained by the more conventional route of variant 1.

Once the carboxyl protected penem compound is formed, the protecting group can be removed by conventional de-blocking methods (e.g., hydrolysis, hydrogenation or photolysis) to form the de-blocked penem compound. Removal of the p-nitrobenzyl ester can e.g. is obtained by catalytic hydrogenation in the presence of a precious metal catalyst such as palladium or rhodium, including derivatives thereof such as oxides, hydroxides or halides, the catalyst being optionally supported on a conventional support such as carbon or diatomaceous earth.

A non-reducing aqueous or non-aqueous inert solvent such as water, ethanol, methanol, ethyl acetate, tetrahydrofuran, diethyl ether or dioxane are used. Hydrogenation can be carried out at atmospheric or elevated pressure and suitably carried out at room temperature for a period of about 1 to 5 hours, depending on the solvent used and the catalyst. If during the hydrogenation an equivalent weight amount of a base such as an all potassium metal or alkaline earth metal hydroxide or an amine is used, the product can be recovered in the form of a carboxylic acid salt. Removal of the β-trimethylsilylethyl ester, which is another valuable protecting group, is conveniently carried out by treatment with a source of fluoride ions. Other ester protecting groups can be similarly removed by methods known per se.

According to another major process (Method II), the reaction sequence is as shown below:

Method II (variant 1): Early incorporation of 2-substituent

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14 - ^ - OAc XC-SNa CH9 = CH-0Ac CSI> I - "- ς"> 2> .J, - N PH 7 · 5

O ^ H

ISLAND ISLAND

II l> SC-X __ \ _rsc-x - CHO SOCl2

oJ— ^ h V 0 ^ -NYH

CO 2 R

II cp-Y

_ .SC-X po -λ Δ Γ - ^ / —N _C1 base ^ -N \ ^ P03 O -. 0 C02R "co2R" ^ • S Y c rr> -> Y'TV3 'base 0 c02R "° C02?.' -> v>

of protection I N

o N

CO2H

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15

Process II (variant 2): Late incorporation of 2-substituent ^ OAc Γ into AcSNa \ ch2 = ch-oac _csi ^ I -JTTTT ^ 4— N \

O ^ H

_ ^. sac - ^ so c. ;> Γ CHO SOCl2

µ I „/ -N. , OH

o ^ -nXh co2r "0 ^ - γ C02R" _ ^ SAC P03 -γ SAC MA_ ^ / - N. «.Cl i_N. ^: P03 base

° ° 'T

to2R- 0 o il r — γ x-c- © ^ i — f _ ο ^ _ΝγΡ03 * J- * γ "» C02R "co2r" c02R '° COjR "_ ^ YX - f ^ S \ -x

deprotection 1 N

0 '

C02H

16

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Method II (variant 3); Late incorporation of 2-substituent - ^ OAc 0 CSNa CH, = CH-OAc CSI ^ ^ 2 ^ 1 N ΊρΗ 7.5 "

O ^ H

5 -r ^ SC03 __ ^ I CHO I SOc12 0 ^ ·% '· V SY “co2r"

r — rSC03 PO, Γ-rSC03 MA

3 ^ I _ J — N Cl base J, base O 0 C02R "co2r- oo il ~ ^ SM X.-C- © ^ rTSC ~ X *> 0J ~ K ^^ 3 _> 0J — N \ ^ PO 3 CO2R "co2R" rr> Yrv J — N '-% base j v -'- f CO2R "° CO /'

Yx_ - ^ i Γ Vx deprotection I ^ // O \

C02H

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17

As can be seen, process II is essentially the same as process I (except that Y must be H) until the thermal cyclization step which forms the 2-substituted penem compound.

However, if desired, a 6-substituent is now introduced by reacting the 2-5 penem compound with a suitable electrophilic reagent in an inert solvent (e.g., tetrahydrofuran, diethyl ether, dimethoxyethane, and the like) and in the presence of a strong base. In this procedure, the 2-penem compound can be reacted in the form of the free acid (obtained by unblocking as described above) in the presence of ca. two equivalents of base, or alternatively, a suitable 2-pen master may be used in the presence of approx. an equivalent base. Any ester which is inert to anion chemistry may be used (the reaction comprises base anion formation followed by reaction of the electrophilic reagent with the pen anion), e.g. (lower) alkyl such as methyl, ethyl, n-propyl or t-butyl, phenyl, trichloroethyl, methoxymethyl, silyl such as trimethylsilyl or t-butyldimethyl silyl, and the like. Penemasters with activated methylene groups, such as p-nitrobenzyl, are not suitable and, if the 2-penemester is of this type, it must first be bleached and either used as free acid or converted into a suitable ester. The particular base used is not critical and the usual strong bases such as sodium hydride, phenyllithium or butyllithium are suitable. Most preferably, however, a 1 in thiamine silylamide or a lithium dialkylamide such as lithium di-cyclohexylamide (LDCA), lithium diethyl amide, lithium dimethyl amide or lithium diisopropyl amide (LDA) is used. The electrophilic reagent is selected so that it is capable of developing the desired Y substituent by reaction with the anion and can e.g. be a halogen (e.g., Br 2, Ig)> an alkyl halide (e.g., CHgl) or a similar halide or an aldehyde (e.g.

CH3CH0, c6h5ch2cho).

A particularly preferred electrophilic reagent is acetaldehyde which gives rise to the hydroxyethyl-6 substituent. Introduction of the 6-substituent by this method is preferably carried out with cooling, e.g. -80 ° to 0 ° C) according to the general procedure described in Canadian Journal of Chemistry, 50 (19), 3196-3201 (1972).

After forming the desired 2,6-penem compound, an optional ester protecting group can be removed as discussed above to form the deprotected product.

The third major process (Method III) is understood from the following reaction scheme:

Method III (variants 1 and 2): 18

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SC03 __ ^ SC03

J-N ^ J-N

0 Λ 0 _JL> N-f ** 'base Å-

O B

deprotecting ^ see ^^ / ^ N '\ s ^^ MA / base

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19 Υχν_ ^ SC03 \ - ^ -N i- \ o nh O vb ΐΗ0 ° ^ co r "x-c- Θ

V 2 V

island

Y · ^ _ / SC03 Yv ^ j_pSC-X

J-N ^ OH λ-N \

o ^ o XB

C02R "

V

SOCl2 deprotection V Ψ

ISLAND

v Y li

Y- ^ u_.SC03 \ -rSC-X

J-0 ^ -1Vh

o Y H

CO 2 R

rabbits CHO

^ '\ jA2R "y_ six

oJ ~ N ^ P03 0i- “y0B

C02R "Jo2R" MA / base SOC1- Ψ v

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20 "Vts« ¥ i? |. \ _ ^ - sc-x o-i ^ V ^ 03!] [0 ^ "% ^

co2r "I

CO 2 R 0

II

\ / <$) p03 o \, base Y-> H V n, ^ - SC-X Y o I V-rsc'x. Jv · C02R "[C02R-> Δ Ψ - - Δ Y Ψ V ^ -s

\ Y V

1 y-x i— \ jI /) - x O J-N ^ / 0 CO R "0 \ 2 CO H" 2 deprotection ^ deprotection

V

YvV-r ^ \ JXr VrVx o \ J N / co2h O \ co2h s = blocking nitrogen for ring nitrogen.

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The 4-tritylthio-2-azetidinone of method III is formed as described by method II (variant 3). The azetidinone ring nitrogen is then protected with a conventional readily removable blocking group such as triorganosilyl (e.g. trimethylsilyl or t-butyl in methylsilyl), methoxymethyl, methoxyethoxymethyl, tetrahydropyranyl, and the like.

Insertion of the desired Y substituent into the 1-position of the azetidinone is then achieved by reacting an appropriate electrophilic reagent with the N-protected azetidinone in the presence of a strong base (reaction conditions as described above for Method II). At 10 this point, the process separates into two paths depending on the time of azetidinone unblocking.

According to a first route, the N-protected intermediate is anchored off by conventional methods (e.g. acidic hydrolysis) and then converted to the 2,6-penem compound via ester formation, chlorination of the hydroxyester, conversion of the chloroester into a phosphorane, conversion of the phosphorane to a heavy metal mercaptide, acylation of the mercap time with XC (= 0) - +, thermal cyclization of the resulting phosphorane to form the 2,6-pen ester, and removal of the carboxyl protecting group. The reaction conditions for these steps are as described in connection with Method II (variant 3).

An alternative pathway involves conversion of the N-protected azetidinone to a heavy metal mercaptide, acylation of the mercaptide with the portion XC (= 0) - +, removal of the N-protecting group, reaction of the deprotected azetidinone with the glyoxylate ester, chlorination, reaction of the chloroester. with the phosphine to form the phosphorane, ring closure of the phosphorane to form the penemester and removal of the carboxyl protecting group to form the 2,6-penem compound. The reaction conditions for these steps are as described above.

In the preparation of the 2-penem or 2,6-penem compounds according to the above methods, free functional groups in the substituents X or Y which do not participate in the reaction can be temporarily protected in a manner known per se, such as free amino groups at acylation, triethylation or silylation, free hydroxyl groups, e.g. by etherification or esterification, mercapto groups by esterification, and free carboxyl or sulfo groups, e.g. by esterification, including silylation. Once the reaction has taken place, these groups can, if desired, be released individually or together in a manner known per se.

Furthermore, it is possible in the compounds of formula I to be functional

DK 161520B

22 to modify the 2- and / or 2,6 substituents during or at the end of the reactions in a manner known per se to obtain other substituents which fall within the scope of the invention. For example, carbonyl groups can be reduced to all alcohol groups, unsaturated aliphatic groups can be halogenated, amino groups can be alkylated or acylated, nitro groups can be converted to hydroxyamino and amino groups, hydroxyl groups can be etherified or esterified, etc.

The free penic acids can be converted into pharmaceutically acceptable salts thereof. Salts can be formed by reacting the free acid with a stoichiometric amount of a suitable non-toxic acid or base in an inert solvent followed by recovery of the desired salt, such as lyophilization or precipitation. Resulting mixtures of isomers can be separated into the individual isomers in a manner known per se.

Mixtures of diastereomeric isomers may e.g. is separated by fractional crystallization, adsorption chromatography (column or thin layer chromatography) or other suitable separation methods. Resulting racemates can be cleaved into the antipodes in the usual manner, e.g. by forming a mixture of diastereomeric salts with optically active salt-forming reagents, separation of the diastereomeric salts, conversion of the salts into the free compounds, or by fractional crystallization from optically active solvents.

The present invention provides, as mentioned above, a process for the preparation of a compound according to claim 1.

The present invention also encompasses the compounds used as intermediates used as starting materials.

The free penic acids and pharmaceutically acceptable salts thereof of this invention have been found to be potent broad-spectrum antibacterial agents valuable for treating infectious diseases in animals and humans, caused by both gram-negative and gram-positive organisms. The compounds are also valuable as agents for treating mastitis in cattle.

The 2-penic acids provided by the invention (and physiologically cleavable esters and pharmaceutically acceptable salts thereof) (i.e., compounds of general formula I wherein Y = H) possess antibacterial activity per se and are also valuable intermediates (preferably on their carboxyl protected form) to prepare the 2,6-disubstituted penem compound I via anion formation and reaction with an electrophilic reagent.

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23

The active compounds provided by the invention may be formulated as pharmaceutical compositions comprising, in addition to the active ingredient, a pharmaceutically acceptable carrier or diluent. The compounds can be administered both orally and parenterally. The pharmaceutical compositions may be in solid form such as capsules, tablets or dragees, or in liquid form such as solutions, suspensions or emulsions. For the treatment of bacterial infections in humans, the subject compounds can be administered orally or parenterally in an amount of about 5 to approx. 200 mg / kg / day and preferably about 10 mg. 5 to approx. 20 mg / kg / day in divided doses, e.g. three or four times daily. They are administered in dosage units which e.g. contains 125, 250 or 500 mg of active ingredient with suitable physiologically acceptable carriers or diluents.

The following examples illustrate the preparation of starting materials 15 and end products of the invention. All temperatures are in ° C. For the sake of simplicity, some examples have used some abbreviations. The definitions of the less obvious abbreviations are the following: CSI chlorosulfonyl isocyanate pet. ether petroleum ether 20 kp. boiling point n.m.r. nuclear magnetic resonance h hour ether diethyl ether (unless otherwise stated)

Cel ite trademark for diatomaceous earth from Johns-Manville 25 Products Corporation psi pounds per square inch r.t. room temperature PNB p-nitrobenzyl m.p. Melting point 30 LAH lithium aluminum hydride n-BuLi n-butyllithium MIBK methyl in sobutyl ketone

A C

Tr-C (C6H,) 3 Me CH3-THF tetrahydrofuran

Ph phenyl DMF dimethyl formamide

DK 16152CB

24 TEA tri ethyl amiη PNBG p-nitrobenzylglyoxylate THP tetrahydropyranyl TFA tri fluoroacetic acid 5 HMPT (or HMPA) hexamethylphosphoric triamide LDA lithium diisopropylamide

Ac CH3CO-

Ms CH3 SO2- DMAP 4-dimethyl aminopyridine 25

DK 161520 B

Preparation of starting materials Preparation of 4-tritylthio-2-azetidinone intermediates 05 1) 1- (trimethylsilyl) -4-tritylthio-2-azetidinone rT. rf '

lu JT -N

0J cr \ s. (Me) ^ A solution of 4-tritylthio-2-azetidinone (345 mg, 1 mmol) 1,1,1,3,3,3-hexamethyldisilazane (80 mg, 0.5 mmol) and chlorotrimethylsilane (55 mg, 0.5 mmol) in dichloromethane (20 ml) was heated at reflux for 18 hours. Concentration of the reaction mixture gave the title compound in virtually pure form. δ 20 (ppm, CDCl3): 7.32 (15H, m, aromatic compounds), 4.22 (1H, dd, H-4), 2.67 (1H, dd, J = 4.1, J = 16 , H-3), 2.22 (1H, dd, J = 2.2, J = 16, H-3), 0.3 (9H, s, CH 3).

2) 1- (t-Butyldimethylsilyl) -4-tritylthio-2-azetidinone 1- [0 * 3 '-f3 Z-11L> Π »/ ¾ 30 0 o Si-CH 3 c (ch 3) 3 35 26 * <· <1

DK 161520 B

Triethylamine (1.62 mL, 11.6 mmol) was added dropwise over 5 minutes to a cooled (0 °) and stirred solution of 4-tritylthio-2-azetidinone (3.5 g, 10.1 mmol) and chloro-t-butyldimethylsilane (1.68 g, 12.7 mmol) in DMF (35 ml). The reaction mixture was stirred at room temperature for 18 hours, diluted with water (250 ml) and ether (2Q0 ml). The organic phase was washed with water (3 x 50 ml), dried and concentrated to give an oil (4.33 g). Crystallization from pentane gave a total of 4.1 g (89%) of the title compound as a white solid, m.p. 113-114 °. δ (ppm, CDCl 3): 7.45 (15H, m, aromatic compounds), 4.2 (1H, dd, H-4), 2.63 (1H, dd, J = 4, J = 16, H -3), 2.13 (1H, dd, J = 2, J = 16, H-3), 1.0 (9H, s, t-Bu), 6.35- (6H-, s, Me) . vc = 0 1735 cm

Analysis calculated for C₂gH33NNOSSi: C, 73.15; H, 7.24; N, 3.05; S, 6.97%.

Found: C, 73.27; H, 7.32; N, 2.97; S, 6.94%.

3) 1-Methoxymethyl-4-tritylthio-2-azetidinone sc4>, sc <f> rf - - rf 25

A solution of 4-tritythio-2-azetidone (1.38 g, 4.0 mmol) in THF (10 ml) was added to a well stirred suspension of sodium hydride (200 mg of commercial product 50%, 4.1 mmol, washed with pentane). ) in THF 30 (10 ml) kept at -15 °. Methanol (12 drops) was added and the mixture was not stirred at -15 ° for 0.5 hour. Methoxymethyl bromide (0.58 g,

(4.6 mmol) was added and the mixture stirred for 2 hours, diluted with ether, washed with water and brine, dried and concentrated to give an oil (1.72 g). Crystallization from pentane gave a white solid (1.41 g) m.p. 72-76 °. δ (ppm, CDCl 3): 7.3 (15H, m, aromatic compounds), 4.4 (3H, m, NCH₂O and H-4), 3.22 (3H

C s, CH 3), 2.76 (2H, m, H-3).

27

DK 161520 B

4) 1- (Methoxyethoxymethyl) -4-tritylthio-2-azetidinone 05 I |

To a suspension of tetrabutylammonium bromide (322 mg, 1 mmol) 10 and potassium hydroxide (85%, 70 mg, 1.1 mmol) in dichloromethane (10 ml) cooled to 5 ° was added with vigorous stirring 4-tritylthio-2-azetidinone (345 mg, 1 mmol) and methoxyethoxymethyl chloride (187 mg, 1.5 mmol). The mixture was stirred at room temperature for 2 hours, the solvent was evaporated and the residue partitioned between water and ethyl acetate. The dried organic phase was concentrated to give a viscous oil (415 mg). Purification by column chromatography on silica gel eluting with ether (5%) - dichloromethane afforded the title compound (206 mg, 48%) as an oil. 6 (ppm, CDClCI): 7.30 (15H, m, aromatic compounds), 4.57 (2H, AB quartet, N-Cl-O), 4.46 (1H, dd, H-4) , 3.50 (4H, s, OCH 2 CH 2 O), 3.30 (3H, s, CH 3), 2.75 (2H, m, H-3).

5) 1- (2L-Tetrahydropyranyl) -4-tritylthio-2-azetidinone Γ-Τ3. 'rT3 ..

30 ¢ / -VH cT

35

DK 161520B

28 n-Butyflithium (1.6 m, 1.6 ml, 2.56 mmol) was added dropwise to a solution of 4-tritylthio-2-azetidinone (863 mg, 2.5 mmol) in THF maintained at -78 °. After stirring for 15 minutes, 2-chlorotetrahydropyran (560 mg, 4.7 mmol) was added and the reaction mixture was allowed to reach room temperature over 1.5 hours. The reaction solution was diluted with ethyl acetate, washed with brine, dried and concentrated to give an oil (635 mg). Column chromatography on silica gel and elution with dichloromethane ether afforded a mixture of the isomeric title compounds corraminated with a bit of starting material.

V

10 material. 6 (ppm, CDCl 3): 7.28 (15H, m, aromatic compounds), 4.4 (H, dd, H-4), 2.9-2.2 (2H, m, H-3), 4 , 1-3.2 and 2.2-0.7 (tetrahydropyranyl).

6) Preparation of 4-tritylthio-1- (p-nitrobenzyl-2,2-triphenylphosphoranylidene-2'-acetate) -2-azetidinone | -γ5εΦ3 O '^ V1' * 3 CO PNB 2 1- (V-carboxylic acid) 1 '-hydroxymethyl) -4-methylthio-2-azetidinone triethylamine salt STr I- (+ fH0 TEA, _ ^ STr

J - NH CO_H * XH2 ° 'Mol. sTgter * I J

U 2 r A — N. Λ OH

THI- <T ~ Y .TEA

30 CO 2 H

35

DK 161520B

29

To a solution of 4-tritylthio-2-azetidinone (3.5 g, 10.15 mmol) in tetrahydro-uranium (8 ml) was added triethylamine (1.42 ml, 10.15 mmol) and glyoxylic acid hydrate (1.02 g , 10.15 mmol). The mixture was stirred at room temperature with 4Å molecular sieves (8 ml volume) for one hour 05 and allowed to stand at room temperature overnight. The solidified mixture was diluted with methylene chloride and filtered; the filtrate was evaporated and the residue crystallized from pentane to give 5.18 g (98%) of the title compound as a white solid, m.p. 112-115 ° C; ir vmax: 3100-3600, and 1755 cm “1; 1 Hmr (CDClip 10 6: 7.3 (15H, m), 4.92 and 5.10 (1H, 2s), 4.50 (1H, dd, J = 3Hz), 3.0 (1H, dd, J = 15Hz, J = 7Hz), 3.1 (6H, q, J = 7Hz), 2.70 (1H, dd, J = 15Hz, J = 3Hz), 2.0-3.5 (2H, m) and 1.21 ppm (9H, t, J = 7Hz).

* The molecular sieves were dried at 150 ° C for 18 hours.

1- (11-carboxy-11-chloromethyl) -4-methylthio-2-azetidinone STr _ STr 20 | "T ♦ *«, -: - * · ΓΤ <λ ~ 'γ0Η, TEA ™ 2 2 ON ^ rr 'C 1 -C

CO H CO H

2 2

A cooled (ice bath) solution of the triethylamine salt of 1- (1'-carboxy-1'-hydroxymethyl) -4-methylthio-2-azetidinone (1.04g, 2.0mmol) in methylene chloride (5ml) was treated dropwise, under Ng / with thionyl chloride (0.16 mL, 2.2 mmol) in methylene chloride (2 mL). The solution was stirred at room temperature for 20 minutes and concentrated.

The residue was diluted with benzene and filtered over a bed of 30 Celite / charcoal. The filtrate was evaporated in vacuo to give 870 mg (quantitatively) of the title compound as an amorphous solid. It was used in the next step without further purification, ir vmax: 1775 cm; 1 Hmr (CDCl 3) 6: 9.22 (1H, bs), 7.27 (15H, m), 5.3 and 5.2 (1H, 2d, J = 2Hz), 4.6 (1H, m) and 2.8 ppm (2H, m).

35 30

DK 161520 B

1- (11-carbo-p-nitrobenzyloxy-11-chloromethyl) -4-trityl-thio-2-azetidinone STr ©1 © 05 .- / He N = CH Cl STr I + PNB-OH 1 _. Γ

CHCl3 O2 - ^ C1 L · “Ln pyridine / THF I

CO PNB

To a cooled (ice bath) solution of DMF (0.17 mL, 2.2 mmol) in chloroform (4.4 mL) was added dropwise oxalyl chloride (0.19 mL, 2.2 mmol). The mixture was stirred for 5 minutes in ice, then for 20 minutes at room temperature. The solution was cooled in an ice bath and treated dropwise with 1- (11-carboxy-1, -chromethyl) -4-tritylthio-2-azetidinone (854 mg, 2 mmol) in chloroform (2 ml) followed by a 1 m solution of pyridine in tetrahydrofuran (2.2 ml, 2.2 mmol); the solution was stirred at room temperature for 30 minutes, cooled to 0 ° C and treated dropwise with paranitrobenzylal carbon (370 mg, 2.2 mmol) in tetrahydrofuran / chloroform (1: 1, 2 ml) and triethylamine (0.31 ml) , 2.2 mmol). The solution 20 was stirred at room temperature for 30 minutes and then evaporated.

The residue was diluted with benzene and filtered over a Celite / charcoal bed and the filtrate was evaporated in vacuo. The crude chloride ester was purified on a silica gel pad (5 g) and eluted with methylene chloride to give 790 mg (70%) of the title compound as a beige powder.

Trituration in ether gave a white solid, m.p. 168-169 ° C.

ir vmgx: 1780, 1760 cm -1; qHmr (CDCl 3) 6: 8.15 (2H, d, J = 9Hz), 7.49 (2H, d, J = 9Hz), 7.3 (15H, m), 5.75 and 5.35 (1H) , 2s), 5.3 (2H, s), 4.55 (1H, m), 2.8 (2H, m). This compound was identical to an authentic sample prepared by reaction of 4-tritylthio-30 2-azetidinone with p-nitrobenzylglyoxylate followed by thionyl chloride treatment.

35 31

DK 161520 B

^ Chloroform was left on molecular sieves (3Å) for 18 hours before reaction (to remove any trace of alcohol).

Example 1 05 1- (p-Nitrobenzyloxycarbonylmethyltriphenylphosphoranyl) -4- (silver-mercaptidyl) -2-azetidinone SAg ΓΊ 10

0 T

C02PNB

STr .OAc _ / 15 rf _ ™ _> i

j— Nh Na0Me H

1 2 20 3

A methanol (90 cm) suspension of triphenylmethylmercaptan (13.8 g, 0.05 mmol) was degassed for 0.5 hour with a stream of nitrogen. The mixture was cooled to 0 ° C and sodium hydride (2.4 g, 0.05 mole, 50% oil dispersion) was added portionwise. The resulting solution was stirred for 5 minutes and 4-acetoxyazetidinone (7.7 g, 0.059 mol) in water (55 cm) was added rapidly. 4-Tripheoylmethylmercaptoazetidinone (2) precipitated immediately. The mixture was stirred for 4 hours at room temperature. The solid was filtered off, washed with water and dissolved in methylene chloride. The methylene chloride solution was washed with dilute HCl, water, aqueous sodium bicarbonate, water and brine and dried over IVIgSO4 (89.8%, mp 146.5-147.5 ° C).

35

DK 161520B

32

Analysis calculated for ~22 ° C 19.5: C, 76.49; Η, 5.54; Ν, 4.05; S, 9.28 Found: C, 7.54; Η, 5.60; Ν, 4.00; S, 9.36. Δ (ppm, CDCl 3) 7.60 - 7.10 (15H, m, H-trityl), 4.62 (1H, bs, NH), 4.40 = 3.0, J, δ = 5, H-4), 3.24 (1H, ddd,

Jgem = 15 'J3-4 cis = 5' J3-NH = 1'8 '^ 2'81 (1H' ddd 'Jgem = 15 / J3-4 trans = 3.0 / J3-NH = 1'2' H = 3 (CHCl 3) 1760, vNH 3340. | j 10 STr ϊ »0, 511 I-f" STr

ri - = * = - rf o „♦ P, 0B

CO PNB CO PNB

2 z 15 2 2

Hydrated p-nitrobenzylglyoxylate (4.54 g, 0.02 mole) and azetidinone 2 (6.90, 0.02 mole) were refluxed in benzene through a 20 Dean Stark condenser filled with 3 Å moiety, for 24 hours.

Additional glyoxylate (2 x 454 mg, 2 mmol) was added with a reflux period (18 hours) after each addition. The mixture was diluted with ether, washed with 5% aqueous HCl, water, aqueous 5% NaHCO 3, water and brine. It was dried over MgSO4 (12 g, quantitative).

A small fraction of the epimeric mixture was separated on a silica gel plate (CH 2 Cl 2 ether 6: 4).

In Summer A:

Rf = -0.87, m.p. = 170.5-171.5 ° δ (ppm, CDCl 3) 8.07 (2H, d, J = 9, Hm aromatic), 7.45 (part of d, 30H aromatic), 7.40-7, 00 (15H, m, trityl), 5.25 (2H, s, CH2-PNB), 4.75 (1H, s, HCO), 4.37 (1H, dd, trans = 3, ds = 4, H -3), 2.83 (1H, dd, Jgem = 16, J4_3 ds = 4, H-4), 2.10 (1H, dd,

Jgem = 16 'J 4-3 trans = 3' H'4> '^ 42 <b-s "0H> * vc = o <CHCI3> 1770, 1760 (shoulder), VNC> 2 1525, vQH 3475.

33

DK 16152GB

Isomer B:

Rf = 0.75, m.p. = 152-153 ° δ (ppm, CDCl 3), 8.13 (2H, d, J = 9, Hm aromatic), 7.47 (2H, d, J = 9, Ho aromatic), 7.40 - 7, 00 (15H, m, trityl), 5.30 (3H, s, 05 CH2-PNB, HCO), 4.45 (1H, t, J = 3.5, H-4), 2.90-2, 70 (2H, AB part of ABX, H-4), 1.55 (bs, OH), v _ (CHCL) 1767, 1755 (shoulder), VNO 1525, v ~ u 3500.

C — O o c. Url 10 IU. STr / STr

I — SOC12 —I

In OH pyildli 1_N Cl (/ —σ γ

io2PNB · éo2PNB

15 3 4

ISLAND

A cold (-15 °) THF- (150 cm, dried over molecular sieves) 1 2 3 4 5 6 7 8 9 10 11 35 solution of azetidinone 3 (12 g, 21.7 mmol) was treated with pyridine 2

ISLAND

3 (1.9 g, 24.1 mmol, 1.94 cm) and dropwise with thionyl chloride (2.86 4 3.5 g, 24 mmol, 1.88 cm) under nitrogen atmosphere. The mixture was stirred for 45 minutes at -15 °. The precipitate was filtered off and washed with benzene. Evaporation of solvent gave a residue which was taken up in benzene and treated with activated charcoal (11.7 g, 94%, 7 recrystallized from chloroform).

Δ (ppm, CDCl 3) 8.17 (2H, d, J = 8, Hm aromatic), 7.67 - 7.00 9 (17H, m, Ho aromatic, Tr-H), 5.80 (s, HC-CI), 5.37, 5.33 (2s, HC-CI, CH2-PNB, 4.81 (1H, m, H-4), 3.27 - 2.40 (2H, m, H -3) 11 vc_o (KBr movie) 1785, 1770 VN02 1525.

DK 161520 B

34 STr ^ STr rf φ3ρ, [; 2,6-Lutidine

05 I T

CO PNB co2pnb 4 5 vq 10 A THF (100v cm, distilled over LAH) solution of chlorazetidinone 4 (11.6 g, - 20.2 mmol) was treated with triphenylphosphine (7.86 g, 30.0 mmol ) and 2,6-lutidine (2.36 g, 2.56 cm 2, 22.0 mmol). The mixture was refluxed for 72 hours. The bottom surface was filtered off and washed with ether. The organic solution was washed with 2% aqueous 15 HCl and 5% aqueous hydrogen carbonate and dried over IIIgSO Solvent evaporation gave a residue which was purified through a silica gel pad (200 g). The desired phosphorane was eluted with 30.40 and 50% ether-benzene (11.4 g, 70.4%, mp 201-202 °).

Analysis calculated for ΟΟ ^ΗΗΙ: 20 C, 73.57; H, 5.04; N, 3.50; S, 4.01.

Found: C, 73.58; H, 4.91; N, 3.44; S, 3.87.

vc = 0 (CHClip 1740, v phosphorane (1620, 1610), VN02 1525).

25 _ ^ ΤΓ, AgN03 _ ^ SAg / -Ν ^ ΡΦ 3 pyridine

CO PNB I

30 2 CO 2PNB

5 6 35

DK 161520 B

4-Trityl mercaptoazetidinone 5 (1.6 g, 2 mmol) was dissolved in CH 2 Cl 2 (20 cm 3) and the solvent was evaporated at 55-60 °. Phosphoran 5 at 55-60 ° was dissolved in preheated (55-60 °) methanol (32 cm 3). Immediately upon obtaining a methanolic solution of 6, this 05 was treated with a preheated (55-60 °) mixture of methanolic 0.15 m silver nitrate solution (16 cm, 1.2 eq) and pyridine (174 mg, 178 μΙ, 2.2 mmol, 1.1 eq.) The heating bath was removed immediately after. The mixture was stirred at room temperature for 2 hours and at 0 ° for 1 hour. The silver mercaptide 6 was filtered off, washed twice with cold (0 °) methanol and three times with ether. (1.12 g 84.5%, mp 130-135 ° dec.).

vc = Q (CHCl 3) 1795, 1725 (shoulder), v phosphorane (1620, 1605), VN02 1530.

Example 2 1- (p-Nitrobenzyloxycarbonylmethyltriphenylphosphoranyl) -4- (silver mercaptidyl) -2-azetidinone.SCOCH Shq rY-3 K2CO3-A9K '° 3, Γ-Τ

20 J — IMe0H J— H

0 (J = PPh3 0 ^ j = PPh3

COOPNB COOPNB

A solution of phosphorane 7 (1.796 g, 3.0 mmol) in chloroform (3 ml) was diluted with methanol (90 ml), cooled at 0 ° C under a nitrogen atmosphere and treated successively with silver nitrate (0.51 g, 3.0 mmol) and potassium carbonate (0.33 g, 2.4 mmol). The reaction mixture (protected from light) was stirred at 0 ° C for 15 minutes, then the cooling bath was removed and stirring was continued for 3 hours. The reaction mixture was cooled to -10 ° C, stirred for 1 hour and filtered; the silver mercaptide was washed successively with cold methanol and ether; 1.91 g, m.p. 138-145 ° C, decomp., 96%. IR (nujol) cm 1748, 1620 and 1605.

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36

An analytical sample was obtained by preparative thin ag chromatography (ethyl acetate); mp. 140-145 ° C, decomp .; Calcd. H, 3.65; N, 4.22; S, 4.83.

Found: C, 54.11; H, 3.48; N, 3.92; S, 4.62.

Example 3 1- (p - N itrobenzy loxycarbony I methyltri phenyl phosphoranyl) -4- (silver mercaptidyl) -2-azetidinone 10 A. Use of aniline as a base SCOCH-I-f Aniline ,. AgNO -f '^ 15 N \ MeOH V y - n 0 ^ c = pph, cr \' 1 3 C = PPh

COOP NB 1 J

COOPNB

7 20 -

A solution of phosphoran 7 (1.8 g, 3.0 mmol) in chloroform (4 ml) was diluted with methanol (90 ml), cooled to -15 ° C under nitrogen atmosphere and successively treated with silver nitrate (0.56 g, 3.3 mmol) and aniline (1.5 ml, 16.5 mmol). The reaction mixture 25 (protected from light) was stirred at -15 ° C for 0.5 hour, then the cooling bath was removed and stirring was continued for 24 hours. The reaction mixture was cooled to -10 ° C and stirred for 1 hour before filtration; the silver mercaptide was washed successively with cold methanol and ether; 1.55 g, m.p.

-1 114-115 ° C, decomp. 77.9%. IR (nujol) cm; identical to the compound of Example 2.

35

DK 161520 B

37 Silver 1- (paranitrobenzyl-2l-triphenylphosphoranylidene-21 ·· acetate) -2-azetidinone-4-thiolate 05 B. Use of 4-dimethylaminopyridine (DMAP) as a base _ SCOCH_ SAg -S J AgNO ^ / DMA? - {10 CH2 Cl2 / CH3 OH *

CO ^ PNB CO ^ PKB

A solution of the above S-acetylphosphorane (17.96 g, 15 mmol) in methanol and dichloromethane (1: 2, 450 ml) was purified with nitrogen (5-10 min), cooled to 5 ° C and treated successively with silver nitrate (5.35 g, 31.5 mmol) and 4-dimethylaminopyridine (3.85 g, 31.5 mmol). The ice bath was removed and the solution was refluxed vigorously for 2 hours and then stirred at room temperature for 1 hour. The colored reaction mixture was treated with charcoal, filtered and evaporated. The residue was redissolved in a minimum amount of dichloromethane and added dropwise with stirring to cold methanol (300 ml). The precipitated silver salt was collected by filtration, washed with ether and dried; 18.1 g (91%); ir (CHCU) νm: 1745 (C = 0 β-lactam) and 1607 cm -1 at max 25 (C = 0 ester).

Silver 1- (paranitrobenzyl-2l-triphenylphosphoranylidene-2 ”- acetate) -2-2-azetidinone-4-thiolate 30 C. Use of diazabicycloundecene (DBU) as a base SCOCH SAg -1 3 AgNO / ^

[----- ► I

J — N Ρφ DBU 'Me0H J N Ρφ, 35 a Ύ 3 Y' 3 C02PNB co ^ pnb

DK 161520 B

38

The above S-acetylphosphorane (36.0 g, 0.060 mol) was dissolved in methylene chloride (120 ml). The solvent was evaporated to give an oil. The resulting oily residue was dissolved in hot (35 ° C) methanol (240 ml) and treated quickly with a methanolic (420 05 ml) solution of silver nitrate (10.68 g, 0.0628 mol). The resulting solution (or suspension) was stirred at room temperature for 5 minutes, cooled (ice bath) and a DBU (8.96 mL, 0.060 mol) solution in methanol (20 mL) was added over a period of 5 minutes. The mixture was stirred for 5 minutes. The solid was filtered, washed once with cold (00C) methanol and ether and dried under vacuum; 37.0 g (93%); ir (nujol naill) v (c = o) and 1600 cm 2 (phosphorane). | ΓΠαΧ * '| D. Use of pyrrolidine as a base in Silver-1- (paranthtrobenzyl-2'-triphenylphosphoranylidene-211-in acetate) -2-azetidinone-4-thiolate scoch __ ^ A9

| j _Pyrrolidine I J

J N AgNO J— N

20 0 ^ -c-pph 3 · 0 ^ c-pph

I 3 I

COOPNB COOPNB

To a cold (0 ° C) solution of 4-acetylthio-1- (paranitrobenzyl-2 "-25-triphenylphosphoranylidene-2" acetate) -2-azetidinone (0.60 g, 1.0 mmol) in CH MeOH (4 ml), a solution of AgNO 4 in MeOH (0.14 n, 7.86 ml, 1.1 mmol) and a solution of pyrrolidine (0.92 ml, 1.1 mmol) was added. MeOH (2 ml). The cooling bath was removed and the reaction mixture was stirred for 1.75 hours, cooled to -10 ° C, stirred for 0.25 hours and filtered. The solid was washed with cold MeOH and dried in vacuo; 0.548 g, m.p. 115 ° C, 82.4%. ir. (nujol) v: 1755 (C = 0) and 1600 cm (aromatic).

35

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39

Example 4

Mercury (II) - [2 '- triphenylphosphoranylidene ^' - acetate] -2-azetidinone-4-thiolate 05 STr.

S 'Hg (OAc) 2 J — N \ 0 v'C = PPh I 3

C02pNB

10 SJ'Hg ofl- ^ PPh3

15 J

CO PNB 2

II

A solution of J (2.4 g, 3 mmol) in dichloromethane (15 mL) was cooled to 5 ° C and treated with a solution of mercury acetate (0.525 g, 1.65 mmol) dissolved in methanol (15 mL). After stirring at 5 ° C for 2 hours, the solvent was evaporated and the residue was redissolved in dichloromethane and washed with cold water. After drying (MgSO4) and treatment with charcoal, the organic solution was evaporated to give a foam which crystallized on trituration in ether. Yield: 1.73 g (91%), m.p. 123-127 ° C, ir (CHCL) 1745 cm -1 (v β-lactam) 1608 cm (phenyl).

Example 5 A. Preparation of 3- (11-hydroxy-11-ethyl) -1-methoxy-methyl-4-tritylthio-2-azetidinones. ^ sc <f> 35 γΧ 3 _ * "jnf

DK 161520 B

An oil (0.228 g) which was chromatographed on 10 g of silica gel. A mixture of benzene and ethyl acetate (6: 4) gave 0.106 g (62% recovery) of substrate and a mixture of the two isomeric alcohols which were separated by chromatography on thick layer plates (same solvent system). The alcohol 05 with the high Rf (0.033 g, 17%) was identical to the above isomer (isomer C): m.p. 188.5-189 ° C (ether-dichloromethane); the low Rf alcohol (0.030 g, 16%) (isomer B) was obtained in the form of an oil which readily crystallized from hexanes: m.p. 94-95 ° C. ir (CH9CL) v 3600 (OH), 1760 cm cm 1 (c = o); 1 Hmr (CDCL) δ: 6.9-7.5 (15H, m / aromatic), 4.2 (2H, center of ABq, J = 11.5, CH2-0-CH3), 4.28 (1H , d, J = 2.0, 4-H), 3.65 (1H, center of a wide sextet, H-1 ') / 3.3 (1H, dd, ^ 4 trans = 2/5 / J3. = 5.5, - H3.) / 3.15 (3H, s, O-CH3), 1.55 (1H, broad's, OH-1 '), 1.05 (3H, d, J = 6 , 5, H-2 '); Analysis calculated for C 26 H 27 NO 3 S: C, 12.02} H, 6.28; N, 3.23; S, 7.39 Found: C, 71.77; H, 6.36; N, 3.15; S, 7.43%.

B. Preparation of. Trans-3-acetyl-1-methoxymethyl-4-tritylthio-2-azetidinone o, ττ ° Φ3 -Γj LDA. t CH - 1 · 25 In EtOAc 'V 3 1 30 Lithium diisopropylamide was prepared under nitrogen atmosphere at -78 ° C as usual from diisopropylamine (0.34 ml, 2.4 mmol) and n-butyllithium (1.1 ml of a 2.2 m solution in hexane, 2.4 mmol) in THF (3 ml). A solution of 1-methoxymethyl-4-tritylthio-2-azetidinone (0.78 g, 2 mmol) in THF (3 ml) was added dropwise and, after stirring at -78 ° C for 20 minutes, ethyl acetate (0, 53 g, 6 mmol) in one portion and stirring was continued for 0.75 hours at -78 °. The reaction mixture was diluted with ether and washed with one

DK 161520 B

41 a) (1 'S / 3S / 4R and 11R, 3R, 4S) isomer (isomer C)

A solution of lithium diisopropylamide was prepared in THF (5 ml) at -78 ° C from n-butyllithium (1.6 m, 1.0 ml, 1.6 mmol) and diisopropylamine (0.25 ml, 1.84 mmol) . After 30 minutes to-05, a solution of 1-methoxymethyl-4-tritylthio-2-azetidinone (491 mg, 1.42 mmol) in THF (6 ml) was added dropwise and the solution was stirred for 15 minutes. Acetaldehyde (3.0 ml) was added dropwise and after 20 minutes water (30 ml) was added. The mixture was acidified to pH 3 with 2% HCl and extracted with ethyl acetate (5 x 20 ml). The combined organic phases were washed with brine, dried and concentrated to give an oil which crystallized after trituration with ether: 440 mg, 80%, m.p. 188.5 to 189 ° C; 1 Hmr (CDCl 3) 6: 7.3- (15H, m, aromatic), 4.37 (2H, ABq, N-CH2 O), 4.32 (1H, d, J = 2, H-4), 3, 17 (3H, s, OCH 3), 3.32-2.70 (2H, m, H-3 and H-5), and 1.12 ppm (3H, d, J = 7, CH 3);

Analysis calculated for C 26 H 27 NO 3 S: C, 72.02; H, 6.28; N, 3.23; S, 7.39 Found: C, 71.99; H, 6.02; N, 3.21; S, 7.40%

B) VS, 35.4R and 1'R, 3R, 4S) and (TR, 3S, 4R and 1'S, 3R, 4S)

(isomers C and B).

A solution of lithium diisopropylamide (0.482 mmol) was prepared at -78 ° C in dry ether (3 ml) from butyllithium (0.191 ml 2.52 m solution in hexane, 0.482 mmol) and diisopropylamine (0.067 ml, 0.482 25 mmol). After 20 minutes, a solution of (4R and 4S) of 1-methoxymethyl-4-tritylthio-2-azetidinone (0.171 g, 0.439 mmol) in a mixture of dry ether (1 ml) and dry THF (1 ml) was added dropwise. and the resulting clear solution was stirred at -78 ° C for 15 minutes. A solution of tetrabutylammonium fluoride (0.96 ml of a 0.5 m solution 30 in THF, 0.48 mmol) was then added. A precipitate formed during the development of a pale pink color. After 5 minutes at -78 ° C, the reaction mixture was quenched with freshly distilled acetaldehyde (0.2 ml, excess) and stirring was continued for a further 15 minutes. The work-up was done by adding a saturated solution of 35 ammonium chloride and extraction with ethyl acetate (2 x 25 ml). The combined organic phases were washed with brine and dried over anhydrous magnesium sulfate. Evaporation of the solvent in vacuo gave

DK 161520B

43 ammonium chloride solution, water and brine, dried and concentrated to give an oil (0.7 g). Purification was achieved by chromatography over silica gel (20 g) by eluting with increasing amounts of ether in benzene. The relevant fractions were concentrated to give the title material as a colorless oil (0.32 g, 37%); 1 Hmr in (CDCl 3) 6: 7.7-6.8 (15H, aromatic), 4.85 (1H, d, J = 2, H-4), 4.5 (2H, s, N-CH ), 3.9 (1H, d, J = 2, H-3), 3.22 (3H, s, CH 3) and 2.0 ppm (3H, s, CH 2); ir v: 1770, 1710 cm 1.

C. ΠΊαΧ 10 C. Preparation of trans-3-acetyl-1- (t-butyldimethylsilyl) -4-tritylthio-2-azetidinone 15 rVC * 3 ™, A-fSC * 3 in t-Bu EtOAc. '-N t-Bu i

<r ~ NsK

X! CH3) 2 x "" 3> 2 20

Diisopropyllithium amide was prepared as usual from diisopropylamine (0.18 ml, 1.24 mmol) and n-butyllithium (0.78 ml of a 1.6 m solution in hexane, 1.24 mmol) in THF (8 ml). A solution of 1- (t-butyldimethylsilyl) -4-tritylthio-2-azetidinone (0.46g, 1mmol) in THF (8ml) was added dropwise at -78 ° C. After stirring for 5 minutes, thyl acetate (1 ml) was added in one portion and the mixture was stirred for 3 hours at -78 ° C. The mixture was acidified with cold hydrochloric acid (0.5 n) to pH 6 and extracted with ethyl acetate (2 x 20 ml). The combined organic phases were dried and concentrated to give an oil (0.5 g) which crystallized from pentane: a total of 200 mg, 40%; mp.

122-124 ° C; ir vm: 1750, 1710 cm "1; 1 Hmr (CDCL) δ: 8-7.1 (15H, max., aromatic), 4.83 (1H, d, J = 2, H-4), 3.38 (1H, d, J = 2, H = 3), 1.80 (3H, s, CH 3), 0.92 (9H, s, Bu and 0.3 ppm (6H, s, CH 3)).

35

DK 161520 B

Preparation of trans-1- (t-butyldimethylsilyl) -3-formyl-4-tritylthio-2-azetidinone o 05 Sc

Li V σ * ~ V

To a cooled (-78 ° C) solution of diisopropylamine (0.34 mL, 2.4 mmol) in tetrahydro-uranium (5 mL) ), a solution of 1.5 m n-BuLi (1.6 ml, 2.4 mmol) was added, under stirring N2, after stirring for 30 minutes a solution of 1- (t-butyldimethylsilyl) -4- tritylthio-2-azetidinone (1.0 g, 2.18 mmol) in tetrahydro-uranium (5 ml), stirring was continued for 30 minutes, ethyl formate (0.8 ml, 9.9 mmol) was added and the cooled The reaction mixture was washed successively with cold 1N hydrochloric acid (5 ml), 1m sodium bicarbonate (6 ml), water (10 ml) and brine. The organic layer was dried (MgSO 4), evaporated and crystallized from 20 pentane to give 810 mg (76%) formate as a white solid, mp 132-133 ° C; ir (CHCl 3); ν max: 1760, 1715 cm -1; 1 Hmr (CDCl 3) 6: 9.0 (1H, d, J = 1.25 Hz), 7.30 (15H, m), 4.7 (1H, d, J = 1.5 Hz) and 3.5 ppm (1H, t, J = 1.5 Hz) ).

NOTE: a) diisopropylamine was distilled over CaH and

25 were stored on KOH

b) tetrahydro uranium was distilled over L.A.H. and stored on molecular sieves 3Å.

c) ethyl formate was stirred at room temperature with K 2 CO 3 and then distilled over P 2 And 30 d) n-BuLi was titrated with 1 n hydrochloric acid, E. Preparation of 1- (t-butyldimethylsilyl) -3- (1'-hydroxy-1'-ethyl) -4-tritylthio-2-azetidinones (4-isomeric) 35

DK 161520 B

44

OH

s ^ 3 oΑ-γ80 * 3 05 Λ, / - * ^ (Me) ^ (Me) 2 ^

V

10 n-Butyllithium (1.6 m, 3.4 mL, 5.44 mmol) was added over 5 minutes to a solution of diisopropylamine (0.847 mL, 6.23 mmol) in THF (30 mL) which was kept at -78 ° C. After 0.5 hour, a solution of 1- (t-butyldimethylsilyl) -4-tritylthio-2-azetidinone (2.0 g, 4.4 mmol) in THF (20 mL) was added; · after T5 minutes, acetaldehyde (10 ml) in one portion; after a further 15 minutes, water (100 ml) was added. The mixture was acidified (pH 5-6) with dilute hydrochloric acid and extracted with ethyl acetate (3 x 30 ml). The organic phases were washed with seeding water, dried and concentrated to give an oil which, by thin ag chromatography, was found to consist of four isomers (labeled isomers A, B, C, D in descending order of polarity).

Crystallization of the oily residue in ethyl acetate-pentane gave isomers B and C as a white solid, leaving A and D in the mother liquors. The four pure compounds were obtained by preparative chromatography (Waters, 500) of the above solid and mother liquids.

The relative ratios were: A 17%, B 32%, C 39%, D 12%. When in the above reaction, ether was substituted for THF and chilled after 1 minute at -78 ° C, the relative ratios of A, B, C and D were: 12.9; 30.5; 38.2 and 18.4%. In ether, the conditions when the reaction was allowed to reach 20 ° C for 2 hours before cooling were: 13.4; 24.6; 30 44 and 18%. Adding a mole equivalent of anhydrous magnesium bromide to the reaction mixture changed the ratio to: 19.2; 19.7; 30.1 and 31%.

Isomer A: This isomer has cis-stereochemistry at C3-C4. It is a racemic mixture consisting of the (1'S, 3R, 4R) and (1'R, 3S, 4S) enantiomers. Compounds which are subsequently derived from compound A are called "isomer A". They consist of an enantiomeric mixture and have the same

DK 161520 B

45 configuration at C1, C3 and C4. Compounds derived from compound A in a reaction inversion reaction will be called "isomer D" if the inversion occurs at C1 and "isomer C" if it occurs at C3; mp. 152-153 ° C; Δ: 8.0-6.8 (15H, m, aromatic), 4.30 (1H, d, J = 5.5, H-4), 3.78 (1H, m, H-1 '), 3.10 (1H, dd, J = 5.5, J = 10, H-3), 1.22 (3H, d, J = 6.5, CH 3), 0.95 ( 9H, s, Bu), 0.27 (6H, 2s, CHg).

Analysis calculated for: C 30 H 37 NO 2 Si: C 71.52; H, 7.40; N, 2.78; S, 6.36%. Found: C, 71.28; H, 7.41; N, 2.48; S, 6.19%.

Isomer B: This isomer has trans-stereochemistry at C3-C4. It is a racemic mixture of the (1'R, 3S, 4R) and 1'S, 3R, 4S) enantiomer. Compounds of the same configuration at C1, C3 and C4 are called 15 "isomer B"; ir (CHCl 3) ν max: 1745 cm 1 ((c = o); mp. 158-159 ° C; 1 Hmr (CDCl 3) δ: 7.60-7.10 (15H, m, aromatic), 4.02 (1H, d, J = 0.8 H-4), 3.32 (1H, dd, J = 3.0 , J = 0.8, H-3), 3.55-3.15 (1H, m, H-11) / 0.88 (12H, CH 3, and t-Bu), 0.16 (6H, s , CH3).

Isomer C: This isomer has trans-stereochemistry at C3-C4. It is a racemate formed by the (1'S, 3S, 4R) and (1'R, 3R, 4S) enantiomers. Compounds of the same configuration at C1, C3 and C4 are called "isomer C". Mp. 134-136 ° C; 1 Hmr (CDCl 3) δ: 7.60-7.10 (15H, m, aromatic), 4.32 (1H, d, J = 1.8, H-4), 3.02 (1H, dd, J = 2, 7, J = 1.8, H-3), 3.0-2.5 (1H, dq, J = 2.7, J = 6, H-1 '), 1.02 (3H, d, J = 6, CH 3), 0.95 (9H, s, t-Bu), 0.27 (6H, s, CH 2); ir (CHCL) νm: 1735 cm -1 (c = o).

Isomer D: This isomer has cis-stereochemistry at C3-C4. It is a racemate consisting of the (1'R, 3R, 4R) and (1'S, 3S, 4S) enantiomers.

Compounds of the same configuration at C1, C3 and C4 are called "isomer D". Mp. 171-172 ° C; Hmr (CDCl 3): 7.80-6.90 (15H, m, aromatic), 4.70 (1H, d, J = 4.5, H-4), 3.02 (1H, dd, J = 4 5, J = 0.5, H-3), 2.39 (1H, dq, J = 0.5, J = 6.5, H-1 '), 1.0 (3H, d, J = 6.5, CH 3), 0.97 (9H, s, t-Bu), 0.32 (6H, s, CH 3).

35

DK 161520 B

46

Analysis calculated for C C CH ^ yNO₂Si: C, 71.52; H, 7.40; N, 2.78; S, 6.36%

Found: C, 71.27; H, 7.43; N, 2.51; S, 6.31%.

05

OH

1i ^ scφ * _ At l ^ sc <f> 3 ^ N-f 3 BH -f ____ _________

b) I -4-> I

0 <L_S / Bu BuXMe 10 2 2 2 trans isomers A solution of trans-3-acetyl-1- (t-butyldimethylsilyl-4-tritylthio-2-azetidinone (1.0 g , 2 mmol) in THF (30 ml) was added dropwise, under nitrogen atmosphere, to a cooled (0 °) and stirred suspension of sodium borohydride (0.38 g, 10 mmol) in THF (120 ml). The ice bath was removed and the mixture was stirred. at room temperature for 4 hours.

It was poured into ice-cold hydrochloric acid (1 n, pH 6), stirred for 15 minutes and extracted with ether (3X). The combined ether extracts were dried and concentrated to give an oil (1.04 g) which crystallized in pentane to give the title compound as a 70:30 mixture of the C and B isomers. Mp. 119-121 ° C; 84%.

25

OH

Åi_ ^ C4,3 -TSCp3 c) I -> λ_n s? - 'N ^ & ^ SiiCH) ® ^ SUCHJ, 30 \ lCH3) 2 Vbu3 2 t-3u

Isomer B

A suspension of cuprous iodide (4.78 g, 15 mmol) in ether (50 ml) was cooled to 0 ° C and treated under a 1.9 m solution of methyl lithium (26 ml, 50 mmol). The brown solution was stirred at 0 ° C for 10 min. and then cooled to -60 ° C and treated

DK 161520 B

47 dropwise with trans-1-1- (t-butyldimethylsilyl) -3-formyl-4-tritylthio-2-azetidinone (2.43 g, 5.0 mmol) in a mixture of tetrahydro-uranium (10 ml) ether (40 ml). Stirring was continued for 3 hours. The solution was warmed to -40 ° C and carefully treated with a 1 m solution 05 of ammonium chloride. The mixture was filtered over Celite and the organic phase was washed with a 1 m solution of ammonium chloride (3 x 5 ml) and then brine and then dried over sodium sulfate. Filtration and evaporation gave alcohol, isomer B, which crystallized from hot pentane to give 1.6 g (65%), m.p. 160-161 ° C; ir (CHCl 3) 10: 1730 cm -1; 1 Hmr (CDCL) δ: 7.32 (15H, m), 4.05 (1H, s), 3.4 (1H, d, J = 3Hz, 3.25-3.55 (1H, m), 1 , 6 (1H, s), 0.9 (12H, s) and 0.1 ppm (6H, s).

Note: a) Tetrahydrofuran and ether were distilled over L.A.H.

B) methyl lithium was titrated with 1N hydrochloric acid; c) Copper (l) iodide was purified by continuous extraction with anhydrous tetrahydrofuran in a Soxhlet centrifuge for 18 hours and then dried under vacuum in a desiccator (P2 ° 5) for 18 hours.

20

o 0H

„-Yr * · _. <rt "'25 0 ^ -N-v.si'He2 / ~ N \ si'Me3 * tBu N tBu

Methylmagnesium iodide (0.1 ml, 0.1 mmol) was added dropwise to a cooled (0 ° C) and stirred solution of trans-1- (t-butyldimethylsilyl) -3-formyl-4-tritylthio-2-azetidinone ( 25 mg, 0.05 mmol) in THF (2 ml). The solution was stirred for 1.5 hours at 0 ° C, poured onto an ammonium chloride solution, acidified with a hydrochloric acid solution (1 n) and extracted with ether. Drying and concentration of the organic extracts left an oil consisting of starting material and a small amount of a mixture of the two trans-title compounds with isomer B as dominant.

DK 161520 B

43 F. Preparation of CTS, 3S, 4R- and TR, 3R, 4S-) 1- (t-Butyldimethylsilite) -3- (11-trimethylsilyloxy-11-ethyl) -4-tritylthio-2-azetidinone (isomer C) 05 OH OSi- • 'sA- 0 10 ^ x

A solution of (1'S, 3S, 4R- and 1'R, 3R, 4S-) 1- (t-butyldimethyl-silyl) -3 "(1, -hydroxy-1'-ethyl) -4-tritylthio-2- azetidinone (15 mg, 0.3 15 mmol) and azidotrimethylsilane (35 mg, 0.30 mmol) in dry THF (6 ml) were stirred at room temperature until no more of the starting material was left (15 min) · Purification of the reaction mixture by column chromatography (silica gel, CF ^C ^) gave the desired compound as a white solid (128 mg, 74%); mp. 144-146 ° C. Hmr (CDCl 3) δ: 7.10-7.60 (15H, m, aromatic), 4.30 (1H, d, J = 1.5, H-4), 2.25-2.89 ( 2H, m, H-3, H-1 '), 0.82-1.07 (12H, m, t-Bu, H-2'), 0.27 (6H, s, CH 3), -0, 10 (9H, s, -O-Si (CH 3) 3; ir (CHCl 3) v: 1736 cm 1 (c = o)).

G. Preparation of (1'S, 3R, 4R- and 1'R, 3S, 4S-) (1'C-butyldimethylsiphyl) -3- (T-methoxymethoxyether-1'-ethyl) -4-tritylthio-2-azetidone (isomer A).

30 AND OCH3 OH ^ / SCØ

. i

Π -i-N. / (Me) 2 ϋ ^ Si (Me) _ ^ t-Bu I 2 t-Bu

DK 161520 B

49 n-Butyllithium (about 12.5 ml of 1.6 m solution in hexane, 20 mmol, just enough to obtain a permanent pink stain) was added dropwise to a solution of (1'S, 3R, 4R and 1'R, 3S, 4S-) 1- (t-Butyl-dimethylsilyl) -3- (11-hydroxy-1'-ethyl) -4-tritylthio-2-azetidinone 05 (isomer A) (10.1 g, 20 mmol) in THF (100 ml) maintained at -78 °.

After 15 minutes of stirring, a solution of bromomethoxymethyl ether (2 ml, 24 mmol) in THF (30 ml) was added dropwise. The mixture was stirred for 1 hour at -78 ° and for 2 hours at room temperature and poured into an ammonium chloride solution (200 ml). Extraction with ethyl acetate 10 (3 x 200 ml), washing with brine, drying with sodium sulfate and concentration gave the crude title compound which was purified by chromatography on silica gel eluting with increasing amounts of ether in benzene (10.4 g, 95% ). Hmr (CDCl 3) δ: 7.1-7.5 (15H, m, aromatic), 4.47 (1H, d, H-4), 4.23 (2H, ABq, J = 7, 0- CH2-0), 3.1-3.4 (2H, 15 m, H-3 and HT), 3.23 (3H, s, O-CH3), 1.37 (3H, d, J = 6, 5, CH 3), 0.97 (9H, s, Bu) and 0.25 ppm (6H, 2s, CHg).

H. Preparation of (1'S, 3S, 4R and 1'R, 3R, 4S) 1- (t-butyldimethylsilyl) -3- (11-formyl-20-oxy-11-ethyl) -4-tritylthio-2- azetidinone (isomer C) A solution of (1'S, 3S, 4R and 1'R, 3R, 4S) 1- (t-butyldimethylsilyl) -3- (1'-hydroxy-1, ethyl) -4- tritylthio-2-azetidinone (isomer C) (50 mg, 0.1 mmol), p-bromobenzenesuffonyl chloride (100 mg, 0.4 mmol) and dimethylaminopyridine (24 mg, 0.2 mmol) in DMF (3 ml) was stirred at room temperature until the starting material had disappeared (0.5 35 hours). Then, the reaction mixture was diluted with water and extracted with ether. The organic extracts were washed with brine, dried (MgSC> 4) and evaporated. The title compound was purified

DK 161520B

50 by column chromatography. Hmr (CDCl 3) δ: 7.80 (1H, s, CHO), 7.20--7.66 (15H, m, aromatic), 3.90-4.36 (1H, m, H-11 ), 4.07 (1H, d, J = 2, H-4), 3.22 (1H, broad s, H-3), 1.18 (3H, d, J = 6.5, H-2) ), 1.0 (9H, s, t-Bu), 0.31 (6H, s, di-CH 3).

05 I. Preparation of (1'R, 3S, 4R and VS, 3R, 45) 1'Ct-butyldimethylsilyQ-S-1'-acetoxy-1 * -ethyl) -4-trimethylthio-2-azetidinone (isomer B) 10 OAc PH I JSTr _ / STr Ae 2 ° '"'" l-1 J_N / Pyridine * J-χ 15

A solution of (1'R, 3S, 4S and 1'S 3R 4S) 1- (t-butyldimethylsilyl) - S-O-hydroxy-1'-ethyl) -4-tritylthio-2-azetidinone (13.85 g (27.5 mmol) in pyridine (75 ml) acetic anhydride (50 ml) (prepared at 0 °) was stirred at room temperature for 40 hours. The reagents were evaporated (the last traces azeotropically removed with toluene 3 times) leaving an almost white solid. Crude crystal derivative was lasered from an ether-petroleum-ether mixture to give pure title compound (97.5%). Hmr (CDCl3 6: 7.64-7.03 (15H, m, H aromatic), 4.60 (1H, m, J = 6, H-1 '), 3.92 (1H, d, J = 2, H-4), 3.55 (1H, dd, J = 2, J = 6, H-3), 1.79 (3H, s, CH 3 CO), 0.98 (3H, d, J = 6 , CH 3) 0; 88- (9H, s, t-butyl), 0.12 (6H, s, CH 3); ir (CHCl 3 max: 1775, 1740 cm -1 (C = O) 1- (t-Butyldimethylsilyl) -3- (1'-paranitrobenzyldioxycarbonyl) -1ethyl) -4-tritylthio-2-azetidinone (4 isomers)

DK 161520 B

51

PH, QCO PNB

__. ^ rrsc ^ 05 <f— \ Λ / „V./'i

Si

NtBu NtBu "Isomer C11 n-Butyllithium (8.8 ml of 1.6 m solution in hexane, 14 10 mmol, just enough to obtain a permanent pink stain) was added dropwise to a solution of" Isomer C "of 1- (t -butyldimethyl-silyl) -3- (1'-hydroxy-11-ethyl) -4-tritylthio-2-azetidinone (6.55 g, 13 mmol) in THF (70 ml), maintained at -78 ° C. After stirring for 15 minutes, a solution of paranitrobenzyl, chloroformate 15 (3.2 g, 14.8 mmol) in THF (30 ml) was added dropwise, the mixture was stirred for 1 hour at -78 ° C and poured into an ammonium chloride solution (100 mL). Extraction with ethyl acetate (3 x 100 ml), washing with brine, drying and concentration gave 11 g of crude material. The pure title compound was obtained by chromatography on silica gel (220 g) eluting with 20 increasing amounts of ether in benzene. 93%, m.p. 118-119 ° C (ether); 1 Hmr (CDCl 3) 6: 8.35-7 (19H, m, aromatic), 5.12 (2H, s, benzyl), 4.08 (1H, d, J = 1.8, H-4), 4 -3.5 (1H, dq, J = 6.5, J = 2, H-1 '), 3.10 (1H, dd, J = 2, J = 1.8, H-3), 1, 2 (3H, d, J = 6.5, CH 3), 1.0 (9H, s,

Bu) and 0.30 ppm (6H, 2s, CH-); ir (CHCL v: 1745 cm -1) (C = O); Analysis calculated for C38H42N2 ° 6S1S: C, 66.83; H, 6.20; N, 4.10; S, 4.69;

Found: C, 66.90; H, 6.26; N, 4.11; S, 4.59.

"Isomer B" "Isomer B" of 1-it-butyldimethylsilyO-5-O-hydroxy-1,130-ethyl (-4-tritylthio-2-azetidinone gave by treatment as described above pure "isomer B" of 1- (t-butyldimethylsilyl) -3- (1'-paranitrobenzyldioxycarbonyl-1'-ethyl) -4-tritylthio-2-azetidinone in the form of a foam, 95% 1 Hmr (CDCl 3) δ: 8.32-6, 90 (19H, m, aromatic), 5.1 (2H, s, benzyl), 4.65-4.20 (1H, m, H-1 '), 3.97 (1H, d, J = 1, 5, H-4), 3.58 (1H, dd, J = 1.5, J = 5.8, H-3), 1.1 (3H, d, CH 3), 0.7 (9H, s,

Bu and 0.2 ppm (6H, s, CH.,); ir (film) v: 1755, 1740 cm -1 C = 0.

j msx

DK 161520B

52 "Isomer A11" Isomer A "of 1-Ct-butyldimethylsilyl-5-O-hydroxy-11-ethyl) -4-tritylthio-2-azetidinone gave by treatment as described above pure" Isomer A "of 1 - ( t-Butyldimethylsilyl-paranitro-benzyldioxycarbonyl-1'-ethyl) -4-tritylthio-2-azetidinone in the form of an oil 95% ^ Hmr (CDCl 3) δ: 8.3-6.7 (19H, m, aromatic ), 4.95 (2H, ABq, benzyl), 4.53 (1H, p, J = 7.5, 4.31 (1H, d, J = 6, H-4), 3.32 (1H, dd, J = 6, J = 7.5, H-3), 1.44 (3H, d, J = 6.5), 0.95 (9H, s, tBu) and 0.2 ppm (6H, 2s, CH 2).

"Isomer D" Similarly, "Isomer D" of 1- (t-butyldimethylsilyl-3- (11-hydroxy-1'-ethyl-4-tritylthio-2-azetidinone) gave "Isomer D" of 1- (t -butyldirnethylsilyl) -3- (1'-paranitrobenzyldioxycarbonyl-1'-ethyl) -4-tritylthio-2-azetidinone, 90%. ** Hmr (CDCl3) δ: 8.3-6.7 (19H, m , aromatic), 5.20 (2H, ABq, benzyl), 4.72 (1H, d, J = 5, H-4), 3.50 (1H, dq, J = 6.5, J = 0 , 5, H-1 '), 2.85 (1H, dd, J = 0.5, J = 5, H-3), 1.03' (3H, d, J = 6.5, CH 3), 1.0 (9H, s, t-Bu) and 0.35 ppm (6H, s, CH 3); mp 130-132 ° C-

Analysis calculated for C38H42N2 ° 6SiS: C, 66.83; H, 6.26; N, 4.10; S, 4.70; Found: c, 66.56; H, 6.28; N, 3.96; S, 4.89.

K. Preparation of (1'S, 3S, 4R and 1 * R, 3R, 4S) T- (t-Butyldimethylsilyl) -3- (1'-methanesulfonyl dioxyl-11-ethyl) -4-tritylthio-2-azetidinone ( Isomer C) 25 oh 0Ms Χγ **, A ^ c „3.2

Vbu t-Bu

A solution of (1'S, 3S, 4R and 1'R, 3R, 4S) -1- (t-butyldimethyl-.

Silyl) -3 - ((1'-hydroxy-11-ethyl) -4-tritylthio-2-azetidinone (Isomer C) (2.0 g, 4 mmoj) in dichloromethane (80 ml) was treated at 5 ° C with methanesulfonyl chloride (0.99 g, 8.6 mmol) and triethylamine (0.87 g,

DK 161520 B

53 8.6 mmol). After stirring at this temperature for 1 hour, the solution was washed with brine, dried (MgSO 4) and evaporated to dryness. After crystallization from ether-petroleum ether, 1.9 g (81.9%) of mesylate is obtained. Mp. 120-122 ° C; 1 Hmr (CDCl 3) 6: 7.13-7.61 05 (15H, m, aromatic), 4.50 (1H, d, J = 2, H-4), 3.62 (1H, dq, J = 6 , 5, 2, H-1 ') / 2.96 (1H, dd, J = 2, 2, H-3), 2.84 (3H, s, methanesulfonyl), 1.22 (3H, d, J = 6.5, H-2 '), 0.99 (9H, s, Si-t-Bu) and 0.30 ppm (6H, s, Si- (CHo) 9); ir (CHCL): 1746 (C = O), 1343 and 1180 cm -1 (SO 2).

10 L. Preparation of (VR, 3S, 4R and TS, 3R, 4S) 1- (t-Butyldimethylsilyl) -3- (1'-methanesulfonyloxy-11-ethyl) -4-tritylthio-2-azetidinone (Isomer B) 15

OH MsO

Α-γΕΦ3 20 \ x

A solution of (1'R, 3S, 4R and 1'S, 3R, 4S) 1- (t-butyl dimethylsilyl) -3- (1'-hydroxy-11-ethyl) -4-tritylthio-2-azetidinone (Isomer B) (5.03 g, 10 mmol), methanesulfonyl chloride (2.52 g, 22.0 mmol) and triethylamine (2.23 g, 22.0 mmol) in CH at 5 ° C for 1 hour. Then, the solution was washed with brine, dried (MgSO 4) and evaporated to give a residue which crystallized as a white solid by trituration in ether (5.40 g, 93%). 127-131 ° C. 1 Hmr (CDCl 3) 6: 7.20-7.63 (15H, m, aromatic), 4.51 (1H, dq, J = 5.0-6.2, H-1 '), 4.10 (1H , d, J = 2.0, H-4), 3.60 (1H, dd, J = 5.0-2.0, H-3), 2.03 (3H, s, -CHg), 1 , 01 (3H, d, J = 6.2, H-2 '), 0.90 (9H, s, t-Bu), 0.12 (6H, s, -CH 3); ir (CHCl 3) νm): 1745 cm cm "(C = 0).

35

DK 161520 B

54 M. Preparation of (1IS / 3S / -4R and 1'R, 3R, 4S) 3- (1R-p-bromobenzene sulfonyloxy-V-ethyl) -1- (t-butyl dimethylsilyl) -4-tritylthio-2 -azetidinone (Isomer C) 05 OH oso φΒτ 10 \ \

A solution of (1'S / 3S / 4R and TR / SR3S) 1- (t-butyldimethylsilyl) -3- (T, hydroxy-1'-ethyl) -4 "tritylthio-2-azetidinone (isomer C) 15 (2.5 g, 5 mmol) in dry THF (100 ml) was cooled to -78 ° C and treated with 2.52 m butyllithium / hexane (2.38 ml, 6 mmol). After 3-4 minutes, p-bromobenzene sulfonyl chloride (1.53 g, 6 mmol) dissolved in THF was added dropwise. The solution was stirred at -78 ° C for 3 hours and then allowed to come to room temperature. Then, the solvent was evaporated and the desired product was purified by column chromatography (silica gel, CH2 Ig) (3.36 g, 94.6%) m.p.

142-144 ° C; Hmr (CDCl 3) 6: 7.68 (4H, s, benzenesulfonyl), 7.28-7.60 815H, m, aromatic), 4.59 (1H, d, J = 1.8, H-4 ), 3.68 (1H, dq, J = 6.2, H-1 '), 2.99 (1H, dd, J = 1.8, 2.0, H-3), 1.18 (3H , d, J = 6.2, H-2 '), 1.08 (9H, s, t-Bu), 0.40 and 0.38 (6H, 2S, -CH 3); ir (CHCl 3) νm: 1749 cm "1 (C = O). max N. Preparation of (1 * S, 3R, 4R and 1 (R, 3S, 4S) 3- (11-methoxymethyl-1'-ethyl) - 4-30 trithylthio-2-azetidinone (isomer A) OCH2OCH3 OCH5OCH-3

Ap », __ K-f * '35" ^ ΝνΉ t-Bu

DK 161520 B

55

A cold (0 ° C) HMPA-100 (116 ml-13 ml) solution of isomer A of 1- (t-butyldimethylsilyl) -3- (1, -methoxymethyl-1, ethyl) -4-tritylthio -2-azetidinone (11 g, 20 mmol) was treated with sodium azide (2.7 g, 42 mmol). The cold bath was removed and the mixture was stirred for 30 minutes. It was then poured into cold water (1.3 liters) and dried. The title compound recrystallized from ethyl acetate-hexanes (7.2 g, 83%) as a white solid, m.p. 173-174 ° C.

Hmr (CDCl3) δ: 7.10-7. (15H, m, aromatic), 4.85 (2H, ABq, J = 7.4, 0-CH 2 -O), 4.53 (1H, d, J = 5.2, H-4), 4, 42 (1H, s, NH), 4.15 (1H, m, H-1 ') / 3.5 (1H, m, H-3), 3.47 (3H, s, O-CH 3). ir (KBr): 3400-3500 (N-H) and 1760 cm -1 (C = 0).

M3X

O. Preparation of (1 * S, 3S, 4R and 1 * R, 3R, 4S) 3- (11-Methoxymethyloxy-11-ethyl) -15 4-tritylthio-2-azetidinone (Isomer C) OH and 2 and 3 and 2 and 3 X STr A, ^ STr X, STr r * ··.-S BrCH2OCH3 '\ - | A cold (dry ice-acetone bath) solution of (1'S, 3S, 4R and 1'R, 3R, 4S) 1- (t-butyldimethylsilyl) -3- (1'-hydroxy) 1'-Ethyl) -4-trityl-thio-2-azetidinone (5.03 g, 10 mmol) in THF (50 ml), distilled over LAH) was treated dropwise with a 1.6 m solution of n-butyllithium in hexane (13.0 ml) until a persistent pink color was obtained.

A THF (20 ml) solution of bromomethyl methyl ether (1.49 g, 0.97 ml, 1.19 mmol) was added dropwise. The mixture was stirred at -78 ° C for 30 minutes and for 3 hours at 0 ° C. It was poured into an ice-cold ammonium chloride solution and extracted with ether. The ether extracts were combined, washed with water, dried (MgSO 4) and concentrated to give crude (1'S, 3S, 4R and 1'R, 3R, 4S) 1- (t-butyldimethylsilyl) -3- (V-methoxymethyloxy) (1-ethyl) -4-tritylthio-2-azetidinone (5.83 g, 100%) which was deprotected as described below:

DK 161520 B

56

A koid (ice-bath) solution of the above derivative (5.83 g, 10 mmol) in HMPA-t (90 ml-10 ml) was treated with sodium azide (1.365 g, 21 mmol). The cooling bath was removed and the mixture was stirred at room temperature for 2 hours. It was then slowly poured into ice-cold water 05 (900 ml) and stirred for 30 minutes. The precipitate was collected by filtration and redissolved in methylene chloride. The solution was washed with water and brine and dried (MgSO 4) to give the title compound (3.0 g, 69.3%), m.p. 172-172.5 ° C (ethyl acetate-hexane); ir (CHCL) v: 3400 (NH) and 1760 cm "1 (C = O) 1 Hmr (CDCL) δ: 10 7.67-7.12 (15H, m, H aromatic), 4.63 (2H, center of ABq, J = 6.0-CH 2 -O), 4.49 (1H, s, NH), 4.40 (1H, d, J = 3, H-4>, 4.25-3.80 ( 1H, m, H-11) / 3.35-3.15 and 3.26 (4H, s + m, GHg and H-3) and 1.30 ppm (3H, d, J = 6, CH 3).

15 p. Preparation of (1JR, 3S, 4R and 1'S, 3R, 4S) · 3 * - (1'-Formyloxy-1'-ethyl) -4-tritylthio-2-azetidinone (Isomer B)

20 OSO φΒΓ OCHO

a2_> v Χ ^ -φ3.

25

A solution of (1'S, 3S, 4R and 1'R, 3Rt4S) 3- (1'-p-bromobenzene-sulfonyloxy-11-ethyl) -1- (t-butyldimethylsily] -4-tritylthio-2-azetidinone (isomer) C) in DMF (3 ml) is heated at 50 ° C for 48 hours and then 30 at 100 ° C for 4 hours. The reaction mixture was then diluted with H 2 O and extracted with ether. The ethereal extracts were washed with brine, dried. (MgSO 4) and evaporated. The title compound was obtained as white crystals after purification by column chromatography (silica gel, 5% CH 3 CN-CH 2 C [2) (2 mg, 4.8%), m.p. 131-132 ° C; 1 Hmr 35 (CDCl 3) δ: 8.07 (1H, s, CHO), 7.24-7.56 (15H, m, aromatic), 5.23 (1H, dq, J = 6.4, 7, HT ), 4.38 (1H, dm J = 2.4, H-4), 4.25 (1H, s, NH), 3.20 (1H, dd, J = 7, 2.4, H-3) ), 1.43 (3Ή, d, J = 6.4, H-2 '); ir (CHCL) v: 3400 (NH), 1765 (C = 0), 1725 cm -1 (C = 0).

O ΓΠ9Χ

DK 161520 B

57 Q. Preparation of (1'R, 3S, 4R and TS, 3R, 4S) 3- (V-acetoxy-1'-ethyl) -4-tritylthio-2- 2-azetidinone (isomer B) OAc OAc - rSTr NaN3 Λ- ^ STr - oJ- »

Pure Derivative (TR, 3S, 4R and 1'S, 3R, 4S) 1- (t-Butyldimethylsilyl) - 3- (1'-acetoxy-1'-ethyl) -4-tritylthio-2-azetidinone (5.77 g (10.57 mmol) was dissolved in warm HMPT water (60 mL, 10 mL). The solution was cooled to room temperature and NaN 2 (1/2 g) was added. It was stirred for 45 minutes (the reaction was followed by thin layer chromatography) and poured slowly into stirred cold water (800 ml). The mixture was stirred for an additional 20 minutes. The crystalline material was collected and washed with water. It was redissolved in Ch 2 C 2, washed with water (twice) and brine and dried over MgSO 4. Solvent evaporation left a foam which crystallized from ether-petroleum ether (4.90 g, 96.5%, mp 143-144.5 ° C).

Δ (CH 2 Cl 2) ν max: 3395 (N-H), 1772, 1738 crrf1 (C = 0). 1 Hmr (CDCl 3) 6: 7.9-6.8 (15H, m, H aromatic), 5.12 (1H, center of dq, J = 6.5, 7.5, H-1 '), 4, 33 (1H, d, J = 2.8r H-4), 4.20 (1H, bs, NH), 3.17 (1H, ddd, 2, = 7.5, J3_4 = 2.8, J3_NH = 1, H-3), 2.1 (3H, s, CH 3 CO), 1.35 (3H, d, J-6.5, CH 3).

Preparation of 3- (1'-Hydroxy-1'-ethyl) -4-tritylthio-2-azetidinone. Blend of four isomers). .; j 05 'OAc, Ιλ * ·, «-Vf' I - ^“ * 3. CH3 1 Γ: pyridine '] _tl

in ΓΠ CH3CHO eye— ^ · ° H

10 ° Si (CH 3> 3 ·, J-Si-Cl - [3 Li -► ΊΖ 1, DMF-N (Et) 3 CT 2 Si 4 - -] A solution of lithium diisopropylamide (0.74 mmol) was prepared by -78 ° C in dry tetrahydro-uranium (5 ml) from diisopropylamine (0.103 ml, 0.74 mmol) and BuLi (0.29 ml of a 2.52 m solution in hexane).

After 30 minutes at -78 ° C, a solution of (R and S) 1-trimethylsilyl-4-tritylthio-2-azetidinone (0.292 g, 6.99 mmol) 20 in dry tetrahydrofuran (2 ml) was added three times. After 5 minutes, excess fresh distilled acetaldehyde (0.2 mT) was added at once. After 20 minutes at -78 ° C, thin ag chromatography showed complete decay of starting materials and the reaction mixture quenched by addition to a saturated solution of ammonium chloride. Extraction with ethyl 25 acetate (2 x 25 ml) followed by washing the combined organic phases with saturated NH 4 Cl, brine and drying in anhydrous magnesium sulfate gave a yellow oil after evaporation of the solvent. Filtration of this oil on silica gel (10 g, elution CgHgiEtOAc, 6: 4) gave a mixture of the alcohols (0.215 g, 80%). This mixture (1 Hmr) cannot be separated either by HPLC or by TLC.

a: Acetylation

Acetylation of a portion of the mixture (0.065 g) with excess acetic anhydride (1.0 ml) and pyridine (1.4 ml) gave a mixture of acetates. HPLC analysis revealed four components: a) 34.6%; b) 17.4%; c) 30.1%; d) 17.9%. Compound a) was identical to isomer 4 B by direct comparison (HPLC).

DK 161520 B

53 b: t-Butyldimethylsilyl derivatives

The mixture of alcohols (0.121 g, 0.34 mmol) was treated with t-butyldimethylchlorosilane (0.117 g, 0.776 mmol) and triethylamine 05 (0.10 ml, 7.14 mmol) in dry dimethylformamide (1 ml) for 36 hours at room temperature. . After dilution with ethyl acetate, the solution was washed with saturated ammonium chloride and dried over anhydrous magnesium sulfate. Evaporation gave an oil (0.716 g) containing four components by HPLC. a = 3.7%; b = 60.6%; c = 31.1%; d = 4.6% 10 (the identity of each is not ascertained) ^ NOTE:

Butyllithium and lithium hexamethyldisilazane were ineffective.

2 15 Order of increasing polarity.

3

Acetylation of the product derived from 1-t-butyldimethylsilyl-4-tritylthio-2-azetidinone gave the following ratio: d = 29.5%; c = 24.1%; b = 33.8%; a = 12.6%.

Reaction of a mixture of alcohols derived from (R and S) 20 1- (t-Butyldimethylsyl) -4-tritylthio-2-azetidinone gave the following ratio: a = 5.2%; b = 41.3%; c = 48%; d = 4.6%.

25 S. Preparation of (1'R, 3S, 4R and 1'S, 3R, 4S) S-Q'-Benzoxy-1'-ethyl) -4-tritylthio-2-azetidinone (isomer B)

MsO ΟΟΟφ

V "1 _." VP

35

DK 161520B

60 j i

A solution of (1'S, 3S, 4R and 1'R, 3R, 4S) 3- (1'-methanesulfonyl-oxy-1'-ethyl) -4-tritylthio-2-azetidinone (isomer C) (035 mg, 2 mmol) and sodium benzoate (432 mg, 3 mmol) in 10% H 2 O-DMF (10 ml) are heated at 90 ° G for 7.5 hours. Then, the reaming mixture was diluted with 05 H 2 O and extracted with ethyl acetate. The organic extracts were washed with brine, dried (MgSO 4) and evaporated. The residue, after purification by column chromatography (silica gel, 5% CH 2 CN-Ch 2 Cl 2) gave the title compound as a white solid (108 mg, 23.2%), m.p. 158 ° C. THmr (CDCl 3) 6: 7.03-8.25 (20H, m, aromatic), 5.32 (1H, dq, J = 6.1, 9, H-1 '), 4.40 ( 1H, d, J = 2.5, H-4), 4.30 (1H, s, NH), 3.40 (1H, dd, J = 9, 2.5, H-3), 1.50 (3H, d,] J = 6.1, H-2 '); ir (CHCL) vm: 3400 (N-H), 1765 (C-O), 1715 cm “1 j O ΓΠαΧ |

(C = O). IN

T. Preparation of 3- (11-Paranitrobenzyldioxycarbonyl-11-ethyl) -4-tritylthio-2-azetidinone (4 isomers) µg 1 µg OCO PNB 9CO2pnb ^ tBu | "Isomer C11 a) A solution of" Isomer C "of 1- (t-butyldimethylsilyl) -3- (1'-paranitrobenzyldioxycarbonyl-1'-ethyl) -4-tritylthio-2-azetidinone (1.3 g) in a mixture of TFA (5 ml), water (5 ml), dichloromethane 30 (20 ml) and methanol (30 ml) was stirred for 2 days at room temperature.

The solution was diluted with water and the aqueous phase was extracted with dichloromethane. The combined organic phases were washed with sodium bicarbonate and water, dried and concentrated to give an oil. Crystallization from ether gave the pure title compound (902 mg), m.p. 78-80 ° C; Hmr (CDCl 3): 8.25-6.75 (19H, m, aromatic), 5.21 (2H, s, benzyl), 5.05 (1H, m, H-11), 4.40 (1H , s, NH), 4.27 (1H, d, J = 2.8, H-4), 3.37 (1H, dd, J = 5.3, 2.8, H-3)

DK 161520 B

61 and 1.37 ppm (3H, d, J = 6.5, CH 2); ir (CHCL) · 3390 (N-H), o -ο ΓΠαΧ 1765 and 1745 (shoulder) (C = 0), and 1525 cm "‘ (NOg).

b) A cold (0 ° C) HMPT-H2O (90 ml - 19 ml) solution of 05 "Isomer C" of 1- (t-butyldimethylsylyl) -3- (1'-paranitrobenzyldioxycarboxyl-11-ethyl ) -4-Tritylthio-2-azetidinone (9.11 g, 13.3 mmol) was treated with sodium azide (1.82 g, 27.9 mmol). The cold bath was removed and the mixture was stirred for 30 minutes. It was then poured into water (1 liter) and extracted with ether (5 x 200 ml).

The ether fractions were combined and washed with water (5 x 200 ml), brine and dried over IVIgSO4. Alternatively, as the title compound precipitated by dilution with water, it was filtered off and recrystallized from ether; 7.22 g, 89%, m.p. 78-80 ° C.

"Isomer B" "Isomer B" of 3- (1'-paranitrobenzyldioxycarbonyl-1'-ethyl) -4-tritylthio-2-azetidinone was prepared as described above for "Isomer C"; 92%; mp. 155.5-156 ° C (ether); 1 Hmr (CDCl 3) 6: 8.25-6.80 (19H, m, aromatic), 5.20 (2H, s, benzyl), 4.95 (1H, 20 m, H-11), 4.35 ( 1H, d, J = 2.9, H-4), 4.17 (1H, s, NH), 3.20 (1H, dd, J = 10.8, J = 2.9, H-3) and 1.40 ppm (3H, d, J = 7.5, (CH 2); ir (CHCL) v · 3480, 3390 (NH), 1772, 1750 (C = O) and 1525 cm -1

<3 maX

(NO2).

Analysis calculated for C 32 H 28 N 2 O 6 S: 25 C, 67.59; H, 4.96; N, 4.93; S, 5.64;

Found: C, 67.48; H, 4.98; N, 4.92; S, 5.67.

"Isomer A" "Isomer A" of 3- (1'-paranitrobenzyldioxycarbonyl-1'-ethyl) -4-30-tritylthio-2-azetidinone was prepared as described above for "Isomer C"; mp. 205-206 ° C. 1 Hmr (CDClip 6: 8.2-6.7 (19H, m, aromatic), 5.22 (2H, ABq, benzyl), 5.57-4.85 (1H, m, H-11), 4, 65 (1H, NH), 4.50 (1H, d, J = 6.5, H-4), 3.65 (1H, dd, J = 6.5, 12, JN-hf1 'H "3 09 1/52 ppm (3H 'd / J = 7'5) · B [62] Isomer D11 "Isomer D" of 3- (1'-paranitrobenzyldioxycarbonyl-1'-ethyl) -4- tritylthio-2-azetidinone was prepared as described above for "Isomer

C 11 Hmr (CDCl 3) δ: 8.15-6.70 (19H, m, aromatic), 5.23 (2H, I

05 ABq, benzyl), 5.20 (1H, m, H-1 '), 4.75 (1H, NH), 4.52 (1H, d, <J = 5.5, H-4), 3 , 42 (1H, J = 5.5, 3, H-3, and 1.5 ppm (3H, d, J = 6.5, CH 2). (J value for H-3 taken after DgO yield).

U. Preparation of 10 (1 * R, 3S, 4R and 1'S, 3R, 4S) 3- (11-Ethanesulfonyloxy-1'-ethyl) -4-

methylthio-2-azetidinone (isomer B) I

j

MsO Ms (j> i 15 -Λ | 'i \ - j 35 20:

A solution of (1 ^, 33.4 (¾ and 1'S, 3R, 4S) 1- (t-butyldimethylsilyO-S-Cl'-methanesulfonyloxy-1'-ethylO ^ -tritylthio-E-azetidinone).

(Isomer B) (4.95 g, 8.5 mmol) and sodium azide (1.11 g, 17.0 mmol) in 10% H 2 O-HMPA (50 mL) was stirred at room temperature for 30 minutes.

Then the solution was diluted with water (250 ml) and extracted with ether. The organic extracts were washed with brine, dried, dried. (IVIgSO4) and evaporated. Crystallization of the residue (ether-petroleum ether) afforded the title compound (3.33 g, 83.8%). Mp. 130-131 ° C.

1 Hmr (CDCl 3) δ: 7.20-7.62 (15H, m, aromatic), 4.97 (1H, dq, 30 J = 6.4, 6.1, Η-11), 4.56 (1H , d, J = 2.8, H-4), 4.22 (1H, m, NH), 3.27 (1H, dd, J = 6.1, 2.8, H-3), 3, O (3H, s, -CH 3), 1.63 (3H, d, J = 6.4, H-2 '); ir (nujol) νm: 3195 (n-H), 1768 cm "1 (C = 0).

DK 161520 B

63 V. Preparation of (1 'S, 3S, 4R and 11R, 3R, 4S) 3- (11-Ethanesulfonyloxy-11-ethyl) -4-tritylthio-2-azetidinone (Isomer C) ° "Ni 10 t-Bu

A solution of (1'S, 3S, 4R and 1'R, 3R, 4S) 1- (t-butyldimethylsilyl) -3- (1'-methanesulfonyloxy-1'-ethyl) -4-tritylthio-2-azetidinone (isomer 15) C) (2.85 g; 4.9 mmol) in 10% aqueous HMPA (25 ml) was treated with sodium azide (0.65 g, 10 mmol) and stirred at 25 ° C for 0.5 hour. By diluting the solution with water (250 ml), the reaction product was forced to crystallize. The residual mesylate was redissolved in dichloromethane, washed with brine, dried (MgSO4) and evaporated.

Trituration in ether gave the title compound as white crystals, m.p.

155-160 ° C; 1.80 g; 78.6%; 1 Hmr (CDCl 3) δ: 7.43 (15H, m, aromatic), 5.02 (1H, dq, J = 6.9, 4.9, H-1 '), 4.55 (1H, s, NH ), 4.95 (1H, d, J = 3, H-4), 3.33 (1H, dd, J = 4.9, 3, H-3), 1.51 (3H, d, J = 6.9, H-2 '); ir v: 3395 (N-H), 1768 cm -1 (C = O);

UlaX

Analysis calculated for C 25 H 25 C 4 S: C, 64.22; H, 5.39; N, 3.00;

Found: C, 63.93; H, 5.39; N, 3.24%.

W. Preparation of 30 (1'S, 3S, 4R and 1'R, 3R, 4S) S-Q'-p-bromobenzenesulfonyloxy-11-ethyl) -4-tritylthio-2-azetidinone (Isomer C) oso Φβγ οεο2φΒΓ ^ - "Γ Η 64 ·

DK 161520 B

A solution of (1'S, 3S, 4R and 1'R / 3R, 4S) 3- (1'-p-bromobenzene sulfoxyloxy-1'-ethyl) -1- (t-butyl dimethylsilyl) -4-tritylthio-2- azetidinone (isomer C) (1.42 g, 2 mmol) and sodium benzoate (0.865 g, 6 mmol) in (10% HpO-HMPA (40 ml)) was stirred at room temperature for 1 hour. O (100 ml) and extracted with ether. The ether extracts were washed with brine, dried (MgSO 4) and evaporated. The crude crystalline title compound was triturated in a small volume of ether and collected by filtration (0.92 g, 77%). mp 125-126 ° C 1 Hmr (CDCl 3) δ: 7.80 (4H, s, benzenesulfonyl), 7.30-7.65 (15H, m, aromatic), 5.13 (1H, dq , J = 6.5, 4.0, H-11), 4.50 (1H, d, J = 2.9, H-4), 4.40 (1H, s, NH), 3.40 ( 1H, dd, J = 4.0, 2.9, H-3), 1.50 (3H, d, J = 6.5, H-2 '); ir (CHCl 3) v: 3400 cm NH), 1770 cm -1 (C = 0).

XαΧ 15 X. Preparation of (1'R, 3S, 4R and TS, 3R, 4S) 3- (11'-hydroxy-11-ethyl) -4-tritylthio-2-azetidinone (Isomer B)

OSO ^ Br 9H

J-N / * J-N.

0 ^ Si_U O. ^

V

25

To a warm solution of (1'S, 3S, 4R and 1'R, 3R, 4S) 3- (1'-p-bromo-benzenesulfonyloxy-1'-ethyl) -1- (t-butyldimethylsilyl) -4-tritylthio 2 - Azetidinone (isomer C) in HMPA (5 mL) was added dropwise 1 mL H 2 O.

The reaction mixture was maintained at 90 ° C for 20 hours, then diluted with ether and washed 4 times with brine. The organic solution was dried (MgSO 4), evaporated and the crude title compound was purified by column chromatography (silica gel, 15% CH 2 CN-C 2 C 2). A white solid (122 mg, 44.5%) was obtained, m.p. 187-189 ° C, which was found to be identical to a sample of the title compound prepared by another method.

DK 161520 B

65 Y. Preparation of 3- (1'-hydroxy-1'-ethyl) -4-tritylthio-2-azetidinone 05

OH 9H

> γγ5 <: φ3 _ (10

Both isomers, (1'S, 3S, 4R and 1'R, 3R, 4S) 3- (1'-hydroxy-1'-ethyl) -4-tritylthio-2-azetidinone (isomer C) and (1'R, 3S, 4R and 1'S, 3R, 4S) 3 '(1'-hydroxy-1, -ethyl) -4-tritylthio-2-azetidinone (isomer 15 B) was prepared by the same procedure. Eg. stirred a solution of (1'S, 3S, 4R and 1'R, 3R, 4S) 1- (t-butyldimethylsilyl) -3- (1'-hydroxy-1'-ethyl) -4-tritylthio-2-azetidinone ( isomer C) (1.0 g, 2 mmol) and sodium benzoate (0.865 g, 6 mmol) in 10% H 2 O -DMF (40 ml) at room temperature for 18 hours. Then, the reaction mixture was diluted with and extracted with ether. The organic extracts were washed with brine, dried (MgSC> 4) and evaporated. The crude title compound was crystallized from cold ether (0.47 g, 61%), m.p. 134-135 ° C. 1 Hmr (CDCl 3) 6: 7.12-7.56 (15H, m, aromatic), 4.48 (1H, s, NH), 4.28 (1H, d, J = 2.8, H-4) , 2.94 (1H, dq, J = 6.5, 6.2, 25 Η-11) / 3.06 (1H, dd, J = 6.2, 2.8, H-3), 2, 18 (1H, s, -OH), 1.30 (3H, d, J = 6.5, H-2 '); ir (CHCL) vm: 3400 (n-H), 1760 cm -1

ό filaX

(C = 0).

Similarly (1'R, 3S, 4R and 1'S, 3R, 4S) 1- (t-butyldimethylsilyl) -3- (1'-hydroxy-1'-ethyl) -4-tritylthio-2-azetidinone (isomer) B), m.p.

190-192 ° C. Hmr (CDCl 3) δ: 7.10-7.55 (15H, m, aromatic), 4.45 (1H, d, J = 2.5, H-4), 4.28 (1H, s, NH), 4.10 (1H, dq, J = 6.4, 5.3, H-11), 3.08 (1H, dd, J = 5.3, 2.5, H-3), 1 , 50 (1H, s, -OH), 1.30 (3H, d, J = 6.4, H-2 '); ir (CHCL) vmav: 3400 (N-H), 1760 cm -1 (c-o).

35

DK 161520 B

66 Z. Preparation of (1'S, 3R, 4R and 1'R, 3S, 4S) S-O-Methoxymethyl-1'-ethylQ-1- (paranitrobenzyl 2ll-hydroxy-2ll-acetate) -4-tritylthio -2-azetidinones (Isomer A) OCH2OCH3 OCH2OCH3 in Λ ~~ '

1U CO PNB

2

A mixture of isomer A of 3- (11-methoxymethyl-11-ethyl) -4-trityl-15-thio-2-azetidinone (7.5 g, 17.3 mmol), paranitrobenzyl, glyoxylate hydrate (4.7 g, 20 mL) , 8 mmol) and toluene (300 ml) were heated at reflux for 1 hour in a Dean Stark apparatus loaded with 3Å molecular sieves. The solution was cooled in ice and triethylamine (0.24 ml, 1.7 mmol) was added three times. The mixture was stirred for 1 hour, washed with dilute hydrochloric acid, sodium bicarbonate and brine, dried and concentrated to give the title compound as a foam (10.5 g, 94%). Hmr (CDCl 3) 6: 8.25-6.84 (19H, m, aromatic), 5.24 (2H, s, benzyls), 4.67-4.83 (3H, m, O-CH 4), 4.34-4.55 (1H, m, H-2 "), 4.02 (1H, m, H-1 '), 3.54 (1H, m, H-3"), 3, 40 (3H, s, O-CH 3), 1.38 (3H, j 25 d, J = 6.5, CH-); ir (KBr) νm: 3360 (OH), 1770 (C = 0 of β- lactam), 1735 (C = 0 of ester.) and 1605 cm (aromatic). J AA. Preparation of (1'S, 3S, 4R and 1'R, 3R, 4S) 3- (11-methoxymethoxy-1L) 1- (paranitrobenzyl 211-hydroxy-2,1-acetate) -4-tritylthio-2-azetidinone (isomer C)

AND AND

CHO I 2 3STr 35 A_-ySTr ^

0M · o ^ -vOB

CO PNB 2

DK 161520B

67

A solution of hydrated paranitrobenzyl glyoxylate (1.73 g, 7.11 mmol) was refluxed in toluene (90 ml) using a Dean Start apparatus loaded with 3Å molecular sieves for a period of 2 hours. To the boiling solution were added (1'S, 3S, 4R and 1'R, 3R, 4S) 05 3- (1'-methoxymethyloxy-1'-ethyl) -4-tritylthio-2-azetidinone (3.0 g, 6 93 mmol) and the mixture was refluxed for a further 2 hours.

The mixture was cooled to room temperature, triethylamine (70 mg, 97 μΙ, 0.69 mmol) was added and stirred for 2 hours. The reaction mixture was diluted with ether, washed with 1% aqueous HCl, water, 1% aqueous NaHCO 3, water and brine, dried (MgSO 4) and concentrated to give the title compound (4.60 g, 100%); ir (CHCl3) νmax: 3530 ° 3100 (0_H), 1765, 1750 (C = 0) and 1525 cm -1 (NO 2); 1 Hmr (CDCl 3) 6: 8.22, 8.18 (2H, 2d, J = 8, Hm aromatic), 7.67-7.0 (17H, m, H aromatic), 5.3 (2H, bs, CH2-PNB), 5.30-5.02 (m, H-2 "), 4.89-4.52 (m, HT and O-H), 4.63, 4.59 (1H , 2d, J = 2, H-4), 4.33, 4.30 (2H, 2 center of 2 abq, J = 7, J = 7, 0-CH 2 0), 4.1-3.67 (1H, m, H-1 '), 3.2 (1H, H-3), 3.1, 3.6 (3H, 2s, CHg-O), and 1.15 ppm (3H, d, J = 6.5, CH 3).

20 BB. Preparation of (TR, 3S, 4R and 1S, 3R, 4S) 3- (11-acetoxy-1'-11-ethyl) -1- (para nitrobenzyl-2 "-hydroxy-2" acetate) -4-tritylthio -2-azetidinone

25 OA C

X__S ** r Γ JC STr 'Γί -, Λγ ~ ί

J N TEA J - N OH

0 H

CO PNB

2 "Isomer B11

A solution of hydrated p-nitrobenzyl, glyoxylate (triturated with ether) (1.82 g, 30 moles) was refluxed in benzene through a Dean Stark 3-molecular-sieve apparatus, for 2 hours. To this was added azetidinone (1'R, 3S, 4R and 1'S, 3R, 4S) 3- (1'-acetoxy-1'-ethyl) -4-trityl-thio-2-azetidinone (10.88 g, 25 2 mmol) and the mixture was refluxed for an additional hour. The solution was cooled at room temperature and there

DK 161520 B

es was added triethylamine (0.35 ml, 2.5 mmol). The mixture was then stirred for 2 hours, followed by the reaction by TLC. Solvent evaporation gave a white foam in quantitative yield (100%, mixing of epimers). Alternatively, the solution can be washed with acid and base. ir (CH-CL) νm: 3520 (OH), 1775, 1745 cm "1 (C = O); 1Hmr '(CDCl3) δ: 8.2, 8.18 (2H, 2d, J = 8, aromatic), 7.80-6.90 (17H, m, H-aromatic), 5.28, 5.17 (2H, 24, C ^ -PNB, 4.89 (0.67H, d, J = 7.2, CHO), 4.80 (center of m, H-1 '), 4.38 (0.33 H, 2d, J = 8.8, CHO), 4.22 (D.33H, d , J4_3 = 2.5, H-4), 4.09 (0.67H, d, J4_3 = 2.1, 10H-4), 3.65 (D.67H, dd, J3_r = 5.8, J3 = 4, 2.1, H-3), 3.47 (0.33H,

dd, J3_n, = 5.5 J3 4 = 2.5, H-3), 3.33 (0.33H, d, J = 8.8, OH), 3.23 (0.67H, d, J = 7.5, OH), 1.88, 1.86 (3H, 2s, CH3CD), 1.10 1.06 (3H, I

2d, J = 5.8, 6.3, CH 3).

15 CC. Preparation of 3- (11-paranitrobenzyldioxycarbonyl-11-ethyl) -1- (paranitrobenzyl-2ll-hydroxy-2ll-acetate) -4-tritylthio-2-azetidinone (4 isomers) OCO PNB OCO2PNB · _. Yr J J H VH ^ Ν Ν-γ- ° Η CO PNB 2 25 "Isomer C11

A mixture of "isomer C" of 3- (1'-paranitrobenzyldioxycarbonyl-1'-ethyl) -4-tritylthio-2-azetidinone (1.70 g, 0.3 mmol), paranitrobenzyl, glyoxylate hydrate (815 mg, 3.6 mmol) and toluene (50 ml) were heated at reflux for 7 days in a Dean Stark apparatus loaded with 3Å molecular sieves. The cooled solution was washed with dilute hydrochloric acid, sodium bicarbonate and brine, dried and concentrated to give the title compound (2.1 g) as an epimeric mixture at carbon-2 ". Purification was done by chromatography over silica gel. The title compound could alternatively be prepared by using one catalytic amount of triethylamine.

DK 161520 B

69

Smaller polar epimer at 2 ": ³Hmr (CDCl) δ: 8.25-6.80 (23H, m, aromatic), 5.30 and 3.12 (4H, 2s, benzyls), 4.65 (1H , d, J = 9, H-2 '), 4.45 (1H, d, J = 2.5, H-4), 4.45-4.10 (1H, m, H-1'), 3.50 (1H, d, J = 9, 2 "-OH), 3.28 (1H, dd, J = 2.5, H-3) and 1.23 ppm (3H, 05 d, J = 6 , 5, CH 3); ir (CHCl 3) νmgx: 3530 to 3200 (D-H), 1765, 1750 (C = 0) and 1525 cm -1 (NOg). More polar isomer at C-211: 1 Hmr (CDCl 3) 6: 8.25-6.85 (23H, m, aromatic), 5.25 and 5.08 (4H, 2s, benzyls), 5.05 (1H, d, J = 7, H-2 "), 4.35 (1H, d, J = 2.5, H-4), 4.40-4.05 (1H, m, H-1 '), 3 , 42 (1H, J = 7, 2 "-OH), 3.33 (1H, dd, 10 J = 2.5, 2.5, H-3), 1.23 (3H, d, J = 6) , 5, CH 3); ir (CHCl 3) ν max: 3520 to 3200 (O-H), 1755 (C = O) and 1525 cm -1 (NOg).

"Isomer B"

A mixture of hydrated paranitrobenzyl glyoxylate (1.74 g, 7.66 mmol) and (1'R, 3S, 4R and 1'S, 3R, 4S) 3- (1'-paranitrobenzyl dioxycarbonyl-1'-ethyl) -4 -tritylthio-2-azetidinone (3.63 g, 6.38 mmol) was refluxed in toluene (70 ml) in a Dean Stark apparatus loaded with 3Å molecular sieves for 3 hours. The solution was cooled to room temperature and triethylamiri (64.5 mg, 89 ml, 0.639 mmol) was added. It was then stirred for 4 hours, diluted with ether and washed with 2% aqueous HCl, water, 2% aqueous NaHCO 3, water and brine. It was dried and concentrated to give the pure title compound (5.02 g, 100%). Separation of the 2 epimers was performed on preparative silica gel plate. Smaller polar epimer at 2 ": ir (CHCU) v____: 35oo * a <3 ΓΠαΧ 25 (O-H), 1772, 1750 (C = 0) 1525 cm" (NOg); Hmr (CDCl 3) δ: 8.30-8.0 and 7.65-6.80, (23H, m, aromatic), 5.27 and 5.13 (4H, 2s, benzyls), 4.71 (1H, m , J = 6.5, 6.5, H-1 '), 4.28 (1H, d, J = 2.2, H-4), 4.23 (1H, d, J = 8.7, H-2 "), 3.50 (1H, dd, J = 2.2, 6.5, H-3), 3.28 (1H, d, J = 8.7, OH) and 1.18 ppm (3H, d, J = 6.5, CH 3). More polar epimer: 30 µl (CHCL) νmav): 3480 (OH) 1772, 1750 (C = 0) and 1525 cm "1 (NO0);

Hmr (CDCl 3) δ: 8.35-6.90 (23H, m, aromatic), 5.15 (4H, benzyls), 4.72 (1H, d, J = 7.5, H-2 "O), 4 , 90-4.50 (1H, m, J = 6.5, 6.5, H-1 '), 4.10 (1H, d, J = 2, H-4), 3.68 (1H, dd, J = 2, 6.5, H-3), 3.28 (1H, d, J = 6.5, OH) and 1.15 ppm (3H, d, J = 6.5, CHg).

35

DK 161520 B

70 "Isomer A" "Isomer A" of S-O-paranitrobenzyldioxycarbonyM'-ethyl) + - trifthithio-2-azetidinone also gave a mixture of "Isomer A" of <(S-Cl'-paranitrobenzyldioxycarbonyM 1-Cparanitrobenzyl, 5 (2-hydroxy-2-acetate) -4-tritylthio-2-azetidinones. 1 Hmr (CDCl 3) δ: 8.3-6.7 (23H, m, aromatic), 5.17 (2H, benzyls), 5.0 (1H, m, H-11), 4.9 and 4, 8 (1H, 2d, J = 6, H-4, two epimers), 4.32 and 3.96 (1H, 2s, H-2 ", two epimers), 3.68 (1H, dd, J = 6 , 6, H-3 (and 1.47; ppm (3H, 2d, J = 6.5, CH 2, two epimers)) j 10; j "Isomer D"; "Isomer D" of 3- (1, -paranitrobenzyldioxycarbonyl-1, -ethyl) -4-it-tritylthio-2-azetidinone also gave a mixture of "Isomer D" of; 3- (1'-paranitrobenzyldioxycarbonyl-1'-ethyl) -1- (paranitrobenzyl 15 2 ") -hydroxy-2 "acetate) -4-tritylthio-2-azetidinones. 1 Hmr (CDCl 3) δ: 8.30-6.60 (23H, m, aromatic), 5.20 (4H, m, benzyls), 4.83 (1H, 2d, J = 5, H = 4), 5.50-4.30 (2H, m, H-1 'and H-2 "), 3.48 (1H, m, H- 3), 3.15 (1H, m, OH), 1.37 and 1.30 ppm (3H, 2d, CH 3).

i in 20 DD. Preparation of (1'S, 3S, 4R, and 11R, 3R, 4S) 3- (11-Methanesulfonyloxy-11-ethyl) -1- (paranitrobenzyl 211-hydroxy-2 "acetate) -4-tritylthio-2-acetidinone ( isomer C) (epimers at Cg ") in 25 PMs OMs Χ1γ8αφ3 30 co2pnb

A solution of paranitrobenzyl, glyoxylate hydrate (9.72 g; 42.6 mmol) in benzene (350 ml) was refluxed for 2 hours, azeotropically removing the water in a Dean-Stark trap. To this solution was added (1'S, 3S, 4R and 1, R, 3R, 4S) 3- (1'-methanesulfonyloxy-11-ethyl) -4-tritylthio-2-azetidinone (16.62 g, 35.5 mmol ), and

DK 161520 B

The 71 ling continued for another 0.5 hour. Then, the reaction mixture was cooled to room temperature, treated with triethylamine (0.5 mL; 3.5 mmol) and stirred for 3 hours to complete the reaction. Evaporation of the solvent gave a white foam, used as it were, in the next step. Hmr (CDCl 3) δ: 8.12 (2H, d, J = 9, Hm aromatic), 7.28 (17H, part of d H-aromatic, trityl), 5.28 (2H, s, -CH ) -PNB), 4.88 (0.5H, s, H-1 "), 4.62 (1.5H, m, H-2" and H-4), 4.00 (2H, m, H-1 ', - OH), 3.15 (1H, m, H-3), 2.73 (3H, s, mesylate and 1.30 ppm (3H, d, J = 6 Hz, H-2') ): ir v: 3520 (OH), 10 1775 (OO) and 1765 cm ”'(C = 0).

EE. Preparation of (TS, 3R, 4R and -1'R, 3S, 4S) SQ-Methoxyethyl-1'-ethylD-1- (paranitrobeny I-2ll-chloro-2 "acetate) -4-tritylthio-2- azetidinone 15 (Isomer A)

AND I AND I

- AVsc * 3 20 0 ^ γ0Η 'C02P “To2P» B.

Pyridine (1.1 ml, 14.2 mmol) was added dropwise to a solution of

Isomer A of S-O-methoxymethyl-1'-ethylO-1-Cparanitrobenzyl ("hydroxy-2" acetate) -4-tritylthio-2-azetidinone (7 g, 10.9 mmol) in THF (350 ml) cooled to -15 ° C. Immediately thereafter, thionyl chloride (1.0 ml, 14.0 mmol) was added dropwise and the mixture was stirred at -15 ° C for 0.5 hour. The precipitate was removed by filtration and washed with benzene. The combined filtrates were concentrated, the residue was dissolved in fresh benzene, and the solution was treated with activated charcoal, filtered and concentrated to give the title compound as an oil (6.5 g, 90%), 3 Hmr (CDCl 3) δ: 6.65 8.35 (19H, m, aromatic), 5.24 (2H, s, benzyl), 3.43 (3H, s, OCH 3) and 1.42 ppm (3H, d, J = 6, CH .

DK 161520 B

72 FF. Preparation of (1'S, 3S, 4R and 1'R, 3R, 4S) S-n'-Ethoxymethyloxy-1'-ethyl) -1- (paranitrobenzyl 2ll-chloro-2ll-acetate) -4-trylthiothio 2-azetidinone in (Isomer C) j 05 OCH2OCH3? CH2OCH3 J. STr J .STr

/'·-.(—/ soci2 —S

TO CO PNB CO PNB

2 I

A cold (ice-MeOH bath) THF- (60 mL, distilled over LAH) dissolves solution of (1'S, 3S, 4R and 1'R, 3R, 4S) 3- (1'-methoxymethyloxy-1 -ethyl) -1-paranitrobenzyl 2 "-hydroxy-2" acetate) -4-tritylthio-2-azetidinone (4.25 g, 6.62 mmol) was treated dropwise with pyridine (0.696 mL, 8.61 mmol) ) and thionyl chloride (0.530 ml, 8.61 mmol). The mixture was stirred for 30 minutes at -15 ° C. The precipitate was collected by filtration and washed with benzene. The THF-benzene solution was concentrated and the residue dissolved again in benzene. Charcoal removal on a Celite pad and subsequent evaporation of benzene gave the title compound (4.86 g, 100%); ir (CHCl 3) vma): 1770 (C = 0) and 1525 cm (NOG); Δ: 8.15, 8.12 (2H, 2d, H-aromatic), 7.70-7.00 (17H, m, H-aromatic), 5.62, 5.02 ( 1H, 2s, H-2 "), 5.27 (2H, s, CHg-PNB), 4.7 (1H, d, H-4), 4.7-3.7 (m, O-CH 0, H-11), 3.5-2.8 (m, H-3), 3.12, 3.08 (3H, 2s, O-CH 3) and 1.30-0.96 ppm (3H, m, CH 2).

30 GG. Preparation of (1 * R, 3S, 4R and 1'S, 3R, 4S) 3- (11-Acetoxy-11-ethyl) -1- (para-nitrobenzyl 2ll-chloro-2ll-acetate) -4-tritylthio 2-azetidinone? Δ ° βτ fC STr „/ 'w® sol, oØ oH Jj <*

C02PNB C02raB

DK 161520 B

73 ”Isomer B11

A THF (distilled over LAH) solution of (1'R, 3S, 4R and 1'S, 3R, 4S) 3- (1'-acetoxy-1'-ethyl) -1- (paranitrobenzyl-2 "-hydroxy-5 -2 "acetate) -4-tritylthio-2-azetidinone (from 10.88 g NH) was treated at -15 ° C (ice-methanol bath) under a nitrogen atmosphere with pyridine (2.19 g, 2 24 ml, 27.7 mmol) and thionyl chloride (3.3 g, 2.02 ml, 27.7 mmol) and thionyl chloride (3.3 g, 2.02 ml, 27.7 mmol).

The mixture was stirred for 20 minutes at -15 ° C. The salt was filtered off and washed with benzene. Solvent evaporation (THF + benzene) gave a residue which was taken up in benzene (hot) and treated with charcoal. The suspension was filtered through a Celite pad and solvent evaporation gave a white foam; ir (CH 2 Cl 2) v: 1780, 1740 cm -1 (C = O) 1 Hmr (CDCL) 6: 8.17, 8.21 (2H, 2d,

ΓΠ3Χ O

J = 8, Ho-aromatic) 7.76-6.88 (17H, m, H-aromatic), 5.31, 5.16, 5.12, 4.73 (3H, 4s, C , CHCl) 5.12-4.55 (1H, m, H-1 '), 4.35-4.25 (1H, m, H-4), 3.80-3.45 (1H, m , H-3) 1.90 (3H, s, CH 3 CO), 1.12, 1.07 (3 H, J = 6.5, CH 3).

20 HH. 3- (1 '-paranitrobenzyldioxycarbonyM'-ethyl) -1- (paranitrobenzyl 2ll-chloro-2ll-acetate) -4-tritylthio-2-azetidinone (mixture of epimers at C2 ").

25 OCO PNB OCO PNB

AJ> * 3 __ ^ * γ “" "γ«

CO PNB CO PNB

2. Isomer C

Pyridine (58 mg, 0.73 mmol) was added dropwise to a solution of "isomer C" of 3- (1'-paranitrobenzyldioxycarbonyl-11-ethyl) -1- (paranitrobenzyl 2 "hydroxy-2" acetate ) -3-tritylthio-2-azetidinones (470 mg, 0.6 mmol); mixture of epimers at C-2 ") in THF (15 ml) cooled to -15 ° C. Immediately thereafter thionyl chloride (86.5 mg,

DK 161520 B

74 0.73 mmol) dropwise and the mixture was stirred at -15 ° C for 0.5 hour.

The precipitate was removed by filtration and washed with benzene. The combined filtrates were concentrated, the residue dissolved in fresh benzene, and the solution treated with activated charcoal, filtered, and concentrated to give the title compound as an oil. 530 mg; 100%. 1 Hmr (CDCl 3) 6: 8.7-6.8 (23H, m, aromatic), 5.53 (1H, s, H-2 "), 5/30 and 5.17 (4H, 2s, benzyls) , 4.52 (1H, d, J = 2, H-4), 4.20-3.70 (1H / m, H-1 '), 3.31 (1H, dd, H-3), 1 , 27 and 1.21 ppm (3H, 2d, J = 6.5); ir (CHCl) v * 1780, 1750 (C = 0) and 1525 cm -1

"Isomer B11" Isomer B "of 3- (1-paranitrobenzyldioxycarbonyl-1'-ethyl) -1- (paranitrobenzyl 2,1-chloro-2" acetate) -4-tritylthio-2-azetidinones | 15 (mixture of C-2 "epimers) was prepared as described above for" isomer C "in quantitative yield. 1 Hmr (CDCL ·) δ: 8.25-6.90 (23H, in µm, aromatic), 5 , 40-5.0 (4H, m, benzyls), 5.40-4.45 (1H, m, j H-1 '), 4.82 and 4.57 (1H, 2s, H-2 ") , 4.36 and 4.31 (1H, 2d, J = 2.5, j H-4), 3.63 (1H, m, J = 2.5, J = 6.5, H-3), 1.25 and 1.18 ppm (3H, 2d, | 20 J = 6.5, CH 3; ir (CHCl 3) max: 1780, 1750 (C = O) and 1525 cm -1 (NOp. | Isomer A) "Isomer A" of S-O-paranitrobenzyldioxycarbonyM'-ethylO-1'- (paranitrobenzyl 2 "-chloro-2" acetate) -4-tritylthio-2-azetidinones (mixture of C-2 "- 1 Hmr (CDCl 3) δ: 8.30-6.80 (23H, m, aromatic), 5.45-4.80 (1H, m, H-1 ') / 5.18 and 5.21 (4H, 2s, benzyls), 4.87 (1H, 2d, H-4), 4.22 and 3.87 (1H, 2s, H-2 "), 4.05-3.40 (1H, m , H-3), 1.57 and 1.50 ppm (3H, 2d, CH 3).

"Isomer D" "Isomer D" of S-1-paranitrobenzyldioxyGarbonyl-1'-ethyl-1 '- (paranitrobenzyl 2 "-chloro-2" acetate) -4-tritylthio-2-azetidinones (mixture of C 2 "epimers). 1 Hmr (CDCl 3) δ: 8.30-6.70 (23H, m, aromatic), 5.32-5.10 (4H, m, benzyls), 5.48 and 5.30 ( 1H, 2s, 35H-2 "), 4.82 (1H, d, J = 5, H-4), 5.30-5.20 (1H, m, H-1 ') / 3.15 ( 1H, m, H-3), 1.40 and 1.30 ppm (3H, 2d, J = 6.5, CH 2); ir (CHCL) νm: 1780, 1750 (C = O) and 1525 cm "1 (NO₂).

75 DK 161520 B

11. Preparation of (1'S, 3S, 4R and 11R, 3R / 4S) -3- (11-methanesulfonyloxy-11-ethyl) -1- (paranitrobenzyl 2 "-chloro-2ll-acetate (-4-tritylthio-2) -ezetidinone (isomer C) (epimers at C2 ").

05 OMS fMS -pJ.

"τΥ50 * 3 3, _N OH J — N Cl

ίο 0 Y ^ T

CO PNB co2pnb

To a cold solution (5 ° C of (1'S, 3S, 4R and 1'R, 3R, 4S) 3- (1'-15-methanesulfonyloxy-1'-ethyl) -1- (paranitrobenzyl 2 "-hydroxy-2 4-Tritylthio-2-azetidinone (24.0 g, 35.5 mmol) in dry tetrahydrofuran (350 ml) was added pyridine (3.65 g, 46.2 mmol) and thionyl chloride (5.5 g, 46.2 mmol dropwise After stirring for 45 minutes, ether (100 ml) was added to precipitate the hydrocloride salt which was filtered off.

The filtrate was evaporated and the residue was redissolved in benzene (200 ml) and treated with charcoal. Evaporation of the solvent gave an almost white foam which was used, as it were, in the next step.

Hmr (CDCl 3) δ: 8.18 (2H, d, J = 9, Hm aromatic), 7.72 (17H, m, part of d H aromatic, trityl), 5.57 and 5.12 (1H, s, H-2 "), 5.28 (2H, s, -CH2PNB), 4.73 (1H, 2d, H-4), 3.21 (1H, 2dq, H-3), 2.78 (3H, 2s, mesylate and 1.21 ppm (3H, 2d, H-6Ho? H-21)) * v: 1779 η (L max cm -1 (C = 0)).

JJ. Preparation of 30 (1'S, 3R, 4R and TR, 3S, 4S) S-Q'-methoxymethoxy-V-ethyl) -1- (paranitrobenzyl 2ll-triphenylphosphoranylidene-2ll acetate) - 4-tritylthiQ-2 -acetidinone (isomer A) and 2 and 3 OCH 2 OCH 3 35 JL / γ S1 * 30 OJ-'L.CI * <Τ ~ ι, 'γ ^ ρφ3 CO ^ NB co2pnb

DK 161520 B

76

A mixture of isomer A of 3- (11-methoxymethoxy-1'-ethyl) -1- [(paranitrobenzyl) -2 "-chloro-2'I-acetate) -4-tritylthio-2-azetidinone (6.6 g , TO mmol), triphenylphosphine (3.3 g, 12.5 mmol), 2,6-lutidine (1.3

ml, 11 mmol) and dioxane (140 ml) were heated at reflux for 205 days. The solution was diluted with ether, washed with dilute acid (5% HCl), water, diluted sodium bicarbonate and brine, dried and concentrated. The residue was purified by chromatography on silica gel eluting with 10% ether in benzene. Con- I

centering the relevant fractions gave the title compound as a foam (1.4 g, 13.7%) ir (KBr) v: 1750 (C = 0) and 1660-1650 cm

ΓΠαΧ I

(C = C, aromatic). 1 KK. Preparation of (T'S, 3S, 4R and 1'R, 3R, 4S) 3- (11-methoxymethyloxy-11-ethyl) -15-1- (paranitrobenzyl 211-triphenylphosphoranylidene-211-acetate) -4-tritylthio 2-azetidinone (isomer C).

in

OCHOCH- · OCHOCH

2 3 I 2 3 20 ** 3 A / STr 0Α »ί.α <J ~ Α *? Φ3

C02PNB CO ^ PNB

25

A dioxane (100 ml, distilled over LAH) solution of (1'S, 3S, 4R and 1'R, 3R, 4S) S-O-methoxymethyloxy-1'-ethylO-1-ipara-nitrobenzyl-2 "chlorine -2ll-acetate) -4-tritylthio-2-azetidinone (4.86 g, 6.62 mmol), triphenylphosphine (2.60 g, 9.93 mmol) and 2,6-lutidine (770 mg, 0.837 ml (7.20 mmol) was heated under reflux for 4 hours and kept in a hot bath (100 ° C) for 16 hours. The mixture was diluted with ether, washed with 1% aqueous HCl, water, 10% aqueous NaHCO 3, water and brine. The solution was concentrated and the residue filtered through a silica gel (65 g) column (5%, 10% 35 and 20% ether-benzene) to give the title compound (2.8 g, 48%). (CHCL) v: 1795 (C = O), 1620 and 1605 (phosphorane), and 1515 cm (1) (NO 2).

05

DK 161520 B

77 LL. (1'R, 3S, 4R and 1'S, 3R, 4S) S-Q'-acetoxy-V-ethylO-Xparanitro-benzyl-2ll-triphenylphosphoranylidene "2" acetate) -4-tritylthio-2- · azetidinone (isomer B) PAc OAc X / STr V ^ · ί — Τ5Τγ Ύ '0 ^ -Ν \ ^ Φ3

-jq co2pnb C02PNB

A dioxane (100 ml, fresh kdest I clay over LAH) solution of crude (1'R, 3S, 4R and 1'S, 3R, 4S) 3- (1'-acetoxy-1'-ethyl) -1- (paranitrobenzyl) (2 "-chloro-2-acetate) -4-trimethylthio-2-azetidinone was treated with 2,6-lutidine (2.97 g, 3.23 ml, 27.72 mmol) and triphenylphosphine (9.91g The mixture was refluxed (oil bath 130 ° C) for 18 hours. The solvent was evaporated and the residue redissolved in methylene chloride. The resulting solution was washed successively with dilute 20 HCl, H 2 O, dilute aqueous NaHCO 3 Drying and solvent evaporation gave the title compound as a solid which was triturated with ether and collected by filtration (14.6 g, 65.9%); ir (CI-LCL) mp: 1750 (C = 0) and 1620 , 1610 cm

b l ITIdX

phoran).

25 MM. 3-1l-paranitrobenzyld? Oxycarbonyl-1l-ethyl) -1- (paranitrobenzyl) - 211-triphenylphosphoranylidene-acetate 2LL) -4-tritylthio-2-azetidinone.

OCO PNB OC02PNF

30 X_ ^ 3 _, Λ-γ3 ^ 3 o ^ yci

CO PNB C02PNB

35

DK 161520B

78

ISOMER B

A mixture of (1'R, 3S, 4R and 11S, 3R, 4S) 3- (1'-paranitrobenzyl-dioxycarbonyl-11-ethyl) -1- (paranitrobenzyl-2L, -chloro-2 "acetate) 4-triethylthioazetidinone (isomer B) (4.96 g, 6.22 mmol), mixture of epimers, 05 at C-2 "), triphenylphosphine (2.47 g, 9.42 mmol) and 2, 6-lutidine (740 mg, 0.80 ml, 6.91 mmol) was refluxed in dioxane (freshly distilled over LAH) for 30 hours. The solution was diluted with ether and ethyl acetate, washed with 5% aqueous HCl, water, 10% aqueous NaHCO 3, water and brine, and dried (MgSO 4). Evaporation of solvent gave a residue which was passed through a silica gel (10 ..... times its weight) column (10% ether-benzene, ether and ethyl acetate). j

The title compound was obtained as a crystalline solid (3.1 g, 49%), m.p. 189-190 ° C (ether); ir (CHCU) νm: 1750 (C = O), 1620, 1605;

(phosphorane) and 1522 cm (NO 2). IN

Isomer C of _____ Isomer C of S-O-paranitrobenzyldioxycarbonyM'-ethyO-1- (- (paranitrobenzyl-2, - triphenylphosphoranylidene-2 "acetate) -4-tritylthio-2-azetidinone was prepared as described above for isomer B.

20 µl (CHCL) v: 1750 (C = O), 1610, 1620 (phosphorane) and 1520 cm cm ^ «max (NO₂); Hmr (CDCl 3) δ: 8.6 = 6.7 (H-aromatic), 5.22 and 4.95 (benzyls), 4.70 (H-4), 2.6 (H-3), 1, 19 and 1.07 ppm (CHg).

in ISOMER D; A mixture of isomer D of 3- (1'-p-nitrobenzyldioxycarbonyl-1-ethyl) -1- (p-nitrobenzyl 211-chloro-2,1-acetate) -4-tritylthio-2-azetidinone (4,598 g , 4.45 mmol; purity 77%, mixture of epimers at C-2 "), triphenylphosphine (1.425 g, 5.44 mmol; Aldrich) and 2,6-lutidine (0.63 ml, 580 mg, 5.40 mmol; Anachemia) in dioxane (65 mL; distilled from LAH) was heated under gentle reflux for 3 hours for 41 hours, monitoring the reaction by TLC (benzene: ether = 3: 1).

The dark reaction mixture was cooled, diluted with EtOAc and washed successively with 0.1 NHCl, water, 2% NaHCO 3 and then brine. Drying (Na 2 SO 4) and evaporation of the solvents 35 gave 4.18 g of a dark colored oil which was purified by column chromatography (SiO 2, 88 g; eluent 10-25% ether in benzene) and a yield of 1.108 g (1 , 08 mmol, yield 24.3%) of the title compound

DK 161520B

79 the binding ice as a yellow foam: Hmr (CDCl 3) δ: 1.08 (d, J = 6Hz, 1'-CH 2); ir (pure) v: 1745 cm 1 ((s, C = 0).

«3 ΓΠ3Χ NN. Preparation of 05 (1'S, 3S, 4R, and 1'R, 3R / 4S) S-Q'-Methanesulfonyloxy-1'-ethyl) -1- (paranitrobenzyl 2ll-tri-phenylphosphoranylidene-2ll-acetate) - 4-tritylthio -2-azetidinone (isomer C)

10 CMS OMS

</ - «, y« * J-Ny * 3 CO PNB co2pnb 15

A solution of (1, S / 3S / 4R and 1, R / 3R, 4S) 3- (1'-methanesulfonyl-oxy-V-ethyl) -1 - (paranitrobenzyl-2L, -chloro-2 "acetate) -4-tritylthio-2-azetidinone (24.7 g, 35.5 mmol), triphenylphosphine (11.2 g, 42.7 mmol) and 2,6-lutidine (4.2 g, 39.1 mmol) in dry dioxane (350 ml) was refluxed under nitrogen for 19 hours. The solvent was evaporated and the crude product was redissolved in ethyl acetate and washed successively with dilute HCl, NaHCO 3 and brine. Purification was completed by chromatography on a silica gel column (8.5 x 12 cm). Elution with 10% ether-dichloromethane (1.5 liters) and then ether (1.5 liters) gave the purified phosphorane; 12.36 g (40%). 1 Hmr (CDCl 3) θ: 2.53 and 2 , 93 ppm (3H, 2s, mesylate); ir vm: 1749 ° 9 1620 cm -1 (C = 0). Max ° 0 0. Preparation of 30 (1'R, 3S, 4R and 11S, 3R, 4S) - 3- (11-hydroxy-11-ethyl) -1- (paranitrobenzyl-2 "-triphenylphosphoranylidene-211-acetate) 4-tritylthio-2-azetidinone (isomer B) OAc oh A. Tr 35 “Γη _552! L-► f ο ^ -Ν-γ · ΡΦ3

CO PNB CO PNB

in"

DK 161520 B

80

A solution of phosphorane (1, R / 3S / 4R and 1'S, 3R, 4S) -3- (1'-J

-acetoxy-1, -ethyl) -1- (paranitrobenzyl-2 "-triphenylphosphoranylidene-I

-2 "acetate) -4-tritylthio-2-azetidinone (4.43 g, 5.00 mmol) in methanol (10 ml) THF (60 ml) was treated at room temperature with 1% aqueous 05 NaOH (1 eq. The reaction was followed by ether-ethyl acetate and washed with HCl, H 2 O, aqueous NaHCO 3, hgO and brine. Evaporation of solvent gave a residue which crystallized from

benzene ether (3.7 g, 87.7%), m.p. 169,5-170,52C. ir (CP ^ C ^) I

10 v: 1745 (C = 0) and 1620 cm 2 (phosphorane). ! max

Heating the mixture increased the reaction rate. j PP. Preparation of 15 (1'S, 3R, 4R and 1'R, 3S, 4S) -silver 3- (11l-methoxymethyl-11l-ethyl) -1-paranitrobenzyl-2ll-triphenylphosphoranylidene-2ll-acetate) - 2- azetidinone-4-thiolate (isomer A) j OCH2OCH3 001200¾ V __. V "" Λν »," '> · *.

/ 3 C02PNB

Silver 3- (1, -methoxymethyl-11-ethyl) -1- (paranitrobenzyl-2 "tri-phenylphosphoranylidene-2" acetate) -3-tritylthio-2-azetidinone (isomer A) was prepared as described. elsewhere for isomer C of the paranitro-benzyldioxycarbonyl derivative. Yield 50%. ir (pure) v:): 1745 cm (C = 0).

QQ. Preparation of VS, 3S, 4R and 11R, 3R, 4S) -Silver-2- (11-methoxymethyloxy-11-ethyl) -1- (paranitrobenzyl-211-triphenylphosphoranylidene-211-acetate) -azetidinone-4-thiolate ( isomer C)

DK 161520B

81 AND-OCH., OCH2OCH-j

J 'STr I

^ '- 1 — C AgN03 —s' 05 cr N \ j ^ P ^ 3

CO PNB co PNB

z 2 10 (1'S, 3S, 4R and 1, R, 3R / 4S) -3- (1, -methoxymethyloxy-1'-ethyl) -1- - (paranitrobenzyl-2 "-triphenylphosphoranylidene-2n-acetate) -4-Trityl-thio-2-azetidinone (887 mg, 1.0 mmol) was first dissolved in hot (40 ° C) methanol (30 ml), treated with pyridine (103 mg, 0.105 ml, 1.3 mmol) and After cooling with a 0.15 m methanol solution 15 of silver nitrate (8.7 ml, 1.3 mmol), the mixture was stirred for 1 hour at 23 ° C, cooled (ice bath) and stirred for 20 minutes. The salt was filtered and washed successively. with cold methanol and ether (3 times, 671 mg / 87%). ir (CHCL) ν, 1745 (C = O), 1605 (phosphorane) and 1520 cm (NC).

20 RR. Preparation of Silver 3- (1 '-paranitrobenzyldioxycarbonyM'-ethyl) -1 - (paranitro-benzyl-2L> -triphenylphosphoranylidene-2ll-acetate) -2-azetidinone-4-thiolate 25

° “2ΡΝΒ OCO-PNB

_ι) γγ “9

30 ίο ΡΗΒ CO PNB

z 2 "Isomer B11 35 (1'R, 3S, 4R and 1'S, 3R, 4S) -3- (1'-paranitrobenzylcarbonyldioxy-1, -ethyl) -1- (paranitrobenzyl-2" -triphenylphosphoranylide-2 "- acetate) - 4-Trithio-2-azetidinone (1.02 g, 1 mmol) was first dissolved in CF

DK 161520 B

ml) and diluted with hot (55 ° C) MeOH (20 ml). The hot solution was first treated with pyridine (120 ml, 117 mg, 1.48 mmol) and a hot (55 ° C) 0.15 m methanolic silver nitrate solution (8 ml, 1.2 mmol). The mixture was stirred at room temperature for 15 minutes, then at 0 ° C for 2 hours. It was then concentrated to a 10% solution in a rotary evaporator (no bath). The mercaptide was filtered and washed twice with cold (-15 ° C) methanol and three times with ether. (917 mg, 100%). ir (nujol mull) v: 1745 (C = 0), 1600 (phos- ΓΠαΧ phoran) and 1517 cm (NC NC).

"Isomer C" Silver S-O-paranitrobenzyldioxycarbonyM'-ethylO-1-iparanitro-benzyl-2 "-triphenylphosphoranylidene-2" -triphenylphosphoranylidene-2-acetate) -2-azetidinone-4-thiolate, " Isomer C "was prepared as described above for" Isomer B "; ir (nujol) v: 1745 (C = 0) and ΓΠαΧ in 1600 cm (phosphorane)." Isomer D "

A solution of Isomer D of β - (1'-p-nitrobenzylcarbonyldioxy-1,120-ethyl) -1- (p-nitrobenzyl-2 "-triphenylphosphoranylidene-2" acetate) -4- -tritylthio-2-azetidinone (145 mg, 0.142 mmol) was prepared by first dissolving it in (5 ml), removing CH 2 Cl 2 at 55 ° -60 ° C. and hot MeOH (4 ml) was added. To the above solution was added a warm solution of AgNOg in MeOH (0.15 m, 1.14 ml, 0.17 mmol, 1.2 equiv), followed by pyridine (14 μΙ, 0.17 mmol, 1.2 eq.), the silver mercaptide immediately began to precipitate. The mixture was stirred for 2 hours at room temperature and for 1 hour at 0 ° C. The mercaptide was collected by filtration and washed with ice-cold MeOH and ether to yield 99 mg (0.11 mmol, 78%) of the title compound as a brownish solid: ir (nujol) v: 1750 cm C = 0).

ΧαΧ 35

83 DK 161520 B

SS. Preparation of (VR, 3S, 4R and 11S / 3R / 4S) -silver-3- (11-hydroxy-11-ethyl) -T -) - paranitrobenzyl-211-triphenylphosphoranylidene-2 "acetate) -2-azetidinone 4-thiolate (isomer B) 05 oh oh J, ^ ST r IS Ag ·

-r AgN03 XV-S

0J — n ΡΦ3 c5h5n] _ΐ! ^ Ρφ3 ίο T ° r co2pnb co2pnb

A solution * of (1'R, 3S, 4R and 11S / 3R, 4S) -3- (1'-hydroxy-11-15-ethyl) -1- (paranitrobenzyl-2 "-triphenylphosphoranylidene-2" acetate ) - -4-Tritylthio-2-azetidinone (1g, 1.19mmol) in MeOH (10ml), treated with pyridine (124µl, 121.3mg, 1.53mmol) and at 10 ° C with a 0.15 m solution of silver nitrate in MeOH (15 ml, 2.25 mmol) - or until the precipitation of silver mercaptide ceased) The mixture was stirred for 20 hours and concentrated in the rotary evaporator (no bath) to a concentration of about 10%. The solvent was filtered off. The cake was washed once with MeOH and 3 times with ether and pumped under high vacuum (954 mg, 100%). Ir (nujol mull) vm: 3500-3400 (OH), 1752 (C = 0) 1595 (phosphorane) and 1525 cm -1 (NOp).

25%

The crystalline material was first dissolved in CH 2 Cl 2.

Example 6 (1'R, 5R, 6S and 11S, 5S, 6R) -6- (11-hydroxyethyl) -2- (2-aminoethoxymethyl) -penem-3-carboxylic acid (isomer B)

OH

0JlO ^ H20CH2CH2NH2 co2h 84

DK 16152 OB

(1 * R, 3S, 4R and 1'S, 3R, 4S) 4- (2-Azidoethoxy) -acetylthio-3- (11-hydroxyethyl) -1- (p-nitrobenzyl-2ll-triphenylphosphoranylidene-Z -Z-azetidinone (isomer B) 05 h

V "w fr> X

A ·· * · ~ s

2 · co2pnb CC ^ PNB

To a stirred solution of (1'R, 3S, 4R and 1'S, 3R, 4S) -silver-3- (1'-hydroxyethyl) -1- (p-nitrobenzyl) -2 "-triphenylphosphoranylidene-2 Acetate) -2-azetidinone-4-thiolate (isomer B) (820 mg, 1.16 mmol) in THF (20 ml) was added at -15 ° C (MeOH ice bath) under Ng atmosphere successively triethylamine ( 01648 ml, 4.66 mmol; 4.02 eq), chlorotrimethylsilane 20 (0.589 ml, 4.64 mmol, 4.00 eq) and imidazole (81.2 mg, 1.12 mmol).

The mixture was stirred at room temperature for 18 hours (overnight) and then cooled to -10 - -15 ° C. Pyridine (0.220 mL, 2.72 mmol) and then a solution of 2-azidoethoxyacetyl chloride (372 mg, 2.27 mmol, 1.96 eq) in Ch 2 Cl 2 (20 mL) was added. It was stirred at room temperature for 1 hour. After filtration of the precipitate, the filtrate, diluted with EtOAc, was washed successively with 1 n HCl, brine, saturated NaHCO 3 and brine, dried (10 SO 2) and evaporated in a yield of 784 mg as an oil. This oil dissolved in wet (20 ml with 3 drops of water) was treated with trifluoroacetic acid (2 drops) at room temperature for 30 minutes. The mixture was washed with saturated NaHCO 3 and then brine, dried (t 2 SO 2) and evaporated to yield 695 mg of a crude oil.

This oil was purified by column chromatography (SiC ^, 15 g, eluant EtOAc: 01 ^012 = 1: 1), collecting 538 mg (0.739 mmol, yield 63.7%) of the title compound as a yellow oil: 1 Hmr (CDClCl ) δ: 1.22 (d, J = 6Hz, CHg-T), 5.6 (2D, H-4) and 7.3 = 8.4 ppm (aromatic Hs); ir (pure) v: 3420 (OH), 2100 (-NQ), 1750 (C = O), and 1690 cm -1 nricix o (thioester); Rf 0.20 (CH 2 Cl 2: EtOAc = 1: 1).

85

DK 16152GB

(1'R, 5R, 6S and 1'S, 5S, 6R) p-nitrobenzyl 6- (1'-hydroxyethyl) + - (2-azidoethoxymethyl) penem-3-carboxylate (isomer B)

OH

° H s s

05} 'u' \ - f toluene * 1 1 —CH AND CH N

JJ ^ 3 - ^

o 3 CO PNB

CO PNB 2 2 10 A solution of (1'R, 3S, 4R and 1'S, 3R, 4S) -4- (2-azidoethoxy) -acetylthio-3- (1I-hydroxyethyl) -1- (p-nitrobenzyl) 2 "-Triphenylphosphoranylidene-2" acetate) -2-azetidinone, (isomer B) (490 mg, 0.673 mmol) in toluene (80 ml) was heated at reflux for 3 hours.

Evaporation of the solvent in vacuo gave an oily residue which was purified by column chromatography (SiO 2, 10 g; eluent 5-10% EtOAc in CH 2 Cl 2) followed by crystallization from CH 2 Cl 2 ether to yield 202 mg (0.449 mmol). 66.8% of the title compound as pale yellow crystals: 1 Hmr (CDCl 3) δ: 1.35 (3H, d, J = 6.5 Hz, CH 3-1 ') / 2.18 (1H, br, OH) , 3.2-3.9 (5H, m, 20 -CH2 and H-6), 3.9-4.5 (1H, m, H-11), 4.45-4.72-4.75 -5.02 (2H, AB type, CH2 ~ 2), 5.02-5.25-5.35-5.57 (2H, AB type, -CHgAr), 5.62 (1H, d, (J = 1Hz, H-5) and 7.42-7.65-8.13-8.28 ppm (4H, A ^ B ^, aromatic Hs); ir (nujol) v: 3460 (-OH), 2110 (-N₂), 1765 * max ό (β-lactam) and 1680 cm ((ester) An analytical sample was obtained by further crystallization: mp 107-108 ° C (CH 2 Cl 2 ether uv (EtOH)

Xmax: 264 (ε 12000) and 323 m | J (ε 9200); Rf 962 (CH 2 Cl 2: EtOAc = 1: 1); Analysis calculated for C18 H19 N5 ° 7S: C, 48.10; H, 4.26; N, 15.88; S, 7.13;

Found: C, 47.81; H, 4.18; N, 15.00; S, 7.16

DK 161520 B

86; (VR ^R RS abd VS, 5S, 6R) ε-1'-hydroxyethylQ ^^ - azidoethoxy-methyl-penem-3-carboxylic acid (isomer B)

OH OH

-: - "ojZXy CO PNB Λζο H j ^ 2 j. 10

A solution of (1'R, 5R, 6S and 1'S, 5S, 6R) p-nitrobenzyl-6- (1'-hydroxyethyl) -2- (2-azidoethoxymethyl) -penem-3-carboxylate (isomer B) ( 180 mg, 0.400 mmol) in THF (18 ml) was mixed with ether (19 15 ml), H 2 O (18 ml) and 10% Pd-C (180 mg). It was hydrogenated (H 2, 55 psi) at room temperature for 2.5 hours. After filtering off the catalyst, the aqueous filtrate was washed with EtOAc and lyophilized; yield 84.4 mg (0.293 mmol, crude yield 73.2%) of the title compound as a pure yellow powder: uv (Η ^ Ο) λ: 305.5 (ε 4800) and 255 mp 20 (ε 3800). This powder was purified by HPLC (Waters C ^ g Micro Bondapack Reverse Phase, 30 cm x 10 mm); eluant 1% CH 2 CN in H 2 O) to give 44.7 mg (0.155 mmol), yield 38.8%) of the title compound as a white powder: 1 Hmr (D 2 O) δ: 1.34 (3H, d, J = 6, 4 Hz, CH3-1 '), 3.26 (2H, m, -CH2N), 3.82 (2H, m, 25 -2ΟΗ2-), 3.94 (1H, dd, J6_r = 6.2Hz, Jg_5 = 1.4 Hz, H-6), 4.2-4.4 (1H, m, H-1 '), 4.52-4.70-4.84-5.02 (2H, AB type, CH2-2) and 5.71 ppm (1H, d, J = 1.3 Hz, H-5); ir (KBr plate) v: 3420 (OH), 3000-2600 (br, CO 2 H), 1765 (β-lactam), and 1575 crn 2 H (-CO 2 H), uv (H 2 O) ^ max: 306 (ε 5300) and 258 mp (ε 3600).

30 35

DK 161520B

87

Example 7 2- (2-Aminoethoxymethyl) penem-3-carboxylic acid (via mercaptide intermediate) 05 sec I CH 2 CH 2 CH 2 CO 2 CH 2

Ethyl 2-chloroethoxyacetate 15 VTEAB EtQ / Cl iso »20 A mixture of ethyl chloroacetate (24.5 g, 0.200 mol), ethylene oxide (8.80 g, 0.300 mol) and tetraethylammonium bromide (0.40 g, 1 (9 mmol; dried under vacuum) was heated in a bomb at 150-160 ° C for 6 hours. After cooling, the reaction mixture was distilled under reduced pressure to collect 6.66 g (54.4 mmol, 27.2%) of ethyl chloroacetate, b.p. 22-24 ° C (0.5 mm Hg) and 8.39 g (50.4 mmol), 25.2%) of ethyl 2-chloroethoxyacetate as a colorless oil; kp. 49-53 ° C (0.1 mm Hg); 1 Hmr (CDCl 3) δ: 1.28 (3H, t, J = 7 Hz, -CH 2), 3.5-4.0 (4H, m, A 2 B 2, -CH 2 CH 2 -Cl), 4.15 (2H, s, -COCH 2 O-), 4.25 ppm (2H, q, J = 7Hz, -0CH 5 CH 2); ir (pure) v: 1740 cm -1 (C = 0 ester).

Method according to D. Klamann et al., Jastus Liebig Ann., 710, 59 (1967) (reported: yield 42%, bp 55.5 ° / 0.35 mm Hg).

Ethyl -2-azidoethoxyacetate Eto ... J-'L NaN Eto. ..

88 DK 161520 B

A mixture of ethyl 2-chloroethoxyacetate (7.71 g, 36.3 mmol) and sodium azide (3.31 g, 50.9 mmol) in DMF (100 ml) was heated at 80-90 ° C for 3.5 hours. , after which TLC (hexane ether 1: 1) showed that the reaction was complete. The cooled mixture was poured into H 2 O (1 liter) and extracted with ether (250 mL x 3). The extracts such as 05 were washed with H 2 O (χ 2) and brine (x 1), dried (IVlSO 4) and evaporated to give 7.16 g (41.4 mmol, 89.4%) of ethyl 2-azido-ethoxyacetate as a yellowish oil: 1 Hmr (CDCl 3) δ: 1.30 (3H, t, J = 7Hz, -OCH 2 CH 3), 3.3-4.0 (4H, m, -OCH 2 CH 2 N 3), 4.13 ( 2H, s, -COCH 2 O-), 4.23 ppm (2H, q, J = 7Hz, -OCH, CHQ); ir (pure) v: 2100 (N ~) and 10 1750 cm (C = 0 ester). This material was used in the next step without further purification.

2-Azidoethoxyacetic acid 15

EtQ> N3 NaOH_ ^ HQ. N

II cr h o-MeOH II ^ cr 3

O 2 G

To a solution of ethyl 2-azidoethoxyacetate (6.56 g, 37.9 mmol) in MeOH (80 mL) was added 1 n aqueous NaOH (80 mL) and the mixture was stirred at room temperature overnight (17 hours). . After removal of insoluble material, the methanol was evaporated in vacuo and saturated with sodium chloride and washed with ether (30 ml x 3).

The aqueous layer acidified with 3 n HCl (30 ml) was extracted with ether (40 ml x 4). The ether extracts were washed with brine, dried (MgSO 4) and evaporated to yield 4.25 g (29.3 mmol, 77.3%) of ** 1 2-azidoethoxyacetic acid as a colorless oil: Hmr (CDCl 3) δ: 3, 3-4.0 (4H, m, -OCH2CH2N3), 4.22 (2H, s, -COCH2O-), 9.52 ppm (1H, s, 30 -CO2H, replaced by DpCO 'ir (pure) vmax: 2600-3300 (br, -CO 2 H) 2100 (azide) and 1740 cm ~ C = O-CO 2 H). This material was used in the next step without further purification.

35

00 DK 161520B

89 2-Azidoethoxyacetylchioride HV ^^ 3 -.SOCI-> os o a

A solution of 2-azidoethoxyacetic acid (2.09 g, 14.4 mmol) in thionyl chloride (5 ml) was stirred at room temperature for 4 hours. Excess thionyl chloride was removed under vacuum from the water aspirator and the residue dissolved in benzene (10 ml, dried over molecular sieves) was evaporated in vacuo. The oil thus obtained was dried under vacuum (water pump) over NaOH for 1 hour to yield 2.23 g (13.6 mmol, 94.4%) of 2-azidoethoxyacetyl chloride as a colorless oil: 1 Hmr (CDCl 3 : 3.43 (2H, br t, J = 5Hz, -CH 2 O-) 3.78 (2H, br t, J = 5Hz, -CH 2) and 4.50 ppm (2H, s, - COCH20-); ir (pure) v: 2100 (azide) and 1800 cm 1 (-COCI) This material max was used in the next reaction without further purification.

4- (2L-azidoethoxyacetylthio) -1- (paranitrobenzyl-2ll-phenylphosphoranylidene-2ll-acetate) -2-azetidinone) + rfSS9 PYr / c1, 2Cl2,

COPNB COPNB

z 2

To a stirred solution of silver-1 (paranitrobenzyl-2'-triphenyl-phosphoranylide-2'-acetate) -2-azetidinone-4-thiolate (7.96 g, 12.0 mmol) in CH 2 Cl 2 (100 mL), which contained pyridine (1.94 mL, 24.0 mmol) was added at 0-5 ° C under a nitrogen atmosphere a solution of 2-azido-ethoxyacetyl chloride (2.23 g, 13.6 mmol) in CH 2 Cl 2 (20 mL), and the mixture was stirred at room temperature for 2 hours. After filtration of the precipitate, the filtrate was evaporated and the residual oil was purified by column chromatography (SiC> 2, 160 g; eluant EtOAc: CH 2 Cl 2 = 1: 1) to collect 4.216 g (6.17 mmol, 51.4% ) of it in the heading

DK 161520 B

§O mentioned phosphoran as a yellowish foam. This foam was used in the next step. An analytical sample was obtained by crystallization from ChUCL ether (1: 9): m.p. 128-129 ° C (decomp.); ir (nujol) v: j 2090 (-N 2), 1755 (β-lactam) and 1690 cm (thioester); 05 Analysis calculated for C34 H30 N5 ° 7PS: C, 59.74; H, 4.42; N, 10.26; S, 4.69;

Found: C, 59.33; H, 4.49; N, 9.69; S, 5.19; TLC (EtOAc) R f = 0.55.

P-Nitrobenzyl 2- (2-azidoethoxy) methyl-penem-3-carboxylate c> S.

In O toluene - ^ γ · Ρφ3 * * J- in 15 C02PNB Ϊ02ΡΝΒ in 20 A solution (turbid) of the above phosphorane (4.13 g, 6.04 | mmol) in toluene (200 ml) was heated under reflux under nitro- | gene atmosphere for 1.5 hours. After removal of the insoluble material, the solvent was evaporated in vacuo and the residual oil was purified by column chromatography (SiC> 2, 80 g, eluent 5% ether in benzene) to collect 2.44 g (6.02 mmol , 99.6%) of the title compound as a yellowish oil. This oil was used in the next step. Crystallization from Ch 2 C 2 -ether (1: 9) gave an analytical sample: m.p. 88-89.5 ° C; 1 Hmr (CDClip 6: 3.35 (2H, t, J = 5Hz, -OCH2-), 3.47 (1H, dd, Jgem = 16Hz, Jtrans = 2Hz, Cg-H), 3.67 (2H, t , 30 J = 5Hz, -CH9No), 3.85 (1H, dd, J = 16Hz, J = 3.5Hz, Cc-H), 2 3 gem cis' 6 4.73 (2H, ABq, J = 16, 19 C2 ~ CH2), 5.30 (2H, ABq, J = 13.5, 9, -OCH2 Ar), 5.63 (1H, dd, Jtrans = 2Hz, Jcis = 3.5Hz, Cg-H ), 7.50-7.63-8.12-8.27 ppm (4H, A2lB2 ', aromatic Hs); ir (nujol) v: 2100 (-NL), 1785 (β-lactam) and 1695 cm (ester) uv (EtOH) max j; λ: 263 mp (ε 12000), 320.5 mp (ε 9600) TLC (benzene: ether = 1: 1) max

R f = 0.60.

DK 161520 B

SI

2- (2-Aminoethoxy) methyl-penem-3-carboxylic acid 05 I CH AND CH N H2 / Pd-C. r "" \ 2 2 2 3> J-J / -CH2 ^ H2CH2NH2

æ2PNB bo2H

10

A solution of the above azido ester (1.62 g, 4.00 mmol) in dimethoxyethane (50 ml) was mixed with ether (50 ml), Η, Ο (50 ml) and 10% Pd-C (1.62 g; Engelhard) and hydrogenated at room temperature (H2: 55 psi) for 2.5 hours. After filtering off catalyst 15, the aqueous layer was washed with ether (50 mL x 2) and then EtOAc (50 mL x 1). The aqueous solution was lyophilized to give 817 mg (3.34 mmol, 83.6%) of the title amino acid as a yellow powder: uv (Η, Ο) Amgx: 304 mp (ε 5000). This material was purified by HPLC (Waters, g Micro Bondapak Reverse Phase 30 20 cm x 10 mm; eluant 1% CH 2 CN in H2 O) to give 432 mg (1.77 mmol), 44.2% of the title amino acid as a white powder: 1 Hmr (D 2 O) 6: 3.19-3.9 (4H, m, -OCH 2 CH 2 NH 2), 3.54 (1H, dd, Jgm = 16.9 Hz, Jtpans = 1.9 Hz, Cg -H), 3.88 (1H, dd,

Jgm = 16/8 Hz 'Jcis = 3'7 Hz' C6_H) '4.52-4.70-4.83-5.01 (2H, AB type, C2-CH2 O) and 5.77 ppm (1H, dd, Jc-S = 3.6 Hz, Jtrans = 1/9 Cg-H); ir (KBr plate) vmax: 1770 (β-lactam) and 1580 cm cm 1 (-CO₂H); uv (H₂O) vmax: mfJ 5400), 256 mp (ε 3100).

Example 8 2- (2-Aminoethylthiomethyl) penem-3-carboxylic acid (via mercaptide intermediate product)

COOH

35

DK 161520 B

92 2-Azidoethyl methanesulfonate

BrCH2CH2OH - »N3CH2CH2OMs 05 A solution of bromethanol (7.5 g, 60.0 mmol) and sodium azide (5.0 g, 76.9 mmol) in HMPT (30 nil) was heated at 115 ° C for 2.5 hours. The reaction mixture was cooled to 23 ° C and diluted with CH 2 Cl 2 (100 mL). The solids were removed by filtration and CH 2 Cl 2 was evaporated on the rotary evaporator leaving a yellow liquid, 10 which was cooled to 0 ° C and successively treated with mesyl chloride (5.57 ml, 72.0 mmol) and triethylamine (10.0 ml, 72.0 mmol). The reaction mixture was stirred at 0 ° C for 1 hour, then at 23 ° C for 6 hours and poured into H 2 O (300 ml). The aqueous solution was extracted with ether (1 x 200 mL, 4 x 100 mL); the ether extracts were combined, washed with 1 n HCl solution, H 2 O, saturated NaHCO 3 solution and H 2 O, dried over anhydrous MgSO 4 and concentrated on a rotary evaporator to an orange liquid distilled under high vacuum, b.p. 95-100 ° C, 0.3 torr, 5.8 g, 58.5%; ir (pure) vmax: 2005 (s, N3), 1345 (s, SO2-0), 1175 (m, SC> 2-0) cm -1. 1 Hmr (CDClip 6: 20 3.03 (s, 3H, OCH 3), 3.43-3.76 (m, 2H, H-2) and 4.2-4.46 ppm (m, 2H, H-1 ).

2L-Azidoethylthioglycolsyre

N3CH2CH2OMs + NaSCH2COONa - → -> N3CH2CH2SCH2COOH

2. H +

Thioglycolic acid (3.14 g, 34.1 mmol) was treated with 1 n NaOH solution (68 mL, 68.0 mmol) and the resulting solution was stirred at 23 ° C for 0.5 h and treated with a solution of 2 g. -azidoethyl methanesulfonate (5.3 g, 32.1 mmol) in dimethoxyethane (15 ml). The reaction mixture was stirred at 45 ° C for 22 hours, cooled to 23 ° C, washed with CH 2 Cl 2 (3 x 20 mL), acidified with 6 n HCl solution and extracted with CH 2 Cl 2 (7 x 40 mL). The CH 2 Cl 2 extracts were combined, dried over anhydrous Na 2 O 2 and concentrated on a rotary evaporator to an oil which was distilled under high vacuum, b.p. 117-122 ° C / 0.27 torr, 4.2 g, 81.2%. ir (pure) v: 2100 (s, ΓΠαΧ

DK 161520 B

93 N3), 1708 (s, C = O) cm -1.1 Hmr (CDClip 6: 2.7-3.07 (m, 2H, H-1 '), 3.35 (s, 2H, H-1) ), 3.30-3.73 (m, 2H, H-2 ') and 11.81 ppm (s, 1H, COOH).

05 2l-Azidoethylthioacetyl chloride n3ch3ch3sch3cooh (coci) 2 n3ch2ch2sch2coci

To a solution of 2-azidoethylthioglycolic acid (3.33 g, 20.7 10 mmol) in CH 2 Cl 2 (50 ml) was added oxalyl chloride (3.9 ml) and DMF (one drop). The reaction mixture was stirred at 23 ° C for 1.5 hours and the solvent removed on a rotary evaporator leaving a yellow liquid, ir (pure) vmax: 2100 (s, N 3), 1785 (bs, C = 0). Hmr (CDCl 3) δ: 2.6-3.0 (m, 2H, H-1 ') / 3.37-3.73 (m, 2H, H-2') and 3.82 ppm (s , 2H, H-1).

4- (2L-Azidoethylthioacetylthio) -1- (paranitrobenzyl-2 "-triphenylphosphoranylidene-2" -acetate) -2-azetidinone 20- <SA9

. [_2 2 2 3_v I

rT N \ cr— 0 f = PPh3 σ 7 = PPh3

25 COOPNB COOPNB

A solution of silver 1- (paranitrobenzyl-1'-triphenylphosphoranylidene-11-acetate) -2-azetidinone-4-thiolate (15.7 mmol) and pyridine (1.6 30 mL, 19.8 mmol) in CH 2 Cl 2 (200 ml) was treated dropwise (0.25 t) with a solution of 2'-azidoethylthioacetyl chloride (3.64 g, 20.3 mmol) in CH 2 Cl 2 (50 ml). The reaction mixture was stirred at 23 ° C for 1.5 hours and filtered; the solids were washed with CH 2 Cl 2. The filtrate and washings were combined and washed with 1 n HCl solution, H 2 O, 35 saturated NaHCO 3 solution and Η 2 <3, dried over anhydrous Na 2 O 3 and concentrated on a rotary evaporator to give an orange syrup.

A column chromatography (300 g silica gel G-60, eluant EtOAc 94)

DK 161520 B

in CH 2 Cl 2, 0-40% of crude compound, after evaporation of solvent, gave a white powder, 7.7 g, 70%. An analytical sample was obtained after recrystallization from CH 2 Cl 2 ether-petroleum ether, m.p.

150-151 ° C, decomp.

O Analysis calculated for C34 H30 N5 O6 S2P: C, 58.36; H, 4.32; N, 10.01; S, 9.17;

Found: C, 58.64; H, 4.36; N, 10.03; S, 9.25. ir (KBr) vmax: 2100 (s, N3), 1750 (s, C = 0 of β-lactam), 1675 (s, C = 0), 1655 (s, C = 0), 1610 (s, aromatic) and 1440 cm 2 (s, P-Ph).

10 paraNitrobenzyl-2-aminoethylthiomethyl-penem-3-carboxylate rf 2 2 2 3 i - \ -å- ► CH2SCH2CH2N3 O ^ C = PPh. island

I «« «™ COOPNB

COOPNB

20

A suspension of 4- (2'-azidoethylthioacetylthio) -1- (paranitro-benzyl) -2 "-triphenylphosphoranylidenyl acetate) -2-azetidone (4.5 g, 6.43 mmol) in toluene (375 ml) was stirred at 110 °. C for 2.25 hours under nitrogen atmosphere. The reaction mixture was cooled to 23 ° C and evaporation 25 of solution in a rotary evaporator gave an orange syrup.

The purification of pure material was performed on a silica gel column (90 g silica gel G-60, eluent: ether-petroleum ether, 1: 1-3: 2); the pure material was obtained as a yellow syrup (2.2 g, 81%). ir (pure) vmax-2100 (s, Ng), 1785 (s, C = 0 of β-lactam), 1705 cm 2 (s, C = 0 of PNB); 1HMR (CDCl 3) δ: 2.53-2.90 (m, 2H, H-1 "), 3.30-3.67 (m, 3H, H02", H-6 trans), 3.98 ( ABq, Ja_b = 14.8Hz, 2H, H-1 '), 5.32 (ABq,

Ja-b = 13'0Hz '2H' CH2-PhNO2), 5.66 (dd, JH.5 / H_6 cjs = 3.6Hz, JH-5, H-6 trans = 1'9 Hz '1-H' H "5 ^ 7.58 ^ d / JHo-Hm = 8.8Hz '2H' Ho PNB) and 8.19 ppm (d, 3Hm.Ho = 8 / 8Hz, 2H, Hm PNB).

35

us DK 161520 B

95 2- Aminoethylthiomethyl-penem-3-carboxylic acid 05 JZf ^ -®2eeHa "a" 3 - * COOPNB, CCX

To a solution of p-nitrobenzyl-2-azidoethylthiomethyl-penem-3-carboxylate (45 mg, 0.11 mmol) in dimethoxyethane (5 ml) was added ether (5 ml), water (5 ml) and 10% Pd / C (45 mg, 0.11 mmol). The reaction mixture was hydrogenated at 23 ° C under a 45 psi hydrogen pressure for 15 hours and filtered over a Celite pad. The pad was washed with water and the filtrate and washings were combined and diluted with ether. The aqueous phase was separated and washed with ether and lyophilized.

The crude compound (20 mg) was purified by HPLC: 5 mg, 18%; ir (KBr) νmax: 1765 (c = °) 16 1600 cm "1 (b, COO ~); 1 Hmr (D 2 <3) δ: 2.70-3.00 (m, 2H, H-1) , 3.15-3.45 (m, 2H, H-2 "), 3.49 (dd, J = 16.8Hz, y® · ** J6.5 trans = 1 / 7Hz 'H" 6 trans) '3'85 (dd' Jgem = 18'8Hz 'J6-5 cis = 3'4Hz' H-6 cis), 4.05 (ABq, Jg_j;) = 14.6Hz, 2H, H-1) and 5 , 74 ppm (dd, 35-6 cis = 3/4 * "* z 'J5_6 trans = 1'7Hz' 1H 'H" 5); uv \ nax: 307 (ε 4330) '250 (ε 3282)' 25

Example 9 2- (2-Aminoethylsulfonylmethyl) -penem-3-carboxylic acid No.V-CH2Cl2H2CH2NH2

COOH

35

DK 161520 B

96 para-nitrobenzyl 2- (2-azidoethylsulfonylmethyl) -penem-3-carboxylate 05 I5 ^ -CH SCH CH N -MCTBA- I Γ * '' \ CH ^ CH CH «2 2 2 3 Ch 2 Cl 2 2 2 2 3

COOPNB COOPNB

10

A solution of p-nitrobenzyl-2-azidoethylthiomethyl-penem-3-carboxylate (0.36 g, 0.85 mmol) in Ch₂C ^ (30 mL) was cooled to -20 ° C under nitrogen atmosphere and treated dropwise (2 h) with a solution of m-chloroperbenzoic acid (0.147 g, 0.85 mmol) in CH 2 Cl 2 (90 ml). The reaction mixture was stirred at -20 ° C for 0.5 hour, warmed to room temperature and washed with a saturated NaHCO 3 solution and h 2 O. The organic solution was dried over anhydrous Na 2 SO 4 and concentrated under reduced pressure to an orange residue, which was chromatographed over silica gel (silica gel G 60; 9 g; eluent 25% EtOAc in CH 2 Cl 2 / fraction size: 7 ml). Concentration of the relevant fractions gave a white solid; 0.27 g, m.p. 128-131 ° C, 72.6%. About crystal I in sation from acetone-ether-petroelum-ether mixture gave an analytical sample; mp. 142 ° C, decomp .; Analysis calculated for C C ^N ^O₂S₂: C, 43.93; H, 3.46; N, 16.01; S, 14.66;

Found: C, 43.79; H, 3.44; N, 16.02; S, 14.63.

ir (KBr) vma) <: 2110 (Ng), 1785 (C = 0 of β-lactam), 1690 (C = 0 of PNB ester), 1600, 1560 (C = C), 1520, 1355 cm (NO2); uv \ CHCl3: 265 (ε 12884), 333 (ε 8764); 1 Hmr (CDCl3) max 6: 2.95 (2H, m, CHgCHgNg), 3.58 (dd, JH_6_H_5 trans = 2 ' 0Hz 'Jgem = 16.6Hz, H-6 trans), 4.33 (center of ABq, Jg = 13.4 Hz, H-1J) / 4.32 (center of ABq, J = 13.2Hz, H-1 '), 5.33 (center of ABq,

3 f D

Ja ^ = 13.7Ηζ, 2H, CH2 of PNB ester), 5.75 (dd, J ^ _g _ ^ _ g cjs3 / 6Hz, 35 JH-5-H-6 trans = 2'1Hz '1H / H "5 7.60 ^ d 'JHo-Hm = 8.8HZ / 2H' Ho of PNB ester) and 8.22 (d, J ^ m_0 = 8.8Hz, 2H, Hm of PNB ester).

2- (2-aminoethylsulfonylmethyl) -penem-3-carboxylic acid ° 5 s -r "s \ 9 10% pd / c I-Γ \ 9

CH I CH N _- * l · J> “CH SCH CH NH

o 2 L_N 2/2 2 2 3 DME, Et 2 O, H 2 O (/ N 2 2 2 2)

COOPNB COOH

10

To a solution of paranitrobenzyl 2- (2-ethylsulfonylmethyl-penem-3-carboxylate (57 mg, 0.13 mmol) in dimethoxyethane (20 ml) was successively added Et 2 O (10 ml), (10 ml) and 10 ml. % Pd on charcoal (57 mg). The reaction mixture was hydrogenated under 55 psi for 1.25 15 hours and filtered over a Celite pad. The filtrate was diluted with EtgO; the organic phase was separated and the aqueous solution was washed with Et 2 O (twice) and The crude orange colored powder (30 mg) was purified by HPLC; lyophilization of relevant fractions gave the title compound as a white powder; 10.4 20 mg, 29%, h 2 O uv: 313 (ε 4877); ir (KBr) vm: 1720 (C = 0 of β-lactam) and ΓΠ3Χ μ ΓϊιαΧ 1590 (carboxylate); Hmr (DgO) δ: 3.0-3.7 (5H, H-6 trans, CH2CH2NH + 3) 3.90 (dd, JH .6H.5 cls -3.6Hz, Jgem = 16.9Hz, 1H, 25 H-6 cis), 5.45 (center of ABq, b = 13.6Hz, H-11), 4.50 ( center of ABq, Ja b = 13.6 Hz, H-11) and 5.8 * (m, 1H, H-5).

Example 10 Silver 1- (8-trimethylsilylethyl-2L-triphenylphosphoranylidene-2L-acetate) -2-azetidinone-4-thiolate-β-SAg 35 Y 3 / CH 3 CO_CH CH Si - CH3 * Δ * nch3

98 DK 161520B

di-p-trimethylsilylethyl fumarate "Λ" Τ 77. (CH) Si ο ο pyridine 33 Ο

To a cold (-10 ° C) ether (20 ml) solution of 2-trimethylsilyl-ethanol (4.73 g, 0.04 mmol) [H. Gerlach Helv. Chim. Acta 60, 3039 10 (1977)] and pyridine (5.66 ml, 0.07 mol), under nitrogen, were added dropwise (15 min) fumaryl chloride (3.78 ml, 0.035 mol) dissolved in ether (10). mL). The black mixture was stirred for 5 minutes at -10 ° C and for 10 minutes at room temperature. Charcoal was added and the reaction mixture was filtered on a Celite pad. The filtrate was washed with sodium hydrogen carbonate 1% brine (1: 1, 150 ml). The aqueous phase was back-extracted with ether (30 ml). The ether solutions were combined, washed with brine, dried over sodium sulfate, filtered and concentrated under reduced pressure to give a brown solid. This compound was purified on a silica gel pad (30 g, 4 x 5 cm) with benzene 20 (300 ml) as eluent to give an oil (4.855 g, 77%) which solidified on standing: m.p. 33-34 ° C.

Analysis calculated for 4H2804S * 2: C, 53.12; H, 8.91;

Found: C, 53.35; H, 8.91.

1 Hmr (CDCl 3: 6.78 (2H, s, C = CH), 4.26 (4H, m, CH 2 -O), 1.03 (4H, m, CH 2 -Si) and 0.06 ppm ( 18H, s, (CH3) 3Si); vma) <: 1710 (C = O of ester), 1643 (C = C), 1267, 1258, 862 and 840 cm -1 (Si-C).

Trimethylsilylethyl, glyoxylate hydrate 30 ° XI 11 ° 3 L> 21 (CH 3) 2 S * 10 2 3 3 35

DK 161520B

99

A solution of di-p-trimethylsilylethyl fumarate (37 g, 0.117 mmol) in methylene chloride (1.1 L) was ozonated at -78 ° C until a blue color was maintained. Excess ozone was excreted by nitrogen and dimethyl sulfide (2.57 ml, 0.351 mol) was added. The solution was allowed to gradually settle to a temperature of 23 ° C. The reaction mixture was diluted with carbon tetrachloride to 2 liters and washed with 1% aqueous solution of sodium carbonate (500 ml). The organic phase was dried over sodium sulfate, filtered on Celite and evaporated (· ν25 ° 0) to dryness to give 43.9 g of the title compound (97%); ir 10 (pure) v: 3450 (-OH), 1740 (ester, 1255, 860 and 840 cm 2 (Si-C). max 1- (6-trimethylsilylethyl-2l-hydroxy-2l-acetate) -4-tritylthio -2-azetidinone 15, VTr f'101,12 SiCH, _. R-f '"' JZI C02 ^^ i. Jn OH.

CT0 Si (CH) 20

Trimethylsilylethyl, glyoxylate hydrate (4,000 g, 11.6 mmol) and 4-tritylthio-2-azetidinone (4.8 g, 24.96 mmol) were refluxed in benzene (25 mL) in a Dean Stark condenser under nitrogen for 24 hours. The solvent was evaporated under vacuum. The product was chromatographed on a silica gel column (450 g, 8.5 x 14.5 cm) and eluted with ethyl acetate: methylene chloride (1:19) until the title compound started to come out (~ 1.5 liters) and then with ethyl acetate: methylene chloride (1: 9, 2 liters). The fractions containing the title compound were combined and evaporated to dryness to give 5.415 g (89%) of the title compound. Hmr (CDCl 3) 6: 7.80 to 6.70 (15H, m, trityl), 5.23 and 4.90 (1H, 2s, HCO), 4.50 to 4.10 (3H, m, H-3 and O-CH 2), 2.60 (2H, m, H-2), 0.95 (2H, m, CH 2 -Si and 0.1 ppm (9H, s, Si-CH 2); CHCL) v: 3520 (-OH), 1765 (C = 0 of β-lactam), 1740 (C = 0 of w max m 35 ester), 1595 (CH, aromatic), 1257, 860 and 840 cm -Si).

In 1- (p-trimethylsylethyl-2l-chloro-2l-acetate) -4-tritylthio-2-azetidinone in ST 2 SO 2 Cl 2 - STr in oh pyridine *. Cl v (CH3) 3 0 "r / \ / Si (CH3) 3 CO CC> 2 2! 10 j

A solution of thionyl chloride (0.74 ml, 10.37 mmol) in dry THF; (9 ml) was added three times, with stirring, to a solution of 1- (β-ίπ-methylsilylethyl-2L-hydroxy-2f-acetate) -4-tritylthio [2-azetidinone (4.9 µg, 9.37 mmol), pyridine (0.84 mL, 10.38 mmol) and dry THF (40 mL) | 15 at -15 ° C under nitrogen atmosphere. The mixture was stirred at -15 ° C for 2 hours. The precipitate was removed by filtration on a Celite pad and washed with benzene (50 ml). The filtrate was evaporated in vacuo at 30 ° C. The residue was dissolved in benzene (100 ml), treated with charcoal and filtered through a celite pad. Evaporation of the solvent gave a residue which was purified through a silica gel pad (100 g, 4.7 x 11 cm): hexane-benzene (1: 1, 400 ml), ether-benzene (1:19, 1 liter) . Evaporation of the relevant fractions gave 4.64 g of the title compound (92%). Hmr (CDCl 3) 6: 7.30 (15H, m, aromatic H), 5.77 and 5.43 (1H, 2s, CH-Cl), 4.7 to 4.2 (3H, m, H- 4 and 25 CH 2 -O), 2.85 to 2.50 (2H, m, H-3), 1.15 (2H, m, CHg-Si) and 0.06 ppm (9H, s, Si-CH ); ir (pure) v: 1760 (C = 0), 860 and 840 cm 2

o iliuX

(C-Si).

1- (p-trimethylsilylethyl-2l-triphenylphosphoranylidene-2l-acetate) -30 -4-tritylthio-2-azetidinone r ~ T _ £ _► n "STr X — N Cl 2,6-lutidine J — N ρφ

^ Ύ snow) r Y "'" A

35 i02

101 DK 161520B

A dioxane (20 ml) solution of the above chlorazetidinone (4.12 g, 7.568) was treated with triphenylphosphine (2,209 g, 8.424 mmol) and 2,6-lutidine (0.98 ml, 8.424 mmol). The mixture was refluxed for 3.5 hours. hours. The cooled solution was filtered and the white solid 05 washed with THF. The filtrate was evaporated to dryness. The residue was purified on a silica gel column (200 g, 4 x 31 cm) using ethyl acetate-hexane (3: 7, 1 liter; 7: 3, 1 liter) to give the title phosphorane (4.836 g, 83%). ir (film) νm: 1755 (C = 0), 1615 (phosphorane), 850 and 830 cm cm ((Si-C).

Analysis calculated for C 47 H 46 NO 3 PSSi: C, 73.89; H, 6.07; N, 1.81 Found: C, 72.18; H, 6.08; N, 1.83.

SOIL-1- (8-trimethylsilylethyl-2L-triphenylphosphoranylidene-2L-acetate) -2-azetidine non-4-thiolate _ / STr _ / SAg H - + A9NO3 + (nBU) 3H + CF3CO2H ether / H ] Ρφ X 2 S 1, CH 3) 3 X 2 -si | CH 3 1, iol 2 25 l - ^ - trimethylsilylethyl - ^ '- triphenylphosphoranylidene-Z'-acetate) -2-azetidinone (7.64 g, 10 mmol) was dissolved in ether (60 ml). An aqueous solution of silver nitrate (0.5 m, 80 ml, 40 mmol) was added followed by rapid addition (1 minute) of a solution of tributylamine (3 ml, 12.58 mmol) and trifluoroacetic acid (0.154 ml, 0.2 mmol) ) in ether (20 ml). The mixture was stirred mechanically for 19 minutes. The precipitate was filtered, purified with ether (200 ml), triturated in water (70 ml), filtered again and purified with ether (100 ml). The light brown solid was dried under vacuum (water aspirator 10 min and pump 65 min) to give the title compound (6.42 g), ir (CHCl 3) vma) <: 1862 (C = 0, 1630 (phosphorane), 860 and 840 cm 2 (Si-C).

DK 161520 B ι 102; in

Example 11 Silver 3- (11-hydroxy-11-ethyl) -1- (p-trimethylsilylethyl-2ll-triphenylphosphoranylidene-2ll-acetate) -2-azetidinone-4-thiolate 05

OH

Of trans-3-acetyl-1- (p "trimethylsilylethyl-2l-triphenylphosphoranylidene-2l-acetate) -4-tritylthio-2-azetidinone 15 * in JSTr JL STr -f 1. LDA_ VeT ^

Jr PPh3 2- EtOAc J_n pph 0 ^ ~~ SiMe3. ° / N ^ SlMe3 20 2 2

To a solution of di isopropyl ami η (0.80 ml, 5.5 mmol) in tetrahydrofuran (25 ml) at -78 ° C was added n-butyllithium (4.0 ml, 6.0 mmol) with stirring. . After 3 minutes, a solution of 1- (p-trimethylsilylethyl-2, -triphenylphosphoranylidene-2, "acetate) -4-tritylthio-2-azetidinone (3.82 g, 5) was added dropwise over 20 minutes and with stirring. In tetrahydrofuran (40 ml). After 2 minutes, 2.5 ml (25 mmol) of ethyl acetate was added and the solution was stirred for 10 minutes. The cooling bath was removed and 0.2 m hydrochloric acid (58 ml) was added with vigorous stirring. Water and ethyl acetate were added (65 ml each), shaken and separated. The organic phase was washed with water and saturated sodium chloride (60 mL each), dried and the solvent was evaporated in vacuo to give the crude product, 4.1 g.

The product was absorbed from methylene chloride on 20 g of silica gel and placed (dry) in a 120 g silica gel column. The column was eluted with

DK 161520 B

103 ether / hexane 1: 1 (200 ml) and then with ether (500 ml). Evaporation of the solvent from the relevant fractions gave partially purified title compound, 2.17 g (53%); ir vmax: 1755 (β-lactam and ester) and 1710 cm 2 (ketone); Hmr (CDCL) δ: 1.67 and 1.87 peaks for

05 O

II

CH 2 Cl, trimethylsilyl and aromatic peaks; the rest dissolve poorly.

3- (11-Hydroxy-1'-ethyl) -1- (3-trimethylsilylethyl-2ll-triphenylphosphoranylidene-2ll-acetate) -4-tritylthio-2-azetidinone

NaBH4 -J ^ Tr boKv co 3 15 2 2

A solution of the above title compound (2.10 g, 2.60 mmol) in tetrahydro uranium (20 ml) was added to a slurry of sodium borohydride (160 mg, 4.3 mmol) in tetrahydro uranium (10 ml). The mixture was stirred at 23 ° C for 4 hours. Water (30 ml) was added followed by the slow addition of 1 m hydrochloric acid until a pH of 3. The mixture was extracted with ethyl acetate (50 ml). The organic phase was washed with 50 ml of each of 0.1 m sodium bicarbonate, diluted sodium chloride and saturated sodium chloride, then dried and the solvent was evaporated in vacuo to give the crude product.

2.22 g. The product was absorbed from methylene chloride on 11 g of silica gel and placed (dry) in a 44 g silica gel column. The column was eluted with 30 ether. Evaporation of solvent from the relevant fractions gave partially purified title compound, 1.43 g (68%); Hmr (CDCl3): peaks around δ 1 for OH

CH 2 CH-, trimethylsilyl, and aromatic peaks; the rest dissolve poorly.

35

DK 161520 B

104 Spilled v-3-O'-hydroxy-1'-ethyl) -1- (B-trimethylsilylethyl-Z11-triphenylphosphoranylidene-2 "acetate) -2-azetidinone-4-thiolate 05

Ρ »'? H

_ ^ STr A9N03 Me ^ S- {9 __i PPh ~ ^ —Nvs ^ pph7 ^ Ύ 'Si *. ° X A / SiMe3 10 CO 2

A solution of silver nitrate (1.43 g, 8.4 mmol) in water (40 ml) and a solution of pyridine (0.27 ml, 3.35 mmol) and the above phosphorane (1.35 g, 1.67 mmol) in ether (40 ml) was vigorously stirred at 23 ° C for 1 hour. The precipitate was collected by filtration, washed with water and ether and dried to give crude title compound 1.24 g (100%); ir vm · 3420 (OH) and 1750 cm “1 (β-lactam and ester).

20

Example 12 (1'R, 5R, 6S and 11S / 5S, 6R) -6- (11-hydroxyethyl) -2- (2-aminoethoxy-methyl) -penem-3-carboxylic acid (isomer B) - Alternative process 25 f * S V-ch2och2ch2nh2 ^^ co2h (Isomer B) 35

DK 161520 B

105 (VR, 3S, 4R and VS, 3R, 4S) 4- (2-Azidoethoxyacetylthio) -3- (11-hydroxyethyl) -1- (β-trimethylsilylethyl-211-triphenylphosphoranylidene-2-acetate) - 2-a2etidinone 05

OH OH

_ / SA9 <A_ / SCOCH2OCH2CH2N3 0 ^ _N'Y'P * 3 / ”0 ^ -ΝνΦ3 / 1» v / si— I ^ si - 10 \ co2 / s ^ x

Trimethylsilyl chloride (1.54 mL, 11.8 mmol) was added to a stirred slurry of silver 3- (1,1-hydroxyethyl) -1- (p-trimethylsilylethyl-211-triphenylphosphoranylidene-2 "acetate) -2- azetidinone-4-thiolate (isomer B) (2.48 g, 3.34 mmol), imidazole (136 mg, 2.0 mmol) and triethylamine (1.64 ml, 11.8 mmol) in THF (60 ml) The mixture was stirred at 23 ° C for 18 hours, methylene chloride (60 ml) was added, the mixture was cooled to -15 ° C, pyridine (1.32 ml, 16.4 mmol) and β-azidoethoxyacetyl chloride ( 1.43 g, 8.70 mmol) was added and the mixture was stirred at -15 ° C for 0.5 hour, ether (60 ml), ethyl acetate (60 ml) and 1 m hydrochloric acid (20 ml) were added. by filtration and the organic phase was washed with 0.1 m hydrochloric acid (100 ml), 1% sodium hydrogen carbonate (100 ml) and saturated sodium chloride. Concentration of the dried solution afforded the crude title compound as an oil. IR max: 1755 and 1695 cm (1'R, 5R, 6S and 1'S, 5S, 6R) β-trimethylsilylethyl) -2-β-azidoethoxy-30 methyl 6- (11-hydroxyethyl) -penem-3-carboxylate (Isomer B) OH oh

A / scoch2och2ch2n3 X

_W I / —CH AND_CH_N

35 si- CO, XN / S \ 2 i

DK 161520B

106

A solution of the above phosphorane (1.3 g) in toluene (200 ml) was heated under reflux for 3 hours. Concentration of the solvent on a rotary evaporator gave the crude title compound. Chromatography on silica gel (40 g) eluting with increasing 05 relative amounts of ether in hexane gave crystalline title compound, -11 65%. ir v: 1760 and 1700 cm; Hmr showed contamination with a max other isomer.

(1'R / 5R, 6S and 11S, 5S, 6R) -2-6-Azidoethoxymethyl-6- (11-hydroxyethyl) -10-penem-3-carboxylic acid (Isomer B) in 11H-yl ^ CrH2OCH2CH2N3

Or, s O.

NCOo / s ^ v / S \ CO H

2 N 2 20 A solution of anhydrous tetrabutylammonium fluoride (3 mL, 1.5 in rrimol) in THF was added to a solution of the above ester (155 mg, 0.37 mRrvol) in THF (2 mL) at 0 ° C. After 5 minutes at 0 ° C, water (10 ml) and ethyl acetate (10 ml) were added, the mixture was acidified to pH 3 (1 m hydrochloric acid) and the phases separated. The organic phase was extracted with 0.05 m sodium bicarbonate, the aqueous extracts were acidified to pH 3 with hydrochloric acid and extracted with ethyl acetate.

The organic extracts were washed with saturated sodium chloride, dried, concentrated on the rotary evaporator and triturated in ether to give the crude title compound as a solid, 27 mg, 28%. ir vm: 3500, 1785, 1670 cm "1; 1 Hmr (CDCL) δ: max δ 3.30 (3H, d, J = 6.5, CH 2 V), 2.22 (1H, OH), 3 , 1-3.9 (5H, m, CH 2 and H-6), 3.9-4.4 (1H, m, H-1 '), 5.60 (1H, d, J = 1, H- 5).

35

'DK 161520 B

107 (1 * R, 5R, 6S and 1'S, 5S, 6R) -6- (1'-hydroxyethyl) -2- (2-aminoethoxymethyl) -penem-3-carboxylic acid (Isomer B) 05

PH OH

I Γ AND CH N _► | Γ CH AND CH NH

2 2 2 3 0 <i— 2 2 2 2

COH 2 CO 2 H

10

A solution of the above azido compound (150 mg) in THF (15 ml), ether (15 ml) and water (15 ml) was hydrogenated in a Parr shaker in the presence of 10% Pd / C (150 mg) at an initial 15 Hg pressure of 60 psi. After 3 hours, the catalyst was removed by filtration over Celite and the aqueous phase was washed with ethyl acetate and lyophilized to give the crude title compound. Purification by HPLC (Waters, Cg Micro Bondapack Reverse Phase) gave 46.7 mg of pure title compound, which was identical to a previously prepared sample prepared by hydrogenation / hydrogenolysis of the corresponding azido-p-nitrobenzyl derivative.

Example 13 6-Ethyl-2- (2-aminoethoxymethyl) -penem-3-carboxylic acid C2H5Y_ J-Iy ™ 2οοη2οη2 ™ 2

30 O

COgH

0AC_csi_ ^^ "V — f C / ^ X __> * 0Ac

NaHCO J - NH + I + Η Q) 35 Na2 SO3 1 III.

r DK 161520 B; 108 The 1-butenyl acetate (about 1: 1 mixture of cis and trans isomers) was prepared according to P.Z. Bedoukian, J. Am. Chem. Soc. 661,325 (1944).

To cooled (-15 ° C)] (50 ml) was added stepwise 10 ml (11 g, 78.05 mmol) of CSI. The mixture was allowed to gradually rise to 0 ° C over 30 minutes. It was cooled to -20 ° C and carefully poured onto a mixture of water (8 ml), ice (35 g), NaHCO 3 (18.4 g) and 250 ° (6.4 g), vigorously stirred at 0 ° C for 30 minutes, treated with petroleum ether (250 ml) and cooled to -40 ° C. The solvent was decanted and the residue treated with an additional 100 ml

petroleum ether in the same way. The combined petroleum ether extracts were washed with water (30 mL) and dried (Na 2 SC> 4) to recycle L

The aqueous phases were combined and extracted with ethyl acetate (5 x .40 ml). The extract was dried (Na 2 SC> 4) and concentrated in vacuo to give 7.0 g (57%) of a mixture of 28% J

Hi, kp. 82-85 ° C (0.01 mm); Nmr 6 (ppm, CDCl 3) 7.3 (ΙΗ, ΝΗ) 5.92 (0.72 H, d, J = 4.4, 11-H-3), 3.3 (0.28 H, d, J = 1.4, HI-H-4), 3.3 '(1H, m, H-3), 2.24 (3H, s), 2.72 (2H, two q, J = 7), 1.1 (3H, two t, 20 J = 7). vc = Q 1775, 1755 cm "1

Analysis calculated for C C HH ^ NONO:: C, 53.49; H, 7.05, N, 8.91 Found: C, 53.12; H, 6.93; H, 8.85.

25 - ^ OCOCH3 NaSCOCH ^ - ^ S-COCH3 4— NH J— nh

ISLAND

30

11 + 111 IV

35

DK 161520B

109

Sodium thioacetate was prepared by adding thioacetic acid (0.8 mL, 850 mg, 11.2 mmol) to a cooled (ice bath) 1 n sodium hydroxide solution (11.2 mL) under nitrogen. This was added to a cooled solution of JH and HJ 2 (1.57 g, 10 mmol) in water (5 ml) under Ng.

05 The mixture was stirred for 1 hour at room temperature. When an oil separated, acetone (9 ml) was added and stirring was continued for 1.5 hours.

The mixture was concentrated in vacuo to remove acetone and then extracted with methylene chloride. The extract was dried and concentrated in vacuo to give 1.65 g (95%) of crude mixture of 85% trans] V and 15% cis W, bp. 105-110 ° (0.02 mm), 7.1 (1H, NH) 5.53 (0.24H, d, J = 4.5, cis-H-4), 5.12 (0.8H, d, J = 2.4 trans-H-4) 3.34 (1H, to t, J = 7) 2.48 (3H) 1.9 (1H, to q, J = 7) 1.15 (3H , to t, J = 7.

v. 1700, 1765 cm "1, c-o

Analysis calculated for CyH 2 N: 15 C, 48.53; H, 6.40; N, 8.07

Found: C, 48.18; H, 6.47; N, 7.77.

202 -f3O2N ''}} CH2 ~ CO2CH (OH) 2 ^

1-NH> J-N

OOH CHOH

C02PNB

A mixture of] V (1.25 g, 7.2 mmol) and p-nitrobenzylglyoxylate (1.6 g, 7.5 mmol) in benzene (80 ml) was refluxed for 20 hours under a Dean Stark water collector followed by concentration in vacuo to give 3.01 g of rit product. This was filtered over a small amount of silica in chloroform to give 2.8 g (quantitative yield) of a pale yellow oil V containing some solvent, δ 7.9 (4H, m) 5.3 (4H, m) 4.8 (1H, OH) 3.2 (1H, m) 3.37 and 3.33 (3H, two s) 1.8 (2H, m) 1.05 (3H, m) vc = 0 1765, 1700 cm 1. This product

DK 161520 B

110 was used in the next step without further purification.

^ scoch2 soci7 - [/ scoch3 05. 1 * _ 'o ^ “N> ci

° CHOH I

In CO PNB

co2pnb 2 V 1 10

To a cooled (ice bath) stirred solution of V (2.1 g, 5.5 mmol) in dry benzene (10 ml) was added thionyl chloride (3 ml) and the mixture was kept at 5 ° C for 2 hours followed by evaporation under vacuum at room temperature. Excess thionyl chloride was removed by repeated addition and evaporation of benzene and the product was purified by filtration of the benzene solution over a small amount of silica gel to give, after concentration in vacuo, 1.7 g (77%) of a crude pale yellow oil V1, δ 7, 9 (4H, m) 6.0 (1H, s) 5.3 (3H, m) 3.3 (1H, m) 2.7 and 2.3 (3H, two s) 1.75 (3H, m) ) 1.0 (3H, m) from 1700, 1775 cm. The product was used in the next step without further purification.

25 j ^ -C0CH3 p <j> 3 / Vj __ ^ s-coch3 lutidine> rf _ ^ CHCl ^ γ = ρΦ3

CO PNB CO PNB

2 2 30. 35

WE YOU

111

DK 161520 B

A mixture of VI (1.7 g, 4.2 mmol), triphenylphosphine (1.57 g 6.0 mmol) and 2,6-lutidine (5.35 mg, 5 mmol) in dry dioxane (20 ml) was heated. at 55 ° C for 19 hours followed by concentration in vacuo.

The dark red residue was chromatographed on a silica gel column (35 05 g). Elution with benzene ether gave 2.3 g (87%) of V_M_ as a light red oil which was used in the next step without further purification.

S-COCH AgNO_ A * _s Case in 3 --—> ΓΊ »ΎΡ03 ^

COgPNB COgPHB

WE YOU . VIII

15

Mercaptide VIII is prepared from VII by the general procedure of Example 3.

20 25 30 35 112

DK 161520 B

! C1 \ / s. .N / PyΓ 1) 3 J N pa ~ '

O 2) TFA

05 Γ co2pnb

VIII

/ V r \ ^ \ 0A /? * 10 o Ηχγ> ρ03 Δ co2phb IX 15

H2 / Pd-C

"-I> ch2och2oh2k3 ->.

0 \

CO PNB

X d 20 Λ — Τ'χ j-Ι> CH2 ° CW2

XCO_H

25 *

^ XI

Reaction of mercaptide VIII with 2-2-azidoethoxyacetyl chloride according to the procedure of Example 6 gives intermediate IX which can be cyclized and reduced as in Example 6 to give the title compound.

35

DK 161520B

113

Biological data

Representative compounds of the present invention were subjected to in vitro antibiotic screening against 05 different microorganisms. Samples of the indicated compounds were found, after dissolving in water and diluting with nutrient substrate, to exhibit the following minimum inhibitory concentration (MIK) in pg / ml against the indicated microorganisms determined by overnight incubation at 37 ° C by the tube dilution method.

10 15 20 25 30 35 •! 9 i

DK 161520 B

114 MIK in ng / ml

Compound (Example #)

Organism 6 7 8 9 05

Streptococcus pneumoniae A9585 0.03 0.13 0.13 0.5

Streptococcus pyogenes A9604 0.03 0.13 0.13 0.5

Staphylococcus aureus 10 A9537 0.06 0.13 0.13 0.5

Staphylococcus aureus + 50%

Serum A9537 0.5 1 0.5 4

Staphylococcus aureus A9606 0.25 32 16 4 15

Staphylococcus aureus A15097 1 125 16 63

Streptococcus faecal is A20688 4 32 63> 63

Escherichia coli 20 A15119 0.5 2 4 8

Escherichia coli A20341-1 0.5 8 16 32

Klebsiella pneumonia A15130 2 4 8 32 25

Klebsiella species A20468 2> 125> 63> 63

Proteus mirabilis A9900 1 2 4 8

Proteus vulgaris 30 A21559 1 8 16 16

Proteus morganii A15153 4 8 8 16

Proteus Straightening A21203 2 2 8 16

Serratia marcescens A20019 2 2 8 32 35

DK 161520 B

115

Enterobacter cloacae A9659 8 8 32 32

Enterobacter cloacae A9656 2 4 32 63 05

Pseudomonas aeruginosa A9843A 16 63 63 63

Pseudomonas aeruginosa A21213 8 125> 63 63

Hemophilus influenzae ιυ A9833

Haemophilus influenzae A21522

Bacteroides fragile is A20931 _ __ _ 15

Bacteroides fragilis A20929 - 20 25 30 35

Claims (3)

An analogue and method of preparing a peneme derivative of the general formula (I) 5 Y \ _rs I (Alk) -A- (Alk ') -NH 2 CO 2 H 10 and pharmaceutically useful salts thereof Alk is C 12 alkylene, A is O, S or SO, Alk7 is C 2-4 alkylene, and Y is hydrogen or lower alkyl which may be substituted by hydroxy, characterized in that a compound of formula 20 (Alk) -A- (Alk ') -N, N \ P (Q) 3 CO 2 R "wherein Y, Alk, A and Alk7 have the meaning given above, R" is a readily cleaved ester forming group and 30 Q is phenyl or lower alkyl, cyclized in an inert organic solvent at a temperature slightly above room temperature and to the reflux temperature of the solvent, after which the obtained compound is hydrogenated and the obtained compound of formula (I) converted, if desired, to a pharmaceutically acceptable salt thereof. Process according to claim 1, for the preparation of 6- (17-hydroxyethyl) -2- (2-aminoethoxymethyl) -penem-3-carboxylic acid, characterized in that a starting material of formula * DK 161520 B (II) is used as starting material where Y is CH 3 CH (OH), Alk is CH 2, A is 0, Alk 'is CH 2 CH 2, R "is p-nitrobenzyl, and Q is phenyl. Azetidinone derivative for use as a starting material in the process of claim 1, characterized in that it has the formula OY N___, sC- (Alk) -A- (Alk ') -N310 o ^ -NnYP (Q, 11 wherein Y, Alk, A, Alk ', R "and Q are as defined in claim 1. 15