CA1128530A - MONOCYCLIC .beta.-LACTAMS WITH ANTIBACTERIAL ACTIVITY - Google Patents

Abstract

ABSTRACT
A monocyalic .beta.-lactam containing a cis-.beta.-acylamino moiety as in the penicillin and cephalosporin antibacterials is disclosed. These compounds have antibacterial activity against a variety of Gram-positive and Gram-negative organisms.
Intermediates useful for the preparation of these antibacterials are also disclosed.

Description

~Z~i3~ .

B-Lactam~ antibiotics are an impartant group of co~pou~ds in man's struggle against infectious diseases. The most i~poreant B-lactams are the penicillins and cephalosporins which contain another ring sys~em, either thiazene or thiazole, as an intzicate part of the total 301ecule. In general, only bicyclic ~-lactams ha~e ~u~ficlent antiba~.erial activity to be co~mercially useful.
Many monocyclic B-lactams have been reported in ~he literature primarily as degradaeion products of penicillins or cephalosporins or as ~ynthetic precursors for pencillins and cephalos~orin3. ~owever, slgnificant biological acttvity has not been reported for these mono~
cyclic B-lactams. U.S. Patent Nos. 3,943,123; 3,840,556 and 3,920,696, an article ln J. Med. Chem. 18, 625 tl975) and German Patent No.
2437385 are illustrative of this point. One exception to this general rule i~ a monocyclic ~-lactam prepared by ermentation ~nd recent}y reported in J. .4mer. C~em. Soc., 98, 3023 (1976).
~ e have now discovered a n~ monocyellc B-lactam syst~m which is prepared by a totally synthetic method and which possesses good antibacterial activity.
DESCRIPTION OF THE INVENTION
The com?ounds o ehis in~ention are rspresented by the following structural for~ula:

A ~DaO~

? 5 ~ ¦ For~ula I
~y C~O~
wherein A is amino, protected amino or acylamino;
~ is C~2-naloge~, C~2~ io2 ~ Q or C~252 .

1 R ls lower alkyl;
Q is hydrogen, lower alkyl, or halo;
Y 1~ S~ E or hydroxy;
~ ig hydrogen, lower alkyl, tr æ luoro~e~hyl or phenyl, unsubstltuted or substituted with one os two substltuents selected fro~ the group consistlng of lo~wer alkoxy, lower alkyl, halo, and nitro; and M is hydrogen, a carboxylic acid proteetl~e ~er group, or a pharmaceutically accepta~le ca~ion.
The terms lower alkyl, lower alkylthio and lower alko~y used ~ithin th~s entire dlqclo~ure refers to alkyl groups containing one to ~ix carbon atoms. The term halogen or halo includes fluorine, chlorine, bromine and lodine.
Compounds of Formula I where ~ 1R chloromethyl, bromomethyl or lodomethyL and E i9 methyl or phenyl are a preferred grouy.
~nother preferred group of co~pounds Ls tho~e compounds whlch have antibacterial acti~ity. This group of co~pounds is those of Fo-~lnula I where A i9 acylamino, Y i3 SCOE and M i9 h~dro~en or a phar~aceutically acceptable catLon.
Within the term acyla~lno, acyl refers to any acyl group ~0 used withi~ the semisynthetic cephalosporin and penicillin art.
Examples of many of these well know~ groups are set forth ~n "Cephalo~porins a~d Penicillins", ed. Flynn, Academic Preqs 1972;
U.S. Patent ~o. 3,95~;424 and 3,953,436. Preferred ~cyl groups are presented by the general formula~:
~5 ~'-CH~O- Y'-C~ r CO- , or Z-S(0)3C82CO-A' ~here ~ thienyl, furyl, cyclohexyl, cyclohexenyl, cycloh~Yadienyl, phenyl or phenyl substituted with one ~ il5~
1 ~ or two substltuents ~eleceed from the group consis~ingof lower alkyl, lo~er alko~yl, hydroxy9 hydro~ymethyl, halo, nitro, amino, aminomethyl, mercapto, lower alkylthio, tr~fluoromethyl, ureido, formamldo, and carboxymethylamlno;
A' is amino, hydroxy, ~ormyloxy, carboxyl, sulfo' or .
(when the a-hydrogen i9 absent) meehoxyimino or oximino;
Y' is cyano9 azido, phenyl, pheno~y, 2-aminomethylphenyl or a 5 or 5-membered heterocyclic ring containing carbon and 1-4 heteroatom~ selected from the group consisting of nitrogen, oxygen and sulfur;
Z i8 phenyl, pyridyl, lower alkyl, trifluoro~ethyl, trifluoroethyl, or cyanomethyl; and n i~ 0, 1 or 2. .
The 5- or 6-membered heterocycles include thienyl; ~uryl, thiazoyl, lsothiazolyl, oxadlazolyl, thiadlazolyl, triazolyl, eetra-zoiyl, sydnone, pyridyl, pyri~idyl and the like. Each heterocyclic group may be uns~bstltuted or substituted with one or two sub~tituents selected f~om louer alkyl, halo, hydroxy, nitro, amino, lower alko~y, aryl such as phenyl, lower aralkyl and the like.
Particularly preferred acyl groups lnclude the following examples:
phenylacetyl ~ ~ydro~yphenylacetyl u-formyloxyphenylacetyl ~ ~;
~-amicophenylacetyl ~5 ~-aml~o 4-hydro3yphe~y}acetyl -ami~o-4-hydroxy-3-fluorophenylacetyl ~rifluoromethylmercaptoacetyl methylmercaptoacetyl methylsulfo~ylacetyl ~ 2,2,2-~rifluoroethylsulfinylacetyl

2~353~) ~
cyanoacetyl cyanomethylmercaptoacetyl -carboxy-2-thienylacetyl a-carboxy-3-~hie~ylacetyl . a-carboxyphenylacetyl -sulphophe~ylacetyl

3-3ydnoneacetyl 2-thienylacetyl l-tetrazolylacetyl phç~oxyacetyl

4-pyridylmercaptoacetyl (2-amino~ethylphenyl)acetyl ayn-a-methoxyimino-t2-furyl)acet a-o~imlnophenylacetyl 2,6-dimethoxybenzoyl - .. ;

~5 '' ' , .

4 _ s~o 1 The ter~ "a carboxglic acid protective ester group" refers to those ester groups which are commonly employed to block or protect the carbo~ylic acit functionality whlle reactions are carried out on other functional grou~s within ~he molecule. The term has acquir~
a definite meaning with$n the 3-lactam and organic chemical art~
and many u~eful group9 within this term are known in ehe art. These protec~i~e groups are knowu for the ease with ~hich they may be cleaved to regenerate the carboxylic acid group. Cle2vage can be arfected by known methods including hydrolytic and hydrogenatlon ~o methodg~
Rnown ester protecting groups include lower alkyl such as methyl, 2,2,2,-trichloroethyl, ~-iodoethyl, C4-C6-tert-al~yl, such as t-butyl, C5-C7-tert-alkenyl, C5-C7-tert-alkynyl, Cl-C6-al~moylmethyl, N-phthalimidomethyl, benzoylmethyl, halobenzoyl~ethyl, methylbenzoyl-methyl, methanesulfonylbenzoylmethyl, phenylbenzoylmethyl, benzyl, p-nitrobenzyl, p-metho~ybenzyl, benzhydryl, trityl, trimethylsilyl, trie~hyls~lyl a~d the llke. The choice of which ester group to use is well within the ability of one sk~lled in the art. Factors which are considered include what subsequent reaction conditions the group must withstand and what conditionq for removing the protectin~ ester is desirable. Groups which are removed by treatment with trifluoro-acetic acidj hydrogenatlon or zinc dust and acetic acid have been preferred ~c the art when a B-lactam is fused to a six-me~ber ring and are fount to be particularly useful in this inventiou. The choice~
of the protecting group is not critical to our inventior. since the novelty of our i~vention lies within the new monocyclic nucleus and not the ester substituents.
"Protected amino" is a term well known in the art. It refers to zmino groups which ha~e been masked by another grou? so as to protect them during subsequent chemlc~l reactlons a~d then the ~2~3S30 masking group can be removed to generate again the desired amino moiety. ~a~y groups are know~ and used for this purpose within the penicillin, cephalosporin, and peptide synthetic arts. E~amples of these include, t-butoxycarbonyl, trichloroetho~ycarbonyl, benzylox~-carbonyl, p-methoxybenzylo~ycarbonyl, p-nltrobe~zyloxycarbonyl, isobornyloxycarbonyl, trityl, methyl acetoacetate adduct and the like ~hich arç monovalent protecting groups. Divalent protecting groups lnclude phthaloyl, succi~yl3 maleyl, and the 4,5-diphenyl-4-sxazolin-2-one group. Preparation and removal of the 4-oxazolin-2-one group 0 i5 taught in the art; J ~. Chem., 38 3034 (1973). The choice of the protecting group depends on various factors including the subsequent chemical reaction conditions and the desired conditions for removal of the protecting group. However, thls choice is within the ordinary abillty of one skillet in the art. Again the choice of the amino ~rotecting group i~ not critical to our invention for the same reasons g ven above regarding the carboxyl protecting group.
The above definition of ami~o a~d carboxyl protecting groups i9 not in e~ded to b~ e~haustive. A persou skilled in the art ~nows the purpose of these groups and is able to properly choose from the groups kaown and described in the art. ~any articles acd books have described the sub~ect of protecting reactive groups, for example J. F. W. McOmie, "Protective Groups in Organic Chemistry", Plenum Press, 1973.
The term "pharmaceutically ac~eptable cation" is also a well kuown term in the art. Many bases are known a~d used to prepare ~5 s21ts of carbo~ylic 2cids for pharmaceutical for~ulations. These salts have imyroved properties, such as ~olubility, over the free acids. Examples of useful cations include alkall metals such as sodiu~ and potassiu~, alkali earth metals and ammonium ca~ions fro~

inorga~ic or organic amine bases. These salts are prepared by standard meehods from the appropriate base and the carboxylic acit.

3~

Also included within ehe scope of this invention is the salts of other acid or base moietie~ present in ehe compounds, for example, within the acyl group or when A i5 a~ino. Salts of base moieties are prepared from well-know~ inorganic and organic acids used in the field such as maleic, fumaric, acetic, propionic, ~artaric, citric, hydrochloric, hydrobromic, sulfuric, cyclohexyl-sulfamic and phosphoric acids and ~he likç. These alts are all pre-pared by standard methods kno~ and used in the art and readlly apparent to one skilled in the art.
The compounds of this invention may exist in hydrate or solvate form. The amo~nt of water or solven~ may vary. These ~arious forms of the compounds of this in~ention are also part of the invention disclosed and claimed herein.
The compounds o~ this lnvention where A is acylamino and M is hydrogen or a pharmaceutically occeptable cation have anti-bacterial activity agalnst Gram-positive and G~am-~egative or~anisms.
Minimum inhibitory concentrations (MIC's) against a variety of bacteria is showu in Table 1 fDr representat~ve compounds. Data for a standard antibacterlal agent, cephalothin, is included. Anti-bacterial activity is also observed when the compounds are tested 2~
in a standard in vivo screening test.
The active compounds or their salts can be formulatet into phar~aceutical compositions useful for the treatment or prevention of bacteria} infections in war~-blooded ~ammals such as man. For exa~ple, the salts of the activity compounds can be dissolved in sterile ~ater, ~5 - sterile normal saline and the like to give a liquid pharmaceutical for~ulation which can be admi~istered pare~terally to the subject.
The compounds can also be for~ulated~into forms suitable for oral administration in the same ma~ner as oral penicillins and cephalo-sporins. Daily dosages depend on various factors including the .
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TABIE II

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R' t~ ~12B
o~N~<~ C E
COC)H

Com~ound R' B }~

C~50~H2 ~ C~3 2 . C~HsC~2 CH3 3 2, 6- (CX3O~ 2~6~I3 Br . 3 4 Thienyl-C}I2 I CH3 S Thienyl-CH2 Br C~3 6 Thi~nYl~C~2 Cl CH3 7 Thi2nyl-CH2 OTs ~x3 8 Thienyl-CH2 1 6 5 9 C6H~jCH(OH) I C~3 .10 C6H5C~ 2) I CH3 11 C6H5~2~ . Br CH3 12 C6E5CA(COOA) Br C~A3 ~S

~30 7b -~. ' ' ! I
3~
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I severity of the infection and the age and weight of the sub~ect.
In ~eneral, daily dosages ran8e from about 1-5 g which may be divided into smaller unit doses if desired.
The compounds of this invention where A is amino or pro-tected amino and/or ~ is a carboxylic acid protecting ester group are useful as intermediates for the preparation of the active compounds.
When A is protected am~no, removal of the protect:ing group gives the free amino group which can be acylated to give, after re~oval of any protecting groups, the antibacterial agents.

The compou~ds ~ithin this inven~ion where Y is hydroxy are also ~seful as intermedlates for the preparation of the antibacterial agents disclosed herein.
The compounds of this invention are novel monocyclic B-lactams which are prepared by a totally synthe~ic route. The key starting material is methyl ciR-1-(2,4-dimethoxybenzyl)-3-szido-4-oxoazetidine-2-carboxylate tl). This compound is prepared in good yield H H
- _ COOC~3 ~3 - ~
1I DMB ~ 2,4-dimethoxybenzyl 0~ _ N \

via a ketene-imine cycli~ation reactlon.
It is reatily apparent that conversion or compound 1 into the compounts of For~ulae I involves modification of the substituents at positions 1, 2 a~d 3. ~hree different approaches ~or perfor~ing these modifications are outlined in Schemes I, II and III. However, a person skilled in the art will also appreciate that these modifications can be carried out via a ~ariety of methods and in various sequences.

~:~2~S3~

1 The reaction sequence set forth in Scheme I i~volves first the reduction or the azido molety of compound 1 to an ami~o group. The reductisn cac be affected by catalytic or chemical methodj such as zinc and acetic acid. The amino gronp is blocked with a protecting group. Preferred protecting groups in this sequence of reaction3 are those which are re~oved by treat~ent with trlfluoroacetic acid. Exa~ples of ~uch groups include the lsobornylo-~y-carbonyl and the t-butoxycarbonyl groups. The use of the isobornyloxy-carbo~yl as an amino protecting group is descrlbed in Che~. Phar~. Bull., 0 20, 1017 (1972~. The protected amino derivative 2 is treated with a hydroxyl radlcal protucing agent, such as potassium persulfate, ~hich cleaves the dimet~o~ybenzyl group to give derivative 3. Reduction of the ester group with sodium borohydride ~ives the alcohol which is treated with a substituted benzenesulfouyl chloride, for example tosyl chloride, or with an alkanesulfonyl choride, for e~ample mesyl chloride to give the sulfonate derivative 4 Compound ~i9 treated with a halide salt such as LiBr, ~aI, or ~iCl to gi~e the halo derivative. Addition of an ester of glyo~ylic acid gives alcohol compound 5~ Ben~yl, methyl or ethyl esters which hydrolylyze with weak base or benzhydryl (diphe~ylmethyl) wnich i~ cleaved by trifluoroacetic acid are particularly useful, The addltion reaction can be af'ected by acid catalysis with boron trifluo-ride and the like or an ~nionic additio~ method which involves 8enerating the ~-lacta~ nitrogen auio~ by ~reat~e~ with a stro~g base such a~ butyll~thium. Treatmeut of ~ w~th thio~yl chlor~de a~d then with the ~alt of a thiolcarboxylic acid such as potassium thiolacetate gi~es ~ Removal of the amino protecting group by treat~ent with tr~fluoroacetic acid gives compound 7 ~here R is an ester protecting group or hydrogen ~hen the e ter protecting group is on2 ~hich is r~movable with t_ifluoroacetic acid such as benzhydryl.

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- 9a -1 Acylatio~ of 7 by standard ~ethods followed by removal of a~y protecting groups gives the a~tlbacterial compounds of this in-vention.
The active compounds where ~ ~f Formula I is the methylene alkyl or arylsulfonate substitue~ts can be prepared as outlined in Scheme I by elimlnation of the halide salt displacemen~ reactlon; that is, the sulfonate deriva~ive ~ is react~d ~ith a glyoxyla~e ester and -~
the product i9 carsied forward as described above.
An alternative sequence of react~ons to prepare ~he active ~0 compounds is illustrated i~ Sche~e II. The azido-~wlactam 1 is con-verted to co~pound 8 by removal of the dimethoxybenzyl group, re-duction of the ester to the alcohol and conversion of the alcohol to the sulfonate derivative such as the p-toluenesulfo~ate. These three reactions use the same general procedures which are set forth above in the discussion of Scheme I. The azldo group of co~pound 8 is reduced by cbemical or ~atalytic hydrogenation to give the ami~o-B-lactam which is acylated with the desired acyl moiety to give 9.
Displacement of the ~ulfonate substitueut with halide io~ followed by condensation ~ith a~ ester of glyoxyl~c acid, both by procedures given above, yields derivati~e 10. Conver9io~ of the hydroxy group in 10 to chloro is efected by treatment wlth thio~yl chlorlde or si~ilar reagent. The chloro deri~ative is reacted with a salt of a tb~olcarbox71ic acid such as potassium thiolacetate to give, after re~oval of any protecti~g groups by standard metXods, the active co~pounds such as 11. Agai~, if a 2-methylsulfonate derivative is desired the halide displaceme~t reaction ~s omitted fro~ the sequence.

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SC~IE`IE II

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L213S3~

5cheme III prese~ts another ~equence of reactions which differs from those presented in Schemes I and II in that the azido group i9 not reduced to an amino group until the desired modifications at positions 1 and 2 have been co~pleted. Therefore, compound ~ is converted i~to compound ~ by reactions previously outlined in regard co Schemes I and II. The azido group is reduced to an amino deri~ative ~hich is acylated with the desired acyl group. Any protect~ng groups are removed by standard methods to give the novel antibiotic agents.
Acylation of the 3-amino-2-azetidinone compounds of this O in~ention is effected by standard methods. The carboxylic acid group which will be the car~onyl group of the acyl moiety is activated by known methods including mi~ed anhydride, activated esters, and acid halides. In addition, use of coupling rea~ents such as dicyclohe2yl-carbodiimide and carbonyldiimidazole is a possible method of acylation.
L5 During the acylat~on any sensltive group in the acyl moiety, ~or example hydroxy, amino or carboxyl, can be protected by a standard protecting group such as those described previously. At the appropriate time, which was suggested in the above discussion of preparatlon of thesé compounts or at such other time uhich would be readily apparent to one skilled in the art, the pro~ectlng group can be removed.
The sidechaln moiety attached to the nitroge~ of the S-lactam ring contains an asymmetric carbon thereby giving rise to optical lsomers. In addition~ the ~-lactam rin~ syst~ is formed as a mi~ture of d a~d 1 optical isomers. Separation of isomers is possible by standard methods of fractio~al crystallization. It is to be under-stood that each separate diastereo~er as well as diastereo~eric ~ixtures are ~ithln the scope o thls application.
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SCXE~E III
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Yarious acyl sidechalns which are particularly useful also contain an asymmetric carbon ato~. It is understood that each optical isomer separately and as well as mixtures of the iso~ers are withi~ the scope of this inventlon. It has been found chat the r-isomer is particularly useful and therefore is a preferr d iso~er as with the phenylglycyl or mandelyanino contalning compounds.
~he startlng materlals necessary to prepare the compounds - are commercially available, prepared by know~ nethods or described herei~.
0 The ~ollowlng examples are presented to illustrate general methods of preparing the compounds of this invention to one skilled in the art ant are not to be construed a~ limitatve of tne ~cope thereof. All te~peratures are given in degrees Centigrade.
.

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t ~2~53 Methyl N-(2~4-dimethox~benzyl)iminoacetate To a mix~ure contalning 16.82 g (0.101 mol) of 2,4-dimethoxybenzylamine and anhytrous magnesium sul:Eate in 150 ml of methylene chloride at 25 i~ added a solution of 10.05 g (0.114 ~ol) of me~hyl glyoxylate in 20 ml of methylene chlor:Lde. The reaction mixture is stirred at room temperature overnight (15 hours) and then is filtered and the solve~ts are removed in vacuo to afford the imine as a dark ora~ge gum.

Isobornyl chlorofor~ate Into a~ argon flushed flask is placed 82 ml (100 mmol) o a 12.5~ phosgene ln benzene solution and 100 ml of ether. The solution is cooled to 0 under argon and treated dropwise over a one-hour period with a solution of 11.7 8 (76 mmol) dl-isoborneol and 6.7 ml (33.7 mmol) pyridine iu 50 ml ether. The solution is allowed ~o war~ to room temperature, stirred 2.5 hours, and then filtered. The solid is ~ashed with ether and the filtrate is evaporated in vacuo to give 15.25 g of product.
PREPARA IO~ 3 ~ethyl cis-3-azido-1-t2,4-dimetho~ybenzyl)-4-oxoazetidine-2-. . . ~
carboxYlate (1) Method A:
To a solution of 15.1 g (0.149 mol) of a2idoacetic acid in 130 ~1 of anhydrous methylene chl~ride at 0 (ice bath) is added dropwise 21.0 ml (0.15 mol) of trifluorQaceeic anhydride. This mdxture ij ctirred a 0 for 15 ~inutes and then 20.8 ml (O.lv mol) or triethylamine i~ added dropwise. S~irri~g is continued fvr an addi~ional 45 minutes and then the entire reaction mixture is trans-ferred u~der argon into an additional funnel which is covled externally ~2~3S3'~

.

1 by dr~ t ce. The addicion funnel is attached to a flask con~aining the imine fr Preparation 1, anhydrous methylene chloride (200 ml), and eriethylami~e t20.8 ml, 0.15 mole). The solution of the mixed anhydride is added dropwise fr~m the additional funnel to the solution of imine at 0. Stirring is cont~nued ae 0 for 1 hour and theu the dark raact~on mixture is transferret to a separatory funnel and washed with water, aqueous NaHC03 and brine a~d then dr ed over anhydrous magnesium sulfate. The solvents are removed in vacuo and the residue is chromatographed on 300 g of silica gel (70-230 mesh) affording an off-white solid which ia further purified ~y trituration with ether to give 14.45 g (452) of the title product as a white solid; tlc: benzene: ethyl acetate tl:l), silica gel GF, R - 0.64. Recrystallization frcm ethyl acetate-hexane affords an snalytical sample, mp 82-84.

~ethod B:
.. . . . .
A solutioa of 1.6 g (9.55 mmol) dimethoxybenzyla~ine in

5 ml of methylene chloride is rapldly added at 0 to a solution of 1.06 g (10 mmol) reshly tistilled methyl glyoxylate in 15 ml CH2C12.
A slight exother~ occu~red and water droplet3 appeared. ~lagnesium sul4ate (5 g) is added and th~ mixture stirret at 0 for 2 hours.
Fresh magnesium sulfate (1.0 g) is added, the magnesium sulfate removed by filtration under argon and washed with a minimum of methylene chloride.
To a solution of 3.8 g (36 mmol) of azidoace~ic acid ~pumped in high vacuum 3 hr) i~ 125 ml of methylene chloride is added 10.6 ml (76 m~ol) of triethyla~ine ~ith coollng. Magnesium sulfate (3 g) is added, the mixture stirred 10 minu~es at room tempera~use, filtered under argon and washed with 2S ml me~hylene chloride.
The azidoacetic acid solution is added at 0 ~o the imine, sufficient methylene chloride is added to bring the toeal volu~e eo 1~ 3~1 1 200 ~1, the sslution is cooled to 0 under ~rgo~ and 5.3 ml (38 ~mol) trifluoroacetic a~hydride added slowly over 30 m:~utes with vigorDus stirring and cooling. The mixture is stirred for 1 hr at ~, allowed to warm to room temperature; transferred to a separatory funnel;
~ashed with water, 5Z ~a~C03, 2~ phosphorlc acid and 5~ ~aHC03, dried o~er ~agnesium sulfate-charcoal; filtered cmd the filtrate is retreated t-~ice with charcoal and evaporated to clryness. The residue is dissolved in a minlmum of ether and stored at -20 to allow crystallization. The crystalline mass is isolated and washed with cold ether ~o give 1.9 g (64Z) product, mp 79-80.5.
Method C:
; A solution of 1.6 g of ~,4~dimethoxybenzylamine in 15 ml of methylene chloride is shaken with a~ excess of magneisum sulfate then reacted with 1.05 g of methyl glyoxylate in 2 ml of methylene chloride at 25 (room temperature) overn~ght. The mixture is filtered, stripped a~d degassed with argon.
A ~olution of 1.5 g of azidoacetic acld in 25 ml of methylene chloride is coolet to 0 then re~cted with 1.3 ~1 of oxalyl chloride with 1.2 ~1 of pyridine in 3 ml of methylene chloride at 0.
Argon is passed through thP mixture which is stirred for one hour.
The imine from above is taken into 20 ml of methylene chloride with 4.15 ml of triethyla~lne. The solution of azidoacetyl chloride is added dropwise at 0. After one hour at 0 the mlxturs i5 washed with water, sodiu~ bicarbonat~ solution, and brine, drled a~d stripped. After passi~g o~er a sil~ca gel colu~n with methylene chloride the yield is 1.31 g of the desired compound.
PREP~RATlON ~
cis-3~zido-4-oxo-2-azetidinylmethyl tosylate ~lethyl cis-3-azido-1-(2,4-dimetho~ybenzyl)-4-oxoacetidine-2-arboxyla~e ls reac~ed with potassium persulfate and sodium monohydrogen S~

phosphate according to the procedure of Example 4 co give methyl cls-3-a2ido-4-axoazetidine-2-car~oxylate. The methyl ester of this product is reduced by treatment with sodium borohydride according to the procedure of Example 5 to give the methyl alcohol derivative.
The alcohol is converted into the title c~mpound by treatme~t ~ith p-toluenesulfonyl chlor~de according to th procedure of Example 6;
mp 77-78.
E~A~E 1 ~ethyl cis-1-(2,4-Dimethosybenzyl)-3-amino-4-oxoazetidine-2-carboxylate A mixture containing 10.0 g (0.312 mol) of methyl c_s-l-(2,4-dimethoxybenzyl)-3-azido-4-oxoazetidlne-2-carboxylate, 1.0 g of 10% palladium on carbon, and 200 ml of ethanol ls hydrogenated for 2 hrs at 40-45 at 60 p9i of hydrogen. The reaction mixture i9 allowed to cool to 25 and is filtered through filter-aid. After removlng the solvents in vacuo a clear, yellow gum of the title product i9 obtained.
E~hMPLE 2 Methyl cis-3-t-Butoxycarbonylamino-2-(2,4-dimetho~ybenzyl)-4-oxoazetidine-:~-carboxyl~te ` A solution of 5.5 g (18.8 mmol) of methyl Ci5 3-amlno-l-~ (2,4-dimethoxybenzyl)-4-o~oaz~tidine-2-carboxylate in lO0 ml of dry toluene is cooled to -78; 2.5 ml (18.8 mmol) of triethylamine ls added followed by rapid addition of 35 ml (42 mmol) of a 12% solution of phosgeue in benze~e. The mixture is s~irred 15 min at -78, 3 hr at -45 (acetonitrile-dry ice), then wa Ded to room temperature and con-centrated to half volume in vacuo. To the resulti~g solution is added 50 ml of t-butanol and the mixture is stirred at room temper~ture over~ight. The solvents are removed in vacuo, the residue is dlluted with ethyl acetate ant filtered. The filtrate is tsansfer~ed to a separatory fu~nel and washed with 5% ~a~C03, 5% HCl and brine; dried over magneisum sulface and evaporated to dryness. Recrystalli~ation -i .
of the crude, c~yqtalllne product affords 3.8 g (52~) of the title compound. Recrystallization from ether giYes an analytical sample.
EXAMP~E 3 Methyl cis-3-isobornylo ycarbo~ylamino-1-(2,4-dimetho~ybenzyl)-4-; oxoazetidine-2-carboxylate (2) A solution of 11.5 g (53.7 mmol~ of isobornyl chloroformate ~n 75 ~1 methylene chloride, is cooled to -78 in an argon flushed flask.
To thi~ solutio~ is added dropwise a m~ture of 7.75 g (26.3 mmol) of the 3-amino product from Example 1 and 3.4 g (26.3 m~ol) of diisopropylethyl amine in 150 ml ~ethylene over a 1.5 hour period wlth cooling to 78.
The reaction i9 stirred at -78 ~or }-3 hourq and then allowed to stand overnight at -25. To the solutlon is added 10 ml of cold lN E2S04 and the organic solvent is removed. The residue is dissolved in ethyl acetate which is then washed with two portions`of cold lN H2S04, two portions aqueous ~a~C03 and 5aturated NaCl. The dried solution i9 evaporated and the residue ls chromatographed on si~ica gel with a 8radient of OZ to 15% ethyl acetate ~n methylene chloride as eluant to give 9.7 g of product.
EXA~PLE 4 ~ethyl cls-3-Isobornylo~ycarbonylamino-4-o~oaze~idine-2-carboxylate (3) ~

A degassed solution of 4.75 8 (10 mmol) of the product ~rom Example 3 in 128 ml acetonitrile is heated to reflux. To the refluxlng solutlo~ is added in ~i~ portions o~er a period of one hour a degassed solutio~ o 10.81 g (40 ~ol) R2S208 and 5.36 g (20 mmol) Na2HP04 7~20 in 200 ~1 water. When tlc analysis indicates the raction is co~plete, the solution i~ cooled, the organic sol~ents are e~aporated i~ ~acuo and, after the addition of water, the aqueous pnase is e~tzacted ~tith ethyl acetate. The dried extracts are concentrated and the residue ls chroma~ographed on 8~1ica gel with a gradient of 0% to 50% ethyl acetate in benze~e as eluant to give 2.57 g (79%) of ~he title co~pound.

S3~.

1 E~U~PLE 5 ~.
cis-3-Isobornyloxycarbonylamino-4-oxo-2-azetidinylmethyl alcohol .
A 301ution of 2.5 g t7.7 mmol) of the product from ~xample 4 in 154 ml retr~hydrofuran and 17 ml water u~der ,argon is cooled to 0 and treated with a solution of 582 mg (15.4 mmol) of ~aB~4 in 40 ml cold water. The reaction iq stirred for 1-2 hour~ at 0 and ~hen at -25 overnigh~. E~cess reagent is destroyed by the addition of 2 ml glacial acetic acid. The organl~ solvent i3 removed, additional water i9 added and the aqueous solution is extracted with ethyl acetate.

The extracts are washed wlth sali~e Rolution, dried and evaporated to a residue which is recrystallized fro~ ethyl acetate/etherthexane;
1.42 8 (63%) mp 152.5-154.
E.~AMPLE 6 cis-3-Iqobornyloxycarbonylamino-4-oxor2-azetidinylmethyl tosylate (~
_ A solut-lon of 1.185 g (4 mmol) of the alcohol product of Example 5 in 7.0 ml pyridine under argon i9 cooled to Oq and then 1.525 g (8 mmol) p-toluensulfonyl chloride in 2.4 mt pyridine is added. The reacti~n is stirred at 0 until tlc analysi6 indicates that the reaction is complet~t. To the mixture is added 0.38 ml 8;%
lactic acid. After stirring 1 hour at 0, the reaction is pouret into ethyl acetate and the resu}ting so}utlon is washed twice with water, each of the following: lN H2S04, saturated ~a~C03 and saturated NaCl. The dried solution is evaporated to give the ti~ie product; 2.0 g (100%).
E3~hMPLE 7 c~s-3-Isobornyloxycarbonyl~mino-4-oxo-2-azetidinylmethyl bromide To a mixture of 326 mg (3.75 mmol) LiBr in 4.5 ml dry dimethylfor3amide is added 338 mg (0, 75 mmol) of the tosylate of Exa~ple 6. The mixture is degassed wlth argo~ and heatet to 60 for 4 ho~rsO The reaction is poured into ethyl acetate and washed - }8 -~53~

1 well with water a~d saturated ~a~l. The dried solution ls evaporated ~o give 75% yield of the title compound.
EY~h~PLE 8 Benzhydryl ~-(cis-3-Isobornyloxycarbonylamino 2-bromomethyl-4-oxo-l-azetidinyl)--hydrp~yaceta~e.
~
The bromo compound of Example 7 (800 mgj 2.23 ~mol) is dissolved in 20 ml tetrahydrofuran, cooled to -78 under argon, and treated with 1.2Z ml (2.4 mmol) of 1.97M butyllithium i~ hexane.
After stirring for 30 minutes at ~78, a solution of 577 mg t2.4 mmol) be~zhydryl glyoxylate in 5 ~1 tetrahydrofuran is added. The reaction is stirred 2 hours at -78, quenched with a cold Na~zPO4 solution, and extractet with ethyl acetate. The extracts are washed with saline, dried and evaporated to give the title product.

Benzhytryl (ci~-3-Isobornyloxycarbonylamino-2-bromomethyl-4 oxo-1 c: - . .
L~ l-azetidinvl)thioacetoxyacetate (6) To a cold (-10 with CC14/dry lce) solution of 943 mg (1.57 mmol) of product fro~ Example 8 in 20 ml dry tetrahydrofuran a under argon is added 161 ~l (2.0 mmol) pyridine and then 144 ~1 (2.0 mmol) of thionyl chloride. ~he Rolution is stirr~t at -10 or 15 ~inutes and then a solution of 228 mg (2.0 ~mol) potassium thiolacetate in 20 ml dimethylformamide is added. After s~irring 2 hours at -10, the tetrahydrofuran is removed in vacuo a~d the residue is poured i~to ethyl acetate. The solution is washed ~ith water and ~odium chloride, dried9 and evaporated. The residue is chro~atographed on 2~ g silica gel with an elua~t gradient of 0-25Z ethyl acetate in methylene chloride to g~ve the product, 44% yield.
EXAMP~E 10 (cis-3-Amino-2-bromomethyl-4-oxo-1-azetidinyl)thioacetoxyacetic acid (7) The product from Example 9 (195 mg, 0.3 ~mql) and 160 ~1 -- lg --~z~
.

1 (1.48 mmol) anisole are combined, cooled to 0, and then treated with 6 ml trlfluoroacetic acid~ The reaction is stirred and cooled 1 hour and the trifluoroacetrc acid is removed in vacuo.
Ether is added to the residue and the precipita~:ed trifluoroace~ate salt of the title compound is collected and drled under vacuum.

~hen the t-butoxycarbonylamino derivat:ive of E~ample 2 is substltuted for the isobornylo~ycarbonylamino derrvatives in Examples 4-9, the corresponding t-butoxycarbonylamino de~lvatives are obtained. Treating benzhydryl (cis-3-t-butoxycarbonylamino-2-bromomethyl-4-oxo-1-azetidi~yl)thioacetoxyacetate with trifluoro-acetic acld and anisole according to the procedure of Esample 10 also gives the trifluoroacetate salt of tcis-3-amino-2-bromometh 4-oxo-1-azetidinyl)thioacetoxyacetic acid.

[cis-3-(2'-Thienylacetamido) 2-bromo~ethyl-4-oxo-1-azetidiny~]-thloacetoxyace~lc acla- ~ -~
~ethylene chloride (5 ml) is added to 63 mg (0.154 mmol) of the salt of the 3-amino compound of Example 10 and the solution is cooled to 0 under argon. To the solutio~ is added 71 ~1 tO.51 mmol) trlethylamine followed by 23 ~1 (0.18 mmol) 2-thienyl-acet~l chlorite. The reactio~ is stirred 3 hours at 0, the methylene chloride ls removed in vacuo and the residue is dissolved i~ ethyl acetate and satura~ed ~a~C03. The aqueous phase ~s separated, washed ~ell with ethyl acetate and acidified to pH 2 ~ith dilute HCl. The acidic solution is estracted ~ith ethyl acetate. The trled estracts are evaporated to give the title compound.
EXA~PLE 13 ~cis-3-(296-Dimethoxybenzamido)-2-bromomethyl-4-oxo-l-azetidinyl]-thioacetoxyacetic acid Substltution of 2,6-dimethoxybenzoyl chloride for 2-t-nie~yl-, 'Z853~

1 acet~l chloride i~ the procedure of Example 12 gi~es the title product, 62% after preparative tlc on silica gel plates.
E}L~LE 14 A solutlon of 3.5 g (7.74 mmol~ of the tosylate from Example 6 in 10 ml dimethylformamide (D~F~ is added to a solution 3.32 8 (78.5 ~ol) LiCl in 30 ml DMF. The resulting solution is degassed for 15 mi~utes with argon and then heated for 3 hours a~
73 under argon. After cooling to room temperature, the mixture is taken up in saline solution and e~tracted with ethyl acetate.
The extracts are washed with saline solution, dried and evaporated to give cis-3-isobornyIoxycarbonylæ~ino-4-oxo-2-azetidinylmethyl chloride.
Similarly when the ~ocylate derivative i9 heated wlth a 10 mole excess o sodium iodide in acetone at 55-60 for 6-7 hours, 1; cis-3-isobornyloxycarbonylamino-4 oxo-2-azetidinylmethyl iodide is obtained.
~nen the abo~e chloro and iodo derivatives are carried through the reaction sequence of Examples 8, g and 10, the trifluoro-acetate salts of (cis-3-amino-2-chloromethyl-4-oxo-1-azetidinyl)thio-acetoxyacetic acid and ~cis-3-amino-2-iodomethyl-4-oxo-1-aze~idinyl) thioacetoxyacetic acid are obtained.
E~MPLE 15 Whe3 the amino compound prepared in Ex2mple 10 is acylated by standard methods know~ in the art ~ith the appropriate carboxylic ~5 acid or activated derivative thereof(all of which are k~own in the cepnalospori~ or penicillin arts) in which any sensitive group is appropriately protecte~ the followlng products are obtained after removal by standard methods of any protecting group:
[cis-3-phenylacetamido-2-Dromomethy1 4-oxo-1-azetidinyl]
rhioacetoxyatetic acid ~.~Z&S3(~

tcis-3~ hydroxyphenylaceta~ido)-2-bromomethyl-4-oxo~
azetidinyl~th~oacetoxyacetic acid tcis-3-(-aminoPhenylacetamido)-2-brGmomethyl-4-o:
azetidinyl]thioacetoxyacetic acid ~cis-3-(~-a~i~o-4-hydro~yphenylacetamido)~2-bromomethyl-4-; oxo-l-azetidinyl]thioaceto~yacetic acid fcis-3-(a-æmi~o-4-hydroxy-3-fluorophenylace amido)-2-bromomethyl-4-oxo-1-azetidlnyl]th:ioacetox7acetic acid cis-3~trifluorome~hylmercaptoaceta~ido 2-bromomethyl-4-; o~o-l-azetidinyl]thioacetoxyacetic acid, mp 65-95 (dec) [cis-3-methylmercaptoacetamido-2-bromomethyl 4-oxo-1-azetidinyl~thioaceto~yacetic acid [cis-3-methylsulfonylacetamido-2-bromomethyl-4-oxo-1-. azetldinyl]thioacetoxyacetic acid ~cis-3-t2',2',2'.-trifluoroethylsulfinylacetamido)-2-~5 - bromomethyl-4-oxo-1-azetidinyl]thioacetoxyacetic acid.
cis-3-cyanoacetamido-2-bromo~ethyl-4-oxo l-aze~idi~yl]-thioacetoxyacetic acid : [cis-3-cyanomethyl~ercaptoacetamido-2-bromomethyl-4-oxo-l-azetidinyl]thioacetoxyacetic acid tci~-3-(~-carboxY-3~-thienylacetamido)-2-bromom~thyl-4 oxo-l-azetidinyllthioacetoxyacetlc acid ~cis-3-t~-carboxyphenylacstamido)-2-bromomethyl-4-oxo-1-azetidinyl]thio~cetoxyacetic acid . -[cis-3-(3'-sydnoneacetamido)-2-bromom~ thyl-4-oxo-1-a2etidinyl]thioacetoxyacetic acid [cis~3~ tetrazolylacetaml~o)-2-bromomethyl-4-oxo-1-azetidinyl]thioacetoxyacetic acid [cis-~3-t4~pyridyl3~ercaptoacetamiao)-2-bromomethyl-4~oxo-l-azetidinyl]thioaceroxyacetic acid .

~2~3S3~
.

~cis-3-~sy~--methoxyimino-2'~furylacetamido)-2-bromo-methyl-4~oxo-1-azet$dlnyl]thloaceto~yacetic acida mp 7~-95~ (dec) ~cis-3-(2'-aminomethylphe~ylace~amido)-2-bromomethyl-4-oxo-l-azetidlnyl¦thioacetoxyacetic acid ~cis-3-(~-oxlminophenylacetamldo)-2-bromomethyl-4-oxo-1-: azetidinyl¦thioaceto~yacetic acid WheD (cis-3-~mino-2-chloromethyl-4-o~o-1-azetidinyl)-thioaceto~yacetic acid ls acylated by standard acyla~ion methods know~ i~ the art (ma~y of which are illustrated herein) with the appropriate carbo~ylic acid or an activated deri~ative thereof i~
~hich any sensitive group(s) are appropriately protectet, the follo~ing products are obtained after removal by standard methods o any protecting group(s):
lS ~cis-3-phenylacetamddo-2-chloromethyl-4-oxo-1-azetldlnyl]
thioacetoæyacetic acid ~:
~cis-3-(~-hydrozyphe~yiacetamido)-2-ch~orome~hyl-4-oxo-l-azetidinyl]thioaceto~yacetic acid ~ . ~
~ ~cis~3-(~-aminophenylacetamido)-2-chloro~ethyl-4-oxo-1-azetidi~yl]thioacetoxyacetic acid ~cis-3-(u-amino-4-hydroxyphenylacetamldo)-2-chloromethyl- : :
4-oxo-1-a~etidi~13thioacetoxyacetic acid ~cls-3-~-amlno-4-hydro~y~3-fluorophenylacetamido)-2-chloro~ethyl-4-oxo-1-azetid~nyl]thioacetoxyacetic acld ?5 [cis-3-trifluoro~ethylmercaptoacetaDldo-2-chloro~ethyl-4- -o~o-l-azet~dinyl]thloaceto~yacetic acid 3~ ' ~L~z~
.

, rcis-3-methylmercaptoaceeamido-2-chloromethyl-4 azetidlnyl]thioacetoxyacetic ac~d [cis-3-meehylsulfo~ylacetamido-2-chloromethyi-4-oxo~
azetidinyl]thioacetoxyace ic acid .rcls-3-(2~ ~2~ ~2~-triflusroethylsulfinylacetamido~-2-chloromethyl-4-oxo-1-azetidinyl]t~ioacetoxyacetic acid ~cis-3-cyanoacetamido-2-chlorome hyl-4-oxo-1-azetidinyl]
thioacetoxyac~tic acid ~cis-3-cyanomethylmercaptoaceta~ido-2-chloro~ethyl-4-oxo-l-azetidinyl]thioacetoxyacetic acid [cis-3-(~-carboxy-3'-thienylacetamldo)-2-chloromethyl-4-oxo-l-azetidinyl~thloacetoxyacetic acid [cis-3-(a-carbaxyphenylacetamido)-2~chloromethyl-4-oxo-l-azetidinyl]thioacetoxyacetic acid rcis-3-~3'-sydnoneacetamido)-2-chloromethyl-4-oxo-1-azetidinyl]thioacetoæyacetic acid tclq-3-(l'-tetrazolylace~m~to)-2-chloromethyl-4 azetldinyl]thioacetoxyacetic acid : . [cis-3-(4'-pyridylmercaptoacetamldo)-2-chloromethyl-4-oxo-l-azetidlnyl]thioacetoxyacetic acid.
E cis-3-(qy~-a-methoxyimino-2'-furylacetamido)-2-chloromethyl-4-oxo-1-szetldinyl]thioacetoxyacetic acid tcis-3-(2'-amdno~ethylphenylaceta~ido)-7-chloromethyl-4-o~o-l-azetidinyl]thioacetoxyacetic acid 2.~ rcl~-3-(~-oximinophenylaceta~ddo)-2-chloromethyl-4 l-azetidinyl]thioacetoxyacetic acid.
E2A~PLE 17 ~ -~hen (cis-3-acino-2-iodomethyl-4-oxo-1-azetidinyl)-thioace~
toxyacetic acid is acylated by standard acylation methods kno~ the 3~ art (many of which are.illustra~ed herein) ~ith the appropriate Z853~
carboxylic acid or an actlvated derivati~e ther~o~ 1~ which any seusitive ~roup(s) are appropr~ately p~otec~ed, the following products are obtained after removal by s~a~dard methods of a~y protecting gro~pts3:
[cis-3-phenylacetamido-2-iodomethyl-4- oxo-l-a etidi~y~]
~hioace~oxyace~ic acid ~ci3-3-(~-hydroxyphenylaceta~ido~~2-iodomethyl-4-oæo-l-szetidinyl~thioacetoxyacetic acid ; ~cis-3-t~-aminophenylacetamido)-2-iodo~ethyl-4-oxo-1 - ~o azetidinyl~thioace~oæyacetic acid [cis-3-(-æmino-4-hydroxyphenylacetamido~-2-iodomethy:l-4-oxo-l-azetidinyl]thioacetoxyacetic acid [cis-3-(~-amlno-4-hydroæy-3-fluorophenylaceta~ldo)-2-lodomethyl-4 oxo-l-azetidinyl]thioacetoxyacetic acid [cis-3-trifluoromethylmercaptoacetamido-2-iodome~hyl-4-. oxo-l-azetidinyl¦thioace~oxyace~ic ac~d - :
[cis-3-methylmercaptoacetamido-2-iodomethyl-4-oxo~
aze~id~nyl~thioacetoxyacetic acid [cis-3~methylsulfonylaceta~1do-2-iodomethyl-4-o~o-1-azetidinyl]ehioacetoxyacetic acid ~cis-3-(2',2',2'-trifluoroethylYulfinylace~a~ido~-2-iodo~ethyl-4-oxo-1-azetidinyl]thioacetoxyacetic acid ~cis-3-cyauoacetamido-2-lodomethyl-4-o~o-1-azetidinyl~
thioaceto~yacetic acid ~c s-3-cyano~ethylmercap~oace~amido-2-iodome~hyl-4-oxo-1-azet~dinyl~thinacetoxyacetic acid rcis-3-(a carbo3y-3'-thie~ylacetamido)-2-iodo~eth~l-4 oxo-l-azetidinyl]thioacetoxyacetic acid - ~cis-3-(~-carbo~phenylacetamido) 2-iodo~ethyl-4-oæo-1-azetidinyl]thioacetoæyacetic acid [cis-3-(3'-sydnoneaceeamido)-2-iodomethyl-4~oxo-1-azetidi~l]t~loaceto~yacetic acid . . .

1 tcis-3 (1'-tetrazolylacetamido)~2-iodomethyl-4-oxo~
azetidin~l]th~oacetoxyacetic acid ~ci~-3-~4'-pyrid71mercaptoace~amido)-2-iodomethyl-4-oxo-azetidi~yl~hioacetoxyacetic acid . ~cis-3-(sqn-a-m~tho~yi~ino-2'-furylacet2mido)-2-iodomethyl-4 oxo l-azetidi~yl]thioace~oxyacetic aeld Ecis-3-(2~-amiuomethylphe~ylacetamido)~2-iodomethyl-4-o~o-l-a~etidinyl]thioaceto~yacetic acid ~c~s-3-(a-oxi~i~ophen~lacetam~do)-2-iodomethyl-4-oxo-l-azetidinyl]thioacetoxyacetic acld EgAMPLE 18 cis-3-Amino-4-o~o-2-azetidinylme~hyl tosylate A solution of c -3-azido-4-oxo-2-azetidinylmethyl tosylate (5.0 ~) ln 50% aqueous acetic acid (50 ml) is cooled and then treated lS with zinc du~t (2.0 8)~ The reaction i8' ~tirred or 30.mlnutes, filtered,.and the solid washed with water (50 ml). The iltrate is satura~ed with ~2S over 1/2 hour, thY zi~e sulfide is re~oved by iltration and ~he filt~ate e~aporatet to near dryne.~s. The r~sidue i9 dis-~ol~ed in ethyl ace~ate-water and ad~usted to p~ 10. Phases are ~eparated and th~ aqueous layer is e~tracted with ethyl acetate.
The dried organic phases are evaporated to gi~e the ami~o compound;
3.0 g ~66Z).
EXAMP~E l9 2-Thie~ylacetic acid, the 3-aml~o tosylate fro~ Example 1~, and dicycloh~Yylcarbodi~mide ~3.7 m~ol o~ each) are stirred in meth~lene chloride for one hour at 0. The ~ixture is diluted with ethyl acetate (150 ml~ a~d filtered; the filtrate ~s washed with 5% ~a~C03, dilute ~Cl, and brine, dried, evaporated and crystallized fro~ acetone-ether to g~ve cis-3-(2~thienylacetamido~-4-oxo-2-azetid~yl~ethyl osylate;
O.g g (69%) ~p 121-124.
The 3-amino tosylate deri~ative i9 acylated with 0-for~yl-~andelic ~cld chloride in the presence of triethylamine at 0 ~n dry . .

~2i353~ i 1 methyle~e chloride to give cis-3-formyl~andelamido-4-oxo-2-azetidinylme~hyl tosylate, 98% mp 111 113~ ~dec).
The 3-a~lnoto~ylate der~vati~e i~ reacted ~i~h a~ equi~olar amou~t o phenoxyacetyl chlorlde in dry methyle~e ehloride and in the presence of triethylami~e to give cis-3-phe~oxyacetamldo-4-oxo-2-azetidi~ylmethyl ~osylate; mp 136 (dec).
E~AMPL~ 20 cis-3~ (t-8utylo~ycarbo~ylami~o)-a-phe~ylacetamido~-4-oxo-2-a7etidinyl~ethyl tosYlate 10To a solution of 2.7 g (0.01 mol) of the 3-amlno tosylate ~`
of Example 18 ~n 25 ml of dry methyle~e chloride i5 added 2.06 g (0.01 mol) of dlcyclohe~ylcarbodli~ide in 5 ml of methyle~e chlorlde.
The solution i9 stirred a~d cooled to 0 under argon and 2.47 ~ra~s (0.01 molas) o ~ -t-butyloxycarbonylphe~ylglyci~e i9 dig901ved 15in 50 ml dry methyle~e chloride and added tropwise o~er a period of 30 mi~utes. The d~cyclohexylurea i5 ~iltered off a~d washed with methylene chloride. The combiae~ f~ltrates are evaporated and th~
residue chro~a~ographed on 100 grams of Qilica gel. The product 2.1 8rams (42%), iQ eluted with 30% ethyl acetate ~n methyle~e chloride.
E~AMP~E 21 cis-3~ (t-Butylo~ycarbo~ylamino)--phenylacetamido]-4-oxo-2-azetidinylmethyl iodide A ~l~urz of 2 g (3.98 mmol) or product fro~ Example 20,

6 g (40 mmol3 of sodium ~odide and 150 ml of acetone ls thoroughly ~5 , degassed with ar~on and then heated at 55-6~ fvr se~en hour~. The m~ture is cooled ~o room temperature and ~he acetone is e~aporated.

The residue is partitioned between ethyl acetata and water. The organlc phase is separated and washed w~th aqueous sodium thiosulfa~e and saline. The dried solut~on is e~aporated to gi~e 1.48 g t81%) of the t~tle product.
.

- 27 - ~

3L3LZi~;3~

1 E~A~PLE 2 Benzhydryl [cis-3-(~-t-Butylo~ycarbonylaminv _ iodomethyl-4-oxo-L-azatidin~l~hydroxyacetate ~ suspension of 1.02 g ~2.21 ~mol) of product from Exampla 21 in 22 ml of dry ~etrahydrofuran is stirred undex argon ~ith cooling to -78 and 1.24 ml (2.44 mmol) of a 1.97M n-butyllithium in haxane solution is added. The mixture is stirred for 30 ~d~utes at -78 while 0.66 g (2.75 mmol) of be~zhydryl glyogylate in 20 ml of toluene is dried by distilling o~f 12 ml of the toluene. The remain~ng solution is addded to the reaction miæture. The resulting mixture is stirre~ at -78 for 1 hour and then i~ warmed in an ice bath ~o 0 for 10 minutes. The reaction ~s quenched by pouring into cold aqueous Na~2P04. The mixture is extracted with ethyl acetate and the ~ combined extracts are washed with saline. The dried snlutlo~ is e~aporated and the resldue is taken up in csrbon tetrachloride and then hexane is added to precipitate the product, 15 g (97%~.
~ E$A~PLE 23 Benzhydryl rcis-3-(-t-Butyloxycarbonylamino-~-phe~ylacetamido)-2-iodomethyl-4-oxoazetidinyl]thioacetoxYacetate To a cold solution (-10~) of 1.5 g (2.21 ~mol) of product from Example 22 u~der argon is added 17g ~1 (2.21 mmol) of pyridine followed by 157 ~1 ~2.21 ~mol) of thionyl chloride. The mixture is stirred for 15 ~nutes at -10 and then a solutlon of 252 m8 ~2.21 mmol) of potassium thiolacetate in 10 ml of dimethylformamide is added. After 15 ~inutes the solvents are removed in vacuo and the residue ls taken up in ethyl acetate and washed with ~ater and saline.
The dried ~olutio~ i9 evapcrated and the residue is chromatographed o~ silica ge~ wit~ 20X ethyl ace~ate i~ methyl~ne chloride as eluant ~
to give 0.43 g (25.5%) of product.

35~(~
1 ~YAXPLE 24 (cis-3-a-hminophe~ylacetamldo-2-iodomethyl-4-oxo-1-azetidinyl)-thioaceto~yacetic acid To a cold solution (0) of 397 mg ~0.524 mmol) of ester from Example 23 in 10 ml of methylene chloride is added 1 ml anisole and 9 ml trifluoroacetic acid. The mLLxture is stirred for 30 minutes a~ 0. The solvents are removed in vacuo and the residue is washed with ether and then with hexane. The residual solvent is pumped off to glve 230 mg (722) of title product as its trifluoro-O acetate salt.
EYAMPLE 25Treating the acylamino tosylate products prepared in Example 19 with ~aI ln acetone as set forth in Example 21 g~ves the following products:

cis-3-t2'-~hienylacetamido)-4-oxo-2-azetidinylmethyl iodide, 98% yield cis-3-formylmandelamido-4-oxo-2-aæetidinylmethyl iodide cis-3-phenoxyacetamido-4-oxo-2-azetidinylmethyl iodide.
The acylamino tosylate co~pounds prepared in Examples 19 and 20 are treated with Li~r as in Ex~mple 7 to give the following products:
cis-3-(2'-thienylacetamido)-4-oxo-2-aæetidinylme~hyl bromide cis-3-formylmandel2mido~4-oxo-2-azetidinylmethyl bromide _ -3-phenoxyacetamido-4-oxo-2-azetidinylmethyl bromide.
T~hen LiCl and the acylamino ~osylate compounds are reacted by the procedure i~ Example 14 the followi g products are obtained.
~5 Q -3-(2~-~hienylacetamido)-4-oxo-2-azetidinyl~nethyl chlor de cis-3-formylmandelamido-4-oxo-2-aæetld$nylmethyl chloride cis-3-pheno~yacetamido-4-oxo-2-azet~dinylmethyl chloride ~530 1 E~PLE 26 Benzyl [cis-3-(2'-Thienylacetamido)-2-iodomethyl-4-oxo-l-az2tidinyl]-hydroxyacetate To a suspension of 1.78 g (5.08 mmol) of cis-3-(2t-thienylaceta~ido)-4-oxo-2-azetidinylmethyl iodide and 2.66 g (16.2 mmol) of freshly distilled benzyl glyoxylate in 44 ml of anhydrous tetrahydrofuran under an argon atmosphere is added 1.31 ~1 (10.6 mmol) of freshly distilled boron trifluoride etherate. The reaction m~ture is stirred at ambient temperature for 1.25 hours, poured into aqueous ~aHC03 and e-xtracted ~7ith ethyl acetate. The combined extr2cts are washed copiously with ~ater and brine. The dried extracts are distilled in vacuo to give 4.5 g of clear orange gum which was rapidly chromatographed on a column of 90 g of sllica gel with methylene chloride and 20% ethyl acetate in ~ethylene chloride as eluants to give. the eitle product, 1.66 g (64"'?.
E~'~LE 27 Benzyl [cis-3-(2'-Thienylacetamido)-2-iodometh-~1-4-oxo-1-azetidinyl]-thioacetoxyacetate $he product of Example 26 is reacted with pyrid ne and thionyl chlorlde at -20 for 45 minutes and then with potassium thiolacetate, all according to the p~ocPdure given in Exa~ple 9, to give t~e title product. Rec~ystalli~ation from ethyl aceta~e~
hexane gave the product as a white crystalline solid, mp 159-62.
E~LE 28 ~cis-3-(2'-Thienylacetamido)-2-iodomethyl-4-oxoaz2tidinyl~trloacetox~J-~- acetic acid A solution of 1.05 g (7.6 mmol) of anhydrous potassium carbonate in 50 ml of ~ater is deoxygenated and~cooied to 0 under 2rgon. To this mixture is added a solutio~ or 0.796 g (1.39 ~mol~
of benzyl ester from ~a~ple 27 in 36 ~1 of ~etrahydro uran. ~ne 3~

~ 30 -8~i;3~11 1 raaction is deoxygenat2d agai~ and stirred at 0 for ca. 5 mln and then without cooling ror a total of 1 hour. The mixture is poured into 200 ml of e~chyl acetate and extracted with 5~ aq. ~aHC03, water and brine.
The aqueous ex,racts are co~bined, acidified to p~ 2 wi'h conc. H3P04, and then saturated with NaCl. The aqueous solutio~ is extracted with ~thyl acetate. The dried extracts are evaporated to ~ive 0.493 g (73~) of crude acid which is chromatographed on silica gel with an elua~t OI
70:23:5: ethyl aceiate:acetone:methanol:water. The acid is converted to its sodium salt by treating 0.525 g of the acid with 80 mg ~aHC03 in water and then lyophilizing the solutio~ to obtain the sodiu~ sal~.
E~b~LE 29 Methyl (cis-3-Phenoxyacetamido-2-iodomethyl-4-o:co-1-azetidinyl)-hydroxy~c2tate A solution of 0.360 g (l.0 ~mol) of cis-3-phcnoxy2cetzmido-4-o~o-2-azetidinylmethyl iodide, 0.440 g (5,0 ~mol) of ~ethyl glyo~vlate, and 246 yl (2.0 ~ol) of boron trifluoride etherate in 10 ml of annydrous tetrahydrofuran is stirred at ambient te~perature under an argon atmo-sphere for 5 hours. At this time 123 ~1 (1.0 m~ol) of boron trifluorids etherate i5 added and the ~ ture is stirred or an additio~al 2 hours.

The tetrahydrofuran is removed in vacuo znd the residue is taken up in ?0 ethyl acetate and eY.tracted with aqueous ~2HC03 and brine. The ethyl aceta~e solution is dried, Ciltered and evaporated to give 0.350 g of crude product which is purified by preparative thin-layer chrom2tography (silic2 gel GF); 0.174 g of pure product.

Methyl (cis-3-~henoxyacetamido-2-iodomethyl-4-oY.o-l-azetidi~7i)-thioacetoxvacetate -~ ethyl (c-s-3-phenoxyacetamido-2-iodomethyl-4-o~o-1-azetidi~yl)h}dro-~acetats (0.174 g, 0.39 mmol) is reacted wi~h 31.5 yl (0.39 m~ol) of anhydrous pyridine, Lollowed by 27.8 ~1 ~L2~5~

(0.39 mmol) of thionyl chloride as in Example 9. After 30 ~i~utes the solve~ts are removed in vacuo and a solution of 44.5 mg (0.39 mmol) of potassium thiolacetate in 4 ml of dimethylformamide is added a~ -10. After 30 minutes t,he dimethylformamide is removed in vacuo leaving 0.240 g of crude material which i~as purified by column chromatography on silica gel to give 0.092 g of the desired thioacetate. -(cis-3-Phenox~acetamido-2-iodomethyl-4-oxo-1-azetidinyl)thioacetoxy-acetic acid To a solution of 90 mg of methyl ester from ~xample 30 in 10 ml of 50% aqueous tetrahydrorurzn at 0 is added 1.0 ml of a solution prepared by dissolving 3.3 g of potassi~m carbonate and 2.0 g of 30dium bicarbonate in 40 ml o~ water (pH 9.2). This mixture is stirred at 0 for 30 minutes and at 25 for one hour and then the tetrahydrofuran is removed in vacuo. Solid sodiu~ chloride is added to the a~ueous residue. The solution is adjusted to pH 2 with H3P04 and extracted with ethyl acetate. The e~tracts are combined dried and evaporated to give 0.066 g of the, desired prod~ct.

EgAMPLE 32 cis-3~Azido-4-oxo-2-azetldinyl~ethyl bromide A ~ixture of 0.413 g (1.40 m~ol) of ci~-3-azido-4-oxo-2-azetidinyl~ethyl tosylate, 0.434 g (5.0 m~ol) of anhydrous lithiu~
bromide and 5 m- of anhydrous dimethylformamide is heated to 100 under argon for o~e hour. The solution is allowed to cool to 25, poured into ethyl acetate and extracted copiously with water. The ethyl aceta~e layer is dried and evaporated to give 0.270 g (~$%) of the title product.

, 53~
.
1 E ~YPLE 33 Ben~hydryl (c_s-3-Azido-4-oxo-2-bro~omethyl-1-azetidinyl)hydro~J-acetate A solution of 4.17 g (174 mmol) benzhydryl glyo~ylate in 80 ml toluene is heated to reflux un~er an argon atmosphere ar.d 12 ml of toluene-water mixture is removed by distillation. The remaining solutio~ is cooled to ca. 50 and 2.02 g (9.85 ~mol) of cis-3-azido-4-oxo-2-azetidinemethyl bromide is added. The mixture is heated at 90 for 5 hr and then allowed to cool to 25. The toluene is removed in vacuo to afford 6.05 g OLC orange gum which is chromatographed on 182 D of silica gel and with 20Z ethyl acetate in cyclohexane to give 3.22 g (73%) of product as a mixture of diastereo-isomers; tlc: 20,'o eth~l acetate in cyclohexane; silica gel GF; R' = 0.37 and 0.29. The lower Rf diastereoisomer was obtained as 2 crystalline solid, mp 114-116 (ether).

Ben~hydryl (cis-3-Azido-4-oxo-2-bromomethyl-l~azetidirly)thioaceto~yacetate To a cold solution (-20) of 0.840 g (1.89 ~mol) of-product from Example 33 lr. 22 ml of anhydrous tetrahydrofuran under argon is added 1~3 ~1 (2.39 mmol) of anhydrous pyridine followed by 172 ~1 (2.39 mmol) of thionyl chloride. The reaction mixture is stirred at -20 for one hour ard then a solution of 0.315 g (2.76 m~ol) ~f potassium thiolacetate in 22 ml of anhydrous dimethylfor~amide is added. The ~eaction is stirred at -20 for 3~ minutes and ther. allowed to stand at -23 overnight. The solution is poured into e~hyl acetate ~~ and extracted copiously with water and th~n once ~ith 0.1 N boric ac~a, NaHC03 solution and brine. The etnyl acetate layer is dried and evaporated to g-ve 1.0 g of clear, light-yello~ gum. This gum ia crystallized f,o~ etner-he~ane fi st at 25 and then at -23~ overr.igh.
to gi~e 0.807 g (8570) of the title thioacetate, mp 114-115.5. Nuclea.

magnetic resonance analJsis ir.dicated that this ~aterial was 2.6:1 3~

mixture of diastereoiso2ers.
u~PLE 35 Benzhydryl [cis-3-(2'-Thienylacetamido)-2-bromomethyl-4-oxo-1-azetidinyl~thioacetogyacetate A solution of 0. 044 g (0.088 m~ol) of benzhydryl ester from Example 34, 0.084 g of platinum oxide, 0.318 g of p-toluenesulfonic acid monohydrate, 3.5 ml of e~hyl acetate, and 3.'i ml of ethanol is hydrogenated at ambient temperature and atmospheric pressure for one hour. The mixture is filtered and the solvents are removed in vacuo.
The residue is dissolved in 6 ml of anhydrous methylene chloride and cooled to 0 under argon. To this solution is added Z4.5 ~1 of triethylamir.e follo~ed by 11 ~1 of thienylacetyl chloride. The reaction mixture is stirred at 0 for one hour and allowed to stand at -23 overnight. The product i9 isolated b~ ethyl acetate e~traction to afford 0.058 g title product.
Treatment of the above product with trifluoroacetic acid by the procedu_e of Example 24 gives the same product as in Example 12.
E~AMPLE 36 Benzyl [cis-3-(2'-Thienylacetamido)-2-(~-tosylo~3ethyl)-4-oxo-l-.
azetldinyl~hydro~acetate Whe~ 1.6 g (4.06 mmol) of cis-3-(2'thienylacetamido)-4-oxo~2-azetidinylmethyl tosylate, 1.3 g (7.93 ~mol) oE ben~-Jl glyo~y-late (freshly distilled), and 0.85 ml (6.9 m~ol) boron trifluoride etherate are reacted together for 3 hour~ in 75 ml tetrahydrofu.an (freshly distilled) according to the procedure of Example 29, the ~S title product is obtained. The product is chromatographed ~n silica gel with 3:1 chloroform: ethyl acetate as eluant.

~L~Z~53~

1 E~MPLE 37 _ _ rcls-3-(2'-Thienylacetamido)-2~ tosyloxymethyl)-4-oxo-l-azetidinyl~
thioacetoxyacetic zcid When 1.23 g (2.2 mmol) of the produc~ from ;xample 3O, 0,18 ml (2.23 mmol) pyridine, 0.16 ml (2.22 mmol) thionyl chloride, and 454 mg (3.98 mmol) potassium thiolacet~te are reacted according to the procedure of Example 9 benzyl [cis-3-(2'-thienJlacetamido)-2-(p-tosyloxymethyl)-4-oxo-l-azetidinyl]thioacetoxyacetate is obtained;
1.56 g crude yield, 0.52 g after chromatography on silica gel with 10% ethyl acetate in cnloroform as eluant.

The benæyl ester (0.52 g) in 20 ml tetrahydrofuran and 14 ml water is hydrolyzed by the procedure of Example 31 using 6 ml of the base solution to give the title product; 0.11 g. The product is chromatographed on silica gel (1:1 ethyl acetate:chloroform w~th 0.5% for~ic acid). The product is dissolved in dioxane, treated with an equival2nt of aqueous NaHC03 and lyopholized to give thè
sodium salt.
E~ PLE 38 [cis-3-~2'-Thienylacetamido)-2-chloromethyl-4-oxo-l-azetidinyl]-thioacetoxyace~ic acid .
cis-3-(2'-Thienylacetamido)-4-oxo-2-azetidinylmethyl chloride (1.35 g) ls condensed with benzhydryl glyoxalate according to the procedure of Example 22 to give 1.7~ g (75~O) of the conden-sation product after chromatography on silica gel with 20h~ ethyl aceeate in chlorofor~ as eluan~.

~~ The abo~7e product (1.60 g) is converted to benzh-~dryl ~ [cis-3-(2'-thienylacetamido-2-chloromethyl-4-oxo-i-azetidinyl]
; thioacetoxyacetate accordi~g to the procedure of ~-xample 9; 1.31 g (69%).
The benæhydryl ester (1.24 g) is.cleaved accordir.g to the pro~edure of Example 24. The crude product is chromatographed on ~lZ~53(1 . silica gel (1:1 ethyl acetate:chloroform ~ith lZ formic acid) to glve 0.78 g (89Z) of title product, which is converted to its sodium salt by the procedure in Example 37.
E~AMPLE 39 ~cis-3-(2'-Thienylacetamido)-2-iodomethyl-4-oxo-1-2zetidinyl]-thiobenzoyloxyacetic acid Benz'nydryl cis-3-(2-thienylacetamido~-2-iodo~ethyl-4-o~o-l-azetidinyl)hydroxyacetate (92 mg) is treated in 5 ml methylene chloride with 11.3 yl thionyl chloride and 12.5 ~1 pyridine as in E~ample 9 and then ~ith one-half of a solution of 42;7 mg thiolbenzoic acid and 15 mg NaH in 4 ml dimethylforma~ide. The product i9 .chromatographed on sllica gel wieh chloroform as eluant; 103 ~g.
The benzhydryl ester (100 mg) in 3 ml methylene chloride is treated with 1 ml tri1uoroacetlc acid ~or one hour at -10 to 0. After an acid-base extraction sequence 34 mg of title product is o.btained and chromatographed on silica gel with 2~ acetic acid in ethyl acetate eluant.

(cis-3-~andelamido-2 iodomeehyl-4-oxo-1-azetidinyl)th~oacetoxy-acetic acid cis-3-(D)-0-Formylmandelamido-4-oxo-2-aze~idinylmethyl iodide (0.388 g, 1.0 ~mol) is condensed ~lth benzhydryl glyo-~ylate by the procedure of ~Yample 22. The condeusat~on product is isola~ed as in E~ample 22 and t~en reacted a~ -20 ~ith 72 ~1 (1.0 mmol) thionyl chloride ana &1 ~1 (1.0 ~ol) pyridine for 30 minutes as in Example 23. The solvents are distilled off at 1 mm pressure and the residue is dissolved in 25 ml dry d~methyl0rm2mide and cooled ~o -25~. A solut~on of ~.121 g (1~06 ~ol) of po~assiu~
~hiolacetate in 2 ml dimethylformamide is added and the react.on is allowed to stand at -23 for 48 hours. The produc~ is isolated ~L~ZI~S3~

as in ~xample 23 and chromatographed on silica gel using ethyl acetatebenzene as eluant to give 0.183 g of benzhydryl (CiS~
mandelamido-2-iodomethyl-4-oxo-azetidinyl)thioacetoxyacetate, [~]25_ 18.1 (c l, CH30H), and 0.216 g of benzhydryl (cis-3- -0-formylmandelamido-2-iodomethyl-4-oxo-1-azetidinyl)thioacetoxyacetate.
The benzhydryl desformyl product is dissolved in dry methy-lene chloride and stirred with trifluoroacetic acid and anisole at 0 for 20 minutes. The solvents are removed in vacuo and the residue '~
is triturated with hexane and then ether. The product is dissolved in ethyl acetate and precipitated by adding hexane; [~]D5- 24.0 (c 1, CH30H~.

~cis-3-(a-Carboxyphenylacetamido)-2-bromomethyl-4-oxo-1-azetidinylJ-thioacetoxyacetic acid A solution of the trifluoroacetate salt product of Example 10 (0.89, g, 2.1 mmol) in methylene chloride (80 ml) is flushed with argon, cooled to 0 and treated with diisopropylethylamine (0.82 g,~6.35 mmol) which is dissolved in methylene chloride. Phenylmalonic acid chloride mono-t-butyl ester (1.616 g, 6.35 mmol) (prepared by treating the acid with an equivalent of oxalyl chloride and pyridine at 45~ fo,r 90 minutes) in methylene chloride (20 ml) is added dropwise and stirred for 30 minutes. The reaction is stored at -25 overnight and then the solvents are removed. The residue is partitioned between ethyl acetate and saturated NaHC03. The aqueous layer is acidified to pH 2 and extracted with ethyl acetate. The dried extracts are . ' ~ . ' , evaporated to give the t-bu~yl ester which was treated at 0 for 30 minutes with trifluoroacetic acid (12 ml) in methylene chloride (12 ml) and anisole (2.3 ml~. The'solvents are removed and the residue is chromatographed on silica gel (50 g) with 50:50:4 chloroform:ethyl acetate.formic acid as eluant to give the title product~ 174 m~.

.

~285~

(cis-3-Phenylacetamido-2-bromomethyl-4-oxo-1-azetidinyl)thioacetoxy-acetic acid Th~ trifluoroacetic acid salt of ~xample 10 (288 mg, 0.677 mmol), phenylacetic acid chloride (122 ~1, 0.925 ~mol) and triethylamine (314 ~1, 2.24 mmol) are reacted in methylene chloride (,32 ml) as described in Example 41 to give the title product after chromatography on silica gel (10 g) with 50:50:3 chloroform:ethyl acetate:formic acid as eluant, 146 mg.

[CiS-3- (~-Aminophenylacetamldo~-2-bromomethyl-4-oxo-1-azetidinyl]-thioacetoxyacetic acid A solutlon of N-t-butoxycarbonylphenylglycine (575 mg, 2 . 29 mmol) in dry tetrahydrofuran (9.5 ml) is cooled to -20~ and then treated with triethylamine (321 ~1) and isobutyl chlorofonnate .(,297 mg, 2.29 mmol) for one hour at -20. To the reaction is added dropwise a cold solution of the trifluoroacetic acid salt of Example 10 (,974 mg, 2.29 mmol) and triethylamine ~739 ~1) in 50% aqueous tetrahydrofuran. The reaction is stirred at -10 to'-20 for one hour and at 250 for 2.5 hours. The solvents are removed and the residue is treated with p~ 7 buffer and ex~racted with ethyl acetate.
The aqueous layer is acidified to pH 2.5 and,extracted with ethyl acetate. Both sets of extracts yield the t-butoxycarbonyl derivative of the title compound which is purified by chromatography on silica gel with chloroform:ethyl acetate:formic acid (50:50:3) as eluant, 410 mg;
The t-butoxycarbonyl derivative ~80 mg) in methylene chloride (,2.9 ml) and anisole (0.29 ml) is cooled to 0 under argon and treated with trifluoroacetic acid (2.6 ml) for 30 minutes. The solvents are removed and the solid is triturated with ether to give the title com-3~ - 38 -~ILZ~3,53~

1 pound as its ~rifluoroacetic acid salt, 62.5 mg ~]D5 = -19.26 (1%
in metha~ol).

E~AMPLE 44 [CiS-3- (2'-Aminomethylphenylacetamido)-2-bromomethyl-4-oxo-1-~ acetidinyl]thioacetoxyacetic acid .
A solution of 2-t-butoxycarbonylaminomethylphenylacetic acid (1.32 g, 5 mmol) in dry tetrahydrofuran (30 ml), triethylamine ~0.7 ml), and N-methylmorpholine (3 drops) is cooled to 10 and then a solution of i-butyl chloroformate (0.68 g, 5 mmol) in tetra-0 hydrofuran (7 ml) is added. After stIrring for 15 minutes a solution of the product of Example 10 as its HCl salt (1.73 g, 5 mmol) in triethylamine (0.7 ml) and 50~ aqueous tetrahydrofuran (30 ml) is added. The reaction is stirred overnight at 25, filtered an~
evaporated to dryness. The residue is partitioned between ethyl acetate and water and the dried organic phase is evaporated. The oil (2;3 g) was chromatographed on silica gel (~0 g) with 9:1 ethyl acetate:ether as eluant to give the N-protected derivative.
To a suspension of the above product (1.0 g) in benzene (25 ml) and m-dimethoxybenzene (5 ml) is added trifluoroacetic acid (5 ml) and m-dimethoxybenzene (5 ml). The reaction is stirred over-night at 25, diluted with ether (250 ml) and filtered to collect the solid product. Chromatography on silica gel with 85:15 acetone:
water as eluant gives the title compound.

~5 The alkali metal salts of the compounds of this invention are prepared by treating the compound with an aqueous solution con-taining an equivalent of ~aHC03 and lypholizing the solution to ob-~aln salt.
An alternate procedure involves treating a methanol solu-tion of the acid compound with an equivalent of a solution of sodium j ~L~28~3C~

1 2-ethylhexanoate in isopropanol. Ether is added to precipitate the salt.

-An injectable pharmaceutical composition is prepared by dissolving 200 mg of sodium ~cis-3-~2'-thienylacetamido)-2-bromo-methyl-4-oxo-1-azetidiny~ thioacetoxyacetate in sterile water or sterile normal saline. Pharmaceutical compositions of other~com-pounds which have antibacterial activity within this invention for example, the compounds of Examples 41, 42, 43 and 44, are prepared as above.

~0 ~S

Claims (5)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1 . A process for preparing a compound of the formula wherein A is amino or protected amino;
X is CH2-halogen, or CH20S02R;
R is lower alkyl;
Q is hydrogen, lower alkyl, or halo;
Y is S?-E or hydroxy;
E is hydrogen, lower alkyl, trifluoromethyl or phenyl unsubstituted.or substituted with one or two sub-stituents selected from the group consisting of lower alkoxy, lower alkyl, halo, and nitro; and M is hydrogen or a carboxylic acid protective ester group, comprising (a) condensing a compound of the formula where A is protected amino and X is as defined above, with a compound of the formula OHC-COOM where M is a carboxylic acid protective ester group;

(b) when Y is SCOE, treating the condensation product with a halogenation reagent and an alkali metal salt of a thiolacid of the formula HSCOE where E is as defined above;
and (c) when A is amino and M is hydrogen, removing the protective groups.

2. A process as claimed in claim 1 where A is amino, t-butoxycarbonylamino, trichloroethoxycarbonylamino, benzyloxycarbonyl-amino, p-methoxybenzyloxycarbonylamino, p-nitrobenzyloxycarbonylamino, or isobornyloxycarbonylamino; X is CH2-halogen; E is methyl or phenyl and M is hydrogen, 2,2,2-trichloroethyl, benzyl, benzhydryl, t-butyl or methyl.

3. A process as claimed in claim 2 where X is CH2Br, Y is SCOE, and E is methyl.

4. A process as claimed in claim 3 for preparing benzyl, benzhydryl or t-butyl (cis-3-t-butoxycarbonylamino-2-bromomethyl-4 oxo-1-azetidinyl)thioacetoxyacetate comprising (a) condensing with benzyl, benzhydryl or t-butyl glyoxylate and (b) treating the condensation product with thionyl chloride and an alkali metal salt of thiolacetic acid.

5. A process as claimed in claim 3 for preparing (cis-3-amino-2-bromomethyl-4-oxo-1-azetidinyl)thioacetoxyacetic acid com-prising (a) condensing with benzyl, benzhydryl or t-butyl glyoxylate (b) treating the condensation product with thionyl chlorlde and an alkali metal salt of thiolacetic acid (c) removing thP amino and carboxylic acid protective groups.