CA1075679A - 3-heterothio-7-thioureido cephalosporins - Google Patents

Abstract

Abstract Compounds of the formula wherein R is hydrogen or methoxy; R1 is hydrogen, lower alkyl, cyclo-lower alkyl, cyclo-lower alkenyl, cyclo-lower alkadienyl, thienyl, furyl, phenyl, phenyl-lower alkyl, or substituted phenyl wherein said phenyl substituent is halo-gen, hydroxy, amino, lower alkyl or lower alkoxy; R2 is hydrogen, lower alkyl, lower alkenyl, cyclo-lower alkyl or lower alkanoyl; R3 is hydrogen, lower alkyl, phenyl-lower alkyl, diphenyl-lower alkyl, tri(lower alkyl)silyl, a salt forming ion, or

Description

~ 79 GG231 This invention relates to new cephalospor.ins of the formula O R
Rl-CH-C-NH I ~ S ~

C--S 0/ - ~CH 2 - S- R4 l-R2 COOR3 H
wherein R is hydrogen ox methoxy; Rl is hydrogen, lower alkyl, cyclo-lower alkyl, cyclo-lower alkenyl, cyclo-lower alkadienyl, thienyl, furyl, phenyl, phenyl-lower alkyl, or substituted phenyl wherein said phenyl substituent is halo-gen, hydroxy, amino, lower alkyl or lower alkoxy; R2 is hydrogen, lower alkyl, lower alkenyl, cyclo-lower alkyl or lower alkanoyl; R3 is hydrogen, lower alkyl, phenyl-lower alkyl, diphenyl-lower alkyl, tri(lower alkyl)silyl, a salt forming ion, or -CH-O-~-Rs; R5 i.s lower alkyl, phenyl or phPnyl lower alkyl; R6 is hydrogen or lower alkyl and R4 is a 5- or 6-membered heterocyclic ring containing carbon and 1 to 4 atoms selected from the group consisting o nitrogen, sulur and oxygen, unsubstituted or substituted with one lower alkyl, lower alkoxy, halogen or exocyclic oxygen.
The various groups represen~ed by the symbols have the mea~ing defined below and these defini~ions are retained throughout this specification.
The lower alkyl groups referred to throughout this specification include straight or branched chain hydrocarbon group~ containing 1 to 7 carbon a~oms, preferably 1 to 4 carbons and especially methyl and el:hyl~ Examples oE the type of groups contemplated axe methyl, ethyl, propyl, isopropyl~ butyl, isobutyl, t-butyl, etc. The lower alkoxy :

~5167~33 groups referred to below include such lower alkyl groups attached to an oxygen, e.g., methoxy, ethoxy, propoxy, etc. The 1 to 4 and especially 1 and 2 carbon members are also preferred in this instance. The phenyl-lower alkyl and diphenyl-lower alkyl groups include such lower alkyl groups attached to a phenyl, e.g., benzyl, phenethyl, diphenylmethyl, etc., the three mentioned are preEerred.
The lower alkenyl groups are mono-unsaturated radicals like the lower alkyl groups referred to above and the groups having up to 4 carbons are similarly preferred.
Cyclo-lower alkyl refers to the saturated alicyclic groups having 4 to 6 carborls in the ring, i.e., cyclobutyl, cyclopentyl and cyclohexyl. The terms cyclo-lower alkenyl and cyclo-lower alkadienyl refer to rings having 4 to 6 carbons with one or two double bonds, respectively, i.e., cyclobutenyl, cyclopentenyl, cyclohexenyl~ cyclopentadienyl, cyclohexadienyl, etc. The double bond or bonds may be located at various positions. The 5- or 6-carbon rings are preferred, especially cyclopentyl, cyclohexyl, cyclohexenyl and 1,4-cyclo-hexadienyl.
The lower alkanoyl groups include the acyl radicals of the lower (up to 7 carbons) fatty acids, e.g., acetyl, propionyl, isopropionyll butyryl, ekc., preferably those having up to 4 carbons and especially 2 or 3 carbons.
The substituted phenyl groups are thos~ having one to three (preferably only on~ but the same when more than one is present) of the ~imple substituents halogen (prefer-ably chlorine or bromine), hydroxy, amino, lower alkyl or lower alkoxy, e.g., 2-, 3- or 4-chlorophenyl, 2-, 3- or 4 bromophenyl, 3,4-dichlorophenyl, 2-methylphenyl, 4-ethoxy-phenyl, etc. The Cl to C~, and e.specially Cl and C2, lower .. .
alkyl and lower alkoxy groups are preferre(l.

75~

The salt forming ions represented by R3 are metal ions, e.g., aluminum, alkali metal ions such as sodium or potassium, alkaline earth metal ions such as calcium or magnesium, or an amine salt ion, of which a number are known for this purpose, for example, phenyl-lower alkylamines such as dibenzylamine or lower alkylamines such as methylamine, triethylamine, etc.
The heterocyclic groups represented by R4 and des-cribed above are particularly r; - 1~ 9 ~R~ ~ o R7 N - N N - N ~ r ~ Ra R7 O `O

wherein R7 is hydrogen or lower alkyl preferably havi~g up to 4 carbons and especially 1 or 2 carbons, and R8 is hydro-gen, halogen, lower alkyl or lower alkoxy/ the latter twohaving preferably up to 4 carbons and especially 1 or 2 car-bons.
Preferred embodiments of this invention are as follows:
R is hydrogen or methyl, especially hydrogen.

R1 is phenyl, benzyl, substi.tuted phenyl wherein the phenyl substituent is C1, Br, hydroxy or amino, C5~C6 cyc]o-lower alkyl, Cs-C6-cyclo-lower alkenyl, Cs-C6-cyclo-lower alka-dienyl or thienyl.
; R2 is hydrogen or lower alkyl of 1 to 4 carbons.
' -3_ ~75~79 GG231 R3 is hydrogen, lower alkyl of 1 to 4 carbons, benzyl, phenethyl, diphenylmethyl, trimethylsilyl, alkali metal or -CH2-O-C-R5.
R5 is lower alkyl of 1 to 4 carbons, phenyl, benzyl, or phenethyl.
The most preferred embo~iments areO
R is hydrogen.
Rl is hydrogen, phenyl~ cyclohexadien-l-yl or thienyl, especially phenyl or thienyl.
R2 is hydrogen or me~h~l, especially hydrogen.
R3 is hydrogen, diphenylmethyl, sodium or potassium, especially hydrogen.
R4 is h N N N N- I-I CH3 ~ 5 ~D~C~ ~ S

e~pe~ially 5-methyl-1,3,4-thiadiazol-2-yl and l-methyl-lH-tetrazol-5-yl~
The preferred general method for the synthesis of compound~ of formula I comprises -treating a compound of the foxmula R

Rl-fH-CO-NH - I S ~ ... .
II NH2 ~ _ N ~ CH2-S-R~

with an isothiocyanate having the formula III R2-N=C-S

The symbols have the meaning defined above.

_4_ According to this method the starting material is dissolved or suspended in an organic solvent .inert to the reaction like methylene chloride, which is preferred, metha-nol, ethanol, acetonitrile, dimethylformamide, etc~ An organic amine base like trie~hylamine may be present to aid in solvationO Ambient temperature (up to ~bout 25) or be-low (to about 0) may be used.
As an alternative, a compound of the formula Rl-CH-COOH

ll l S H

can be used as starting material. This is made -to react with a 3-heterothio-7-amino substituted cephalosporin of the formula 112N ~ ~ cl~2-S--R4 wherein R3 is preferably diphenylmethyl or t-butyl or other ester protecting groups.
This reaction is carried out preferably by convert-ing the compound of formula IV to a mixed carbonic or other - anhydride by treating a solution of that compound in an organic solvent containing a tri~lower alkyl)amine with an ; anhydride forming agent, i.e., a lower alkyl chloroformate, an aryl chloroformate, or an acyl halide, at reduced tempera-tures of from about 0C to about -2()~C.
The compound of formula II can also be converted to an activated eqter by reacting with a carboxyl group activat-,~ .

. .

1~75679 GG231 ing agent such as dicyclohexylcarbodiimicle or bisimidazole carbonyl. In some cases the carboxyl group may be activated by conversion to an acid halide, e~g., the chloride or to an azide.
According to still another alternative, a compound of the formula 8 -- s Rl -CH-c-NH ~ 8 VI C=S ~ ~ N ~ CH2-O-C-~H3 N--R2 ' is made to react with a compound of the formula in a solution at a pH of from about 7.8 to about 8Ø
The starting material of formulas IV and VI are pro- .
duced by the methods described in U.S, Patent No. 3,741,962, i.ssued June 26, 1973.
The starting materials of formula V are produced by reacting 7-aminocephalosporanic acid or 7-amino-7-methoxy- :
cephalosporanic acid with the compound of formula VII as ; descxibed above, The various starting materials and intermediates can also be produced by the methods described in U.S. Patent Nos.
; 3,641,021, 3,759,904, 3,796,80]., 3,813,388, 3,840,531 and 3,867,380; British Patent NosO 1,3487984 and 1,348,987 (March ; 27, 1974); and Belgi.an Patent No. 7~,8,528 tDecember 15, 1971~.
The methods di~close~l therein a~e a~ lica~ to other mclllbcrs of the same serie~.

.

107 567~ GG231 The compounds of formula I wherein R3 is lower alkyl, phenyl-lower alkyl, diphenyl-lower alkyl, or the acyloxy-methyl group - ~ -O-~-R5 are obtained by reacting the 3-heterothio-7-amino substituted cephalosporin of formula V
or the 7-ACA either before or after the acylation of the 7-amino substituent with one or two moles of a compound of the formula VIII halo-R3 or IX R N-~ N-wherein halo is preferably chlorine or bromine in an inert solvent such as dimethylformamide, acetone, dioxane, benzene, or the like at about ambient temperature or below.
Similarly, the compounds of formula I wherein R3 is tri(lower alkyl)silyl are obtained by introducing such groups onto the 3-heterothio cephalosporanic acid moiety either be-foxe or after the acylation reaction.
The carboxylate salts of the compound of formula I
are formed by reacting the carboxyl gxoup of the cephalospor-anic acid moiety, i.e., R3 is hydrogen, with any of the salt forming ions described above.
lt will be appreciated that certain of the compounds of formula I can be optically active due to the presence of an asymmetric carbon atom. By selection of the appropriate starting material, such compounds can be obtained as a mixture of optically active isomers or can be isolated as a single isomer. ~he various isomers as well as their mixtures are within the scope of this invention. Where possible, it is preferred to obtain the D-isvmer since that is the one which generally exhibits greater biological activity.
The compounds of formula I have a broad spectrum of antlbacterial activity agai~st both gram positive and gram ~75679 GG231 negative organisms such as Staphylococcus aureus, Salmonella schottmuelleri, Pseudomonas aeruginosa, Proteus vulgaris, _ Escherichia coll and Streptococcus pyogenes They may be used as antibacterial agents in a prophylactic manner or to combat infections due to organisms such as those named above, and in general may be utilized in a manner similar to cephra-dine and other cephalosporinsO For example, a compound of formula I or a physiologically acceptable salt thereof is used in various warm-blooded animal species in an amount of about 1 to 100 mg/kg, daily, orally or parenterally, in single or two to four divided doses to treat infections of such bac-terial origin.
Up to about 600 mg of a compound of formula I or a physiologically acceptable salt thereof is administered by incorporation in an oral dosaye form such as tablet, capsule or elixir or in an injectable form in a sterile aqueous vehicle prepared according to conventional pharmaceutical practice.
They are also useful as nutritional supplements in animal feeds.
The following examples are illustrative of the inven-tion and serve as models for the preparation of other members.A11 temperatures are in degrees celsius~
Example 1 3-[[(5-methyl-1,3,4-thiadiazol-2-yl)thio]methyl3-7-amino-8-oxo-5-thia-1-azabicyclo~4~2.0]oct-2 ene-2 carboxylic acid A mixture of 13.6 g (0.05 M) of 7-aminocephalosporanic acid l7-ACA) in 100 ml of water and 50 ml of acetone are brought to pH 8 with sodium hydroxicle while stirring. 7.5 g ' ~ ~ -8-.. . .

~.~75679 (0.057 M) of 2-methyl-1,3,4-thiadiazole-5-thiol are added and the mixture is heated at 80 for four hours. After cooling to 5 , this is acidified to pH 3.5 with dilute hydrochloric acid and stirred for 15 minutes. The precipitated solld is filtered under suction and washed with acetone~ This 3-[[(5-methyl-1,3,4-thiadiazol-2-yl)thio]methyl]-7-amino-8-oxo-5-thia-1-azabicyclo- -[4.2.0]oct-2-ene-2-carboxyllc acid is purified by dissolving in sodium bicarbonate solution and reprecipitating with 2N
hydrochloric acid; yield 12.7 g., m.p. 206 .
Example 2 3-[[(3-Methyl-1,2,4-thiadiazol-5-yl)thio]methyl]-7-amino-8-oxo 5-thia-1-azabicyclo[4 2.0]oct-2-~ne-2-carboxylic acid By substituting 3-methyl-1,2,4--thiadiazole-5-thiol for the 2-methyl-1,3,4-thiadiazole-5-thiol in the procedure ; of Example 1, 11.6 g. of 3-[~(3-methyl-1,2,4-thiadiazol-5-yl)-thiolmethyl3-7-amino-8-oxo-5-thia-1-azabicyclo[4.2.~]oct-2-ene-

2-carboxylic acid, m.p. 186 (dec.) are obtained.
Example 3 :

3-[[(1-Methyl-lH-tetrazol-5-yl)thiolrnethyl]-7-amino-8-oxo-5-~thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid By substituting 0.057 M of l-methyl-lH-tetrazole-5-thiol for the 2-methyl-1,3,4--thiadiazol 5-thiol in the procedure of Example 1, 3-[[(1-methyl-lH-tetrazol-S-yl)thio]methyl]-7-amino-8-oxo-5-thia-1-azabicyclo E4 . 2.0]oct-2-ene-2-carboxylic r acid is obtained.
.

:
;

~, ': : , --g _ .. . . ..

~7567~39 Example 4 7-Amino-3-[~(5-methyl-1,3,4-thi diazol-2-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclol4.2.0~oct-2-ene-2-carboxylic acid, __ _ diphenylmethyl ester .
18 g. of 7-amino-3-[[~S-methyl-1,3,4-thiadiazol-5-yl)thio]-methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid are suspended in 350 ml. of tetrahydrofuran. 4.1 ml. of 70% perchloric acid are added dropwise. After 30 minutes, a slightly turbid solution forms. This solution is -filtered and to the filtrate is added dropwise with stirring 12 g. of diphenyldiazomethane and 20 ml. of tetrahydrofuran. After 3 hours, the reaction mixture is poured into 2 liters of absolute ether. The solid, light brown precipitate, which is the perchloric acid salt of the desired productl is dried over Kieselgel in a desiccator. To obtain the base, the perchloric acid salt is dissolved in water and treated with the calculated equivalent of potassium bicarbonate. The aqueous solution ~ obtained is extracted with chloroform. The chloroform phase ; is treated with activated carbon and sodium sulfate to obtain 10 g. of the product, 7-amino-2-[[(5 methyl-1,3,4-thiadia-zol-2-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo14.2.0]oct-2-ene-2-carboxylic acid, diphenylmethyl ester, as a light brown powder, m.p. 157-159. The product is recrystallized ~rom tetrahydrofuran/petroleum ether.
7-Amino-3-r[(3-methyl-1,2,4-thiadiazol-5-yl)thiolmethyl]-7-amino-8-oxo-5-thia-1-azabicyclo[4.2.û]oct-2-ene-2-carboxylic acid, diphenylmethyl ester is similarly obtained by substituting the product of r~xample 2.

~ ' , .

-10- , , .:

~756~

Example 5 7-Amino~3-[[(1-methyl-lH-te-trazol-5-yl)thio]methyl]-8-oxo-5-thia-l-azabicyclo[4.2.0]oct~2-ene-2-carboxylic acid, diphenyl-methyl_ester The product, 7-amino-3-[[(1-methyl-lH-tetrazol-5-yl)-thio]methyl]-8~oxo-5-thia-1-azabicyclo~4.2.0]oct-2-ene carboxylic acid, diphenylmethyl ester, m.p. 168-169 ~dec.), is obtained ; by the procedure of Example 4 utilizing as starting material 7-amino-3-[[tl-methyl-lH-tetrazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid.
Example 6 a) 7~-[[[[[(4-~ethoxyphenyl)methoxy]carbonyl]amino]phenylacetyl]-; amino]-3-[[(1-methyl-1~1-tetrazol-5~yl)thio]me-thyl]-8-oxo-5-thia-l-azabicyclo~4.2.0]oct-2-ene-2-carboxylic acid, diphenylmethyl ester 3~78 g. (0.012 mol.) of [[[(4-methoxyphenyl)methoxy]-carbonyl]amino]benzeneacetic acid (prepared as described in UOS. Patenk 3,560,489~ February 2, 1971) are dissolved in 100 ml.
of tetrahydrofuran and added to a solution of 4.95 g. ~0.01 mol.) of 7-amino-3-l[(l-methyl-1ll-tetrazol-5-yl)thio~methyl]-8-oxo-5-thia-l-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, diphenyl-methyl ester in 50 ml. of methylene chloride. The mixture is cooled to 0-5 and at this temperature a solution of 2.27 g.
(0.011 mol ) of dicyclohexylcarbodiimide is added dropwise.
The mixture is stirred for 90 minutes at 0-5 and 90 minutes at room temperature. The precipitated dicyclohexylurea (2.4 g.) is filtered off. The filtrate is concentra-ted and the residue is taken up in a mixture of ethyl acetate and tetrahydrofuran (3:1). The organic phase is washed once with sodium bicarbonate solution and twice wi-th water, then decolorized with activated ~' 3L~7567~3 carbon, dried with magnesium sulfate, filtered and concentrated to a small volume. The precipitated product is filtered under suction. 5.5 g. of 7~-[~[[[(4-methox~phenyL)methoxy]carbonyl]-amino]phenylacetyl]amino]-3-[[(l~methyl-lH-tetrazol-5-yl)thio]-methyl] 8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, diphenylmethyl ester, are obtained, m.p. 145-150 (dec.).
By concentrating the mother liquor and adding ether, an additional 0.7 g. of product is obtained.
b ~
~y~l)thio]meth~1~-8-oxo-5-thia-1-azab _yclo[4.2.0]oct-2-ene-2-carbox lic acid, trifluoroacetate sal-t - --Y
3.7 g. of the product of part a are added at 0-5 to a mixture of 74 ml. of trifluoroacetic acid and 22 ml. of anisole. After 10 minutes, the trifluoroacetic acid is evaporated under vacuum and ether is added to the residue.
2.6 g. of 7~-[(aminophenylacetyl)amino]-3-[[(1-methyl-lH-tetrazol-5-yl)thio]methyl-8-oxo-5-thia-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, trifluoroacetate salt, m.p. 135 (dec.) is obtained.
Example 7 D-a-l E [ (4-methoxyphenyl )methoxyl c arbonyl ] amino-2- thlopheneacetic acid 8.0 g. of magnesium oxide are suspended in 200 ml.
of water. 15.7 g. of D-2-(2-thienyl)glycine are added to the suspension followed by a solution of 22.8 g. of p-methoxy-benzyloxycarbonylazide in 200 ml. dioxane. The mixture is stirred for 3 days at room temperature.
The reaction mixture is then filtered andthe filtrate is extracted once with 125 ml. of diethyl ether. The ether layer is then discarded. The aqueous phase is cooled to .

',' . , : - , :

~7567~

5-10 , layered with about 150 ml. of ethyl acetate and acidified with 2N hydrochloric acid to pH 2.5. After separating the layers, the aqueous phase is extracted agaln with 100 ml. of ethyl acetate. The combined ethyl acetate solutions are washed once with water, dried over magnesium sul~ate and evaporated. The oily residue crystallizes on treatment with petroleum ether. The yield amounts to 30.8 gms. of crude material. After recrystalli-zation from ethyl acetate/petroleum ether, 2S.2 gms. of D-cl-[~[(4-methoxyphenyl)methoxy]carbonyl]amino]-2-thiopheneacetic acid are obtained, m.p. 66-69. The material is usually contaminated with a small amount of ethyl acetate which cannot be removed at 35 in vacuum. The material obtained free from ; ethyl acetate has a melting point 66-69 la~25 = -70 (c = 1, tetrahydrofuran).

Example 8 7~-[[[[[(4-methoxyphenyl)methoxy]carbonyl]aminol-(2-thienyl)-acetyl]amino3-3-[[~1-methyl-lH-tetrazol-5~yl)thio]methyl3-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, diphenylmethyl ester The product of Example 7 and 7-amino 3-[[(1-methyl-lH-tetrazol-5-yl)thio]methyl-8-oxo-5-thia-1-azabicyclo[4.2.0]-oct-2-ene~2-carboxylic acid diphenylmethyl ester are dissolvecl in 650 ml. of absolute tetrahydrofuran and the solution is cooled to 0. At this temperature, a solution of 7.3 gms.
of dicyclohexylcarbodiimide in 60 ml. of absolute tetrahydro-furan is added dropwise over a periocl of about 20 minutes.

The mixture is st.irred at 0 for two hours and an addi-tional two hours at room temperature. The dicyclohexylurea which precipitates is removed by fil-tra-tion. 'rhe filtrate is concsntrated in vacuum. The residue is ciissol.vccl in elhyl ~75679 GG231 acetate, washed with saturated sodium bicarbonate solution, then with water and dried with magnesium sulfate. After filtration, the filtrate is left overnight in the refrigerator. The reaction product crystallizes. On filtration 12.2 gms. of [[[[[(4-methoxyphenyl)methoxy]carbonyl]amino~-2~(2-thienyl)acetyl]-amino]-3-[[(1-methyl-lH-tetrazol-5-yl)thio]methyl]-8-oxo-5-thia-l-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid,diphenylmethyl ester are obtained, m.p. 126 (dec.). The filtrate is evaporated to dryness. Treatment with ethyl acetate yields a second crop of 2.6 gms. A third crop of 2.6 gms. is obtained when the filtrate is evaporated, dissolved in a small amount of ethyl acetate, precipitated with petroleum ether and again treated with ethyl acetate.
Example 9 7-lD-2-amino-2-(2-thienyl)acetamido]-3-[[(l-methyl-lH-tetra sol-5-yl)thio3methyl]-8-oxo-S-thia-l-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, trifluoroacetate salt . .
11.5 gms. of the product of Example 8 are mixed with ~ 30 ml. of anisole, cooled to 0-5 and 150 ml. of trifluoro-acetic acid are added. The solution is stirred for 10 minutes at this temperature. Then the solvent is stripped off in vacuum and the residue is -treated with diphenyl ether. 8.6 gms.
of 7-lD-2-amino-2-(2-thienyl)acetamido~-3-[[(l-methyl-lEf-tetrazol-5-yl)thio~methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, trifluoroacetate salt are obtained.
Example 10 7-[D-[2-(3-methyl-2-thioureido)-2-(2-thienyl)]acetamido]-3-~[Il-methyl-lEl-tetrazol-5-yl?thio]methyll-8-oxo-5-thia-l-aza-k~ cl~l4.2.~]oct-2-ene-2-car}~oY~lic acid - 30 1.74 'l~ ~0-0()3 mol.) ot 7- [I~-2-amino-2-(2-thicnyl)acctamido]-.

:' 3-~[(1-methyl-lH-tetrazol-5-yl)thio]methyl]~8-oxo-5-thia-1-azabicyclo[4.2.0~oct-2-ene-2-carboxylic acid, trifluoroacetate salt are added -to 40 ml. of methylene chloride and 0.8 ml. of tri-ethylamine is added to the suspension. A clear solution forms.
A solution of 0.33 g. of methylisXlli~cyanate in 10 ml. oE methylene chloride is added and the mixture is permitted to react for

4 hours at room tempera-ture. The reaction mixture is then concentrated and the residue is dissolved in water. The aqueous solution is extracted with ethyl acetate, the phases are separated and the aqueous phase is acidified to pH 1.5.

The precipitate is filtered under suction to obtain 0.7 ~. of 7-~D-2-1(3-methyl-2-thioureido~-2-(2-thienyl)acetamido~-3-[[(l-methyl-lH-tetrazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, m.~. 169-171 (dec.).
Example 11 , .
j 3-[[~5-Methyl-1,3,4-thiadiazol-2-yl~thio~methyl]-7-amino-7a-methoxy-8-oxo-5-thia-1-azabicyclo[4 ~ -2-carboxylic acid A mixture of 15.1 g. (0.05 M) of 7-amino-7-methoxy-cephalosporanic acid in 100 ml. of water and 50 ml. of acetone are brought to pH 8 with sodium hydroxide while stirriny.
7.5 g. (0.057 M) of 2-methyl-1,3,4-thiadiazole-5-thiol are added and the mixture is heated at 80 for four hours. After cooling to 5 , this is acidified to pH 3.5 with dilute hydro-chloric acid and stirred for 15 minu-tes. The precipitated solid is filtered under suction and washed with acetone. This 3-~1(5-methyl-1,3,4-thiadiazol-2-yl)thio]methyl]-7-amino-7a-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid i.s purifiea by dissolvin(~ in sodium bicarbonate solution and repreci~itatinq with 2~ hydrochloric acid.

,, ~, :

~.~7567~

Example 12 3-[[(3-~ethyl-1,2,4-thiadiazol 5-yl)thio]meth~l]-7-amino-7a-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid By substituting 3-methyl-1,2/4-thiad:iazo:Le,5-thiol for the 2-methyl-1,3,4-thiadiazole-5-thiol in the procedure of Example 11,3-~[(3-methyl-1,2,4-thiadiazol-5-yl)thio]methyl~-7-amino-7a-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acld is obtained.
Example 13 3-[[(1-Methyl-lH-tetrazol-5-yl)thio~methyl]-7-amino-7~-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid __ .
By substituting 0.057 M of l-methyl-lll-tetra~ole-5-thiol for the 2-methyl-1,3,4-thiadia%ole-5-thiol in the procedure of Example 11,3-[[~1-methyl-llg-tetrazol-5-yl)thio]-methyl]-7-amino-7a-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]-. : .
oct-2-ene-2-carboxylic acid is obtained.
,~ Example 14 7-Amino-7~-methoxy-3-[[(5-metl~yl-1,3,4-thiadiazol-2-yl)thio]-methyl~-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, diphenylmethyl ester 18 g. of 7-amino-7a-methoxy-3-[[~5-methyl-1,3,4-thiadia-zol-5-yl~thio]methyl]-8-oxo-5-thia-l-a2abicyclol4.2.0]oct-2-.
ene-2-carboxylic acid are suspended in 350 ml. of tetrahydro furan. 4.1 ml. of 70% perchloric acid are added dropwise. After 30 minutes, a slightly turbid solution forms. This solution is filtered and to the filtrate is added dropwise with stirring 12 g. of diphenyldiazomethane and 20 ml. of tetrah~drofuran. ~ ~-After 3 hours, the reaction mixture is poured into 2 liters of absolute ether. The solid, light brown precipitate, which ~ -16-.; : , ~7567g is the perchloric acid salt of the desired product, is dried over Kieselgel in a desiccator. To obtain the base, the perchloric acid salt is dissolved in ~later and treated with the calculated equivalent of potassium bicarbonate. The aqueous solution obtained is extracted with chloroform. The chloroform phase is treated with activated carbon and sodium sul~a-te to obtain the product, 7-amino-7a-methoxy-3-[[(5-methyl-1,3,4-thiadiazol-2-yl)thiolmethyl]-8-oxo-5-thia--l-azabicyclo[4.2.0]-oct-2-ene-2-carboxylic acid, diphenylmethyl ester. The product is recrystallized from tetrahydrofuran/petroleum ether.
7-Amino-7a-methoxy-3 [[(3-methyl-1,2,4-thiadiazol-5-yl)-thio]methyl]-7-amino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, diphenylme-thyl ester is similarly obtained by substituting the product of Example 12.
Example 15 7-Amino-7a-methoxy-3~[[(1-methyl-lH-tetrazol-S-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, --diphenylmethyl ester .
The product, 7-amino-7a-methoxy-3-[[(1-methyl-lH-tetra-zol-5-yl)thio~methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, diphenylmethyl ester, is obtained by the procedure o Example 4 utilizinc~ as starting material 7-amino-7a-methoxy-3-~[(1-methyl-lH-tetrazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid.
Example 16 a) 7a-MethoxY-7~-[[[[[~4-methoxyphenyl)methoxy]carbonyl]-amino]phenylace-tyl~amino]-3-[[(1-methyl-lH-tetrazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acld, d p ~ lmethyl ester 3.78 g. (0.012 mol.) of ~[~4-methoxyphenyl)methoxy]-.. :

.

, ~07 5679 GG231 carbonyl]amino]benzeneacetic acid (prepared as described in U.S. Patent 3,560,489, February 2, 1971) are dissolved in 100 ml.
of tetrahydrofuran and added to a solution of 5.27 g. (0.01 mol.) of 7-amino-7a~methoxy-3-[[(1-methyl-lH-te-trazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, diphenylmethyl ester in 50 ml. of methylene chloride. The mixture is cooled to 0-5 and at this temperature a solution of 2.27 g. (0.011 mol.) of dicyclohexylcarbodiimide is added dropwise. The mixture is stirred for 90 minutes at 0-5 and 90 minutes at room temperature. The precipi~ated dicyclohexyl-urea is filtered off. The filtrate is concentrated and the residue is taken up in a mixture of ethyl acetate and tetra-hydrofu~an (3:1). The or~3anic phasl! is washed onc~ with sodium bicarbonate solution and twice wi-th water, then decolorized with activated carbon, dried with magnesium sulfate, dried and concentrated to a small volume. The precipitated product is filtered under suction. 7a-methoxy-7~-[[[[[(4-methoxy-phenyl)methoxylcarbonyllamino~phenylacetyl]amino]-3-[[(1-methyl-tetrazol-S-yl)thio]methyl]-8-oxo-5-thia-l-azabicyclo[4.2.01 oct-2-ene-2-carboxylic acid, diphenylmethyl ester, is obtained.
By concentrating the mother liquor and adding ether, additional product is obtained.
b) 7~-[~Aminophenylacetyl)amino]-7a-methoxy-3-1[(]-methyl-lH-tetrazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo-4-2 O]oct-2-ene-2-carboxylic acid, triflu oacetate salt 3.7 g. of the product of part a are added at 0-5 to a mixture of 74 ml. trifluoroacetic acid and 22 ml. of anisole.
After 10 minutes, the trifluoroacetic acid is evaporated under vacuum and ether is added to the residue to obtain 30 7~- [ (aminophenylacetyl)amino]-7a-methoxy-3-[[(1-methyl-lH-.
-]8--, ~07 5679 GG231 , tetrazol-S-yl)thio]methyl-8-oxo-5-thia-1-azabicyclo[4.2.0]-oct-2-ene-2-carboxylic acid, tri~luoroacetate salt.
Example 17 7a-methoxy-7~-[[~[[(4-methoxyphenyl)methoxy]carbonyl]amino]-2-thienyl)acetyl~amino]-3-[[(1-methyl-1~-tetrazol-5-yl)thio]
methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-c _ boxylic acid, diphenylmethyl ester :
The product of Example 7 and 7-amino-7a-methoxy-3-[[(1-methyl-lH-tetrazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo-[4.2.0]oct-2-ene-2-carboxylic acid, diphenylme-thyl ester are dissolved in 650 ml. of absolute tetrahydrofuran and the solution is cooled to 0. At this temperature, alsolution of 7.3 gms.
of dicyclohexylcarbodiimide in 60 ml. oflabsolute tetrahydro-furan is adde~ dropwise over a period oflabout 20 minutes. The ; mixture is stirred at 0 ~or two hours and an additional two ~ hours at room temperature. The dicyclohexylurea which preci-; pitates is removed by filtration. The filtrate is concentrated in vacuum. The residue is dissolved in ethyl acetate, washed with saturated sodium bicarbonate solution,lthen with water and dried with magnesium sulfate. After filtration, the filtrate is le~t overnight in the refrigerator. The reaction product crystallizes. On filtration 7a-methoxy-7~-[[[[[(4-methoxyphenyl)-methoxylcarbonyl]amino]-(2-thienyl)acetyl]amino]-3-[[~1-methyl-lH-tetrazol-5-yljthio3methyl]-8-oxo-5-thia-1-azabicyclo[4~2.0]-oct-2-ene-2-carboxylic acid, diphenylmethyl ester is obtained.
Example 18 7~-~D-2-Amino-2-(2-th lH-tetrazol-5-yl)thio]methyl]-8~oxo-5-thia-1-azabicyclo[4.2.0]-oct-2-ene-2-carboxylic acid, trifluoroacetate salt 11.5 gms. of the product of Example 17 are mixed with 30 ml. ;

- .
-: --19-- :, 107 5~79 GG231 of anisole, cooled to 0-5 and 150 ml. of trifluoroacetic acid are added. The solution is stirred for 10 minutes at this temperature. Then the solvent is stripped off in vacuum and the residue i5 treated with diethyl ether to obtain 7~-[D-2-amino-2-(2-thienyl)acetamido]-7a-methoxy-3-[[(1-methyl-lH-tetrazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, trifluoroacetate salt.
Example 19 a-methoxy-7~-ED-2-[~(3-methyl-2-thioureido)-2-(2-thieny~
acetamido~-3-1[(1-methyl-lH-tetrazol-5-yl)thio]methyl]-8-oxo-5-thia-l-azabicyclo[4.2.O]oct-2-ene-2-carboxylic acid The product of Example 18 is reacted with methylisothio-cyanate in methylene chloride in the presence of triethylamine according to the procedure of Example 10 to obtain 7a-methoxy-7~-[D-2-[[(3-methyl-2-thioureido)-2-~2-thienyl)]acetamido-3-[[(l-methyl-lH-tetrazol-5-yl)thio}methyl]-8-oxo-5-thia-1-, azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid.
~, Example 20 7a-methoxy~7~-[D-2-t[(3-methyl-2-thioureido)-2-~2-thienyl)]-acetamido]-3-[[(1-methyl-lH-tetrazol-5-yl)thio]methyl~-8-oxo-thia-1-azahicyclo~4.2.0]oct-2-ene-2-carboxylic acid, sodium salt O.Sl g. of the product o Example 19 are brouyht into ~ solution with 10 ml. of a 0.1 N sodium bicarbona~e solu~ion and ,; the clear solution is freeze dried. A quantitative yield of,: ~
the sodium salt is obtained.
Example 21 7-[D-[2-(3-methyl-2-thloureido)--2-(1,4-cyclohexadien-1-yl)-cet~llrli-loJ 3-[[(1-methyl-]1l-te ra7.0] _- ~ thyll=8-oxo ; - S-th~ ~a ~ 4.2.0lOC~-2~ 2-car~ xylic_a _d 1~ 30 Following the procedure ol~ I.xamplc 7 but substitutin~
:':
,:

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~075679 GG231 D-2-(1,4-cyclohexadien-1-yl)glycine for the D-2-(2-thienyl)-glycine and continuing with the procedure of Examples 8 through 10, the above named product i5 obtained.
Examples 22-51 Similaxly, following the procedure of either Examples 7 through 10 or Examples 7 and 17 through 19, but substituting for the D-2-(2-thienyl)glycine in Example 7 the compound in Column A, and substituting for the methylisothiocyanate in Examples 10 or 19 the isothiocyanate in Column B, the product IO in Column C is obtained. :~

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Col. A Col. B Col C

Rl-CH-COOH R2NCS R S
NH 2 Rl - CH - C- NH ~ N --IIN
NH 6~N ~-CH2S N ,N
C= S COOH 3 Exampl e R Rl R2 24 2 5 -CH2-CH=CH2 H t-C4Hg H

; li2 H2 27 ~S ~L H2C/ \CH-C--C
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34 -OCH3 ~ ~
H ~ CH2- H

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~ 39 H H3C
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Claims (4)

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 R1 is 2-thienyl; R2 is lower alkyl; R3 is hydrogen or a salt forming ion; and R4 is 1-methyl-1H-tetrazol-5-yl, characterized by reacting a compound of the formula wherein the symbols are as previously defined, with an isothiocyanate of the formula R2-N=C=S

wherein R2 is lower alkyl.

2. A process according to claim 1 wherein 7-[2-amino-2-(2-thienyl)acetamido]-3-[[(1-methyl-1H-tetrazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene carboxylic acid is reacted with methylisothiocyanate to form 7-[[2-(3-methyl-2-thioureido)-2-(2-thienyl)]-acetamido]-3-[[(1-methyl-1H-tetrazol-5-yl)thio]metthyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid.

3. A compound of the formula wherein R1 is 2-thienyl; R2 is lower alkyl; R3 is hydrogen or a salt forming ion; and R4 is 1-methyl-1H-tetrazol-5-yl, whenever prepared by the process of claim 1.

4. A compound according to claim 3 wherein R2 is methyl and R3 is hydrogen, whenever prepared by the process of claim 2.