IE46431B1 - Cephalosporins - Google Patents

Abstract

Cephalosporins of the formula I in which R<1> represents alkyl having 1 - 4 C atoms and n is 1, 2 or 3, and non-toxic, pharmaceutically utilisable salts and esters thereof are obtained by reaction of an appropriate cephalosporin, which carries an acetoxymethyl group in the 3-position of the ring system, with an appropriate mercaptotetrazole compound. In an alternative process, this reaction is carried out using a cephalosporin having a free amino group, this being appropriately acylated in a second step. The compounds can be used in pharmaceutical compositions for the control of bacterial infections, such as Haemophilus or Neisseria infections.

Description

The cephalosporins of the present invention in general possess the usual attributes of such compounds and are particularly useful in the treatment of bacterial infections .

Prior known cephalosporins include those disclosed in Patent Specification No. 38172 having the general formula wherein RU is phenylj naphthyl; thienyl; furyl, benzothienyl; benzofuryl; pyridyl or any of these groups substituted by halo io (chloro, bromo, iodo or fluoro), hydroxy, lower alkyl, nitro, amino, loweralkylamino, diloweralkylamino, lower alkanoyl, lower alkanoylamino, lower alkoxy, lower alkylthio or carbamoyl; R Is lower alkyl; cycloalkyl containing 3-7 carbon atoms; carbocyclic or heterocyclic aryl lower alkyl or any of these groups substituted by hydroxy, carboxy, esterified carboxy, amido, cyano, alkanoyl, amino, substituted amino, halogen or lower alkoxy; and Y is selected from acetoxy; a group of formula where Rd and n are as defined In claim 19; a group of for20 mula -SW where W is thiadiazolyl, diazolyl, triazolyl, tetrazolyl, thiazolyl, thiatriazolyl, oxazolyl, oxadiazolyl, ίο benzimidazolyl, benzoxazolyl triazolopyridyl, purinyl, pyridyl or pyrimidyl; an alkylthio group containing 1-4 carbon atoms; a group of formula -O.CO.R^ where E? is an alkyl or alkenyl group containing 2-4 carbon atoms; the group -O.CO.NH.(CHg)mD wherein m is an integer of from 1-4 and D is chlorine, bromine, iodine or fluorine; and azido) and non-toxic salts and esters thereof. Methods for the preparation of the starting acids used to form the 7-substituent, including their separation into syn and anti isomers, are also described therein and in British Patent Specification No. 1,404,221.

Presently issued U.S. patents 5,966,717 and 3,971,778 contain at least part of the disclosure of British Patent Specification No. 1,599,086 as does U.S. 5,974,155. See Also Farmdoc abstracts 17270X and 19177X.

U.S. 5,974,155 claims compounds of the formula C3_7 cycloalkyl or phenyl; and a physiologically acceptable salt thereof.

For examples of publications in the scientific literature see Ryan et al., Antimicrobial Agents and Chemotherapy, 9, 520-525 (1976) and 0'Callaghan et al., ibid, 5H-519 (I976) and Norby et al., ibid, £, 506510 (1976).

U.S. 5,819,625 discloses the conversion of the 2-mercapto-l,5,4-thladiazole-5-acetic acid to 7-(lHtetrazol-l-yl-acetamido)-5-(5-carboxymethyl-l,5,4-thia25 diazol-2-ylthiomethyl)-3-cephem-4-carboxylic acid and see also Farmdoc abstract 12921T.

U.S. 3,883,520 and 2,931,160 and Farmdoc abstract 2285OW make reference to 3-heterocyclicthiomethyl cepha5 losporlns containing a number of substituents (including carboxyl) on the numerous heterocycles included but these references are completely general in nature and include no physical constants, yields, methods of synthesis or the like and do not even name any such compound containing a carboxyl substituent. See also Farmdoc 00145W.

U.S. 3,928,356 provides a review of much of the older cephalosporin art.

Farmdoc abstract 1883OX discloses compounds of the' formula compounds of the present invention are not described therein or in the full text of the corresponding patent. See also Farmdoc abstract OI98IX. 6 4 31 One of the problems presently facing the medical profession at this time was described by Arnold L. Smith, M.D. in an article titled Antibiotics and Invasive Haemophilus influenzae, N. Engl. J. Med., 294(24), 1329-1331 (June 10, 1976) in which the opening sentence reads as follows: Recently, the information service of the Center for Disease Control, the Medical Letter and the American Academy of Pediatrics have sounded the alert that invasive strains of Haemophilus influenzae isolated throughout the United States have been found to be resistant to ampicillin, many of the isolates being associated with treatment failure.

His concluding paragraph reads: The current situation portends a dismal future for the antibiotic treatment of invasive H. influenzae disease. An H. influenzae resistant to the second-line drug, chloramphenicol, has been described, and, more recently, an untypable H. Influenzae resistant to chloramphenicol and tetracycline was isolated from tne throat of a four-year-old girl. Thus, both these currently efficacious agents may not be useful in the future.

The present invention seeks to provide a solution to this problem.

The present invention thus provides compounds having the formula II often written herein as (CH2)nC00H II (CH2)nC00H wherein R^ is a.lkyl containing 1-4 carbon atoms, n is one, 2 two or three and R is pivaloyloxymethyl, acetoxymethyl, methoxymethyl, acetonyl, phenacyl, p-nitrobenzyl, β-β-βtrichloroethyl, 3-phthalidyl or 5-indanyl.

As set forth below in more detail the present invention also provides salts of the compounds of formula I. The stereochemistry of the bicyclic nucleus is that found in Cephalosporin C.

The compounds of the present invention are syn isomers or else are mixtures of syn and anti isomers containing at least 75% of the syn isomer. Preferably such mixtures of isomers contain at least 90% of the syn isomer and not more than 10% of the anti isomer.

Most preferably the compounds are syn isomers essentially free of the corresponding anti isomer.

Reference to the syn (cis) isomeric form refers to the configuration of the group OR*· with respect to the carboxamido group. 6 4 31 The present invention also provides a process for the production of a compound of formula I which comprises reacting a compound of the formula CH, Ν' II OOH (CH^COOH wherein n is one, two or three or a salt or appropriate ester of Schiff base (as with benzaldehyde or salicylaldehyde) thereof with an organic monocarboxylic acid chloride or a functional equivalent thereof as an acylating agent selected to give the corresponding free acid of the compound of formula I, and thereafter converting the free acid to a corresponding ester or a non-toxic pharmaceutically acceptable salt thereof.

Such functional equivalents Include the corresponding acid anhydrides, including mixed anhydrides and particularly the mixed anhydrides prepared from stronger acids such as tlie lower (i.e. having 1 to 6 carbon atoms) aliphatic monoesters of carbonic acid, or alkyl and aryl sulfonic acids and of more hindered acids such as diphenylacetic acid. In addition, an acid azide or an active ester or thioester (e.g, with p-nitrophenyl, 2,4-dinitrophenol, thiophenol, lo thioacetic acid) may be used or the free acid itself may be coupled with compound II after first reacting said free acid with N,N’-dimethylchloroformiminium chloride [cf. Great Britain 1,008,170 and Novak and Weichet, Experientla XXI. 6, 360 (1965)] or by the use of enzymes or of an N,N*-carbonyldiimidazole or an Ν,Ν’-carbonylditriazole [cf.

South African patent specification 63/2684] or a earbodiimide reagent [especially N,N*-dicyclohexylcarbodiimide, Ν,Ν'-diisopropylcarbodiimide or N-cyclo20 hexyl-N'-(2-morpholinoethyl)carbodiimide; cf. Sheehan and Hess, J, Amer, Chem, Soc.. 77. 1967 (1955)], or of alkylylamlne reagent [cf. R. Buijle and H.G.

Viehe, Angew, Chem. International Edition 3, 582, (1964)] or of an isoxasolium salt reagent [cf. R. B. Woodward, R. A. Olofson and H. Mayer, J. Amer, Chem.

Soc.. 83, 1010 (1961)], or of a ketenimine reagent [cf. C. L. Stevens and Μ. E. Munk, J. Amer, Chem. Soc., 80. 4065 (1958)] or of hexachlorocyciotriphosphatriazine or hexabromocyclotriphosphatrlazlne (U.S. 3,651,050) or of dlphenylphosphoryl azide [DPPA; J,., Amer.,, Chem.. Soc., 94, 6203-6205 (1972)] or of diethylphosphoryl cyanide [DEPC; Tetrahedron Letters No. 18, pp. 1595-1598 (1973)] lo or of diphenyl phosphite [Tetrahedron Letters No, 49, PP· 5O47-5O5O (1972)]. Another equivalent of the acid chloride is a corresponding azollde, i.e., an amide of the corresponding acid whose amide nitrogen Is a member of a quasiaromatic five membered ring containing at least two nitrogen atoms, i.e., imidazole, pyrazole, the triazoles, benzimidazole, benzotriazole and their substituted derivatives. As an example of the general method for the preparation of an azollde, Ν,Ν'-carbonyldlimidazole is reacted with a carboxylic acid in equimolar proportions at room temperature in tetrahydrofuran, chloroform, dimethylformamide or a similar inert solvent to form the carboxylic acid imidazolide in practically quantitative yield with liberation of carbon dioxide and one mole of imidazole. Dicarboxylic acids yield dimidazolide. The by-product, imidazole, precipitates and may be separated and the imidazolide Isolated, but this is not essential. The methods for carrying out these reactions to produce a cephalosporin and the methods used to isolate the cephalosporin so produced are well known ln the art. 6 431 ίΟ Mention «as made above of the use of enzymes to couple the free acid with compound II. Included In the scope of such processes are the use of an ester, e.g. the methyl ester, of that free acid with enzymes provided by various microorganisms, e.g. those described by T. Takahashi et al., J. Amer. Chem. Soc., o4(ll). 4035-4.037 (1972) and by T. Nara et al., J. Antibiotics (japan) 24(¾-). 321-323 (1971) and in U.S. 3,682,777. io For the coupling of the organic carboxylic acid as described above with compound II (or a salt or preferably an easily hydrolyzed ester of Schiff base, as with benzaldehyde, thereof) it is also convenient and efficient to utilize as the coupling agent phosphonitrilic chloride trimer (J. Org. Chem., 33(7). 2979-81, 1968) or N-ethoxy1,2-dihydroquinoline (EEDQ) es described in J. Amer. Chem. Soc., 90. 823-824 and 1652-1653 (1968) and U.S. Patent 3,455,929. The reaction is preferably carried out at SO35 °C. in benzene, ethanol or tetrahydrofuran using about '20 equimolar quantities of all three reagents followed by conventional isolation and removal by conventional methods of any blocking groups present.

An additional process of the present invention comprises the preparation of the compounds of the present invention by the displacement of the 3-acetoxy group of a 7-acylaminocephalosporanic acid (prepared by substituting 7-amino46431 -Ύ. cephaloeporanic acid for che 3-thiolated-7-aminocephalosporanic acids ln Che acylation procedures described herein and elsewhere reported) with a Chlol HSR? having the formula N HS aJ (CH,) COOH wherein n is one, two or three and then removing the protecting group if any is present, as on the carboxyl group.

The displacement of such a 3-acetoxy group with such a thiol may be accomplished in solution as in water or aqueous acetone at a temperature of at least room temperature and preferably within the range of about 50* to 100*C. in the presence of a mild base such as sodium bicarbonate, e.g. preferably near neutrality such as at about pH 6, An excess of the thiol is preferably employed. The reaction product is isolated by careful acidification of the reaction mixture followed by extraction with a water-immiscible organic solvent. As noted above, the preparation of many other 7-acylamidocephalosporanic acids is described in the patent and scientific literature, e.g. in U.S. Class 260-243C. @431 The salts of the compounds of this invention include the nontoxic carboxylic acid salts thereof, including nontoxic metallic salts such as sodium, potassium, calcium and aluminum, the ammonium salt and substituted ammonium salts, e.g. salts of such nontoxic amines as trialkyl-amines including triethylamine, procaine, dibenzylamine, N-benzyl-beta-phenethylamine, 1-epheneamine, Ν,Ν'-dibenzylethylenediamine, dehydroabietylamine, N,N'bis-dehydroabietylethylenediamlne, and other amines which have been used to form salts with benzylpenicillin, L-lysine, arginine and histidine.

The present invention thus also provides the process for the production of compounds of formula I which comprises reacting a compound of the formula c N.

OR Λ ιι I II C-CH O-C-CH3 II COOR‘ ,2 wherein R , n, and R are as described above or the corresponding free acid, with a compound having the formula NHS· ii (CH2)nC0°H wherein n is one, two or three and in the case of the free acid converting the resulting compound to the required ester or a non-toxic pharmaceutically acceptable salt thereof The preferred esters of the cephalosporins of the present invention are the pivaloyloxymethyl, acetoxymethyl, methoxymethyl, acetouy and phenacyl esters.

As indicated above, these five esters of 7-aminocephalosporanic acid are each prepared by known methods.

One excellent procedure is that of U.S. patent 3,284,451 in which sodium cephalothin is esterified by reaction with the corresponding active chloro or bromo compound (e.g. phenacyl bromide, chloroacetone, chloromethyl ether, pivaloyloxymethyl chloride /also called chloromethyl pivalate7, acetoxymethyl chloride) and then the thienylacetic acid sidechain is removed enzymatically as in the same patent or chemically as in U.S. patent 3,575,970 and in Journal of Antibiotics, XXIV (11), 767-773 (1971). In another good method the triethylamine salt of 7-aminocephalosporanic acid is reacted directly with the active halogen compound, as in British Patent Specification No. 1,229,453.

These esters of 7-aminocephalosporanic acid are 3 then reacted with the nucleophilic HSR in the same manner as is illustrated herein for 7-aminocephalosporanic acid itself. The 3-thiolated ester of 7-aminocephalosporanic acid is then coupled with the organic carboxylic acid as before.

In another alternative synthesis, the 3-thiolated 7-aminocephalosporanic acid is prepared as described herein and then acylated at the 7-amino group and finally esterified, as by reaction of the appropriate alcohol with the acid chloride prepared, for example, by reaction of the final cephalosporin with thionyl chloride or by other essentially acidic esterification procedures.

In the treatment of bacterial infections in man, the compounds of this invention are administered parenterally in an amount of from about 10 to 90 mg./kg./day and preferably about 14 to 50 mg./kg./day in divided dosage, e.g. two to four times a day. They are administered ih dosage units containing, for example, 125, 250 or 500 mg. of active ingredient with suitable physiologically acpeptable carriers or excepients.

The dosage units are in the form of liquid preparations lo such as solutions or suspensions and preferably are aqueous solutions of a sodium or potassium salt Which are injected intravenously or intramuscularly or by continuous or intermittent infusion in concentrations of about 125-500 mgm./ml., and preferably, 250 mgm./ml. as is customary in therapy with cephalosporin antibiotics. /16 4 31 l-Carboxvmethvl-5-mercaptotetr?zole Ν-Ν I! ιι HS - vN CHgCOOH a) Recrystallization of l-methyl-5-mercaptotctmata icaaeduca: 1. One hundred and ten grams of l-methyl-5 mercaptotetrazole is slurried in 350 ml. of boiling chloroform. A near solution is obtained. 2. The hot solution (50-608) is rapidly io filtered by vacuum through a heated Buchner funnel (11 cm. SS No. 604 paper containing 1/4 to 1/3 inch of packed filter aid (Supercel- Trade Mark).

The filter pad is washed with 50 ml. of 5O-6O°C. chloroform which is added to the filtrate. 3, The filtrate is cooled to approximately 0-6’ C. and kept at 0-6’ C. for 2 hours. The crystals which have formed are collected by filtration at 0-6’ C. and washed with 60 ml. of 0-6* C. chloroform which is added to the filtrate.

The crystals (cut A) are air dried at 37-45° C. for l8 hours. ι6 4. Bie filtrate la concentrated on the rotary vacuum evaporator (60® C. bath) to approximately one-half volume. Thia elurry ia cooled to 0-6® C, and kept at 0-6® C. for 2 hours. The crystals are collected by filtration at 0-6® C., washed with 4o ml. of 0-6® 0. chloroform which is added to the filtrate. The crystals (cut B) are sir dried at 37-45® C, for 18 hours. Crystal cuts A and B are composited to give an approximate 65# weight yield.

. The filtrate of cut B, Step 4 may be reworked twice as described in Step 4 to obtain an additional 15# recovery. b) Preparation of the Dl-sodlum Salt of 1.carboxvmethvl-5“mercaptotetra2ole Procedure; 1. Five hundred ml. of substantially dry and pure tetrahydrofuran in a 2-liter 3 neck flask with stirrer is cooled in a salt-acetone-lce bath to approximately -10® C. Dry nitrogen gas is blown on the liquid surface. 2. Five hundred ml. of 15.06# (1.6 jj) butyl lithium in hexane (Foote Mineral Co.) is added over a ten minute period under dry nitrogen and stirring to the tetrahydrofuran. The near solution is cooled to -5 to -10® C. 3. Forty six and four tenthe gram (46.4 g.J of l-methyl-5-mercaptotetrazole (recrystallized as above) Is dissolved ln 200 ml. of substantially pure and dry tetrahydrofuran. The solution Is filtered lf cloudy and then cooled to 5 to 10® C, 4, The cooled solution of step 3 Is added over 10 minutes with stirring and under dry nitrogen to the butyl lithium solution. The temperature should be maintained at -5® C. to *10® C, maximum. io Precipitates may form. ' 5. The mixture is stirred under dry nitrogen and 0* C. to +10® C. for one half hour. 6. Anhydrous carbon dioxide gas is bubbled through at a rapid rate and with rapid stirring for 153O minutes at approximately ambient temperature (0 to 10® C.) to no higher than +20® C. 7. The white precipitate which forms is suitably collected by filtration in an area of low humidity. The precipitate is washed with about 75 ml· of tetrahydrofuran. 8. The precipitate is dissolved in 250 ml. of water (pH 8.5“9·5). A second layer of tetrahydrofuran may be present. This may be removed in the vacuum rotary evaporator (50® C. bath). tr* + 9. The aqueous solution Is adjusted to pH 1.6-2.0 with concentrated hydrochloric acid.

. The acid aqueous solution is extracted twice with 25Ο ml. portions of ethyl acetate. ' Each 250 ml. ethyl acetate extract Is back extracted with 100 ml. portions of water. The water extracts are discarded. The ethyl acetate extracts (free of any water layer) are filtered end composited. 11. The combined ethyl acetate extracts are concentrated to dryness on the vacuum rotary evaporator (60° C. bath). 12. The crystals in the flask are boiled with 300 ml. of chloroform for about 2 minutes. The hot slurry (50-60° C.) is .vacuum filtered.through a heated Buchner funnel (11 cm-SS-604 paper). The crystals are washed with about 75 ml, of 50’ C. chloroform. The crystals are air dried at room temperature for about 3 hours and then made about 100-200 mesh. 13. The 100-200 mesh crystals are treated with boiling chloroform exactly as described in step 12 (the hot chloroform removes most of the unreacted l“methyl-5-mercaptotetrazole). Yield: approximately 45 to 50 grams of crystalline 1carboxymethyl-5-mercaptotetrazole. These crystals 431 ι9 may contain 0.02 to 0,05 moles of l-methyl-5mercaptotetrazole. 14. The crystals of step 13 are slurried with 250 ml. of ethyl ether at room temperature for 35 minute8. The mixture is filtered. The insolubles (0.5-5/0 may be a contaminating symmetrical mercaptotetrazole ketone of the following tentative structure: N-=rN 0 N-==-N I j II II N^ XN - CHg - C - CH, - Νχ C C 1 SH SH CAUTION: This compound EXPLODES at approximately 205-210’ C.

. The ether filtrate of step 14 is evaporated to dryness on the vacuum rotary evaporator (50** C, bath). Approximately 42 to grams of crystalline l-earboxymethyl-5-mercapto15 tetrazole containing approximately 0.01-0.05 mole of l-methyl-5-mercaptotetrazole is recovered. 16. The crystals are dissolved in 420 ml. of absolute ethanol (approximately 100 mg./ml.).

The solution is warmed to 50-60’ C. 17. To the hot solution of step 16, 310 ml. of a 4l# sodium 2-ethyltiexanoate (SEH) solution in isopropanol is added with very rapid stirring over a 10 minute period. A crystalline precipitate forms. The mixture ie slurried at 50-60’ C. for minutes. 18. The mixture Is filtered hot (50-60* C.) through a heated Buchner funnel (ll cm-SS-No. 604 paper). She crystals are washed with 75 ml. of 50’ C, ethanol. 19, lhe ethanol damp crystals of step 18 are slurried In 200-500 ml. of ethanol. The slurry Is passed through a 200 mesh ecreen. The slurry Is heated to 50-60* 0. for 5 minutes with rapid stirring (unreacted mono-sodium l-methyl-510 mercaptotetrazole is very soluble In hot ethanol). . 20, The crystals are collected at 50-60’ 0. on a 11 cm-SS No. 604 paper In a heated Buchner funnel. The crystals are washed with 75-100 ml. of ethanol and vacuum dried at 50-60*' C. for 15 24-48 hours. Yield: 40-48 grams of di-sodlum l-earboxymethyl-5-mercaptotetrazole (free of 1methyl-5-mereaptotetrazole as observed by NMR), 2ί 7-Amlno-3-fl-carboxymethyltetra2ol-q-?lthlomethyl)-3-cePhem-4-carhoxylic. acid.

COgH 1. Into a 3 necked flask set up with an agitator, a temperature regulator,thermometer and a nitrogen Inlet tube, place 18 grams (0.066 mole) of 7-aminocephalosporanic acid, (whloh has preferably been recrystallized by the toluenesulfonle aeld procedure) and 300 ml. of 0.1 M pH 6.4 phosphate buffer (20.7 grams of sodium phosphate, monobasic .lHgO ♦ 8.5 grams of sodium phosphate, dibasic, anhydrous, q.s. to 2 liters). 2. With agitation of the mixture described In step 1, add 1.5 grams of sodium bisulfite and 16 grams (0.078 moles) of 1-carboxymethyl-διό mereaptotetrazole disodium. 3. With agitation continuing, bubble nitrogen through the mixture for 10 minutes. 4. Maintaining agitation and nitrogen Inflow, heat the slurry over a 20 minute period to 56° C. During this time interval, 6.5 grams of sodium bicarbonate Is added in small Increments . With continued agitation and nitrogen Inflow, maintain the temperature of the solution at 56° C. for 4 hours. The pH should remain at between 6.2 - 6.6. 6. Cool the reaction mixture in an Ice bath to 5’ C. 7. Add 50 ml. of a 1:1 phosphoric acid/water solution to the mixture or concentrated HCl to a pH of 2.0 - 3.0. 8. Collect the product by filtration. Wash the filter cake with 20 ml. of cold water followed by 200 ml. of cold methanol. 9. Air dry the solid to constant weight.

(A typical run produced 14.5 grams of product.) This product may vary in color from yellow to dark brown.

. Pass the product through a 200 mesh stainless steel screen. 11. Suspend 10 grams of the 200 mesh powder in 200 ml. of n-propanol with rapid stirring. 12. Add 2.0 ml. of concentrated hydrochloric lo acid and stir vigorously for 0.5 hour at room temperature. 13. Filter the slurry. Wash the brown solids with 20 ml, of n-propanol and add the wash to the filtrate (save the filter cake for possible recovery of additional product). 14. Add 1.5 grams of charcoal (Darco (3-60 - Darcois a Trade Mark) to the n-propanol filtrate of step 13. Slurry. for 0.5 hour. Remove the carbon by filtration. · Wash the carbon with 20 ml. of n-propanol and add the wash to the filtrate, . With rapid stirring, add triethylamine to the n-propanol filtrate to an apparent pH of 3.0.

Crystals form. Slurry for 10 minutes 16. ' Collect the white crystals by filtration 25 and wash with 30 ml. of n-propanol, 50 ml. of methanol, and vacuum dry at 4o° C, for 24 hours.

Yield: 4 to 8 grams of 7-amino-3-(l-carboxymethyltetrazol-5-ylthlomethyl)-3cephem-4-carboxylic acid. 17. An alternate procedure for the purification of 7-fimifto“3“(l-carboxylmethyltetrazol-5ylthiomethyl)-3-cephem-4-carboxylic acid follows: a) Slurry 10 grams of the 200 mesh product (from step 10) in 75 ml. of 1 hydrochloric acid for 10-15 minutes at room temperature. Filter to remove dark brown solids. b) Add 2.5 grams of charcoal (Darbo O-6o) and slurry for 0.5 hour. a) Remove the carbon by filtration. Wash the carbon with 15 ml. of water and add the wash to the filtrate. d) With rapid stirring, add concentrated ammonium hydroxide to the filtrate to pH 2.515 3.0, Crystals form. e) Slurry the crystal mass for 25 minutes. Remove the crystals by filtration. Wash the crystals with 3θ ml. of water,. 50 ml. of methanol, and vacuum dry at room temperatures Yield: 4-7 grams of near white crystals.

Preparation of l-CarboxyethyItetrazol-5-thlol N>-N HS-Ajj^N (ch2)2-C02h A) 2-Carboethoxyethylisocyanate β-alanine ethyl ester hydrochloride (93.6 g.), triethylamine (123.5 g.) and methylene chloride (400 ml.) 5 were mixed together and cooled to -10° C. Carbon disulfide (46.5 g.) dissolved in 150 ml. of chloroform was added to the above solution during a two-hour period while keeping the temperature at about -10* C. After the addition was complete, the temperature was allowed to warm to 10° C. for about 10 minutes. The solution was again cooled to -10* C. and 66.3 g. of ethyl chloroformate in 6o ml. cf chloroform was added dropwise over a 40-minute period with stirring. The temperature was allowed to rise to room temperature for 30 minutes and again cooled to 0* C.; an additional 6l.6 g. of triethylamine was added at 0° C. and then the solution was stirred at room temperature for 3 hours.

The mixture was treated with water and the organic phase collected, washed with 2 x 250 ml. of sn HCl, then 2 x 250 ml. of NaHC03, then 2 x 250 ml. of water. The organic phase was dried over NagSO^ and the solvent removed in vacuo to produce 93-7 g· of an oil found to be the desired product. The IR and NMR spectra were consistent with the structure.

B) l-Carboxyethyltetrazol-5-thlol Sodium azide (29.7 g.) was dissolved in 400 ml. 6 4 31 of water and heated to 60’ C. in a nitrogen atmosphere. 2-Carboethoxyethylisocyanate (46.9 g.) dissolved in 50 ml. of Skellysolve B (essentially n-hexane) was added to the heated sodium azide solution. The so5 lutlon was stirred for about 150 minutes at about 70-72“ C., then cooled to 30° C. in an ice bath. Fifty percent sodium hydroxide solution was added until the pH was 12. The mixture was heated for 40 minutes at 70° C. and cooled to 15“ C. in an ice bath. The pH was adjusted to 2 using concentrated HCl and then extracted with ethyl acetate (4 x 150 ml.). The ethyl acetate extracts were washed with water, then dried ove-r sodium sulfate. The solvent was evaporated in vacuo and the product was collected as crystals from methylene chloride to yield I9.5 g. of title product.

Alternative Synthesis of l-Carboxyraefchyl-5-mercapfcotetrazole +CS2 + NaN3 -¾¾-> I ^N-CH2C02H + Na2S + C2H50H 4643 1 To a stirred mixture of 13.95 g (0.10 m) of glycine ethyl ester hydrochloride, 8.0 g. (0.20 m.) of sodium hydroxide and 8.37 g |0.11 ra) of carbon disulfide was added a solution of 7.47 g (0.115 m) of sodium azide in 125 ml of water. The solution was heated at reflux for 6 1/2 hrs. and stored IS hrs. at 25°. The dark brown mixture was filtered and the filtrate acidified to pH 1.5 with cono. hydrochloric acid. The solution was io carbon treated and the yellow filtrate was extracted 4 χ 100 ml with ethyl acetate. The ethyl acetate was washed with water, dried over magnesium sulfate and evaporated at 40° (15 mm) to an oil. The oil was triturated with methylene chloride and the product was collected. The sample was dried in vacuo over phosphorus pentoxide for 16 hrs. at 25*. The ir and nmr spectra were consistent for the structure.

Reference: German Patent 106645.

Preparation of 5-Mercaptotetrazole-l-acetlc Acid From 2-Carboethoxymethyl Isothiocyanate S CH2-NHa ® 2 (02%)3Ν CHg-NH-C-SH cs.

C-0C2H5 .(CgHgJj 0,¾ I2 5 O-C-Cl CHgCNS Joc2h5 CH, -NH-C-S-C- OC,H I 2 Η II 2 C-ΟΟ,Η- S 0 II 2 5 NaN, I|J—N - CHgCOgCgHg n;w^-»sh OH NJ-N - CHgCOgH SH Carboethoxymethyl Isothiocyanate 2 Carbon disulfide (22.8 g., 0.3 mol.) in chloro· form (40 ml.) was added over a period of one hour to a stirred suspension of glycine ethyl ester hydrochloride (41.7 g. 0.3 mol.) and triethylamine (60.7 g., 0.6 mol.) in methylene chloride (300 ml.) at -10° C. The reaction mixture was allowed to warm up to 10° C. and was stirred » for 10 minutes at this temperature. The mixture was treated dropwise with ethyl chloroformate (32.6 g., 0.3 mol.) in chloroform (50 ml.) at 0-5° C. over a period of .5 hour. The mixture was stirred for another 40 minutes at room temperature and triethylamine (30*4 g., 0.3 mol.) was added dropwise over a period of 15 minutes. The mixture was stirred for 1/4 hour at 0’ C. and an additional 1/2 hour at room temperature and finally stored over night at 25° C. The mixture was washed with water (250 ml.), 2N hydrochloric acid (2 x 300 ml.), 5# sodium bicarbonate solution (4 x 300 ml.) and dried over anhydrous sodium sulfate. The solvent was evaporated at 40° C. (15 mm.) to yield 38.1 g. of crude isothiocyanate. Upon storage overnight, a red dye was produced. This may be eliminated by distillation of the isothiocyanate.* -Mercaptotetrazole-l-acetic acid J, To a solution of sodium azide (4.9 g., 0.075 mol.) in water (100 ml.) heated to 60° C. under nitrogen, was added the isothiocyanate (7.3 g., 0.5 mol.) over a period of 1/4 hour. The mixture was heated at 70-75° C. for 2 hours, cooled to 5° C. and 50$ sodium hydroxide was added to pH 12. The solution was heated to 75° C. for 1 hour, cooled to 5° C. and adjusted to pH 2 with concentrated hydrochloric acid and filtered through diatomaceous earth (Supercel). The solution waa extracted with ethyl acetate (4 x 120 ml.), carbon treated and evaporated to an oil at 30°C. (15 mm.). The residue was slurried with chloroform to yield 1 g. of acid. The nmr and ir spectra were identical with authentic 5-mercaptotetrazole-l-acetic acid.

*The isothiocyanate may be distilled at 104-106° c. (7 mm.) T.B. Johnson and A.G. Renfrew, JACS 47 240-245 (1925) ” l-Carboxypropyl-2-mercaptotetrazol«.

To a solution of 40.8 g. (0.63 mole) of Sodium azide in 400 ml. of waCer at 60*C. was added 66.8 g. (0.42 mole) of methoxycarbonyl propyl isothiocyanate [D.L, Garmaise, et al., J. Amer. Chem. Soc., 80, 3332 (1958)] dropwise. The mixture was heated at 78*C. for 2 hours, cooled to room temperature and adjusted to pH 12 with 50Z sodium hydroxide solution. Th· solution was then heated at reflux for 1-1/2 hours, eooled to 27*C. and adjusted to pH 2 with 6N hydrochloric acid. The mixture waa filtered through diatomaceous earth (!lDicalite~ Trade Mads) and the cake was washed with 100 ml. of ethyl acetate. Ihe filtrate was extracted with 4 x 100 ml. of ethyl acetate.· The extracts were combined, washed with water and dried by azeotropic distillation to precipitate an oil which crystallized on cooling in an ice-bath to yield 22 g. l-carboxypropyl-2mareaptotetrazole. The nmr spectrum was consistent for the structure. 7-Amine-3-(l-carboxypropvltetrazol-5-ylthiomethyl)-3eephem-4-carboxylie Acid.

To a suspension of 22 g. (0.081 mole) of 7aminecephalosporanic acid in 350 ml. of pH 6.4 0..1H I phosphate buffer was added 16.9 g. (0.089 mole) of 1carboxypropyl-5-mercaptotetrazole and 1.5 g. of sodium bisulfite. The mixture was heated under nitrogen to 55*C. 6 4 31 and solid sodium bicarbonate was added until the mixture became clear (pH 7.5). The solution was heated for 3.5 hours, cooled to 10*C. and adjusted to pH 2 with 6N hydrochloric acid. The precipitate was collected, washed with cold water end finally with methanol and air-dried to yield 17.5 g. of 7-amino-3-(l-carboxypropyltetrazol-5ylthiomethyl)-3-eephem-4-earboxylie acid. The sample was recrystallized from 100 ml. of methanol with concentrated hydrochloric acid added dropwise until the mixture was io clear. The solution was adjusted to pH 5 with concentrated ammonium hydroxide and the precipitate was collected to yield 6.7 g, The nmr and ir spectra were consistent for the structure.

Preparation of 7-Amino-3-fl-carboxypropyltetrazolyl-515 thiomethyl)-3-cephem-4-carboxylie Acid.

II cs HgNCHgCHgCHgC-OCH^’HCl + (CgH^N CH -> CHOCH„C - OCH, | 2 2 3 ch2-nh2- c - s CgHgO-C-Cl © (c2h5)3nh CH2CH2C-0CH3 I„NH-C-S-C3 CH2NH-C-S-C-0C2H5 CHOCHGC-OCH, | -2 2 3 ch2-n=c=s NalL Ϊ'Τ' .

V II NaS-C^u1· (l/NaOH 3} HCl (ch2)3co2ch3 H:-:H ι ι HS (2)3co2h SH L—it-(ch2)3co2h -> Δ U-Butyrylmethoxy Isothiocyanate.

To a mixture of 153.6 g. (1.0 mole) of 4-aminobutyric acid methyl ester hydrochloride 202.4 g. (2.0 mole) triethylamine and 600 ml. of methylene chloride cooled to -15° C. was added 76,1 g. (1.0 mole) of carbon disulfide in 200 ml. chloroform during a 60-minute period. The mixture was warmed to 10° C., stirred 10 minutes, cooled to 0° C. and 108.5 g, (1.0 mole) of ethyl chloroformate in 80 ml. of chloroform was added during a 20-minute period (0-5° C.) The mixture was stirred without ice bath for 70 minutes and warmed to l8° C. The reaction was again cooled to 0° C. and 101,2 g. (1.0 mole) of triethylamine was added during a 20-minute period. The reaction was stirred for 15 minutes at 0° C. then for 1.5 hours without the ice bath.

The mixture was washed with 250 ml. of water, x 300 ml. of 2N hydrochloric acid, 2 x 300 ml. of 5# sodium bicarbonate and 2 x 300 ml. of water. The organic phase was dried over anhydrous magnesium sulfate and 6431 reduced in volume 15 mm. to a yellow oil. Yield: 126 g. oil. The ir was consistent for the structure. l-Carboxypropyl-5-mercaptotetrazole To 40.8 g. (Ο.65 mole) of sodium azide in 400 ml. of water at 60° C. under a brisk nitrogen flow was added dropwise 66.8 g. (0.42 mole) of N-butyrylmethoxy isothiocyanate. The reaction was warmed at 78° C. for 2 hours under nitrogen. The reaction was cooled to 25° C., 50# sodium hydroxide was added to pH 12 and the mixture was refluxed for 1.5 hours and then cooled. The mixture was adjusted to pH 2 using 6n hydrochloric acid (caution: hydrogen azide). The mixture was filtered through Super-cel and the cake was washed with ethyl acetate. The washings were added to the filtrate and the phases were separated. The aqueous fraction was extracted into 4 x 100 ml. of ethyl acetate and the organic fractions were combined. The organic phase was washed with water, dried over anhydrous magnesium sulfate and reduced in volume at 350 C. (15 mm.) to an oil which was allowed to stand in an ice bath. The product was collected and dried in vacuo over PgO^ at 25° C. Yield: 22 g. off-white solid. The nmr was consistent for structure. 7-Amino-3-(l-earboxypropyltetrazolyl-5-thlomethyl)-5cephem-4-carboxylic Acid.

To a nitrogen purged solution of 1.5 g. (1.4 x IO2 mole) of sodium bisulfite in 350 ml. of pH 6.4 phosphate buffer was added 22 g. (8,1 x 10“2 mole) of 7-aminocephalosporanic acid, 16.85 g. (9·θ x 10 mole) of l-carboxypropyl-5-mercaptotetrazole and enough sodium 6 4 31 bicarbonate to fora a clear solution. The reaction was warmed for 3.5 hours at 560 C. under a brisk nitrogen flow, then cooled to 10° C. The pH was adjusted to 2.5 using 6n hydrochloric acid and the mixture was stirred in an ice bath to aid precipitation. The product was. collected and then washed with cold water, methanol and acetone.

The product was recrystallized from methanolhydrochloric acid and dried in vacuo over P„0,. at 25° C. --d 5 lo yield: 6.7 g. The ir and nmr were consistent for the structure.

I 2-Furoylcyanide To a suspension of 26.1 g. (0.4 mole) of ground potassium cyanide in 300 ml. of acetonitrile at 5° C. was added 26.1 g. (0.2 mole) of α-furoyl chloride while keeping the temperature below 8° C. The mixture was stirred in the cold for 15 minutes then heated at reflux for 30 minutes. The reaction was cooled, filtered and the acetonitrile was removed at 15 mm. (steam-bath) leaving 24.5 g. of a dark oil which was used without further purification.

An Infrared spectrum showed a nitrile band at 2265 cm-1. 2-Furaneglyoxyllc Acid The 24.5 g. of crude 2-furoylcyanide was mixed with l60 ml. concentrated hydrochloric acid at 25° C. with intermittent stirring. The reaction was stored for 24 hours at 25° C. and diluted with 80 ml. of water. The reaction was stirred for 5 minutes and filtered. The filtrate was saturated with sodium chloride and extracted with 5 x 120 ml. of 1:1 ether-ethyl acetate solution. The extracts were combined, dried over anhydrous magnesium sulfate and evaporated at 30° C. (15 mm.) to give a brownish-orange solid. The solid was dissolved in methanol, treated with charcoal and evaporated under reduced pressure (15 mm.) to dryness to yield 17 g. of the acid.

The product was recrystallized from toluene to give 11.5 g. (m.p. 760 C.). The ir and nmr spectra were consistent for the structure. 2-Methoxylmino-2-furylacetic Acid To a solution of 4.5 g. (0.032 mole) of 2-furaneglyoxylic acid in 40 ml. of 50# alcohol and 3.1 g. (0.037 4© 431 mole) of methoxyamine hydrochloride in 6 ml. water at 20* C. was added dilute sodium hydroxide solution to pH 4-5.

The solution was stirred at pH 4-5 at 25® C. for 24 hours. The alcohol was removed under reduced pressure (15 mm.) and the solution was adjusted to pH 7-8 with sodium hydroxide solution. The reaction was extracted with 3 x 50 ml. of ether and the aqueous layer was adjusted to pH 1.9 using concentrated hydrochloric acid. The mixture was extracted with 5 x 50 ml. of ethyl acetate. The organic io fractions were combined, washed with brine, dried over anhydrous magnesium sulfate and evaporated under reduced pressure (15 mm.) to an oil which was cooled for one hour in an ice bath. The product was slurried with Skellysolve B and collected to yield 3.1 g. of yellow crystals, m.p. 7θβ C. An analytical sample was recrystallized from toluene, dried for l6 hours in vacuo over ?2°5 ai: 25° c· The ir and nmr spectra were consistent for the structure.

Anal. Calc'd for C^NO: C, 49-65; H, 4.17; N, 8.28. Pound: C, 49.30; H, 4.21; N, 8.37. 7-Amino-3-(l-carboxyethyltetrazol-5-ylthiomethyl)-3cephem-4-carboxyllc Acid To a mixture of 5 g. (0.0286 mole) of 5-mercaptotetrazolyl-proplonlc acid and 7.8 g. (0.0286 mole) of 7-aminocephalosporanic acid in 150 ml. of ,1M phosphate buffer (pH 6.4) was added with stirring solid sodium bicarbonate until the solution became clear (pH 7.5).

The solution was heated at 55* C. under nitrogen for 4 hours and acidified with 1:1 H^PO^. The precipitate was collected, washed with water and finally with a small volume of methanol. The solid was then slurried with 150 ml. of methanol and concentrated hydrochloric acid added dropwise until the.mixture became clear. The solution was treated with carbon, filtered and neutralized with concentrated ammonium hydroxide to pH 4.5· The solid was collected, washed with methanol to weigh 5.2 g. m.p. >130° C. decomp., The ir and nmr were consistent for the structure. 2-Ethoxyiminofurylacetlc Acid The 7.85 g. (Ο.Ο56 mole) of furyl-2-glyoxylic acid was dissolved in 100 ml. of water and adjusted to pH 7 with 50# sodium hydroxide. The 6.83 g. (0.070 mole) of ethoxyamine hydrochloride in 10 ml. of water was added, while keeping the pH at 4-5· The reaction was diluted with 25 ml. of alcohol, stirred 3 hours at room tempera15 ture and then filtered. The alcohol was removed at 35° C. (15 mm.) and the aqueous portion was adjusted with dilute sodium hydroxide solution to pH 7-8 and then was washed with ether and the washes were discarded. The aqueous fraction was adjusted with 6h hydrochloric acid to pH 1.5 and extracted into J x 80 ml. of ethyl acetate. The acetate fractions were combined, washed with brine and reduced in volume at 35° C. (15 mm.) to an oil. The oil was cooled in an ice bath, triturated with Skellysolve B, collected and dried over PgO^ in vacuo at 25° C.

Yield: 4.8 g., m.p. 83-850 C. The ir and nmr were consistent for the structure.

Anal. Calc'd for CgH^iC^: C, 52.46; H, 4-95; N, 7.65. Pound: C, 52.22; H, 4.94; N, 7.60.

Sodium g-Ethoxyimlno-a-f2-furyl)acetate To 50 ol. of methanol was added 250 og. (0.0109 mole) of metallic sodium and stirred until all the sodium had dissolved. This sodium methoxide solution was treated 5 with 2.0 g. (O.OIO9 mole) of a-ethoxyimino-a-(2-furyl)acetic acid dissolved in 10 ml. of methanol and stirred at room temperature for one hour. The methanol was removed at 40° C. (15 mm.) and the product was dried in vacuo over PgOg at 25° C. to yield 2.22 g. white solid, m.p. decomp. >240° C. The ir and nmr were consistent for the structure.

Skellysolve B Is a petroleum ether fraction of b.p. 6o°-68° C. consisting essentially of n-hexane.

PREPARATION. OF INTERMEDIATES PREPARATION I 7-(2-Methoxylmino-2-furylacetamido)-3-(1-carboxyethyltetrazolyl-5-thiomethyl)-3-cephem-4-carboxylic Acid (BL-S1O95) A suspension of 75θ mg. (0.0039 mole) of sodium 2-methoxyiminofuryl-acetate in 25 ml. of benzene and 2 drops of dimethylformamide was stirred vigorously while 0.35 ml. (0.0039 mole) of oxalyl chloride was added dropwise.

The suspension was stirred for 45 minutes and the salts which formed were recovered by filtration. The benzene was removed at 40° (15 mm.) and the light yellow oil was dissolved in 20 ml. of acetone and added to a solution of 1.6 g. (0.0039 mole) of 7-amino-3-(l-carboxyethyltetrazol-5-ylthiomethyl)-3cephem-4-carboxylic acid in 25 ml. of water and 5θθ ing· of sodium bicarbonate at 5° C. The solution was stirred for 1/2 hour at 5° C. and the acetone was evaporated under reduced pressure at 40° C. (15 mm.) diluted with 25 ml. of water and acidified with 1:1 phosphoric acid. The mixture was extracted with 3 x 50 ml. of ethyl acetate and the organic layer was separated, washed with water and evaporated to a gummy residue. After the solid was slurried with ether, the free acid was dissolved in acetone and treated with 750 mg. of potassium '2-ethylhexanoate. The potassium salt was collected, washed with acetone and dried over PgO,_ to give 800 mg. m.p. >130° C. slow decomp.

Anal. Calc'd for C^H^K^N^Sg · 1-1/2 HgO: C, 37.21; H, 3.52; N, 15-90. Pound: C, 37.17; H, 3.515 N, 13.89. nmr (DgO ppm S) 7-75, d, 1, -CH-OO; 6.95, d, 1, =CH-CH=; 6.6-6.8 m., 1=CH-CH=; 5-83, d, 1, N-CH-; 5.25 d, 1, -CH-S; 4.6, T, 2, N-CHg-CHg-COgH; 4.0-4.6 M2=C-CH2-S0j 4.0, S, 3, N-OCH-; 3-3-4.0 m 2 S-CH2-C=j 2.85, T, 2, CH2-C02H. ir (KBr cm-^) 3100-3600, OH, NH, 1765 B-lactam carbonyl;, 1675 MHC^ 1600 C02.

PREPARATION 2 7-(2-Methoxyimino-2-furylaeetamido)-3-(l-carboxymethyltetrazolyl-5-thiomethyl)-3-cephem-4-carboxyllc Acid (BL-S1080) To 25 ml. of methanol was added 100 mg. (0.00425 mole) of metallic sodium and the mixture was stirred until all of the sodium had dissolved. The sodium methoxide solution was cooled to 3° C. and 0.179 S· (0.00425 mole) of methoxyiminofurylacetic acid in 5 ml. methanol was added. The solution was stirred for 10 minutes at room temperature and the solvent was evaporated at 30° C. (15 mm.) and dried by azeotropic distillation with 3 x 20 ml. of benzene (15 mm.).

The sodium 2-aethoxyimino-2-furyl-acetate was suspended in 25 ml. of benzene and treated with 4 drops of dry dimethylformamide. A total of 1.1 g. (0.0085' mole) of oxalyl chloride was added and solution was stirred for 40 minutes at 25° C. The benzene was removed at 35° C. (15 mm.) and the acid chloride was dissolved in 10 ml. acetone. A solution of 1.2 g. (0.0032 mole) of 7-amino3-(l-carboxymethyltetrazolyl-5-thiomethyl)-3-cephem-4carboxylic acid in 20 ml. of water and 0.68 g. (0.0081 mole) of sodium bicarbonate was cooled to 3° C. The acetone solution of the above acid chloride was added and the reaction was stirred for 40 minutes without the ice bath. The acetone was removed at 30° C. (15 mm.) and the aqueous solution was adjusted to pH 1.8 using 6n 464 31 hydrochloric acid. The product was extracted with 3 x 60 ml. of ethyl acetate. The organic fractions were combined, washed with brine and azeotroped at 30° C. (15'mm.) to an amorphous solid. The residue was treated with 50 ml. of ether and the product was collected and dried in vacuo over P„0_ to yield 750 mg. of a light tan solid, m.p. >120° C. decomp. Anal. Calc'd for H20: C, 42.17; Η, 4.θ6; N, 17.20. Found: C, 42.16; H, 3.96; N, 16.66. The nmr spectra showed the compound to be a mixture of 75# syn and 25# anti Isomers with diethyl ether as an Impurity or solvate. The syn pattern is listed below: nmr (DMSO ppm S) 9-75 d, 1 C-NH-J 7-75, S, 1, =CH-O-; -6.8 m, 2, =CH-CH=; 5-6-5-9, m, 1, N-CH-; 5-3, 5, 2, N-CHg-C15, d, 1, -CH-S; 3-95-4.65 m 2, CH2-S, 3-9, S 3 OCH^; 4-4.0 m, 2, -S-CH2-C=.

Separate anti patterns: 9.55 d, 1, -CO-NH-; 7.25 d, 1, =CH-CH=; 4.0, S, 3, OCHy PREPARATION 3 7-(2-Methoxyimlnofurylacetamido)-3-(l-carboxypropyltetrazolyl-5-thiomethyl)-3-cephem-4-carboxylle Acid. (BL-S1081) N-OCH.

To 25 ml. of methanol was added 96 mg. (4.16 x 10”^ mole) of metallic sodium which was stirred until all of the sodium had dissolved. This sodium methoxide solution was cooled to 3® C. and 704 mg. (4.16 x 10”^ mole) of co2h (5 d 3 i 2-methoxyiminofurylacetic acid in 5 ml. of methanol was added. The reaction was stirred for 10 minutes at room temperature, the methanol removed at 35° C. (15 mm.) and the sample was azeotroped with 3 X 30 ml. benzene at 55° 5 C. (15 mm.).

To a stirred suspension of the above sodium 2-methoxyiminofurylacetate in 25 ml. of benzene with 3 drops of dimethylformamide was added 1.06 g. (8.3 x 10”R mole) oxalyl chloride and stirred 1 hour at room temperature. The benzene was removed at 35° C. (15 mm.) and the acid chloride was dissolved in 10 ml. of acetone.

The acid chloride solution was added to a solution of 1.28 g. (3.2 x 10? mole) of 7-amino-3-(l-carboxy~ propyl-tetrazolyl-5-thiomethyl)-3-cephem-4-carboxylic acid I5 and 0.672 g, (8 x 10“·^ mole) sodium bicarbonate in 25 ml. of water at 3° 0. The solution was stirred 40 minutes with the ice bath removed. The reaction was filtered, the acetone removed at 30° C. (15 mm.) and the aqueous fraction was adjusted to pH 1.8 with 6ϊί HCl. The sample was layered with ethyl acetate and then filtered through Super-cel, The phases were separated and the aqueous phase was further extracted with 3 x 30 ml. of ethyl acetate. The organic fractions were combined, treated with charcoal, filtered through Super-cel, then azeotroped at 30° C., (15 mm.) to an amorphous solid. This residue was triturated with excess ether and the product collected, dried over PgO^ at 25° C. yielding 370 mg. of an offwhite solid. M.p. dec. >83° C. The ir and nmr were consistent for the structure.

PREPARATION 4 7-f 2-Ethoxyimino-2-(fur-2-yl) acetamido]-3-(1-carboxymethyltetrazolyl-5-thiomethyl)-3-eephem-4-carboxyllc Acid Synisomer. (BL-S11O5) UC - C - NH II n-oc2h5 .Ν_χ4-0Η2-3-0χκχΝ COgH n:—tn !l II CHCOgH To a stirred suspension of 1.1 g. (5.3 x 10 mole) of sodium a-ethoxyimino-a-(2-furyl)acetate in 40 ml. of benzene with 6 drops of dimethylformamide was added 706 mg. (5.57 x 10“5 mole) of oxalyl chloride and stirred for one hour at room temperature. The benzene was removed 1° at 40° C. (15 mm.) and the acid chloride was dissolved in 5 ml. of acetone.

The acid chloride solution was added to a solution of I.89 g. (5.08 x 10-5 mole) of 7-amino-3-(lcarboxymethyltetrazolyl-5-thiomethyl)~3-cephem-4-carboxylic acid and 1.28 g. (1.52 x 10 mole) of sodium carbonate in 40 ml. of water at 3° C. The reaction was stirred for 40 minutes, filtered and the acetone removed at reduced pressure at 35° C. (15 mm.). The aqueous solution was layered with ethyl acetate, adjusted to pH 1.9 with 40# phosphoric acid and filtered. The phases were separated and the aqueous portion was extracted with 2 x 60 ml. of ethyl acetate. The ethyl acetate fractions were combined, washed with brine, dried over anhydrous magnesium sulfate and reduced In volume to an oil at 35° C. (15 mm.). The oil was layered with excess ether and allowed to stand at •a ** room temperature for l6 hours. The product was collected and dried in vacuo over PgO,. at 25° C. to yield 800 mg. tan solid. M.p. dec. >75° C.

Anal. Calc * d for C^gH^gNyOgS^'l/S^CgH^gO: C, 5 43.905 H, 4.295 N, 17.06. Found; C, 43.9Ο5 H, 4.24; N, 16.21.

The ir and nmr were consistent for the structure of a hemi diethyl etherate.

PREPARATION 5 10 substitution of an equimolar weight of sodium 2-ethoxyimino-2-(fur-2-yl)acetate for.the sodium 2-methoxyiminofuryl acetate used in the procedures of Examples 1 and 2 produces 7-(2-ethoxyimino-2-furylacetamido)-3-(1-carboxyethyltetrazol-5-ylthiomethyl)-315 cephem-4-carboxylic acid and 7-(2-ethoxyimino-2-furylacetamido)-3-(l-carboxymethyltetrazol-5-ylthiomethyl)-3eephem-4-carboxylic acid, respectively.

PREPARATION .6 Substitution of an equimolar weight of sodium 2-n-propoxyimino-2-(fur-2-yl)acetate for the sodium 2-methoxyiminofuryl acetate used in the procedures of Examples 1 and 2 produces 7-(2-n-propoxyimino-2-furylacetamido)-3-(1-carboxyethyltetrazol-5-ylthiomethyl)-3cephem-4-CarboxylIe acid and 7-(2-n-propoxyimino-2-furyl25 acetamido)-3-(l-carboxymethyltetrazol-5-ylthiomethyl)-3cephem-4-carboxylie acid, respectively. 6 4 31 PREPARATION 7 Substitution of an equimolar weight of sodium 2-n_butoxyimino~2-(fur-2-yl)acetate for the sodium 2-methoxyimlnofuryl acetate used in the procedures of Examples 1 and 2 produces 7-(2-n-butoxyimino-2-furylacetamido)-3-(l-carboxyethyltetrazol-5-ylthiomethyl)-3cephem-4-carboxylic acid and 7-(2-n~butoxyimino-2-furylacetamido)-3-(l-carboxymethyltetrazol-5-ylthiomethyl)-3cephem-4-carboxylic acid, respectively.

PREPARATION 8 The products of Examples 1-7 are prepared as syn isomers essentially free of the corresponding anti isomers by the use in the procedures of those examples of purified syn isomers of the appropriate 2-alkoxyimino-2-(fur-2-yl)~ acetic acid. Conversion of part of the syn isomer to anti isomer during preparation of the acid chloride from the acid is substantially avoided by minimizing its exposure to hydrogen chloride, e.g. by first converting the acid to Its anhydrous sodium salt and by treating that salt with oxalyl chloride under anhydrous conditions in the presence of a hydrogen ion acceptor such as dimethylformamide.

PREPARATION 9 7-(2-Methoxyimino-2-furylacetamido)-3-(1-carboxymethyltetrazolyl-5-thiomethyl)-3-cephem-4-carboxylic Acid (BL-S1080) To 3.0 g. (0.0156 mole) of sodium 2-methoxyimino2- furyl acetate suspended in 60 ml. of benzene was added 6 drops of dimethylformamide and 1.98 g. (0.0156 mole) of oxalyl chloride. The resulting solution was stirred at 25°C. for 45 minutes. The benzene was removed at 40°C. (15 mm.) and the acid chloride was dissolved in 4 ml. of acetone. A solution of 5.8 g. (0.0156 mole) of 7-amino3- (l-carboxymethyltetrazolyl-5-thiomethyl)-3-cephem-4carboxylic acid and 2.5 g. (0.03 mole) of sodium bicarbonate in 80 ml. of water was cooled to 3°C. and the acid chloride solution was added. The reaction mixture was stirred for 20 minutes at 3°C. and 20 minutes with ice-bath removed. A pH of 7 was maintained while stirring.

The mixture was filtered and the acetone removed at 35°C. (15 mm.). The aqueous portion was layered with ethyl acetate, adjusted to pH 1.8 with 6N hydrochloric acid and extracted 2 x 80 ml. with ethyl acetate. The organic fractions were combined, washed 2 x 40 ml. with brine, dried over anhydrous magnesium sulfate and evaporated at 35°C. (15 mm.) to an amorphous solid which was triturated with ether. The free acid was collected and air dried to yield 4.5 g. The acid was dissolved in acetone and treated with 1.2 g. (0.0065 mole) of potassium 2-ethylhexanoate dissolved in acetone. The product was collected and dried in vacuo over ?2θ5 at 25°C. to yield 2.49 g. of the potassium salt.

M.p. >130°C. slow decomp. The nmr spectra indicated the compound to be a mixture of 95% syn and 5% anti isomers.

Analysis Calc'd for C^gH^gKNyOgSgS C, 38.49; H, 2.87; K, 6.96; N, 17.45. Founds C, 38.06; H, 2.68; K, 6.65; N, 17.34.

PREPARATION 10 Preparation of BL-S1080 R-H, BL-S1080 £ R-Na, 8L-S1080 & 6 4 31 2-Furoylcyanide 1.

To a suspension of 78.3 g. of powdered potassium cyanide in 900 ml. acetonitrile at 5° C. was added 59.25 ml. (68.5 g.) of α-furoyl chloride with vigorous stirring whilekeeping the temperature at 4-8° C. The mixture was stirred at 4-8° C. for 15 minutes and then heated at reflux for 30 minutes. The mixture was cooled to 23-25° C., filtered, washed with 50 ml. of acetonitrile which was added to the filtrate, and the acetonitrile was removed at 60° C. (15 mm.) leaving 51 g. of as a dark oil. An IR spectrum showed a nitrile band at 2265 cm-·1· and an NMR spectrum showed a ratio of approximately 70/30 of product Ji/furoic acid. The crude product^ was used without further purification (49# yield of product).

Furyl-2-glyoxylic Acid 2.

The 51 g. of crude 2-furoyl cyanide ^1 was mixed with 500 ml. concentrated hydrochloric acid at 25° C. The reaction was stirred for 24 hours at 25° C. and then diluted with 240 ml. of water. The mixture was stirred for 5 minutes and filtered. The black filtrate was saturated with sodium chloride and extracted with 6 x 500 ml. of 1:1 ether-ethyl acetate solution. (Note: Initially the extractions were difficult due to the inability to see the separation of two black phases. As additional ether-ethyl acetate extractions were run the task v;as simplified.) The extracts were combined and evaporated to dryness at 6o° C. (15 mm.). The resultant solid was dissolved in 600 ml. ether, (Note: Use of alcohol should be avoided at this point as esters may form), treated with 10 g. of charcoal (Darko-KB), filtered after stirring for 0.5 hour and evaporated to dryness at 50° C. (15 mm.) to yield 46.6 g. of ^2 as a light tan colored acid. This product J2 was found to contain a ratio of approximately 56/44 of product^2/furoic acid. This represented a 63# yield of product ^2.

Purification was accomplished by dissolving the above crude product ^2 in HgO (50 mg./ml.), titrating to pH 2.8 with HCl and extracting with 2 x 200 ml. of 10 ethyl acetate. Evaporation of the-ethyl acetate extracts gave 35# furoic acid and 15# product^. The pH 2.8 aqueous phase was adjusted to pH 0.8 (HCl) and extracted with 2 x 200 ml. ethyl acetate. The organic extracts were combined and washed with 50 ml. HgO. The organic phase was evaporated at 5θ° C. (15 mm.) yielding a solid with a ratio of approximately 86/14 of product ^2/furoic acid. This solid was then recrystallized by dissolving the product 2, In toluene at 50 mg./ml. at 800 C., decanting, and leaving to crystallize at room 20 temperature for 18 hours, yielding 13.3 g. of pure acid 2, by NMR. This represented a 51# yield in the purification and recrystallization step and an overall yield from the 2-furoyl chloride to the pure furyl-2-glyoxylic acid 2 of 16#.

Syn-a-methoxyiminofurylacetic Acid A solution of 4-5 g. of furyl-2-glyoxylic acid 2, in 40 ml. of 50# ethanol was titrated to pH 6 with IN sodium hydroxide and then 3.1 g. of methoxyamine'HCl in 6 ml. of HgO at 20° C. was added. The solution was titrated to a constant pH 4.9 and stirred at pH 4,9 for hours at 20-25° C. The ethanol lias then removed at 50° C. (15 mm.) and the residual aqueous solution was titrated to pH 8 with 50# sodium hydroxide and washed with 3 x 50 ml. ether (pH adjusted to 8 after each wash). The aqueous layer was titrated to pH 1.9 with concentrated HCl and extracted with 5 x 50 ml. ethyl acetate with the pH readjusted to 1.9 after each extraction.· The ethyl acetate extracts were combined and evaporated to a solid at 50° C. (15 mm.). This solid was then slurried-with 75 ml· of Skellysolve B1’. The suspension was filtered and the solids were redissolved in 16 ml, of toluene at 80° C. The hot solution was decanted.and left to crystallize at 20-23° C. for 18 hours to yield 1.17 g.(22# yield of product). The NMR was clean and consistent for the structure 3 with a 4-«/ trace of anti isomer present.

Sodium Syn-a~methoxyiminofurylacetate 4.

To 40 ml. of methanol was added 0.l6 g. of sodium. The mixture was stirred until all of the sodium dissolved and then decanted. The resulting sodium methoxide solution was cooled to 3° C. and 1.12 g. of syn-g-methoxyIminofurylacetic acid^ in 7-8 ml. of methanol vzas added. The solution was stirred for 10 minutes at room temperature. The solvent was evaporated at 40° C. (15 mm.). The residue was dried by azeotropic distillation with 3 x 20 ml, of benzene at 40° C. (15 mm.). The product^ was dried for 18 hours at 23° C. under high vacuum (0.7 mm.) over PgO^ yielding 1.25 g (99# yield of product). The NMR showed this product^ 6 4 31 to be clean and consistent for the structure with 0.15 mole methanol and a trace of anti isomer. 7-(Syn-a-methoxyiminofurylacetamido)-3-(1-carboxymethyltetrazol-5-ylthiomethyl)-3-cephem-4-carboxylic Acid I To 0.63 g. of sodium syn-a-methoxyiminofurylacetate^ suspended in 25 ml. of benzene was added four drops of dry dimethylformamide and Ο.31 ml. (1.1 eq.) of oxalyl chloride. This mixture was stirred for 40 •minutes at 20-23° C. The benzene was removed at 35° C. (15 mm.) and the acid chloride (the gummy residue) was dissolved in 10 ml. acetone (NaCl insolubles were present but not removed). A solution of Ο.98 g. 7-amino-3-(lcarboxymethyltetrazol-5-ylthlomethyl)-3-cephem-4carboxyllc acid in 20 ml, HgO and 0.55 g. of sodium bicarbonate (pH 6.4) was cooled to 3° C. The acetone solution of the above acid chloride was added and the reaction was stirred for 40 minutes at ambient temperature (pH 3 - 4).

The acetone was removed at 30° C. (15 mm.) and the remaining aqueous solution was adjusted to pH 1.8 with 6n HCl. The product^ was extracted with 3 x 60 ml, ethyl acetate. The combined solvent extracts were backwashed with 50 ml. HgO and then evaporated to dryness (with periodic additions of fresh dry ethyl acetate until the water present had been azeotropically removed) at 30° C. (15 mm.) to leave an amorphous solid. This solid residue was triturated with 5θ »1. of ether and collected by filtration yielding 1.02 g.^J (64# yield of product). The NMR was consistent for BL-S1080 with the following contaminations: about 10# anti isomer, about 10# furoic acid, trace dimethylformamide and ether.

Disodium Salt of BL-SI080 · 2.5 Hg0£ 1. To 0.97 S- of J5 (BL-SI080) suspended in ml. HgO was added IN NaOH until a constant pH of 7 was obtained and all of the BL-S1080 had gone into solution. This solution was then lyophilized for 18 hours yielding Ο.93 g. Nag salt of BL-S1080. The NMR of this product Vias consistent for BL-S1080 with about 10# anti10 isomer, about 10# furoic acid and a trace of dimethylformamide. A bioautograph showed just one round spot. 2. Alternative Method for Making Na* Salt of BL-S1080 6 n - ........

Compound J5, (BL-S1080) (0.5 g.) was dissolved 15 in 5 ml. ethanol, filtered, 5 ml. HgO added and titrated to pH 7 with IN NaOH. The ethanol was evaporated at 50° C. (IS mm.) and the remaining solution was lyophilized for 13 hours yielding 0.44 g. Na* salt of BL-S1080. The IR and NMR vrere consistent for BL-S1080 with about 10# 20 anti-isomer and about 10# furoic acid.

Anal. Calc'd for C^gH^NyOgSgNag! C, 38.1; Η, 3·θ1ΐ N, 17.28. Found (corrected for water content): C, 38.28^ H, 3.295 N, 16.41.

Anal. Calc'd for C^H^NyOgSgNag’S.S HgO: KF (HgO), 7.33. Found: KF (HgO), 8.06 There is also provided by the present invention a compound having the formula )¾ R—s -CHg C-OM (θΗ2)η0θ0Η I! o ν wherein R is alkyl containing 1-4 carbon atoms, n is one, two or three and M is HO Mis-C (CH2)nR, -choc(ch2)„c^k3 a1 I ¢,.5 » 6 II 6 -CHXCOR or - CH-S-C-R0 Ii Ii R R n is 0 to 4; R is hydrogen, alkyl having 1 to 8 carbon atoms, cycloalkyl of 3 to 6 carbon atoms, phenyl, 01-0^ phenalkyl, pyridyl, thienyl, or 2 3 propyl; R is hydrogen, methyl or ethyl; R and R are each hydrogen, alkyl having 1 to 6 carbon atoms, phenyl, pyridyl, or thienyl; R and R-' are each £ hydrogen or alkyl of 1 to 4 carbon atoms; R is alkyl having 1 to 4 carbon atoms, phenyl, phenalkyl having 1 to 4 carbon atoms, pyridyl, thiadiazolyl, amino or C1-CZt alkylamino; X is NH or oxygen; and each phenyl •15 group is unsubstituted or substituted with one or two substituents selected from the group consisting of alkyl having 1 to 6 carbon atoms, alkoxy having 1 to 4 carbon atoms, hydroxy, amino, NHr\ N(R^)2, nitro, fluoro, chloro, bromo or carboxy, or a nontoxic, pharmaceutically acceptable salt thereof, said compound being at least 75# by weight in the form of its syn isomer and preferably in the form of its syn isomer essentially free of the corresponding ahtl isomer. 6 4 31 There is also provided by the present invention a compound having the formula fi ii P <0Ac - 0 - hh-ch-ch CH2 N—n · II , .0-N -C-CHo-S-C^^N ^OR1 -c I 3 C-OR^ II o “ -NI (CH2)nC°0H wherein R is alkyl containing 1-4 carbon atoms, n is one, two or three and R Is selected from the group consisting of CH, 0 - CH - 0 - C - R6, δ 6 - CH - C - R , anc CH - X2 - C - OR1 wherein R^ is a hydrogen atom, a methyl or an ethyl group; ‘ 6 X is -0-, -NH-; R is a basic group such as alkyl or aralkyl substituted with substituted or unsubstituted NHg, such' as alkyl-NHCHj, aralkyl-NHCH^, nh2 nh2 R is an alkyl group such as a methyl, ethyl, propyl, Isopropyl, butyl, isobutyl, pentyl or 2-ethyl-hexyl group; a cycloalkyl group such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl or eycloheptyl; an aryl group such as phenyl or naphthyl; an aralkyl group such as benzyl or naphthylmethyl; a heterocyclic group and wherein the alkyl, cycloalkyl, aryl, aralkyl and heterocyclic groups may be substituted with one or more groups selected from the class consisting of amino groups, substituted amino groups such as methylamino, diethylamino or acetamido groups, the halogen groups such as fluorine, chlorine or bromine, nitro groups, alkoxy groups such as methoxy, ethoxy, propyloxy, isopropyloxy, butoxy or isobutoxy; or a nontoxic, pharmaceutically acceptable salt thereof, said compound being at least 75# by weight In the form of its syn isomer and preferably in the form of its syn Isomer essentially free of the corresponding anti isomer. .46431 c7 There is also provided by the present invention a compound having the fonnula ’Ρ H2 V ^C_CH2“S '•KT' wherein R1 is alkyl containing 1-4 carbon atoms, n is one, two or three and M is II C-Y wherein Y is alkyl of one to six carbon atoms, phenyl, benzyl, alkoxy of one to six carbon atoms, or benzyloxy; Z is alkyl of one to six carbon atoms, phenylbenzyl, alkoxy of one to six carbon atoms, cyclopentyl, cyclohexyl and phenyl, or Y+Z taken together are a 3-benzoxazolidine ring; or a nontoxic, pharmaceutically acceptable salt thereof, said compound being at least 75% by weight in the form of its syn isomer and preferably in the form of its syn isomer essentially free of the corresponding anti isomer.

There is further provided by the present invention a pharmaceutical composition comprising an antibacterially effective amount of a compound of formula I and a pharmaceutically acceptable carrier therefor.

There is further provided by the present invention a method of treating bacterial infections, e.g. Haemophilus or Neisseria infections, comprising administering by injection to an infected warm-blooded animal, excluding man, an effective but nontoxic dose of 250-1000 mgm. of a compound of formula I.

Claims (5)

1. A compound having the formula O-c- INH-CH-CH XS ' K CH . .c-ch 2 -s~·» —Κ-ΧΙλ _ \C Z 2 -ΊΓ C-OR' £ (CH 2 ) n COOH wherein R is alkyl containing 1-4 carbon atoms, n is 2 one, two or three and R is pivaloyloxymethyl, acetoxymethyl, methoxymethyl, acetonyl, phenacyl, g-nitrobenzyl, β,β,β - trichloroethyl, 3-phthalidyl or 5-indanyl; or a nontoxic, pharmaceutically acceptable salt thereof, said compound being at least 75% by weight in the form of its syn isomer. OL The syn isomer of a compound having the formula C - C - NH- CH' ll I c~ *OR Ύ >2 Γ ft - N X C ^ C ' CH 2’ S C -N^ iOR (CH,kCOOH 2 n wherein R is alkyl containing 1-4 carbon atoms, n is 2 one, two or three and R is pivaloyloxymethyl, acetoxy15 methyl, methoxymethyl, acetonyl, phenacyl, p-nitrobenzyl, β,β,β-trichloroethyl, 3-phthalidyl or 5-indanyl or a nontoxic, pharmaceutically acceptable salt thereof.

2. X K / COOH ( CH 2)n C 00 H wherein n is one, two or three or a salt, appropriate ester or Schiff base thereof with an organic monocarboxylic 10 acid chloride or a functional equivalent thereof as an acylating agent selected to give a free acid of an ester according to any of Claims 1 to 16 and thereafter converting the free acid to the required ester. 25. A compound of formula I or a non-toxic pharma15 ceutically acceptable salt thereof substantially as described herein. 26. A process for the preparation of a compound of formula I or a non-toxic pharmaceutically acceptable salt thereof substantially as described herein and 20 exemplified. 27. A process according to Claim 17 substantially as described herein. 28. A process according to Claim 24 substantially as described herein. 29. Compounds of formula I when produced by the process of any one of Claims 17 to 24, or 26 to 28. 30. A pharmaceutical composition comprising as an active ingredient a compound according to any one of Claims 1 to 16, 25 to 29 together with a pharmaceutically acceptable carrier or diluent. 31. A pharmaceutical composition according to Claim 30 substantially as described herein. 32. A method of treating bacterial infections comprising administering to a non-human mammal an effective dose of a pharmaceutical composition according to Claim 30 or 31. 33. A method for combatting Haemophilus infections which comprises administering to a warm-blooded nonhuman mammal infected with an Haemophilus infection an amount effective for treating said Haemophilus infection of a composition comprising a compound according to Claim 1 and a pharmaceutically acceptable carrier therefor. 34. A method for combatting Neisseria infections which comprises administering to a warm-blooded, nonhuman mammal infected with a Neisseria infection an amount effective for treating said Neisseria infection of a composition comprising a compound according to Claim 1 and a pharmaceutically acceptable carrier therefor. 35. A method according to Claim 33 or 34, wherein the said compound is in the form of its syn isomer

3. A compound of any one of Claims 1 or 2, wherein n is one. 4. 6.4 31 16. The syn isomer of a compound according to any one of Claims 6 to 15. 17. A process for the preparation of an ester according to any one of claims 1 to 16 of a compound of 5 the formula NH - CHzS\ •CH CH ,, ft N. x C z I C - OH Cii„ N-N I! ll ia S_c I (CH 2 ) n C00H wherein R 1 is alkyl containing 1 to 4 carbon atoms and n is one, two or three, or a non-toxic pharmaceutically acceptable salt of said ester characterized by reacting a compound of the formula in which Y is H or wherein R 1 is as defined above or a salt or appropriate 15 ester thereof with a compound of the formula N-ft HS_S N (CH 2 ) n COOH in which n is one, tvzo or three and when ϊ is H treating the resulting compound with.an acylating agent of the formula in which X is halide or a functional equivalent thereof and is as defined above, and if appropriate converting a resulting free acid of the formula Ia to a corresponding ester or non-toxic pharmaceutically acceptable salt thereof. 18. The process according to Claim 17, wherein a resulting free acid of the formula Ia is converted to an ester selected from pivaloyloxymethyl-, acetoxymethyl-, methoxymethyl-, acetonyl-, phenacyl-, ρ-nitrobenzyl-, β-β-βtrichloroethyl-, 3-phthalidyl-.and 5-indanyl-oxy esters. 19. The process according to Claim 17 or 18 wherein ρΛ is methyl or ethyl. 20. The process according to any of Claims 17 to 19, wherein n is one. 21. The process according to any of Claims 17 to 19, wherein n is two. 22. The process according to any of Claims 17 to 19, wherein n is three. 23. The process according to any of Claims 17 to 22 wherein the compound of formula I is in the form of the syn isomer. 24. A process for the preparation of a compound according to any of Claims 1 to 16 which comprises reacting a compound of the formula H -CH—CK' 6 i ! ,/ S \, 'CK, ,C-N CHi- S — C K 4 5 phenyl, pyridyl, or thienyl; R and R are each hydrogen or alkyl of 1 to 4 carbon atoms; R 5 is alkyl having 1 to 4 5 carbon atoms, phenyl, phenalkyl having 1 to 4 carbon atoms, pyridyl, thiadiazolyl, amino or C^-C^ alkylamino; X is NH or oxygen; and each phenyl group is unsubstituted or substituted with one or two substituents selected from the group consisting of alkyl having 1 to 6 carbon atoms, alkoxy having 1 to 4 10 carbon atoms, hydroxy, amino, ΝΗΠ 1 , N(R 1 ) 2 , nitro, fluoro, chloro, bromo or carboxy, or a nontoxic, pharmaceutically acceptable salt thereof, said compound being at least 75% by weight in the form of its syn isomer. 7. A compound having the formula NH—CH /x 7 S H 2 ,>3~ CH 2 Ϊ . (CH 2 ) n COOH •0R“ wherein R 1 is alkyl 3 two or three and R containing 1 to 4 carbon atoms, n is one, is selected from the group consisting of CH, 0 C,H r 0 R 5 O I II I 5 li fi fi ? 7 -CH-O- C-R° —CH—— C-R —CH-X —C-0R z J wherein R is a hydrogen atom, a methyl or an ethyl group; X 2 is -0-, -NH-; fi 7 R is a basic group; R is an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or a heterocyclic group and wherein the alkyl, cycloalkyl, aryl, aralkyl and heterocyclic groups may be substituted with one or 5 more groups selected from amino groups, substituted amino groups, halogen groups, nitro groups, and alkoxy groups, or a nontoxic, pharmaceutically acceptable salt thereof, said compound being at least 75% by weight in the form of its syn isomer. 10 8. A compound or salt according to Claim 6, wherein R® is alkyl or aralkyl substituted with substituted or unsubstituted NH 2 . 9. A compound or salt according to Claim 8, wherein R° is an alkyl or aralkyl group substituted with alkyl-NHCH^, 15 aralkyl-NHCHg, aralkvl-NH-^O^ 1 alkyl-NH -CH , -ΟΗ,ΝΗ,,ογ -CH-CH 2 -^^ nh 2 nh 2 10. A compound or salt according to Claim 7, 8, 9, wherein R is a substituted or unsubstituted alkyl group selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, 20 pentyl and 2-ethyl-hexyl. 11. A compound or salt according to Claim 7, 8, 9, wherein R is a substituted or unsubstituted cycloalkyl group selected from cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and cycloheptyl. 25 12. A compound or salt according to Claim 7, 89, wherein R is a substituted or unsubstituted aryl group selected from phenyl and naphthyl. <6431 ό2 13. A compound or salt according to Claim 7, 8 or 9, wherein R is a substituted or unsubstituted aralkyl group selected from benzyl and naphthyl methyl. 14. A compound or salt according to any one of Claims 5 7 to 13, wherein R is substituted with one or more groups selected from amino, methylamino, diethylamino,acetamido, fluorine, chlorine, bromine, nitro, methoxy, ethoxy, propyloxy, isopropyloxy, butoxy and isobutoxy. 15. A compound having the formula -NH—CH \ 7 OR 0M (CH_) COOH ζ n wherein R 1 is alkyl containing 1 to 4 carbon atoms, n is one, two or three and M is C-Y / -CH--N 2 \ z wherein Y is alkyl of one to six carbon atoms, phenyl, benzyl, 15 alkoxy of one to six carbon atoms, or benzyloxy; Z is alkyl of one to six carbon atoms, phenylbenzyl, alkoxy of one to six carbon atoms, cyclopentyl, cyclohexyl and phenyl or Y+Z taken together are a 3-benzoxazolidine ring; or a nontoxic pharmaceutically acceptable salt thereof, said compound being at least 75% by weight in the form of its syn isomer. ·'/

4. A compound of any one of Claims 1 or 2, wherein n is two. 5. A compound of any one of Claims 1 or 2, wherein n is three. 5 6. A compound having the formula C—OM (CH^COCH 0 7 wherein R is alkyl containing 1 to 4 carbon atoms, n is one, two or three and M is 0 0 R 2 0 0 « i / ii 6 1 6 -CHOC (CH-,) R, -C11OC(CH„) C , -CHXCOR U or -CH-S-C-R I I |V I I II 1 1 1 4 5 1 1 R x R x NR R R R 10 n is 0 to 4; R is hydrogen, alkyl having 1 to 8 carbon atans, cycloalkyl of 3 to 6 carbon atoms, phenyl, C^-C^ phenylalkyl, .χ 4 6 4 31 pyridyl, thienyl, or propyl; is hydrogen, methyl or ethyl; 2 3 R and R are each hydrogen, alkyl having 1 to 6 carbon atoms,

5. Essentially free of the corresponding anti isomer.