7-Trifluorome thylsulfinylacetamido cephalosporins
United States Patent De Marinis et a1.  
 7-TRIFLUOROME THYLSULFINYLACETAMIDO C EPHALOSPORINS lnventorsi Robert M. De Marinis, King of Prussia; John R. E. Hoover, Glenside, both of Pa.  
 SmithKline Corporation, Philadelphia, Pa.  
 Filed: June 18, 1973 Appl. No.: 371,081  
 Assignee:  
 US. Cl. 260/243 C; 424/246 Int. Cl C07d 99/24 Field of Search 260/243 C References Cited UNITED STATES PATENTS 1/1967 Flynn 260/243 C Primary Examiner-Nicholas S, Rizzo Attorney, Agent, or FirmA1an D. Lourie; William H. Edgerton [57] ABSTRACT Cephalosporin compounds having a trifluoromethylsulfinylacetamido group at the 7-position and various groups at the 3-position are prepared by acylation of a 7-aminocephalosporanic acid. The compounds have anti-bacterial activity.  
 5 Claims, No Drawings 7-TRIFLUOROME THYLSULFINYLACETAMIDO CEPHALOSPORINS This invention relates to cephalosporin compounds which have antibacterial activity. In particular, the invention relates to compounds having a trifluoromethylsulfinylacetamido substituent at position 7 of the cephem nucleus.  
  The compounds of this invention are represented by the following structural formula:  
 CF CH2CONH in which:  
 M is hydrogen or an alkali metal or ammonium cation;  
 A is hydrogen, methyl, acetoxymethyl, pyridiniummethyl, CH SHet, CH SR&#39; or CH OR&#39;, where R is hydrogen or alkyl of from one to four carbon atoms; and  
 Het is a five or six membered heterocyclic group containing carbon and one to four atoms selected from the group consisting of N, O and S, each such group being unsubstituted or substituted with from one to two groups selected from lower alkyl, alkoxyalkyl, and trifluorometliyl, each alkyl or alkoxy group having from one to four carbon atoms, or an N-oxide thereof.  
  Preferred compounds are those where A is acetoxymethyl or CH SHet. Particularly preferred as those compounds where Het is unsubstituted or methyl substituted 1,2,3-triazolyl, 1,2,4-triazolyl, l,2,3,4- tetrazolyl, oxazolyl, thiazolyl, 1,3,4-oxadiazolyl, 1,3,4- thiadiazolyl, or 1,2,4-thiadiazolyl.  
  Included within the scope of this invention are the pharmaceutically acceptable salts that are formed by reaction of the cephalosporanic acid with a pharmaceutically acceptable base.  
  Cephalosporins with a wide variety of acyl groups at position 7 of the cephem nucleus have been disclosed in the prior art, including many 7- alkylmercaptoacetamidocephalosporanic acid derivatives (US. Pat. Nos. 3,573,298, 3,297,692 and others). 7-Substituted alkylsulfinylacetamidocephalosporanic acids variously substituted at position 3 (but not with CH SHet) are described in US. Pat. No. 3,382,238 and German Pat. No. 2,000,878. Our own copending application Ser. No. 273,571, filed July 20, 1972, now US. Pat. No. 3,828,037 discloses 7-trifluoromethylmercaptoacetamidocephalosporins. However, no cephalosporins with a trifluoromethylsulfinyl group in the 7-acyl substituent are known.  
  The compounds of this invention are prepared by acylation of the appropriately substituted 7-aminocephalosporanic acid with trifluoromethylsulfinylacetic acid. The carboxyl group of the acylating agent may be activated by one of the methods known in the art such as the mixed anhydride. acid halide, or activated ester. 1n additioin, acylation of esters of the cephalosporin nucleus may be done by use of a coupling reagent such as dicyclohexylcarbodiimide.  
  Following the acylation, the protective groups can be removed with an acid such as trifluoroacetic acid.  
  The compounds are also prepared by displacement of a 7-acylated .3-acetoxymethylcephalosporin with a mercaptoheterocycle in an aqueous, slightly basic medium.  
  Trifluoromethylsulfinylacetic acid is prepared by hydrogen peroxide oxidation of trifluoromethylmercaptoacetic acid according to known procedures [Zh. Obshch. Khim. 35, 9, 1628 (1965)].  
  The compounds of this invention have antibacterial activity against both Gram-positive and Gram-negative organisms. Minimum inhibitory concentrations (MICs) ranged from 0.1 to 200 ug/ml in in vitro testing. These results are shown below for 7- trifluoromethylsulfinylacetamido-3-acetoxymethyl-3- cephem-4-carboxylic acid (1) and 7- trifluoromethylsulfinylacetamido-3-( l-methyl-l ,2 ,3 ,4- tetrazol-S-ylthiomethyl)-3-cephem-4-carboxylic acid (11). When administered in vivo (s.c.), compound 1 showed an ED of 29 mg/kg against E. coli and 200 mg/kg against Klebs. pneumo. The ED for compound 11 against e. coil was 4.6-22 mg/kg; against Klebs. pneumo. it was 50-56 mg/kg.  
 TABLE 1 MlC (#g/ml) Bacteria l 11 S. aureus HH 127 1.6 0.8 S. aureux SK 23390 1.6 0.8 Strep. pyog. C203 0.2 0.1 Strep. faecalis HH 34358 100 100 E. coli SK 12140 6.3 0.8 E. coli HH 33779 12.5 1.6 K1017. pneumo. SK 4200 3.1 0.8 Kleb. pneumo. SK 1200 3.1 0.8 Pst&#39;udomonas sp. HH 63 200 200 Salmonella 3.1 0.4 Shigella 6.3 0.4 Emeru. aerogenes 50 1.6 Serralia mare. ATCC 13880 200 200 S. villaluz SK 70390 100 50 Enrero. cloaca HH 31254 12.5  
  These compounds are formulated and administered by injection in doses of 250-500 mg in the same manner as other cephalosporins. The precise dosages are dependent upon the age and weight of the subject and on the nature of the infection being treated. Determination of dosages is within the skill of the art.  
  The following examples illustrate the invention, but are not to be construed as limiting the scope thereof. Temperatures are in degrees Centigrade unless otherwise stated.  
 EXAMPLE 1 7-Trifluoromethylsulfinylacetamido-3-acetoxymethyl- 3-cephem-4-carboxylic acid trifluoromethylsulfinylacetamido-3-acetoxymethyl-3- cephem-4-carboxy1ic acid as a gum which was then dissolved in 50 ml of ethyl acetate. The solution was filtered and to the filtrate was added with stirring 1.5 ml of a 30% solution of sodium 2-ethylhexarioate in isopropanol. Dropwise addition of the resultant solution to 200 ml of pet ether caused precipitation of the sodium salt (0.515 g, 73%) which was collected and purified by solution in 5 ml of acetonitrile and addition of this solution to 100 ml of rapidly stirred ether. The preciptate was collected, washed with ether and dried in vacuo to give 0.370 g of pure salt.  
 C H F N O,S .Na.1 H O.1 CF CO H (584.424)  
 7-Amino-3-( l-methyl- 1 ,2,3 ,4-tetrazol-5-ylthiomethyl)- 3-cephem-4-carboxylic acid To a suspension of 27.2 g (0.1 mol) of 7-ACA in 200 ml of water and 100 ml of acetone was added a solution of 18.9 g of sodium bicarbonate in 200 ml of water. The resultant solution was warmed on a steam bath and a solution of 14.5 g (0.125 mol) of l-methyl-S-mercaptol,2,3,4-tetrazole in 200 ml of acetone was added. The reaction mixture was refluxed for 3.5 hr. while maintaining the pH at 7.48.0 by addition of 5% sodium bicarbonate. Acidification of the cooled reaction mixture to pH 3.5 with 6N hydrochloric acid resulted in precipitation of 7-amino-3-( l-methyll ,2,3,4-tetrazol-5- ylthiomethyl)-3-cephem-4-carboxylic acid, which was collected, washed with water and air dried (16 g, 49%).  
 EXAMPLE 3 7-Trifluoromethylsulfiny1acetamido-3-( l-methyl- 1 ,2,3 ,4-tetrazol-5ylthiomethyl )-3-cephem-4- carboxylic acid To a solution of 1.54 g (0.004 mol) of 7-amino-3-(1- methyl-1 ,2,3,4-tetrazol-5-ylthiomethyl )-3-cephem-4- carboxylic acid; t-butyl ester and 0.825 g (0.004 mol) of dicyclohexylcarbodiimide in 50 ml of benzene was added 0.704 g (0.004 mol) of trifluoromethylsulfinylacetic acid. The reaction mixture was stirred at 25 for 2 hr., then it was filtered and adsorbed onto 4 g of silica gel. Chromatography on 100 g of silica gel with 50:50 benzene-ethyl acetate gave 1.55 g (69%) of 7- trifluoromethylsulfinylacetamido-3-( l-methyl-l ,2,3,4- tetrazol-S-ylthiomethyl)-3-cephem-4-carboxylic acid, t-butyl ester as a white foam. The ester was dissolved in 9 m1 of trifluoroacetic acid and stirred at 25 for 5 minutes, then added dropwise to 200 ml of ether. The precipitate was collected, dissolved in 5% sodium bicarbonate and the solution was diluted to 150 ml. After extraction with ethyl acetate the aqueous phase was acidified to pH 1.5 and extracted thrice more with ethyl acetate. The combined extracts were dried (MgSO and concentrated to 35 ml, to whichre s&#39;idue (the free acid) was added a solution of 1.5 oF30% sodium 2- ethylhexanoate i n isopropanol followed&#34;by 200 ml of :1  
 ether. The precipitated salt was collected, re-  
 precipitated from methanol-ether and dried in vacuo to give 0.680 g of product.  
 C H F N O S .Na. /2 H O (517.484)  
  7-Trifluoromethylsulfinylacetamido-3-( l ,3,4- thiadiazol-2-ylthiomethyl)-3-cephem-4-carboxylic acid To a solution of 3.1 g (0.009 mol) of 7-amino-3- l,3,4-thiadiazol-2-ylthiomethyl)-3-cephem-4- carboxylic acid in ml of 3% aqueous sodium bicarbonate is added 60 ml of acetone. The solution is cooled to -l5 and 1.94 g (0.010 mol) of trifluoromethylsulfinylacetyl chloride in 20 ml of acetone is added over a 10-minute period. The reaction mixture is stirred at -l5 for 30 minutes while maintaining the pH at 7.6-8.0 by addition of 10% sodium hydroxide, then at 25 for 1 hour. The reaction mixture is extracted once with ether and the aqueous phase is acidified to pH 2.5 with dilute hydrochloric acid and extracted with ethyl acetate. The organic extracts are dried (MgSO and concentrated in vacuo to give the title compound.  
 EXAMPLE 5 When either an equivalent amount of a 7-amino-3- heterocyclicthiomethyl-3-cephem-4-carboxylic acid (prepared by the procedure of Example 2) listed below is substituted into the procedure of Example 4 for 7- amino-3-( l,3,4-thiadiazol-2-ylthiomethyl )-3-cephem- 4-carboxy1ic acid or its t-butyl ester is substituted into the procedure of Example 3 for 7-amino-3-(1-methyl- 1 ,2,3 ,4-tetrazol-5ylthiomethyl )-3-cephem-4- carboxylic acid, t-butyl ester, the appropriate 7- trifluoromethylsulfinylacetamido-3- heterocyclicthiomethyl-3-cephem-4-carboxylic acid is obtained.  
 7-amino-3-(5-methy1-1,3 ,4-thiadiazo1-2- ylthiomethyl)-3-cephem-4-carboxylic acid 7-amino-3-( 5&#39;-ethyl- 1 ,3 ,4-thiadiazol-2-ylthiomethyl 3-cephem-4-carboxylic acid 7-amino-3-(S-trifluoromethyl-l ,3,4-thiadiazol-2- ylthiomethyl)-3-cephem-4-carboxylic acid 7-amino-3-( S-n-butyl-l ,3 ,4-thiadiazol-2- ylthiomethyl)-3-cephem-4-carboxylic acid 7-amino-3-( 1 ,2,4-thiadiazol-5ylthiomethyl )-3- cephem-4-carboxylic acid 7-amino-3-(3-methyl-1 ,2,4-thiadiazol-5- ylthiomethyl)-3-cephem-4-carboxy1ic acid 7-amino-3-( 3-ethyl-l ,2,4-thiadiazol-5ylthiomethyl 3-cephem-4-carboxylic acid 7-amino-3-(thiazol-5-y1thiomethyl)-3-cephem-4- carboxylic acid 7-amino-3-( 2-methy1thiazol-5-ylthiomethyl )-3- cephem-4-carboxylic acid 7-amino-3-(4-methylthiazol-S-ylthiomethyl)-3- cephem-4-carboxylic acid 7-amino-3-(2,4-dimethylthiazol-5ylthiomethyl)-3- cephem-4-carboxylic acid ,7-amino-3-( 2-ethylthiazol-5ylthiomethyl )-3- cephem-4-carboxy1ic acid cording to the procedure of Example 1 gives the title compound.  
 EXAMPLE l 7-Trifluoromethylsulfinylacetamido- 3-cephem-4- carboxylic acid A solution of 0.78 g (2 mmol) of benzhydryl 7- amino-3-cephem-4-carboxylate (South African Pat. No. 71/067 19), 0.35 g (2 mmol) of trifluoromethylsulfinylacetic acid and 0.4 g (2 mmol) of dicyclohexylcarbodiimide in dry tetrahydrofuran (15 ml) is stirred at room temperature overnight. The precipitate is collected and washed with tetrahydrofuran and the combined filtrate and washings are evaporated in vacuo. The residue is treated with a cold solution of trifluoroacetic acid (10 ml) and anisole (0.5 g) for minutes and then concentrated in vacuo. The residue is dissolved in ethyl acetate and treated with 5% aqueous sodium bicarbonate. The aqueous phase is adjusted to pH 2 and the precipitated product is collected and dried.  
 EXAMPLE 1 l An injectable pharmaceutical composition is formed by adding sterile water or sterile saline solution (2 ml) to 500 mg of 7-trifluoromethylsulfinylacetamido-3-( lmethyl-l ,2,3 ,4-tetrazol-5-ylthiomethyl)-3-cephem-4- carboxylic acid, sodium slt.  
  Pharmaceutical compositions of the other antibacterial compounds described by Formula I or disclosed in the above examples may be formulated in a similar manner.  
 We claim:  
 1. A compound of the formula:  
 COOM  
 in which:  
 M is hydrogen or an alkali metal or ammonium cation;  
 A is CH Sl-let; and  
 Het is a five or six membered heterocyclic group containing carbon and one to four atoms selected from the group consisting of N, O and S, each such group being unsubstituted or substituted with from one to two groups selected from lower alkyl, alkoxyalkyl, and trifluoromethyl, each alkyl or alkoxy having from one to four carbon atoms, or an N- oxide thereof.  
  2. A compound as claimed in claim 1 where Het is triazolyl, tetrazolyl, oxazolyl, thiazolyl, or thiadiazolyl, each Het group being unsubstituted or substituted with one or two alkyl groups of from one to four carbon atoms.  
  3. A compound as claimed in claim 2, being the compound 7-trifluoromethylsulfinylacetamido-3-( lmethyl-l ,2,3,4-tetrazol-5-ylthiomethyl)-3-cephem-4- carboxylic acid.  
  4. A compound as claimed in claim 2, being the compound 7-trifluoromethylsulfinylacetamido-3-( 5- methyl-1 ,3 ,4-thiadiazol-2-ylthiomethyl )-3-cephem-4- carboxylic acid.  
  5. A compound as claimed in claim 2, being the compound 7-trifluoromethylsulfinylacetamido-3-( 1,2,3-  
 triazol-4-ylthiomethyl)-3-cephem-4-carboxylic acid.