GB1599469A

GB1599469A - Antibiotics of the group of cephalosporins

Info

Publication number: GB1599469A
Application number: GB1592578A
Authority: GB
Original assignee: Laboratorios Cusi SA
Current assignee: Alcon Cusi SA
Priority date: 1978-04-21
Filing date: 1978-04-21
Publication date: 1981-10-07

Description

(54) ANTIBIOTICS OF THE GROUP OF CEPHALOSPORINS (71) We, LABORATORIOS CUSI, S.A., a Spanish Body Corporate, of Masnou, Barcelona, Spain. do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to antibiotics of the group of Cephalosporins.

The present invention provides compounds of the formula:

wherein R = H or an alkyl group, M = H, an alkali metal, NH4, or an alkaline earth metal, X = H, an alkyl group. a halogen or hydroxyl, Z = H or a methoxy group.

The above-mentioned compounds can be obtained in various ways.

A) Starting from 7-ACA (a) By reacting 7-ACA with 1,3,4-thiadiazol-5-alkyl-2-mercaptoacetic acids in any of their reactive forms, compounds II are obtained which, when subjected to reaction with (4,5-b)pyridazin-6-thiol-X-substituted tetrazole, give compounds I

(b) By reacting 7-ACA with the mentioned thiols, compounds III are obtained which with the reactive form of the mercaptoacetic acids give compounds I

(c) The 7-ACA can be reacted with a haloacetic halide giving compounds IV which with l.3,4-thiadiazol-5-alkyl-2-thiol give compounds II, which are converted into compounds I in the same way as in paragraph A, (a).

(d) Starting from compounds 111 and reacting firstly with haloacetyl halide to give compounds V which. when reacted with I ,3,4-thiadiazol-5-alkyl-2-thiol. give compounds l

B) Starting from an ester of 7-ACA which is readily hydrolizable, for example tert-butyl, 2,2,2-trichloroethyl, pivaloyloxymethyl esters (e) By reacting the tert-butyl ester of 7-ACA with 1,3,4-thiadiazol-5-alkyl-2- mercaptoacetic acids, either as such - with the help of a condensing agent such as dicvclohexvlcarbodiimide - or in their reactive forms. The compound VI obtained is subjected to reaction with (4.5-b)-pyridazin-6-thiol-X-substituted tetrazole, and the tert-butyl ester of compound I thus obtained is reacted with trifluoroacetic acid:anisole (9:1) to give compound I

Ri$l% H 7ACA(tBulesterA-zsÒH PACA(t-Bvlester Ac O ktH20Ac E C02CMe3

(f) By reacting the tert-butyl ester of 7-ACA with (4,5-b)pyridazin-6-thiol-Xsubstituted tetrazole, compound VIII is obtained which, when reacted with 1,3,4thiadiazol-5-alkyl-2-mercaptoacetic acids, gives compounds VII

N11 S SCH2CO2H ~ Vlll (g) By reacting the tert-butyl ester of 7-ACA with a haloacetyl halide, compounds IX are obtained which, when reacted with 1,3,4-thiadiazol-5-alkyl-2-thiol, give compounds VI.

The conversion of compound VI to compound I is verified as in paragraph B, (e)

(h) If the tert-butyl ester of 7-ACA is reacted with (4,5-b)pyridazin-6-thiol-Xsubstituted tetrazole, compounds VIII are obtained. The reaction of compounds VIII with a haloacetyl halide gives compounds X which with l,3,4-thiadiazol-5-alkyl-2-thiol gives compounds VII

The compounds of the present invention can be converted into non-toxic pharmaceutically acceptable salts by the reaction with an alkali metal hydroxide, an alkali metal bicarbonate or carbonate or an organic base. The preferred method for preparing these salts consists in dissolving the free acid in a solvent in which the salt is insoluble and adding the basic component. The compounds of the present invention have a good bactericidal activity, inhibiting the growth of a good number of micro-organisms, including grampositive and gram-negative bacteria.

For therapeutic administration, the compounds of the present invention can be used in different pharmaceutical forms, with the help of various excipients, both organic and inorganic, whether for oral or parenteral administration. The pharmaceutical preparations can be in a solid form, for example, capsules, tablets or pills, or in a liquid form such as solutions, suspensions or emulsions. If desired, they can contain auxiliary substances, such as stabilizers, emulsifiers, buffers or other additives normally used.

The dose of these compounds varies with age and the degree of infection which the patients suffer. Doses of 100, 250 and 500 mg. of the compounds of the present invention have proved effective in the treatment of disorders produced by bacterial infections.

The invention will be further described with reference to the following illustrative Examples.

By way of example, there is described the preparation of 7-(1,3,4-thiadiazol-5-methyl-2 mercaptoacetamide)-3-tetrazol-(4,5-b)pyrridazin-6-yl-thiomethyl-3-cefem-4-carboxylic acid using the various methods previously outlined.

Example I To a 500 cc. flask provided with a thermometer, a stirrer and an addition funnel were added 3.524 g of 1,3 ,4-thiadiazol-5-methyl-2-mercaptoacetic acid, 50 cc of dichloromethane and 3 cc of triethylamine. The resulting solution was cooled to OOC and, maintaining the temperature, 2.4 g of pivaloyl chloride dissolved in 20 cc of dichloromethane were added.

After completion of the addition, the solution was stirred for 1 hour in an ice bath. Another solution consisting of 5.6 g of 90% 7-ACA, 150 of dichloromethane and 7 cc of triethylamine was added slowly to the previoulsy mentioned solution. The reaction was continued for 20 hours allowing the same to reach room temperature. The reaction mixture was evaporated to dryness and the residue was divided between 200 cc of ethyl acetate and 300 cc of 0.1N phosphate buffer solution at a pH of 7.5. The organic layer was separated and the aqueous layer was acidulated at a pH of 2 and was extracted with ethyl acetate (5 per 200). The extracts were washed with brine, dried, discoloured and evaporated. A semi-solid solution was produced which was triturated with two 25 cc portions of ether, followed by filtration and drying, providing 4.2 g of compound II (R=Me).

To a 500 cc flask were added 8.88 g of compound II, 3.06 g of tetrazol (4,5-b)pyridazine6-thiol, 3.36 g of sodium bicarbonate, 100 cc of 0.1N phosphate buffer solution at a pH of 6.4 and 100 cc of acetone. The mixture was heated to 80"C for 2.5 hours. The mixture was cooled in an ice bath and precipitated with 2N HCI to a pH of 2, and subsequently filtered, washed and dried, providing 6.8 g of compound I (R=Me, M=H, X=H) having a melting point of 150-154"C (desc.). IR (KBr) 3,300, 1,780, 1,680, 1,540 cm Example 2 To a 1,000 cc flask were added 6.72 g of tetrazol (4,5-b)pyridazin-6-thiol, 12 g of 7-ACA, 7.4 g of sodium bicarbonate and 400 cc of 0.1N phosphate buffer solution at a pH of 6.5.

The resulting suspension was heated slowly to 80"C for 2.5 hours, and was allowed to dry slowly whereby a solid was produced. At room temperature acidulation to a pH of 3 was effected. Cooling to 0 C for 1 hour, filtering and drying were also effected, providing 9.6 g of compound III (X=H).

To a 100 cc flask which contained 0.01 mol of mixed anhydride of 1,3,4-thiadiazol-5methyl-2-mercapto-acetic and pivalic acids, were added, in portions, 3.65 g of compound III previously obtained. The reaction mixture was allowed to react for 20 hours whereafter preparation took place by normal techniques, providing 1.2 g of a product identical to that product obtained in Example 1.

Example 3 To a 250 cc flask were added 5.44 g of 7-ACA, 150 cc of dichloromethane, and 5 cc of triethylamine. The solution was cooled to "C and 4.05 g of bromoacetyl bromide in 20 cc of dichloromethane were added. The reaction mixture was allowed to stand until the following day. The mixture was evaporated to dryness and the residue was dissolved in 200 cc of 2% sodium bicarbonate, followed by washing with 50 cc of ethyl acetate. The aqueous solution was acidulated at a pH of 2 with 2N HCl and extracted with ethyl acetate (3 per 100). The extracts were washed with brine, dried and evaporated. The residue was dissolved in 100 cc of dichloromethane and 3 cc of triethylamine and 2.6 g of 1,3,4-thiadiazol-5-methyl-2-thiol were added thereto, followed by stirring for 3-4 hours at room temperature and evaporation to dryness. The residue was dissolved in 200 cc of a phosphate buffer solution at a pH of 7.5, followed by washing with 50 cc of ethyl acetate, and the aqueous solution was acidulated at a pH of 2 and extracted with 300 cc of ethyl acetate. The washed and dried extracts were discoloured and evaporated to dryness, providing 3 g of compound II. The conversion of compound II to compound I was verified under identical conditions as in Example 1.

Example 4 In 50 cc of dichloromethane were suspended 3.65 g of compound III and 3 cc of triethylamine were added thereto. The solution was cooled in an ice bath and 2.02 g of bromoacetyl bromide in 20 ml of dichloromethane were added thereto dropwise. The reaction was allowed to stand until the following day. Then 1.5 cc of triethylamine and 1.32 g of 1,3,4-thiadiazol-5-methyl-2-thiol were added and stirring took place for 4 hours at room temperature. The reaction product was evaporated to dryness and dissolved in 100 cc of 4% sodium bicarbonate. The normal procedure was followed, providing 1.6 g of compound I.

Example 5 To a 100 cc flask were added 3.38 g of tert-butyl ester of 7-ACA, 2.06 g of dicyclohexylcarbodiimide, 1.9 g of 1,3 ,4-thiadiazol-5-methyl-2-mercaptoacetic acid and the mixture was stirred in the presence of 80 cc of dichloromethane for 24 hours, followed by filtration and evaporation of the filtrate to dryness. The filtrate was suspended in 50 cc of 0.1N phosphate buffer solution at a pH of 6.8 and 5 cc of acetone, 840 mg of sodium bicarbonate and 1.53 g of tetrazol (4,5-b)pyrridazin-6-thiol were added. The mixture was heated slowly for 4 hours to 60"C, cooled and extracted with ethyl acetate (3 per 100). The extracts were washed with bicarbonate, water, hydrochloride, water and brine, and were dried, discoloured and evaporated to dryness. The residue (VII) was dissolved in 20 cc of trifluoroacetic acid and 2 cc of anisole and was cooled to 0 c. Stirring was maintained at this temperature for 1 hour and at 200C for 10 minutes, followed by evaporation to dryness, 20 cc of dichloromethane were added and evaporation was repeated. The residue was dissolved in 50 cc of 4% bicarbonate, washed with ethyl acetate, and acidulated at a pH of 2, and the precipitate was filtered, dried and weighed providing 1.2g of compound I.

Example 6 To a 100 cc flask were added 3.38 g of terbutyl ester of 7-ACA, 50 cc of phosphate buffer solution at a pH of 6.8, 5 cc of acetone, 840 mg of bicarbonate and 1.53 g of tetrazol (4,5-b)pyrridazin-6-thiol. The mixture was heated to 600C for 4 hours, cooled and extracted with ethyl acetate (3 per 100), washed with bicarbonate and water, dried and evaporated to dryness, providing 3.5 g of compound VIII.

4.21 g of compound VIII were added to a solution of mixed anhydride of 1,3,4-thiadiazol5-methyl-2-mercaptoacetic acid and pivalic acid, obtained as set forth in Example 1, in 50 cc of methylene chloride and 3 cc of triethylamine. The mixture was stirred for 20 hours and preparation took place by the normal procedure, providing 4.4. g of compound VII which were converted into 3.2 g of compound I as in Example 5.

Example 7 To 0.01 mol of tert-butyl ester of 7-ACA dissolved in 100 cc of dichloromethane were added 1 cc ot triethylamine and 2.03 g of bromoacetyl bromide in 15 cc of dichloromethane.

The addition took place at OOC and thereafter the reaction was contained for 3 hours at room temperature. The reaction product was evaporated to dryness and treated as in the previous examples, providing 3.4 g of crude compound IX which were dissolved in 50 cc of dichloromethane and 1 cc of triethylamine and 1.2 g of 1,3,4-thiadiazol-5-methyl-2-thiol were added thereto. The mixture was stirred for 4 hours at room temperature, and treated as in the previous examples, providing 3.7 g of compound VI identical to that obtained in Example 5. The obtention of compound 1 from compound VI is set out in Example 5.

Example 8 To 0.01 mol of VIII dissolved in 50 cc of dichloromethane was added 1 cc of triethylamine and the solution was cooled to 0 c. Thereafter Q.01 mol of bromo acetyl bromide was added slowly dropwise in 10 cc of dichloromethane. Following the normal treatment 3.8 g of compound X were obtained, which were dissolved in 50 cc of dichloromethane to which were added 1 cc of triethylamine and 0.9 g of 1,3,4-thiadiazol-5-methyl-2-thiol. The mixture was reacted for 4 hours at room temperature providing, after the normal treatment, 4 g of compound I.

Compound I (R=Me, M=H, X=H) has the following minimum inhibiting concentrations (in y/ml) as contrasted with the following list of bacteria: SARCINA LUTEA 60.19 STAPHYLOCOCCUS AUREUS 60.19 ESCHERICHIA COLI 6.25 KLEBSIELLA PNEUMONIAE 1.56 PROTEUS VULGARIS 3.12 PSEUDOMONAS AERUGINOSA > 100 ALCALIGENES FAECALIS 12.5 STAPHYLOCOCCUS EPIDERMIDIS 0.19 BORDETELLA BRONCHISEPTICA 50 MICROCOCCUS FLAVUS 0.39 ENTEROBACTER LIQUEFACIENS 100 STREPTOCOCCUS f. LANCEFIELD 50 CANDIDA ALBICANS > 100 BACILLUS SUBTILIS 60.19 BACILLUS PUMILUS 0.19 SALMONELLA PARATYPHI 3.12 SALMONELLA TYPHI 1.56 SACCHAROMYCES CEREVISIAE 25 WHAT WE CLAIM IS: 1. Compounds of the formula

wherein R = H or an alkyl group, M = H, an alkali metal, NH4, or an alkaline earth metal, X = H. an alkyl group. a halogen or hydroxyl, Z = H or a methoxy group.

2. Compounds according to Claim 1, in the form of non-toxic pharmaceutically acceptable salts.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

Example 8 To 0.01 mol of VIII dissolved in 50 cc of dichloromethane was added 1 cc of triethylamine and the solution was cooled to 0 c. Thereafter Q.01 mol of bromo acetyl bromide was added slowly dropwise in 10 cc of dichloromethane. Following the normal treatment 3.8 g of compound X were obtained, which were dissolved in 50 cc of dichloromethane to which were added 1 cc of triethylamine and 0.9 g of 1,3,4-thiadiazol-5-methyl-2-thiol. The mixture was reacted for 4 hours at room temperature providing, after the normal treatment, 4 g of compound I.

Compound I (R=Me, M=H, X=H) has the following minimum inhibiting concentrations (in y/ml) as contrasted with the following list of bacteria: SARCINA LUTEA 60.19 STAPHYLOCOCCUS AUREUS 60.19 ESCHERICHIA COLI 6.25 KLEBSIELLA PNEUMONIAE 1.56 PROTEUS VULGARIS 3.12 PSEUDOMONAS AERUGINOSA > 100 ALCALIGENES FAECALIS 12.5 STAPHYLOCOCCUS EPIDERMIDIS 0.19 BORDETELLA BRONCHISEPTICA 50 MICROCOCCUS FLAVUS 0.39 ENTEROBACTER LIQUEFACIENS 100 STREPTOCOCCUS f. LANCEFIELD 50 CANDIDA ALBICANS > 100 BACILLUS SUBTILIS 60.19 BACILLUS PUMILUS 0.19 SALMONELLA PARATYPHI 3.12 SALMONELLA TYPHI 1.56 SACCHAROMYCES CEREVISIAE 25 WHAT WE CLAIM IS: 1. Compounds of the formula

wherein R = H or an alkyl group, M = H, an alkali metal, NH4, or an alkaline earth metal, X = H. an alkyl group. a halogen or hydroxyl, Z = H or a methoxy group.
2. Compounds according to Claim 1, in the form of non-toxic pharmaceutically acceptable salts.