Patent GB-1525739-A (GB)
Title: Cephalosporin derivatives
IPC: A61K31/545
Filed: 1975-11-27
Abstract: 1525739 3-Substituted 2- or 3-cephem derivatives ELI LILLY & CO 27 Nov 1975 [4 Dec 1974] 48753/75 Heading C2C Novel 3-substituted 2- or 3-cephem derivatives of the general formula wherein the dotted line represents a single carbon-carbon bond at the #<SP>3</SP> or #<SP>2</SP> position; R 2  and R 3  are each hydrogen or taken together form the group =C=O, or wherein R 2  taken singly is hydrogen and R 3  taken singly is:- (a) a group of the formula -COOR 4  wherein R 4  is C 1-6  alkyl, C 3-6  alkenyl, C 1-6  haloalkyl, 2,2,2-tri-haloethyl, methoxybenzyl, nitrobenzyl, benzyl or phenyl; or (b) a group of the formula -COSR 5  wherein R 6  is C 1-6  alkyl, phenyl, or benzyl; or (c) a group of the formula -CONR 6 R 8  wherein R 6  is hydrogen, C 1-6  alkyl, benzyl, phenyl, or tolyl and R 8  is hydrogen, C 1-6  alkyl or benzyl; or wherein R 6  and R 8  and the nitrogen atom to which they are bonded together form a 5 or 6 membered heterocyclic ring; or (d) a group of the formula -COR 7  wherein R 7  is C 1-6  alkyl, di(C 1-3  alkoxycarbonyl)- methyl, benzyl or phenyl; and wherein R is hydrogen or a carboxylic acid protecting ester forming group; R<SP>1</SP> 1  is hydrogen or methoxy; and wherein R 1  is hydrogen or an acyl group of the formula R<SP>1</SP>CO- wherein R<SP>1</SP> is (a) C 1-7  alkyl, C 3-7  alkenyl, cyanomethyl, halomethyl, 4-amino-4-carboxybutyl or 4-protected amino- 4-protected carboxybutyl; or (b) C 1-6  alkoxy, benzyloxy, 4-nitrobenzyloxy or 4-methoxybenzyloxy; or (c) the group -R<SP>11</SP> which is 1,4-cyclohexadienyl, phenyl, or substituted phenyl wherein the substituents are 1-3 halogens, hydroxy, nitro, cyano, trifluoromethyl, C 1-4  alkyl, C 1-4  alkoxy, carboxy, carboxymethyl, hydroxymethyl, aminomethyl, or protected aminoethyl; or (d) an substituted alkyl group of the formula R<SP>11</SP>-(Y)m-CH 2 - wherein R<SP>11</SP> is as defined above, X is O or S, and m is 0 or 1; or (e) a substituted alkyl group of the formula R<SP>111</SP>CHW- wherein R<SP>111</SP> is R<SP>11</SP> as defined above, 2-thienyl, or 3-thienyl; W is hydroxy or protected hydroxy, carboxy or protected carboxy, or amino or protected amino; or (f) a heteroarylmethyl group of the formula R<SP>1111</SP>CH 2  wherein R<SP>1111</SP> is 2-thienyl, 3-thienyl, 2-furyl, 3-furyl, 2-thiazolyl, 5-tetrazolyl or 1-tetrazolyl; and when R is hydrogen, the pharmaceutically acceptable non-toxic salts of the acids represented thereby; with the limitations that when R 3  is the double bond is in the #<SP>3</SP> position; and when the group is -N=C=O, neither R nor R 1  can be hydrogen, are prepared by heating a 3-azidocarbonyl-2- or 3-cephem derivative of the general formula wherein RE is a carboxylic acid-protecting esterforming group, optionally reacting the resulting 3-isocyanato-2- or 3-cephem with a nucleophilic reagent B : H or a source of anion B : - in which B is R 4 O-, R 5 S-, R 6 R 8 N- or R 7 - to give the corresponding compound in which R 3  is -COOR 4 , -COSR 5 , -CONR 6 R 8  or -COR 7 , optionally reducing the resulting compound in which R 3  is -COOR 4  to give the corresponding compound in which R 3  is H, optionally cleaving the 7-position side chain to give the corresponding 7-amino-cephalosporin, and optionally removing the carboxylic acid-protecting esterforming group to give the corresponding acid. Benzhydryl 7-(2-thienylacetamido)-3-azidocarbonyl-2-cephem-4-carboxylate is prepared by reacting the corresponding 3-formyl derivative with ethylene glycol and p-toluenesulphonic acid, treating the resulting 3-(1,3-dioxolan-2-yl) derivative with N-bromosuccinimide and azobisisobutyronitrile, treating the resulting 3-(2- bromoethoxycarbonyl) derivative with Nal, reacting the resulting 3-(2-iodoethoxycarbonyl) derivative with Zn dust in glacial acetic acid and DMF, treating the resulting 3-carboxy derivative with ethyl chloroformate and reacting the resulting 3-ethoxycarbonyloxycarbonyl derivative with sodium azide. Benzhydryl 7-(2-thienylacetamido)-3-formyl-2- cephem-4-carboxylate is prepared by reacting 7 - (2 thienylacetamido) - 3 -hydroxymethyl -2- cephem - 4 - carboxylic acid with diphenyldiazomethane and oxidizing the resulting benzhydryl ester with chromic acid. Benzhydryl 7 - (2 - thienylacetamido) - 7 - methoxy - 3 - formyl - 2 - cephem - 4 - carboxylate is prepared by treating 7-(2-thienyl-acetamido)-7- methoxy-3-acetoxymethyl-3-cephem-carboxylic acid with acetic anhydride in pyridine, hydrolysing the resulting 2-cephem derivative with NaOH oxidising the resulting 3-hydroxymethyl-2-cephem with chromic acid and esterifying the resulting 3-formyl-2-cephem acid with diphenyldiazomethane.