GB1348918A - Method for producing penicillins - Google Patents

Abstract

1348918 Preparing penicillins TAKEDA YAKUHIN KOGYO KK 19 April 1971 [21 Feb 1970] 21964/71 Addition to 1289358 Heading C2A Penicillins of general Formula I and salts thereof, wherein each of R 1 and R 2 which may be the same or different is hydrogen, C 1 to C 12 alkyl or cycloalkyl, C 7 to C 10 aralkyl, or a substituted or unsubstituted phenyl, pyridyl, naphthyl or thienyl group, the substituent being one or more of nitro, sulpho, carboxyl, halo, C 1 to C 6 alkyl or C 1 to C 6 alkoxy, or R 1 and R 2 together form a C 4 to C 6 polymethylene group, are prepared by reacting a tin ester of 6-aminopenicillanic acid of Formula II wherein R 3 , R 4 and R 5 are each the same or different hydrocarbon residues, with an acylating agent corresponding to the carboxylic acid of Formula III wherein R 1 and R 2 are as defined above, and hydrolysing the ester group of the product. The tin ester (II) may be prepared by reacting 6-amino-penicillanic acid with a compound of Formula IV wherein R 3 , R 4 and R 5 are hydrocarbon groups (e.g. C 1 to C 4 alkyl or phenyl). The preferred acylating agents are the acid halides, anhydrides or mixed anhydrides, azides, active esters, azolides or condensation products (e.g. with a carbodiimide, a keteimine or an isoxazolium salt) of the acid (III). Pharmaceutical compositions comprise a penicillin of Formula (I) or a normal or acid salt thereof and a pharmaceutical carrier or diluent.