CEPHALOSPORINS

摘要

A process is disclosed for preparing a cephalosporin of structure: (III) where R is selected from the class consisting of hydrogen, alkyl having from 1 to 4 carbon atoms, cyano-methyl, thienyl-methyl, furyl-methyl, naphthyl-methyl, phenyl-methyl, phenoxy-methyl, phenyl-isopropyl, phenoxy-isopropyl, pyridyl-4-thiomethyl, tetrazolyl-1-methyl; R1 is selected from the class consisting of hydroxy, alkoxy having from 1 to 4 carbon atoms, trichloroethoxy, benzyloxy, p-methoxy-benzyloxy, p-nitrobenzyloxy, benzhydryloxy, triphenylmethoxy, phenacyloxy, p-halophenacyloxy; and Z is selected from the class consisting of hydrogen, hydroxy, -O-Alkyl, -O-CO-Alkyl, -Br, -I, -NH2, -O-COCH3, -O-CO-NH2, and an -S-mononuclear nitrogen heterocyclic ring, WHEREIN A COMPOUND OF STRUCTURE: where R, R1 and Z have the above meanings, is reacted with iodine in a suitable aqueous solvent at a temperature between 5 DEG and 80 DEG C in the presence of an oxide of a heavy metal or with a free radical initiator under the influence of light or heat, to give a compound of structure: (II) in which R, R1 and Z have the above meanings, AND THE SAID INTERMEDIATE (II) is reacted in a suitable solvent with a compound selected from the class consisting of inorganic and organic bases to finally give the desired compound (III) which is then isolated and purified in per se known manner.