| 摘要 |
A process for preparing cephalosporins of the structure: <IMAGE> I where R is any of hydrogen, C1 to C4 alkyl, t-butoxy, benzyloxy, cyano-methyl, thienyl-methyl, furyl-methyl, naphthyl-methyl, phenyl-methyl, phenoxy-methyl, phenoxy-isopropyl, pyridyl-4-thiomethyl and tetrazolyl-1-methyl; R1 is any of hydroxyl, C1 to C4 alkoxy, benzyloxy, p-methoxy- (or nitro-) benzyloxy, benzhydryloxy, triphenylmethoxy, phenacyloxy, p-halophenacyloxy and trichloroethoxy; Z is any of hydrogen, hydroxyl, -O-CO-C1-C4 alkyl, -O-C1-C4 alkyl, -Br, -I, -Cl, -N3, -NH2, -O-CO-CH3, -O-CO-NH2 and an -S-mononuclear nitrogen heterocyclic ring, BY REACTING COMPOUNDS OF THE STRUCTURE: <IMAGE> II (E isomer) <IMAGE> III (Z isomer) IN WHICH R, R1, and Z are as above defined; R2 and R3 are the same or different and represent a C1 to C4 alkyl, a mononuclear aryl ring, -CN, a mononuclear heterocyclic ring or the radicals -COR4, COOR4, -PO(OR4)2, -CO-NHR4 or R2 and R3 together may represent: <IMAGE> where T represents >CH2, -N-R4; and R4 is lower alkyl, a mononuclear aryl ring or a mononuclear heterocyclic ring, ALONE OR AS MIXTURES WITH EACH OTHER IN A SUITABLE SOLVENT AT A TEMPERATURE BETWEEN -100 AND +120 DEG C with a strong base to give compounds of formula I that are a mixture of DELTA 2 and DELTA 3 cephem-derivatives from which the DELTA 3 cephem derivatives can be obtained. |
