Process for preparing 3-halogenated cephem derivative

摘要

PCT No. PCT/JP96/03298 Sec. 371 Date Jun. 3, 1997 Sec. 102(e) Date Jun. 3, 1997 PCT Filed Nov. 8, 1996 PCT Pub. No. WO97/17353 PCT Pub. Date May 5, 1997A process for preparing a 3-halogenated cephem derivative represented by the formula (2), characterized by causing a halogenating reagent to act on an allenyl beta -lactam compound represented by the formula (1) in the presence of a cuprous salt or cupric salt to obtain the 3-halogenated cephem derivative wherein R1 is a hydrogen atom, amino or protected amino, R2 is a hydrogen atom, halogen atom, lower alkoxyl, lower acyl, lower alkyl, lower alkyl having at least one selected from hydroxyl and protected hydroxyl as a substituent, hydroxyl or protected hydroxyl, R3 is a hydrogen atom or carboxylic acid protecting group, R4 is an aromatic compound residue which may have a substituent or nitrogen-containing aromatic heterocyclic compound residue which may have a substituent, and n is 0 to 2 wherein R1, R2 and R3 are as defined above, X is a halogen atom.