VERFAHREN ZUR HERSTELLUNG EINES NEUEN ZWISCHENPRODUKTS FUER CEPHALOSPORINE

摘要

PURPOSE:To obtain the titled compound useful as a fungicide, easily in high yield, by reacting a specific novel compound with a specific cephem compound in the presence of boron trifluoride, etc. CONSTITUTION:The novel compound (syn isomer) of formula I [R<1> is H, (substituted) alkyl, aralkyl, aryl or heterocyclic group; R<2> is lower alkyl] [e.g. 2-(2- aminothiazol-4-yl)-2-(syn)methoxyiminoacetic acid amide, etc.] is made to react with the compound of formula II [R<3a> is COOH-protecting group; R<4> is (substituted) heterocyclic group bonded with 3-exomethylene group through C-N bond] {e.g. pivaloyloxymethyl=7-amino-3-[(5-methyl-1,2,3,4-tetrazol-2-ylmethyl]- DELTA<3>-cephem-4-carboxylate} in the presence of boron trifluoride or its complex compound to obtain the objective compound of formula III (R<3> is H or COOH- protecting group). The starting raw material of formula I can be produced according to the reaction formula.