NEW STARTING COMPOUNDS FOR PREPARING CEPHEM COMPOUNDS AND PROCESSES FOR THEIR PREPARATION

摘要

Cephem compounds of the formula: …… wherein R<1> is amino or a protected amino group;… R<2> is cyclo (lower) alkenyl;… R<3> is carboxy or a protected carboxy group;… R<4> is hydrogen or a group of the formula:… -CH2-R<4a>… [wherein R<4a> is acyloxy, amino (lower) alkylthio, a protected amino(lower) alkylthio group, pyridinium which may have suitable substituent(s) or a heterocyclicthio group which may have suitable substituent(s)], and R<5> is hydrogen or lower alkyl, with proviso that R<3> is COO<-> when R<4a> is pyridinium which may have suitable substituent(s), and pharmaceutically acceptable salts thereof and process for their preparation, and also a pharmaceutical composition comprising, as an effective ingredient, the above compound in association with a pharmaceutically acceptable, substantially nontoxic carrier or excipient. The invention also relates to the starting compounds …… and their preparation.