Isomerization of beta -lactam compounds

摘要

Compounds of the formula (I): <IMAGE> (I) wherein R is an ethyl group which may optionally be substituted and n is 0 or 1, or a physiologically acceptable salt thereof, can be produced by subjecting to isomerization a compound of the formula (II): <IMAGE> (II) wherein R and n have the same meaning as defined above, or a salt thereof, by using a quaternary ammonium halide and are useful as a bactericide or disinfectant, and also a synergistic effect with penicillin and/or cephalosporin antibiotic agents. Among the compounds of the formula (I), compounds shown by the formula: <IMAGE> wherein R6 is H or -SO3H, as well as salts thereof, are novel.