| abstract |
A 7 beta -acylamino-7 alpha -alkoxycephalosporin is prepared by reacting a 7-acylaminocephalosporin with a halogenating agent to give an iminohalide, reacting the latter compound with a base to give a keteneimine, reacting the latter compound with a halogen to give an alpha -halogeno iminohalide, reacting the latter compound with an alkali metal alkoxide and consecutively either subjecting the resulting compound to hydrolysis, or reacting the resulting compound with an acid or a halogenosilyl compound followed by treating the resulting compound with water. |