| 摘要 |
A process for the preparation of a compound of the formula (1): (I) or a salt or ester thereof wherein R is a methyl or ethyl group which process comprises the reaction of clavulanic acid or a salt or ester thereof with an oxonium salt of the formula (II): R3O? X.THETA. (II) wherein R is a methyl or ethyl group and X.THETA. is an anion and thereafter if desired performing one or both of the following reactions: (a) converting the thus formed ester into the acid or salt and (b) converting the thus formed acid or salt into an alternative ester or alternative salt. The compounds of formula (I) have utility as additives to enhance the effectiveness of penicillins and cephalosporius. The novel process is generally convenient, safer and often higher yielding than known processes. |
