Process for preparing 6-/D(-)-Alpha-(4-ethyl-2,3-dioxo-1-piperazine-carboxamido)-phenylacetamido/pennicillanic acid.

摘要

Disclosed is a process for preparing 6-[D(-)-alpha-(4-ethyl-2,3-dioxo-1-piperazinecarboxamido)-phenylacetam ido] penicillanic acid as well as pharmaceutically acceptable alkali metal salts thereof of the formula (I) <CHEM> wherein A represents a hydrogen atom, a sodium atom or a potassium atom, wherein active thioesters of 4-ethyl-2,3-dioxo-1-piperazinecarboxylic acid of the formula (II) <CHEM> wherein R represents a 2-mercaptobenzimidazole radical, 2-mercaptobenzoxazole radical and preferably 2-mercaptobenzothiazole radical, is condensed with silylated form of 6-[D(-)-alpha-aminophenylacetatamido] penicillanic acid of the formula (III) <CHEM> The compound of the formula II is a novel compound. h