Process for preparing ampicillin

摘要

A process for preparing ampicillin trihydrate is disclosed which comprises acylating silylated 6-aminopenicillanic acid with D(-)- alpha -phenylglycylchloride hydrochloride directly in the silylation reaction mixture in the presence of urea as an acid acceptor, hydrolyzing the reaction product and precipitating ampicillin-trihydrate from the resulting aqueous solution. The amounts of reactants, in particular of solvents and water, are adjusted to provide good yields of a product of high purity.