Process for the preparation of diketopiperazines

摘要

Diketopiperazines of the formula <IMAGE> in which R<1>, R<2>, A and B have the meanings given in the description can be prepared by a novel process in which amino acids of the formula <IMAGE> are reacted with phosphorus chlorides of the formula R-PCl2 (III> in which R has the meaning given in the description in the presence of a tertiary amine and, if appropriate, in the presence of a diluent and the resulting phosphites of the formula <IMAGE> are reacted with amino acids of the formula <IMAGE> in the presence of a tertiary amine and, if appropriate, in the presence of a diluent. Novel phosphites of the formula (IV).