PROCESS FOR PRODUCTION OF PHENYLALANINE DERIVATIVES HAVING QUINAZOLINEDIONE SKELETONS AND INTERMEDIATES FOR THE PRODUCTION.

摘要

A process for the production of phenylalanine derivatives having quinazolinedione rings as represented by the general formula (1) or pharmaceutically acceptable salts thereof:(1) which comprises the following steps (a), (b) and (c): the step (a) of reacting an acylphenylalanine derivative represented by the general formula (2): (2) with a carbonyl-introducing agent and a specific anthranilic acid derivative to form a corresponding carboxy asymmetric urea derivative, the step (b) of converting the carboxy asymmetric urea derivative into a corresponding quinazolinedione in the presence of a carboxyl-activating agent, and the optional step (c) comprising the N-alkylation step of replacing the hydrogen atom attached to the nitrogen atom constituting the quinazoline- dione ring by an alkyl group with an N-alkylating agent and/or the deblocking step of deblocking R3' (a group corresponding to R3) when R3' is in a protected state. According to the process, phenylalanine derivatives having quinazolinedione skeletons can be produced in high yield favorable for industrialization.