PROCESS FOR THE PREPARATION OF N-SUBSTITUDED GLYCINE ACIDS OR GLYCINE ESTERS AND USE OF SAID PROCESS FOR INDIGO SYNTHESIS

摘要

Process for the preparation of an N-substituted glycine ester or an N-substituted glycine acid by reaction of a glyoxylic acid ester half-acetal or glyoxylicacid half-acetal with an amine and hydrogenation of the intermediate product formedby this reaction, and the use of the process in a process for the preparation of indoxyland indigo derivatives by cyclization of an N-arylglycine ester, prepared by the aboveprocess, in a molten alkali metal carbonate or alkaline earth metal carbonate with orwithout addition of an alkali metal amide, and if appropriate oxidation of the indoxylderivative formed by this reaction to give the corresponding indigo derivative.