Chemical Synthesis of the Tryptophan Path Intermediate l-(o-Carboxyphenylamino)-l-deoxy-D-ribulose 5-Phosphate

Abstract

THE Amadori compound l-(o-carboxyphenylamino)-l-deoxy-D-ribulose 5-phosphate has been shown to be an intermediate of tryptophan biosynthesis in Aerobacter aerogenes^1,2 and Escherichia coli³. In the course of an attempt to synthesize chemically the suggested intermediate, N-5′-phosphoribosyl) anthranilic acid, I found that a compound with the properties and spectral characteristics of the Amadori rearrangement product was formed⁴. The method of synthesis of this compound has not been previously described, as until recently I have not used it in biological systems. The product (synthesized in 1960) has recently been used as a substrate in investigations of indoleglycerolphosphate synthetase in extracts of different micro-organisms. Since 1960 the intermediate, in the form of a sodium salt and another sample in the form of a barium salt, has survived a trip round the world and storage under refrigeration at 4° and − 15° C.