Bifunctional chelating agents. Part 1. 1-(p-Aminophenethyl)-ethylenediaminetetra-acetic acid

Abstract

The synthesis of a new bifunctional analogue of ethylenediaminetetra-acetic acid (EDTA), 1-(p-aminophenethyl)ethylenediaminetetra-acetic acid (13), from the amide of 2-amino-4-phenylbutyric acid (8) by reduction with diborane and acetylation to give compound (9), followed by nitration to afford the isomeric NN′-diacetyl-1-(p-nitrophenethyl)ethylenediamines [para-(10a) to ortho-(10b) ratio 9 : 1] of (10a) hydrolysis to compound (11), and tetra-alkylation to afford the acid (12), is described. This synthesis by-passes some of the inherent difficulties in the synthesis of the analogous 1-(p-nitrophenyl)-ethylenediamine system.