Synthesis of a water-soluble chiral NMR shift reagent: ( S)-PDTA

Abstract

A five-step synthesis of the water-soluble chiral polydentate ligand, ( S)-PDTA [( S)-PDTA = N, N, N′, N′-tetrakis[(hydroxycarbonyl)methyl]-( S)-1,2-diaminopropane] starting from l-alanine has been worked out, via steps with retention of chirality. Total yield is 50.7% (average of ∼88% for each step), while published methods report 33.4% total yield over four steps.