Reactions of amino-acids co-ordinated to metal ions. Part 1. Investigation of the condensation of formaldehyde and metal-co-ordinated glycine

Abstract

The condensation reaction of formaldehyde with glycine or glycine Schiff bases co-ordinated to Co^III, Cu^II, and Ni^II has been studied. The reaction leads invariably to α-hydroxymethylserine. The influence of the metal ion, the charge of the complex, pH, and the ratio of the reactants are discussed, together with the effect of Schiff-base formation. With [Cu(glyO)₂](glyO = glycinate) the condensation of formaldehyde at the α-carbon atom is preceded by condensation on the amino-group and is followed by cyclization to give an oxazolidine-type ring. No evidence for such a mechanism has been obtained in the case of [Co(en)₂(glyO)]²⁺(en = ethylenediamine).