New heterocyclic mono- and bis(α-hydroxymethyl)phosphinic acids:: Synthesis and CuII binding abilities

A simple and efficient method for the synthesis of (alpha-hydroxymethyl)phosphinic acids in a pyridine and imidazole series from their corresponding aldehydes and aqueous hypophosphorous acid was developed. The same reaction carried out with an excess of aldehyde in the presence of a mineral acid led mainly to the corresponding bis(alpha-hydroxymethyl)phosphinic acids in moderate yields. The coordination properties of these compounds towards Cull ions were determined. Additionally, it was found that [(hydroxy)-(2-pyridyl)- and (hydroxy)(4-pyridyl)methyl]phosphinic acids were easy to cleave in aqueous sulfuric acid solutions, to form phosphorus acid (H3PO3) and the corresponding pyridinemethanols. The kinetics of the cleavage reaction was studied. On the basis of the obtained results, a mechanism of the cleavage was formulated. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007).