Organomercury Compounds. XXVII. The Synthesis and Properties of Some Carboxylato- and Carboxy-pyridinylmercurials

Abstract

Decarboxylation of mercuric pyridine-2,3-dicarboxylate in hot dimethyl sulfoxide or hexamethylphosphoramide gives a mixture of 2-carboxylatopyridin-3-ylmercury(II) (major product) and 3- carboxylatopyridin-2-ylmercury(II) (minor product). The mixture reacts ( i ) with acidified halide ions ( Cl ^- or I^-) to yield a mixture of the corresponding carboxypyridinyl ( halogeno )mercury(II) derivatives, (ii) with tribromide ions to give the bromo ( carboxypyridinyl )mercury(ii) complexes, 3-bromopyridine-2-carboxylic acid, and 2-bromopyridine-3- carboxylic acid, and (iii) with iodide ions in hot aqueous acetic acid to yield bis (2-carboxypyridin-3-yl)mercury(II) hydrogen triiodomercurate (II). Solutions of the last compound in dimethyl sulfoxide deposit bis (2-carboxypyridin-3-yl)mercury(II). Reaction of pyridine-2,3-dicarboxylate ions with mercuric acetate in boiling aqueous acetic acid at pH 5.0-5.8 gives mercurated acetic acid as the sole organometallic product, and the reported¹ decarboxylation yielding 3-carboxylatopyridin-2-ylmercury(II) is not observed.