Reaction of pyridoxal and its azomethines with hydrophosphoryl compounds

The products of carbonyl phosphonylation of pyridoxal with alkylphosphinic acid ethyl esters, phosphorous acid dialkyl esters have been obtained for the first time. In some cases, the products of addition are hydrolytically unstable and stabilize by forming internal betaine structures. The reaction of pyridoxal with phosphorous acid in alcohol solutions gives alkoxyfuropyridines possessing the iminium nitrogen atom. [GRAPHICS] .