NEW SYNTHESES OF SUBSTITUTED 1,2-DIHYDROXY-1,2-BISPHOSPHONYLETHANES

Abstract

Substituted 1,2-dihydroxy-1,2-bisphosphonylethanes were synthesized by reacting glyoxal with phosphorous acid triesters. The intermediate adduct resulting from a nucleophilic attack of phosphorus on the carbonyl carbon was protonated and dealkylated by a third reagent such as methanol or hydrogen chloride. Evidence for the reaction mechanism was obtained by isolation and identification of dimethylether evolved as a byproduct from the reaction of glyoxal with trimethyl phosphite in the presence of methanol. The yield of substituted 1,2-dihydroxy-1,2-bisphosphonylethanes thus prepared was significantly higher than that of the previously reported reactions of glyoxal with phosphorous acid diesters. In addition, substituted 1,2-dihydroxy-1,2-bisphosphonylethanes were prepared by reacting 2-hydroxy-2-phosphonylethanals with phosphorous acid triesters.