SYNTHESIS AND CHEMICAL PROPERTIES OF SUBSTITUTED 2-HYDROXY-2-PHOSPHONYLETHANALS AND 1,2-DIHYDROXY-1,2-BISPHOSPHONYLETHANES

Abstract The syntheses of 2-hydroxy-2-(dialkoxyphosphonyl)ethanals 1a-1h, and of 1,2-dihydroxy-1,2-bis(dialkoxyphosphonyl)ethanes 2a-2h by reactions of glyoxal with phosphorous acid diesters in acidic medium are reported. The base catalyzed isomerization of 2-hydroxy-2-(dialkoxyphosphonyl)ethanals 1 to formylmethylphosphates 3 was demonstrated by 31P NMR spectroscopy. The stability of 1,2-dihydroxy-1,2-bis-(dialkoxyphosphonyl)ethanes 2 towards bases was demonstrated and interpreted on the basis of their structural features. The reactions of glyoxal with O-(n-butyl)phenylphosphonite, diethyl-and diphenyl-phosphineoxide and the identification of their products are reported as well as the synthesis of 1,2-dihy-droxy-1,2-bis(dihydroxyphosphonyl)ethane 2m by acid-catalyzed hydrolysis of 1,2-dihydroxy-1,2-bis(di-alkoxyphosphonyl)ethanes and by hydrogenation of 1,2-dihydroxy-1,2-bis(dibenzyloxyphosphonyl)ethane 2f. The rate constant of the hydrogenation of 2f and the pKa values of the 1,2-dihydroxy-1,2-bis(dihydroxyphosphonyl)ethane 2m are also reported.