Synthesis of new functionalized aryl and pyridyl aminomethylenebisphosphonic acids and their derivatives via silicon-assisted methodology

摘要

The new convenient synthesis of functionalized aryl and pyridyl aminomethylenebisphosphonic acids and their derivatives has been developed via silicon-assisted methodology. New functionalized amino-methylenebisphosphonic acids containing pyridines moieties were obtained using unique reaction of tris(trimethylsilyl) phosphite with N-formyl aminopyridines and trimethylsilyl triflate as a catalyst under mild conditions. Intermediates - tetra(trimethylsilyl) aminomethylenebisphosphonates formed, were converted to the target acids by further treatment with methanol excess. In contrast the corresponding tetraethyl aminomethylenebisphosphonates were synthesized under heating (130 degrees C) of four component mixture (diethyl trimethylsilyl phosphite, triethyl orthoformate, aryl- or pyridylamine, and diethyl phosphite) in the presence of zinc chloride catalyst. The catalytic schemes of target substances formation are proposed and thoroughly discussed. (C) 2020 Elsevier B.V. All rights reserved.