Reaction of 2-cyano-3-(4-oxo-4H-chromen-3-yl)prop-2-enamide with some phosphorus reagents: synthesis of some novel diethyl phosphonates, 1,2,3-diazaphosphinanes, 1,2,3-thiazaphosphinine and 1,2-azaphospholes bearing a chromone ring

Abstract

Novel chromonyl phosphonic acid 3, diethyl chromonyl phosphonate 4, and diethyl chromonyl pyridinyl phosphonate 5 were obtained from treatment of 2-cyano-3-(4-oxo-4H-chromen-3-yl) prop-2-enamide (2) with phosphorous acid and its diesters. Also, an efficient route to functionalized phosphorus heterocycles such as 1,2,3-diazaphosphinane, 1,2,3-thiazaphosphinine and 1,2-azaphosphole bearing a chromone ring was achieved via reaction of compound 2 with some phosphorus sulfides and phosphorus tribromide. A key part of the reaction mechanisms is discussed. Structures of the new synthesized products were established on the basis of spectral data (IR, ESI-MS, 1H-, 13C and 31P-NMR spectra). An efficient route to functionalized phosphorus heterocycles such as 1,2,3-diazaphosphinane, 1,2,3-thiazaphosphinine and 1,2-azaphosphole bearing a chromone ring was achieved via reaction of 2-cyano-3-(4-oxo-4H-chromen-3-yl)prop-2-enamide with some phosphorus sulfides and phosphorus tribromide.