Synthesis of Novel 4-(1,3,2-Diazaphosphinin-5-yl)-1,2-Dihydrothieno[3,2-d][1,2,3] Diazaphosphinines: Cyclization of 5-[(2-Thienyl)Methyl]Hydrazono-2-Oxido-2-Phenyl-4-(Trifluoromethyl)-1H-1,3,2-Diazaphosphinine with Phosphorus Halides

Abstract

Synthesis of novel 4-(1,3,2-diazaphosphinin-5-yl)-1,2-dihydrothieno[3,2-d][1,2,3] diazaphosphinines 5-8 was achieved. The methodology depended on preparation of 5-[(2-thienyl)methyl]hydrazono-2-oxido-2-phenyl-4-(trifluoromethyl)-1H-1,3,2-diazaphosphinine (4) through the cyclization of 2-[(dimethylamino)methylene]-4,4,4-trifluoro-1-(2-thienyl)-butane-1,3-dione (2) with phenyl phosphonic diamide, followed by hydrazine hydrate. Cyclization of the hydrazone 4 with some phosphorus halides at refluxing pyridine gave the target products in acceptable yields.