Studies on Conjugated Nitriles. VII. Lewis Acid-Promoted Reaction of Active Methylene Compounds with Diethyl Phosphorocyanidate; Preparation of α, β-Unsaturated α-Aminophosphonates

Abstract

Reaction of diethyl phosphorocyanidate (DEPC) with dimethyl malonate (1a) and ethyl cyanoacetate (1b) in the presence of zinc chloride and triethylamine resulted in selective addition of 1a, b to the cyano group of DEPC to give α, β-unsaturated α-aminophosphonates (2a, b). In contrast, similar treatment of enolizable methyl acetoacetate (1c) and acetylacetone (1d) with DEPC gave the corresponding enolphosphates (4c, d) as a result of nucleophilic displacement on the phosphorus atom of DEPC. Conversion of the resulting α-aminophosphonate (2a) to uracil-6-phosphonates (6a, b) was achieved by treatment with phenyl isocyanate (5a) and isothiocyanate (5b), respectively.