Hard and soft electrophilic and nucleophilic dissymmetry of α-oxoketenedithioacetals and p-nitro-o-phenylenediamine exploited to achieve the regioselectivity in the synthesis of 2-thiomethyl ether substituted isomer of the privileged nucleus of 1,5-benzodiazepines over to its 4-substituted isomers

Abstract

An exclusive regioselective formation of 2-thiomethyl ether substituted isomer of the privileged nucleus of 1,5-benzodiazepines was achieved from the reaction of p-nitro-o-phenylenediamine with a variety of α-oxoketene dithioacetals derived from several active methylene compounds, by exploiting the strategy based on the variation of electrophilicity of the two electrophilic centers of α-oxoketene dithioacetals and the hard and soft nucleophilic profiles of the p-nitro substituted o-phenylenediamines. An exclusive regioselective formation of 2-thiomethyl ether substituted isomer of the privileged nucleus of 1,5-benzodiazepines was achieved from the reaction of p-nitro-o-phenylenediamine with a variety of α-oxoketene dithioacetals derived from several active methylene compounds.