1-(CYANOMETHYL)BENZOTRIAZOLE AS A CONVENIENT PRECURSOR FOR THE SYNTHESIS OF 2-SUBSTITUTED THIAZOLES

Treatment of 1-(cyanomethyl)benzotriazole with hydrogen peroxide followed by a Lawesson reagent afforded by a Lawesson reagent afforded (benzotriazol-1-yl)thioacetamide which condensed with alpha-halo carbonyl compounds (Hantzsch thiazole synthesis) to give the corresponding 2-(benzotriazol-1-ylmethyl)thiazoles. Lithiation of 2-(benzotriazol-1-ylmethyl)-4-phenylthiazole with butyllithium occurred exclusively at the methylene group, and subsequent quenching of the resulting anion with alkyl halides produced the corresponding alkylated products in good yields. Treatment of these intermediates with Grignard reagents in toluene or with electron-rich heterocycles in the presence of zinc bromide resulted in the displacement of benzotriazole to afford the corresponding thiazoles with elaborated 2-substituents.