Abstract
Treatment of thiazolo [3, 2-b] pyridazinium perchlorates (I) with potassium cyanide in water-acetonitrile furnishes 8-cyano-4, 7-dihydrothiazolo [3, 2-b] pyridazine-7-ones [II] and anhydro-7-cyano-5, 8-dihydro-8-oxothiazolo [3, 2-b] pyridazinium hydroxides (III), the structure of which are elucidated by chemical properities, infrared, nuclear magnetic resonance, ultraviolet and mass spectrometry, and elemental analysis. Examination of the reaction by conducting under nitrogen or oxygen stream and with or without water as the solvent and by monitoring the presence of organic free radical by means of electron spin resonance spectroscopy suggests that the reaction is initiated by the nucleophilic attack of the cyanide either at C8- or C7-position of the pi-deficient thiazolo [3, 2-b] pyridazinium system (I), followed by incorporation of the atmospheric oxygen to form hydroperoxide via radical anion species.
