Novel Pyrazole and Isoxazole Derivatives from Deoxybenzoin as Intermediates for the Synthesis of New Chemical Entities

In the last decades a number of pyrazole and isoxazole derivatives have been introduced in clinical practice. The therapeutic effectiveness of these agents has been bounded by a number of limiting factors. Due to this, the development of novel, selective, potent and safe agents remains in high priority in medicinal chemistry research. Synthans, such as oxoketenedithioacetals are known in the literature to offer unprecedented opportunity to a chemist in the synthesis of a wide variety of difficultly accessible heterocyclic compounds. It has been demonstrated that oxoketenedithioacetals react smoothly with smoothly with nucleophiles and offered a very facile one pot synthetic entry to five, six and seven membered heterocyclic rings. The present work describes the synthesis of oxoketenedithioacetal derivative of deoxybenzoin 1.02 and their subsequent conversion to pyrazole derivatives 1.03, 1.04 a, 1.04 b and to isoxazole derivatives, 1.05, 1.06 a, 1.06 b respectively as shown in Scheme 1.1. The structures of the compounds have been established analytically. These structures can help the medicinal chemists to use them as intermediates to design various drug candidates possessing a number of pharmacological