Base Induced Cyclocondensation of Arylhydrazines with α,β-Bis(methylthio)-α,β-unsaturated-1,4-diketones: A Novel Approach for the Synthesis of 1,3-Di(hetaryl/aryl)-4-methylthio-5-acyl-pyrazoles

We herein report the reaction between α-oxodithioesters and methyl ketones in the presence of sodium hydride and methyl iodide in DMF for the synthesis of symmetrical α,β-bis(methylthio)-α,β-unsaturated-1,4-diketones, which are novel key compounds. We explored potential application of these intermediates by reacting with arylhydrazines in the presence of potassium hydroxide in isopropyl alcohol at 75 °C, which afforded 1,3-di(hetaryl/aryl)-4-methylthio-5-acyl-pyrazoles in high yields and short reaction times. Wide substrate scope, development of novel key intermediates and pyrazoles, are the advantages of this protocol