An Unexpected Synthesis of 2,3-Bis(methylthio)-1,4-di(het)arylbut-2-ene-1,4-diones and Their Cyclocondensation with Hydrazine for the Synthesis of 4,5-Bis(methylthio)-3,6-di(het)arylpyridazines

Abstract An unexpected formation of novel 2,3-bis(methylthio)-1,4-di(het)arylbut-2-ene-1,4-diones is reported, when methyl ketones are reacted with α-oxodithioesters in the presence of sodium hydride in DMF followed by treatment with methyl iodide. A potential application of these key intermediates for the synthesis of unreported 4,5-bis(methylthio)-3,6-di(het)arylpyridazines is explored by reacting them with hydrazine in the presence of potassium hydroxide in isopropyl alcohol. Possible mechanisms for the formation of 2,3-bis(methylthio)-1,4-di(het)arylbut-2-ene-1,4-diones and 4,5-bis(methylthio)-3,6-di(het)arylpyridazines are proposed.