Synthesis of 3-Aroylnicotinonitriles from Aroylketene Dithioacetals

The Knoevenagel adducts of 2-aroyl-3,3-bis(alkylsulfanyl)acrylaldehydes and malononitrile were cyclized in the presence of diisopropylamine to afford 5-aroyl-2,6-bis(methylsulfanyl)nicotinonitriles. Cyclization in the presence of aqueous ammonia gave 2-amino-5-aroyl-6-(methylsulfanyl) nicotinonitriles. A multicomponent reaction involving aroylketene dithioacetals, malononitrile and Vilsmeier reagent gave 5-aroyl-2-chloro-6-(methylsulfanyl)nicotinonitrile.