Synthesis of 4‐methylthio‐2(1H)‐pyridone derivatives using ketene dithioacetals

Abstract Reaction of various active methylene compounds with ketene dithioacetals, bis(methylthio)methylenemalononitrile (1a) and bis(methylthio)methylenecyanoacetamide (1b) gave the corresponding 3‐cyano‐4‐methylthio‐2(1 H )‐pyridone derivatives. The transformation of 4‐methylthio‐2‐oxo‐2 H ‐pyran‐3‐carbonitrile in‐to 4‐methylthio‐2(1 H )‐pyridone derivatives was also described.