The synthesis of pyridine derivatives from 3‐formylchromone

Abstract

Abstract 3‐Formylchromone ( 1 ) reacts with active methylene derivatives to yield condensation products 2a‐d, 10,11 and 12 . Treatment of 2a‐d with ammonia or methylamine gives pyridines 3–6 . Alternatively, reaction of 1 with enamine derivatives yields pyrido compounds 15, 17, 19, 21, 23 and 28 in one step. Factors determining the formation and regiospecificity of the pyridine ring forming reactions are also discussed.