Benzylidenemalonaldehydes: Synthesis of 4-aryl-2-dimethylamino-4H-1,3-oxazine-5-carboxaldehyde

Abstract

Reaction of substituted benzylidenemalonaldehydes Ia-Ic and thienylmethylenemalonaldehyde (Id) with dimethylcyanamide in boiling benzene afforded the corresponding 4-aryl-2-dimethylamino-4H-1,3-oxazine-5-carboxaldehydes III. Electronic requirements for this cyclization reaction are discussed in relation with general rules and further applicability.