Synthesis of some amino-substituted furanopyrimidines and styrylpyrimidines†

5-p-Chlorophenyl-6,6-dimethyl-5,6-dihydro-3H-furano[2,3-d]pyrimidine-4-one is readily converted to 4,6-dichloro-5-β-β-dimethyl-α- (p-chlorostyryl)pyrimidine by warming in phosphorus oxychloride and acetic acid, behavior which is in strong contrast to that of the analogous 5-phenyl derivative. The reaction provides a convenient source of 4-amino-6-chloro-5β,β-dimethyl-α- (p-chlorostyryl)pyrimidines and 4,6-diamino-5-β,β-dimethyl-α- (p-chlorostyryl)pyrimidines, compounds of potential biological interest.