Studies on fused pyrimidine derivatives. Part 13. Thermal ene reaction of 6-(alk-2-enylamino)-5-[(substituted imino)methyl]-1,3-dimethylpyrimidine-2,4(1H,3H)-diones leading to pyrimido[4,5-b]azepines

Abstract

6-(Alk-2-enylamino)-1,3-dimethyl-5-[(substituted imino)methyl]pyrimidine-2,4(1H,3H)-diones, obtained from 6-(alk-2-enylamino)-5-formyl-1,3-dimethylpyrimidine-2,4(1H,3H)-diones 1 and primary amines, participate in the intramolecular ene reaction (Type III) leading to pyrimido[4,5-b]azepine derivatives.