Regioselective synthesis of substituted tetrahydrochromeno[2,3- d ]pyrimidin-2-ones and -pyrimidine-2-thiones

The regioselective synthesis of the substituted (4 R *,10a R *)-4-aryltetrahydro-2 H -chromeno[2,3- d ]pyrimidin-2-ones, -pyrimidine-2-thiones and (4 R *,5 R *,6 R *)-5-acetyl-6-aryl-4-(2,4-dihydroxyphenyl)hexahydropyrimidin-2-ones, -hexahydropyrimidine-2-thiones by the reaction of the appropriate 5-acetyl-4-aryldihydropyrimidin-2-ones and -pyrimidine-2-thiones with 1,3-benzenediols was described. A plausible mechanism of the acid catalyzed rearrangement of resorcinol-substituted hexahydropyrimidin-2-ones and -pyrimidine-2-thiones to chromeno[2,3- d ]pyrimidin-2-ones and -pyrimidine-2-thiones, respectively, was suggested.