Fused pyrimidine systems: XVII. Arylsulfenylation of 5-allylpyrimidine-4(3H)-one derivatives. Synthesis of arylsulfanyl-substituted 5,6-dihydrofuro[2,3-d]- and 6,7-dihydro-5H-pyrano[2,3-d]pyrimidines

Abstract

5-Allylpyrimidine-4-ones react with arylsulfenyl chlorides in dichloromethane with the formation of 5-[(2-arylsulfanyl)-3-chloropropyl]-pyrimidine-4-ones that under the action of sodium acetate undergo cyclization into 6-arylsulfanyl-6,7-dihydro-5H-pyrano[2,3-d]pyrimidines. At performing similar reactions in nitromethane an intramolecular electrophilic cyclization occurs affording 6-[(arylsulfanyl)methyl]-5,6-dihydrofuro[2,3-d]pyrimidines.