ChemInform Abstract: A Convenient Synthesis of Tricyclic Purine Derivatives

A convenient synthesis of new heterocycles such as 7,8-dihydro-1H-imidazo[2,1-i]purin-5(4H)-ones (2, n = 0) and 5,6-dihydro-1H-imidazo[2,1-b]purin-9(8H)-ones (3) was described. The syntheses of 2 and 3 were accomplished by treatment of 6-methylthio-7H-purin-2(3-H)-ones 7 or 2-benzylthio-1-methyl-9-triphenylmethyl-9H-purin-6(1H)-one (15) with appropriate aminoalcohol followed by dehydrative cyclization using thionyl chloride. Compound 15 was efficiently prepared by benzylation of 6-hydroxy-2-mercaptopurine (12) followed by tritylation and N-methylation.