Investigations in the imidazole series

Purinyl(theophyllinyl)-8-mercapto aldehydes and their acetals were synthesized by the reaction of 8-thio derivatives of purine and theophylline with -halo aldehydes and their acetals. The IR spectra demonstrated that the indicated aldehydes exist in the solid state as tautomeric forms — 3-hydroxy derivatives of thiazolino2,3-f]purines(xanthines). Dehydration of the latter gave thiazolo2,3-f]purine, 6,8-dimethylthiazolo2,3-f]xanthine, and their 2-alkyl-substituted derivatives. The structures of the three-ring compounds were established by reductive desulfuration to 7-alkyl-substituted purines and theophyllines.See 1] for communication LXXVI.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 996–999, July, 1972.