A. A. Yavolovskii

Novel polycyclic pyrimidines

Methods are reported for preparing the novel pyrimidines 7,8-dihydro-9H-1,2,5-chalcodiazolo[3,4-d]thiazole[2,3-b]pyrimidin-4-ones and their N-oxides.

Reactions of 3-(?-hydroxyethyl)-8-thiaxanthine

Depending on the base used, reaction of 3-(Β-hydroxyethyl)-8-thiaxanthine with p-toluenesulfonylchloride either stops at the stage of formation of the tosylate or gives 1,2,5-thiadiazolo[3,4-d]oxazolidino[2,3-b]pyrimidin-9(4H)-one. Upon treatment with ammonia or methylamine, both of these compounds react to give 3-(Β-hydroxyethyl)-8-thiaguanines.