SYNTHESIS OF DERIVATIVES OF THIAZOLO[4,5-D]PYRIMIDINE .I.

Reaction of 2,4-diamino-5-bromo-6-hydroxypyrimidine with thiourea gave the isothiouronium salt, which with alkali afforded di-(2,4-diamino-6- hydroxypyrimidin-5-yl) disulphide and not the thiazolo[4,5-d]pyrimidine claimed by an earlier worker. Kaufmann thiocyanation of 2,4-diamino-6-hydroxypyrimidine yielded the 5-thiocyanato-compound, which did not readily cyclise to a thiazolo[4,5-d]pyrimidine as previously claimed by other workers. Cyclisation of the thiocyanato-compound has been effected with acetic anhydride. Deacetylation of the resulting diacetamido-derivative gave 2,5-diamino-7-hydroxythiazolo[4,5- d]pyrimidine.