Patent ID: 7781581

Claim:
A process for the preparation of 5-amino-3H-thiazolo[4,5-d]pyrimidin-2-one of formula comprising: (i) halogenating a 2,4-diaminopyrimidine of formula to form 2,4-diamino-5-halo-pyrimidine of formula wherein X represents halo selected from F, Cl, Br, and I; (ii) cyclocondensing the 2,4-diamino-5-halo-pyrimidine to form 5-amino-3H-thiazolo[4,5-d]pyrimidin-2-thione of formula (iii) oxidizing the 5-amino-3H-thiazolo[4,5-d]pyrimidin-2-thione to form 5-amino-3H-thiazolo[4,5-d]pyrimidin-2-one.