Phosphorus pentachloride → 1H-Pyrazolo[4,3-d]pyrimidine, 7-chloro-1,3-dimethyl-5-(1-methylethyl)-

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Reaction Steps

A mixture of 10 g (0.048 mol) of 1,3-dimethyl-5-isopropyl-1H-pyrazolo[4,3-d]pyrimidin-7-ol and 10.2 g (0.049 mol) of phosphorus pentachloride in 70 ml of phosphorus oxychloride is stirred under reflux five hours and evaporated in vacuo. The residue is dissolved in 150 ml of methylene dichloride and stirred with 100 ml of a saturated solution of sodium bicarbonate. The organic layer is separated, dried over MgSO4, and evaporated in vacuo to to give 10.5 g of 7-chloro-1,3-dimethyl-5-isopropyl-1H-pyrazolo[4,3-d]pyrimidine, mp 87°-89° C. from pet ether.

Provenance & Evidence