Phosphorus oxychloride → Methyl 5-(acetoxymethyl)-7-chloro-s-triazolo[1,5-a]pyrimidine-2-carboxylate

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Reaction Steps

A suspension of 100 mg (0.38 mmol) of methyl 5-(acetoxymethyl)-4,7-dihydro-7-oxo-s-triazolo[1,5-a]pyrimidine-2-carboxylate in 7 ml of phosphorus oxychloride is held under reflux for 6 hours and subsequently concentrated in a vacuum. The residue is dissolved in dichloromethane. The solution is washed with ice/water, dried over sodium sulphate and concentrated. After crystallization from methanol/diethyl ether there are obtained 70 mg of methyl 5-(acetoxymethyl)-7-chloro-s-triazolo[1,5-a]pyrimidine-2-carboxylate as brown crystals of melting point 120° C.

Provenance & Evidence