N,N-Dimethylaniline → Ethyl 7-chloro-3mesityl-2,5-dimethylpyrazolo[1,5-a]pyrimidin-6-carboxylate

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Reaction Steps

Five droplets of N,N-dimethylaniline was added to a solution of ethyl 3-mesityl-2,5-dimethyl-7-oxo-4,7-dihydropyrazolo[1,5-a]pyrimidin-6-carboxylate (3 g, 8.49 mmol) in phosphorus oxychloride (80 g), followed by heating under reflux for four hours. The reaction mixture was added to ice and stirred for a while. Then, the mixture was extracted with ethyl acetate, and the organic layer was washed with an aqueous saturated solution of sodium bicarbonate and brine, dried over anhydrous magnesium sulfate and evaporated. The residue was purified by silica gel column chromatography (15-30% ethyl acetate/hexane), to give the title compound (1.94 g).

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