Methyl iodide → (2-Cyclopropyl-4-methyl-7-oxo-4,7-dihydro-pyrazolo[1,5-a]pyrimidin-6-yl)-acetic acid ethyl ester

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Reaction Steps

To a suspension of (2-cyclopropyl-7-oxo-4,7-dihydro-pyrazolo[1,5-a]pyrimidin-6-yl)-acetic acid ethyl ester (80 mg, 0.3 mmol, 1 eq) described in example 90 in tetrahydrofuran (2 mL) was added sodium hydride (16 mg, 3.9 mmol, 1.3 eq). The mixture was stirred during 30 min at room temperature and methyl iodide (30 μL, 0.5 mmol, 1.5 eq) was added. The mixture was stirred at room temperature for 5 h. The mixture was then diluted with ethyl acetate (5 mL) and water (5 mL) was added. The aqueous layer was extracted with ethyl acetate (2×10 mL) and the aqueous phases were dried over magnesium sulfate, filtered and evaporated in vacuo. The crude residue was purified by flash chromatography using cyclohexane and ethyl acetate (100/0 to 0/100) to afford the expected compound as white powder (16 mg, 59% yield).

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