Methyl iodide → Methyl 3-benzyloxy-5-methyl-4-oxo-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrazine-2-carboxylate

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Reaction Conditions

Reaction Steps

To a solution of methyl 3-benzyloxy-4-oxo-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrazine-2-carboxylate (300 mg, 0.966 mmol) in DMF (5 mL) was added iodomethane (74 μL, 1.20 mmol). The solution was cooled to 0° C., treated with NaH (36 mg, 1.49 mmol, 95% dispersion in oil), and stirred for 10 minutes. The reaction was removed from the ice bath and allowed to gradually warm to room temperature. The mixture was partitioned between EtOAc and brine, and the organic extract was dried over Na2SO4 and concentrated in vacuo. Purification by reverse phase chromatography on a C-18 column using a gradient elution of 95-5% H2O (0.1% TFA)/CH3CN (0.1% TFA) and collection and concentration of the appropriate fractions afforded the title product. 1H NMR (400 MHz, CDCl3) δ 7.54-7.53 (m, 2H), 7.37-7.28 (m, 3H), 5.36 (s, 2H), 4.38-4.41 (t, 2H), 3.92 (s, 3H), 3.76-3.72 (t, 2H), 3.16 (s, 3H); ES MS (M+1)=316.

Provenance & Evidence