Water → (R)-[1-(2-cyano-ethyl)-4,5,6,7-tetrahydro-1H-indazol-4-yl]-carbamic acid benzyl ester

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Reaction Conditions

Reaction Steps

To a solution of methanesulfonic acid 2((R)-4-benzyloxycarbonylamino-4,5,6,7-tetrahydroindazol-1-yl)-ethyl ester (850 mg, 2.16 mmol) in dimethyl sulfoxide (20 mL) was added sodium cyanide (540 mg, 10.8 mmol). The mixture was stirred at 55° C. for 4 hours. After cooling, to the mixture was added water, and the aqueous layer was extracted with ethyl acetate (20 mL×4). The combined organic layers were dried over sodium sulfate, filtered and then concentrated in vacuo. The residue was purified by flash column chromatography (10% methanol in dichloromethane) to afford (R)-[1-(2-cyano-ethyl)-4,5,6,7-tetrahydro-1H-indazol-4-yl]-carbamic acid benzyl ester (600 mg, 85%) as a white solid. MS calcd. for C18H20N4O2 324, obsd. (ESI+) [(M+H)+] 325.

Provenance & Evidence