Sodium hydride → 2-(cyclopropylmethyl)-8-(1-isopropylpiperidin-4-yloxy)-3,4-dihydropyrazino[1,2-a]indol-1(2H)-one

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Reaction Steps

To the solution of 0.15 g (0.46 mmol) 8-(1-isopropyl-piperidin-4-yloxy)-3,4-dihydro-2H-pyrazino[1,2-a]indol-1-one (example 1) in 3 mL N,N-dimethylformamide, 24 mg (0.55 mmol, 55% dispersion in mineral oil) sodium hydride was added. After 30 min., 1-(bromomethyl)cyclopropane was added and the mixture was stirred until completion of the reaction as indicated by TLC (2 h). The reaction mixture was poured on 10% aqueous ammonium chloride solution and was extracted three times with ethyl acetate. The organic layers were washed with water and brine, dried over magnesium sulfate, filtered and evaporated. The residue was purified by flash column chromatography on silica gel with dichloromethane:methanol:ammonia (9:1:0.1 v/v) to give the desired compound as a white solid (38%).

Provenance & Evidence