Sodium Carbonate → (R)-4-Methyl-6-phenyl-3,4-dihydro-2H-pyrazino[1,2-a]indol-1-one

Participants

Reaction Conditions

Reaction Steps

A mixture of (R)-6-bromo-4-methyl-3,4-dihydropyrazino[1,2-a]indol-1(2H)-one [CAS No. 396075-75-5] (69.8 mg, 0.25 mmol) and commercially available phenylboronic acid (39.6 mg, 0.325 mmol) in 1,2-dimethoxyethane (1.67 ml) and 2M sodium carbonate solution (416 μl, 832 μmol) was purged with argon in an ultrasonic bath for 5 min. Then triphenylphosphine (13.1 mg, 50.0 μmol) and palladium(II)acetate (5.61 mg, 25.0 μmol) were added at room temperature, and afterwards the reaction mixture was allowed to stir for 2 h at 85° C. The reaction mixture was cooled to room temperature, poured into water (20 ml) and extracted with dichloromethane (2×20 ml). The combined organic layers were washed with brine (1×20 ml), dried (MgSO4) and evaporated. The crude material (70 mg) was purified by flash chromatography on silica gel [dichloromethane-dichloromethane/MeOH 9:1 (20-80%)] and subsequent trituration with diethyl ether (0.5 ml) and heptane (10 ml) to yield the title compound as a grey solid (60 mg, 87%), MS (ISN) m/z=277.2 [(M+H)+], mp 239° C.

Provenance & Evidence