6-[1-(4-chlorophenyl)-cyclopentylmethyl]-9-hydroxy-2-isopropyl-3,4-dihydro-2H-pyrazino[1,2-c]pyrimidine-1,8-dione → 9-hydroxy-2-isopropyl-6-(1-phenyl-cyclopentylmethyl)-3,4-dihydro-2H-pyrazino[1,2-c]pyrimidine-1,8-dione

Participants

Reaction Steps

To a stirred solution of 6-[1-(4-chlorophenyl)-cyclopentylmethyl]-9-hydroxy-2-isopropyl-3,4-dihydro-2H-pyrazino[1,2-c]pyrimidine-1,8-dione (32-03) (350 mg, 0.842 mmol) was added 35 mg 10% Pd—C. Hydrogenation was conducted by balloon pressure at room temperature for 9 h. After completion of the reaction, the mixture was filtered over a celite bed, which was washed with methanol, followed by 10% methanol in dichloromethane. The filtrate was concentrated to a pasty mass, which was washed with ether, followed by pentane to get 9-hydroxy-2-isopropyl-6-(1-phenyl-cyclopentylmethyl)-3,4-dihydro-2H-pyrazino[1,2-c]pyrimidine-1,8-dione (32-04) (175 mg, 54.5%) as a yellow solid.

Provenance & Evidence