Sulfuric Acid → 6-[1-(4-chlorophenyl)-cyclopentylmethyl]-9-hydroxy-2-(tetrahydro-pyran-4-yl)-3,4-dihydro-2H-pyrazino[1,2-c]pyrimidine-1,8-dione

Participants

Reaction Steps

To a stirred solution of 9-benzyloxy-6-[1-(4-chlorophenyl)-cyclopentylmethyl]-2-(tetrahydro-pyran-4-yl)-3,4-dihydro-2H-pyrazino[1,2-c]pyrimidine-1,8-dione (335) in acetic acid (1 mL), concentrated H2SO4 (0.001 mL, 0.02 mmol) was added and stirred for 4 h at room temperature (monitored by LC-MS). After completion of the reaction, volatiles were removed from the reaction mixture, and the mixture was quenched with ice-cold water (5 mL). Saturated aqueous NaHCO3 (adjusted pH to 8) was added and the quenched mixture was extracted with ethyl acetate (2×15 mL). The combined extracts were dried and concentrated. The resulting residue was washed with 10% dichloromethane in ether to get 6-[1-(4-chlorophenyl)-cyclopentylmethyl]-9-hydroxy-2-(tetrahydro-pyran-4-yl)-3,4-dihydro-2H-pyrazino[1,2-c]pyrimidine-1,8-dione (336) (19 mg, 41%) as an off-white solid.

Provenance & Evidence