Sulfuric Acid → 6-(4-chloro-2-pyridin-4-yl-benzyl)-9-hydroxy-2-isopropyl-3,4-dihydro-2H-pyrazino[1,2-c]pyrimidine-1,8-dione

Participants

Reaction Steps

To a stirred solution of 9-benzyloxy-6-(4-chloro-2-pyridin-4-yl-benzyl)-2-isopropyl-3,4-dihydro-2H-pyrazino[1,2-c]pyrimidine-1,8-dione (387) (50 mg, 0.097 mmol) in acetic acid (2 mL), concentrated H2SO4 (0.001 mL, 0.019 mmol) was added and the reaction mixture was stirred for 4 h at room temperature (monitored by LC-MS). From the reaction, volatiles were removed and the residue was quenched with ice c old water (5 mL). Aqueous saturated NaHCO3 was added to adjust the pH up to 8. The quenched mass was extracted with ethyl acetate (2×15 mL). The combined organic part was dried and concentrated and the resulting residue was purified by preparative HPLC to get 6-(4-chloro-2-pyridin-4-yl-benzyl)-9-hydroxy-2-isopropyl-3,4-dihydro-2H-pyrazino[1,2-c]pyrimidine-1,8-dione (388) (14.3 mg, 31.45%) as an off-white solid.

Provenance & Evidence