Hydrochloric Acid → 6-[1-(2,5-dichlorophenyl)-cyclopentylmethyl]-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-[1-(2,5-dichlorophenyl)-cyclopentylmethyl]-2-isopropyl-3,4-dihydro-2H-pyrazino[1,2-c]pyrimidine-1,8-dione (208) (500 mg, 0.93 mmol) in methanol (5.5 mL) was added concentrated HCl (4 mL) and the mixture was stirred for 20 h. Silica thin layer chromatography was performed (100% ethyl acetate, Rf=0.3). Methanol was removed, water was added, the mixture was basified (pH˜8) with solid NaHCO3, extracted with ethyl acetate (3×20 mL), and the organic part was dried and concentrated. The crude product was purified by preparative HPLC purification to get 6-[1-(2,5-dichlorophenyl)-cyclopentylmethyl]-9-hydroxy-2-isopropyl-3,4-dihydro-2H-pyrazino[1,2-c]pyrimidine-1,8-dione (209) (32 mg, 11.34%) as a light brown solid.

Provenance & Evidence