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

Participants

Reaction Conditions

Reaction Steps

In a sealed tube was placed a stirred solution of 9-benzyloxy-6-(2-bromo-4-chlorobenzyl)-2-isopropyl-3,4-dihydro-2H-pyrazino[1,2-c]pyrimidine-1,8-dione (380) (100 mg, 0.194 mmol) in dioxane (4 mL). Pyridine 4-boronic acid (23.822 mg, 0.194 mmol), and a 1N solution of potassium carbonate [(80.349 mg, 0.581 mmol) in 0.82 mL water] were added at room temperature and the reaction mixture was purged for 30 min with argon. Pd(triphenyl phosphine)4 (22.395 mg, 0.019 mmol) and 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl (15.911 mg, 0.039 mmol) were added to the reaction under argon. The reaction mixture was further degassed for another 10 min and thereafter heated at 80° C. for 4 h (monitored by LC-MS). The reaction mixture was filtered through a pad of celite and the filtrate was diluted with water (5 mL) and extracted with ethyl acetate (2×20 mL). The combined extracts were dried and concentrated. The resulting crude product was purified by column (using amine bound silica gel) to get 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) (51 mg, 51.1%) as an off-white solid.

Provenance & Evidence