To a solution of (R)-6-(4-chlorophenyl)-1,4-dimethyl-8-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-5,6-dihydro-4H-benzo[b][1,2,4]triazolo[4,3-d][1,4]diazepine (100 mg, 0.22 mmol) in dioxane/water (11 mL, dioxane/water=10:1) was added 5-Bromo-6-methyl-1H-pyridin-2-one (51 mg, 0.27 mmol), cesium carbonate (145 mg, 0.44 mmol) and [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) (17 mg, 0.022 mmol) under nitrogen atmosphere. The mixture was stirred and heated to reflux overnight. The mixture was cooled down and poured into water (30 mL) and extracted with ethyl acetate (20 ml×3). The combined organic phase was concentrated, and the residue was purified by HPLC (Mobile phase A: water with 0.05% ammonia solution; Mobile phase B: MeCN; column temperature: 30° C., Gradient: 25-55% B, 15 min) to give (R)-5-(6-(4-chlorophenyl)-1,4-dimethyl-5,6-dihydro-4H-benzo[b][1,2,4]triazolo[4,3-d][1,4]diazepin-8-yl)-6-methylpyridin-2(1H)-one as a white solid (16 mg, 17%).
