6-Chloro-4-methyl-1-trityl-1H-pyrazolo[4,3-c]pyridin-3 (2H)-one (Intermediate 4B; 300 mg, 0.704 mmol), (R)-1-(1-phenylethyl)urea (139 mg, 0.845 mmol), palladium(II) acetate (31.6 mg, 0.141 mmol), 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (122 mg, 0.211 mmol), and cesium carbonate (574 mg, 1.761 mmol) were taken up in dioxane (10.0 mL) in a 25 mL microwave vial. The vial was evacuated and back-filled with N2 (×3) then the reaction mixture was heated to 80° C. for 24 h. The reaction mixture was diluted with DCM, filtered through celite, and the filtrate was washed with water then brine. The organic layer was dried over sodium sulfate, filtered, concentrated in vacuo, and purified by flash chromatography (20-80% EtOAc/Hexanes) to give (R)-1-(4-methyl-3-oxo-1-trityl-2,3-dihydro-1H-pyrazolo[4,3-c]pyridin-6-yl)-3-(1-phenylethyl)urea. MS ESI calc'd. For C35H31N5O2 [M+1]+ 554. found 554.
