TBTU (102 mg, 0.32 mmol) was added to a stirred solution of 8-(1-(3,5-difluorophenyl)pyrrolidin-2-yl)-2-morpholino-4-oxo-4H-chromene-6-carboxylic acid (105 mg, 0.21 mmol), 4-methylmorpholine (0.070 mL, 0.63 mmol) and 2-(methylamino)ethanol (0.022 mL, 0.28 mmol) dissolved in NMP (1.5 mL). The resulting solution was stirred at room temperature for 16 h then purified by preparative HPLC. The fractions were evaporated to dryness and triturated in diethyl ether to afford a solid. This material was collected by filtration, washed with diethyl ether and dried under vacuum at 50° C. to afford 8-(1-(3,5-difluorophenyl)pyrrolidin-2-yl)-N-(2-hydroxyethyl)-N-methyl-2-morpholino-4-oxo-4H-chromene-6-carboxamide (77 mg, 71%) as a white solid.
