Concentrated hydrochloric acid (52 μl) was added to a mixture of (R)-2-chloro-9-(3,3-difluorocyclopentyl)-5,7,7-trimethyl-8,9-dihydro-5H-pyrimido[4,5-b][1,4]diazepin-6(7H)-one (100 mg, 0.29 mmol) and 4-amino-N-cyclopropyl-3-methoxybenzamide (90 mg, 0.44 mmol) in ethanol (1.4 mL) and water (5.2 mL). The reaction mixture was heated to 85° C. and stirred for 48 hours. The reaction mixture was concentrated in vacuo. The residue was dissolved in ethyl acetate, washed with an aqueous saturated solution of sodium bicarbonate and brine. The organic layer was dried over magnesium sulfate and concentrated in vacuo. The residue was purified on silica gel by flash column chromatography to afford the title compound as a white solid (83 mg, 56% yield).
