4-(9-Cyclopentyl-5-methyl-6-oxo-6,7,8,9-tetrahydro-5H-pyrimido[4,5-b][1,4]diazepin-2-ylamino)-3-methoxybenzoic acid (Intermediate 8) (0.49 g, 1.2 mmol, 1 eq), TBTU (0.42 g, 1.3 mmol, 1.1 eq) and DIPEA (0.40 mL, 2.4 mmol, 2 eq) were stirred together in DCM (25 mL) for 30 min before addition of 4-amino-1-BOC-piperidine (0.29 g, 1.4 mmol, 1.2 eq). The RM was stirred at rt for 20 hours before diluting with DCM (30 mL) and washing sequentially with water (2×15 mL), 50% saturated aqueous sodium hydrogen carbonate (1×20 mL), saturated aqueous potassium carbonate (1×20 mL) and saturated brine (1×20 mL). Concentrated in vacuo to isolate 4-(9-cyclopentyl-5-methyl-6-oxo-6,7,8,9-tetrahydro-5H-pyrimido[4,5-b][1,4]diazepin-2-ylamino)-3-methoxy-N-(1-BOC-piperidin-4-yl)benzamide that was used without further purification (0.71 g). Rt=3.58 min (Analytical—1).
