Sodium triacetoxyborohydride (20.66 mg, 0.097 mmol) was added to a solution of 2-((2-chloro-5-cyano-3-(hexahydro-1H-pyrrolo[3,2-c]pyridin-5(6H)-yl)phenyl)amino)-4-(cyclopropyl(4-methoxybenzyl)amino)imidazo[2,1-f][1,2,4]triazine-7-carbonitrile (Example 442F, 29 mg, 0.049 mmol), paraformaldehyde (14.63 mg, 0.487 mmol) and acetic acid (5.58 μl, 0.097 mmol) in dichloromethane (2 mL) and the reaction mixture was stirred at room temperature for 5 hours. More paraformaldehyde (14.63 mg, 0.487 mmol) and sodium triacetoxyborohydride (20.66 mg, 0.097 mmol) were added and stirring continued overnight. The reaction mixture was diluted with dichloromethane and washed with saturated sodium bicarbonate. The aqueous layer was extracted with dichloromethane two more times. The combined organic layers were dried over magnesium sulfate, filtered and concentrated in vacuo, the crude product was purified by flash chromatography on silica gel using an automated ISCO system (80 g column, eluting with 5-30% ethyl acetate/hexanes). 2-((2-chloro-5-cyano-3-(1-methylhexahydro-1H-pyrrolo[3,2-c]pyridin-5(6H)-yl)phenyl)amino)-4-(cyclopropyl(4-methoxybenzyl)amino)imidazo[2,1-f][1,2,4]triazine-7-carbonitrile (27 mg) was obtained as a white solid.
