Trifluoroacetic acid → 4-amino-N,N-dicyclopropyl-6-ethyl-1-methyl-1,6-dihydroimidazo[4,5-d]pyrrolo[2,3-b]pyridine-7-carboxamide

To a solution of tert-butyl 7-(dicyclopropylcarbamoyl)-6-ethyl-1-methyl-1,6-dihydroimidazo[4,5-d]pyrrolo[2,3-b]pyridin-4-yl(2,4-dimethoxybenzyl)carbamate (example 1I, 2.66 g, 4.51 mmol) in dichloromethane (33.8 mL) was added TFA (11.28 mL). The reaction mixture was stirred at rt 45 min and was concentrated in vacuo. The crude residue was partitioned between ethyl acetate and saturated aqueous sodium bicarbonate. The aqueous layer was extracted with ethyl acetate (2×) and the combined organics were dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The crude solid was purified by flash chromatography using an Isco 40 g column eluting with 4-10% MeOH/CH2Cl2 to yield 4-amino-N,N-dicyclopropyl-6-ethyl-1-methyl-1,6-dihydroimidazo[4,5-d]pyrrolo[2,3-b]pyridine-7-carboxamide (1.2 g, 3.55 mmol, 79% yield) as a pale yellow solid.