Lithium Hydroxide → 6-(7-cyclopentyl-6-(dimethylcarbamoyl)-7H-pyrrolo[2,3-d]pyrimidin-2-ylamino)nicotinic acid

To a suspension of methyl 6-(7-cyclopentyl-6-(dimethylcarbamoyl)-7H-pyrrolo[2,3-d]pyrimidin-2-ylamino)nicotinate (2.0 g, 4.9 mmol) in THF (6 mL) was added 1M LiOH (aq) (6 mL, 1.2 equiv) and the slurry stirred at 45° C. for 12 hours (the slurry became clear). After cooling to room temperature, the THF was evaporated and the reaction mixture was treated with 1N HCl until pH=1-2. The resulting precipitate was filtered and the filtrate extracted with 20% Isopropanol/CH2Cl2 (3×100 mL), the combined organic layers dried, filtered, and concentrated to a tan solid. The tan solid was triturated in acetone giving 6-(7-cyclopentyl-6-(dimethylcarbamoyl)-7H-pyrrolo[2,3-d]pyrimidin-2-ylamino) nicotinic acid as the desired product as a tan solid (1.56 g, 73% yield) which was used without further purification.