Trifluoroacetic acid → 5-(5-(3-Hydroxy-3-methylbut-1-ynyl)-4-(piperidin-4-ylmethylamino)pyridin-2-ylamino)pyrazine-2-carbonitrile

TFA (0.2 mL) was added at room temperature to a solution of tert-butyl 4-((2-(5-cyanopyrazin-2-ylamino)-5-(3-hydroxy-3-methylbut-1-ynyl)pyridin-4-ylamino)methyl)piperidine-1-carboxylate (0.020 g, 0.041 mmol) dissolved in dichloromethane (2 mL). The reaction mixture was stirred for 20 min. Solvent was removed in vacuo and the crude mixture was purified by ion exchange on SCX-II acidic resin (500 mg), eluting with methanol then 2M ammonia-methanol. The basic fractions were combined and solvent was removed in vacuo. The crude product was purified by preparative thin layer chromatography, eluting with methanol/dichloromethane (1/19), to give the title compound as a yellow solid (0.008 g, 50%).