A mixture of 2-Cyanoacetamide (120 mg, 1.5 mmol) and triethyloxonium tetrafluoroborate (270 mg, 1.4 mmol) in THF (1.1 mL) was stirred at room temperature for 2 h. The solvent was removed and the residue dissolved in ethanol (0.5 mL) and added to a suspension of tert-butyl ({trans-4-[(6-aminothieno[3,2-b]pyridin-7-yl)amino]cyclohexyl}methyl)carbamate (150 mg, 0.40 mmol) in ethanol (1.7 mL). The mixture was stirred at 85° C. for 2 h. The solid was filtered and the filtrate was concentrated and purified on flash chromatography (0-10% methanol/dichloromethane) to give the desired product (0.12 g, 71%). LCMS calculated for C22H28N5O2S (M+H)+: m/z=426.2. Found: 426.0.
