A mixture of (2R)-2-hydroxypropanamide (25.8 mg, 0.290 mmol) and triethyloxonium tetrafluoroborate (51.9 mg, 0.273 mmol) in tetrahydrofuran (0.40 mL) was stirred at room temperature for 1 h. After evaporated to dry under reduced pressure, the clear oil was mixed with ethanol (0.20 mL, 3.4 mmol) and added to a solution of 1-{trans-4-[(6-aminothieno[3,2-b]pyridin-7-yl)amino]cyclohexyl}-N-methylmethanesulfonamide (32 mg, 0.090 mmol) in ethanol (0.60 mL) in a microwave vial. The mixture was then heated at 80° C. for 1 h. The mixture was concentrated under reduced pressure. The resultant residue was purified using prep-LCMS (XBridge C18 column, eluting with a gradient of acetonitrile/water containing 0.1% ammonium hydroxide, at flow rate of 30 mL/min) to give the desired product (9.8 mg, 26%). LCMS calculated for C18H25N4O3S2 (M+H)+: m/z=409.1. Found: 409.1.
