To a mixture of methyl 4-(3-amino-6-(piperidin-3-yl)pyrazin-2-yl)-2-fluorobenzoate (55 mg, 0.166 mmol) (for synthesis, see example 34, Step 7) in DCM (3 mL) in ice bath was added DIEA (0.116 mL, 0.666 mmol) followed by acetyl chloride (0.012 mL, 0.166 mmol). The reaction mixture was stirred at 0° C. for 30 min. The reaction mixture was partitioned between DCM and water. The DCM layer was separated, washed with brine, dried over sodium sulfate, filtered and evaporated. The residue was proceeded to next step without purification (50 mg, 81%). LCMS (m/z): 373.3 (MH+), 0.666 min.
