510 mg (3.31 mmol) 6-methoxy-2-pyridinecarboxylic acid was stirred with 1.17 g (3.31 mmol) TBTU and 1.50 mL (8.72 mmol) DIPEA in 10 mL DCM at RT. After 10 min, 1.20 g (3.31 mmol) 2,2-dimethyl-piperazine-1-carboxylic acid benzyl ester trifluoroacetate was added and the reaction mixture was stirred at RT for 2 h. Then the reaction mixture was washed with saturated aqueous NaHCO3 solution. The combined organic phases were dried over sodium sulfate, filtered and concentrated in vacuo. The crude material was purified by flash chromatography (PE/EtOAc=9/1→1/2).
