To a mixture of formic acid. (0.38 mL, 9.6 mmol), EDC (1.84 g, 9.6 mmol) and HOBt (0.2 g, 1.3 mmol) in CH2Cl2 (25 mL) under nitrogen were added compound C-(3-chloropyrazin-2-yl)-C-(4-phenoxyphenyl)-methylamine (2.0 g, 6.4 mmol), followed by DIEA (2.2 mL, 12.8 mmol). The mixture was stirred for 16 h at rt. TLC (EtOAc/CH2Cl2, 1:1) showed no starting material. The reaction mixture was diluted with CH2Cl2 (75 mL), washed with water (3×50 mL) and dried (Na2SO4). Evaporation of solvent gave desired product, which was used for next step without any further purification. Yield: 1.85 g (84%). 1H NMR (CDCl3, 300 MHz) δ 6.61 (d, J=6.8 Hz, 1H), 6.70-6.99 (m, 4H), 7.16 (t, J=7.2 Hz, 1H), 7.27-7.32 (m, 4H), 8.29 (s, 1H), 8.38 (d, J=2.4 Hz, 1H), 8.61 (d, J=2.4 Hz, 1H).
