反应详情

A mixture of 6-cyclobutoxy-pyridin-3-ylamine (4.41 g, assume 25 mmol), as prepared in the previous step, and CaCO3 (3.25 g, 32.5 mmol) (10 micron powder) was treated with a homogeneous solution of 4-nitrophenyl chloroformate (5.54 g, 27.5 mmol) in toluene (28 mL) in one portion at rt, and was stirred at “rt” (reaction warmed spontaneously) for 2 h. The reaction mixture was then directly loaded onto a flash silica column (95:5 DCM/MeOH→9:1 DCM/MeOH) to afford 5.65 g of material, which was further purified by trituration with hot toluene (1×200 mL) to provide the title compound (4.45 g, 54%). 1H NMR (400 MHz, CDCl3) δ 8.28 (m, 2H), 8.12 (d, 1H), 7.81 (m, 1H), 7.39 (m, 2H), 6.85 (br s, 1H), 6.72 (d, 1H), 5.14 (m, 1H), 2.45 (m, 2H), 2.13 (m, 2H), 1.84 (m, 1H), 1.68 (m, 1H). LC-MS (ESI): calcd mass 329.1, found 330.1 (MH+).

1. customreaction
2. temperaturewarmed spontaneously) for 2 h