反应详情

To a solution of methyl 3-amino-5-chloro-2-ethylbenzoate (1.5 g, 7.02 mmol) in 1,2-Dichloroethane (28 ml) at room temperature and under nitrogen was added oxan-4-one (1.3 ml, 14.04 mmol) followed by acetic acid (2.41 ml, 42.12 mmol). This solution was stirred for 5 minutes before the addition of sodium triacetoxyborohydride (4.46 g, 21.06 mmol) at room temperature. After stirring for 20 hours, deionized water (28 ml) was added and the mixture was neutralized with solid NaHCO3. The phases were separated and the aqueous layer was extracted with EtOAc (2×28 ml). The combined organic extracts were dried over MgSO4, filtered and concentrated under reduced pressure. The residue was purified by FCC (50 g silica, Isolute cartridge, gradient of eluents; 95:5 Heptane:EtOAc to 8:2 Heptane:EtOAc) to give 1.76 g (84%, 50% corrected yields) of methyl 5-chloro-2-ethyl-3-[(oxan-4-yl)amino]benzoate as a white solid. Product contains ˜25% ethyl ester. The material was taken through the next step without further purification. LC-MS 60%, 2.27 min (3 minute LC-MS method), m/z=298.0/300.0, 1H NMR (500 MHz, Chloroform-d) δ ppm 7.07 (d, J=2.0 Hz, 1H), 6.71 (d, J=1.9 Hz, 1H), 4.01 (dt, J=11.8, 3.4 Hz, 2H), 3.87 (s, 3H), 3.82-3.76 (m, 1H), 3.64-3.47 (m, 3H), 2.79-2.63 (m, 2H), 2.06 (d, J=13.2 Hz, 2H), 1.55-1.46 (m, 2H), 1.18 (t, J=7.5 Hz, 3H).

1. customThe phases were separated
2. extractionthe aqueous layer was extracted with EtOAc (2×28 ml)
3. dry with materialThe combined organic extracts were dried over MgSO4
4. filtrationfiltered
5. concentrationconcentrated under reduced pressure
6. customThe residue was purified by FCC (50 g silica, Isolute cartridge, gradient of eluents; 95:5 Heptane:EtOAc to 8:2 Heptane:EtOAc)