反应详情

Methanesulfonic acid (18 mL, 0.28 mol) was added to a stirred solution of 6-hydroxy-1-naphthoic acid (262 g, 1.39 mol) in methanol (1 L) under N2 and the reaction mixture was heated at reflux for 18 h. The reaction mixture was cooled to room temperature and concentrated to give a purple solid. The solid was dissolved in ethyl acetate (1 L), washed with water (3×300 mL), saturated sodium bicarbonate solution (2×300 mL), water (500 mL), brine (300 mL) and then dried over anhydrous sodium sulfate. The resulting solution was filtered and concentrated to give 271 g of the product as a pink solid. 1H NMR (400 MHz, d6-DMSO): δ 9.94 (s, 1H), 8.58 (m, 1H), 7.93 (d, J=8 Hz, 1H), 7.86 (d, J=7.0 Hz, 1H), 7.44 (t, J=8 Hz, 1H), 7.22-7.19 (m, 2H), 3.88 (s, 3H). ESI-LCMS m/z 203 (M+H)+.

1. temperaturethe reaction mixture was heated
2. temperatureat reflux for 18 h
3. concentrationconcentrated
4. customto give a purple solid
5. washwashed with water (3×300 mL), saturated sodium bicarbonate solution (2×300 mL), water (500 mL), brine (300 mL)
6. dry with materialdried over anhydrous sodium sulfate
7. filtrationThe resulting solution was filtered
8. concentrationconcentrated