反应详情

To cold (0° C. ice bath) methanol (200 mL) with stirring was added drop-wise thionyl chloride (12 mL, 164 mmol). The reaction was maintained for 15 minutes, at which time 5-chloro-3-hydroxy-2-methylbenzoic acid (6.5 g, 34.8 mmol) was added. The reaction was allowed to warm to room temperature and maintained overnight. The reaction was evaporated to dryness under vacuum and the residue was purified by silica gel chromatography (Analogix, SF40-150 g, 50 to 100% CH2Cl2 in hexanes). An overlap fraction containing a close faster running impurity was combined and repurified to give more pure product. The combined pure fractions were evaporated to dryness to give methyl 5-chloro-3-hydroxy-2-methylbenzoate (4.52 g, 22.53 mmol, 64.7% yield) as a white solid. 1H NMR (400 MHz, DMSO-d6) δ 10.29 (s, 1H), 7.18 (d, J=2.02 Hz, 1H), 7.01 (d, J=2.27 Hz, 1H), 3.82 (s, 3H), 2.25 (s, 3H). MS(ES) [M+H]+ 201.0.

1. additionwas added
2. temperaturemaintained overnight
3. customThe reaction was evaporated to dryness under vacuum
4. customthe residue was purified by silica gel chromatography (Analogix
5. additionAn overlap fraction containing
6. customa close faster
7. customrepurified
8. customto give more pure product
9. customThe combined pure fractions were evaporated to dryness