反应详情

A mixture of 2-(4-bromo-2-dimethylcarbamoylsulfanyl-benzoyl)-malonic acid dimethyl ester (11.2 g, 26.79 mmol) in 0.5 M NaOMe/MeOH solution (214 mL) was heated to reflux for 6 h. After cooling overnight, the precipitated solid was collected by filtration and rinsed with MeOH followed by ether. The solid was dried in vacuo to provide 7-bromo-4-hydroxy-2-oxo-2H-thiochromene-3-carboxylic acid methyl ester (5.37 g) as a sodium salt. 1H NMR (200 MHz, DMSO-d6): δ (ppm)=7.98 (d, J=8.5 Hz, 1H), 7.50 (d, J=1.9 Hz, 1H), 7.38 (dd, J=8.5, 1.8 Hz, 1H), 3.56 (s, 3H).

1. temperaturewas heated
2. temperatureto reflux for 6 h
3. temperatureAfter cooling overnight
4. filtrationthe precipitated solid was collected by filtration
5. washrinsed with MeOH
6. customThe solid was dried in vacuo