反应详情

To a flask containing trifluoromethanesulfonic acid (40 mL), 2-(4-chloro-benzylidene)-3-methyl-succinic acid (14.0 g) was added in portions. After being stirred at room temperature for 18 hours, the resulting mixture was poured onto ice-water, and stirred for 15 minutes. The formed precipitate was collected by filtration, and dissolved in ethyl acetate (150 mL). The solution was dried over sodium sulfate, and concentrated in vacuo. The residue was precipitated from ethyl acetate/petroleum ether (1:10) to afford 6-chloro-4-hydroxy-3-methyl-naphthalene-2-carboxylic acid (12.7 g, 97.6%) as a pink solid.

1. additionwas added in portions
2. additionthe resulting mixture was poured onto ice-water
3. stirringstirred for 15 minutes
4. filtrationThe formed precipitate was collected by filtration
5. dissolutiondissolved in ethyl acetate (150 mL)
6. dry with materialThe solution was dried over sodium sulfate
7. concentrationconcentrated in vacuo
8. customThe residue was precipitated from ethyl acetate/petroleum ether (1:10)