反应详情

Methyl 3-(2-methoxyethoxy)-2-methyl-4-(methylsulfonyl)benzoate (26 g) was dissolved in methanol (200 mL), and a 20% NaOH aqueous solution (50 mL) was added at room temperature. After stirring for one hour, methanol was distilled off under reduced pressure. To the residue, 2N hydrochloric acid (100 mL) was added, followed by extraction with ethyl acetate (500 mL). The organic layer was washed with saturated brine and dried over anhydrous sodium sulfate, and then, the solvent was distilled off under reduced pressure. To the residue, a mixed solvent (ethyl acetate:hexane=1:1, 50 mL) was added, and the mixture was left to stand at 5° C. for 12 hours. The obtained crystals were collected by filtration to obtain 3-(2-methoxyethoxy)-2-methyl-4-(methylsulfonyl)benzoic acid (19.5 g).

1. distillationmethanol was distilled off under reduced pressure
2. additionTo the residue, 2N hydrochloric acid (100 mL) was added
3. extractionfollowed by extraction with ethyl acetate (500 mL)
4. washThe organic layer was washed with saturated brine
5. dry with materialdried over anhydrous sodium sulfate
6. distillationthe solvent was distilled off under reduced pressure
7. additionTo the residue, a mixed solvent (ethyl acetate:hexane=1:1, 50 mL) was added
8. waitthe mixture was left
9. waitto stand at 5° C. for 12 hours
10. filtrationThe obtained crystals were collected by filtration