反应详情

Compound 1a (4.0 g, 12.7 mmol) was dissolved in isopropanol (50 mL), and methylsulfonic acid (1.8 g, 18.5 mmol) was added. The reaction was agitated at room temperature for 5 hrs. The reaction was monitored by TLC (petroleum ether/ethyl acetate=5/1). After the reaction completed, the solvent and excess methylsulfonic acid was removed by evaporation. The mixture was then diluted with water. The pH value was adjusted to 7-8 with saturated NaHCO3 solution. The mixture was extracted by ethyl acetate (30 mL×2). The organic phase was combined, washed with saturated sodium chloride solution, dried over anhydrous sodium sulfate, and then dried by rotary dryer. Column chromatography (petroleum ether/ethyl acetate=7/1) afforded 1.6 g of white solid (compound 1b), yield 55%.

1. customthe solvent and excess methylsulfonic acid was removed by evaporation
2. additionThe mixture was then diluted with water
3. extractionThe mixture was extracted by ethyl acetate (30 mL×2)
4. washwashed with saturated sodium chloride solution
5. dry with materialdried over anhydrous sodium sulfate
6. customdried by rotary dryer