反应详情

13.0 g of the compound obtained in Example 1 was dissolved in 260 mL of methanol, and a solution obtained by dissolving 4.84 g of sodium hydroxide in 26 mL of water was added thereto. The resulting solution was refluxed for 4 hours, cooled to room temperature, concentrated under reduced pressure to remove methanol. The resulting aqueous solution was washed with 10 ml of diethyl ether and acidified to pH 2 to 3 using concentrated HCl. The solids thus solidified were filtered, washed with a small amount of cold water and dried at 40° C. to obtain 9.60 g (yield of 85%) of the title compound as a brown solid.

1. customa solution obtained
2. additionwas added
3. temperatureThe resulting solution was refluxed for 4 hours
4. concentrationconcentrated under reduced pressure
5. customto remove methanol
6. washThe resulting aqueous solution was washed with 10 ml of diethyl ether
7. filtrationThe solids thus solidified were filtered
8. washwashed with a small amount of cold water
9. customdried at 40° C.