反应详情

Ethyl α-amino-9H-xanthene-9-acetate hydrochloride (5.33 g, 17 mmol) is combined with 45 mL of absolute ethanol and 27 mL of 1.25 M ethanolic potassium hydroxide solution (2 equivalents). The progress of the reaction is monitored by thin layer chromatography (TLC), silica gel (SiO2), hexane:2-propanol/3:7 with 1% of acetic acid. After 13 hours and an additional two equivalents of the potassium hydroxide solution (in three portions) most of the starting material is consumed. Ethanol is stripped off, the residue is taken up in 100 mL of water, and extracted with diethyl ether. The aqueous portion is acidified with 0.5 N hydrochloric acid (~100 mL) to pH 2 and cooled overnight. A white precipitate is collected by filtration, washed with cold water, diethyl ether, and dried at 50° C./10 mm Hg. This provides 3.18 g of the title compound; mp 264°-269° C. (dec).

1. extractionextracted with diethyl ether
2. temperaturecooled overnight
3. filtrationA white precipitate is collected by filtration
4. washwashed with cold water, diethyl ether
5. customdried at 50° C./10 mm Hg