反应详情

To a solution of 6.4 g (17.8 mmol) of O-(9-phenyl-9H-fluoren-9-yl)-L-serine methyl ester from step 2 in methanol (20 mL) was added 20% sodium hydroxide (10 mL) and the mixture stirred at room temperature for 1 h. Most of the methanol was evaporated under vacuo, the residue suspended in water (200 mL) and extracted with diethyl ether (2×50 mL). The alkaline aqueous phase was added dropwise into 20% acetic acid (30 mL) with stirring and cooling with an ice bath, the white precipitate was filtered, washed with water and dried in vacuo over P2O5 to give 5.3 g (yield 90%) of O-(9-phenyl-9H-fluoren-9-yl)-L-serine as a white powder. 13C NMR (DMSO-d6, 75 MHz) δ: 167.0, 146.4, 146.1, 143.3, 140.3, 140.0, 129.4, 129.2, 128.4, 128.2, 128.0, 127.2, 125.6, 125.5, 125.1, 120.5, 120.4, 88.4, 63.2, 54.8.

1. customMost of the methanol was evaporated under vacuo
2. extractionextracted with diethyl ether (2×50 mL)
3. additionThe alkaline aqueous phase was added dropwise into 20% acetic acid (30 mL)
4. stirringwith stirring
5. temperaturecooling with an ice bath
6. filtrationthe white precipitate was filtered
7. washwashed with water
8. dry with materialdried in vacuo over P2O5