反应详情

To a solution of 0.39 g (1 mmol) N,N-Dimethyl--O--(9-phenyl-9H-fluoren-9-yl)-L-serine methyl ester from Step 1 in methanol (4 mL) was added 20% sodium hydroxide (2 mL) and the mixture stirred at room temperature for 1 h. Most of the methanol was evaporated in vacuo, the residue suspended in water (10 mL) and extracted with diethyl ether (2×2 mL). The alkaline aqueous phase was acidified with 20% acetic acid by cooling with an ice bath, the white precipitate was filtered, washed with water and dried in vacuo over P2O5 to give 0.314 g (yield 84%) N,N-dimethyl-O-(9-phenyl-9H-fluoren-9-yl)-L-serine as a white powder. 1H NMR (CD3OD, 300 MHz) δ: 7.87 (br s, 2H), 7.70-7.10 (m, 11H), 3.70-3.45 (m, 3H), 2.95 (s, 6H).

1. customMost of the methanol was evaporated in vacuo
2. extractionextracted with diethyl ether (2×2 mL)
3. temperatureby cooling with an ice bath
4. filtrationthe white precipitate was filtered
5. washwashed with water
6. dry with materialdried in vacuo over P2O5