反应详情

The hydrochloride of L-tryptophan methyl ester (1.01 g) was stirred vigorously for 15 minutes with 1,2-dichloroethane (20 ml) and saturated NaHCO3 solution (20 ml) and the aqueous phase was immediately extracted with 1,2-dichloroethane (2×20 ml). After drying with Na2SO4, the organic phase was concentrated to 40 ml, and 4-dimethylamino-4-phenylcyclohexanone (893 mg, 4 mmol.) was added thereto under argon. Glacial acetic acid (0.228 ml, 4 mmol.) and Na2SO4 (2 g) were added to the clear solution. After a reaction time of 15 minutes, NaBH(OAc)3 (1.2 g) was added to the reaction mixture, and stirring was carried out for 4 days at room temperature. For working up, saturated NaHCO3 solution (40 ml) was added and stirring was carried out for 15 minutes. The aqueous phase was extracted with dichloromethane (2×20 ml). The combined organic phases were dried and then concentrated, yielding a light-brown oil. Purification by column chromatography was carried out with ethyl acetate and methanol. The nonpolar diastereomer (918 mg; m.p. 108-112° C.) was dissolved in 2-butanone (15 ml) and converted with chlorotrimethylsilane (0.4 ml) into the corresponding dihydrochloride (white solid; 326 mg; m.p. 197-202° C.).

1. extractionthe aqueous phase was immediately extracted with 1,2-dichloroethane (2×20 ml)
2. dry with materialAfter drying with Na2SO4
3. additionwas added
4. stirringstirring
5. waitwas carried out for 15 minutes
6. extractionThe aqueous phase was extracted with dichloromethane (2×20 ml)
7. customThe combined organic phases were dried
8. concentrationconcentrated
9. customyielding a light-brown oil
10. customPurification by column chromatography
11. dissolutionThe nonpolar diastereomer (918 mg; m.p. 108-112° C.) was dissolved in 2-butanone (15 ml)