反应详情

A solution of 32 g (0.21 mol) of 4'-methoxyacetophenone and 165 g (2.1 mol) of ammonium acetate in 450 ml of methanol is combined with 13.5 g (0.21 mol) of sodium cyanoborohydride, which is added in batches thereto at ambient temperature, with stirring. After a further 20 hours, ice is added and the mixture is acidified with hydrochloric acid (conc. HCl H2O=1/1) until the pH is 2. The acidic solution is extracted with dichloromethane. The aqueous phase is then mixed with conc. ammonia, with cooling, until a clearly alkaline reaction occurs and then extracted exhaustively with dichloromethane. The combined dichloromethane extracts are dried over sodium sulphate and evaporated to dryness in vacuo. The crude 2-(4-methoxyphenyl)-1-methylethylamine thus obtained is purified by column chromatography over silica gel (eluant: dichloro-methane/methanol=20/1) to remove any by-products. A colorless oil is obtained which can be used for reaction without any further purification.

1. additionis added in batches
2. additionice is added
3. extractionThe acidic solution is extracted with dichloromethane
4. additionThe aqueous phase is then mixed with conc. ammonia
5. temperaturewith cooling, until a clearly alkaline reaction
6. extractionextracted exhaustively with dichloromethane
7. dry with materialThe combined dichloromethane extracts are dried over sodium sulphate
8. customevaporated to dryness in vacuo