反应详情

When a substituted benzaldehyde, preferably 3,4-dimethoxybenzaldehyde, is reacted with the grignard reagent, an alcohol is produced by the well-known grignard synthesis reaction. Preferably, the alcohol formed is 1,4-bis(3,4-dimethoxyphenyl)butane-1-ol. Preferably the grignard reagent is cooled to about 0° C. and 3,4-dimethoxybenzaldehyde in a suitable solvent such as tetrahydrofuran is added over a period of about one hour at a temperature of between about 0° C. and about 3° C. The starting materials should be of high purity; and the reaction should be carried out in a dry, inert atmosphere. The mixture is allowed to warm to room temperature and stirred for a period of between about 8 and about 12 hours. The mixture is then cooled to about 0° C. and treated with saturated ammonium chloride solution at about this temperature. After several more hours at room temperature, product is obtained by filtration and evaporation of the filtrate. Additional product is extracted from the solids with methylene chloride. Some 1,4-bis(3,4-dimethoxyphenyl) 1-butanone may be formed along with the expected alcohol, and this may be converted to the alcohol with a suitable reducing agent such as sodium borohydride. An additional impurity, wherein one of the phenolic methoxy groups has been converted to a hydroxy, may also be present, but where the final product calls for replacement of all phenolic alkoxy groups with hydroxy groups, this impurity may be carried along through ensuing steps and will be converted to the desired end product. Based on these considerations, a maximum yield for the grignard synthesis reaction is obtained by this method.

1. customand the reaction
2. temperatureThe mixture is then cooled to about 0° C.
3. waitAfter several more hours at room temperature
4. customproduct is obtained by filtration and evaporation of the filtrate
5. extractionAdditional product is extracted from the solids with methylene chloride