Preparation
A method for preparing Vincamine, the method comprising the following steps:
1) Preparation of taponin: Taponin hydrochloride is freed in petroleum ether using concentrated ammonia, and then an acid salt solution is added to remove the remaining ammonia. After the reaction is completed, the aqueous layer is extracted with petroleum ether, the organic phases are combined, the organic phases are dried with a drying agent, filtered, and the filtrate is distilled under reduced pressure to obtain taponin;
2) Preparation of Vincamine: Taponin obtained in step (1) is dissolved in an organic solvent, Pd/C is added under stirring, and the reaction is carried out under a hydrogen atmosphere and normal pressure at a certain temperature. The reaction endpoint is monitored by TLC, filtered, and the filtrate is distilled under reduced pressure to obtain Vincamine;
3) Preparation of monoperoxymaleic acid: Maleic anhydride is dissolved in N,N-dimethylformamide, 30% hydrogen peroxide is added dropwise, and the reaction is carried out after the addition is complete. After the reaction is completed, the temperature is lowered, and the solution is diluted with cold methanol for later use;
4) Preparation of Vincamine: The Vincamine obtained in step (2) was dissolved in methanol, cooled, and a certain amount of monoperoxymaleic acid obtained in step (3) was added dropwise. After the oxidation reaction was carried out for a period of time, a certain amount of monoperoxymaleic acid was added dropwise. After the addition was completed, the oxidation reaction was continued for a period of time. After the reaction was completed, a reducing agent solution was added dropwise until the starch KI test paper no longer changed color. The temperature was raised to carry out the rearrangement reaction. After the reaction was completed, the temperature was lowered to 20-30℃, and a certain amount of water and concentrated ammonia were added to adjust the pH to a certain range. The temperature was lowered to crystallize, filtered, and the filter cake was washed with methanol and water. Then, it was pulped with water at a certain temperature, filtered, and the filter cake was dried under reduced pressure to obtain Vincamine.
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