| 摘要 |
Ethyl apovincaminate of formula (I) is prepd. by (i) esterifying vincamine with ethanol in the presence of alkali metal and formic acid treatment; (ii) treating anhydrous vincamine derived from tabersonine by semi-synthetic method with formic acid, or (iii) saponification of vincamine and vincaminic acid resulting from esterification with diazo ethane. USE/ADVANTAGE - The prod. is useful as cerebral vasodilating agent. The method is new and gives better prod.. In an example, vincamine 10g, derived from tabersonine 12.5g, is suspended in absolute ethanol 400ml. Sodium 0.7g is added and the mixture is refluxed for 20 min. at 150 deg.C. 95% of the ethanol is distilled off and ethyl vincaminate (7.5g) is crystallised out. This is then treated with formic acid to give required prod..
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