| 摘要 |
PURPOSE:To produce the titled compound having cerebral vasodilating action and useful as a remedy for senile diseases, etc., in high yield without using an acid, by the thermal dehydration of a vincamine compound at a specific temperature in the presence of an N,N-dialkyl-substituted amide compound. CONSTITUTION:The objective compound of formula II can be produced by heating the vincamine compound of formula I (R is 1-5C alkyl) at 150-220 deg.C, preferably 155-190 deg.C for 2-9hr in the presence of an N,N-dialkyl-substituted amide compound (e.g. DMF, N-methyl-2-pyrrolidone, etc.) to effect the dehydration of the vincamine compound.
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