西他沙星中间体氮杂螺环的合成工艺改进

Improvement on the Synthetic Method of Sitafloxacin Intermediate Aza Spiro Alkane

以乙酰乙酸乙酯为原料合成氮杂螺环(8),对其合成工艺中的三元环化反应进行了改进,采用γ-环糊精作相转移催化剂,使得该步反应时间缩短至5 h,收率提高至96.8%。考察该反应条件,得出最佳的工艺条件:γ-环糊精作相转移催化剂,n(γ-环糊精)∶n(4)=0.1,最佳反应温度70℃,反应时间5 h。回收γ-环糊精,并讨论其再利用效果。改进后的工艺更加经济高效。

The aza spiro alkane （8） has been prepared from ethylacetoacetate. The reaction of cyclization in the process of aza spiro alkane has been improved. y-CD was used as the phase transfer catalyst making the reaction time shortened to 5 h and the yield up to 96.8 %. Comparing to the reaction conditions, optimal conditions were that： y-CD was used as phase transfer catalyst, n（y-CD） ： n（4）-0.1, the best reaction temperature was 70 ℃ reaction time was 6 h. The effect of recycled 3,-CD on cyclization was discussed. The improved method was more economical and efficient.