左氧氟沙星半水合物的制备工艺

Preparation Process of Levofloxacin Hemihydrate

本研究对左氧氟沙星半水合物(1)的合成工艺进行了改进。将硫酸钠十结晶水合物作为制备1的定量水分的来源,在乙醇中逐步缓慢加热,于33~35℃保温1 h,再升温至65~70℃,保温2 h,促使硫酸钠十结晶水合物释放出所含水分,从而保证左氧氟沙星专一性地生成1。改进后的工艺解决了文献中高沸点溶剂在1中残余量大、低沸点溶剂用量大的问题,更方便可靠。

An improved synthetic process of levofloxacin hemihydrate(1)was reported.Sodium sulfate decahydrate was used as the source of quantitative water for the preparation of 1,and the reaction system was slowly and gradually heated in ethanol,keeping at 33-35℃for 1 h,then heated to 65-70℃,keeping for 2 h,to promote the release of water from the sodium hydrate decahydrate,which ensured that 1 was obtained specifically from levofloxacin.The improved process solved the problems of large residual amounts of high-boiling solvents in target product and large amounts of low-boiling solvents used in preparation of 1,which was more convenient and reliable.