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国內文献有很多关于d-伪麻黄硷转化成l-麻黄硷的試驗方法,如用氢氧化鋇、氯比亞碸,五氯化磷、溴氢酸或鹽酸等各种試剂进行轉化。根据目前国內的情况,采用鹽酸轉化較为合适,因成本低廉,較易供应。但文献报导用鹽酸处理时,酸用量大,时間長。于d-伪麻黄硷小加入25%1∶10倍量鹽酸,加溫,廻流24—72小时,然后用苛性鈉中和,再用有机溶媒抽提数次,加草酸析出結晶,再置換成麻黄硷鹽酸鹽。
There are many domestic literatures on the conversion of d-pseudoephedrine into l-ephedrine, for example, conversion with various reagents such as cesium hydroxide, chloramazine, phosphorus pentachloride, hydrobromic acid or hydrochloric acid. According to the current domestic situation, hydrochloric acid conversion is more appropriate because of its low cost and easier supply. However, in the literature, it is reported that the amount of acid is large and takes a long time when it is treated with hydrochloric acid. For d-pseudoephedrine, add 25% 1∶10 times the amount of hydrochloric acid, warm it, turbulent 24-72 hours, then neutralize with caustic soda, then use organic solvent extraction several times, add oxalic acid to precipitate crystals, and then replace Astragalus hydrochloride hydrochloride.