假麻黄碱转变为麻黄碱(Ⅰ)
STUDY ON CONVERSION OF L(+)-Ψ-EPHEDRINE INTO L(-)-EPHEDRINE(Ⅰ)
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摘要: L(+)-ψ-麻黄鹼經下列步驟轉变为L(-)-盐酸麻黄鹼:将L(+)-ψ-麻黄鹼乙酰化得N-乙酰化合物,然后在冰醋酸中使成5%溶液,不加任何物質廻流1.5小时立即回收醋酸后,用10%氫氧化鈉进行水解,再变为盐酸盐即得、以L(+)-N-乙酰-ψ-麻黄鹼为基础計算收得率約为81-85%.L(-)-麻黄鹼在同样情况下只有約24%轉化为盐酸-ψ-麻黄鹼.Abstract: L(-)-Ephedrine hydrochloride was obtained from L(+)-Ψ-ephedrine by the following steps: L(+)-N-acetyl-Ψ-ephedrine was first prepared by acetylation of L(+)-Ψ-epbedrine, the product was then dissolved in glacial acetic acid to form a 5% solution and refluxed for one and one half hour. The acetic acid was re- covered immediately from the mixture. The product was hydrolyzed with 10% NaOH and finally converted to its hydrochloride. The yield was about 81-85% of the theoretical based on the L(+)-N-acetyl-Ψ-ephedrine. Under the same conditions only about 24% L(-)-ephedrine could be converted to L(+)-Ψ-ephedrine.
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