DL-Ephedrine → Ephedrine

Participants

Reaction Steps

In a 5 liter flask containing ethanol (3.4 liters) is introduced 1-ephedrine (143.2 g.; 0.868 mole). Racemic 8-fluorodibenzo[b,f]thiepin-3-carboxylic acid-5-oxide (250 g.; 0.868 mole) is added rapidly to this solution and brought to reflux. After the addition, the reflux is continued until complete solution is obtained. The resulting solution is then left at room temperature overnight. The crystals are filtered, washed with a small volume of ethanol and air dried to yield the ephedrine salt of the title product having an enantiomeric purity of 93% (134.2 g.; 68%).

Provenance & Evidence