The solution was
steam-distilled at 55C for 3 h under reduced pressure
(95 mmHg). The distillate (900 ml) was extracted with
100 ml dichloromethane, using a liquid-liquid continuous
extractor, for 6 h. After the extract was dried
over anhydrous sodium sulfate, the solvent was
removed by a rotary flash evaporator. The distillation
was stopped when the volume of extract was reduced to
approximately 1 ml, and then the solvent was further
removed under a purified nitrogen stream until the
volume was reduced to 0.6 ml.