Scopolamine hydrobromide trihydrate

In a one-liter separatory funnel, 94 g (0.215 mol) of scopolamine hydrobromide trihydrate was dissolved in 250 ml of water, made alkaline by shaking with 40 g (1 mol) of sodium hydroxide in 150 ml of water, and the free base immediately extracted with ether. As scopolamine is somewhat soluble in water, the aqueous layer was saturated with potassium carbonate and again extracted with ether. The combined ether extracts were dried over anhydrous magnesium sulfate and the ether removed by distillation, leaving 65 g (0.214 mol 100% yield) of nearly colorless oil. Then 100 g (1.05 mols) of cold methyl bromide was added to a chilled, 500-ml pressure flask containing the 65 g of scopolamine, the flask stoppered tightly with a clamp, and allowed to stand at room temperature for 96 hours. 

The salt was recrystallized from 550 ml of alcohol first crop, 70 g, MP 212° to 214°C second crop, 6 g, MP 195° to 200°C. The combined crops were again recrystallized from 500 ml of 3-A alcohol MP 210° to 212°C. The third recrystallization from 600 ml of alcohol yielded 64 g, MP 214° to 216°C, a 75% yield based on scopolamine hydrobromide trihydrate starting material. 

Scopolamine hydrobromide trihydrate Methyl bromide Silver nitrate... 

CAS Registry No. 51-34-3 (scopolamine), 6533-68-2 (scopolamine hydrobromide trihydrate), 114-49-8 (scopolamine hydrobromide anhydrous)... 

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