Potassium carbonate Scopolamin hydrobromide

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 separation of atropine, Z-hyoscyamine and Z-scopolamine has been effected by the fractional crystallization of their aurichlorides. It has been pointed out, however, that the solubility relations of these derivatives are dependent upon impurities and the relative amoimts of each present in the mixture (50). The bases may be recovered by decomposing an aqueous solution of the aurichloride with hydrogen sulfide and filtering to remove the gold sulfide. The base is liberated by addition of potassium carbonate to the filtrate and extraction with chloroform. An alternate method for the separation of atropine and Z-hyoscyamine (25) is by fractional crystallization of their oxalates from acetone and ether in which the Z-hyoscyamine derivative has the greater solubility. Z-Scopolamine and dioscorine on the other hand are purified through their insoluble hydrobromides. 

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