The resolution of hyoscine and its components, tropic acid and oscine / by Harold King.
- King, Harold
- Date:
- 1919]
Licence: Public Domain Mark
Credit: The resolution of hyoscine and its components, tropic acid and oscine / by Harold King. Source: Wellcome Collection.
21/34 (page 496)
![/-oscine picrat© crystallises very similarly to ^//-oscine picrate. It was therefore necessary to prove that this stable form of /-oscine picrate did actually contain the active base. Accordingly, 0*5 gram of /-oscine picrate (rhombs) was converted as quantitatively as possible by means of ether and three molecular proportions of X 10-hydrochloric acid into /-oscine hydrochloride. The solution was concentrated somewhat and made up to 20 c.c. In a 2-dcm. tube the observed rotation was aD -25-3;, from which it is calcu¬ lated that the /-oscinium ion has [a]D —21°, a value in good agree¬ ment with that observed directly for /-oscinium hydrochloride. The solution was then dried, and the hydrochloride recrystallised from alcohol. It gave 0*11 gram of highly deliquescent /-oscine hydrochloride melting at 271—272°, and when tested with satu¬ rated picric acid solution gave the unstable needle form of /-oscine picrate, changing into rhombs. 1 -Oscine Base.—To avoid the action of alkalis, which it was thought might cause partial racemisation, /-oscine base was pre¬ pared as follows. /-Oscine picrate (4'75 grams) was treated with three equivalents of dilute sulphuric acid solution, and the picric acid removed by purified ether. After treating with charcoal to remove the last traces of picric acid, the solution was concentrated under diminished pressure to about 20 c.c., and excess of pure barium carbonate added. On allowing to remain overnight, the solution was free from sulphanion, and only contained /-oscine partly present as carbonate. The major portion of the /-oscine was readily removed by extraction with freshly purified chloroform, the remainder being retained by the dissolved carbon dioxide. When the latter solution was evaporated to dryness in a vacuum over sulphuric acid and redissolved in a little water, the rest of the oscine was readily extracted by chloroform. In this way, the /-oscine was recovered quantitatively as base. The first chloroform extract on complete removal of the solvent crystallised at once. The product was white and amounted to 1*45 grams. It had a specific rotatorv power of [a]D — 52'8° in water. It melted at 109—110°, the same as ^/-oscine, whilst a mixture of the two showed no depression of the melting point. When recrystallised from light petroleum, it separated in long needles, the melting point was unchanged at 109‘5—110'5° (corr.). The specific rotatory power was determined in water : c = l‘010; Z = 2-dcm.; a— PS'G'; [ajD —52*4°. With Mayer’s reagent (potassium mercuric iodide), /-oscine base gives no precipitate, but in the form of a salt it gives a crystal-](https://iiif.wellcomecollection.org/image/b30622074_0021.jp2/full/800%2C/0/default.jpg)
