The resolution of hyoscine and its components, tropic acid and oscine / by Harold King.

  • King, Harold
Date:
1919]
Catalogue details

Licence: Public Domain Mark

Credit: The resolution of hyoscine and its components, tropic acid and oscine / by Harold King. Source: Wellcome Collection.

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    it can be separated by fractional crystallisation of the hydro- bromides. Racemic hyoscine base, which can also be obtained from Z-hyoscine by the action of alkalis, forms two hydrates, one crystallising with two molecules of water, and known as atroscine (Hesse), the other with one molecule of water. Two attempts to resolve racemic hyoscine are recorded, the first by Schmidt (Arch. Pharm., 1898, 236, 56), who found that the salt with thiocyanic acid did not separate into two mechanically separable crystalline enantiomorphs, as was the case with racemic lupanine (Schmidt and Davis, Arch. Pharm., 1897, 235, 196), the second by Gadamer (Arch. Pharm., 1901, 239, 294), who states that the quinic acid and <7-mandelic acid salts of <7Z-hyoscine are very readily soluble and possess little crystallising power, and are therefore not suit¬ able for the resolution of hyoscine. The primary mode of attack adopted in the present investiga¬ tion is based on some unpublished preliminary experiments by Tutin, who showed that Z-hyoscine of commerce forms a soluble, deliquescent salt with utbromocamphorsulphonic acid which can be recrystallised from dry ethyl acetate containing alcohol, and also that when Z-hyoscine is racemised by alkali, ihe product as a salt with the same acid can likewise be recrystallised, and the successive fractions of salt so obtained show a progressive variation in rotatory power. The author here gratefully acknowledges his indebtedness to Mr. Tutin for placing these results at his disposal. A quantity of crystalline hydrobromides of feeble lsevorotatory power, obtained as a by-product in the manufacture of the thera¬ peutically valuable Z-hyoscine, was fractionally crystallised as a salt with cZ-a-bromo-7r-camphorsulphonic acid, when the first salt to be isolated was meteloidine bromocamyhorsulphonate (m. p. 224—227°). This salt crystallises exceedingly well, and contains «-meteloidine (compare Pyman and Reynolds, T., 1908, 93, 2077). On continuing the fractionation, d-hyoscine bromo- camphorsulphonate was obtained in a state of purity. It melted at 159—160°, and crystallised in glistening, acicular needles. d-Hyoscine hydrobromide was prepared from it, and found to crystallise with three molecules of water and to possess a specific rotatory power [a]D + 23-1°, which corresponds with a value [a]D+33‘4° for the <7-hyoscinium ion. For comparison, some of the maximum values recorded by previous observers for the laevo- salt are tabulated below.