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.

    20/34 (page 495)
    * ' 9 v i 1 , « • J » » t * V $ f 1 t anhydrous, and either form when mixed with (7Z-oscine picrate, which itself also melts at 237—238°, shows no depression of the melting point. At the ordinary temperature, the needle form of picrate is certainly the unstable one, as is readily shown by adding a drop of saturated picric acid solution to a few small crystals of Z-oscine ^/-hydrogen tartrate and rubbing- with a glass rod. The crystals dissolve instantly, and a homogeneous crop qf needles first npakes its appearance, followed quickly by minute rhombs, and in a short time the needles will have entirely disappeared, their dis¬ integration and solution being readily followed with the aid of a microscope. This behaviour is useful as a test as to whether one is dealing with active or dl-oscine salts, since (7Z-oscine picrate has always .been observed to separate in small, flattened rhombs. 1 -Oscine Hydrochloride.—Four grams of Z-oscine picrate (needle form) were decomposed by shaking with three molecular propor¬ tions of 5 per cent, hydrochloric acid, and the picric acid was removed by ether. The solution of the Z-oscine hydrochloride was completely dehydrated by repeated evaporation to dryness with absolute ^al^ohol, leaving, finally, a white, crystalline powder, which was dissolved in 10 c.c. of boiling absolute alcohol. On keeping, Z-oscine hydrochloride separated in aggregates of small prisms in fhe foqm of warts; a few isolated prisms were also present. The product was collected, and amounted to 1*4 grams. It melted and decomposed at 273—;^74° (281—282° corr.). A mixture with cZZ-oscine hydrochloride (m. p. 273—274°) also melted at the same temperature. Unlike cZZ-oscine hydrochlqride, the laeyo-salt is very highly deliquescent. A direct comparison of the two was made by eypq^ing a few crystals of each on watch-glasses to the atmosphere. In a few minutes, the laevo-salt had completely liquefied, whilst the <7Z-salt was apparently unaffected. On keeping for an hour, how¬ ever, the lafter showed signs of deliquescence, and the deliquesced salt recrystallised in well-formed tablets melting partly at about 100°, and probably representing the monohydrated qZZ-oscine hydro¬ chloride described by Luboldt {Arch. Phann., 1898, 236, 18). The specific rotation of Z-oscine hydrochloride was determined in water, employing a salt which had been dried at 100°: c —0-997 ; l — 2-dcm.; a=-23*6/; [a]D -19-71°; [M]D -37-76°; whence [a]D for the Z-oscinium ion is —24-2°, whereas the value calculated from the molecular rotation of Z-oscine (7-hydrogen tartrate was —24-7°. 1 -Oscine Hydrochloride from 1 -Oscine Picrate (Rhombs).—As _ t has been indicated above, eZ'Z-oscine picrate and Z-oscine picrate melt at the same temperature, and the stable modification of