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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    very explicit, merely stating that the specific rotatory power was + 71*4° in solutions of various concentration. As previous workers appeared to have experienced some difficulty in obtaining pure quinine Z-tropate from the mother liquors, a variant was made by converting the recovered partly resolved Z-tropic acid into the quinidine salt. Further, by use of the two stereoisomeric alkaloids quinine and quinidine, but commencing the resolution with quinidine, 55 per cent, of pure quinidine Z-tropate was first isolated, then an 80 per cent, yield of pure quinine eZ-tropate, and simultaneously a 14 per cent, yield of pure quinine Z-tropate. On reverting to quinidine, a further 19 per cent, yield of quinidine Z-tropate was obtained. In this way, approximately 84 per cent, of the tropic acid was resolved into its constituents. It would, however, be probably an advantage, other factors being equal, to start the resolution with quinine and follow with quinidine, since experiment showed that, starting with quinine, 66 per cent, of quinine d-tropate was obtained pure, and, as stated above, starting with quinidine only, 55 per cent, of quinidine Z-tropate could be separated. It is interesting to note that previous attempts to use quinine and quinidine for the resolution of externally compensated acids, in the above sense, have not always been successful. Whereas Fischer, Scheibler, and Groh (Ber., 1910, 4.3, 2022) found that in the resolution of formyl-j8-alanine, quinine separated the laevo- component and quinidine the dextro-, Scheibler and Wheeler (Ber., 1911, 44, 2686) found that in the resolution of eZZ-leucine the same two alkaloids always gave the laevo-acid first. This was also the experience of McKenzie (T., 1899, 75, 969) in the resolution of mandelic acid. Oscine. Tht Basic Hydrolytic Product of Hyoscine. There are numerous instances recorded in the literature of the hydrolysis of Z-hyoscine by alkalis, but the basic hydrolytic pro¬ duct, oscine, C8H1302N, was invariably found to be devoid of optical activity, even in the presence of borates or strong acids (Gadamer, Arch. Pharm., 1901, 289, 322). The only occasion on which Z-hyoscine has been hydrolysed by acids is recorded by Hesse (Annalen, 1892, 271, 100), who carried out the hydrolysis with concentrated hydrochloric acid in a sealed tube at 80—100°. This furnished the base, oscine, but there is no record of its polari- metric examination. To decide this matter, pure Z-hyoscine has now been hydrolysed by boiling with excess of 10 per cent, hydrobromic acid, the change