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.

    9/34 page 484
    The various possibilities are shown in the following table, the centre column representing optically pure forms, which, combined, as shown by the arrows, yield partially racemic forms: Partial racemates. 5. <ZZ-tropyl-<Z- oscme X Optically pure forms. 1. Z-tropyl-d-oscine 2. Z-tropyl-Z-oscine Partial racemates. 7. Z-tropyl-cZZ- oscine 6. c/Z-tropyl-Z- oscine ^ 3. d-tropy 1-d-oscine 4. cZ-tropyl-Z-oscine ^8. d-tropyl-dZ- oscine Of these, 1 to 6 are at once excluded, since Z-hyoscine on hydro¬ lysis with acid or alkali gives /-tropic acid and ('//-oscine, whereas benzoyl (/-oscine under similar conditions yields optically pure ('/-oscine. On these grounds, Z- and (/-hyoscine, represented by 7 and 8, are therefore partially racemic esters, /-hyoscine being a mole¬ cular combination of Z-tropyl-(/-oscine and /-tropyl-/-oscine, whilst (/-hyoscine is a similar combination of (Z-tropyl-(/-oscine and <7-tropyl-Z-oscine. The known inactivation of Z-hyoscine by alkalis would, on this basis, simply consist in the change of configuration of the tropyl portion of the molecule, probably through the intermediary of the CFL’OH CH„-OH i i OH Ph-OC02R Ph'0:C<Q^ H CH„*OH i 2 Ph-C-H co2r enolic form, and each constituent ester of the partial racemate should give rise to a new ester. In support of this, some work, which is reserved for future publication, on the re-resolution of racemised (Z-hyoscine has resulted in the isolation of two esters only, d- and Z-hyoscine, which is not surprising, as these, being partial racemates, would contain the four expected optically pure forms. As opposed to the partial racemic ester nature of d- and Z-hyoscines may be cited the rarity of the occurrence of partial racemates in nature, and the novel behaviour of the hyoscines towards (7-bromocamphorsulphonic acid, which, so far as (/-hyoscine is concerned, only resolves dl or weakly active hyoscine as far as the partially racemic ester stage. Although this behaviour is, as far as it has been possible to ascertain, unique, it is only necessary to
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