The configuration of tropine and [psi]-tropine and the resolution of atropine / by Marmaduke Barrowcliff and Frank Tutin.

  • Barrowcliff, Marmaduke.
Date:
[1909?]
Catalogue details

Licence: In copyright

Credit: The configuration of tropine and [psi]-tropine and the resolution of atropine / by Marmaduke Barrowcliff and Frank Tutin. Source: Wellcome Collection.

    6/16 (page 1969)
    sulphonate a base of higher rotatory power than about [a]D — 20‘0°. That this decrease in optical activity was due to the fact that racemisation had occurred was proved by reconverting the base into the camphorsulphonate, when a rather impure product was obtained, from which, by fractional crystallisation, it was possible to separate the salt of a dextrorotatory base. A preparation of Z-hyoscyamine having [a]D —25'8° was, however, obtained by frac¬ tionally crystallising, from an anhydrous solvent, a quantity of the base having [a]D — 20'0°. The ease with which hyoscyamine under¬ goes racemisation in presence of water is shown by the fact that the rotation diminishes on allowing the base to remain dissolved in moist chloroform. These observations render it evident that no optically pure hyoscyamine has yet been obtained, and that, in all probability, the only salts of this base which have been prepared in a state of purity are those described in the present com¬ munication. ^-Hyoscyamine (^-camphorsulphonate was obtained pure only with considerable difficulty. It melts at 135°, and yields a base possess¬ ing properties similar to those of its optical antipode. (7-Hyos- cyamine has not been observed to occur in nature, but it has been obtained synthetical^, although only in an impure state. Laden- burg and Hundt (Ber., 1889, 22, 2590) prepared a base by com¬ bining <7-tropic acid with tropine. This product they called “ d-atropine,” but more recent work has rendered it evident that, in reality, it was impure ^-hyoscyamine. Amenomiya {Arch. Pharm., 1902, 240, 498), employing a method similar to that used by Ladenburg and Hundt, prepared a c?-hyoscyamine of greater purity. This preparation had [a]D+23'0° when in the form of its hydrochloride, the latter having been obtained from the auri- chloride without liberation of the base. Amenomiya, however, did not determine the rotation of the free base obtained from the salt which he had thus prepared. Particular interest is attached to the resolution of atropine, inasmuch as it is known that the two stereoisomeric hyoscyamines differ greatly in their respective physiological activities. Thus, Cushny (J. Physiol., 1904, 30, 176) has shown that Z-hyoscyamine ([a]D —21*0°) has about fourteen times the activity of the d-hyos- cyamine prepared by Amenomiya. The material employed by Cushny was, however, not only partially racemised, but was also, in the case of the (7-base, extremely limited in amount. A more complete comparison of the physiological actions of the two isomerides has therefore been made by Dr. P. P. Laidlaw, at the Wellcome Physiological Research Laboratories, with the employment of the optically pure e?-camphorsulphonates obtained