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.

    5/16 (page 1968)
    ments point to the conclusion that both the bases in question are internally compensated compounds. The relation between them must, therefore, be of the nature of a cdsdrans-isoinerism, as con¬ cluded by Willstatter (Joe. cit.). Attempts were made to racemise tropine by heating the latter at high temperatures with hydrochloric acid, but these were unsuccessful. xp-Tropine d-camphorsulphonate (m. p. 224—226°) and d-bromo- camphorsulphonate (m. p. 180°) were prepared and fractionally crystallised, but no evidence of resolution could be obtained. The normal and hydrogen d-tartrates were also prepared, but these salts could not be crystallised. The d-camphorsulphonate (m. p. 176—177°) and d-bromocamphorsulphonate (m. p. 190°) of benzoyl- i/'-tropeine were then prepared; these salts crystallised well, and were submitted to a prolonged fractionation, but no separation could be effected in either case. Tropine d-camphorsulphonate (m. p. 236°) and benzoyltropeine d-camphorsulphonate (m. p. 240°) wrere next investigated, and were found, like the preceding salts, to be incapable of resolution. Finally, tropinone was prepared, both from tropine and from i^-tropine, and the base obtained from each source was converted into its d-camphorsulphonate. The two preparations of tropinone d-camphorsulphonate (m. p. 216°) thus obtained were found to be incapable of resolution, and were in all respects identical. Further and conclusive proof that tropine is an internally com¬ pensated compound was obtained by a study of the resolution of atropine. This base is, of course, the tropine ester of dZ-tropic acid, the latter containing one asymmetric carbon atom. Now, if atropine is a derivative of internally compensated tropine, it would, on resolution, yield only two bases, but if it is derived from racemic tropine, it should be capable of resolution into four stereoisomeric bases, or, at all events, in the latter case, it would be possible to obtain proof of the existence of more than two isomerides. Atropine d-camphorsulphonate was therefore prepared, and submitted to fractional crystallisation. It was then found that resolution was readily effected, but the operation yielded only two salts, namely, d- and \-hyoscyamine d-camphorsulphonates. Atropine must therefore contain only one racemic asymmetric carbon a^om, namely, that contained in the tropic acid molecule. Z-Hyoscyamine d-camphorsulphonate melts at 159°, and the specific rotation of the base contained in it, calculated from that of the salt, is [a]D —32T°. This figure is considerably higher than any value previously obtained for the rotation of hyoscyamine, the pure base being usually stated to have about [a]D-21*0°. It was, however, found impossible directly to obtain from the camphor-