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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    rotation being observed at definite intervals by cooling the solu¬ tion and removing the requisite volume for the observation. On completion of the latter, the solutions were recombined and the boiling started afresh. The following data were obtained, using a 2-dcm. tube: Initial reading . —141/ After 4 hours’ boiling . —159' After 1 hour’s boiling ... —149' ,, 6 ,, „ . —1617 ,, 2 hours’ „ ... —153' „ 9 „ „ —157' The solution was now thoroughly extracted with purified ether to remove the Z-tropic acid. The residual aqueous solution still showed a rotation of —10', and contained non-hydrolysed hyoscine, as it gave a reaction with Mayer’s reagent (oscine gives no reaction in acid solution of this strength). The hydrolysis was continued for a further five hours, when the rotation rose to — llr, and the reaction for hyoscine was negative. On removal of the Z-tropic acid by ether, the residual solution was inactive. The ethereal extracts gave 0*65 gram of crude Z-tropic acid melt¬ ing at 125—127° and having [a|D -70*5° in water (c = l). On recrystallisation from water, it melted at 127—128° and gave [a]n —76° (c = 2). . The eZZ-oscine hydrobromide solution was concentrated rapidly under diminished pressure to a syrup, when it acquired a purple colour, which disappeared on dilution with water, but in absolute alcohol became brown. The syrupy residue crystallised on inocu¬ lating with fifZ-oscine hydrobromide. The crude product melted at 270° and weighed 0*75 gram (theory, 0*78). It was triturated with a little absolute alcohol, and the crystals were collected. The product consisted of granular crystals with a violet colour (prob¬ ably containing traces of a perbromide (compare Schmidt, Arch. Pharm.., 1905, 243, 567), weighed 0*53 gram, and melted at 280°. A mixture with pure eZZ-oscine hydrobromide (m. p. 282°) also melted at 280°. The filtrate was now evaporated to dryness under diminished pressure, dissolved in 10 per cent, sodium hydroxide solution, and completely extracted with chloroform. On removal of the chloroform, 0*15 gram of base was obtained, which only crystallised on inoculation with the tZZ-oscine base of commerce. It melted at 98—100°, and a mixture with pure oscine melted at 103°. The products of the hydrolysis are therefore Z-tropic acid and eZZ-oscine. With Hydrochloric Acid.—Pure Z-hyoscine base prepared from 0*5014 gram of Z-hyoscine hydrobromide, [o]D —22*75° (c = 2*5), using sodium hydrogen carbonate and chloroform, was dissolved in