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.

    25/34 (page 500)
    i obtained by calculation from the rotation of e?-oscine ^-hydrogen tartrate, namely, [a]D 27*1°, and that directly observed, [a]D 24-0°, for <Aoscinium hydrochloride prepared from the tartrate. The free benzoic acid was removed by extraction with purified ether, and the aqueous liquor concentrated to a syrup under diminished pressure on the water-bath. On dehydration of the syrup by evaporation with absolute alcohol, the residue crystal¬ lised. It was dissolved in a little hot absolute alcohol, and, on keeping, O'07 gram of crystals resembling ammonium chloride were collected. They melted and decomposed in the neighbourhood of 243° (pure c?-oscine hydrochloride melts at 273°), and were highly deliquescent. Twenty milligrams of this salt, wrhen treated with an equal weight of picric acid in hot aqueous solution, gave a picrate crystal¬ lising in long, fine needles, and later a few rhombs separated, a behaviour which is exactly reproduced by the addition of picric acid solution to the pure d- or f-oscine ^-hydrogen tartrates (p. 495). This picrate, when collected and dried, melted and decomposed at 237—238°. A mixture with d-oscine picrate melted in the same bath at 237—238°. The alcoholic mother liquors of the above O’07 gram of e£-oscine hydrochloride were combined with picric acid (both in aqueous solution). The addition of the picric acid first precipitated amorphous matter, which was separated, and later a well-crystallised picrate. This salt crystallised in small rhombs, melted and decomposed at 235°, and was in all probability the stable form of <i-oscine picrate. With Alkali.—Pure benzoyl-<Aoscine hydrochloride (0-4009 gram) was dissolved in water, and 5 c.c. of 10 per cent, sodium hydroxide were added. The oily base, which separated rapidly, disappeared on boiling. After an hour, the solution was cooled and neutralised to Congo paper with hydrochloric acid. The pre¬ cipitated benzoic acid was completely removed by ether extraction, and the extracted aqueous liquor was also free from non-hydrolysed benzoyloscine, as was indicated by the absence of a turbidity on treatment with Mayer’s reagent in acid solution. In neutral or very faintly acid solution it gave the well-crystallised precipitate observed with oscine salts. The solution was rapidly concentrated and made up to 20 c.c. In a 2-dcm. tube it gave aD+32'8', whence the c?-oscinium ion has [a]D +25*8°, a value in good agree¬ ment with that observed by acid hydrolysis, [o]D +26*0°, and that observed for pure ^/-oscine hydrochloride, [a]D + 24*0°.