The constituents of the leaves and stems of Davesia latifolia / by Frederick Belding Power and Arthur Henry Salway.

  • Power, Frederick B. (Frederick Belding), 1853-1927
Date:
1914.]
Catalogue details

Licence: Public Domain Mark

Credit: The constituents of the leaves and stems of Davesia latifolia / by Frederick Belding Power and Arthur Henry Salway. Source: Wellcome Collection.

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    Isolation of a Benzoyl Derivative of a New Disaccharide, Dibenzoylglucoxylose, G11H18O10(CO,C6H5 The original aqueous liquid (44) which had been extracted with ether, as described above, was next repeatedly shaken with amyl alcohol. The combined amyl-alcoholic extracts were washed with a little water, and the solvent removed for the most part at 100° under diminished pressure, when a dark-coloured, syrupy residue was obtained. In order to remove the last traces of amyl alcohol, water was added, and the mixture concentrated to about half its volume under diminished pressure. The residual aqueous liquid then contained about 30 grams of a dark-coloured, viscid product, which in the course of several days became crystalline. The crystalline substance was collected, washed with dilute alcohol to remove some adhering viscid material, and then further purified by recrystallisation, first from alcohol and finally from water. It separated from the latter solvent in thin, colourless needles, which melted at 147—148°, contained water of crystallisation, and possessed an extremely bitter taste. The amount of this substance isolated from 2 kilograms of the alcoholic extract of the drug was about 20 grams, but on subsequently working up the remainder of the extract the total yield was 220 grams, thus representing about 0*56 per cent, of the weight of drug employed. A larger amount of the crystalline, bitter substance than here indicated was, however, actually present in the drug, inasmuch as some remained in the mother liquors from its crystallisation, and a considerable amount was also contained in the resin. The substance was analysed, with the following results: 1T792, heated at 105°, lost 0'0393 H20. II20 = 3*3. 0T073* gave 0*2254 C02 and 0*0525 H90. C = 57*3; 11 = 5*4. 0*1105 * „ 0*2338 C()2 „ 0*0548 H20. C = 57*7; H = 5*5. C25Il28012,H20 requires H20 = 3*3 per cent. • C25H28012 requires C = 57*7; 11 = 5*4 per cent. The molecular weight of the compound was determined by Barger’s microscopic method. 0*4404,* in 10 c.c. alcohol, was between 0*09 and 0*10 mol., using benzil as the standard. Mean, M.W.=465. C25H28012 requires M.W. = 520. From the above results it is evident that the crystalline, bitter substance possesses the empirical formula C25H28012,H20. Its further examination has revealed the fact that it is a dibenzoyl derivative of a new disaccharide, CnH20O10, the latter yielding on