Dibenzoylglucoxlose : a natural benzoyl derivate of a new disaccharide / by Frederick Belding Power and Arthur Henry Salway.

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

Licence: Public Domain Mark

Credit: Dibenzoylglucoxlose : a natural benzoyl derivate of a new disaccharide / by Frederick Belding Power and Arthur Henry Salway. Source: Wellcome Collection.

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    The optical rotation of glucoxylose could not be determined directly on account of its hygroscopic nature and the deepening of colour produced on drying it at an elevated temperature. The determination of its rotation was therefore accomplished indirectly in the following manner: 1T050 Grams* of dibenzoylglucoxylose ( = 0*6630 gram of gluco¬ xylose) were hydrolysed by cold aqueous barium hydroxide, and the barium was then exactly precipitated by its equivalent of sulphuric acid. The precipitate of barium sulphate was subsequently removed by filtration, washed well with water, and the filtrate and washings made up to the volume of 100 c.c. This solution, con¬ taining the glycoxylose, together with some benzoic acid, gave aD —0°29/ in a 2-dcm. tube, whence [aJD —36*5°. A second deter¬ mination, performed in a similar manner, gave [a]D —35‘8°. It may be considered that the accuracy of these results would not be appreciably influenced by the small amount of benzoic acid present in the solution. A quantity of glucoxylose was heated for some time with acetic anhydride for the purpose of preparing an acetyl derivative, but the product could not be obtained in a crystalline state, and there¬ fore was not further investigated. Acid Hydrolysis of Glucoxylose. Formation of Dextrose and Xylose. To an aqueous solution of glucoxylose, prepared from 20 grams of the dibenzoyl derivative, such an amount of sulphuric acid was added as to have the latter represent 5 per cent, of the total liquid, and the mixture then heated at 100° for about an hour. The sulphuric acid was afterwards removed by the addition of an exact equivalent of barium hydroxide, and the mixture filtered. The filtrate, which was now dextrorotatory, was concentrated under diminished pressure until the water was removed as completely as possible. The residual syrup was then dissolved in hot absolute alcohol, and ethyl acetate cautiously added to the solution, when, on cooling, a syrupy deposit was produced, from which the mother liquor was decanted. The latter was kept for several days, when hard, wart-like aggregates of anhydrous crystals, melting at 146°, were gradually formed. This crystalline substance was collected and analysed. (Found, C = 40*0; H = 6'7. CfiH19Ofi requires 0 = 40 0; H = 6’7 per cent.) An aqueous solution of the substance exhibited the phenomenon