The constituents of the flowers of Trifolium incarnatum / by Harold Rogerson.

  • Rogerson, Harold.
Date:
[1910]
Catalogue details

Licence: Attribution 4.0 International (CC BY 4.0)

Credit: The constituents of the flowers of Trifolium incarnatum / by Harold Rogerson. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    Isolation of Pratol, C10H12O4. The final fraction of the above-mentioned sodium carbonate extracts - of the ethei'eal liquid yielded, when acidified, a pre- cipitate which could not be directly purified by crystallisation. It was therefore acetylated, and the acetyl derivative so obtained crystallised from a mixture of alcohol and ethyl acetate, when it separated in needles, melting at 166°. The amount of this sub- stance was insufficient for analysis, but on comparing it with the acetyl derivative of pratol, C10H12O4 (Power and Salway, loc. cit., p. 233), the two compounds were found to be identical. Isolation of a New Glucoside, Incarnatrin, .C21H20O12,3H2O. The original aqueous liquid (A), which had been repeatedly extracted with ether as above described, was shaken with many successive portions of amyl alcohol. These liquids were united, washed with water, and concentrated under diminished pressure to a volume of about 500 c.c., when, after some time, a yellowish- brown precipitate was deposited, which was collected and washed with light petroleum. By the further concentration of the amyl- alcoholic liquid, a much larger quantity of a yellow precipitate was obtained, which was similarly collected and washed. The final amyl-alcoholic filtrate was concentrated and treated with light petroleum, when a further small quantity of yellow product was obtained. Each of these precipitates was dissolved in a small amount of alcohol, and the solutions kept for some time, when small amounts of a crystalline product were obtained, which were finally united and crystallised from water. A quantity (0‘4 gram) of a substance then separated in faintly yellow, prismatic needles, which softened at 165°, and decomposed at 242—245°. The sub- stance was first dried in a vacuum, and then analysed: 0-1490 lost 0-0136 H20 at 115—120°. H20 = 91. 0-1354* gave 0'2702 C02 and 0‘0600 H20. C = 54’4; H=4 9. C21H20O]2,3H2O requires H2O = 10-4 per cent. C21H2()012 requires C = 54-3; H=4‘3 „ From these results it would appear that this substance possesses the formula C21H20O12,3H2O, but that a little of the water of crystallisation had been lost on drying in a vacuum. The glucosidic character of this substance was established by heating a portion of it for about two hours with 25 per cent, aqueous sulphuric acid. On cooling, a yellow, crystalline substance was deposited, which yielded an acetyl derivative melting at