The constituents of Withania somnifera / by Frederick B. Power and Arthur H. Salway.

  • Power, Frederick B. (Frederick Belding), 1853-1927.
Date:
1911
Catalogue details

Licence: In copyright

Credit: The constituents of Withania somnifera / by Frederick B. Power and Arthur H. Salway. 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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    this solvent in thin, hair-like needles, which sintered at 240°, and melted and decomposed at about 250°. The yield of this substance was 4 grams: 0'4704, dried at 110°, lost 0'0310 H,0. H20 = 6 6. 0T160* gave 0‘3037 CO, and 0-0898 H20. C = 71‘4; H = 8-6. 0-1071* „ 0-2805 C02 „ 0’0830 H20. C=71‘4- H = 8'6. C33H4U07,2H26 requires H,0 = 6T per cent. C33H40O7 requires C=71*5; H = 83 per cent. A molecular-weight determination by the cryoscopic method gave the following result: 0-2454,* in 33'80 nitrobenzene, gave \t= — 0'092°. M.W. = 553. requires M.W. = 554. No compound of the above formula appears to have previously been described. It is therefore proposed to designate the sub- stance somnitol, with reference to its alcoholic character and the specific name of the plant from which it has been obtained. Somnitol is practically insoluble in water, and only moderately soluble in hot absolute alcohol. It dissolves readily in chloroform and in dilute alcohol, separating from the latter solvent with 2 molecules of water. The compound is optically active, a deter- mination of its rotatory power giving the following result: 0'3040,* made up to 25 c.c. with chloroform, gave oD +0°31/ in a 2-dcm. tube, whence [a]D -t-212°. When somnitol is heated with alkali hydroxides in alcoholic solu- tion it slowly undergoes change, and the liquid acquires a deep red colour, but even after prolonged heating with concentrated alkali a part of the compound was recovered unaltered. The reaction is therefore not comparable with that which takes place when somnirol is similarly treated, since in the latter case no trace of unchanged substance can be detected, even after a few minutes’ heating with the alkali. Somnitol contains no methoxyl, but was found to possess two hydroxyl groups, since it readily yields a diacetyl derivative. Diacetylsomnitol, C33H4407(C0'CH3)2.—This compound was pre- pared by heating somnitol with acetic anhydride for an hour. On concentrating the solution, an acetyl derivative separated in colour- less prisms, which, after recrystallisation from acetic anhydride, melted and decomposed at 270—275°. It was practically insoluble in cold acetic anhydride or alcohol, but readily soluble in chloroform: 0-1127 gave0-2866 CO, and 0‘0841 H,0. C-69‘4; H = 83. 0-1056 „ 0-2693 C02 „ 0‘0782 H,0. C = 69 6; H = 8'2. C33H4107(C0-CH3)2 requires C = 69 6; H = 78 per cent.