Chemical examination of jalap / by Frederick B. Power and Harold Rogerson.

  • Frederick Belding Power
Date:
[1910?]
Catalogue details

Licence: In copyright

Credit: Chemical examination of jalap / by Frederick B. Power and Harold Rogerson. Source: Wellcome Collection.

    34/40 (page 110)
    (m. p. 217-218°). The portion of the extract insoluble in water represents the product known as ‘‘resin of jalap,” which is recognized by most of the national Pharmacopoeias. The amount of this resin contained in the drug, as indicated by a special assay of the latter, corresponded,.to 9.4 per cent, of its weight, and 11.6 per cent, of it was soluble in ether. The total crude resin, when purified by means of animal charcoal, had a specific optical rotation of —37-0°. On extracting the crude resin suc¬ cessively with (I) light petroleum (b. p. 40-60°), (II) ether, (III) chloro¬ form, (IV) ethyl acetate, and (V) alcohol, a number of products were obtained, the examination of which has shown the resin to be of much more complex composition than has previously been assumed. I. Petroleum Extract of the Resin.—This represented 1.9 per cent, of the total resin. It contained palmitic and stearic acids in a free state, and, after hydrolysis, yielded formic, butyric and higher volatile acids, palmitic acid, and a mixture of unsaturated acids, which appeared to consist chiefly of linolic acid. From the unsaponifiahle portion of the extract there were obtained a phytosterol, C27H460 (m. p. 134-135°; Md —32.40), cetyl alcohol, C16H340, and a small amount of a substance melting at 56-57°, which agrees in composition with the formula C18H360. This substance, which appears to be a new compound, yields color re¬ actions similar to those of the phytosterols. II. Ether Extract of the Resin.—This represented 9.7 per cent, of the total resin. From it there was isolated a small amount of a new, di- hydric alcohol, which possesses the formula C21H3202(0H)2, and is des¬ ignated ipurganol. Ipurganol crystallizes in colorless needles, melting at 222-225°, and has, in pyridine solution, [a]D —44.90. It yields color reactions similar to those given by the phytosterols. Diacetylipurganol, C2iH3204(CH3.CO)2, forms colorless leaflets, melting at 166-167°, and has, in pyridine solution, [a:]D —36.0°. The ether extract, after treat¬ ment with alkalis and dilute sulphuric acid, yielded, furthermore, a little phytosterol and cetyl alcohol, small amounts of volatile acids, and a quantity of amorphous products. III. Chloroform Extract of the Resin.—This represented 24.1 per cent, of the total resin. From it there was isolated a very small amount of /?-methylaesculetin, C9H5(CH3)04. After treatment with alkalis and dilute sulphuric acid this extract yielded, furthermore, formic, butyric, and d-methylethylacetic acids, together with convolvulinolic acid, C15H30O3, and apparently a higher homologue of the latter. Glucose was also produced by this treatment, thus indicating that a portion of the extract was of a glucosidic nature. IV. Ethyl Acetate Extract of the Resin.—This represented 22 per cent, of the total resin. On treatment with dilute alcoholic sulphuric acid, it yielded formic, butyric, and d-methylethylacetic acids, together with