The constitution of pilocarpine / by Hooper Albert Dickinson Jowett.

  • Jowett, H. A. D. (Hooper Albert Dickinson)
Date:
[1900-1905]
Catalogue details

Licence: In copyright

Credit: The constitution of pilocarpine / by Hooper Albert Dickinson Jowett. Source: Wellcome Collection.

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    steam. The acid liquid was extracted with ether, the ethereal solution dried over calcium chloride, and distilled. The residual liquid, which had a strong, rancid smell, was distilled at atmospheric pressure, when a small fraction was collected below 120°, but the greater portion came over between 120° and 155°, leaving no residue. On adding a little water to the higher fraction, oily drops separated, which dissolved on the addition of more water. From the aqueous liquid, a crystalline barium salt was prepared; this was extracted with boiling alcohol, in which it was very slightly soluble. (i) The portion dissolved by alcohol gave a white, silver salt, which was not reduced on standing. On analysis the following result was obtained : 0-0388 gave 0-0214 Ag. Ag = 55'2. (ii) The residue after extraction with alcohol gave a crystalline silver salt, which was recrystallised from hot water. On analysis, the following result was obtained : 00592 gave 0-0328 Ag. Ag = 55-4. C4H^02Ag requires Ag = 55-38 per cent. The calcium salt was soluble in warm water, but separated again on cooling. The analytical numbers, boiling point, immiscibility with water, and solubility of the calcium salt, prove conclusively that the acid formed is isobutyric acid. The portion boiling below 120° gave a small amount of an amorphous barium salt, insoluble in alcohol, and an amorphous silver salt (Ag = 57‘4 per cent.), which underwent reduction on standing. No trace of acetic acid could be found. Further investigation of the subject is proceeding on different lines, and it is hoped, either by the use of larger quantities of material, or by synthetical methods, to bring forward further proof of the correctness, or otherwise, of the formula now proposed for the acid C7H10O4. The Wellcome Chemical Research Laboratories. RICH A 1<D CLAY AND SONS, I.IMITKD, LONDON AND BUNGAY.