The action of thionyl chloride on the methylene ethers of catechol derivatives. Pt. II. Piperonyloin, piperil and hydropiperoin / by George Barger and Arthur James Ewins.

  • Barger, George, 1878-1939.
Date:
[1908]
Catalogue details

Licence: Attribution 4.0 International (CC BY 4.0)

Credit: The action of thionyl chloride on the methylene ethers of catechol derivatives. Pt. II. Piperonyloin, piperil and hydropiperoin / by George Barger and Arthur James Ewins. 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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    The substance is extremely stable (except towards alkalis, which attack the carbonyl groups). Boiling for several hours with formic acid scarcely alters it; in this respect, it differs markedly from the similar dichloro-derivative obtained from piperonyloin. According to formula I, the substance would be a derivative of aa/?/J-tetrachloro- s-diphenylethane, which is only attacked by glacial acetic acid at 200°; this suggested the following experiment. One gram of the substance, CieH606Cl4, was suspended in 10 c.c. of glacial acetic acid and heated to 200° for two hours. On cooling, 0'37 gram of the unchanged material was collected. The almost black filtrate gave an intense catechol reaction with ferric chloride; the acetic acid was therefore distilled off under diminished pressure, and the residue was boiled with water and animal charcoal. The almost colourless filtrate deposited in a vacuum over sulphuric acid a minute quantity of long needles, which decomposed at 290—300° without melting. They were insoluble in cold water, but dissolved readily in alcohol; the alcoholic solution gave a green coloration with ferric chloride, changing to reddish-brown by a trace of alkali. The fact that the whole of the chlorine was not removed, and that no tetrahydroxybenzil was obtainable, would indicate that some of the chlorine was in the benzene nuclei, and would therefore support formula II. The amount of substance available did not, however, allow us to investigate this point further. The Wellcome Physiological Reseahch Laboratories, Herne Hill, London, S.E. It. CLAY AND HONS, LTD., BREAD ST. HILL, E.C., AND BUNOAY, SUFFOLK.