A laevo-rotatory modification of quercitol / by Frederick B. Power and Frank Tutin.

  • Power, Frederick B. (Frederick Belding), 1853-1927.
Date:
[1904]
Catalogue details

Licence: Attribution 4.0 International (CC BY 4.0)

Credit: A laevo-rotatory modification of quercitol / by Frederick B. Power and Frank Tutin. 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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    An attempt was made to determine the molecular weight of Z-quercitol in phenol solution, but it was not sufficiently soluble. The acetyl derivative was therefore selected for this purpose, and its mole- cular weight was determined by the cryoscopic method in benzene solution. 0-4288 in 24-38 benzene gave - 0-248°. M. W. = 348. CjqH220jo requires M. W. = 374. The number of acetyl groups in this compound was determined by hydrolysing a weighed quantity of the substance with a known volume of standard alcoholic solution of sodium hydroxide and titrating the excess of alkali with standard acid. The percentage of acetyl found by this means was 80-3, the theoretical percentage for five acetyl groups being 78-9. It was observed that the penta-acetyl-7-quercitol which had been crystallised from benzene melted at 87—97°, but after heating to 80° for a short time melted at 124—125°, which is the melting point of the anhydrous substance. The whole of the benzene was also given off in the course of two or three days at the ordinary tempera- ture. A portion of the acetyl derivative was crystallised from benzene, pressed on a porous tile until free from adhering solvent, and the amount of benzene of crystallisation determined by heating at 100° until the weight of the residue remained constant. 0-5200 lost 0-0880 OgHg. CgHg= 16-9. 0-7142 „ 0-1239 CgHg. CgHg = 17-3. CigH220io)CgHg requires CgHg= 17-3 per cent. PentahenzoylA-quercitol, CgHy(0*C^H50)5. The 7-quercitol was benzoylated by the Schotten-Baumann method, and also by heating it with an excess of benzoyl chloride until hydrogen chloride ceased to be evolved ; the products obtained were identical. Pentabenzoyl-7-quercitol shows the same behaviour towards solvents as the acetyl derivative ■, it separates from alcohol in an amorphous state, melts at 133°, and is anhydrous. A determination of its specific rotatory power in chloroform solution gave the following result: a-2°14'; Z=1 dcm.; c = 2-826 ; [a]o -79'0°. On adding a quantity of light petroleum to a solution of the substance in a mixture of warm ethyl acetate and alcohol, needle-shaped crystals containing one molecule of alcohol slowly separated. These crystals, when dried in the air, melt at 116°, but the melting point is raised to