Preparation and properties of 1:4 (or 1:5)-dimethylglyoxaline and 1:3-dimethylpyrazole / by H.A.D. Jowett and C.E. Potter.

  • Jowett, Hooper Albert Dickinson, 1870-1936.
Date:
[1903]
Catalogue details

Licence: In copyright

Credit: Preparation and properties of 1:4 (or 1:5)-dimethylglyoxaline and 1:3-dimethylpyrazole / by H.A.D. Jowett and C.E. Potter. 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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    Action of Bromine. (1) In Acetic Acid Solution.—Dibromodimethylpyrazole, which was prepared in the same manner as the dibromodimethylglyoxaline, formed long, white needles melting at 74°; these were very soluble in ethyl or methyl alcohol, and in ether or acetone, but insoluble in water: 0-2018 gave 0-3010 AgBr. Br = 63-4. 05HglS’2Br2 requires Br= 63 per cent. (2) In Aqueous Solution under Pressure.—This reaction was found to yield the same product as the previous one. Attempts to reduce the dibromodimethylpyrazole with zinc dust and glacial acetic acid, and also with sodium and boiling amyl alcohol, were unsuccessful. Oxidation with Potassium Permanganate. Dimethylpyrazole on oxidation with permanganate at 80° yielded no volatile base, but an acid forming colourless laminar crystals melt- ing at 222°. The crystals were moderately soluble in hot water, and almost insoluble in cold : 0-1266 gave 0-2208 CO2 and 0-0554 H2O. C = 47-6; H-4-8. C5Hg02N2 requires C = 47'6 ; H = 4-8 per cent. The product of oxidation was therefore iV^-methylpyrazolemono- crbo^ylio acid, Action of Caustic Potash under Pressure on the Methiodide. This experiment was carried out in the usual manner, but as the amount of volatile bases formed was so minute, it was evident that the reaction had not taken place so readily or so completely as was the case with the glyoxaline ; it was therefore not further investigated. 1 :2-Dimethylglyoxaline, CH-N(CH3) CH IS >C-CH 8- This compound was prepared in a precisely similar manner to that given above for the preparation of 1 :4(or 1 :5)-dimethylglyoxaline, that is, by the action of the sodium derivative of 2-methylglyoxaline on sodium methyl sulphate. A fraction boiling at 205—206° was analysed with the following result,: