Preparation and properties of 1:4(or 1:5)-dimethylglyoxaline and 1:3-dimethylpyrazole / by Hooper Albert Dickinson Jowett and Charles Etty Potter.

  • Jowett, H. A. D. (Hooper Albert Dickinson)
Date:
[between 1900 and 1909?]
Catalogue details

Licence: In copyright

Credit: Preparation and properties of 1:4(or 1:5)-dimethylglyoxaline and 1:3-dimethylpyrazole / by Hooper Albert Dickinson Jowett and Charles Etty Potter. Source: Wellcome Collection.

    3/8 (page 466)
    The base, which distilled at 203° under the ordinary pressure, is a colourless liquid, soluble in water, alcohol, and ether in all proportions, and has a characteristic odour recalling both that of pyridine and of trimethylamine; it has a sp. gr. T003 at 15°/15°. l:4(or 1 :5)-Dimethylglyoxaline was obtained by the following methods: (i) by the action of methyl iodide on the silver derivative of 4(or 5)-methylglyoxaline, in methyl-alcoholic solution, in a sealed tube at 160°; (ii) by the action of sodium methyl sulphate on the sodium derivative of the methylglyoxaline in boiling amyl-alcoholic solution ; but in neither of these two cases was the yield of dimethyl compound so satisfactory as in the method just described. The aurichloride formed yellow needles, which, when crystallised from alcohol, melted at 176°, but after remaining in a desiccator over sulphuric acid for two or three days, the crystals melted at 214—215°. The picrate immediately crystallised in long, yellow needles, which, after crystallisation from hot water, melted sharply at 167°, and were not altered by further crystallisation. The platinichloride slowly separated from solution in orange-coloured, laminar crystals, which, after recrystallisation, melted and decomposed at 239° : 0-0972 gave 0-032 Pt. Pt = 32-9. (C5H8N2)2,H2PtC]6 requires Pt = 32*4 per cent. The hydrochloride was obtained on evaporating the aqueous solution in a vacuum over caustic potash, as a mass of very hygroscopic, colour¬ less crystals melting at 145°. The methiodide was prepared by heating the 4(or 5)-methylgly- oxaline in a sealed tube at 110° for 3 or 4 hours with methyl iodide and methyl alcohol. On evaporation, the methiodide of dimethylgly- oxaline slowly crystallised. It was redissolved in absolute alcohol, boiled with animal charcoal, filtered, and dry ether cautiously added to the solution while still warm, when the methiodide crystallised in fine needles. This operation was repeated until the product was colourless, and the melting point constant at 156°: 0-2538 gave 0-2494 Agl. 1 = 53-1. C5HsN2,OH3I requires 1 = 53*3 per cent. Action of Bromine. (1) In Acetic Acid Solution.—Dibromodimethylglyoxaline was pre¬ pared in a similar manner to dibromoisopilocarpine (Trans., 1901, 79, 580), and formed long, colourless needles, which melted sharply at 127°, and are soluble in alcohol and ether? but insoluble in water ;