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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    temperature, it forms a crystalline dibromo-derivative, but with excess of the reagent at 100° under pressure, further action occurs, a crys- talline acid containing both nitrogen and bromine being formed. Chromic acid does not attack the base, but potassium permanganate oxidises it, producing ammonia, methylamine, and acetic acid. When the methiodide is heated with aqueous caustic potash in a sealed tube at 180°, methylamine and acetic acid are formed. 1 : ^-Dimethylpyrazole was prepared through its methiodide from 3-methylpyrazole, which was obtained by the condensation of formyl- acetone with hydrazine (Knorr and Macdonald, Annalen, 1894, 279, 225). Knorr also obtained this base {loc. cit., 231), but had doubts as to its purity, and did not further investigate it. The base is a colour- less liquid forming crystalline salts. With bromine, either at the ordinary temperature or at 100° under pressure, the dibromo-derivative is formed; in the latter respect, the base differs from the isomeric glyoxaline, which is decomposed by excess of bromine at 100°. With potassium permanganate, the corresponding pyrazolemonocarboxylic acid is formed, and the methiodide is not readily decomposed by aqueous caustic potash; in both these reactions the pyrazole behaves differently from the glyoxaline. Professor C. R. Marshall has examined these compounds physiologic- ally, but neither of them was found to possess any action analogous to that of pilocarpine. It was also found necessary to characterise the isomeric 1 : 2-dimethylglyoxaline which had been previously prepared {Ber., 1883, 16, 448), inasmuch as the physical constants of its salts had not been recorded. Experimental. CH,-C- 1 :4(or N: H-C-N(CH3) 1 :5)-Dimethylglyoxaline, >CH or H-C This base was prepared from 4(or 5)-methylglyoxaline by the method (B) given by Titherley for the preparation of monoalkyl-substituted amides (Trans., 1901, 79, 401); it was, however, extracted with ether instead of with benzene. The dark-coloured and oily residue, which was distilled under 20—25 mm. pressure, boiled almost entirely be- tween 110° and 117°, the yield being 60 to 70 per cent, of the theoretical. The product was rectified, and a fraction boiling at 116° under 25 mm. pressure analysed with the following result: 0-1058 gave 0-2426 CO2 and 0-0824 HgO. 0 = 62-5; H = 8 6, 0-1250 „ 0-2850 002 „ 0-0962 H2O. 0 = 62-2; H = 8-5. 0-0808 ,, 20 c.c. nitrogen at 14° and 747 mm. N = 28-9. 05HgN2 requires 0 = 62-5 ; H = 8-3 ; N = 29-2 per cent.
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