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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    0-1416 gave 0-2103 AgBr. Br = 63'2. C5HgN’2®*’2 requires Br = 63-0 per cent. An attempt to reduce a small quantity of dibromodimethylglyoxaline with sodium and amyl alcohol gave a negative result. (2) In Aqueous Solution under Pressure.—A preliminary experi- ment on a small quantity of dimethylglyoxaline showed that with excess of bromine in aqueous solution at 100° under pressure, no di- bromodimethylglyoxaline was formed, but a crystalline acid was produced, containing both nitrogen and bromine, together with small quantities of ammonia and methylamine. The reaction will be further studied. Oxidation with Potassium Permanganate,—2-5 grams of dimethyl- glyoxaline were oxidised with potassium permanganate at the ordinary temperature, and the products of the reaction isolated in the usual manner. The colour of the permanganate was not discharged imme- diately, but disappeared on allowing the mixture to stand a short time. The reaction may be represented by the equation : OgFgNg + 2O2 -1- 2H2O = NH3 -H NH2-CH3 + CH3-C02H -i- 2CO2. The amount of permanganate required, according to this equation, should be 11 grams, the amount actually used was 11-2 grams. The bases formed were identified as ammonia and methylamine, the yield being theoretical; the platinichloride of the latter was isolated and analysed (Pt = 41'l per cent.). The acid formed was identified as acetic acid by the formation of ethyl acetate. The products of this oxidation are therefore ammonia, methylamine, and acetic acid. Action of Aqueous Caustic Potash on the Methiodide.—Dimethyl- glyoxaline methiodide was heated with 20 per cent, caustic potash in a sealed tube at 180°, and the products of the reaction, which were isolated in the usual manner, were identified as acetic acid and methyl- amine, the latter being isolated in the form of its platinichloride (Pt = 40-9 per cent.). , o ... 7 , 7 HC-N(CHA 1 -.Z-Dimethylpyrazole, )^^’ 1 ; 3-Dimethylpyrazole was prepared from 3-methylpyrazole by the agency of. the methiodide as follows. Ten grams of 3-methylpyrazole were dissolved in methyl alcohol, 34'5 grams of methyl iodide added, and the mixture heated in a sealed tube at 110° for 4 or 5 hours. When cold, a large quantity of crystalline dimethylpyrazole methiodide separated, this product being collected and washed with alcohol and