Orientation of the nitro- and arylazo-glyoxalines. Fission of the glyoxaline nucleus / by Robert George Fargher.

  • Fargher, Robert George.
Date:
1920.]
Catalogue details

Licence: Public Domain Mark

Credit: Orientation of the nitro- and arylazo-glyoxalines. Fission of the glyoxaline nucleus / by Robert George Fargher. Source: Wellcome Collection.

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    LXX.—Orientation of the Nitro- and Arylazo- glyoxalines. Fission of the Glyoxalone Nucleus. By Robert George Fargher. In the course of a recent communication (T., 1919, 115, 217), the author, in conjunction with Prof. F. L. Pyman, showed that the nitro-group, on entering the glyoxaline nucleus, takes up the 4- or 5-position.* Subsequent reduction with tin and hydrochloric acid, undertaken with the object of examining the corresponding amino- glyoxalines and determining directly the orientation of the nitro- group, led to fission of the nucleus, two of the three nitrogen atoms appearing in the form of ammonia. It was suggested that the first stage of the disintegration was probably the elimination of the amino-group as ammonia with formation of a glyoxalone, certain members of the purine group—also derivatives of 4-amino- glyoxaline—having been shown to undergo hydrolysis in this manner (compare Tafel and Meyer, Ber., 1908, 41, 2546; Biltz, Ber., 1910, 43, 1589). It was therefore of interest to investigate the reduction in more detail with the objects (1) of determining directly the orientation of the nitro-group, (2) of establishing the transformation into the glyoxalone, and (3) of studying the fission of the simple glyoxalone nucleus under the influence of acids. The earlier experiments had shown that the products of complete reduc¬ tion, apart from ammonium chloride, the predominant constituent, were very uninviting in appearance. Consequently, treatment in cold hvdrochloric acid solution with just sufficient stannous chloride to reduce the nitro-group was employed, with success. Nitro- glyoxaline, in addition to ammonia, yielded glycine, as did also nitro-2-methylglyoxaline, whilst nitro-5-methylglyoxaline yielded a-alanine. This clearly demonstrates that the nitrogly ox alines are correctly formulated as 4-nitro-derivatives, that the reduction is followed by hydrolysis of the 4-aminoglyoxaline (II), with the N02-C OH-NIF N >CH ■Ns (I.) CH*NH _ > NH2.y_N>CH (II.) CHyNHx I r ^0H CO i— cm.) nh2-ch2-co2h (IV.) * In glyoxalines containing a free imino-group the 4- and 5-positions are equivalent.