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Triazines
1911 Encyclopedia Britannica
or in organic chemistry, a series of cyclic compounds, containing a ring system composed of three carbon and three nitrogen atoms. Three series are possible, the positions of Marine Trias Of The Alpine And Indian Types.
C02-}-NH3 the various units of the ring system being illustrated in the annexed formulae: C C C NI^C CI C N/C A N ` N' N C,C N N N a-Triazines, (-Triazines, Cyanidines.
Few simple derivatives of the a-series are known, those which have been prepared result by such reactions as the condensation of aminoguanidine or a similar type of compound (e.g. semicarbazide) with ortho-diketones (J. Thiele, Ann., 1898, 302, p. 299): HN:CC NHNH2 OCC 6 H 5 NH N + -> HN:CC CC6 H 5 NH 2 OCC6H5 N = C/-C6H5 Wolff has obtained a chloro-derivative by the action of potassium cyanide on diazoacetophenone and subsequent treatment with acid. The phen-a-triazines are more numerous, and are obtained either by the action of concentrated acids on the formazyl compounds (E. Bamberger, Ber., 1893, 26, p. 2786): CsH5N :N N :N jCCOC6H5 - C6H5NH2+C6H4K C 6 H5NHN N:C0006H5; by the reduction of symmetrical acyl-ortho-nitrophenyl hydrazines (e.g. NO 2 C 6 H 4 NHNHCHO); or in the form of dihydro derivatives by the condensation of aldehydes with ortho-aminoazo compounds (H. Goldschmidt and Y. Rosell, Ber., 1890, 23, p. 487), or from the aminoazo compound and a mustard oil, the resulting thiocarbanilido derivative being heated with acetic acid (M. Busch, Ber., 1899, 32, p. 2960): NC(SH):NC 6 H 5 /NC:NC6H5 C. 2 S 7Hs " H s d-H NNH C,H 7 C7 "NNC,H7 C. Harries (Ber., 1895, 28, p. 1223) has also shown that as-phenylhydrazino-acetic esters, when heated with formamide and substituted formamides under pressure, yield dihydrotriazines: CO 2 R CO-NR'-CH H2N(C6H5)NH2 +R'NHCHO --> CH 2 N(C 6 H 5) IV The phen-a-triazines are yellow-coloured crystalline compounds of a somewhat basic character.
Derivatives of triazines are formed by the action of nitrous acid on ortho-aminobenzylamines (M. Busch, Ber., 1892, 25, p. 445), or in small quantity by the action of nitrous acid on ortho-aminobenzoylphenylhydrazines (A. Konig and A. Reissert, Ber., 18 99, 3 2, p. 782), the chief product in this latter reaction being an isoindazolone: // CH2NHC6H5 /CH2NHC6H5 /CH2NC6H5 C6H4 - C6H4 - C6 H4 NH 2 HCI N :NCI N=N The best drawn series of the triazines is the symmetrical or cyanidine series, members of which result from the condensation of acid anhydrides with aromatic amidines (A. Pinner, Ber., 1892, 25, p. 1624): / NH NC?CsH 5 2C61 - 15 C +(CH 3 C0) 2 0 -> C6H5C N; NH 2 N :C?CH3 or by the condensation of aromatic nitriles with acid chlorides in the presence of aluminium chloride (Eitner and Krafft, Ber., 1892, 25, p. 2263). In using benzoyl chloride in this reaction the condensation is found to proceed better if a little ammonium chloride be added: 2C6H5CNd-C6H5.0001 C6H5 CCl OC C6H5 6 H 5 NC(C6H5):N The cyanidines behave as weak bases.
Mention may be made here of cyanuric acid, H3C3N303, which contains the same ring system as the cyanidines. It was first prepared by C. Scheele and is formed when urea HOC< NC-OH is strongly heated or when cyanuric chloride > N is treated with water. It is usually repre- "N :C -.OH sented by the inset formula and is closely related to cyanic acid and cyamelide, the relationships existing between the three compounds being shown in the diagram (see also A. Hantzsch, Ber., 1906, 39, p. 139): Ordinary temperature Cyamelide (CNOH) 3 Cyanic acid CNOH HO ions 1 High Cyanuric acid Decomposes with temperature
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Chisholm, Hugh, General Editor. Entry for 'Triazines'. 1911 Encyclopedia Britanica. https://www.studylight.org/encyclopedias/eng/bri/t/triazines.html. 1910.
