1,2,3-Triazine, tris-dimethylamino

Perhaps the most firmly based report for the formation of an azete involves flash pyrolysis of tris(dimethylamino)triazine (303). This gave a red pyrolysate believed to contain the highly stabilized azete (304) on the basis of spectroscopic data. The putative azete decomposed only slowly at room temperature, but all attempts to trap it failed (73AG(E)847). Flash pyrolysis of other 1,2,3-triazines gives only acetylenes and nitriles and it is not possible to tell whether these are formed by direct <,2-l-<,2-l-<,2 fragmentation of the triazine or by prior extrusion of nitrogen and collapse to an azete (81JCR(S)162). 

Under flash vacuum thermolysis (FVT) the 1,2,3-triazine (32) was readily thermolyzed to an alkyne, a nitrile, and nitrogen in high yields. For unsymmetrically substituted 1,2,3-triazines as FVT substrates, fragmentation proceeded selectively a bulky substituent at C-4(6) made the adjacent C—N bond break more easily than the opposite C—N bond. The FVT method was applied to the synthesis of the fluorinated alkynes, perfluoro-3-methyl-l-butyne and difluoroethyne [(33), R = (CF3)2CF, F] (Equation (1)) (89CC1657, 91CC456). It has been claimed, however, that tris(dimethylamino)-1,2,3-triazine forms the monocyclic azete. 

Most 1,2,4-triazines are very stable thermally. Only a few data on their thermolytic behavior are therefore to be found in the literature. We observed a few years ago that triphenyl-1,2,4-triazine (349) can be refluxed in an open tube at 550 °C without extensive decomposition. When the tris(dimethylamino) compound (350) was heated at 650 °C the colorless starting material was isolated (76UP21900). 

The FVT method can be applied for the synthesis of the fluorinated alkynes, perfluoro-3-methyl-l-butyne and difluoroethyne 40 (R = (CF3)2CF, F) (Scheme 3) <1989CC1657, 1991CC456>. It has been claimed, however, that tris (dimethylamino)-l,2,3-triazine forms the monocyclic azete. 

Gompper and his coworkers treated tris(dimethylamino)cyclopropenium cation with potassium azide and obtained a 1,2,3-triazine. They assumed that this reaction proceeds via a benzvalene-type intermediate (156) 170) ... 

The pioneering work of Seybold et al. led to the first isolable unfused azete (30) by the FVT of tris(dimethylamino)triazine (29) (Equation (9)) <73AG(E)847>. The EVT of 4-phenylbenzotriazine... 

H NMR spectra of 1,3,5-triazines are otherwise straightforward. The chemical shifts of substituents appear as expected and are readily assigned from known published data. In this context aspects of H NMR applied to 1,3,5-triazines are discussed rather than listings of chemical shifts of substituents attached to 1,3,5-triazines. An investigation of the possible impurities in hexa-methylmelamine (2,4,6-tris(dimethylamino)-l,3,5-triazine, HMM) involved a H NMR analysis of HMM, cyanuric acid (1), and several potential impurities, namely 2-chloro-4,6-bis(dimethylamino)-... 

The Cotton-Mouton effect, magnetic anisotropy, and charge localization of 2,4,6-tris(dimethyl-amino)-1,3,5-triazine compared with 1,3,5-triazine have been examined <91JST(248)20l>. Dilute solution Kerr and Cotton-Mouton constants were measured for both 1,3,5-triazine and 2,4,6-tris(dimethylamino)-l,3,5-triazine. These constants were then used to derive experimental values for the optical-frequency polarizability anisotropies, and more importantly the magnetic anisotropies of... 

Tris(dimethylamino)-l,3,5-oxadiazinium chloride (223) was obtained when dimethyl-cyanamide and dimethylcarbamoyl chloride were heated together at 170°C for 20 min. When the salt (223) was heated with concentrated ammonia the l,3,5-triazin-2-one (224 R = H) was the product. The suggested mechanism follows the ANRORC pathway. The triazine product (224) can also be prepared more simply by hydrolysis of 2-chloro-4,6-bis(dimethylamino)-l,3,5-triazine by IM hydrochloric acid at boiling point for 3 h (Scheme 69) <85JCS(P1)1533> and 2-chloro-4,6-bis(dimethylamino)-l,3,5-triazine is available from cyanuric chloride and dimethylamine. The salt... 

The thermally induced rearrangements with loss of dimethylamine, of 2-alkylamino-2,4,6-tris(dimethylamino)-277-l,3,5-oxadiazines (55) to 4,6-bis(dimethylamino)-l,3,5-triazin-2(177)-ones (57) have been reported <85JCS(P1)1533>. 

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