Alkyl-substituted 1,2,4-triazines

The parent 1,2,4-triazine has two absorption bands in methanol, at 374 (a = 400) and 247.8 nm (3020). In O.IN HCl/methanol only one band is observed, at 230 nm (e = 4460), while in O.IN NaOH/methanol bands at 382 nm (380) and 249.5 nm (3430) were found <68CB3952>. In the gas phase this compound has several bands in the region between 420 nm and 380 nm <75TH 611-0l>. Alkyl-substituted 1,2,4-triazines show similar electronic spectra <59JCS1240,59JCS1247>. 

Most 1,2,4-triazines are crystalline compounds, the melting points depending on the structure and the substituents present. Alkyl-substituted 1,2,4-triazines are yellow and melt at low temperatures, or in a few cases they are liquids at room temperature but they are reasonably stable. They can be stored at 0°C or lower, but in time they become dark. They can usually be distilled under reduced pressure, and can be purified by vapor-phase chromatography, by which isomeric alkyl-1,2,4-triazines can be separated. Aryl-substituted 1,2,4-triazines have melting points around 100°C, while all heterosubstituted (oxo, thioxo, amino, etc.) 1,2,4-triazines have melting points in the 200 °C region. These compounds are usually very stable. 

Alkylation of pyrano[2,3-z7]-l,2,3-triazine 203 with a number of electrophiles in 15% potassium hydroxide/acetone solution gave the substituted triazines 204 in a remarkably consistent 55% yield (Equation 18) <2003MI1061>. 

The reaction of monosubstituted glyoxals (455) with aminoguanidine (460a) has been extensively studied. Either 5- or 6-substituted 3-amino-1,2,4-triazines can be obtained depending on the reaction conditions. N-Alkyl-substituted aminoguanidines with 1,2-dicarbonyl compounds condense to give 3-alkylamino-l,2,4-triazines, while... 

Clearly terbufos, the first entry in the Table, is the most persistent with a T. <- of more than 35 days. Alkyl substitution on the carbon between the sulfur atoms of those molecules containing a nitrile group increases the soil persistence. Still, none are as persistent as terbufos. Therefore, the presence of a nitrile in these molecules, as was previously discussed for the Atrazine/ Bladex-triazine relationship, decreases the soil persistence of these organophosphorodithioates compared to terbufos. 

X-ray crystallographic data are also available for 1,2,3-benzotriazines 3 and 12 15 and other condensed 1,2,3-triazines 16-19. Since a structure determination of the unsubstituted or alkyl-substituted 1,2,3-benzotriazines is not yet available, comparison with the monocyclic compounds is not possible. 

V-Alkyl-substituted guanidin-2-amines condense with 1,2-dicarbonyl compounds to give A -alkyl-l,2,4-triazin-3-amines 7 and 8.115 6-Substituted 1,2,4-triazin-3-amines 7 can also be prepared by reaction of 2-(hydroxyimino)-l-phenylethan-l-onen5 or dibromo ketones with guanidin-2-amine.141 24 2... 

Alkyl-substituted 1,3,5-triazines 1 readily condense with aldehydes or alkyl nitrites 2 in the presence of base to yield the corresponding alkenyl-substituted triazines16Houben-Weyl, Vol. E14b, Part 1, p 297). 

The acid-catalyzed chlorination or bromination of alkyl-substituted 1,3,5-triazines produces exclusively the a-haloalkyl-substituted 1,3,5-triazines. Nuclear halogenation is not observed under the applied conditions. The reactions are preferably conducted in glacial acetic acid in the presence of sodium acetate at a temperature between 55-60CC and with elementary... 

Thienyl-4,6-diamino-l,3,5-triazines 94 with three flexible alkyl chains at one end of the elongated rodUke core, terminated by a rather bulky polar 4,6-diamino-1,3,5-triazine apex at the opposite end (Fig. 5.32) form micellar cubic phases. It is remarkable that such molecules with such a long aromatic unit and the bulky 4,6-diamino-substituted triazine apex, both contributing to a truncated shape with relatively small cone angles, are still able to form micellar cubic phases instead of... 

Dichloro-s-triazine and its 6-alkyl analogs are as easily hydrolyzed by water as trichloro-s-triazine and, on suspension in aqueous ammonia (25°, 16 hr), the first is diaminated in good yield. 2,4-Bistrichloromethyl-6-methyl- and -6-phenyl-s-triazines (321) require a special procedure for mono-alkoxylation (0-20°, 16 hr, alcoholic triethylamine) disubstitution occurs at reflux temperature (8 hr). Aqueous triethylamine (100°, 3 hr) causes complete hydroxy-lation of 2,4,6-tris-trichloromethyl-s-triazine which can be mono-substituted with ammonia, methylamine, or phenoxide ion at 20°. 

Pyridine A-oxides were converted to tetrazolo[l,5-a]pyridines 172 by heating in the presence sulfonyl or phosphoryl azides and pyridine in the absence of solvent <06JOC9540>. 3-R-5-Trinitromethyltetrazolo[l,5-a]-l,3,5-triazin-7-ones 173 have been prepared from the alkylation of 5-trinitromethyltetrazolo[l,5-a]-l,3,5-triazin-7-one silver salt with different alkylation agents <06CHE417>. The use of 2-fluorophenylisocyanide in the combinatorial Ugi-tetrazole reaction followed by a nucleophilic aromatic substitution afforded tricylic tetrazolo[l,5-a]quinoxaline 174 in good yields and with high diversity <06TL2041>. 

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