1,3,5-Triazines substitution

Triazines substituted with amines are generally less reactive as the amine becomes more basic, and more reactive as the amine becomes less basic. The chromophore may be sufficientiy electron withdrawing or donating to affect reactivity of the dye. 

Substituted derivatives of l-(tetrahydrobenzo[b]thiophen-2-yl-3-carboxylate)-5-phenyl-6-thio-l,2,4-triazin-4-one have been synthesized by heterocyclization reactions of different hydrazones obtained from 2-amino-tetrahydrobenzo[b]thiophene-3-carboxylate with phenyl isothiocyanate <00PS275>. Reaction of 5-methyl isothiosemicarbazide with a-amino acid vicinal tricarbonyl reactive substrates 1 and 2 yields 1,2,4-triazine substituted a-amino acids, as an equimolar mixture of regioisomers 3a/3b and 4a /4b, respectively <00JCS(P1)299>. 

Aliphatic hydrocarbons, triazine, substituted urea type and phenoxyacetic acid types of herbicides, Fluazifop and Fluazifop-butyl herbicides, ethylene diamine tetracetic acid salts in soil, aliphatic and polyaromatic hydrocarbons, phthalate esters, various organosulphur compounds, triazine herbicides, optical whiteners, mixtures of organic compounds and organotin compounds in non-saline sediments, aromatic hydrocarbons, humic and fulvic acids and mixtures of organic compounds in saline sediments and non-ionic surfactants and cobalamin in sludges. 

Another growing technique is super-critical fluid chromatography. Recent references to soil analysis include the following applications aliphatic hydrocarbons, polyaromatic hydrocarbons, polychlorobiphenyls, dioxins, alkyl and aryl phosphates, chloro, organophosphorus, triazine, substituted urea, phenoxy acetic acid, Dacthal herbicides and insecticides and mixtures of herbicides and pesticides and mixtures of organic compounds. 

Changing the nature of the triazine substitution pattern to the l,3,5-triazine-2,4-dione system leads to another series of herbicides, of which the best example is hexazinone (1) (75USP3902887). It is built up from cyanamide which is converted in several steps to the guanidine (2). Reaction with cyclohexyl isocyanate then gives an intermediate which can be cyclized to hexazinone (Scheme 2). 

Extensive studies on 1,2,4-triazines substituted with oxygen or sulfur in the 3- and 5-positions have shown that five distinct fragmentation patterns can be observed upon electron impact, but none involve initial loss of nitrogen. The following systems were studied l,2,4-triazine-3,5-diones (33), l,2,4-triazine-3,5-dithiones (74), 3-thioxo-l,2,4-... 

Burnet, M.W.M., O.B. Hildebrand, J.A.M. Holtum, and S.B. Powles (1991). Amitrole, triazine, substituted urea, and metribuzin resistance in a biotype of rigid ryegrass (Lolium rigidum). Weed Sci., 39 317-323. 

Table 6.4 shows first-order rate coefficients and tx/2 values for degradation of a number of pesticides in soils (Rao and Davidson, 1982). The k and t1/2 values calculated from field data are based on the disappearance of the parent compound (solvent extractable). Table 6.4 also includes k and t1/2 values calculated on mineralization (14C02 evolution) and parent-compound disappearance from laboratory studies. The t1/2 values were smaller for field than for laboratory studies. Rao and Davidson (1980) attribute this to the multitude of factors that can affect pesticide disappearance in the field while only one factor is studied in the laboratory. Rao and Davidson (1982) suggested that pesticides be classified into three groups based on values (Table 6.5) nonpersistent (t1/2 < 20 days), moderately persistent (20 < t1/2 < 100 days), and persistent (/1/2 > 100 days). Most chlorinated hydrocarbons are grouped as persistent, while carboxyl-kanoic acid herbicides are nonpersistent. The s-triazines, substituted ureas, and carbamate pesticides are moderately persistent. 

Herbicides that seem to have a single site of action on the photochemical pathway, which is associated closely with photosystem 11 are the chlorinated pheny 1 ureas, Ws-carbamates such as phenmedipham, chlorinated s-triazines, substituted uracils, pyridazinones, diphenylethers, 1,2,4-triazinones, azido-s-triazines, cyclopropane-carboxamides, p-alkylanilides, p-alkyl-thioanilides, aminotriazinones, and urea-carbamates (2). 

Substitutions at position 3 of the dihydrothiazine ring play a major role in the overall pharmacokinetic properties and toxicity. For example, the unusually long half-life of ceftriaxone appears to be caused by the presence of a triazine substituted at this position [62]. Cephalosporins such as cephalothin, cephalogly-cin, cephapirin, cephacetiile and cefotaxime share an acetoxymethyl group at the position 3 (Figure 2) and... 

Indeed, the promise of IA has led to workable enzyme-linked immunosorbent assays (ELISAs) for a variety of pesticides, including thiolcarbamates, triazoles and triazines, substituted ureas and sulfonylureas, bipyridilium compounds, and other groups of chemicals(2) (Table I). Additionally, radioimmunoassay (RIA) methods exist for chlorinated hydrocarbons, organophosphates, phenoxy adds and other chemical classes. 

In a similar way, by the action of sodium methoxide, both mono- and disubstitution reactions have been performed on 3,5-dimethyIthio-l,2,4-triazines substitution of the methylthio groups at C-5 and C-3 has been found to occur sequentially (Scheme 49) (73GEP2256604 75CCC2340 78HC(33)189). 

For the substitution of chlorine by 1,1-diethoxyethene to give a 1,3,5-triazine-substituted ketene acetal, see Houben-Weyl, Vol. 7/4, p 383. 

Ultraviolet spectra of 1,2,4-triazines substituted with different hetero substituents (amino, oxo, thioxo) are also published <83JOC1271,86JHC33,89RRC1321>. 

Gilbert and co-workers have reported the design and synthesis of triazine-substituted polyamines as drugs against... 

Adlington RM, Baldwin JE, Catterick D, Pritchard GJ (2001) The efficient, enandoselective synthesis of quinoxaline, pyrazine and 1,2,4-triazine substituted a-amino acids from vicinal tricarbonyls. J Chem Soc, Perkin Trans l(7) 668-679. doi 10.1039/B010134P... 

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