Triazines reaction with

Nucleophilic addition using organometallics showed that the C-4 position of (la) is a hard reaction site, whereas the C-5 position has soft reactivity (Equation (15)) <85CC1370>. These results are in accord with those from MO calculations. Softer nucleophiles such as organocopper reagents underwent a redox reaction with triazine to give 2,5-dihydro derivatives without ring substitution. 

Reaction with triazine (formation of complex cyclic thio/nitrogen compounds)... 

The literature reports also other methods for modification of lignocellulosic components to improve interphase adhesion. These comprise reactions with triazine derivatives [87], -octadecyl vinyl-sulfone [87], potassium permanganate [86, 88], as well as dicumil or benzoyl peroxides ([89] Jayamol [90]). Processing with peroxides in addition to significant improvement of mechanical properties of composites is also responsible for making processing of composite materials easier [86,91,92]. 

Reaction with a triazine derivative of cellulose Reaction with triazine derivatives of cellulose, carboxymethyl- Purification of alkaline phosphatase by immunoadsorption 101 ... 

Degradation of a herbicide by abiotic means may be divided into chemical and photochemical pathways. Herbicides are subject to a wide array of chemical hydrolysis reactions with sorption often playing a key role in the process. Chloro-j -triazines are readily degraded by hydrolysis (256). The degradation of many other herbicide classes has been reviewed (257,258). 

Furalazine, Acetylfuratrizine, Panfuran-S. Heating nitrovin in butanol or dimethylformamide at 100—130°C affords furalazine, 6-[2-(5-nitro-2-furanyl)ethenyl]-l,2,4-triazine-3-amine (34). An improved synthesis originates with 5-nitro-2-furancarboxaldehyde and acetone, proceeds through 4-(5-nitro-2-furanyl)-3-buten-2-one followed by a selenium dioxide oxidation to the pymvaldehyde hydrate, and subsequent reaction with aininoguariidine (35). Furalazine, acetylfuratrizine (36), and the A[-A/-bis(hydroxymethyl) derivative, Panfuran-S, formed from the parent compound and formaldehyde (37), are systemic antibacterial agents. 

The Boger pyridine synthesis involves the reaction of triazine 1 with activated alkene 2 in a hetero-Diels-Alder fashion. The intermediate bicyclic species 3 is unstable and a facile cycloreversion takes place due to the loss of nitrogen gas to afford the appropriately substituted pyridine derivative 4. 

Works on the oxidation of uric acid has unequivocally established the triazine structure > ° (9) of oxonic acid. This is further confirmed by the straightforward synthesis described by Piskala and Gut. ° The reaction of biuret (11) with potassium ethyloxalate yielded a potassium salt (24), that with ethyl oxamate, the amide of oxonic acid (25). Both these compounds were converted to 5-azauracil. An analogous reaction with diethyloxalate which should produce an ester of oxonic acid resulted in a mixture of urethane and parabanic acid, however. 

On reaction with aged phosphoroxychloride, 6-azauracil formed 3,5-dichlorotriazine (117) in only a 10% yield. " A somewhat higher yield (30%) was obtained from the reaction of 6-bromodioxotriazine which gave 3,5,6-trichloro-l,2,4-triazine. Similar reactions take place much more readily with uracil and in better yield. " Thus,... 

Dioxohexahydro-l,2,4-triazine (dihydro-6-azauracil) (128) yields a diacetyl derivative (129) which is relatively stable toward hydrolysis. The acetylation of the iV-methyl derivatives and the course of the reaction with diazomethane indicates that acetylation takes place here in positions 1 and 2 ... 

The catalytic effect of protons has been noted on many occasions (cf. Section II,D,2,c) and autocatalysis frequently occurs when the nucleophile is not a strong base. Acid catalysis of reactions with water, alcohols, mercaptans, amines, or halide ions has been observed for halogeno derivatives of pyridine, pyrimidine (92), s-triazine (93), quinoline, and phthalazine as well as for many other ring systems and leaving groups. An interesting displacement is that of a 4-oxo group in the reaction of quinolines with thiophenols, which is made possible by the acid catalysis. 

Mono-substitution occurs most readily in the stepwise replacement of the halogen substituents of 2,4,6-trichloro-s-triazine with aqueous methanol and sodium bicarbonate (30°, 30 min), the monomethoxy derivative (324) is obtained on heating (65°, 30 min), the disubstitu-ted derivative is formed and on brief heating (65°) with the more basic sodium carbonate or methanolic sodium hydroxide (25°, 3 hr) complete methoxylation (320) occurs. Ethanolic ethoxide (25°, 1 hr) or sodium carbonate (35°) is sufficient to give complete ethoxy-dechlorination. The corresponding phenoxy derivatives are obtained on treatment with one (0°), two (15°, 1 hr), or three equivalents (25-70°, 3 hr) of various sodium phenoxides in aqueous acetone. The stepwise reaction with phenols, alcohols, or thiols proceeds in better yield in organic solvents (acetone or chloroform) with collidine or 2,6-lutidine as acid acceptors than in aqueous sodium bicarbonate. ... 

C. Reaction with Electi ophiles Directed to Atoms of the 1,2,4-Triazine Ring. 268... 

The cycloaddition reaction of 1,2,4-tiiazines 7V-oxides proceeds differently from the reaction of the corresponding 1,2,4-tiiazines. Thus the 1,2,4-triazine 4-oxide 55 acts only as a diene in the reaction with 1 -diethylaminopropyne to afford 2-methyl-4-(dimethylamino)pyrimidines 111. At the same time the 1,2,4-triazine 4-oxides 55 react with l-(dimethylamino)-l-ethoxyethylene by 1,3-dipolar cycloaddition to give 5-methyl-1,2,4-tiiazines 112 (78CB240). 

The highly 7r-deficient character of the 1,2,4-triazine ring increases the nucle-ophilicity of the methyl group in methyl-1,2,4-triazine A-oxides in reactions with electrophilic alkenes and aldehydes. Thus treatment of the 6-methyl-3-phenyl-1,2,4-triazine 4-oxide 113 with l-(dimethylamino)-l-ethoxyethylene leads to the... 

The key step of an interesting synthesis of Sempervirine (327) is a triazine Diels-Alder annulation reaction with an enamine (88T3195). 1-... 

Phenylsulfonyl)indole 330 was converted to a ketone by a set of standard reactions followed by the selenium dioxide oxidation of the resulting acetyl goup to the ketoaldehyde 332 (Scheme 101). Methylthiosemicarbazide hydroiodide reacted with 332 to the triazine 333 in 83% yield. As Diels-Alder reactions with 1 -pyrrolidinocyclohexene failed, 333 was first oxidized... 

Because of the high polarity of the C=N double bonds, cyanuric chloride (120, R= Cl) is comparable with a carboxylic acid chloride. This explains its smooth reaction with diazomethane to yield dichloro-(diazomcthyl)-l,3,5-triazine (121, R = The analogous com-... 

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