1 -Benzoyl-3-phenyl-1,2,4-triazole

The influence of protein denaturants (such as alcohols, urea and urea derivatives, and quaternary ammonium salts) on the stability of the compact-coil conformation of PMAA is also described. These protein denaturants, when added to aqueous solutions of PMAA, considerably limit the rate of the neutral hydrolysis of 1-benzoyl-3-phenyl-1,2,4-triazole. 

Other non-traditional preparations of 1,2,3-triazoles have been reported. The rearrangement in dioxane/water of (Z)-arylhydrazones of 5-amino-3-benzoyl-l,2,4-oxadiazole into (2-aryl-5-phenyl-27/-l,2,3-triazol-4-yl)ureas was investigated mechanistically in terms of substituents on different pathways <06JOC5616>. A general and efficient method for the preparation of 2,4-diary 1-1,2,3-triazoles 140 from a-hydroxyacetophenones 139 and arylhydrazines is reported <06SC2461>. 5-Alkylamino-] //-], 2,3-triazoles were obtained by base-mediated cleavage of cycloadducts of azides to cyclic ketene acetals <06S1943>. Oxidation of N-... 

The role of substituents X on the mononuclear heterocyclic rearrangement (MHR) of 20 phenylhydrazones 54 of 3-benzoyl-5-phenyl-l,2,4-oxadiazole into the triazoles 55 (Equation 2) has been investigated, allowing the influence of X on the product distribution to be evaluated and first-order rate constants and Hammett correlations to be determined <1999T12885>. 

Not surprisingly, it is rather difficult to separate the different contributions of the different interactions as they occur in the micellar Stern region. In an attempt to solve this problem, the group of Engberts used a series of hydrolysis reactions of activated esters and amides to probe the reaction environment offered by micelles. The reactions initially involved the water-catalyzed pH-independent hydrolysis reactions of i-methoxy-phenyl dichloroacetate 4 and l-benzoyl-3-phenyl-l,2,4-triazole 5, as extensive information on the rate retarding effects of added cosolutes on this reaction was available. ... 

Thermolysis of 2-phenyl-A-benzoyl-4,5-dimethyl-l,2,3-triazol-l-imine (125) in refluxing DMSO gives 2-phenyl-4,5-dimethyl-1,2,3-triazole (126) and jV,A -diphenylurea (Scheme 20) <92JOC2252>. 

A number of general methods for the synthesis of meso-ionic 1,2,4-triazol-3-ones are available. Sodium ethoxide-catalyzed cyclization of 1-benzoyl-l,4-diphenylsemicarbazide (201, R = R = R = Ph, X = O) yielded anhydro-3-hydroxy-1,4,5-triphenyl-1,2,4-triazolium hydroxide (200, R = R = R = Ph). A general route to meso-ionic 1,2,4-triazol-3-ones (200) is exemplified by the formation of the 1,4,5-triphenyl derivative (200, R = R = R = Ph) from A-amino-MA -diphenylbenzamidine (202, R = R = R = Ph) and phosgene. In contrast with this ready meso-ionic compound formation, the corresponding reaction of the iV-methylbenzamidine (202, R = Me, R = R = Ph) did not yield the meso-ionic 1,2,4-triazol-3-one (200, R = Me, R = R = Ph). The product was in fact 3,4-diphenyl-2-methyl-l,2,4-triazol-5-onium chloride (203), which on heating gave 3,4-diphenyl-1,2,4-triazol-5-one (204, R = Ph). The formation of the A-methyl derivative (200, R = Me, R = R = Ph, yield 79%) by heating the 7V-thiobenzoyl semicarbazide (201, R = Me, R = R = Ph, X = S) with potassium carbonate in methyl cyanide has been reported. Another synthesis of A-methyl derivatives (200, R = Me) involves methylation of 3-methyl-4-phenyl-l,2,4-triazol-5-one (204,... 

Reaction of a-hydrazinoheterocycles with 4-(hydroxymethylene)-2-phenyl-5(4//)-oxazolone 406 gives rise to A-benzoyl-ot-(heteroaryl)glycinates 563 containing a fused 1,2,4-triazole after oxidative cyclization (Scheme 7.178). ... 

Wheeler and Beardsley59 were able to prepare the substituted 1,2,4-triazoles (34) by reaction of 2-methyl-l-benzoyl-2-thiopseudoureas (33) with phenyl hydrazine. Similarly, Davidson60 treated hydrazine with... 

It is interesting to note that 3,5-diphenyl-l,2,4-oxadiazole (155) undergoes a slow ring cleavage on irradiation in ether, giving benzoyl-benzamidine (156) and 2-phenyl-4-quinazolone (157) as major products.140 Ring cleavage also occurs in 1,2,5-oxadiazoles, 1,2,5-thia-diazoles, and 25-1,2,3-triazoles.141... 

G2N3 N N N C c l,3-Dimethyl-4-(l,2,3-triazolyl)sulfide 3-methyl-2-phenyl-l,2,3-triazol-l-ine-4-thione 2-(4-chlorophenyl)-4-amino-5-benzoyl-l,2,3-triazoleaf... 

Similarly, the 2-azidoethylene-l,l-dicarbonitriles (92) were found to react with aniline to give the corresponding anilino derivatives 121 Reaction of phenyl ethynyl ketone with sodium azide in an aqueous medium, it will be recalled, gave the isoxazole 74 (R = H). When this reaction was carried out in dimethylformamide, quite different results were found in this case the sodium salt of 4-benzoyl-1,2,3-triazole was isolated in good yield . The formation of this product... 

JCS(P1)927>. In dioxane water, (Z)-aryl hydrazones of 3-benzoyl-5-phenyl isoxazole (77) is rearranged into phenacyl triazole (78) (Equation (14)) <87JCS(P2)537, 88JCS(P2)1683>. Aryl hydrazones of 5-phenacyl isoxazoles (79) is rearranged into the 5-oxidopyridazinium betaines (81) via the intermediate (80) (Scheme 13) <83TL1285>. 

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