1.2.3- Triazole-4-carboxylic acid

Intramolecular cycloaddition between an azide and an unsaturated ester (see 300) was the key step in the synthesis of triazole carboxylic acids 302 a, b, prospective anionic sugar mimics (Eq. 33) [79]. 

Ribavirin is reversibly phosphorylated by all nucleated cells. It is also metabolized in the liver to a triazole carboxylic acid metabolite that is eliminated in the urine along with the parent compound. The plasma half-life of ribavirin is 9.5 hours when it is administered by aerosol (2.5 hours/day for 3 days), whereas its half-life is around 12.5 days at steady state. The drug accumulates in erythrocytes, with a half-life of 40 days. 

Patent One Step Synthesis of 1,2,3-Triazole Carboxylic Acids... 

Utility Improved Method for Preparing 1,2,3-Triazole Carboxylic Acid... 

The positive charge on nitrogen atom two will cause the triazole ring to act as a strong electron-attracting group. This idea has been confirmed by measurements of the dissociation constants of the triazole carboxylic acids, which have shown (see Table IV, p. 121) that acids... 

Amino-l,2,4-triazole has been prepared by evaporating formylguanidine nitrate with sodium carbonate, and from 5(3)-amino-1,2,4-triazole carboxylic acid-3(S) by heating above its melting point, or by a long digestion with acetic acid. ... 

Triazole-l-carboxylic acid, 4-aryloxy-, ethyl ester... 

Triazole-4-carboxylic acid, 5-chloro-1-phenyl-UV, 5, 685 (55JA6532)... 

Pyrazolo[3,2-c][l,2,4]triazole-7-carboxylic acid synthesis, 6, 1018 Pyrazolotriazoles dye releasers... 

Triazole-4-carboxylic acid, 2-phenyl-cleavage reactions, 5, 697... 

Triazole has been prepared by the oxidation of substituted 1,2,4-triazoles, by the treatment of urazole with phosphorus pentasulfide, by heating equimolar quantities of formyl-hydrazine and formamide, by removal of the amino function of 4-amino-l,2,4-triazole, by oxidation of l,2,4-triazole-3(5)-thiol with hydrogen peroxide, by decarboxylation of 1,2,4-triazole-3(5)-carboxylic acid, by heating hydrazine salts with form-amide,by rapidly distilling hydrazine hydrate mixed with two molar equivalents of formamide, i by heating N,N -diformyl-hydrazine with excess ammonia in an autoclave at 200° for 24 hours, and by the reaction of 1,3,5-triazine and hydrazine monohydrochloride. ... 

Phenylmethyltriazole Carboxylic Acid. —The mother substance of this compound is a triazole, viz., pyrro-n/ d-diazolc, which is one of four isomeric compounds ... 

In addition to CDI, just as in the family of the carboxylic acid azolides (see the preceding Section), changes in the azole units have permitted preparation of a whole series of CDI analogues with graduated reactivities A V7 -carbony ldipyrazole,[311 NJVf-carbonyldi-1,2,4-triazole,[32] as well as Af,Af -carbonyldibenzimidazole and A /V -car-bonyldibenzotriazole.t33]... 

In analogy to the reaction of CDI with carboxylic acids, the even more reactive NJf -carbonyldi-1,2,4-triazole 5bl has been used instead of CDI in cases where specific structural effects require a higher reactivity of the azolide. On the other hand, the example of the last paragraph of the preceding section showed that A -carbonyldi-benzimidazole 151 141 and AyV -carbonyldibenzotriazole 151 have been useful for the syntheses of azolides with reduced reactivities when these are essential and sufficient for the specific reaction in question. 

The following compilation shows the results of a reaction sequence consisting of the conversion of carboxylic acids by A -oxalyldiimidazole (A) or A -oxalyld 1,2,4-triazole) (B) into the corresponding azolides followed by acid-catalyzed reaction with alcohols to give the appropriate esters.tl38]... 

In analogy to the formation of thiolesters, some selenolesters have also been synthesized from carboxylic acid, phenylselenol, and A -carbonyldi-1,2,4-triazole.tl80]... 

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