1.2.4- Triazole compounds

The lH-l,2,4-triazole compounds possess important pharmacological activities such as antifimgal and antiviral activities [18-20]. In the present study, the reactive intermediates 45a-c, prepared in situ from the dichlorides 44a-c, were reacted via the cycloaddition reaction with ethyl cyanoacetate 40 to give, after spontaneous rearrangement, the triazole hydrazides 41a-c. These compoimds were used as starting materials for the synthesis of the... 

Crabb et al. found <1997J(P2)49> that treatment of the triazole compound 444 - easily available from pyrimidi-nylhydrazine by treatment with arylisocyanates - with DCC gives rise to the triazolopyrimidinium aminide 445. 

The most widely used method for the ring closure to the title ring system is the reaction of a 3-mercapto-4-amino[l,2,4]triazole compound with an a-halo-oxo reagent. The particular realizations of these syntheses are summarized in Table 4. Comparison of the reference lists shows that reactions with phenacylhalogenides and analogues (entry 1) is by far the best method. Synthesis of altogether more than 150 derivatives are described in... 

Incorporation of a triazole ring into a compound is a known strategy for increasing thermal stability. Many triazole compounds show high thermal stability coupled with a low sensitivity to shock and impact. 2,6-Dipicrylbenzo[l,2-d/][4,5-[Pg.307]

In the reactions with phosphonio-a-methoxycarbonyl-alkanides, the products of type 261 derived from 1,3-cycloaddition can rearrange to the tautomeric lif-pyrazolo-triazole (87MI2). The reaction of 3-diazopyra-zoles and 3-diazoindazole with acyl-substituted phosphonium ylides led to pyrazolo-triazine and indazolo-triazine derivatives 266 instead of the expected triazole compounds (8IJHC675). In this case, the ylides, which can exist as phosphonium enolates, possess nucleophilic and electrophilic centers in a /8-relationship, giving [7 + 2] or [11 -I- 2]cycloaddition reactions. With dimethylsulfonio-a-aroyl-methanides, very complex, temperature-dependent mixtures were obtained, in some cases with sulfur retention (87MI3). 

Partially or fully reduced triazoles are relatively unstable and have not aroused great interest except for those with exocyclic double bonds, which retain the potential aromatic character of the parent triazole. Compounds such as triazolinone (2) and 3,5-dioxo-l,2,4-triazolidine (urazole) (3) will be treated as triazoles, since they can be written in the tautomeric triazole forms (2a) and (3a) (Equations (2) and (3)). 

Azole antifungal drugs are synthetic compounds with broad-spectrum fungistatic activity. Azoles can be divided into two groups the older imidazole agents, in which the hve-member azole nucleus contains two nitrogens, and the newer triazole compounds, fluconazole and itraconazole, in which the azole nucleus contains three nitrogens. 

To improve the lightfastness of dyes used to color car fittings, benzophenone or triazole compounds are often employed in the dyebath or as aftertreatment [140],... 

Table 2. Antiviral Activity and hERG Channel Activity for Key Triazole Compounds ...

While triazole compounds are not often energetic enough and pentazole species are kinetically too labile, the tetrazole derivatives often combine the desired endo-thermicity with kinetic stability (Fig. 9.7). Aminotetrazole (AT) and diaminotetraz-... 

The few known triazole (17) compounds are of different type. MnS04 forms a mono species under conditions where Ni forms a tris, and this has a monomeric structure95 [Mn(S04)(H20)L]. On the other hand Mn(NCS)2 forms a polymeric Mn(NCS)2 2L species, in which the polymerization occurs through the triazole ligand (N-2 and N-4) bridging trans Mn(NCS)2 units.96 The other known triazole compound is Mn2(NCS)4(4-Me-triazole)5 which has97 the dimeric structure (19)... 

As early as 1888 von Pechmann, assistant to von Baeyer, prepared the 1,2,3-triazole compound (6) as well as some derivatives, and correctly characterized his newly invented azole heterocycles as 1,2,3-triazoles (1888CB2751). In a 1950 review it was stated that more than 1400 1,2,3-triazoles had been described in the literature, and in the period 1973-1980 Chemical Abstracts reported more than 9000 studies involving 1,2,3-triazoles. 

Since their discovery in the late 1960s several compounds from the chemical class of 1-substituted imidazoles and 1,2,4-triazoles have been developed and successfully used for the control of plant diseases and for the treatment of human fungal infections. The first commercial triazole compound was triadimefon ( 1J, introduced by Bayer in 1973 for the control of powdery mildew, rusts, and seed-borne diseases of cereals. Since that time many other so called "azole-fungicides" have been introduced into crop protection (2) and others are still being developed. 

Replacement of the phenol with a triazole was also explored [94]. Several highly potent ER 3-binding ligands were identified as exemplified by analogs 77 and 78, although, in general, the triazole compounds showed somewhat lower ER affinity as... 

This ring system was first prepared, in 1985, by ring closure of the diaroylamino-bromomethyl-[l,2,3]triazole compound (43) (Equation (6)) <85JCS(Pl)ll67). A related procedure leading from (45) to the 0X0 derivative (46) was published two years later, in 1987, by the same group (Equation (7))... 

The 3-phenacylthio-4-amino[l,2,4]triazole compound (39) proved to be a suitable starting material for the synthesis of [l,2,4]triazolo[l,2,4,5]dithiadiazines <90Mi 82i-0i>. With isocyanate the arylimino product (40) was obtained, whereas carbon disulfide afforded the thione derivative (41). 

Monomers containing the triazole unit are shown in Figure 9.1. The synthetic routes to get 1,2,3-triazole compounds are reviewed in the literature. ... 

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