Azole compounds

The analysis of azole compounds is becoming increasingly important. For the regulation of their residues, the multi-method Deutsche Forschungsgemeinschaft (DFG) S19 is used throughout Europe. Within the last few years, this method has been validated for many new azole fungicides in various crop matrices. The multi-residue method and the most important procedural details for the detection and determination of azole compounds are described below. Some important properties are shown in Table 1. 

Table 7 shows the structures of representative azole compounds and several structurally related compounds such as benzimidazoles, thiazoles and imidazolines. 

Aboul-Enein and Ali [78] compared the chiral resolution of miconazole and two other azole compounds by high performance liquid chromatography using normal-phase amylose chiral stationary phases. The resolution of the enantiomers of ( )-econazole, ( )-miconazole, and (i)-sulconazole was achieved on different normal-phase chiral amylose columns, Chiralpak AD, AS, and AR. The mobile phase used was hexane-isopropanol-diethylamine (400 99 1). The flow rates of the mobile phase used were 0.50 and 1 mL/min. The separation factor (a) values for the resolved enantiomers of econazole, miconazole, and sulconazole in the chiral phases were in the range 1.63-1.04 the resolution factors Rs values varied from 5.68 to 0.32. 

Inhibition of Copper Corrosion by Azole Compounds in Acidic Aqueous Solutions... 

Azole compounds, poly-N-vinylimidazole (PVI-1) and 2-undecylimidazole (UDI), are studied as alternative inhibitors to benzotriazole (BTA) for copper corrosion in aqueous systems using electrochemical techniques. It is shown that UDI, either as a cast film or dissolved in solution at concentrations as low as 7 X inhibits oxygen reduction on... 

Azole compounds such as benzotriazole, benzimidazole, indazole and imidazoles are efficient anti-corrosion agents for copper and copper-base alloys [1-10]. Many experimental techniques [11-15] have been used to study the corrosion inhibition mechanisms, however, the mechanisms are still not well understood. It is believed that the complex formation between copper and nitrogen atoms would inhibit oxygen adsorption on copper surface [16-20]. 

The procedure based on the reaction of the heterocyclic components offers the possible synthesis of numerous systems considering the diversity of accessible pyrazole and azole compounds, many of which are commercially available. 

One of the special features of azole compounds is the abundance of synthetic possibilities and therefore the abundant selection opportunities for biology and medicine. By examination of the properties of azole derivatives, one can recognize other applications for them apart from the control of fungi pathogenic to plants and man. Some of the azole derivatives, such as lombazole, exhibit... 

The N-vinyl-azole class, in which the 1-N atom of the azole is directly bonded to an sp2-hybridized carbon of a substituted olefin, belongs to the relatively recently synthesized subgroup of bioactive azoles. Compounds of this nature can be obtained by condensation of aldehydes with triazolyl-pinacolone resulting in a mixture of the E and Z isomers of the corresponding a, f3 -unsaturated ketones. Borohy-dride reduction easily converts these ketones into the corresponding alcohols (9)(Figure 16). 

In spite of the common mode of action, many other factors are significant for the successful use of individual azole compounds either for control of plant diseases or in the treatment of mycoses. Apart from the nature of the infection, the infection pressure, climatic conditions, the uptake of the fungicide by the plant, its transport and distribution within the plant, and plant compatibility are all important criteria in the complex interaction between pathogen, plant and fungicide. In medicine, high activity, good tolerance and optimal pharmacokinetic properties are prerequisites for therapeutic utility. 

In France and Germany, disease control measures on cereals are directed primarily against foot rot and leaf diseases, or leaf and ear diseases. In the United Kingdom, treatments are generally made for the control of leaf diseases, such as powdery mildew. It should be mentioned that these data do not include the use of the azole-compound triadimenol as a seed dressing for early season protection against powdery mildew and rust fungi on wheat and barley. 

Pivsa-Art, S. Satoh, T. Kawamura, Y. Miura, M. Nomura, M. Palladium-catalyzed arylation of azole compounds with aryl halides in the presence of alkali metal carbonates and the use of Cul in the reaction. Bull. Chem. Soc. 

The order of reactivity for the reaction sites of azole compounds in electrophilic reactions is known to be 5 >4> 2 [18]. Thus arylation at the relatively electron-rich 5-position may be regarded as similar to that of pyrroles, furans, and thiophenes (Scheme 1). In contrast, the reaction at the 2-position may be regarded as proceeding differently [3], Although the precise mechanism is still unclear, it may involve base-assisted deprotonative palladation with the ArPd(II) species (path d in Scheme 2). Insertion of the C=N double bond into the Ar-Pd bond is also a possi-... 

Scheme 2. Possible catalytic sequences for the Pd-catalyzed intermolecular arylation of azole compounds at the 2-position.

This may imply that the intermolecular coupling of various aryl halides with other heteroaromatic compounds may proceed. Indeed, it is now known that not only the special heteroaromatic halides but also usual aryl halides can react with a variety of five-membered aromatic heterocycles, including furans, thiophenes, and azole compounds such as M-substituted imidazoles, oxazoles, and thiazoles [133-137]. The arylation of azoles can be carried out using iodobenzoate immobilized on an insoluble polymer support [138]. Related intermolecular reactions of indole [139] and imidazole [140] derivatives have also been reported. 

Chan-Tompkins, N.H. Babinchak, T.J. Cardiac arrhythmias associated with coadministration of azole compounds and cisapride. Clin. Infect. Dis. 1997, 24 (6), 1285-1313. 

Application of Molecular Orbital Calculations To Estimate the Active Conformation of Azole Compounds... 

Molecular orbital calculations were introduced to estimate the active conformations of azole compounds at an enzyme active site. The computed data were discussed referring to the spectroscopic information and utilized for the steric fit evaluation. 

To estimate the conformations of (I) and (II) at the enzyme active site of fungi or plants, IR and H-NMR spectra of the azole compounds in solutions were measured. From the results of mode of action and binding assay, (I) and (II) are considered to locate in the close proximity to the prosthetic porphyrin group of cytochrome P-450 enzymes. The polarity of macromolecules close to the porphyrin moiety of apohemog1obin has been determined by fluorescence study to be similar to that of n-octanol (1 0)> In our study, carbon tetrachloride and deuterioch1 oroform of which polarities were similar to that of n-octanol were used. 

Figure 3 The sites of inhibition by azole compounds in the ergosterol and gibberellin biosynthesis.

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