Imidazole and its derivatives

Glyodin is a foliage fungicide with a curative effect against apple scab. It is effective also against cherry anthracnose and leaf spot. The pure compound is not phytotoxic, but the technical product damages certain plants. This phytotoxicity is attributed to the oleic acid contamination of stearic acid. 

The mode of action of glyodin is presumably its effect on the biosynthesis of purine, of which it is the competitive inhibitor. Indeed, the fungitoxicity of glyodin can be eliminated with guanine and xanthine (West and Wolf, 1955). 

Imazalil can be prepared by the reduction of the intermediate product (II), formed in the reaction of chlorophenacyl bromide (9) with imidazole (10), and subsequent alkylation with allyl chloride (6) (Godefroi and Schuermans, 1970). 

Several related derivatives of imazalil (miconazole, econazole) show in vitro a broad antimicotic spectrum against fungi pathogenic to man and animals (Buchenauer, 1977c). 

Of the 1-carbamoyl imidazole derivatives The Boots Company found the compounds BTS 40 542 to be the most potent fungicide (Birchmore et al., 1977). The scheme of preparation of prochloraz is the following (Brookes et al.. 1973)  

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Imidazole and its derivatives form an interesting and important class of hetero cyclic aromatic amines Imidazole is approximately 100 times more basic than pyndme... 

Kirk and Cohen (1969, 1971, 1973 Kirk et al., 1973) successfully applied the photo-fluoro-de-diazoniation method for the introduction of fluorine into imidazole and its derivatives with various substituents (e.g., histidine) 2- and 4-fluoroimi-dazole had not previously been synthesized by other methods. 2-Fluoroimidazole, in contrast to the 4-isomer, is easily hydrolyzed in water (Kirk et al., 1973). 

Imidazole and its derivatives continued to play an important role in asymmetric processes. Optically active pyrroloimidazoles 26 were prepared by the cycloaddition of homochiral imidazolium ylides with activated alkenes <96TL1707>. This reaction was used in the enantioselective preparation of pyrrolidines <96TL1711>. A review of the use of chiral imidazolidines in asymmetric synthesis was published <96PAC531> and the preparation and use of a new camphor-derived imidazolidinone-type auxiliary 27 was reported < 6TL4565> <96TL6931>. 

Imidazole and its derivatives revealed yet another binding modality. In imidazole both a hydrogen bond donor and an acceptor are present on the opposite sides of the molecule, and this relatively strong base can elicit some proton transfer with the... 

Very recently, the kinetics and thermodynamics of a variety of axial ligation reactions have been investigated with Fe11 and Co11 porphyrins involving the small molecules CO, 02, and NO as ligands 27-30, 40, 92, 93). These experiments lead to the conclusion that the dynamic trans effects observed in these systems cannot alone be explained by the interaction models D and F (Fig. 1). Especially imidazole and its derivatives do not hold the place in various series of trans effects that they should take on the ground of their proton basicities. Therefore, besides their usual a-donor-tr-acceptor function, these unsaturated molecules are ascribed an additional 7r-donor function. 

Another type of curing agent of technological importance is imidazole and its derivatives which can promote base-catalysed homopolymerisation of epoxide. However very few DSC studies have been reported on well-defined systems based on imidazoles. 

Only very few among the common amino acids possess a pK within the range 5.8-7.0. Therefore, the imidazole ring of histidine was suspected very early to represent the group responsible for nucleophilic attack on the substrate (38). The pK of free imidazol is 6.9 (39) that of imidazol, contained in histidine or its peptides, varies between 5.6 and 7.1 (40). Imidazol is well known to form unstable acyl derivatives, which undergo spontaneous hydrolysis because of the presence of the resonating triad unit —-N—C= N— (41). In addition, imidazol and its derivatives catalyze the hydrolysis of certain esters, especially those derived from phenols (42). Likewise, the behavior of imidazol towards thio esters reflects exactly the specificity of ChE s (see IV, 4). Thus, thiol esters are split (43), whereas thiono esters are resistant (21). 

Hoffman K (1953) Imidazole and its derivatives, Part 1. In Weissberger A (ed) The chemistry of heterocyclic Compounds. Interscience, New York... 

Hydrogen bonding of the type N-H N formed between molecules of imidazole and its derivatives is closely related to a variety of biological systems and has been a subject of extensive studies using a variety of spectroscopic and diffraction techniques. In crystalline imidazole, the molecules form a one-dimensional chain of intermolecular N-H N hydrogen bonding, a schematic representation of which is shown below. 

A comprehensive monograph on imidazole and its derivatives by K. Hofmann1 was published in 1953. A chapter dealing with imidazoles and condensed imidazoles by Schipper and Hay2 in Heterocyclic Compounds edited by Elderfield reviewed the literature to 1955, while a more recent review by Pozharskii et al.3 brought the chemistry of imidazole and some important condensed imidazoles up to date to 1964. A number of monographs on the chemistry of heterocyclic compounds4-10 have also dealt with aspects of imidazole chemistry in a necessarily brief manner. Specific topics in imidazole chemistry and biochemistry have been covered in further reviews.11-21 In the most... 

When the ring has no polar substituents the dipole moments of imidazole and its derivatives are of the order of 3.8-4.0 D.163-165 A nitro substituent in a condensed ring increases this value by 2.0-2.5 D,166 whereas A-arylation lowers the dipole moment due to conjugation of the imidazole and aryl rings.167 Further measurements168 (from dielectric data in benzene at 25°C) have shown that in N-arylimidazoles, the phenyl ring is out of the plane of the imidazole... 

There has been considerable interest in the measurement of the dipole moments of imidazole and its derivatives since the values obtained should provide valuable information about the structures of the molecules (70AHC 12)103, 80AHC(27)24l, 66RCR122). 

The results of halogenations of imidazole and its derivatives have provided a host of complicated but mechanistically interesting results. 

K. Hofmann, in The Chemistry of Heterocyclic Compounds. Imidazole and its Derivatives, Part I (cd. A. Weissbuiger). Interscience, New York, 1953. 

Hoffmann, "Imidazole and Its Derivatives , Interscience,NY(1953), 141—2 (One of the monographs on the Chemistry of Heterocyclic Compounds, edited by A.Weissberget)... 

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