Nitroimidazoles structure

Chemical Name l-Methyl-2-(l-methylethyl)-5-nitro-lH-imidazole Common Name 2-Isopropyl-l-methyl-5-nitroimidazole Structural Formula ... 

Chloro-l-methyl-4-nitroimidazole (204) was also used as a heterocyclic component in the Turpin reaction. Intermediate 205 was formed under mild conditions and its cyclization was achieved by heating with ethanolic dimethylamine in a sealed tube to give a blue-colored substance, which was attributed structure 206 (Scheme 32) (52JCS784). 

Leiros HKS, Kozielski-Stuhrmann S, Kapp U, Terradot L, Leonard GA, McSweeney SM (2004) Structural basis of 5-nitroimidazole antibiotic resistance. J Biol Chem 279 55840-55849... 

Their antibacterial and mutagenic activity is closely related to the reduction of the 5-nitro group, which is common to all nitroimidazole drugs, and the subsequent formation of reactive metabolites that bind to bacterial DNA, inhibiting DNA and protein synthesis in the microorganisms. Metabolism of 5-nitroimidaz-oles in mammals usually leads to covalently bound residues with a persistent imidazole structure. 

Adams GE, Flockhart IR, Smithen CE, Stratford IJ, Wardman P, Watts ME (1976a) Electron-affinic sensitization. VII. A correlation between structures, one-electron reduction potentials, and efficiencies of nitroimidazoles as hypoxic cell radiosensitizers. Radiat Res 67 9-20... 

Stillman MJ, Shaw CF III, Suzuki KT (1992) Metallothioneins. Synthesis, structure, and properties of metallothioneins, phytochelatins and metal-thiolate complexes. VCH Publishers, New York Stratford IJ, Hoe S, Adams GE, Hardy C, Williamson C (1983) Abnormal radiosensitizing and cytotoxic properties of ortho-substituted nitroimidazoles. Int J Radiat Biol 43 31-43 Stubbe J, Kozarich JW (1987) Mechanisms of bleomycin-induced DNA degradation. Chem Rev 87 1107-1136... 

Chemical Name N-p-Ethylmorpholino-(5)-nitroimidazole Common Name Nitrimidazine Structural Formula ... 

Chemical Name l-[2-(Ethylsulfonyl)ethyl]-2-methyl-5-nitroimidazole Common Name -Structural Formula ... 

Kim P, Kang S, Boshoff HI et al (2009) Structure-activity relationships of antitubercular nitroimidazoles. 2. Determinants of aerobic activity and quantitative structure-activity relationships. J Med Chem 52 1329-1344... 

The product from the reaction of citraconic acid (or its anhydride) with nitric acid was initially assigned the structure of 3-methyl-5-(l,l,2-trinitroethyl)isoxazole [588], However, it was subsequently established that this compound was 5-methyl-4-nitro-3-(l,l-dinitroethyl)isoxazole [589], As mentioned earlier, the antibiotic azomycin (2-nitroimidazole) and some of its derivatives can be obtained by microbiological synthesis [331, 450, 590, 591],... 

The structure of nitroimidazoles has been studied more thoroughly and can be explained by wide application of these compounds, especially in medicine. In Table 3.3 some structural characteristics (X-ray and neutron study) for the imidazole and 2-nitroimidazole derivatives are given. 

It is interesting to note that the bond lengths C-S in two structurally related compounds l-(mesityl-2-sulfonyl)-3-nitro-l,2,4-triazole [120] and l-(mesitylsulfonyl)-4-nitroimidazole [121] are similar (1.761 and 1.758 A), while the S-N bond in imidazole analog is significantly shorter (1.736 and 1.708 A). 

As with pyrazoles, the introduction of the nitro group into the imidazole ring position 4(5) leads to an approximately 30 ppm lowfield shift of the tpxo-carbon signal resonance (Tables 3.6 and 3.10) [24, 321-329], Thus, the chemical shift of the carbon atom bonded to the N02 group (C-ipso) is 149.2 ppm, whereas that of neighboring carbon (C-5) is 119.8 ppm. In 1-substituted 4-nitroimidazoles (Table 3.11) the shifts of the same carbons are 146 1 and 122 2 ppm, while in 1-substituted 5-nitroimida-zoles they are 138 1 and 132 1 ppm, respectively (Table 3.12). All this may be indicative of the possible existence of 4(5)-nitroimidazole as a 4-nitro tautomer. Moreover, another support for the structure may be provided by comparison of the proton spin-spin coupling constants - J, 2J and 1/ Cl I-111) [321, 322, 330],... 

The hyperfine-shifted proton resonance of metmyoglobin and methemoglobin complexes with imidazoles, in particular, 4-nitroimidazole, was studied in order to obtain an insight into the structural features of the iron-bound imidazole [352], The structure of l-(l,3-dihydroxy-2-propyl)-4-nitroimidazoles, so called acyclic nucleosides, has been established by II and 13C NMR [327],... 

NMR spectroscopy is widely accepted to prove the structure of diverse bioactive nitroimidazoles [282, 316, 332, 346, 373, 452-479],... 

Similarly, in nitropyrazoles the C-nitro group vas and vs stretching frequencies are found in a range of 1510-1586 and 1320-1408 cm 1 [73, 297, 328, 362-364, 428, 465, 1031-1041], whereas the absorption maxima of nitroimidazole anions are displaced to the low-frequency region -1120-1200 and 1108-950 cm1, respectively [1033], The authors [1033] have established that the nitroimidazole sodium and potassium salts have a structure, with the negative charge mainly located on the nitro group (Scheme 3.45) ... 

Infrared spectroscopy is widely used for the structural determination of tautomers, isomers conformers of various nitroimidazoles [42, 1043], Vibration spectra of different 1-alkyl [362]-, l-(trialkylsilylalkyl)-2-methyl-4-nitroimidazoles [363], allylated 4-nitroimidazoles [364], dinitroimidazoles [428] have been studied. The vibration frequencies of some medicinal compounds on the base nitroimidazoles, for example, diasteriomeric nido-carboranyl misonidazole congeners [389], antiviral agents [452], and adrenergic-receptor agonists [454] are analyzed. In the literature the number of publications devoted to vibration spectra is rather limited and, as a rule, the absorption band frequencies of nitroimidazoles are considered in synthetic works concerned with structure identification such as, for example, [354, 429, 461-464,468-471, 1044-1047],... 

Methyl-substituted nitrodiazoles (nitropyrazoles and nitroimidazoles) in which the substituents occupy adjacent positions in the cycle are subject to several ortho effects [1283, 1284], The latest are useful in structure determination and isomer recognition of compounds. These effects are attributed to interaction of the substituents only. As a result, in some cases loss of OH and H20 [1283], and CHO and CH20 [1284] is observed. The way by which loss of H20 in 3(5)-nitro-4-meth-ylpyrazole occurs is shown in Scheme 3.52 [1283] ... 

The iV-methyl group is the source of one of the eliminated hydrogen. The subsequent loss of water by 1,2-elimination gives rise to the formation of the nitrile structure. Mass spectra of mono-, di-, and trideuterated nitroimidazoles were investigated in order to prove the fragmentation mechanism [1307],... 

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