4- and 5-nitroimidazoles: 13C NMR assignment of structure

McKillop, Alexander; Wright, Derek E.; Podmore, Michael L.; Chambers, Robert K.

doi:10.1016/s0040-4020(01)88621-x

Cited by 31 publications

(16 citation statements)

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“…As expected, all the nitroimidazoles show a single peak each for N-1 and N-3, around 220 ppm and 120 ppm, respectively, in good agreement with other experimental results for similar compounds. 46,47 The υ 15 N value for N-3 is almost invariant along the series, whereas a slight variation (up to ca 7 ppm) is found for N-1, which bears the different substituents, R1. Interestingly, the chemical shift of this nitrogen atom appears to be more sensitive to the substituent R2 at the adjacent C atom than to the directly attached R (compare, e.g., N1 entries for 3 and 4 in Table 2).…”

Section: Experimental Datamentioning

confidence: 97%

Probing NMR parameters, structure and dynamics of 5-nitroimidazole derivatives. Density functional study of prototypical radiosensitizers

Ramalho

Bühl

2004

Magn. Reson. Chem.

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The 15N chemical shifts of metronidazole (1), secnidazole (2), nimorazole (3) and tinidazole (4), radiosensitizers based on the 5-nitroimidazole motif, are reported. A detailed computational study of 1 is presented, calling special attention to the performance of various theoretical methods in reproducing the 13C and 15N data observed in solution. The most sophisticated approach involves density functional-based Car-Parrinello molecular dynamics simulations (CPMD) of 1 in aqueous solution (BP86 level) and averaging chemical shifts over snapshots from the trajectory. In the NMR calculations for these snapshots (performed at the B3LYP level), a small number of discrete water molecules are retained, and the remaining bulk solution effects are included via a polarizable continuum model (PCM). A similarly good accord with experiment is obtained from much less involved, static geometry optimization and NMR computation of pristine 1 employing a PCM approach. Solvent effects on delta(15N), which are of the order of up to 20 ppm, are not due to changes in geometric parameters upon solvation, but arise from the direct response of the electronic wavefunction to the presence of the solvent, which can be represented by discrete molecules and/or the dielectric bulk.

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Section: Experimental Datamentioning

confidence: 97%

Probing NMR parameters, structure and dynamics of 5-nitroimidazole derivatives. Density functional study of prototypical radiosensitizers

Ramalho

Bühl

2004

Magn. Reson. Chem.

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“…for free 4-nitroimidazole in this solvent (32)(33)(34), indicating that the ligands had been displaced from the coordination sphere.…”

Section: Infrared Spectroscopymentioning

confidence: 98%

“…Since the solid (9) contains the tautomeric form found to be highly dominant in solution (lo), the assignments proposed for solution spectra are used directly (32)(33)(34). In [Ag(N021mH)2]N03, coordination to the N3 lone pair of a formally neutral ligand induces relatively small shifts of 3.1 ppm downfield on C 2 and 2.5 ppm upfield on C4, whereas C5 is not displaced.…”

Section: Infrared Spectroscopymentioning

confidence: 99%

Preparation and structure of silver complexes with 4-nitroimidazole

Ségalas¹,

Beauchamp²

1992

Can. J. Chem.

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ISABELLE SEGALAS and ANDRE L. BEAUCHAMP. Can. J. Chem. 70, 943 (1992). The reaction of 4-nitroimidazole (NOJmH) with AgN0, and AgBF, in neutral or weakly acidic aqueous media yielded the insoluble [Ag(N021m)] compound, whose infrared and "C NMR spectra are consistent with a polymeric chain of deprotonated ligands bridging silver atoms via the endocyclic nitrogen atoms. In strongly acidic solution, [Ag(N021mH),]X salts (X = NO,, BF,) were obtained and their crystal structures were determined. [Ag(N021mH)2]N0,: monoclinic, P2/n, a = 14.214(1), b = 12.571(2), c = 14.222(1) A, P = 111.38(7)", Z = 8, R = 0.021, 3443 observed reflections; [Ag(N021mH)2]BF,: monoclinic, P 2 , / c , n = 9.543(4), b = 6.478(2), c = 20.869(9) A, P = 90.84(3)", Z = 4, R = 0.027, 1646 observed reflections. In both compounds, the two-coordinated metal forms roughly collinear bonds to two neutral ligands via the endocyclic nitrogen atom adjacent to the nitro group. One oxygen of each nitro group makes a secondary Ag-0 bond near the equatorial plane. 'The anions are hydrogen bonded to the ligand N-H groups and do not directly interact with the metal. Solution 'H and "C NMR spectra show that the cationic complexes dissociate in DMSO. The infrared and CP-MAS "C NMR spectra are discussed in connection with the coordination patterns observed.Key words: silver, imidazole, crystal structure, infrared spectroscopy, nuclear magnetic resonance.

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“…13 (28). After co-evaporation with dry pyridine (2 x 15 mL), compound 5 (0.36 g, 1.2 mmol) was mixed with dry pyridine (20 mL) and DIPEA (0.5 mL, 40 mmol) under argon.…”

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confidence: 99%

Preparation of pyridine-stretched 2'-deoxyhypoxanthosine phosphoramidite

Clayton¹,

Davis

et al. 2017

Arkivoc

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Pyridine-stretched 2′-deoxyhypoxanthosine (strH) phosphoramidite was prepared in eight steps from Hoffer's sugar (2′-deoxy-3,5-di-O-(p-toluoyl)--D-erythro-pentofuranosyl chloride). Improved synthesis of the Hoffer sugar was achieved without need for distillation or chromatographic separation of intermediates, or use of gaseous HCl. Conditions were optimised to provide a key nitrile intermediate for the preparation of strH whereby the cesium salt of 4(5)-nitroimidazole was glycosylated using Hoffer's sugar. The nitrile intermediate was also used to prepare pyridine-stretched 2′-deoxyadenosine (strA) and pyridine-stretched 2′-deoxy-2,6-diaminonebulamine (strD). Preliminary studies indicate that strH forms a stronger, size-expanded base pair with adenine compared with the Watson-Crick thymine-adenine base pair.

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4- and 5-nitroimidazoles: 13C NMR assignment of structure

Cited by 31 publications

References 1 publication

Probing NMR parameters, structure and dynamics of 5-nitroimidazole derivatives. Density functional study of prototypical radiosensitizers

Probing NMR parameters, structure and dynamics of 5-nitroimidazole derivatives. Density functional study of prototypical radiosensitizers

Preparation and structure of silver complexes with 4-nitroimidazole

Preparation of pyridine-stretched 2'-deoxyhypoxanthosine phosphoramidite

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