N-methylcodeinium iodide—Crystal structure and spectroscopic elucidation

Seidel, Rüdiger W.; Bakalska, B.R.; Kolev, Tsonko; Vassilev, Dragomir; Mayer‐Figge, Heike; Spiteller, Michael; Sheldrick, William S.; Koleva, Bojidarka B.

doi:10.1016/j.saa.2009.01.017

Cited by 6 publications

(7 citation statements)

References 20 publications

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“…Values of Q clearly support the disposition Me‐22 axial and Me‐23 equatorial (Table ), and hence this is the assignment we used thereafter. This assignment is consistent with the one reported for MCI in acetonitrile …”

Section: Resultssupporting

confidence: 93%

“…). Conformer 1A corresponds to the crystallographic structure, has the lowest calculated energy, and therefore is the only one expected in solution, as the others are at least 7 kcal/mol higher in energy (Table ). Even though conformers 1B and 1C are not expected in solution on the basis of their computed energies, we also used them as a quality control in the fit of RDC as a way to illustrate the power of the methodology.…”

Section: Resultsmentioning

confidence: 99%

“…This assignment is consistent with the one reported for MCI in acetonitrile. [24] We also performed a multi-conformer analysis of the RDC data to address the possibility of the presence of a minor conformer in fastexchange equilibrium with 1A. It has been shown that, when conformational movements are of short amplitude, the singletensor approximation can be applied with confidence to fit RDC data to mixtures of conformers in fast exchange and to estimate their relative populations.…”

Section: Rdc Analysismentioning

confidence: 99%

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Influence of solvent and salt concentration on the alignment properties of acrylamide copolymer gels for the measurement of RDC

Trigo‐Mouriño

Navarro‐Vázquez

Sánchez-Pedregal

2012

Magnetic Reson in Chemistry

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The dependence of molecular alignment with solvent nature and salt concentration has been investigated for mechanically stretched polyacrylamide copolymer gels. Residual dipolar couplings (RDCs) were recorded for D(2)O, DMSO-d(6), and DMSO-d(6)/D(2)O solutions containing different proportions of the solvents and different sodium chloride concentrations. Alignment tensors were determined by fitting the experimental RDCs to the DFT-computed structure of N-methylcodeinium ion. Analysis of the tensors shows that the degree of alignment decreases with the proportion of DMSO-d(6) as well as with the concentration of sodium chloride, most likely due to enhanced ion-pair aggregation. Furthermore, rotation of the alignment tensor is observed when increasing the salt concentration.

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Section: Resultssupporting

confidence: 93%

Section: Resultsmentioning

confidence: 99%

Section: Rdc Analysismentioning

confidence: 99%

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Influence of solvent and salt concentration on the alignment properties of acrylamide copolymer gels for the measurement of RDC

Trigo‐Mouriño

Navarro‐Vázquez

Sánchez-Pedregal

2012

Magnetic Reson in Chemistry

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“…Figure 2 shows that the codeine features appear more sensitive to the solvent. In a recent FTIR study of N-methylcodeinium iodide, [30] no intramolecular O 15 H···O hydrogen bonding has been reported; the occurrence of an intermolecular OH···I À was suggested. Our results in C 2 Cl 4 solution show that the hydroxyl absorption of codeine is very similar to the one observed for galanthamine, the n(OH) vibration being located at 3570 cm À1 (Figure 2b).…”

Section: Resultsmentioning

confidence: 98%

“…The structural features of codeine obtained in the present work, in solution and in the gas phase agree well with those reported in the crystalline state. Indeed, neutral codeine structures [35,36] unambiguously show an O 15 H···O 4 intramolecular interaction (d H···O = 2.140 and 2.147 , respectively) as well as in an N-methylcodeinium iodide structure [30] despite the O 15 H···I À intermolecular interaction argued by the authors. A trans orientation of the methoxy substituent is found in both neutral codeine structures, whereas it adopts a gauche orientation in the N-methylcodeinium iodide structure, with a clear C 14 H···O 4 intramolecular interaction.…”

mentioning

confidence: 84%

Structural Features and Hydrogen‐Bond Properties of Galanthamine and Codeine: An Experimental and Theoretical Study

Atkinson

Baguet

Galland

et al. 2011

Chemistry A European J

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Structural features of galanthamine and codeine, two allosteric potentiating ligands of nicotinic acetylcholine receptors (nAChRs), have been investigated through experimental studies in solution by FTIR and NMR spectroscopy and by quantum chemical calculations in the isolated state. The infrared spectra accumulated in solvents of various polarities show that the intramolecular OH···O hydrogen bond in galanthamine is stronger than the corresponding interaction in codeine. Molecular electrostatic potential calculations allow rationalisation of the experimental trends. NOE measurements on the two ligands in the same solvent range show significant differences. In apolar solvents, the NMR spectroscopic data indicate the occurrence of CH···O hydrogen-bond interactions, whereas in the more polar solvents, a trans orientation of the methoxy group with respect to the furanyl oxygen atom is favoured. A natural bond orbital (NBO) analysis provides evidence that these stabilising interactions originate in the hyperconjugation between the lone pairs of the furanyl oxygen atoms, n(O), and the methoxy antibonding σ*(C-H) orbitals within the two molecules. Despite the strong structural similarities between the two allosteric modulators, FTIR equilibrium constants measurements of hydrogen-bond complexation combined with quantum chemistry calculations point out the significant increase of hydrogen-bond accepting strength of galanthamine relative to codeine. This increase is mainly assignable to the stronger hydrogen-bond basicity of the hydroxyl group, and to a lesser extent to the higher hydrogen-bond accepting strength of the amino nitrogen of galanthamine in comparison with the corresponding groups of codeine. An analysis of the interactions that occur between the two ligands and acetylcholine esterase (AChE) suggests significant differences with Trp84, a key component of the AChE catalytic active site. In contrast, both ligands appear to interact similarly with acetylcholine binding protein (AChBP).

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Disodium cromoglycate: exploiting its properties as a NMR weak-aligning medium for small organic molecules

2014

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Chromonic phases are a family of lyotropic liquid crystals (LC) formed by ionic aromatic mesogens such as disodium cromoglycate (cromolyn), sunset yellow and others. It is well known that chromonic phases are oriented in the presence of external magnetic fields, leading to the observation of anisotropic NMR observables such as quadrupolar splittings or residual dipolar couplings. Despite the fact that the cromolyn nematic LC phase (N) presents important advantages like great homogeneity, small line broadening, and easy sample preparation, it has been scarcely used as a water-compatible NMR orienting medium, in part due to a too strong induced degree of alignment on the guest molecules. However, the use of cromolyn-brine mixtures led to the optimum degree of alignment allowing to record (1)H-(13)C dipolar couplings with good accuracy.

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N-methylcodeinium iodide—Crystal structure and spectroscopic elucidation

Cited by 6 publications

References 20 publications

Influence of solvent and salt concentration on the alignment properties of acrylamide copolymer gels for the measurement of RDC

Influence of solvent and salt concentration on the alignment properties of acrylamide copolymer gels for the measurement of RDC

Structural Features and Hydrogen‐Bond Properties of Galanthamine and Codeine: An Experimental and Theoretical Study

Disodium cromoglycate: exploiting its properties as a NMR weak-aligning medium for small organic molecules

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