Structure cristalline de la rifampicine C43N4O12H58.5H2O

Gadret, M.; Goursolle, M.; Léger, J. M.; Colleter, J. C.

doi:10.1107/s0567740875005407

Cited by 31 publications

(21 citation statements)

References 2 publications

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“…1), which identifies the imine nitrogen as the most likely species able to bind directly to the metal surface. Furthermore, there are no significant stereochemical impediments 14 to an approximately end-on binding of the imine group to the Ag surface, facilitating intensification of the (C N) mode in accordance with the surface selection rules. The enhancement of strong and medium intensity in-plane ring stretching modes at 1581, 1522, 1391 and 1355 cm 1 , slightly shifted compared with their RR wavenumbers, indicates that the chromophore assumes a vertical orientation with respect to the Ag surface.…”

Section: Mechanism Of Adsorption -Rifampicinmentioning

confidence: 95%

“…Moreover, the X-ray structures of rifamycin SV and rifampicin reveal that although there are minor differences associated with the conformation of the ansa chain that connects the two ends of the chromophore, there is good correspondence between the bond lengths of their chromophore atoms. 13,14 In fact, there are several close structural similarities of particular importance for the following RR and SERRS spectral analysis. The C1-O, C4-O and C8-O bond distances (1.37, 1.37 and 1.27Å, respectively) are, within experimental error, the same for rifamycin SV and rifampicin.…”

Section: Resonance Raman Spectroscopymentioning

confidence: 99%

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Surface‐enhanced resonance Raman spectroscopy of rifamycins on silver nanoparticles: insight into their adsorption mechanisms

Howes

Scatragli

Marzocchi

et al. 2006

J Raman Spectroscopy

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Three widely used antibiotics from the rifamycin family, rifamycin SV sodium salt, rifampicin and rifaximin, have been characterized by resonance Raman (RR) and surface-enhanced resonance Raman spectroscopy (SERRS). SERRS spectra were recorded using aqueous silver colloidal dispersions prepared with two reducing agents, sodium borohydride and hydroxylamine hydrochloride, for a range of pH values to identify the SERRS-active substrate surface most suitable for each of the three antibiotics. Rifampicin was found to give intense SERRS signals only for the borohydride-reduced colloid and only at pH < 7.7, whereas the hydroxylamine HCl-reduced colloid was the best substrate for rifaximin, giving considerably more intense SERRS spectra than the borohydride colloid. SERRS spectra of rifaximin were observed only at pH < 7.0. It is proposed that the marked pH dependence of the SERRS enhancement results from a transition from an anionic to a neutral zwitterionic state. SERRS spectra of rifamycin SV were not observed for any experimental conditions. The antibiotics display remarkably contrasting SERRS behaviour, reflecting differences in the nature of the substituent groups on the chromophore ring. A vibrational assignment of the RR spectra and detailed comparison between the RR and SERRS data have given insight into the mechanism of adsorption of the antibiotics onto the Ag surface. Rifampicin and rifaximin adsorb adopting an approximately similar vertical orientation of the chromophore ring with respect to the surface; however, rifampicin adsorbs by direct chemical interaction with the Ag whereas rifaximin does not form a direct bond with the Ag surface.

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Section: Mechanism Of Adsorption -Rifampicinmentioning

confidence: 95%

Section: Resonance Raman Spectroscopymentioning

confidence: 99%

Surface‐enhanced resonance Raman spectroscopy of rifamycins on silver nanoparticles: insight into their adsorption mechanisms

Howes

Scatragli

Marzocchi

et al. 2006

J Raman Spectroscopy

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“…Conformation/activity studies have been carried out on rifamycins B, Y (Brufani, Cerrini, Fedeli & Vaciago, 1974), rifampicin (Gadret, Goursolle, Leger & Colleter, 1975) and tolypomycinone (Brufani, Cellai, Cerrini, Fedeli & Vaciago, 1978). To investigate further the relationship between the conformation of the ansa chain and the activity or inactivity of the ansamycins, X-ray studies were carried out on the iminomethyl ether derivative of rifamycin S (Fig.…”

Section: Introductionmentioning

confidence: 99%

Structural investigations of mode of action of drugs. III. Structure of rifamycin S iminomethyl ether

Arora¹

1981

Acta Crystallogr Sect B

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A structural study of rifamycin S iminomethyl ether (C38H47NO12) has been carried out by X-ray diffraction. The needle-shaped crystals belong to orthorhombic space group P212121. The unit-cell dimensions are a = 14.059 (3), b = 21.420 (5) and c = 26.961 (5) A. There are two molecules per asymmetric unit and eight molecules in the cell. The structure, with 102 nonhydrogen atoms in the asymmetric unit, was solved by repeated use of direct methods via tangent extension and refined by least-squares techniques to a final weighted residual of 0.109 for 4351 independent reflections. Attempts to locate H atoms were partially successful. The introduction of an extra double bond N=C(15) had a pronounced effect on the conformation of the ansa chain. The C(16)-C(17) and C(18)-C(19) double bonds are cis and trans respectively. The C(21)-O(10) and C(23)-O(9) bonds point toward the naphthoquinone ring rather than being parallel to it. A similar situation is observed in tolypomycinone and this seems to be the reason for the inactivity of both these compounds. There are four intramolecular and two intermolecular hydrogen bonds.

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“…This behaviour is consistent with the crystal structure which shows a nearly parallel alignment of the long chromophore axis to the c crystal axis. 12 The solid RIFSVNa excitation profiles cannot be interpreted in terms of a simple vibrational structure of a single electronic state. In fact, the broadness of the absorption band and the complex structure of the excitation profiles could be due to the crystal splitting of the electronic transition moment into two or three components of comparable intensity.…”

Section: Visible Spectra and Raman Excitation Profilesmentioning

confidence: 99%

Resonance Raman spectra and excitation profiles of some rifamycins

Angeloni

Marzocchi

Smulevich

1984

J Raman Spectroscopy

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The resonance Raman Spectra of rifamycin SV, its sodium salt and rifampicin have been investigated under various physical conditions. The excitation profiles of the strongest Raman bands have been measured using an Ar+ laser for excitation. The proposed vibrational assignment indicates that the group is the main portion of the chromophore for both rifamycin SV Na salt and rifampicin molecules. Excitation profile studies of the 6(C-O-) and v(C-OH) vibrations indicate the presence of a single electronic transition in the visible region.In addition these two modes derive their intensities from 0-1 vibromic transitions whereas no evidence for the contribution due to the 0-0 term is found. This is explained in terms of coupling with the other totally symmetric modes and broadening due to phonowlectron interactions.

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Structure cristalline de la rifampicine C43N4O12H58.5H2O

Cited by 31 publications

References 2 publications

Surface‐enhanced resonance Raman spectroscopy of rifamycins on silver nanoparticles: insight into their adsorption mechanisms

Surface‐enhanced resonance Raman spectroscopy of rifamycins on silver nanoparticles: insight into their adsorption mechanisms

Structural investigations of mode of action of drugs. III. Structure of rifamycin S iminomethyl ether

Resonance Raman spectra and excitation profiles of some rifamycins

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