Proton nuclear magnetic resonance study of the site of metal binding in tetracycline

Williamson, D. E.; Everett, Grover W.

doi:10.1021/ja00842a015

Cited by 63 publications

(26 citation statements)

References 5 publications

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“…[17][18][19][20][21][22][23] Two regions in Dox 1 H NMR spectrum are of special interest for the attribution of metal coordination sites: the D ring aromatics and the dimethylamino, C4, C4a, and C6 protons on ring A. These protons are not labile and their chemical shift, which is very sensitive to metal coordination, can be distinguished if the coordination occurs through O10 and O12 sites or through A ring sites.…”

Section: Resultsmentioning

confidence: 99%

Three new complexes of platinum(II) with doxycycline, oxytetracycline and chlortetracycline and their antimicrobial activity

Guerra

Silva

Azevedo

et al. 2006

J. Braz. Chem. Soc.

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Este artigo descreve a síntese e a caracterização de três novos complexos de platina(II) com a oxitetraciclina, doxiciclina e clortetraciclina por análise elementar, espectroscopias IV e RMN de II ions as a function of the pH were studied by 1 H NMR. All the investigated tetracyclines form 1:1 complexes with Pt II via the oxygen of the hydroxyl group and oxygen of the amide group at ring A. The minimal inhibitory concentrations (MIC) of the ligands and those of their Pt II compounds were determined in two sensitive strains (E. coli HB 101 and E. coli ATCC 25922) and in a resistant one (E. coli HB101/ pBR322). Platinum complex of doxycycline is twice as potent as the free antibiotic in the resistant strain. Octanol/water partition coefficients of the complexes were determined. Increasing lipophilicity enhances antimicrobial activity in the resistant strain.

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Section: Resultsmentioning

confidence: 99%

Three new complexes of platinum(II) with doxycycline, oxytetracycline and chlortetracycline and their antimicrobial activity

Guerra

Silva

Azevedo

et al. 2006

J. Braz. Chem. Soc.

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“…BF 3 ÁOEt 2 , HF/NaF, CsF, KF, nBu 4 NF (TBAF), 8,25,[93][94][95] etc., are the best choice of reagents for cleaving silyl ethers [96][97][98][99][100] under conditions that affect nearly no other functionalities. Of the known fluoride-based reagents, TBAF in tetrahydrofuran (THF) and KF have a selectivity in the desilylation of phenolic or diphenolic silyl ethers.…”

Section: Fluoride-based Reagentsmentioning

confidence: 99%

“…[1][2][3][4][5][6] For instance, several of the best known and widely used anthracycline and tetracycline antibiotics possess the hydroxyquinone structure, which is thought to be responsible for their biological activity. 7,8 Since the introduction of trimethylsilyl (TMS) ethers in the early 1970s for the protection of hydroxy groups, 9 the use of organosilicon reagents, as protective groups, has undergone substantial development. It is fair to say that, to date, in any relevant synthesis of reasonable complexity, the use of an organosilicon reagent of some kind is unavoidable.…”

Section: Introductionmentioning

confidence: 99%

“…18 Silyl derivatives of the wellknown bioactive hydroxyquinones 19,20 are also expected to be highly bioactive. 2,3,7,8,21 The silylation reactions of quinones with trialkylsilyl groups are of great importance for synthetic, analytical and biological purposes for the protection of the reactive quinonic moiety in a wide range of naturally occurring and biologically important macromolecules. The protection of the highly reactive hydroquinone function as a silyl ether, against destructive conditions, during multi-stage syntheses of several quinonoid compounds, followed by synthetic elaboration and oxidation, is an important synthetic strategy for the preparation of complex quinones.…”

Section: Introductionmentioning

confidence: 99%

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Silylation–desilylation of quinones and their derivatives

Bakola‐Christianopoulou

2001

Applied Organom Chemis

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The silylation of quinones and their substituted derivatives for the protection of the reactive quinonic moiety and/or reactive substituents (in particular hydroxyl groups) is discussed in view of the wide applicability of the reaction for synthetic, biological and analytical purposes. Furthermore, the most common and efficient methods for the subsequent desilylation of the silylated quinones and their derivatives to the parent quinones or to the corresponding hydroquinones are discussed.

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“…The properties of TCs-metal ion-chelates have been investigated by multiple techniques, such as UVeVis absorption spectroscopy and fluorescence spectroscopy , infrared (IR) spectroscopy (Zhang et al, 2012), circular dichroism spectroscopy (Jezowska-Bojczuk et al, 1993;Wessels et al, 1998), electronic analytical methods (Zhao et al, 2013), and nuclear magnetic resonance spectroscopy (Williamson and Everett, 1975). The binding sites and stoichiometry of the complexes were metal ion-and pH-dependent.…”

Section: Introductionmentioning

confidence: 99%

The effect of Cu2+ chelation on the direct photolysis of oxytetracycline: A study assisted by spectroscopy analysis and DFT calculation

Jin

Qiu

et al. 2016

Environmental Pollution

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Chelation Direct photolysis TD-DFT a b s t r a c tThe extensive usage of OTC and Cu 2þ in livestock and poultry industry caused high residues in natural environment. Co-contamination of OTC and Cu 2þ was a considerable environmental problem in surface waters. In this study, Cu 2þ mediated direct photolysis of OTC was studied. Cu 2þ chelating with OTC was found to greatly inhibit OTC photodegradation. To reveal the chelation mechanism of OTC-Cu complexes, multiple methods including UVeVis absorption spectra, Infrared (IR) spectra, mass spectroscopy, and density functional theoretical (DFT) modeling were performed. Four OTC-Cu complexes were proposed. Cu 2þ preferably bond to O 11 eO 12 site with the binding constants logK ¼ 8.19 and 7.86 for CuHLþ and CuL±, respectively. The second chelating site was suggested to be O2eO3 with the binding constants of logK ¼ 4.41 and 4.62 for Cu2HL3þ and Cu2L2þ, respectively. The suppressed quantum yield of OTC by Cu2þ chelation was accused for their intra-/inter-molecular electron transfer, by which the energy in activated states was distributed. The occurrence of electron transfer between BCD ring and A ring also from BCD ring to Cu was evidenced by the TD-DFT result only for the OTC-Cu complexes. Besides, the cyclic voltammetry measurement also suggested one OTC-Cu(II)/OTC-Cu(I) redox couple. These results suggested that the persistence of OTC in environmental surface waters will probably be underestimated for neglecting the chelating effect of Cu2þ. The photolysis quantum yield of OTC-Cu complexes, as well as the specific molar absorption constants, the equilibrium binding constants of Cu2þ with OTC could contribute to more accurate kinetic models of OTC.

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Proton nuclear magnetic resonance study of the site of metal binding in tetracycline

Cited by 63 publications

References 5 publications

Three new complexes of platinum(II) with doxycycline, oxytetracycline and chlortetracycline and their antimicrobial activity

Three new complexes of platinum(II) with doxycycline, oxytetracycline and chlortetracycline and their antimicrobial activity

Silylation–desilylation of quinones and their derivatives

The effect of Cu2+ chelation on the direct photolysis of oxytetracycline: A study assisted by spectroscopy analysis and DFT calculation

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