Fluorine-19 Nuclear Magnetic Resonance Spectroscopy (1979–1981)

Wray, Victor

doi:10.1016/s0066-4103(08)60285-9

Cited by 33 publications

(9 citation statements)

References 646 publications

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“…Other than these 2-C 3 F 7 I resonances, three peak groups are observed: a nonet at À61.6 ppm, a triplet at À81.3 ppm and another triplet at À119.8 ppm. The assignments are confirmed by the assignments found in the literature [35,50] and the theoretical values in Table 1.…”

Section: Pure Compoundssupporting

confidence: 86%

“…S1 of the Supporting information shows the 19 F NMR spectrum of the pure 2-C 3 F 7 I sample (sample 13) recorded unlocked at 299 K. The reference peak of C 6 F 6 is set at À164.9 ppm and is marked with an asterisk. The assignments are taken from the literature [50]. The theoretical values in Table 1 are predicted as À92.8 ppm and À160.6 ppm, respectively.…”

Section: Pure Compoundsmentioning

confidence: 99%

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A 19F NMR study of C–I⋯π halogen bonding

et al. 2011

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Section: Pure Compoundssupporting

confidence: 86%

Section: Pure Compoundsmentioning

confidence: 99%

A 19F NMR study of C–I⋯π halogen bonding

et al. 2011

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“…(Fig. 2c, insert), the resonance at Ϫ201.0 ppm is assigned to 5-fluoromuconolactone, with a 2 J(5F,5H) of 47.4 Hz and a 3 J(5F,4H) of 25.2 Hz, being in line with what is generally observed for these types of coupling constants (3,45). From the 19 F NMR data of incubations with different ClcB2 concentrations, it was estimated that under the conditions employed, the relative rate of the ClcB2-mediated conversion of 2-fluoromuconate was about 2% of the rate with 2-chloromuconate.…”

Section: Resultssupporting

confidence: 83%

Conversion of 2-Fluoromuconate tocis-Dienelactone by Purified Enzymes ofRhodococcus opacus1cp

Solyanikova

Moiseeva

Boeren³

et al. 2003

Appl Environ Microbiol

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The present study describes the 19 F nuclear magnetic resonance analysis of the conversion of 3-halocatechols to lactones by purified chlorocatechol 1,2-dioxygenase (ClcA2), chloromuconate cycloisomerase (ClcB2), and chloromuconolactone dehalogenase (ClcF) from Rhodococcus opacus 1cp grown on 2-chlorophenol. The 3-halocatechol substrates were produced from the corresponding 2-halophenols by either phenol hydroxylase from Trichosporon cutaneum or 2-hydroxybiphenyl 3-mono-oxygenase from Pseudomonas azelaica.

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“…2b, inset). The size of these coupling constants is consistent with 3 J HF values generally observed in planar aromatic geometries and in fluorinated pyrones (5,22) but is not consistent with 3 J HF values previously reported for fluoromuconates, which vary between 10 and 40 ppm (2,22). This demonstrates that this resonance is not indicative of 2-hydroxy-4-fluoromuconate.…”

Section: Conversion Of Monofluorophenols By R Opacus 1cpsupporting

confidence: 65%

“…constants of 7.9 Hz are consistent with what would be expected for the two 3 J HF coupling constants in 2-pyrone-4-fluoro-6-carboxylate. The reported chemical shifts of 19 F for substituted 4-fluoropyrones are Ϫ85.7 and Ϫ86.5 ppm, while those of the C-4-fluoro substituent of 3,4-difluoropyrones are between Ϫ118 and Ϫ123 ppm (5,22). Taking into account a correction for the approximately Ϫ25-ppm change in chemical shift value upon introduction of an aromatic ortho-fluorine substituent (14,16), the chemical shift of 2-pyrone-4-fluoro-6-carboxylate is expected to be between Ϫ85 and Ϫ98 ppm, consistent with the observed value of Ϫ90.3 ppm.…”

Section: Conversion Of Monofluorophenols By R Opacus 1cpmentioning

confidence: 99%

Identification of Fluoropyrogallols as New Intermediates in Biotransformation of Monofluorophenols in Rhodococcus opacus 1cp

Finkelstein

Баскунов

Boersma

et al. 2000

Appl Environ Microbiol

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Halophenols and their derivatives are priority pollutants of mainly anthropogenic origin. Over several decades, these compounds have been widely used as building blocks in chemical and pharmaceutical syntheses and as herbicides and pesticides, and they have caused serious local contamination of the environment. Soil microorganisms have developed the capacity of utilizing halophenols for their growth by a diverse set of biodegradation pathways (8). Aerobic soil microorganisms generally degrade mono-and dihalophenols through the initial action of (chloro)phenol ortho-hydroxylases, leading to the formation of halocatechols (1,7,9,10,12). In the framework of a project devoted to the biodegradation of halophenols by gram-positive bacteria, we investigated the formation of hydroxylated intermediates formed upon the conversion of halophenols by various Rhodococcus species and previously demonstrated the formation of (halo)catechols as initial intermediates in the biodegradation pathways (3). However, identification of the subsequent biodegradation pathways of the chlorocatechols appeared hampered by the fact that unequivocal identification of the site of introduction of a third hydroxyl group is difficult because 1 H nuclear magnetic resonance (NMR) splitting patterns combined with 1 H chemical shift data of the protons present in these metabolites can be compatible with more than one substitution pattern (13). Therefore, in this paper, we have studied the possible formation of trihydroxyfluorobenzene metabolites from fluorophenols by whole cells of Rhodococcus opacus 1cp in detail. The fluorine substituent provides the possibility to detect and quantify the possible hydroxyfluorobenzene intermediates by 19 F NMR, allowing the identification of the exact substitution pattern. Using this technique we unambiguously demonstrate the formation of fluoropyrogallols (1,2,3-trihydroxyfluorobenzenes) as new intermediates in the biotransformation of monofluorophenols by R. opacus 1cp. MATERIALS AND METHODS Chemicals.Phenol was purchased from Merck (Darmstadt, Germany). 2-Fluorophenol, 3-fluorophenol, and 4-fluorophenol were purchased from Janssen Chimica (Beerse, Belgium). Fluorocatechols were prepared from the corresponding fluorophenols using purified phenol hydroxylase from Trichosporon cutaneum (14). Fluoromuconates were prepared and identified as described previously (2) by incubating the fluorocatechols with catechol 1,2-dioxygenase from Pseudomonas arvilla C-1.Growth of R. opacus 1cp. The strain R. opacus 1cp was isolated and maintained as described previously (6). The strain can grow on phenol as the sole source of carbon. For cultivation, a mineral synthetic medium containing, per liter, 1 g of NH 4 NO 3 , 1 g of K 2 HPO 4 , 1 g of KH 2 PO 4 , 0.2 g of MgSO 4 ⅐ 7H 2 O, 0.02 g of CaCl 2 , and 2 drops of a saturated solution of FeCl 3 (pH 7.2) was used. Phenol was used as the source of carbon and was initially added at a 200-mg/liter final concentration. R. opacus 1cp did not grow on either of the three monofluorophenols ...

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Fluorine-19 Nuclear Magnetic Resonance Spectroscopy (1979–1981)

Cited by 33 publications

References 646 publications

A 19F NMR study of C–I⋯π halogen bonding

A 19F NMR study of C–I⋯π halogen bonding

Conversion of 2-Fluoromuconate tocis-Dienelactone by Purified Enzymes ofRhodococcus opacus1cp

Identification of Fluoropyrogallols as New Intermediates in Biotransformation of Monofluorophenols in Rhodococcus opacus 1cp

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