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Jacques Vervoort - One of the best experts on this subject based on the ideXlab platform.
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regioselectivity of cytochrome p 450 catalyzed hydroxylation of Fluorobenzenes predicted by calculated frontier orbital substrate characteristics
Biochemistry, 1993Co-Authors: Ivonne M.c.m. Rietjens, Ans E.m.f. Soffers, Cees Veeger, Jacques VervoortAbstract:In the present study, a hypothesis is presented for the prediction of the regioselectivity of cytochrome P-450 catalyzed hydroxylation of Fluorobenzenes. The regioselectivity of the in vivo hydroxylation of Fluorobenzene, 1,2-diFluorobenzene, 1,3-diFluorobenzene, 1,2,3-triFluorobenzene, and 1,2,4-triFluorobenzene could be predicted within 6% accuracy on the basis of the substrate's frontier orbital characteristics for electrophilic attack. The in vivo regioselectivity of the hydroxylation of Fluorobenzene was not significantly influenced by changes in the cytochrome P-450 enzyme pattern. This implies that the regioselectivity is not predominantly determined by the juxtaposition of the relatively small substrates in the active sites of the cytochrome P-450s catalyzing the reaction
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regioselectivity of cytochrome p 450 catalyzed hydroxylation of Fluorobenzenes predicted by calculated frontier orbital substrate characteristics
Biochemistry, 1993Co-Authors: Ivonne M.c.m. Rietjens, Ans E.m.f. Soffers, Cees Veeger, Jacques VervoortAbstract:In the present study, a hypothesis is presented for the prediction of the regioselectivity of cytochrome P-450 catalyzed hydroxylation of Fluorobenzenes. The regioselectivity of the in vivo hydroxylation of Fluorobenzene, 1,2-diFluorobenzene, 1,3-diFluorobenzene, 1,2,3-triluorobenzene, and 1,2,4-triflurobenzene could be predicted within 6% accuracy on the basis of the substrate's frontier orbital characteristics for electrophilic attack. The in vivo regioselectivity of the hydroxylation of Fluorobenzene was not significantly influenced by changes in the cytochrome P-450 enzyme pattern. This implies that the regioselectivity is not predominantly determined by the juxtaposition of the relatively small substrates in the active sites of the cytochrome P-450s catalyzing the reaction. Additional in vitro experiments using 1,2-diFluorobenzene as the model substrate demonstrated that minor factors influencing the regioselectivity and possibly responsible for the 6% deviation from the calculated values in in vivo experiments might be (i) the influence of biotransformation routes occurring in vivo but not of importance in in vitro microsomal incubations and (ii) a small variation due to influences of the contribution of various cytochrome P-450 enzymes. On the basis of the results obtained, it is concluded that the aromatic hydroxylation of Fluorobenzenes proceeds through an initial electrophilic attack of (FeO)3+ on the aromatic substrate, and not through initial electron abstraction followed by attack of the (FeO)2+ species on the substrate radical cation. The fact that the regioselectivity observed could be predicted and/or explained by the site of initial (FeO)3+ attack also argues against epoxides as important intermediates in the formation of phenol metabolites from Fluorobenzenes.
Stephen G Kukolich - One of the best experts on this subject based on the ideXlab platform.
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measurements of deuterium quadrupole coupling in propiolic acid and Fluorobenzenes using pulsed beam fourier transform microwave spectrometers
Journal of Chemical Physics, 2015Co-Authors: M Sun, Bryan A Sargus, Spencer J Carey, Stephen G KukolichAbstract:The pure rotational spectra of deuterated propiolic acids (HCCCOOD and DCCCOOH), 1-Fluorobenzene (4-d1), and 1,2-diFluorobenzene (4-d1) in their ground states have been measured using two Fourier transform microwave (FTMW) spectrometers at the University of Arizona. For 1-Fluorobenzene (4-d1), nine hyperfine lines of three different ΔJ = 0 and 1 transitions were measured to check the synthesis method and resolution. For 1,2-diFluorobenzene (4-d1), we obtained 44 hyperfine transitions from 1 to 12 GHz, including 14 different ΔJ = 0, 1 transitions. Deuterium quadrupole coupling constants along the three principal inertia axes were well determined. For deuterated propiolic acids, 37 hyperfine lines of Pro-OD and 59 hyperfine lines of Pro-CD, covering 11 and 12 different ΔJ = − 1, 0, 1 transitions, respectively, were obtained from 5 to 16 GHz. Deuterium quadrupole coupling constants along the three inertia axes were well resolved for Pro-OD. For Pro-CD, only eQqaa was determined due to the near coincidence of the CD bond and the least principal inertia axis. Some measurements were made using a newer FTMW spectrometer employing multiple free induction decays as well as background subtraction. For 1-Fluorobenzene (4-d1) and 1,2-diFluorobenzene (4-d1), a very large-cavity (1.2 m mirror dia.) spectrometer yielded very high resolution (2 kHz) spectra.
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measurements of deuterium quadrupole coupling in propiolic acid and Fluorobenzenes using pulsed beam fourier transform microwave spectrometers
Journal of Chemical Physics, 2015Co-Authors: Bryan A Sargus, Spencer J Carey, Stephen G KukolichAbstract:The pure rotational spectra of deuterated propiolic acids (HCCCOOD and DCCCOOH), 1-Fluorobenzene (4-d1), and 1,2-diFluorobenzene (4-d1) in their ground states have been measured using two Fourier transform microwave (FTMW) spectrometers at the University of Arizona. For 1-Fluorobenzene (4-d1), nine hyperfine lines of three different ΔJ = 0 and 1 transitions were measured to check the synthesis method and resolution. For 1,2-diFluorobenzene (4-d1), we obtained 44 hyperfine transitions from 1 to 12 GHz, including 14 different ΔJ = 0, 1 transitions. Deuterium quadrupole coupling constants along the three principal inertia axes were well determined. For deuterated propiolic acids, 37 hyperfine lines of Pro-OD and 59 hyperfine lines of Pro-CD, covering 11 and 12 different ΔJ = − 1, 0, 1 transitions, respectively, were obtained from 5 to 16 GHz. Deuterium quadrupole coupling constants along the three inertia axes were well resolved for Pro-OD. For Pro-CD, only eQqaa was determined due to the near coincidence of...
Gautam R Desiraju - One of the best experts on this subject based on the ideXlab platform.
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long range synthon aufbau modules lsam in crystal structures systematic changes in c6h6 nfn 0 n 6 Fluorobenzenes
CrystEngComm, 2010Co-Authors: Parthasarathy Ganguly, Gautam R DesirajuAbstract:We discuss the assembly of a three-dimensional molecular crystal in terms of short-range supramolecular synthons that spontaneously organize themselves according to Aufbau principles into long-range geometries characteristic of the molecules themselves. For this purpose we have examined the systematic changes in the known crystal structures of a family of Fluorobenzenes, C6H6-nFn, where 0 2D -> 3D assembly seem to be more influenced by the packing of LSAMs than by any other factor. In these final stages, there may not be so much influence exerted by the stronger short-range synthons. We discuss the evolution of these Fluorobenzene crystal structures in terms of putative LSAMs and the purely geometric relationships between the n and (6 - n) compounds that can thus be expected. Such particle-hole pairs show structural similarities. Our discussion is quantified by the interpretation of intermolecular distances in terms of atomic sizes and with qualitative predictions of magnetic model systems.
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c h f interactions in the crystal structures of some Fluorobenzenes
Journal of the American Chemical Society, 1998Co-Authors: Venkat R Thalladi, Hanschristoph Weiss, Dieter Blaser, Roland Boese, Ashwini Nangia, Gautam R DesirajuAbstract:The existence and nature of C−H···F−C interactions in crystalline Fluorobenzenes 1−3 and 7−10 are discussed. These compounds were chosen because they contain only C, H, and F atoms; this is necessary in the evaluation of the weak acceptor capabilities of the C−F group. All of these compounds are liquids at room temperature, and single crystals for X-ray diffraction were grown in situ. The analysis of the C−H···F interactions that are found in all of these crystal structures takes the form of comparisons with related C−H···O/C−H···N analogues. Fluorobenzene, 1, bears a close relationship to pyridinium fluoride, pyridine 1-oxide, and benzonitrile at the level of individual interactions, showing that the character of the structure-determining intermolecular interactions in these four crystal structures are the same. Similarly, 1,4-diFluorobenzene, 3, and 1,4-benzoquinone are related, the C−H···F interactions in the former playing the same structural role as the C−H···O interactions in the latter. A compariso...
Ivonne M.c.m. Rietjens - One of the best experts on this subject based on the ideXlab platform.
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regioselectivity of cytochrome p 450 catalyzed hydroxylation of Fluorobenzenes predicted by calculated frontier orbital substrate characteristics
Biochemistry, 1993Co-Authors: Ivonne M.c.m. Rietjens, Ans E.m.f. Soffers, Cees Veeger, Jacques VervoortAbstract:In the present study, a hypothesis is presented for the prediction of the regioselectivity of cytochrome P-450 catalyzed hydroxylation of Fluorobenzenes. The regioselectivity of the in vivo hydroxylation of Fluorobenzene, 1,2-diFluorobenzene, 1,3-diFluorobenzene, 1,2,3-triFluorobenzene, and 1,2,4-triFluorobenzene could be predicted within 6% accuracy on the basis of the substrate's frontier orbital characteristics for electrophilic attack. The in vivo regioselectivity of the hydroxylation of Fluorobenzene was not significantly influenced by changes in the cytochrome P-450 enzyme pattern. This implies that the regioselectivity is not predominantly determined by the juxtaposition of the relatively small substrates in the active sites of the cytochrome P-450s catalyzing the reaction
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regioselectivity of cytochrome p 450 catalyzed hydroxylation of Fluorobenzenes predicted by calculated frontier orbital substrate characteristics
Biochemistry, 1993Co-Authors: Ivonne M.c.m. Rietjens, Ans E.m.f. Soffers, Cees Veeger, Jacques VervoortAbstract:In the present study, a hypothesis is presented for the prediction of the regioselectivity of cytochrome P-450 catalyzed hydroxylation of Fluorobenzenes. The regioselectivity of the in vivo hydroxylation of Fluorobenzene, 1,2-diFluorobenzene, 1,3-diFluorobenzene, 1,2,3-triluorobenzene, and 1,2,4-triflurobenzene could be predicted within 6% accuracy on the basis of the substrate's frontier orbital characteristics for electrophilic attack. The in vivo regioselectivity of the hydroxylation of Fluorobenzene was not significantly influenced by changes in the cytochrome P-450 enzyme pattern. This implies that the regioselectivity is not predominantly determined by the juxtaposition of the relatively small substrates in the active sites of the cytochrome P-450s catalyzing the reaction. Additional in vitro experiments using 1,2-diFluorobenzene as the model substrate demonstrated that minor factors influencing the regioselectivity and possibly responsible for the 6% deviation from the calculated values in in vivo experiments might be (i) the influence of biotransformation routes occurring in vivo but not of importance in in vitro microsomal incubations and (ii) a small variation due to influences of the contribution of various cytochrome P-450 enzymes. On the basis of the results obtained, it is concluded that the aromatic hydroxylation of Fluorobenzenes proceeds through an initial electrophilic attack of (FeO)3+ on the aromatic substrate, and not through initial electron abstraction followed by attack of the (FeO)2+ species on the substrate radical cation. The fact that the regioselectivity observed could be predicted and/or explained by the site of initial (FeO)3+ attack also argues against epoxides as important intermediates in the formation of phenol metabolites from Fluorobenzenes.
Adrian B Chaplin - One of the best experts on this subject based on the ideXlab platform.
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isolation and structural characterisation of rhodium iii η2 fluoroarene complexes experimental verification of predicted regioselectivity
Dalton Transactions, 2020Co-Authors: Matthew R Gyton, Amy E Kynman, Angello Gallo, Jozef R Lewandowski, Baptiste Leforestier, Adrian B ChaplinAbstract:The isolation and solid-state characterisation of complexes featuring partially coordinated benzene, Fluorobenzene and all three isomers of diFluorobenzene are described. Supported by a DFT analysis, this well-defined homologous series demonstrates the preference for η2-coordination of fluoroarenes via the HCCH sites adjacent to a fluorine substituent.