Journal of the American Chemical Society
Article
ethyl phenyl sulfide were purchased and used without further
purification. Reagents for kinetics were of AR or ARISTAR quality;
the water used as a solvent was distilled. Concentrated solutions of
NaOD in D2O were purchased and diluted with 99.8% D2O.
AUTHOR INFORMATION
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Corresponding Author
Reagents for Kinetic Measurements. The substituted benzene
cis-1,2-dihydrodiols studied kinetically in this work were prepared
earlier by bacterial oxidation of the corresponding substituted benzene
substrates by dioxygenase enzymes present in cultures of P. putida
UV4.42a−c The structures and spectra of most of the dihydrodiol
metabolites, including the unsubstituted benzene cis-dihydrodiol and
benzene cis-dihydrodiols with 3-substituents chloro, bromo, iodo,
phenyl, carbethoxy, trifluoromethyl, and methylsulfoxy were reported
previously.42 Proton NMR spectra are included in the Supporting
Information. Deuterated cis-1,2-dihydrodiols were prepared by similar
biotransformations of hexadeuterobenzene, pentadeutero bromoben-
zene, pentadeutero chlorobenzene and perdeuterated toluene. They
were identified from their Rf values on silica preparative layer
chromatography plates, which were identical to those of their
undeuterated analogues, and similarly identical reactant and product
UV spectra before and after hydroxide ion-catalyzed dehydration. The
perdeutero 3-cyanobenzene cis-dihydrodiol was prepared from the
corresponding 3-iodo-substituted cis-dihydrodiol by reaction with
tributyltin cyanide and Pd(Ph3P)4 for 4 h in THF solvent, as described
by Boyd et al.42a for the corresponding undeuterated compound.
Product Analyses. Products of the reactions of substituted
benzene cis-1,2-dihydrodiols in sodium hydroxide were analyzed by
NMR spectroscopy, HPLC, or GC−MS to identify and determine the
ratio of ortho- to meta-substituted phenols formed. The following
analysis for cis-1,2-dihydroxy-3-bromo-1,2-cyclohexa-3,5-diene is typ-
ical. The cis-dihydrodiol reactant (30 mg) in acetonitrile (5 mL) was
treated with a solution of 1.0 M sodium hydroxide for 15 h at 25 °C.
The pH of the reaction mixture was adjusted to 6−7 with saturated
aqueous sodium bicarbonate, and this was followed by extraction with
ethyl acetate and evaporation of the solvent under reduced pressure.
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
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This paper is dedicated to the memory of Rory More O’Ferrall,
our colleague, collaborator, and friend. This work was
supported by the Science Foundation Ireland (Grant 04/
IN3/B581). Financial support for D.E.B. from the EPSRC and
the University of Sheffield (U.K.) is also gratefully acknowl-
edged, as is a Royal Society Conference Travel Grant for P.W.F.
Support for S.G. was provided by the National Science
Foundation (CHE-0716147). Support for S.C.L.K. was
provided by the Swedish Research Council, Vetenskapradet
(Grant No. 2012-5026).
̊
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The H NMR spectrum was recorded, and the ratio of products was
determined by HPLC. Comparison of the HPLC peaks with those of
authentic samples of the isomeric products confirmed their identity
and allowed correction of the measured peak intensities for a small
difference in response factors (m-bromo/o-bromo = 0.9), to give 11%
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UV−vis spectra of reactants and products (Figures S1 and S2);
isotope effects (Table S1 and Figures S3−S5); product analyses
(Figure S7); measurements of ionization constants (Table S2);
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absorbances as a function of [HO−] for cyanobenzene 1,2-
dihydrodiol (Figure S6); plot of computed versus experimental
proton affinities for various anions (Figure S8); and NMR
spectra. This material is available free of charge via the Internet
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