- Inhibition of Urease, a Ni-Enzyme: The Reactivity of a Key Thiol With Mono- and Di-Substituted Catechols Elucidated by Kinetic, Structural, and Theoretical Studies
-
The inhibition of urease from Sporosarcina pasteurii (SPU) and Canavalia ensiformis (jack bean, JBU) by a class of six aromatic poly-hydroxylated molecules, namely mono- and dimethyl-substituted catechols, was investigated on the basis of the inhibitory efficiency of the catechol scaffold. The aim was to probe the key step of a mechanism proposed for the inhibition of SPU by catechol, namely the sulfanyl radical attack on the aromatic ring, as well as to obtain critical information on the effect of substituents of the catechol aromatic ring on the inhibition efficacy of its derivatives. The crystal structures of all six SPU-inhibitors complexes, determined at high resolution, as well as kinetic data obtained on JBU and theoretical studies of the reaction mechanism using quantum mechanical calculations, revealed the occurrence of an irreversible inactivation of urease by means of a radical-based autocatalytic multistep mechanism, and indicate that, among all tested catechols, the mono-substituted 3-methyl-catechol is the most efficient inhibitor for urease.
- Mazzei, Luca,Contaldo, Umberto,Musiani, Francesco,Cianci, Michele,Bagnolini, Greta,Roberti, Marinella,Ciurli, Stefano
-
supporting information
p. 6029 - 6035
(2021/02/09)
-
- 4-methylcatechol Derivatives and Uses Thereof
-
The invention relates to phenoxy derivatives with glycosidically bound sugar moieties, pharmaceutical compositions containing such compounds, uses of such compounds and compositions, and methods of making such compounds and pharmaceutical compositions.
- -
-
Paragraph 0094
(2016/12/22)
-
- Development of an iron(II)-catalyzed aerobic catechol cleavage and biomimetic synthesis of betanidin
-
An aerobic iron(II)-catalyzed cleavage of catechols was developed. This reaction allows for the preparation of 2-methoxy-2H-pyrans that can be employed as versatile building blocks for synthesis. The utility of this biomimetic oxidative cleavage is featured in the synthesis of betanidin, a natural colorant with antioxidant properties. Cut and paste: An aerobic iron(II)-catalyzed oxidative cleavage of catechol was developed. This reaction allows the preparation of 2H-pyrans that can be employed as versatile building blocks for synthesis. The utility of this biomimetic cleavage is featured in the synthesis of betanidin, the aglycone of red beets' principal colorant and itself a valuable antioxidant (see scheme).
- Guimond, Nicolas,Mayer, Peter,Trauner, Dirk
-
supporting information
p. 9519 - 9523
(2014/08/18)
-
- Layer-by-Layer coated tyrosinase: An efficient and selective synthesis of catechols
-
Agaricus bisporous tyrosinase was immobilized on commercial available epoxy-resin EupergitC250L and then coated by the Layer-by-Layer method (LbL). The two novel heterogeneous biocatalysts were characterized for their morphology, pH and storage stability, kinetic properties (Km, V max, Vmax/Km) and reusability. These biocatalysts were used for the efficient and selective synthesis of bioactive catechols under mild and environmental friendly experimental conditions. Ascorbic acid was added in the reaction medium to inhibit the formation of ortho-quinones, thus avoiding the known enzyme suicide inactivation process. Catechols were obtained mostly in quantitative yields and conversion of substrate. Tyrosinase immobilized on EupergitC250L and coated by the LbL method showed better catalytic activities, higher pH and storage stability, and reusability with respect to immobilized uncoated tyrosinase. Since chemical procedures to synthesize catechols are often expensive and with high environmental impact, the use of immobilized tyrosinase represents an efficient alternative for the preparation of this family of bioactive compounds.
- Guazzaroni, Melissa,Crestini, Claudia,Saladino, Raffaele
-
experimental part
p. 157 - 166
(2012/02/13)
-
- Synthesis of catechols from phenols via Pd-catalyzed silanol-directed C-H oxygenation
-
A silanol-directed, Pd-catalyzed C-H oxygenation of phenols into catechols is presented. This method is highly site selective and general, as it allows for oxygenation of not only electron-neutral but also electron-poor phenols. This method operates via a silanol-directed acetoxylation, followed by a subsequent acid-catalyzed cyclization reaction into a cyclic silicon-protected catechol. A routine desilylation of the silacyle with TBAF uncovers the catechol product.
- Huang, Chunhui,Ghavtadze, Nugzar,Chattopadhyay, Buddhadeb,Gevorgyan, Vladimir
-
supporting information; experimental part
p. 17630 - 17633
(2011/12/16)
-
- Nucleophilic deoxyfluorination of catechols
-
Nucleophilic deoxyfluorinaiton of one of the two hydroxyl groups of catechols has been developed via the Umpolung concept. This method was successively applied to naturally occurring catechols, such as catechins and dopamine, to produce novel fluorinated
- Nemoto, Hiroyuki,Nishiyama, Tsuyoshi,Akai, Shuji
-
supporting information; experimental part
p. 2714 - 2717
(2011/06/28)
-
- Highly substituted Schiff base macrocycles via hexasubstituted benzene: a convenient double Duff formylation of catechol derivatives
-
The synthesis of soluble, shape-persistent macrocycles is important for developing new materials. Double Duff formylation of 4,5-dialkylcatechol derivatives yields 3,6-diformyl-4,5-dialkylcatechols in moderate yields. These hexasubstituted aromatics are u
- Shopsowitz, Kevin E.,Edwards, David,Gallant, Amanda J.,MacLachlan, Mark J.
-
scheme or table
p. 8113 - 8119
(2009/12/09)
-
- An expedient one-pot entry to catecholestrogens and other catechol compounds via IBX-mediated phenolic oxygenation
-
A one-pot procedure for the preparation of catecholestrogens in over 90% yield is reported, involving oxygenation of 17β-estradiol or estrone with o-iodoxybenzoic acid (IBX) followed by reduction with methanolic NaBH 4. The procedure, which was extended to the o-hydroxylation of a number of representative phenols in good-to-high yields, expands significantly the scope of phenolic oxidation mediated by IBX.
- Pezzella, Alessandro,Lista, Liliana,Napolitano, Alessandra,D'Ischia, Marco
-
p. 3541 - 3544
(2007/10/03)
-
- Electronic and Steric Effects in the Dienone-Phenol Rearrangement of 2-Hydroxy- and 2-Alkoxycyclohexa-2,5-dien-1-ones
-
A series of 4,4,6-trisubstituted-2-hydroxy- and -2-alkoxycyclohexa-2,5-dien-1-ones (7 and 8) were prepared, where the substituent at C-6 was H, CH3, Ph, tert-butyl, or OEt.In the acid-catalyzed dienone-phenol rearrangement of 7 and 8, the C-4 substituent
- Frimer, Aryeh A.,Marks, Vered,Sprecher, Milon,Gilinsky-Sharon, Pessia
-
p. 1831 - 1834
(2007/10/02)
-
- 1,3-Halogen shift of 2-halogeno-4,5-dimethylphenols following oxidation with Fremy's salt
-
Oxidation of 2-bromo-6-deuterio-4,5-dimethylphenol with Fremy's salt, followed by in situ reduction, yielded mainly 3-bromo-4,5-dimethylpyrocatechol, which affords evidence for a 1,3-bromine shift during the oxidation.The same treatment of 2-chloro-4,5-di
- Jacobs, A. W. C. M.,Maat, L.
-
p. 183 - 185
(2007/10/02)
-
- Mechanism of the Oxidation of NADH by Quinones. Energetics of One-Electron and Hydride Routes
-
The kinetics of NADH oxidation by 7 o-benzoquinones and 14 p-benzoquinones were studied by using buffered aqueous solutions and UV/vis spectroscopy.For each quinone the rate law was first order in NADH and first order in quinone.The rate constants varied from 0.0745 to 9220 M-1s-1.Variation of the pH from 6 to 8 gave no change in rate.The use of 4-D and 4,4-D2NADH revealed kinetic isotope effects.The dideutero data gave kH/kD in the range 1.6-3.1 for p-quinones and 4.2 for 3,5-di-tert-butyl-o-quinone.When p-quinones were used, the log k was a linear function of Eo for the quinone/hydroquinone monoanion (Q/QH(1-)) couple with a slope of 16.9 V-1. o-Quinones reacted about 100 times more rapidly, but the same linear relationship with a slope of 16.4 V-1 was observed.Comparisons to data for one-electron-transfer reactions indicate that such mechanisms are not involved.A hydride-transfer mechanism accommodates all the data, and rate-limiting hydrogen atom transfer followed by electron transfer cannot be ruled out.
- Carlson, Brian W.,Miller, Larry L.
-
p. 479 - 485
(2007/10/02)
-
- Oxidation of (-)-2-bromo-3-hydroxy-N-methyl-6-oxomorphinan with Fremy's salt. An unprecedented 2,4-shift of the bromo substituent. (Chemistry of opium alkaloids, Part XIII)
-
(-)-3-hydroxy-N-methyl-6-oxomorphinan (6a) and its (-)-2-bromo derivative (6b) were converted into (-)-2,3-dihydroxy-N-methyl-6-oxomorphinan (8a) and its (-)-4-bromo derivative (8b), respectively, by oxidation with Fremy's salt to the ortho-quinones, foll
- Olieman, C.,Maat, L.,Beyerman, H. C.
-
p. 169 - 175
(2007/10/02)
-