24289-60-9Relevant articles and documents
Effective Oxygenation of 3,5-Di-t-butylpyrocatechol catalysed by Vanadium(III or IV) Complexes
Tatsuno, Yoshitaka,Tatsuda, Masanobu,Otsuka, Sei
, p. 1100 - 1101 (1982)
Oxygenation of 3,5-di-t-butylpyrocatechol (1) to the corresponding muconic acid anhydride (2) and 2-pyrone (3) is efficiently catalysed by vanadium(III or IV) complexes.
VANADIUM-CATECHOLATO COMPLEXES AS REACTION INTERMEDIATES IN THE VANADIUM CATALYZED OXYGENATION OF CATECHOLS
Tatsuno, Yoshitaka,Tatsuda, Masanobu,Otsuka, Sei,Tani, Kazuhide
, p. 1209 - 1212 (1984)
New vanadium-catecholato complexes containing a Schiff base ligand, (V(salen)(DBcatH)2)*1/2 CH2Cl2, (V(salen)(DBpyrH2)2)*1/2 H2O, (V(salen)(cat))*1/10 CH2Cl2, (V(salen)(Bcat))*H2O, (V(saldpt)(DB-catH))*CH2Cl2 were prepared and characterized by elemental analyses and spectroscopic methods.Their relationship to the vanadium(III or IV)-catalyzed oxygenation of catechol was discussed.
Kinetic and mechanistic studies of vanadium-based, extended catalytic lifetime catechol dioxygenases
Yin, Cindy-Xing,Finke, Richard G.
, p. 13988 - 13996 (2005)
Recently we showed that V-containing polyoxometalates such as (n-Bu 4N)7SiW9V3O40 or (n-Bu4N)9P2W15V3O 62, as well as eight other V-containing precatalysts tested, evolve to high-activity, long catalytic lifetime (≥30 000-100 000 total turnovers) 3,5-di-tert-butylcatechol (DTBC) dioxygenases in which Pierpont's complex [VO(DBSQ)(DTBC)]2 is apparently a common catalyst resting state [Yin, C.-X.; Finke, R. G. J. Am. Chem. Soc. 2005, 107, 9003-9013]. In a separate paper, autoxidation of DTBC to the corresponding benzoquinone and H 2O2 was shown to be a key to the catalyst evolution process: the H2O2, DTBC, and O2 plus virtually any V-based precatalyst tested form [VO(DBSQ)(DTBC)]2 under the catalytic conditions, that catalyst formation process being autocatalytic in H2O2. The resulting novel concept is that of an autoxidation-product-initiated dioxygenase [Yin, C.-X.; Sasaki, Y.; Finke, R. G. Inorg Chem. 2005, in press]. Herein the following questions about this record catalytic lifetime 3,5-di-tert-butylcatechol dioxygenase catalyst are explored: (i) What is the rate law for 3,5-di-tert-butylcatechol dioxygenation when one begins with Pierpont's [VO(DBSQ)(DTBC)]2? (ii) Does it support the hypothesis that this complex is a catalyst resting state or, perhaps, even the true catalyst? (iii) Can a mechanism be written from that information and from the knowledge in the dioxygenase literature? The results answer each of these questions and provide considerable mechanistic insight into the most catalytically active and long-lived DTBC dioxygenase catalyst presently known.
A novel iripodal ligand containing three different N-heterocyclic donor functions and its application in catechol dioxygenase mimicking
Wagner, Marit,Limberg, Christian,Tietz, Thomas
, p. 5567 - 5576 (2009)
We describe a novel chiral ligand, L, in which three different Ndonor functions are linked to a methoxymethine unit: a methylpyrazole derivative, a methylimidazole unit, and a pyridyl residue. Complexes with FeCl2, FeBr2, and FeClsu
Biomimetic extradiol cleavage of catechols: Insights into the enzyme mechanism
Ito,Que L.
, p. 1342 - 1344 (1997)
Quantitative extradiol cleavage of a catechol derivative is achieved by exposure of complex 1 to O2 in the presence of AgBF4 and an aromatic nitrogen base. These results provide insight into how the regiochemistry of oxidative cleavage may be controlled by the metal centers of the catechol dioxygenases.
Vanadium aminophenolates in catechol oxidation: Conformity with Finke's common catalyst hypothesis
Salonen, Pasi,Savela, Risto,Peuronen, Anssi,Lehtonen, Ari
supporting information, p. 6088 - 6099 (2021/05/19)
Six known aminophenolate vanadium complexes V1-V6 were examined in 3,5-di-tert-butylcatechol (1, 3,5-DTBC) oxidation. From the complexes V1-V5 have been previously shown to demonstrate catechol oxidase (catecholase) like behavior, catalytically oxidizing 1 to 3,5-di-tert-butyl-1,2-benzoquinone (2, 3,5-DTBQ). A critical re-evaluation of V1-V5, including V6 not assessed earlier, in the aerobic oxidation of 1 has revealed that several catechol dioxygenase products are obtained in addition to 2, which is produced partly by autoxidation. Mechanistic investigations into the V1-V6 catalyzed oxidation of 1 by EPR, negative mode ESI-MS and 51V NMR, in addition to semi-quantitative product distribution analyses with GC and column chromatography afford compelling evidence in support of the "common catalyst hypothesis"earlier proposed by Finke and co-workers. During the reaction, V1-V6 are partially converted in situ by H2O2 assisted leaching to vanadium catecholate complexes [V(3,5-DTBC)2(3,5-DTBSQ)] and [VO(3,5-DTBC)(3,5-DTBSQ)], where 3,5-DTBSQ = 3,5-di-tert-butyl-1,2-semiquinone, the latter of which has been implicated as the common true active catalyst in catechol dioxygenation as per the common catalyst hypothesis. The results herein suggest that vanadium aminophenolate complexes are sensitive to H2O2 mediated leaching in the presence of strong σ and π donating ligands such as 1 and 2. Furthermore, based on these results, the use of vanadium aminophenolate complexes as catechol oxidase mimics is not as warranted as previously understood.
Bioinspired copper(I) complexes that exhibit monooxygenase and catechol dioxygenase activity
Arnold, Aline,Metzinger, Ramona,Limberg, Christian
, p. 1198 - 1207 (2015/03/05)
New tripodal ligand L2 featuring three different pyridyl/imidazolyl-based N-donor units at a bridgehead C atom, from which one of the imidazolyl units is separated by a phenylene linker, was synthesized and investigated with regards to copper(I) complexation. The resulting complex [(L2)Cu]OTf (2OTf), the known complex [(L1)Cu]OTf (1OTf; L1 differs from L2 in that it lacks the phenylene spacer) and [(L3)Cu]OTf (3OTf), prepared from a known chiral, tripodal, N-donor ligand featuring pyridyl, pyrazolyl, and imidazolyl donors, were tested as catalysts for the oxidation of sodium 2,4-di-tert-butylphenolate (NaDTBP) with O2. Indeed, they mediated NaDTBP oxidation to give mainly the corresponding catecholate and quinone (Q). None of the complexes 1OTf, 2OTf, and 3OTf is superior to the others, as yields were comparable and, if the presence of protons is guaranteed by concomitant addition of the phenol DTBP, the oxidation can also be performed catalytically. For all complexes stoichiometric oxidations under certain conditions (concentrated solutions, high NaDTBP content) were found to also generate products typical for metal-mediated intradiol cleavage of the catecholate with O2. As shown representatively for 1OTf this dioxygenation sets in at a later stage of the reaction. Initially a copper species responsible for the monooxygenation must form from 1OTf/NaDTBP/O2, and only thereafter is the copper species responsible for dioxygenation formed and consumes Q as substrate. Hence, under these circumstances complexes 1OTf-3OTf show both monooxygenase and catechol dioxygenase activity.
