90-46-0Relevant articles and documents
A highly reactive P450 model compound I
Bell, Seth R.,Groves, John T.
, p. 9640 - 9641 (2009)
(Graph Presented) The detection and kinetic characterization of a cytochrome P450 model compound I, [OFeIV-4-TMPyP]+ (1), in aqueous solution shows extraordinary reaction rates for C-H hydroxylations. Stopped-flow spectrophotometric monitoring of the oxidation of Fe III-4-TMPyP with mCPBA revealed the intermediate 1, which displays a weak, blue-shifted Soret band at 402 nm and an absorbance at 673 nm, typical of a porphyrin π-radical cation. This intermediate was subsequently transformed into the well-characterized OFeIV-4-TMPyP. Global analysis afforded a second-order rate constant k1 = (1.59 ± 0.06) × 10 7 M-1 s-1 for the formation of 1 followed by a first-order decay with k2 = 8.8 ± 0.1 s-1. 1H and 13C NMR determined 9-xanthydrol to be the major product (～90% yield) of xanthene oxidation by 1. Electrospray ionization mass spectrometry carried out in 47.5% 18OH2 indicated 21% 18O incorporation, consistent with an oxygen-rebound reaction scenario. Xanthene/xanthene-d2 revealed a modest kinetic isotope effect, kH/kD = 2.1. Xanthene hydroxylation by 1 occurred with a very large second-order rate constant k3 = (3.6 ± 0.3) × 106 M-1 s-1. Similar reactions of fluorene-4-carboxylic acid and 4-isopropyl- and 4-ethylbenzoic acid also gave high rates for C-H hydroxylation that correlated well with the scissile C-H bond energy, indicating a homolytic hydrogen abstraction transition state. Mapping the observed rate constants for C-H bond cleavage onto the Bronsted- Evans-Polanyi relationship for similar substrates determined the H-OFe IV-4-TMPyP bond dissociation energy to be ～100 kcal/mol. The high kinetic reactivity observed for 1 is suggested to result from a high porphyrin redox potential and spin-state-crossing phenomena. More generally, subtle charge modulation at the active site may result in high reactivity of a cytochrome P450 compound I.
Meso-Substitution Activates Oxoiron(IV) Porphyrin π-Cation Radical Complex More Than Pyrrole-β-Substitution for Atom Transfer Reaction
Fukui, Nami,Ueno, Kanako,Hada, Masahiko,Fujii, Hiroshi
supporting information, p. 3207 - 3217 (2021/03/01)
There have been two known categories of porphyrins: a meso-substituted porphyrin like meso-tetramesitylporphyrin (TMP) and a pyrrole-β-substituted porphyrin like native porphyrins and 2,7,12,17-tetramethyl-3,8,13,18-tetramesitylporphyrin (TMTMP). To reveal the chemical and biological function of native hemes, we compare the reactivity of the oxoiron(IV) porphyrin π-cation radical complex (Compound I) of TMP (TMP-I) with that of TMTMP (TMTMP-I) for epoxidation, hydrogen abstraction, hydroxylation, sulfoxidation, and demethylation reactions. Kinetic analysis of these reactions indicated that TMP-I is much more reactive than TMTMP-I when the substrate is not sterically bulky. However, as the substrate is sterically bulkier, the difference of the reactivity between TMP-I and TMTMP-I becomes smaller, and the reactivity of TMP-I is comparable to that of TMTMP-I for a sterically hindered substrate. Since the redox potential of TMP-I is almost the same as that of TMTMP-I, we conclude that TMP-I is intrinsically more reactive than TMTMP-I for these atom transfer reactions, but the steric effect of TMP-I is stronger than that of TMTMP-I. This is contrary to the previous result for the single electron transfer reaction: TMTMP-I is faster than TMP-I. DFT calculations indicate that the orbital energies of the Fe=O moiety for TMTMP-I are higher than those for TMP-I. The difference in steric effect between TMP-I and TMTMP-I is explained by the distance from the mesityl group to the oxo ligand of Compound I. Significance of the pyrrole-β-substituted structure of the hemes in native enzymes is also discussed on the basis of this study.
Manganese(Ⅲ)-iodosylbenzene complex, preparation method thereof and oxidant comprising the same
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Paragraph 0130-0136; 0141; 0166, (2020/09/22)
The present invention relates to a manganese(III)-iodosylbenzene complex, a preparation method thereof, and an oxidant comprising the same. The manganese(III)-iodosylbenzene complex provided in one aspect of the present invention has an effect of inducing a hydrogen atom abstraction (HAA) reaction of cyclohexadiene, dihydroanthracene and xanthine, and an oxygen atom transfer (OAT) reaction of thioanisole and stilbene with excellent electrophilic reactivity. The manganese(III)-iodosylbenzene complex is represented by a compound of formula 1: [Mn^III(L)(OIPh)(OH)]^2+.COPYRIGHT KIPO 2020
Asymmetric synthesis of (2S,3S)-3-Me-glutamine and (R)-allo-threonine derivatives proper for solid-phase peptide coupling
Tokairin, Yoshinori,Soloshonok, Vadim A.,Moriwaki, Hiroki,Konno, Hiroyuki
, p. 419 - 432 (2018/11/27)
Practical new routes for preparation of (2S,3S)-3-Me-glutamine and (R)-allo-threonine derivatives, the key structural components of cytotoxic marine peptides callipeltin O and Q, suitable for the Fmoc-SPPS, were developed. (2S,3S)-Fmoc-3-Me-Gln(Xan)-OH was synthesized via Michael addition reactions of Ni (II) complex of chiral Gly-Schiff base; while Fmoc-(R)-allo-Thr-OH was prepared using chiral Ni (II) complex-assisted α-epimerization methodology, starting form (S)-Thr(tBu)-OH.
CoI-Catalyzed Barbier Reactions of Aromatic Halides with Aromatic Aldehydes and Imines
Presset, Marc,Paul, Jér?me,Cherif, Ghania Nait,Ratnam, Nisanthan,Laloi, Nicolas,Léonel, Eric,Gosmini, Corinne,Le Gall, Erwan
supporting information, p. 4491 - 4495 (2019/02/27)
The reductive Barbier coupling of aromatic halides and electrophiles has been achieved using a CoBr2/1,10-phenanthroline catalytic system and over stoichiometric amounts of zinc. The reaction displayed a broad scope of substrates, including (hetero)aryl chlorides as pro-nucleophiles and aldehydes or imines as electrophiles, leading to diarylmethanols and diarylmethylamines in moderate to excellent yields, respectively.
Earth-Abundant Mixed-Metal Catalysts for Hydrocarbon Oxygenation
Pankhurst, James R.,Curcio, Massimiliano,Sproules, Stephen,Lloyd-Jones, Guy C.,Love, Jason B.
supporting information, p. 5915 - 5928 (2018/05/28)
The oxygenation of aliphatic and aromatic hydrocarbons using earth-abundant Fe and Cu catalysts and "green" oxidants such as hydrogen peroxide is becoming increasingly important to atom-economical chemical processing. In light of this, we describe that dinuclear CuII complexes of pyrrolic Schiff-base macrocycles, in combination with ferric chloride (FeCl3), catalyze the oxygenation of π-activated benzylic substrates with hydroperoxide oxidants at room temperature and low loadings, representing a novel design in oxidation catalysis. Mass spectrometry and extended X-ray absorption fine structure analysis indicate that a cooperative action between CuII and FeIII occurs, most likely because of the interaction of FeCl3 or FeCl4- with the dinuclear CuII macrocycle. Voltammetric measurements highlight a modulation of both CuII and FeIII redox potentials in this adduct, but electron paramagnetic resonance spectroscopy indicates that any Cu-Fe intermetallic interaction is weak. High ketone/alcohol product ratios, a small reaction constant (Hammett analysis), and small kinetic isotope effect for H-atom abstraction point toward a free-radical reaction. However, the lack of reactivity with cyclohexane, oxidation of 9,10-dihydroanthracene, oxygenation by the hydroperoxide MPPH (radical mechanistic probe), and oxygenation in dinitrogen-purge experiments indicate a metal-based reaction. Through detailed reaction monitoring and associated kinetic modeling, a network of oxidation pathways is proposed that includes "well-disguised" radical chemistry via the formation of metal-associated radical intermediates.
Structure and Reactivity of a Mononuclear Nonheme Manganese(III)-Iodosylarene Complex
Jeong, Donghyun,Ohta, Takehiro,Cho, Jaeheung
supporting information, p. 16037 - 16041 (2018/12/13)
Transition metal-iodosylarene complexes have been proposed to be key intermediates in the catalytic cycles of metal catalysts with iodosylarene. We report the first X-ray crystal structure and spectroscopic characterization of a mononuclear nonheme manganese(III)-iodosylarene complex with a tetradentate macrocyclic ligand, [MnIII(TBDAP)(OIPh)(OH)]2+ (2). The manganese(III)-iodosylarene complex is capable of conducting various oxidation reactions with organic substrates, such as C-H bond activation, sulfoxidation and epoxidation. Kinetic studies including isotope labeling experiments and Hammett correlation demonstrate the electrophilic character on the Mn-iodosylarene adduct. This novel intermediate would be prominently valuable for expanding the chemistry of transition metal catalysts.
Preparation method of xanthydrol
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Paragraph 0008; 0009, (2018/03/26)
The invention relates to the chemical field, in particular to a preparation method of xanthydrol. The method comprises the steps as follows: 31.3 g of o-chlorobenzoic acid, 37.6 g of phenol, 5.53 g ofpotassium carbonate, 16.2 mL of pyridine, 2 g of copper powder, 2 g of cuprous iodide and 200 mL of water are added to a 500 mL three-neck flask, the mixture is stirred mechanically, subjected to reflux for 2 h and cooled to the room temperature, diluted hydrochloric acid is added to make a reaction solution to be acid, a solid is filtered out, washed and dissolved in a 10% sodium hydroxide aqueous solution, the obtained solution is added to a mixed solution of acetic acid and water for precipitation of a solid, the obtained solid is recrystallized with the mixed solution of acetic acid and water, and 36.4 g of white crystal o-phenoxybenzoic acid is obtained; 20 g of o-phenoxybenzoic acid and 80 mL of tetrahydrofuran are added to a 150 mL three-neck flask, the mixture is stirred mechanically and cooled to 0 DEG C, 23 mL of a catalyst is dropwise added at the temperature of 0 DEG C, the obtained mixture is heated for reflux for 30 min after addition and cooled to the room temperature,and ice water is added to a reaction solution. The technological process is simple and safe to operate, the production cost is reduced, environmental pollution is avoided in the reaction process, andthe product quality is improved.
Synthetic method of xanthene-9-formic acid
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Paragraph 0035; 0036; 0037; 0044; 0045; 0046, (2017/12/09)
The invention discloses a synthetic method of xanthene-9-formic acid, which belongs to the field of chemical synthesis. The method comprises the following steps: xanthone is taken as a raw material, then is reduced to xanthydrol under alkaline condition by zinc dust, then the xanthydrol is subjected to a halogenated reaction to obtain the halogenated xanthene, then under effect of a catalyst, a cyanidation reaction is generated to obtain 9-cyan xanthene, through alkali hydrolysis, organic impurity is removed through extraction of an organic solvent, a xanthene-9-formate aqueous solution is obtained, and a xanthene-9-formic acid product is obtained through a neutralization reaction. The method has the advantages of simple operation and safe technology, the xanthene-9-formic acid with high purity is obtained without refining, and the method is easy and effective for industrial production.
Thioether compounds and synthetic method thereof
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Paragraph 0036, (2017/08/29)
The invention discloses thioether compounds and a synthetic method thereof. The structure of the thioether compounds is shown in formula I, wherein X and R1-R10 are defined in the specification. According to the synthetic route, a product is finally synthesized from 9H-Xxanthene-9-one through hydrogenation, thio-etherification, hydrogen removal and alkylation. The thioether compounds can have a certain trigger action in radical polymerization and can be subjected to a reversible coupling-cleavage reaction with chain propagation radicals, so that the chain propagation radicals form dormant species, and polymerization shows certain controllability. Meanwhile, compared with reagents used in the traditional 'active'-controllable radical polymerization system, the compounds have the advantages of being nontoxic, odorless, colorless and free of metal ions, have better solubility without additional ligands and the like, and have better application prospect in the field of radical polymerization.
