- Trinuclear Mn2+/Zn2+based microporous coordination polymers as efficient catalysts foripso-hydroxylation of boronic acids
-
Two microporous coordination polymers based on hourglass trinuclear building units, [Mn3(bpdc)3(bpy)]·2DMF and [Zn3(bpdc)3(bpy)]·2DMF·4H2O (bpdc = 4,4′-biphenyl dicarboxylic acid, bpy = 4,4′-bipyridine), have been synthesized under solvothermal conditions employing DMF as the solvent. Each structure consists of two crystallographically distinct M2+(M1 and M2) centers that are connectedviacarboxylate bridges from six bpdc ligands, generating a trinuclear metal cluster, [M3(bpdc)3(bpy)]. Cluster representation of the structure resulted in an interpenetrated net of rarehextopological type. Catalytic activities of the CPs have been assessed for the oxidative hydroxylation of phenylboronic acids (PBAs) using aqueous hydrogen peroxide (H2O2). Various substituted aryl/hetero-arylboronic acids RB(OH)2[R = phenyl, 2,4-difluorophenyl, 4-aminophenyl, 2-thiopheneetc.] underwentipso-hydroxylation smoothly at room temperature to generate the corresponding phenols in excellent yields. The main advantages of this protocol are the aqueous medium reaction, heterogeneous catalytic system, and short reaction time with excellent yield.
- Bora, Sanchay J.,Dutta, Anurag,Goswami, Shyam,Guha, Ankur K.,Paul, Rima,Thakur, Ashim J.
-
p. 5454 - 5462
(2020/05/16)
-
- Tetrahydroquinoline N-oxidation derivative as well as preparation method and application thereof
-
The invention relates to tetrahydroquinoline N-oxidation derivative as well as a preparation method and application thereof. The invention relates to a compound shown in a general formula (I) in the specification, a preparation method of the compound, a pharmaceutical composition containing the compound, and application of the compound as a BRD4 inhibitor in treating cancer, inflammation, chronicliver diseases, diabetes mellitus, cardiovascular diseases, AIDS and other related diseases.
- -
-
Paragraph 0165; 0171; 0351-0358
(2019/07/04)
-
- Size-tunable ZnO nanotapes as an efficient catalyst for oxidative chemoselective C–B bond cleavage of arylboronic acids
-
Herein, we report a simple but effective chemical approach for the synthesis of size-tunable ZnO nanotapes by precipitation method in the presence of phytochemicals present in the flower extract of Lantana camara plant. The electron microscopic study confirmed that the size of ZnO nanotapes can be systematically controlled by varying the concentration of either flower extract or metal ions and the flower extract played the key role in controlling the growth of ZnO nanotapes. The phase and crystalline analysis was carried out by X-ray diffraction method which indicated that ZnO nanostructures are highly crystalline in nature and are free from any impurities. The synthesized ZnO nanostructures exhibited interesting optical properties as investigated by UV–vis absorption and photoluminescence spectroscopy. Further the surface functionalities affect the optical properties of ZnO nanostructures which possess relatively strong UV emissions; a blue emission and a green emission. The synthesized ZnO nanostructures showed excellent catalytic properties in the ipso-hydroxylation of different aryl/ hetero-arylboronic acid to phenol in a relatively greener reaction conditions. These catalysts are highly stable and are re-usable upto six cycles of ipso-hydroxylation without losing its catalytic properties.
- Phukan, Shreemoyee,Mahanta, Abhijit,Rashid, Md. Harunar
-
-
- Promotional effect of ionic liquids in the electrophilic fluorination of phenols
-
The influence of a stoichiometric amount of ionic liquids (IL) on the fluorination of phenols in various solvents has been studied. The fluorination of phenol, 1-naphthol and resorcinol was carried out using 1-chloromethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate) (F-TEDA-BF4, Selectfluor) with the formation of 2-fluoro-, 4-fluorophenol, 2-fluoro-, 4-fluoronaphthol and 4-fluoro-, 4,6-difluoro-benzene-1,3-diol as the main products. The use of a stoichiometric amount of ionic liquid as an additive results in acceleration of the reactions. The effect is most significant at low temperatures. It has been found that solvent polarity has an essential effect on the difference in yields of fluoroproducts obtained in the presence of IL and without it.
- Borodkin, Gennady I.,Elanov, Innokenty R.,Shubin, Vyacheslav G.
-
-
- Process for preparing phenol fluoride by amine catalytic method
-
The invention relates to a process for preparing phenol fluoride by amine catalytic method and belongs to the technical field of chemical synthesis.The process comprises: adding phenol and a catalyst sequentially into a reactor for heating, introducing fluorine-nitrogen mixed gas into the reactor for reacting, purging with nitrogen after reacting to obtain crude phenol fluoride, charging purging gas and reaction tail gas sequentially into an activated carbon absorber and a solid sodium lime absorber for adsorption, discharging finally obtained non-condensable gas at a great height, rectifying and separating the crude phenol fluoride to obtain o-fluorophenol, p-fluorophenol, 2,4-difluorophenol and 2,6-difluorophenol.The problem that an existing preparation process has low product yield, high solvent consumption, high cost and environmental pollution is solved herein, the process has the advantages of material conversion completeness, little byproduct and low production cost, no additional solvent is added to maintain a certain temperature range, cost is saved, and solvent loss is reduced.
- -
-
Paragraph 0028; 0030; 0038; 0054-0058
(2017/04/03)
-
- Biosilica as an efficient heterogeneous catalyst for ipso-hydroxylation of arylboronic acids
-
A mild and efficient protocol for the conversion of arylboronic acids to phenol via ipso-hydroxylation has been developed using aqueous hydrogen peroxide as oxidant and biosilica as heterogeneous catalyst. The recyclability of the catalyst is also evaluated and could be reused up to six consecutive cycles without a significant loss in catalytic activity.
- Mahanta, Abhijit,Adhikari, Pooja,Bora, Utpal,Thakur, Ashim Jyoti
-
supporting information
p. 1780 - 1783
(2015/03/30)
-
- Catalytic defluorination of perfluorinated aromatics under oxidative conditions using N-bridged diiron phthalocyanine
-
Carbon-fluorine bonds are the strongest single bonds in organic chemistry, making activation and cleavage usually associated with organometallic and reductive approaches particularly difficult. We describe here an efficient defluorination of poly- and perfluorinated aromatics under oxidative conditions catalyzed by the μ-nitrido diiron phthalocyanine complex [(Pc)Fe III(μ-N)FeIV(Pc)] under mild conditions (hydrogen peroxide as the oxidant, near-ambient temperatures). The reaction proceeds via the formation of a high-valent diiron phthalocyanine radical cation complex with fluoride axial ligands, [(Pc)(F)FeIV(μ-N)FeIV(F) (Pc+?)], which was isolated and characterized by UV-vis, EPR, 19F NMR, Fe K-edge EXAFS, XANES, and Kβ X-ray emission spectroscopy, ESI-MS, and electrochemical techniques. A wide range of per- and polyfluorinated aromatics (21 examples), including C6F6, C6F5CF3, C6F5CN, and C6F5NO2, were defluorinated with high conversions and high turnover numbers. [(Pc)FeIII(μ-N)Fe IV(Pc)] immobilized on a carbon support showed increased catalytic activity in heterogeneous defluorination in water, providing up to 4825 C-F cleavages per catalyst molecule. The μ-nitrido diiron structure is essential for the oxidative defluorination. Intramolecular competitive reactions using C6F3Cl3 and C6F3H 3 probes indicated preferential transformation of C-F bonds with respect to C-Cl and C-H bonds. On the basis of the available data, mechanistic issues of this unusual reactivity are discussed and a tentative mechanism of defluorination under oxidative conditions is proposed.
- Colomban, Cédric,Kudrik, Evgenij V.,Afanasiev, Pavel,Sorokin, Alexander B.
-
supporting information
p. 11321 - 11330
(2014/11/07)
-
- Oxidation of organotrifluoroborates via oxone
-
A method for the oxidation of organotrifluoroborates using Oxone was developed. A variety of aryl-, heteroaryl-, alkenyl-, and alkyltrifluoroborates were converted into the corresponding oxidized products in excellent yields. This method proved to be tolerant of a broad range of functional groups, and in secondary alkyl substrates it was demonstrated to be completely stereospecific.
- Molander, Gary A.,Cavalcanti, Livia N.
-
experimental part
p. 623 - 630
(2011/03/20)
-
- Fluorination of aromatic compounds with N-fluorobenzenesulfonimide under solvent-free conditions
-
Reactions of N-fluorobenzenesulfonimide with methylbenzenes, phenols, and phenol ethers were studied under solvent-free conditions. The rate constant ratio for the reactions with mesitylene and durene indicates polar mechanism of the process. Solvent-free fluorination of aromatic compounds with N-fluorobenzenesulfonimide in some cases is more selective than reactions with other N-F reagents in a solvent.
- Andreev,Borodkin,Shubin
-
scheme or table
p. 1468 - 1473
(2010/03/24)
-
- ALPHA ARYL OR HETEROARYL METHYL BETA PIPERIDINO PROPANAMIDE COMPOUNDS AS ORL1-RECEPTOR ANTAGONIST
-
This invention provides the compounds of formula (I): or a pharmaceutically acceptable ester of such compound, or a pharmaceutically acceptable salt thereof, wherein Ri and R2 independently represent a hydrogen atom or the like; R3 represents a hydrogen atom, or the like; R4 represents a hydrogen atom or the like; (formula II) represents one of the following or the like; R5 represents an aryl group having from 6 to 10 ring atoms or the like; X represents an oxygen atom, or the like; Y represents an oxgen atom or the like and n represents an integer 0, 1 or 2. These compounds have ORL1-receptor antagonist activity; and therefore, are useful to treat diseases or conditions such as pain, various CNS diseases etc.
- -
-
Page/Page column 78-79
(2010/02/14)
-
- Enzymatic Baeyer-Villiger oxidation of benzaldehydes
-
The selectivity of the chemical Baeyer-Villiger oxidation of benzaldehydes depends on steric and electronic factors, the type of oxidizing agent and the reaction conditions. Here we report on the enzymatic Baeyer-Villiger oxidation of fluorobenzaldehydes
- Moonen, Marielle J. H.,Westphal, Adrie H.,Rietjens, Ivonne M. C. M.,Van Berkel, Willem J. H.
-
p. 1027 - 1034
(2007/10/03)
-
- Imidazo heterocyclic compounds
-
A novel class of imidazo heterocyclic compounds, pharmaceutical compositions comprising them and use thereof in the treatment and/or prevention of diseases and disorders related to the histamine H3 receptor. More particularly, the compounds are useful for the treatment and/or prevention of diseases and disorders in which an interaction with the histamine H3 receptor is beneficial.
- -
-
-
- Synthesis, Properties, and Reactivity of N,N'-Difluorobipyridinium and Related Salts and Their Applications as Reactive and Easy-To-Handle Electrophilic Fluorinating Agents with High Effective Fluorine Content
-
N,N′-Difluoro-2,2′-, -2,4′-, -3,3′-, -4,4′-bipyridinium and substituted N,N′-difluoro-2,2′-bipyridinmm bis(triflates), bis(tetrafluoroborates), bis(hexafluorophosphates), and bis(hexafluoroantimonates) 1-9 were synthesized in high yields by the direct fluorination of a mixture of a bipyridyl and a Lewis acid, a Br?nsted acid, or the alkali metal salt of an acid. The higher homologues, trimer 10 and polymer 11, were also synthesized. Unsubstituted or electron-donating group-substituted N,N′- difluorobipyridinium salts are stable nonhygroscopic crystals, while the electron-withdrawing group- substituted N,N′-diflurobipyridinium salts 3, 5, and 6 are moisture-sensitive crystals. Hydrolysis of 1b in boiling water gave 3,3′-dihydroxy-2,2′-bipyridyl. The reactivity determination indicated that the fluorinating capability decreased in the order 2,2′- ? 2,4' > 3,3′- ≈ 4,4′-isomer ? N-fluoropyridinium salt and that the two N-F moieties in a molecule were effective for fluorination. This fluorination occurred in a step-by-step manner, and the reactivity difference between the first and second fluorinations was very small. N,N′-Difluoro-2,2′-bipyridinium bis(tetrafluoroborate) (1b) is thus shown to be a highly reactive and easy-to-handle electrophilic fluorinating agent with the high effective fluorine content (103.3 g/kg) for preparing many fluoro organic compounds.
- Umemoto, Teruo,Nagayoshi, Masayuki,Adachi, Kenji,Tomizawa, Ginjiro
-
p. 3379 - 3385
(2007/10/03)
-
- Regiospecific hydroxylation in aromatic series by the organosilicon pathway
-
Regiospecific hydroxylation of functional arylsilanes by hydrogen peroxide (30percent) or by bis(trimethylsilyl) peroxide, in the presence of a stoichiometric amount of fluoride ions, gives the corresponding phenols in good yields. regiospecific hydroxylation / phenol / hydrogen peroxide / bis(trimethylsilyl) peroxide / arylsilane
- Prouilhac-Cros, Sylvie,Babin, Pierre,Bennetau, Bernard,Dunogues, Jacques
-
p. 513 - 516
(2007/10/02)
-
- Influence of the type of halogen substituent on in vivo and in vitro phase II metabolism of 2-fluoro-4-halophenol metabolites formed from 3-halo-fluorobenzenes
-
The influence of a change in the type of halogen substituent on phase II metabolism of 2-fluoro-4-halophenol metabolites formed from 3-halo-fluorobenzenes was studied in vivo and in vitro using 19F nmr and spectroscopic assays. The ratio of sulphation to glucuronidation of 2-fluoro-4-halophenol metabolites formed from 3-halofluorobenzenes decreased from 48 to 13 to 6 when the halogen substituent varied from fluorine to chlorine to bromine. When the 2-fluoro-4-halophenols themselves were administered to the rats, the ratio of sulphation to glucuronidation was not affected by the type of halogen substituent at C4 and at a constant value of 0.6, i.e. significantly lower. Kinetic data for P450 catalysed hydroxylation of the 3-halo-fluorobenzenes and for sulphation and glucuronidation of their 2-fluoro-4-halophenol metabolites were obtained from in vitro microsomal and cytosolic incubations. These data demonstrate that the effects of varying the halogen substituent on phase II metabolism of the 2-fluoro-4-halophenol metabolites can be mainly ascribed to an apparently decreased K(m) for the glucuronidation of the 2-fluoro-4-halophenols with a change in the halo substituent from fluorine to chlorine to bromine. Results from calculations on electronic and structural characteristics of the three 4-halo-2-fluorophenols demonstrate that the best explanation for the decrease in the apparent K(m) of the glucuronidation from 2,4-difluoro- to 4-chloro-2-fluoro- to 4-bromo-2-fluorophenol might be an increase in the hydrophobicity of the phenol. An increase in the hydrophobicity of the phenol would provide an increased possibility for substrate accumulation in the hydrophobic membrane environment of the UDP-glucuronyltransferases, resulting in an apparently decreased K(m).
- Soffers,Veeger,Rietjens
-
p. 759 - 774
(2007/10/03)
-
- Power and structure-variable fluorinating agents. The N-fluoropyridinium salt system
-
The usefulness of the N-fluoropyridinium salt system as a source of fluorinating agents was examined by using substituted or unsubstituted N-fluoropyridinium triflates 1-11, N-fluoropyridinium salts possessing other counteranions 1a-d and 3a, and the counteranion-bound salts, N-fluoropyridinium-2-sulfonates 12 and 13. Electrophilic fluorinating power was found to vary remarkably according to the electronic nature of the ring substituents. This power increased as the electron density of positive nitrogen sites decreased, and this was correlated to the pKa values of the corresponding pyridines. By virtue of this variation, it was possible to fluorinate a wide range of nucleophilic substrates differing in reactivity. It is thus possible to fluorinate aromatics, carbanions, active methylene compounds, enol alkyl or silyl ethers, vinyl acetates, ketene silyl acetals, and olefins through the proper use of salts pentachloro 6 through 2,4,6-trimethyl 2, their power decreasing in this order. All the reactions could be explained on the basis of a one-electron-transfer mechanism. N-Fluoropyridinium salts showed high chemoselectivity in fluorination, the extent depending on the reactive moiety. In consideration of these Findings, selective 9α-fluorination of steroids was carried out by reacting 1 with tris(trimethylsilyl ether) 73 of a triketo steroid. Regio- or stereoselectivity in fluorination was determined by a N-fluoropyridinium salt structure. Steric bulkiness of the N-F surroundings hindered the ortho fluorination of phenols and aniline derivatives, while the capacity for hydrogen bonding on the part of the counteranions prompted this process, and the counteranion-bound salts 12 and 13 underwent this fluorination exclusively or almost so. Both bulky N-fluoropyridinium triflates 2 and 7 preferentially attacked the 6-position of the conjugated vinyl ester of a steroid from the unhindered β-direction to give a thermally unstable 6β-fluoro isomer. On the basis of these results, N-fluoropyridinium salts may be concluded to constitute a system that can serve as a source of the most ideal fluorinating agents for conducting desired selective fluorination through fluorinating capacity or structural alteration.
- Umemoto, Teruo,Fukami, Shinji,Tomizawa, Ginjiro,Harasawa, Kikuko,Kawada, Kosuke,Tomita, Kyoichi
-
p. 8563 - 8575
(2007/10/02)
-
- N-FLUOROPYRIDINIUM TRIFLATE AND ITS DERIVATES: USEFUL FLUORINATING AGENTS
-
N-Fluoropyridinium triflate and its derivates, stable and nonhygroscopic crystals, were found to be widely applicable reagents for mild and selective fluorination of a variety of organic compounds.
- Umemoto, Teruo,Kawada, Kosuke,Tomita, Kyoichi
-
p. 4465 - 4468
(2007/10/02)
-
