- Annulative Morita-Baylis-Hillman reaction to synthesise chiral dibenzocycloheptanes
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We describe the first metal-free and organocatalytic strategy to access highly functionalised dibenzocycloheptanesviaa phosphine-promoted annulative Morita-Baylis-Hillman (MBH) reaction. The method is manipulated to access to chiral dibenzocycloheptanes as well. This work represents a rare entry for the construction of seven-membered carbocyclesviathe MBH route. The realisation of several bioactive molecules possessing the dibenzocycloheptane core makes this an attractive strategy.
- Mondal, Atanu,Ramasastry, S. S. V.,Shivangi,Tung, Pinku,Wagulde, Siddhant V.
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supporting information
p. 9260 - 9263
(2021/09/20)
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- Discovery of 3-aryl substituted benzoxaboroles as broad-spectrum inhibitors of serine- and metallo-β-lactamases
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The production of β-lactamases represents the main cause of resistance to clinically important β-lactam antibiotics. Boron containing compounds have been demonstrated as promising broad-spectrum β-lactamase inhibitors to combat β-lactam resistance. Here we report a series of 3-aryl substituted benzoxaborole derivatives, which manifested broad-spectrum inhibition to representative serine-β-lactamases (SBLs) and metallo-β-lactamases (MBLs). The most potent inhibitor 9f displayed an IC50 value of 86 nM to KPC-2 SBL and micromolar inhibitory activity towards other tested enzymes. Cell-based assays further revealed that 9f was able to significantly reduce the MICs of meropenem in clinically isolated KPC-2-producing bacterial strains and it showed no apparent toxicity in HEK293T cells.
- Yan, Yu-Hang,Li, Zhao-Feng,Ning, Xiang-Li,Deng, Ji,Yu, Jun-Lin,Luo, Yubin,Wang, Zhenling,Li, Guo,Li, Guo-Bo,Xiao, You-Cai
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supporting information
(2021/04/12)
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- Design and enantioselective synthesis of 3-(α-acrylic acid) benzoxaboroles to combat carbapenemase resistance
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Chiral 3-substituted benzoxaboroles were designed as carbapenemase inhibitors and efficiently synthesisedviaasymmetric Morita-Baylis-Hillman reaction. Some of the benzoxaboroles were potent inhibitors of clinically relevant carbapenemases and restored the activity of meropenem in bacteria harbouring these enzymes. Crystallographic analyses validate the proposed mechanism of binding to carbapenemases,i.e.in a manner relating to their antibiotic substrates. The results illustrate how combining a structure-based design approach with asymmetric catalysis can efficiently lead to potent β-lactamase inhibitors and provide a starting point to develop drugs combatting carbapenemases.
- Chen, Fener,Chen, Xiao-Pan,Deng, Ji,Li, Gen,Li, Guo-Bo,Schofield, Christopher J.,Xiao, You-Cai,Yan, Yu-Hang,Yu, Jun-Lin,Zhu, Kai-Rong,Brem, Jürgen
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supporting information
p. 7709 - 7712
(2021/08/09)
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- Sustainable Passerini-tetrazole three component reaction (PT-3CR): selective synthesis of oxaborol-tetrazoles
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A sustainable catalyst- and solvent-free Passerini-tetrazole three component reaction (PT-3CR) has been developed for the selective synthesis of benzoxaborol-tetrazoles for the first time. The synthetic potential of oxaboroles was demonstrated towards various functionalized tetrazoles, which are otherwise difficult to achieve through conventional PT-3CR from aromatic aldehydes/ketones. The reaction features high practicality, broad substrate scope and excellent yields (80-98%). Preliminary results of the asymmetric PT-3CR are also shown for the synthesis of chiral benzoxaboroles.
- Singh, Akansha,Kumar, Ravindra
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supporting information
p. 9708 - 9711
(2021/09/30)
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- Tuning the exchange dynamics of boronic acid hydrazones and oximes with pH and redox control
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Dynamic bonds continually form and dissociate at equilibrium. Carbonyl compounds with proximal boronic acids, including 2-formylphenylboronic acid (2-FPBA), have been reported to form highly dynamic covalent hydrazone and oxime bonds in physiological conditions, but strategies to tune the dynamics have not yet been reported. Here, we characterize the dynamics of 2-FPBA-derived hydrazones and oximes and account for both the rapid rate of formation (~102-103M?1s?1) and the relatively fast rate of hydrolysis (~10?4s?1) at physiological pH. We further show that these substrates undergo exchange with α-nucleophiles, which can be reversibly paused and restarted with pH control. Finally, we show that oxidation of the arylboronic acid effectively abolishes the rapid dynamics, which slows the forward reaction by more than 30?000 times and increases the hydrolytic half-life from 50 minutes to 6 months at physiological pH. These results set the stage to explore these linkages in dynamic combinatorial libraries, reversible bioconjugation, and self-healing materials.
- Han, Gun Su,Domaille, Dylan W.
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supporting information
p. 4986 - 4991
(2021/06/16)
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- Quinoline diamine-containing fourth subgroup metal complex and application thereof
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The invention relates to the technical field of olefin polymerization catalysts, and particularly discloses a quinoline diamine-containing fourth subgroup metal complex and application thereof. The quinoline diamine-containing fourth subgroup metal complex has the following structure: the quinoline diamine-containing fourth subgroup metal complex provided by the invention can catalyze ethylene homopolymerisation with high activity to obtain polyethylene with high molecular weight, and catalyze ethylene and [alpha]-olefin with high activity to copolymerize to generate a copolymer with medium to high molecular weight and insertion amount; and therefore, the problem that an existing olefin polymerization catalyst cannot generate a high-molecular-weight polymer while improving the catalytic activity is solved, and the olefin polymerization catalyst has a wide application prospect.
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Paragraph 0048-0050
(2021/04/07)
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- Tris(2-carboxyethyl)phosphine promotes hydrolysis of iminoboronates
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Iminoboronates are stable and formed fast. Their B[sbnd]N bonds could be reverted by some endogenous biological molecules. The reversible characteristic attracts significant attention in biological and chemical fields. Although synthesis of iminoboronates is well-studied, less efforts have been devoted to disconnecting the units. Here, a series of selected compounds were screened to evaluate their hydrolytic capability of iminoboronates by 1H NMR or 11B NMR detection. Tris(2-carboxyethyl)phosphine (TCEP), was emerged as an excellent reagent, which decomposed most iminoboronates in short time with high yields. In addition, TCEP is also able to hydrolyze hydrazones and oximes with moderate yields.
- Liu, Xiaoyu,Li, Zhihong,Xu, Hongtao,Zhan, Yuexiong,Ma, Peixiang,Chen, Hongli,Jiang, Biao
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p. 3101 - 3106
(2017/07/18)
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- A process for preparing aldehyde group benzene boric acid
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The invention discloses a method for preparing formyl phenylboronic acid, which comprises the following steps: heating halogenated phenylboronic acid in toluene or heptane under reflux for dewatering to form a tripolymer, mixing the tripolymer with dimethylformamide, dropwisely adding n-butyllithium at low temperature to react by a one-pot process, hydrolyzing with hydrochloric acid, and recrystallizing to obtain the formyl phenylboronic acid. The method is simple to operate, avoids the process of separating the intermediate after formyl protection in the conventional technique, has high universality, can obtain favorable yield for ortho-, meta- and para- formyl phenylboronic acids, and is beneficial to scale-up production.
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Paragraph 0028; 0031; 0032
(2017/07/04)
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- Synthesis of naphthalene ring derivatives and Benzoheterocycles the method of the compound
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The invention discloses a method for synthesizing naphthalene derivative and benzo-heterocycle compounds. The method is realized by promoting a reaction similar to Mortia-Baylis-Hillman between aryl aldehyde having alpha, beta-unsaturated ester on ortho-position and ketone compounds under the catalysis action of tertiary amine and tertiary phosphine organic small molecular catalysts, so as to remove a molecule of H2O, so that the naphthalene derivative or benzo-heterocycle compounds are generated. The method disclosed by the invention is simple in operation step, cheap and easily available in adopted catalysts and harmless to environment, and a series of naphthalene derivative and benzo-heterocycle compounds are synthesized with relatively high yield.
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Paragraph 0021; 0022
(2016/10/10)
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- Boronic acids facilitate rapid oxime condensations at neutral pH
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We report here the discovery and development of boron-assisted oxime formation as a powerful connective reaction for chemical biology. Oximes proximal to boronic acids form in neutral aqueous buffer with rate constants of more than 104 M-1
- Schmidt, Pascal,Stress, Cedric,Gillingham, Dennis
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p. 3329 - 3333
(2015/05/27)
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- Highly fluorescent, π-extended indenopyrido[2,1-a]isoindolone derivatives prepared by a palladium-catalysed cascade reaction
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A new family of heterocyclic pentacyclic compounds have been prepared by a cascade reaction involving 2,5-dihalopyridines and (2-formylphenyl)boronic acids. Most of the compounds exhibit high quantum yields of fluorescence in dichloromethane. In some cases, small changes in the substitution pattern caused fluorescence quenching. To rationalize this effect, a detailed photophysical study combined with electrochemical and computational studies was performed on four representative derivatives. It appears that the fluorescence quenching is caused by a thermally activated non-radiative deactivation process that can be prevented in a rigid matrix such as ethanol at 77 K or a PMMA polymer.
- El Abidine Chamas, Zein,Marchi, Enrico,Modelli, Alberto,Fort, Yves,Ceroni, Paola,Mamane, Victor
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p. 2316 - 2324
(2013/05/09)
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- Efficient hydrolysis of organotrifluoroborates via silica gel and water
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(Chemical Equation Presented) A general, mild, and efficient method for the hydrolysis of organotrifluoroborates to unveil boronic acids using silica gel and H2O was developed. This method proved to be tolerant of a broad range of aryl-, heteroaryl-, alkenyl-, and alkyltrifluoroborates as well as structurally diverse aminomethylated organotrifluoroborates.As anticipated, electron-rich substrates provided the corresponding boronic acids more readily than electron-poor substrates, owing to the resonance-stabilized difluoroborane intermediate. The method developed was expanded further for the conversion of organotrifluoroborates to the corresponding boronate esters. 2009 American Chemical Society.
- Molander, Gary A.,Cavalcanti, Livia N.,Canturk, Belgin,Pan, Po-Shen,Kennedy, Lauren E.
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supporting information; experimental part
p. 7364 - 7369
(2010/01/16)
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- Deprotection of pinacolyl boronate esters via hydrolysis of intermediate potassium trifluoroborates
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An efficient two-step procedure for the deprotection of pinacolyl organoboronate esters is described. Reaction with excess potassium hydrogen fluoride produces the corresponding stable, crystalline potassium organotrifluoroborate salts. Treatment of the trifluoroborates with either inorganic base or trimethylsilyl chloride and water affords the corresponding organoboronic acid in high yield.
- Yuen, Alexander K.L.,Hutton, Craig A.
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p. 7899 - 7903
(2007/10/03)
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- Method for producing formylphenylboronic acids
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A process for preparing formylphenylboronic acids of the formula (I) by reaction of protected chlorobenzaldehydes of the formula (II) with lithium in an inert solvent to form compounds of the formula (III) and subsequent reaction with a boron compound of the formula BY3 to give compounds of the formula (I).
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- Preparation, properties, and synthetic potentials of novel boronates in a fluorous version (fluorous boronates)
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(equation presented) 4a-j R = aryl, alkenyl, alkyl A series of boronic acids were attached to a fluorous tag by esterification. Functional transformations of these boronates together with the fluorous Suzuki coupling reaction illustrated their usefulness in fluorous-phase techniques.
- Chen, Dajun,Qing, Feng-Ling,Huang, Yangen
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p. 1003 - 1005
(2007/10/03)
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- Propanoic acid derivatives
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Propanoic acid derivatives of formula (1) are described: Ar—X1—Ar1—Z—R??(1) in which Ar is a nitrogen base containing group; X1is linker atom or group; Ar1is an optionally substituted 5- or 6-membered nitrogen-containing aromatic or non-aromatic monocycle; Z is a group —CH(R13)CH2— [in which R13is an optionally substituted aliphatic, cycloaliphatic, heteroaliphatic, heterocycloaliphatic, aromatic or heteroaromatic group], —C(R12a)(R13)—CH(R12b)— [in which R12aand R12btogether with the carbon atoms to which they are attached form a C3-7cycloalkyl group] or C(R13)═CH—; R is a carboxylic acid (—CO2H) or a derivative or biostere thereof; and the salts, solvates, hydrates and N-oxides thereof. The compounds are able to inhibit the binding of αVintegrins to their ligands and are of use in the prophylaxis and treatment of immune or inflammatory disorders.
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- Planar boron heterocycles with nucleic acid-like hydrogen-bonding motifs
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To promote the development of boron-containing purine analogues that exist in planar, non-zwitterionic dominant structural form. in aqueous solution, rigorous solution and solid state structural analyses of 1-hydroxy-1H-2,3,1-benzoxazaborine (1), 1,2-dihydro-1-hydroxy-2,3,1-benzodiazabo (2), and related 2,3,1-benzodiheteraborines were undertaken. With the aid of isotope-enriched compounds, a multisolvent 1H, 13C, 11B, and 15N NMR spectroscopic analysis of 1 and 2 was conducted, providing structurally-diagnostic chemical shift data for all non-oxygen atoms that constitute their heterocyclic peripheries. In addition, single-crystal X-ray diffraction analyses of 1 and 2 were performed. In stark contrast to their 2,4,1 isomeric counterparts, the 2,3,1-benzoxaza- and benzodiazaborines exist in planar structural form in protic solution and in the solid state and display proton dissociative and associative tendencies reflective of the predominant Bronsted, yet still Lewis acidic-capable character of the B-OH group together with the basic one at the C4-N3 imine group. In the solid state, 1 and 2 display intermolecular hydrogen-bonding patterns not too dissimilar from the motifs of certain natural nucleic acid bases. Diazaborine 2 was shown by VT-NMR to undergo a triple hydrogen-bonding solution association with a 2',3',5'-tri-O-protected cytidine in a demonstration of one biomimetic potential held by a 1-hydroxy-2,3,1-diheteraborine periphery. In general, 1, 2, and related 1-hydroxy-2,3,1-benzodiheteraborine heterocycles were found to be characterized by an environment-dependent O1 → N3 Bronsted prototropy and B-OH group Bronsted/Lewis acid ambidency so sensitive and subtle that certain past difficulties encountered in attempts to delineate their physicochemical properties now become readily appreciated.
- Groziak, Michael P.,Chen, Liya,Yi, Lin,Robinson, Paul D.
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p. 7817 - 7826
(2007/10/03)
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- Synthesis and X-ray crystal structure investigation of a potential boronate affinity chromatography ligand o-boronobenzalmethoxyamine
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A potential boronate affinity chromatography ligand o-boronobenzalmethoxyamine (IV) and its precursor of the distinguishing functional group.In addition, 11B NMR data confirmed the lack of any coordination between the boron and oxygen atoms in the boronic acid compounds III and IV and the catachol ester derivative (V) of IV. o-Formylbenzeneboronic acid (III) crystallizes in space group P21/n with a = 3.883(1), b = 13.225(1), c = 14.029(2) Angstroem, β = 92.16(1) deg, and four molecules per unit cell. o-Boronobenzalmethoxyamine (IV) crystallizes in space group Pccn with a = 14.158(2), b = 17.156(1), c = 7.734(2) Angstroem, and eight molecules per unit cell.Selected bond distances and angles are tabularized.KEY WORDS: Boronate, o-Boronobenzalmethoxyamine, o-formylbenzeneboronic acid(III).
- Scouten, W. H.,Liu, X.-C.,Khangin, N.,Mullica, D. F.,Sappenfield, E. L.
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p. 621 - 626
(2007/10/02)
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