- Transient imine as a directing group for the metal-free o-C-H borylation of benzaldehydes
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Organoboron reagents are important synthetic intermediates and have wide applications in synthetic organic chemistry. The selective borylation strategies that are currently in use largely rely on the use of transition-metal catalysts. Hence, identifying much milder conditions for transition-metal-free borylation would be highly desirable. We herein present a unified strategy for the selective C-H borylation of electron-deficient benzaldehyde derivatives using a simple metal-free approach, utilizing an imine transient directing group. The strategy covers a wide spectrum of reactions and (i) even highly sterically hindered C-H bonds can be borylated smoothly, (ii) despite the presence of other potential directing groups, the reaction selectively occurs at the o-C-H bond of the benzaldehyde moiety, and (iii) natural products appended to benzaldehyde derivatives can also give the appropriate borylated products. Moreover, the efficacy of the protocol was confirmed by the fact that the reaction proceeds even in the presence of a series of external impurities.
- Rej, Supriya,Chatani, Naoto
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supporting information
p. 2920 - 2929
(2021/03/01)
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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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- Transition-metal-free, one-pot synthesis of benzoxaboroles from: O -bromobenzaldehydes via visible-light-promoted borylation
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A novel and simple one-pot stepwise method to synthesize benzoxaboroles was demonstrated. This step-by-step synthetic method includes photocatalytic boronization with phenothiazine as a photocatalyst and sequential water-induced reduction in the presence of bis(pinacolato)diboron. A series of o-bromobenzaldehydes were well-tolerated under the standard conditions. In addition, this method has been successfully applied in the synthesis of the anti-tuberculosis candidate drug GSK 3036656 and anti-fungal drug tavaborole. This journal is
- Chen, Jianchao,Hu, Yanjun,Jia, Xingxing,Luo, Jinghan,Sun, Tiemin
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p. 10455 - 10459
(2021/12/17)
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- Preparation process of antifungal drug tavaborole
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The invention relates to a preparation process of an antifungal drug tavaborole. The preparation process of the antifungal drug tavaborole comprises the following reaction steps: taking 2-bromo-5-fluorobenzaldehyde as a starting material, reacting the 2-bromo-5-fluorobenzaldehyde with pinacol borate in the presence of a palladium catalyst and a solvent to generate 2-pinacol boron-5-fluorobenzaldehyde (TAV-A), and carrying out reduction and ring closure to generate the product tavaborole. In aftertreatment, the PH value of a reaction solution is adjusted by using sig water, and then the tavaborole can be separated out. The preparation process is short in reaction steps, mild and safe in conditions, easy to operate and high in yield, is environmentally friendly, and is suitable for industrial production.
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Paragraph 0020-0025
(2019/04/06)
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- 1-HYDROXY-1,3-DIHYDROBENZO[c][1,2]OXABOROLES AND THEIR USE AS HERBICIDES
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Provided herein are 1-hydroxy-1,3-dihydrobenzo[c][1,2]oxaboroles and their derivatives, and compositions and methods of use thereof as herbicides.
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Page/Page column 30
(2018/09/19)
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- Imidazole-containing condensed tricyclic compound and application thereof
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The invention discloses an imidazole-containing condensed tricyclic compound adopting the structure as shown in the formula (I) or pharmaceutically acceptable salts, stereisomers or prodrug molecules thereof. The imidazole-containing condensed tricyclic compound has the IDO1 activity regulation function, can enhance T-cell activation through blocking immune checkpoints IDO1, is used for treating IDO1-mediated immunosuppression, and therefore, can become an effective medicine for treating malignant tumors. When used together with checkpoint protein anti-body drugs or other anti-cancer drugs, the imidazole-containing condensed tricyclic compound can enhance the anti-cancer effect. Meanwhile, the imidazole-containing condensed tricyclic compound has the potential of effectively treating IDO1 abnormity related immunosuppressive diseases and has a high application value.
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Paragraph 0198
(2018/03/01)
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- Copper-Catalyzed Annulation: A Method for the Systematic Synthesis of Phenanthridinium Bromide
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A novel procedure for the Cu-catalyzed systematic synthesis of phenanthridinium bromide is reported. This transformation was achieved with direct construction of central pyridinium core by using an in situ formed biaryl imine as a substrate. Tolerance of a very wide variety of N-substituents is indicated; this has never previously been disclosed by other reports. Application of this method to synthesis of the natural alkaloid bicolorine, and its derivatives, was also carried out in only three synthetic steps from commercially available compounds.
- Jhang, Yuan-Ye,Fan-Chiang, Tai-Ting,Huang, Jun-Min,Hsieh, Jen-Chieh
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supporting information
p. 1154 - 1157
(2016/03/15)
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- Formal Ir-Catalyzed Ligand-Enabled Ortho and Meta Borylation of Aromatic Aldehydes via in Situ-Generated Imines
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The ligand-enabled development of ortho and meta C-H borylation of aromatic aldehydes is reported. It was envisaged that while ortho borylation could be achieved using tert-butylamine as the traceless protecting/directing group, meta borylation proceeds via an electrostatic interaction and a secondary interaction between the ligand of the catalyst and the substrate. These ligand-substrate electrostatic interactions and secondary B-N interactions provide an unprecedented controlling factor for meta-selective C-H activation/borylation.
- Bisht, Ranjana,Chattopadhyay, Buddhadeb
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