- 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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- 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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- 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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p. 7709 - 7712
(2021/08/09)
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- The First Kilogram Synthesis of Beclabuvir, an HCV NS5B Polymerase Inhibitor
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The process development and kilogram-scale synthesis of beclabuvir (BMS-791325, 1) is described. The convergent synthesis features the use of asymmetric catalysis to generate a chiral cyclopropane fragment and coupling with an indole fragment via an alkyl
- Bien, Jeffrey,Davulcu, Akin,Delmonte, Albert J.,Fraunhoffer, Kenneth J.,Gao, Zhinong,Hang, Chao,Hsiao, Yi,Hu, Wenhao,Katipally, Kishta,Littke, Adam,Pedro, Aghogho,Qiu, Yuping,Sandoval, Maria,Schild, Richard,Soltani, Michelle,Tedesco, Anthony,Vanyo, Dale,Vemishetti, Purushotham,Waltermire, Robert E.
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p. 1393 - 1408
(2018/09/06)
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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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- Internal Lewis acid assisted benzoic acid catalysis
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Internal Lewis acid assisted benzoic acid derivatives are introduced as new low-molecular-weight single-hydrogen-bond donor catalysts for the activation of nitroalkenes. Selected 2-borylbenzoic acid derivatives gave good yields of products in the addition of indoles to nitroalkenes. Control experiments suggest that both the internal Lewis acid coordination and the carboxylic acid functionalities are critical to the optimal performance of these catalysts. Georg Thieme Verlag Stuttgart New York.
- Auvil, Tyler J.,Mattson, Anita E.
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supporting information; experimental part
p. 2173 - 2180
(2012/09/22)
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- Total synthesis of plagiochin D by an intramolecular SNAr reaction
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The total synthesis of plagiochin D, a macrocyclic bis(bibenzyl) compound isolated from the liverwort plagiochila acanthophylla, has been accomplished. Closure of the key 16-membered ring, which contained biphenyl ether and biaryl units, was achieved in good yield by an intramolecular SNAr reaction. The Suzuki and Wittig protocols proved to be powerful tools for the construction of a linear precursor that was crucial for ring cyclization. Copyright
- Cortes Morales, Julio Cesar,Guillen Torres, Alejandro,Gonzalez-Zamora, Eduardo
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scheme or table
p. 3165 - 3170
(2011/06/28)
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- Syntheses of macrocyclic bis(bibenzyl) compounds derived from perrottetin e
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Macrocyclic bis(bibenzyl) compounds are natural products from liverworts and are of growing interest due to recent reports on new isolated compounds and on their remarkable biological activities. We report here on a flexible and general approach to the to
- Speicher, Andreas,Groh, Matthias,Hennrich, Markus,Huynh, Anh-Minh
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p. 6760 - 6778
(2011/03/18)
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- A synthesis-driven structure revision of 'plagiochin E', a highly bioactive bisbibenzyl
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Recently, a bisbibenzyl named plagiochin E showing remarkable antifungal and antitumor activities was isolated from Marchantia polymorpha, a liverwort. The total synthesis of the proposed structure for plagiochin E and of two structurally and biosynthetic
- Speicher, Andreas,Groh, Matthias,Zapp, Josef,Schauml?ffel, Anu,Knauer, Michael,Bringmann, Gerhard
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scheme or table
p. 1852 - 1858
(2009/12/05)
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- Synthesis of a highly soluble superstructured phenanthroline strapped porphyrin
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A highly soluble phenanthroline strapped porphyrin is prepared on multigram scale by appropriate functionalization with C12 chains a posteriori to the efficient cyclization of the tetrapyrrolic macrocycle. A highly soluble phenanthroline strapp
- Koepf, Matthieu,Melin, Frédéric,Jaillard, Jér?me,Weiss, Jean
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p. 139 - 142
(2007/10/03)
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- Rhodium-catalyzed tandem cyclization: Formation of 1H-indenes and 1-alkylideneindans from arylboronate esters in aqueous media
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Arylboronate esters bearing a pendant Michael-type acceptor olefin or acetylene linkage undergo transmetalation with a rhodium-based catalytic complex to generate a functionalized organorhodium intermediate which can cyclize onto nonterminal acetylenes in
- Lautens, Mark,Marquardt, Tzvetelina
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p. 4607 - 4614
(2007/10/03)
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- Synthesis of trans-3,4-dihydroxy-3,4-dihydrophenanthro[3,2-b]-[1]benzothiophene, A potentially carcinogenic metabolite of sulfur heterocycle phenanthro[3,2-b][1]benzothiophene
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The present study describes the synthesis of trans-3,4-dihydroxy-3,4-dihydrophenanthro[3,2-b][1]benzothiophene (3), which is a potential proximate carcinogen of the environmentally occurring potent carcinogen phenanthro-[3,2-b][1]benzothiophene (1). Three approaches were investigated for the synthesis of 3. In the first approach, the diarylalkene 9, which was prepared by the Wittig reaction of ylide 7 and aldehyde 8, was subjected to an oxidative photocyclization reaction to produce a mixture of compounds from which 5, a synthetic precursor to 3, was obtained only in trace amounts. The major cyclized product was 10. The second approach entailed the Suzuki cross-coupling reaction of 2-(dihydroxyboryl)-5-methoxybenzaldehyde (12) with 3-bromodibenzothiophene (11) to produce 13 in 92% yield. The aldehyde function of 13 was elongated with trimethylsulfonium iodide in the presence of KOH to generate the ethylene oxide 14, which, after methanesulfonic acid treatment, produced a 1 : 1 mixture of 3-methoxyphenanthro[3,2-b][1]benzothiophene (6) and 3-methoxyphenanthro[1,2-b][1]benzothiophene (15). Only the undesired compound 15 could be isolated in pure form by extracting the mixture with hot ethanol, leaving behind a 7 : 3 mixture of 6 and 15. In the third approach, the Wittig reaction of 7 with 2-bromo-5-methoxybenzaldehyde (16) produced 17 predominantly as the Z-isomer in quantitative yield. Cyclodehydrobromination of 17 with KOH-quinoline at elevated temperature produced a mixture from which 6 and 3-methoxyphenanthro[3,4-b][1]benzothiophene (18) were easily separated by column chromatography in 23 and 51% yields, respectively. The intermediate 6 was conveniently processed to 3 following the reaction sequence: methoxy phenol→o-quinone→dihydrodiol. A relatively polar dihydrodiol obtained by similar processing of the mixture of 6 and 15 was identified as 3.
- Kumar, Subodh
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p. 1018 - 1023
(2007/10/03)
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