- Synthesis and Antimicrobial Evaluation of New Pyrrolo-isoxazolidine Derivatives
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In the present study, pyrrolo-isoxazolidines 3(a-l) and 4(a-e), 4g, 4i, 4j have been synthesized by using the 1,3-dipolar cycloaddition reactions of nitrones 1(a-l) with ester substituted N-aryl maleimide (2b). These heterocycles have been obtained in cis and trans diastereomeric forms. The structures of newly synthesized heterocycles have been confirmed from their spectroscopic parameters such as IR,1H NMR,13C NMR and ESI-MS. The in vitro antimicrobial evaluation of these compounds were also investigated. Most of the prepared heterocycles showed significant antimicrobial properties. C3-phenyl substituted products exhibited the remarkable antibacterial behaviours while C3-thienyl/furyl substituted heterocycles proved themselves potent antifungal agents.
- Yusuf, Mohamad,Shehneela,Singh, Baldev
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p. 220 - 228
(2018/12/11)
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- Trifluoromethyl Vinyl Sulfide: A Building Block for the Synthesis of CF3S-Containing Isoxazolidines
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Trifluoromethyl vinyl sulfide, a potential building block for pharmaceutically and agrochemically relevant products, is prepared and used for the first time in high-pressure-mediated 1,3-dipolar cycloaddition reactions with nitrones to synthesize (trifluoromethyl)sulfanyl isoxazolidines.
- Riesco-Domínguez, Alejandra,Van De Wiel, Jeroen,Hamlin, Trevor A.,Van Beek, Bas,Lindell, Stephen D.,Blanco-Ania, Daniel,Bickelhaupt, F. Matthias,Rutjes, Floris P. J. T.
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p. 1779 - 1789
(2018/02/23)
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- Metal-free approach for the ?-proline mediated synthesis of nitrones from nitrosobenzene
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An efficient, and metal-free approach for the ?-proline mediated synthesis of nitrones from nitrosobenzene and benzaldehydes has been established. The reaction undergoes very efficiently at room temperature in methanol as a solvent. The reaction is assumed to involve that the initial formation of azomethine ylide and [2 + 3] cycloaddition of nitrosobenzene, followed by the subsequent retro [2 + 3] cycloaddition could offer the desired nitrone.
- Choi, Minho,Viji, Mayavan,Kim, Donghwan,Lee, Young Hee,Sim, Jaeuk,Kwak, Young-Shin,Lee, Kiho,Lee, Heesoon,Jung, Jae-Kyung
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p. 4182 - 4187
(2018/06/19)
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- Chiral: N, N ′-dioxide/Co(II)-promoted asymmetric 1,3-dipolar cycloaddition of nitrones with methyleneindolinones
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A chiral N,N′-dioxide/Co(BF4)2·6H2O complex catalytic system has been developed to efficiently catalyze the asymmetric 1,3-dipolar cycloaddition of nitrones with methyleneindolinones. The corresponding chiral multisubstituted spiroisoxazolidines with three contiguous quaternary-tertiary stereocenters were obtained in moderate to high yields with excellent dr and ee values (up to 97% yield, >19:1 dr and 98% ee).
- Zhang, Dong,Yin, Chengkai,Zhou, Yuhang,Xu, Yali,Lin, Lili,Liu, Xiaohua,Feng, Xiaoming
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supporting information
p. 7925 - 7928
(2017/07/22)
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- Synthesis of 2,3-Disubstituted NH Indoles via Rhodium(III)-Catalyzed C-H Activation of Arylnitrones and Coupling with Diazo Compounds
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A rhodium-catalyzed intermolecular coupling between arylnitrones and diazo compounds by C-H activation/[4 + 1] annulation with a C(N2)-C(acyl) bond cleavage is reported, and 2,3-disubstituted NH indoles are directly synthesized in up to a 94% yield. A variety of functional groups are applicable to this reaction to give the corresponding products with high selectivity. Compared to other previously reported Rh(III)-catalyzed synthesis of homologous series, this method is simpler, more general, and more efficient.
- Guo, Xin,Han, Jianwei,Liu, Yafeng,Qin, Mingda,Zhang, Xueguo,Chen, Baohua
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p. 11505 - 11511
(2017/11/10)
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- Cu(II)-catalyzed enantioselective 1,3-dipolar cycloaddition of nitrones with α, β-unsaturated acyl phosphonates
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A highly enantioselective 1, 3-dipolar cycloaddition of nitrone with α, β-unsaturated acyl phosphonate was developed for the first time by using a chiral indane-bis(oxazoline)-copper(II) complex. The reaction proceeded smoothly under mild conditions to provide isoxazolidines with multi-stereocenters in good yields with high to excellent diastereo- (>20:1 dr) and enantioselectivities (up to 99% ee). The resulting products were readily converted to multi-functional isoxazolidines or γ-amino alcohol compounds.
- Xie, Lei,Bai, Hui,Li, Jiaqi,Yu, Xuan,Zhang, Zhenhua,Fu, Bin
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supporting information
p. 2923 - 2930
(2017/04/27)
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- Iron-Catalyzed Cyclization of Nitrones with Geminal-Substituted Vinyl Acetates: A Direct [4 + 2] Assembly Strategy Leading to 2,4-Disubstituted Quinolines
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An iron-catalyzed intermolecular [4 + 2] cyclization of arylnitrones with geminal-substituted vinyl acetates was developed for the synthesis of 2,4-disubstituted quinolines in moderate to good yields with good functional group compatibilities. Preliminary mechanistic studies suggest a plausible iron-catalyzed C-H activation process under external-oxidant-free conditions.
- Zhong, Mingbing,Sun, Song,Cheng, Jiang,Shao, Ying
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p. 10825 - 10831
(2016/11/29)
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- Design, synthesis and characterization of dual inhibitors against new targets FabG4 and HtdX of Mycobacterium tuberculosis
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Herein, we present dual inhibitors of new targets FabG4 and HtdX for the first time. In this work, eight compounds have been designed, synthesized, characterized and evaluated for bio-activities. Amongst them, six compounds have shown inhibitory activities. Three of them (12e14) demonstrate dual inhibition of both FabG4 and HtdX at low micromolar concentration. In addition, the dual inhibitors show good anti-mycobacterial properties against both planktonic growth and biofilm culture of Mycobacterium species. This study is an important addition to tuberculosis drug discovery because it explores two new enzymes as drug targets and presents their dual inhibitors as good candidates for pre-clinical trials.
- Banerjee, Deb Ranjan,Biswas, Rupam,Das, Amit K.,Basak, Amit
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p. 223 - 234
(2015/06/25)
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- Rhodium-Catalyzed C-H Annulation of Nitrones with Alkynes: A Regiospecific Route to Unsymmetrical 2,3-Diaryl-Substituted Indoles
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The direct C-H annulation of anilines or related compounds with internal alkynes provides straightforward access to 2,3-disubstituted indole products. However, this transformation proceeds with poor regioselectivity in the synthesis of unsymmetrically 2,3-diaryl substituted indoles. Herein, we report the rhodium(III)-catalyzed C-H annulation of nitrones with symmetrical diaryl alkynes as an alternative method to prepare 2,3-diaryl-substituted N-unprotected indoles with two different aryl groups. One of the aryl substituents is derived from N?C-aryl ring of the nitrone and the other from the alkyne substrate, thus providing the indole products with exclusive regioselectivity.
- Yan, Hao,Wang, Haolong,Li, Xincheng,Xin, Xiaoyi,Wang, Chunxiang,Wan, Boshun
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supporting information
p. 10613 - 10617
(2015/09/02)
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- Selective reductive coupling of nitro compounds with aldehydes to nitrones in H2 using carbon-supported and -decorated platinum nanoparticles
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Nitrones were synthesized in high yields directly from nitro compounds, aldehydes, and H2 using carbon-decorated platinum nanoparticles. The high selectivity for nitrone synthesis contrasts that of common supported metal catalysts and correspon
- Cisneros, Larisha,Serna, Pedro,Corma, Avelino
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supporting information
p. 9306 - 9310,5
(2014/10/15)
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- Gold-catalyzed cyclization-cycloaddition cascade reactions of allenyl acetals with nitrones
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Gold and silver: When allenyl acetals and nitrones are treated with a catalytic amount of a gold complex and a silver salt they react through a cyclization-cycloaddition cascade reaction to give a mixture of diastereomeric tricyclic products. The mixture converges to a single product upon acid hydrolysis (see scheme). The key intermediate is postulated to be a 1-methoxyfulvene species. Copyright
- Vasu, Dhananjayan,Liu, Rai-Shung
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supporting information
p. 13638 - 13641
(2013/01/15)
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- Exploiting microwave-assisted neat procedures: synthesis of N-aryl and N-alkylnitrones and their cycloaddition en route for isoxazolidines
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Microwave irradiation allows increasing the speed of several reactions and also offers the possibility of eliminating poisoning organic solvents. In this work we report the microwave-assisted neat synthesis of α-phenyl-tert-butylnitrone (PBN) and other alkyl and aryl nitrones and also the rapid synthesis of isoxazolidines resulting from 1,3-dipolar cycloaddition of nitrones to ethyl trans-crotonate.
- Andrade, Marta M.,Barros, Maria Teresa,Pinto, Rui C.
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p. 10521 - 10530
(2008/12/23)
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- α-(trifluoromethyl)amine derivatives via nucleophilic trifluoromethylation of nitrones
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(Trifluoromethyl)trimethylsilane (TMSCF3) reacts with nitrones to afford α-(trifluoromethyl)hydroxylamines protected as O-trimethylsilyl ethers. Potassium t-butoxide initiates the nucleophilic trifluoromethylation. The reaction works best with α,N-diaryl nitrones, and the conditions are compatible with a range of substituents on the aryl groups. Acidic deprotection of the nitrone/TMSCF3 adducts generates α-(trifluoromethyl)hydroxylamines. Catalytic hydrogenation of the adducts produces α-(trifluoromethyl)amines. Nitrone/TMSCF3 adducts with strong electron-withdrawing groups on the α-aryl ring or heterocyclic α-aryl groups undergo an elimination/addition sequence to generate α, α-bis(trifluoromethyl)amines. Nitrones with alkyl groups bound directly to the 1,3-dipolar moiety fail to react with TMSCF3, but trifluoromethylation of β,γ-unsaturated nitrones followed by reduction of the double bond can circumvent this limitation.
- Nelson,Owens,Hiraldo
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p. 2572 - 2582
(2007/10/03)
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- A clean clay catalysed synthesis of α,N-diarylnitrones
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The first clean and the facile clay catalysed synthesis of α,N-diarylnitrones in good yield is reported.
- Venkatachalapathy, Chockalingam,Thirumalaikumar, Muniappan,Muthusubramanian, Shanmugam,Pitchumani, Kasi,Sivasubramanian, Shunmugaperumal
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p. 4041 - 4047
(2007/10/03)
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- Reaction of Aldonitrones with Copper Acetylide : Synthesis of Some Novel β-Lactams
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Nitrones (7a-e) react with copper acetylide (6) to afford cis- and trans-β-lactams (8 and 9) in good yields.The cis- and trans-isomers have been isolated, respectively as the major and minor products and are characterized through spectral data (IR, mass a
- Dutta, D. K.,Boruah, R. C.,Sandhu, J. S.
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p. 350 - 353
(2007/10/02)
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