2731-00-2Relevant academic research and scientific papers
Exploiting the chiral ligands of bis(Imidazolinyl)-and bis(oxazolinyl)thiophenes—Synthesis and application in Cu-catalyzed friedel–crafts asymmetric alkylation
Al-Majid, Abdullah Mohammed,Alammari, Abdullah Saleh,Alshahrani, Saeed,Barakat, Assem,Haukka, Matti,Islam, Mohammad Shahidul
, (2021/12/17)
Five new C2-symmetric chiral ligands of 2,5-bis(imidazolinyl)thiophene (L1–L3) and 2,5-bis(oxazolinyl)thiophene (L4 and L5) were synthesized from thiophene-2,5-dicarboxylic acid (1) with enantiopure amino alcohols (4a–c) in excellent optical purity and chemical yield. The util-ity of these new chiral ligands for Friedel–Crafts asymmetric alkylation was explored. Subse-quently, the optimized tridentate ligand L5 and Cu(OTf)2 catalyst (15 mol%) in toluene for 48 h promoted Friedel–Crafts asymmetric alkylation in moderate to good yields (up to 76%) and with good enantioselectivity (up to 81% ee). The bis(oxazolinyl)thiophene ligands were more potent than bis(imidazolinyl)thiophene analogues for the asymmetric induction of the Friedel–Crafts asymmetric alkylation.
Tryptamine derivatives disarm colistin resistance in polymyxin-resistant gram-negative bacteria
Barker, William T.,Chandler, Courtney E.,Melander, Roberta J.,Ernst, Robert K.,Melander, Christian
, p. 1776 - 1788 (2019/03/21)
The last three decades have seen a dwindling number of novel antibiotic classes approved for clinical use and a concurrent increase in levels of antibiotic resistance, necessitating alternative methods to combat the rise of multi-drug resistant bacteria. A promising strategy employs antibiotic adjuvants, non-toxic molecules that disarm antibiotic resistance. When co-dosed with antibiotics, these compounds restore antibiotic efficacy in drug-resistant strains. Herein we identify derivatives of tryptamine, a ubiquitous biochemical scaffold containing an indole ring system, capable of disarming colistin resistance in the Gram-negative bacterial pathogens Acinetobacter baumannii, Klebsiella pneumoniae, and Escherichia coli while having no inherent bacterial toxicity. Resistance was overcome in strains carrying endogenous chromosomally-encoded colistin resistance machinery, as well as resistance conferred by the mobile colistin resistance-1 (mcr-1) plasmid-borne gene. These compounds restore a colistin minimum inhibitory concentration (MIC) below the Clinical & Laboratory Sciences Institute (CLSI) breakpoint in all resistant strains.
Green synthesis of new pyrrolidine-fused spirooxindoles: Via three-component domino reaction in EtOH/H2O
Wang, Yong-Chao,Wang, Jun-Liang,Burgess, Kevin S.,Zhang, Jiang-Wei,Zheng, Qiu-Mei,Pu, Ya-Dan,Yan, Li-Jun,Chen, Xue-Bing
, p. 5702 - 5713 (2018/02/14)
An efficient, green and sustainable approach for the synthesis of novel polycyclic pyrrolidine-fused spirooxindole compounds was developed. The synthesis included a one-pot, three-component, domino reaction of (E)-3-(2-nitrovinyl)-indoles, isatins and chiral polycyclic α-amino acids under catalyst-free conditions at room temperature in EtOH-H2O. The salient features of this methodology are eco-friendliness, high yields and the ease of obtaining target compounds without the involvement of toxic solvents and column chromatography. These novel polycyclic pyrrolidine-fused spirooxindoles provide a collection of structurally diverse compounds that show promise for future bioassays and medical treatments.
Visible-Light-Induced Trifluoromethylation of Isonitrile-Substituted Indole Derivatives: Access to 1-(Trifluoromethyl)-4,9-dihydro-3H-pyrido[3,4-b]indole and β-Carboline Derivatives
Liu, Jiaxin,Li, Longhai,Yu, Liuzhu,Tang, Lisha,Chen, Qin,Shi, Min
supporting information, p. 2959 - 2965 (2018/08/17)
A visible-light-induced trifluoromethylation of isonitrile-substituted indole derivatives has been developed from the reaction of isonitrile-substituted indoles with Togni II reagent, affording 1-(trifluoromethyl)-4,9-dihydro-3H-pyrido[3,4-b]indoles in mo
Organocatalytic enantioselective synthesis of C3 functionalized indole derivatives
Kaur, Jasneet,Islam, Nasarul,Kumar, Akshay,Bhardwaj, Vimal K.,Chimni, Swapandeep Singh
, p. 8042 - 8049 (2016/11/22)
A highly enantioselective Michael addition reaction of indolylnitroalkenes with 1,3-dicarbonyl compounds has been developed to obtain enantiomerically enriched 3-(2-nitro-1-(1-tosyl-1H-indol-3-yl)ethyl)pentane-2,4-dione derivatives in up to 98% ee using BnCPN as an organocatalyst. The transition state structure has been predicted using DFT calculation.
Green synthesis of nitroenamines by γ-Fe2O3@SiO2-OSO3H nanoparticles as a highly efficient and magnetically separable catalyst
Mahdudi, Samaneh,Saberi, Dariush,Heydari, Akbar
, p. 903 - 907 (2015/03/18)
Some derivatives of nitroenamines were synthesized in moderate to good yields in the presence of sulfonic acid supported on silica-modified maghemite (γ-Fe2O3@SiO2-OSO3H) as a highly efficient and magnetically s
Asymmetric dearomatization of indoles through a Michael/Friedel-Crafts-Type cascade to construct polycyclic spiroindolines
Zhao, Xiaohu,Liu, Xiaohua,Mei, Hongjiang,Guo, Jing,Lin, Lili,Feng, Xiaoming
supporting information, p. 4032 - 4035 (2015/03/30)
A highly efficient asymmetric dearomatization of indoles was realized through a cascade reaction between 2-isocyanoethylindole and alkylidene malonates catalyzed by a chiral N,N-dioxide/MgII catalyst. Fused polycyclic indolines containing three stereocenters were afforded in good yields with excellent diastereo- and enantioselectivities through a Michael/Friedel-Crafts/Mannich cascade. When 2-substituted 2-isocyanoethylindoles were used, spiroindoline derivatives were obtained through a Michael/Friedel-Crafts reaction.
Synthesis of nitroalkenes involving a cooperative catalytic action of iron(III) and piperidine: A one-pot synthetic strategy to 3-alkylindoles, 2H-chromenes and N-arylpyrrole
Jalal, Swapnadeep,Sarkar, Soumen,Bera, Krishnendu,Maiti, Sukhendu,Jana, Umasish
supporting information, p. 4823 - 4828 (2013/08/23)
An efficient and simple strategy has been developed to synthesize various substituted nitroalkenes involving a cooperative catalytic system of FeCl 3 and piperidine. This dual catalytic protocol simultaneously activates both electrophile and nucleophile and works under mild reaction conditions so that many sensitive functional groups were tolerated. Moreover, this cooperative catalytic reaction is also suitable for various one-pot reactions involving nitroalkenes such as, 2H-chromenes, N-arylpyrrole and Michael reaction with indole. Notably, this method is low-cost, efficient and environmentally friendly. Copyright
Organocatalytic asymmetric Michael addition of aliphatic aldehydes to indolylnitroalkenes: Access to contiguous stereogenic tryptamine precursors
Chen, Jian,Geng, Zhi-Cong,Li, Ning,Huang, Xiao-Fei,Pan, Feng-Feng,Wang, Xing-Wang
, p. 2362 - 2372 (2013/05/21)
Because of the importance of the indole framework and the versatile transformation of nitro and formyl groups, the efficient synthesis of optically pure 2-alkyl-3-(1H-indol-3-yl)-4-nitrobutanals, one type of tryptamine precursors are of great interest for pharmaceutical and biological research. Herein, the Michael addition of aliphatic aldehydes to indolylnitroalkenes has been developed using (S)-diphenylprolinol trimethylsilyl ether as an organocatalyst, which provides the desired optically pure syn 2-alkyl-3-(1H-indol-3-yl)-4-nitrobutanal derivatives in up to 98% yield with up to >99:1 dr and >99% ee. To show the synthetic usefulness of this methodology, optically active 2-alkyl-4-nitro-3-(1-tosyl-1H-indol-3-yl)butan-1- ol and tryptamine derivatives are readily obtained by stepwise systematic transformations.
Rhodium-catalyzed asymmetric addition of arylboronic acids to indolylnitroalkenes
Xing, Junwei,Chen, Guihua,Cao, Peng,Liao, Jian
supporting information; experimental part, p. 1230 - 1236 (2012/04/10)
Indolylnitroethanes and their derivatives are key intermediates to many bioactive structures. Most approaches to access chiral indolylnitroethanes involve organocatalyzed or metal-catalyzed asymmetric Friedel-Crafts reaction of indoles with nitroalkenes.
