- Exploiting the chiral ligands of bis(Imidazolinyl)-and bis(oxazolinyl)thiophenes—Synthesis and application in Cu-catalyzed friedel–crafts asymmetric alkylation
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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.
- Al-Majid, Abdullah Mohammed,Alammari, Abdullah Saleh,Alshahrani, Saeed,Barakat, Assem,Haukka, Matti,Islam, Mohammad Shahidul
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- Tryptamine derivatives disarm colistin resistance in polymyxin-resistant gram-negative bacteria
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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.
- Barker, William T.,Chandler, Courtney E.,Melander, Roberta J.,Ernst, Robert K.,Melander, Christian
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p. 1776 - 1788
(2019/03/21)
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- 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
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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
- Liu, Jiaxin,Li, Longhai,Yu, Liuzhu,Tang, Lisha,Chen, Qin,Shi, Min
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supporting information
p. 2959 - 2965
(2018/08/17)
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- Green synthesis of new pyrrolidine-fused spirooxindoles: Via three-component domino reaction in EtOH/H2O
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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.
- Wang, Yong-Chao,Wang, Jun-Liang,Burgess, Kevin S.,Zhang, Jiang-Wei,Zheng, Qiu-Mei,Pu, Ya-Dan,Yan, Li-Jun,Chen, Xue-Bing
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p. 5702 - 5713
(2018/02/14)
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- Organocatalytic enantioselective synthesis of C3 functionalized indole derivatives
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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.
- Kaur, Jasneet,Islam, Nasarul,Kumar, Akshay,Bhardwaj, Vimal K.,Chimni, Swapandeep Singh
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p. 8042 - 8049
(2016/11/22)
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- Green synthesis of nitroenamines by γ-Fe2O3@SiO2-OSO3H nanoparticles as a highly efficient and magnetically separable catalyst
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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
- Mahdudi, Samaneh,Saberi, Dariush,Heydari, Akbar
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p. 903 - 907
(2015/03/18)
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- Asymmetric dearomatization of indoles through a Michael/Friedel-Crafts-Type cascade to construct polycyclic spiroindolines
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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.
- Zhao, Xiaohu,Liu, Xiaohua,Mei, Hongjiang,Guo, Jing,Lin, Lili,Feng, Xiaoming
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supporting information
p. 4032 - 4035
(2015/03/30)
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- Organocatalytic asymmetric Michael addition of aliphatic aldehydes to indolylnitroalkenes: Access to contiguous stereogenic tryptamine precursors
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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.
- Chen, Jian,Geng, Zhi-Cong,Li, Ning,Huang, Xiao-Fei,Pan, Feng-Feng,Wang, Xing-Wang
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p. 2362 - 2372
(2013/05/21)
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- 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
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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
- Jalal, Swapnadeep,Sarkar, Soumen,Bera, Krishnendu,Maiti, Sukhendu,Jana, Umasish
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supporting information
p. 4823 - 4828
(2013/08/23)
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- Rhodium-catalyzed asymmetric addition of arylboronic acids to indolylnitroalkenes
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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.
- Xing, Junwei,Chen, Guihua,Cao, Peng,Liao, Jian
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supporting information; experimental part
p. 1230 - 1236
(2012/04/10)
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- Straightforward synthesis of nitroolefins by microwave- or ultrasound-assisted Henry reaction
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β-Nitroalcohol or nitroethylene derivatives can be obtained from aryl aldehydes and nitromethane under Henry condensation conditions. We present a new modification using microwave irradiation or ultrasound as the energy source. Microwave irradiation allowed a novel one-pot synthesis of nitroolefins from aryl aldehydes using ammonium acetate as a catalyst without solvent. Different reaction conditions, such as base, solvent, and reaction time were studied. Only small amounts of β-hydroxyl nitro compounds were isolated, using microwave irradiation for less than 25 min. In contrast, the use of ultrasound increased the yield of the nitroalcohols.
- Rodríguez, Jose M.,Dolors Pujol
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scheme or table
p. 2629 - 2632
(2011/06/10)
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- Synthesis of vinylphosphonates and its first exploration of bioactivity
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Phosphonation of β-nitro-alkene with triethyl phosphite was achieved under microwave irradiation using CH2Cl2 as the solvent in the absence of catalyst with moderate to high yields (up to 90%). This method of formation of carbonphosphor bonds is simple, mild, convenient and effective. Synchronously, a number of vinylphosphonates derivatives were synthesized and evaluated biologically preliminary.
- Li, Sheng-Nan,Xu, Lan-Ting,Chenb, Yue,Lia, Ju-Lian,He, Ling
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experimental part
p. 416 - 422
(2012/05/04)
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- Synthesis of 2-and 3-indolylpyrroles via 1,3-dipolar cycloadditions of muenchnones and nitroalkenes
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A series of 2-and 3-indolylpyrroles were generated via 1,3-dipolar cycloadditions between (2-nitrovinyl)indoles and symmetrical and unsymmetrical 1,3-oxazolium-5-olates (muenchnones). The Japan Institute of Heterocyclic Chemistry.
- Lopchuk, Justin M.,Gribble, Gordon W.
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experimental part
p. 1617 - 1631
(2011/05/04)
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- Efficient one-pot synthesis of anti-HIV and anti-tumour β-carbolines
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Thermal electrocyclisation of the azahexatriene system has been used as a key step for the synthesis of anti-HIV and anti-tumour compounds, harman, derivatives of harman and 1-aryl-β-carbolines. A one-pot reaction sequence was used to furnish these compounds in good yield.
- Kusurkar, Radhika S.,Goswami, Shailesh K.
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p. 5315 - 5318
(2007/10/03)
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- Efficient one-pot synthesis of anti HIV and antitumor compounds: Harman and substituted harmans
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Anti HIV and antitumor compounds, harman and substituted harmans have been synthesized using electrocyclization reactions as key steps. A one-pot reaction sequence was used to furnish these compounds in good overall yield.
- Kusurkar, Radhika S.,Goswami, Shailesh K.,Vyas, Sandhya M.
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p. 4761 - 4763
(2007/10/03)
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- Novel and potent human and rat β3-adrenergic receptor agonists containing substituted 3-indolylalkylamines
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A novel series of 2-(3-indolyl)alkylamino-1-(3-chlorophenyl)ethanols was prepared and evaluated for in vitro ability to stimulate cAMP production in Chinese hamster ovary cells expressing cloned human β3-AR. The optically active 30a was found to be the most potent and selective human β3-AR agonist in this series with an EC50 value of 0.062 nM. In addition, 30a selectivity for human β3-AR was 210-fold and 103-fold that for human β2-AR and β1-AR, respectively. Furthermore, 30a showed potent agonistic activity at rat β3-AR.
- Harada, Hiroshi,Hirokawa, Yoshimi,Suzuki, Kenji,Hiyama, Yoichi,Oue, Mayumi,Kawashima, Hitoshi,Yoshida, Naoyuki,Furutani, Yasuji,Kato, Shiro
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p. 1301 - 1305
(2007/10/03)
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- Indole derivatives with antimycobacterial activity
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1,3-Dinitro-2-(indol-3'-yl)-propanes 3 are synthesized by Michael reaction of nitromethane with the indolylnitroethenes 2. - Reaction of the aldehydes 4 and 10 with the benzylamines 12 as well as the reaction of the indolylalkylamines 6a and 9a with the benzaldehydes 11 lead to Schiff bases which are reduced to N-benzyl-(indol-3-ylmethyl)-amines 13 and N-benzyl-(indol-3-ylethyl)-amines 14, respectively; tert amines 16 are synthesized via the formamides 15, amines 18 are prepared according to Mannich. - Inhibitory effects on Mycobacterium tuberculosis H 37 Ra are investigated, a structure-activity relationship is discussed.
- Mahboobi,Grothus,Meindl
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p. 105 - 114
(2007/10/02)
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- Nitrones and Oxaziridines. XLVII. Intermolecular Cycloaddition of Fused Indolyl Nitrone Ring Systems
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The two dihydro-β-carboline N-oxides (6) and (18) have been prepared by reductive cyclization of 2-acetyl-3-(β-nitroethyl)indoles.These cyclic nitrones undergo 1,3-dipolar cycloaddition to alkynes to give the cycloadducts (21)-(25).Thermal rearrangement of the adduct (22) gives the indolizinoindole (27) in high yield.The X-ray crystal structure determination of the adduct (24) is reported.
- Black, David St. C.,Craig, Donald C.,Deb-Das, Renu B.,Kumar, Naresh,Wright, Timothy A.
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p. 1725 - 1742
(2007/10/02)
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