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Current Organocatalysis

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ISSN (Print): 2213-3372
ISSN (Online): 2213-3380

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Research Article

Choline Chloride/Glycerol Promoted Synthesis of 3,3-Disubstituted Indol- 2-ones

Author(s): Ling Xu, Wei-Hong Zhang, Zhen-Shui Cui and Zhan-Hui Zhang*

Volume 8, Issue 2, 2021

Published on: 04 January, 2021

Page: [249 - 257] Pages: 9

DOI: 10.2174/2213337207999210104223005

Price: $65

Abstract

Objective: 3,3-Disubstituted indol-2-one derivatives have wider applications in pharmaceuticals and they are key intermediates for the synthesis of many kinds of drug candidates. The development of an efficient and practical method to prepare this class of compound is highly desirable from both environmental and economical points of views.

Methods: In order to establish an effective synthetic method for preparing 3,3-disubstituted indol- 2-one derivatives, the bis-condensation reaction of isatin and 1H-indene-1,3(2H)-dione was selected as a model reaction. A variety of natural deep eutectic solvents (NADESs) were prepared and used for this reaction. The generality and limitation of the established method were also investigated.

Results: It was found that model reaction can be carried out in natural deep eutectic solvent (NADES) based on choline chloride (ChCl) at 80°C under microwave irradiation. This protocol with a broad substrate applicability afforded various 2,2'-(2-oxoindoline-3,3-diyl)bis(1H-indene- 1,3(2H)-dione) derivatives in high yields.

Conclusion: A simple and efficient procedure has been developed for synthesis of 2,2'-(2-oxoindoline- 3,3-diyl)bis(1H-indene-1,3(2H)-dione), spiro[indoline-3,7'-pyrano[5,6-c:5,6-c']dichromene]- 2,6',8'-trione, and spiro[indoline-3,9'-xanthene]trione via bis-condensation between isatin with 1,3- indandione, 4-hydroxycoumarin or 1,3-cyclohexanedione in natural deep eutectic solvent (NADES) based on choline chloride (ChCl) and glycerol (Gl) under microwave irradiation. The salient features of this protocol are avoidance of any additive/catalyst and toxic organic solvent, clean reaction profiles, non-chromatographic purification procedure, and high to excellent yield. Furthermore, the use of NADES as green reaction medium reduces burden on environment and makes the present method environmentally sustainable.

Keywords: Choline chloride/glycerol, 3, 3-disubstituted indol-2-ones, green chemistry, isatin, natural deep eutectic solvent, microwave irradiation.

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[1]
Singh, G.S.; Desta, Z.Y. Isatins as privileged molecules in design and synthesis of spiro-fused cyclic frameworks. Chem. Rev., 2012, 112(11), 6104-6155.
[http://dx.doi.org/10.1021/cr300135y] [PMID: 22950860]
[2]
Guo, H. Isatin derivatives and their anti-bacterial activities. Eur. J. Med. Chem., 2019, 164, 678-688.
[http://dx.doi.org/10.1016/j.ejmech.2018.12.017] [PMID: 30654239]
[3]
Moradi, R.; Ziarani, G.M.; Lashgari, N. Recent applications of isatin in the synthesis of organic compounds. ARKIVOC, 2017, S1, 148-201.
[http://dx.doi.org/10.24820/ark.5550190.p009.980]
[4]
Varun, ; Sonam, ; Kakkar, R. Isatin and its derivatives: a survey of recent syntheses, reactions, and applications. MedChemComm, 2019, 10(3), 351-368.
[http://dx.doi.org/10.1039/C8MD00585K] [PMID: 30996856]
[5]
Liu, Y.Y.; Wang, H.; Wan, J.P. Recent Advances in diversity oriented synthesis through isatin-based multicomponent reactions. Asian J. Org. Chem., 2013, 2, 374-386.
[http://dx.doi.org/10.1002/ajoc.201200180]
[6]
Chen, M.N.; Di, J.Q.; Li, J.M.; Mo, L.P.; Zhang, Z.H. Eosin Y-catalyzed one-pot synthesis of spiro 4H-pyran-oxindole under visible light irradiation. Tetrahedron, 2020, 76, 131059.
[http://dx.doi.org/10.1016/j.tet.2020.131059]
[7]
Deng, J.; Mo, L.P.; Zhao, F.Y.; Zhang, Z.H.; Liu, S.X. One-pot, three-component synthesis of a library of spirooxindole-pyrimidines catalyzed by magnetic nanoparticle supported dodecyl benzenesulfonic acid in aqueous media. ACS Comb. Sci., 2012, 14(5), 335-341.
[http://dx.doi.org/10.1021/co3000264] [PMID: 22533528]
[8]
Guo, R.Y.; An, Z.M.; Mo, L.P.; Yang, S.T.; Liu, H.X.; Wang, S.X.; Zhang, Z.H. Meglumine promoted one-pot, four-component synthesis of pyranopyrazole derivatives. Tetrahedron, 2013, 69, 9931-9938.
[http://dx.doi.org/10.1016/j.tet.2013.09.082]
[9]
Guo, R.Y.; Wang, P.; Wang, G.D.; Mo, L.P.; Zhang, Z.H. One-pot three-component synthesis of functionalized spirooxindoles in gluconic acid aqueous solution. Tetrahedron, 2013, 69, 2056-2061.
[http://dx.doi.org/10.1016/j.tet.2012.12.081]
[10]
Zhang, M.; Chen, M.N.; Li, J.M.; Liu, N.; Zhang, Z.H. Visible- Light-initiated one-pot, three-component synthesis of 2-amino-4H-pyran-3,5-dicarbonitrile derivatives. ACS Comb. Sci., 2019, 21(10), 685-691.
[http://dx.doi.org/10.1021/acscombsci.9b00124] [PMID: 31433619]
[11]
Zhang, M.; Fu, Q.Y.; Gao, G.; He, H.Y.; Zhang, Y.; Wu, Y.S.; Zhang, Z.H. Catalyst-free, visible-light promoted one-pot synthesis of spirooxindole-pyran derivatives in aqueous ethyl lactate. ACS Sustain. Chem. & Eng., 2017, 5, 6175-6182.
[http://dx.doi.org/10.1021/acssuschemeng.7b01102]
[12]
Wu, H.; Ma, N.N.; Song, M.X.; Zhang, G.S. Dimethyl sulfoxide-aided copper(0)-catalyzed intramolecular decarbonylative rearrangement of N-aryl isatins leading to acridones. Chin. Chem. Lett., 2020, 31, 1580-1583.
[http://dx.doi.org/10.1016/j.cclet.2019.10.043]
[13]
Paterna, R.; Andre, V.; Duarte, M.T.; Veiros, L.F.; Candeias, N.R.; Gois, P.M.P. Ring-expansion reaction of isatins with ethyl diazoacetate catalyzed by dirhodium(II)/DBU metal-organic system: en route to viridicatin alkaloids. Eur. J. Org. Chem., 2013, 2013, 6280-6290.
[http://dx.doi.org/10.1002/ejoc.201300796]
[14]
Jiang, S.F.; Xu, C.; Zhou, Z.W.; Zhang, Q.; Wen, X.H.; Jia, F.C.; Wu, A.X. Switchable access to 3-carboxylate-4-quinolones and 1-vinyl-3-carboxylate-4-quinolones via oxidative cyclization of isatins and alkynes. Org. Lett., 2018, 20(14), 4231-4234.
[http://dx.doi.org/10.1021/acs.orglett.8b01645] [PMID: 29953242]
[15]
Jia, F.C.; Xu, C.; Wang, Y.W.; Chen, Z.P.; Chen, Y.F.; Wu, A.X. Copper-catalyzed ambient-temperature decarboxylative annulation of isatins with amidine hydrochlorides: a facile access to 2-(1,3,5-triazin-2-yl)aniline derivatives. Org. Biomol. Chem., 2018, 16(23), 4223-4226.
[http://dx.doi.org/10.1039/C8OB00904J] [PMID: 29790555]
[16]
Wang, C.M.; Xia, P.J.; Xiao, J.A.; Li, J.; Xiang, H.Y.; Chen, X.Q.; Yang, H. Photoredox-catalyzed reductive dimerization of isatins and isatin-derived ketimines: diastereoselective construction of 3,3′-disubstituted bisoxindoles. J. Org. Chem., 2017, 82(7), 3895-3900.
[http://dx.doi.org/10.1021/acs.joc.6b03056] [PMID: 28281753]
[17]
Ding, R.; Bakhshi, P.R.; Wolf, C. Organocatalytic insertion of isatins into aryl difluoronitromethyl ketones. J. Org. Chem., 2017, 82(2), 1273-1278.
[http://dx.doi.org/10.1021/acs.joc.6b02704] [PMID: 28032765]
[18]
Christodoulou, M.S.; Nicoletti, F.; Mangano, K.; Chiacchio, M.A.; Facchetti, G.; Rimoldi, I.; Beccalli, E.M.; Giofrè, S. Novel 3,3-disubstituted oxindole derivatives. Synthesis and evaluation of the anti-proliferative activity. Bioorg. Med. Chem. Lett., 2020, 30(2), 126845.
[http://dx.doi.org/10.1016/j.bmcl.2019.126845] [PMID: 31831381]
[19]
Ghahremanzadeh, R.; Fereshtehnejad, F.; Mirzaei, P.; Bazgir, A. Ultrasound-assisted synthesis of 2,2′-(2-oxoindoline-3,3-diyl)bis(1H-indene-1,3(2H)-dione) derivatives. Ultrason. Sonochem., 2011, 18(1), 415-418.
[http://dx.doi.org/10.1016/j.ultsonch.2010.07.010] [PMID: 20708954]
[20]
Parthasarathy, K.; Praveen, C.; Jeyaveeran, J.C.; Prince, A.A.M. Gold catalyzed double condensation reaction: Synthesis, antimicrobial and cytotoxicity of spirooxindole derivatives. Bioorg. Med. Chem. Lett., 2016, 26(17), 4310-4317.
[http://dx.doi.org/10.1016/j.bmcl.2016.07.036] [PMID: 27476145]
[21]
Gao, L.J.; Zha, Y.Y.; Tao, S.M.; Gao, Y.A.; Chen, M.; Jiang, L.; Rong, L.C.I. 2-Catalyzed three-component procedure for synthesis of substituted spiro[indoline-3,7′-pyrano[3,2-c:5,6-c']dichromene]-2,6′,8′-trione derivatives. Res. Chem. Intermed., 2015, 41, 5627-5634.
[http://dx.doi.org/10.1007/s11164-014-1688-4]
[22]
Khalafi-Nezhad, A.; Shahidzadeh, E.S.; Sarikhani, S.; Panahi, F. A new silica-supported organocatalyst based on L-proline: An efficient heterogeneous catalyst for one-pot synthesis of spiroindolones in water. J. Mol. Catal. A: Chem., 2013, 379, 1-8.
[http://dx.doi.org/10.1016/j.molcata.2013.07.009]
[23]
Kothandapani, J.; Ganesan, A.; Mani, G.K.; Kulandaisamy, A.J.; Rayappan, J.B.B.; Ganesan, S.S. Zinc oxide surface: a versatile nanoplatform for solvent-free synthesis of diverse isatin derivatives. Tetrahedron Lett., 2016, 57, 3472-3475.
[http://dx.doi.org/10.1016/j.tetlet.2016.06.094]
[24]
Ghasemzadeh, M.S.; Akhlaghinia, B. γ-Fe2O3@SiO2-EC-ZnII: A magnetic recyclable nanocatalyst for the synthesis of spiro[indoline-3,9′-xanthene]trione derivatives in aqueous media. ChemistrySelect, 2018, 3, 3161-3170.
[http://dx.doi.org/10.1002/slct.201703189]
[25]
Piyali, S.; Chhanda, M. p-tert-Butylcalix[8]arene: An effective nano-ranged organocatalyst for the syntheses of xanthenes and acridines. Curr. Organocatal., 2016, 3, 205-215.
[http://dx.doi.org/10.2174/2213337202666150619173329]
[26]
Chen, C.; Lv, C.; Liang, J.; Jin, J.; Wang, L.; Wu, C.; Shen, R. An efficient synthesis of spiro[indoline-3,9′-xanthene]trione derivatives catalyzed by magnesium perchlorate. Molecules, 2017, 22(8), 1295.
[http://dx.doi.org/10.3390/molecules22081295] [PMID: 28777350]
[27]
Kourist, R.; González-Sabín, J. Non-conventional media as strategy to overcome the solvent dilemma in chemoenzymatic tandem catalysis. ChemCatChem, 2020, 12, 1903-1912.
[http://dx.doi.org/10.1002/cctc.201902192]
[28]
Gao, F.; Bai, R.X.; Ferlin, F.; Vaccaro, L.; Li, M.H.; Gu, Y.L. Replacement strategies for non-green dipolar aprotic solvents. Green Chem., 2020, 22, 6240-6257.
[http://dx.doi.org/10.1039/D0GC02149K]
[29]
Wei, L.; Chen, X.W.; Liu, Y.Y.; Wan, J.P. Recent advances in organic synthesis employing ethyl lactate as green reaction medium. Chin. J. Org. Chem., 2016, 36, 954-961.
[http://dx.doi.org/10.6023/cjoc201512014]
[30]
Xiao, L.W.; Dai, F.C.; Li, Z.; Jing, X.M.; Kong, J.; Liu, G.X. Polyethylene glycol: A new medium for green organic synthesis. Chin. J. Org. Chem., 2019, 39, 648-660.
[http://dx.doi.org/10.6023/cjoc201807056]
[31]
Zhang, Z.H.; Yin, L.; Wang, Y.M.; Liu, J.Y.; Li, Y. Indium tribromide in poly(ethylene glycol) (PEG): A novel and efficient recycle system for chemoselective deprotection of 1,1-diacetates. Green Chem., 2004, 6, 563-565.
[http://dx.doi.org/10.1039/b410583d]
[32]
Gadilohar, B.L.; Shankarling, G.S. Choline based ionic liquids and their applications in organic transformation. J. Mol. Liq., 2017, 227, 234-261.
[http://dx.doi.org/10.1016/j.molliq.2016.11.136]
[33]
Longo, L.S.; Craveiro, M.V. Deep eutectic solvents as unconventional media for multicomponent reactions. J. Braz. Chem. Soc., 2018, 29, 1999-2025.
[http://dx.doi.org/10.21577/0103-5053.20180147]
[34]
Paiva, A.; Craveiro, R.; Aroso, I.; Martins, M.; Reis, R.L.; Duarte, A.R.C. Natural deep eutectic solvents - solvents for the 21st century. ACS Sustain. Chem. & Eng., 2014, 2, 1063-1071.
[http://dx.doi.org/10.1021/sc500096j]
[35]
Liu, Y.; Friesen, J.B.; McAlpine, J.B.; Lankin, D.C.; Chen, S.N.; Pauli, G.F. Natural deep eutectic solvents: properties, applications, and perspectives. J. Nat. Prod., 2018, 81(3), 679-690.
[http://dx.doi.org/10.1021/acs.jnatprod.7b00945] [PMID: 29513526]
[36]
Perna, F.M.; Vitale, P.; Capriati, V. Deep eutectic solvents and their applications as green solvents. Curr. Opin. Green. Sustain. Chem., 2020, 21, 27-33.
[http://dx.doi.org/10.1016/j.cogsc.2019.09.004]
[37]
Alonso, D.A.; Baeza, A.; Chinchilla, R.; Guillena, G.; Pastor, I.M.; Ramón, D.J. Deep eutectic solvents: the organic reaction medium of the century. Eur. J. Org. Chem., 2016, 612-632.
[http://dx.doi.org/10.1002/ejoc.201501197]
[38]
Tan, J.N.; Dou, Y. Deep eutectic solvents for biocatalytic transformations: focused lipase-catalyzed organic reactions. Appl. Microbiol. Biotechnol., 2020, 104(4), 1481-1496.
[http://dx.doi.org/10.1007/s00253-019-10342-y] [PMID: 31907576]
[39]
Cicco, L.; Ríos-Lombardía, N.; Rodríguez-Álvarez, M.J.; Morís, F.; Perna, F.M.; Capriati, V.; García-Álvarez, J.; González-Sabín, J. Programming cascade reactions interfacing biocatalysis with transition-metal catalysis in deep eutectic solvents as biorenewable reaction media. Green Chem., 2018, 20, 3468-3475.
[http://dx.doi.org/10.1039/C8GC00861B]
[40]
Gotor-Fernández, V.; Paul, C.E. Deep eutectic solvents for redox biocatalysis. J. Biotechnol., 2019, 293, 24-35.
[http://dx.doi.org/10.1016/j.jbiotec.2018.12.018] [PMID: 30690099]
[41]
Tan, Y.T.; Chua, A.S.M.; Ngoh, G.C. Deep eutectic solvent for lignocellulosic biomass fractionation and the subsequent conversion to bio-based products - A review. Bioresour. Technol., 2020, 297, 122522.
[http://dx.doi.org/10.1016/j.biortech.2019.122522] [PMID: 31818720]
[42]
Jablonský, M.; Škulcová, A.; Šima, J. Use of deep eutectic solvents in polymer chemistry-A review. Molecules, 2019, 24(21), 3978.
[http://dx.doi.org/10.3390/molecules24213978] [PMID: 31684174]
[43]
Fernández, M.L.Á.; Boiteux, J.; Espino, M.; Gomez, F.J.V.; Silva, M.F. Natural deep eutectic solvents-mediated extractions: The way forward for sustainable analytical developments. Anal. Chim. Acta, 2018, 1038, 1-10.
[http://dx.doi.org/10.1016/j.aca.2018.07.059] [PMID: 30278889]
[44]
Cai, T.P.; Qiu, H.D. Application of deep eutectic solvents in chromatography: A review. TrAC, Trends Anal. Chem., 2019, 120, 115623.
[http://dx.doi.org/10.1016/j.trac.2019.115623]
[45]
Zhang, Y.Y.; Ji, X.Y.; Lu, X.H. Choline-based deep eutectic solvents for CO2 separation: Review and thermodynamic analysis. Renew. Sustain. Energy Rev., 2018, 97, 436-455.
[http://dx.doi.org/10.1016/j.rser.2018.08.007]
[46]
Chen, J.; Li, Y.; Wang, X.; Liu, W. Application of deep eutectic solvents in food analysis: A review. Molecules, 2019, 24(24), 4594.
[http://dx.doi.org/10.3390/molecules24244594] [PMID: 31888138]
[47]
Brett, C.M.A. Deep eutectic solvents and applications in electrochemical sensing. Curr. Opin. Electrochem., 2018, 10, 143-148.
[http://dx.doi.org/10.1016/j.coelec.2018.05.016]
[48]
Liu, P.; Hao, J.W.; Mo, L.P.; Zhang, Z.H. Recent advances in the application of deep eutectic solvents as sustainable media as well as catalysts in organic reactions. RSC Adv., 2015, 5, 48675-48704.
[http://dx.doi.org/10.1039/C5RA05746A]
[49]
Wu, C.; Xiao, H.J.; Wang, S.W.; Tang, M.S.; Tang, Z.L.; Xia, W.; Li, W.F.; Cao, Z.; He, W.M. Natural deep eutectic solvent-catalyzed selenocyanation of activated alkynes via an intermolecular H-bonding activation process. ACS Sustain. Chem. Eng., 2019, 7, 2169-2175.
[http://dx.doi.org/10.1021/acssuschemeng.8b04877]
[50]
Khandelwal, S.; Tailor, Y.K.; Kumar, M. Deep eutectic solvents (DESs) as eco-friendly and sustainable solvent/catalyst systems in organic transformations. J. Mol. Liq., 2016, 215, 345-386.
[http://dx.doi.org/10.1016/j.molliq.2015.12.015]
[51]
Gao, G.; Wang, P.; Liu, P.; Zhang, W.H.; Mo, L.P.; Zhang, Z.H. Deep eutectic solvent catalyzed one-pot synthesis of 4,7-dihydro-1H-pyrazolo[3,4-b]pyridine-5-carbonitriles. Chin. J. Org. Chem., 2018, 38, 846-854.
[http://dx.doi.org/10.6023/cjoc201711014]
[52]
Zhang, M.; Liu, Y.H.; Shang, Z.R.; Hu, H.C.; Zhang, Z.H. Supported molybdenum on graphene oxide/Fe3O4: An efficient, magnetically separable catalyst for one-pot construction of spiro-oxindole dihydropyridines in deep eutectic solvent under microwave irradiation. Catal. Commun., 2017, 88, 39-44.
[http://dx.doi.org/10.1016/j.catcom.2016.09.028]
[53]
Lu, J.; Li, X.T.; Ma, E.Q.; Mo, L.P.; Zhang, Z.H. Superparamagnetic CuFeO2 nanoparticles in deep eutectic solvent: an efficient and recyclable catalytic system for the synthesis of imidazo[1,2-a]pyridines. ChemCatChem, 2014, 6, 2854-285.
[http://dx.doi.org/10.1002/cctc.201402415]
[54]
Liu, P.; Hao, J.W.; Zhang, Z.H. A general, efficient and green procedure for synthesis of dihydropyrimidine-5-carboxamides in low melting betaine hydrochloride/urea mixture. Chin. J. Chem., 2016, 34, 637-645.
[http://dx.doi.org/10.1002/cjoc.201500862]
[55]
Peng, L.F.; Hu, Z.F.; Lu, Q.C.; Tang, Z.L.; Jiao, Y.C.; Xu, X.H. DESs: Green solvents for transition metal catalyzed organic reactions. Chin. Chem. Lett., 2019, 30(12), 2151-2156.
[http://dx.doi.org/10.1016/j.cclet.2019.05.063]
[56]
Atharifar, H.; Keivanloo, A.; Maleki, B. Greener synthesis of 3,4-disubstituted isoxazole-5(4H)-ones in a deep eutectic solvent. Org. Prep. Proced. Int., 2020, 52, 517-523.
[http://dx.doi.org/10.1080/00304948.2020.1799672]
[57]
Hooshmand, S.E.; Afshari, R.; Ramon, D.J.; Varma, R.S. Deep eutectic solvents: cutting-edge applications in cross-coupling reactions. Green Chem., 2020, 22, 3668-3692.
[http://dx.doi.org/10.1039/D0GC01494J]
[58]
Unlu, A.E.; Arikaya, A.; Takac, S. Use of deep eutectic solvents as catalyst: A mini-review. Green Process. Synth., 2019, 8, 355-372.
[http://dx.doi.org/10.1515/gps-2019-0003]
[59]
Lončarić, M.; Sušjenka, M.; Molnar, M. An Extensive study of coumarin synthesis via knoevenagel condensation in choline chloride based deep eutectic solvents. Curr. Org. Synth., 2020, 17(2), 98-108.
[http://dx.doi.org/10.2174/1570179417666200116155704] [PMID: 32418515]
[60]
Chen, G.Q.; Xie, Z.B.; Liu, Y.S.; Meng, J.; Le, Z.G. Synthesis of 2,4-disubstituted quinolines in deep eutectic solvents. Chin. J. Org. Chem., 2020, 40(1), 156-161.
[http://dx.doi.org/10.6023/cjoc201905040]
[61]
Inaloo, I.D.; Majnooni, S. Deep eutectic solvents (des) as green and efficient solvent/catalyst systems for the synthesis of carbamates and ureas from carbonates. ChemistrySelect, 2019, 4, 7811-7817.
[http://dx.doi.org/10.1002/slct.201901567]
[62]
Das, S.; Banik, R.; Kumar, B.; Roy, S.; Noorussabah,; Amhad, K.; Sukul, P.K. Noorussabah; Amhad, K.; Sukul, P.K. A Green approach for organic transformations using microwave reactor. Curr. Org. Synth., 2019, 16(5), 730-764.
[http://dx.doi.org/10.2174/1570179416666190412160048] [PMID: 31984890]
[63]
Gao, G.; Di, J.Q.; Zhang, H.Y.; Mo, L.P.; Zhang, Z.H. A magnetic metal organic framework material as a highly efficient and recyclable catalyst for synthesis of cyclohexenone derivatives. J. Catal., 2020, 387, 39-46.
[http://dx.doi.org/10.1016/j.jcat.2020.04.013]
[64]
Zhang, M.; Chen, M.N.; Zhang, Z.H. Visible light-initiated catalyst-free one-pot, multicomponent construction of 5-substituted indole chromeno[2,3-b]pyridines. Adv. Synth. Catal., 2019, 361, 5182-5190.
[http://dx.doi.org/10.1002/adsc.201900994]
[65]
Han, Y.; Zhang, M.; Zhang, Y.Q.; Zhang, Z.H. Copper immobilized at a covalent organic framework: an efficient and recyclable heterogeneous catalyst for the Chan-Lam coupling reaction of aryl boronic acids and amines. Green Chem., 2018, 20, 4891-4900.
[http://dx.doi.org/10.1039/C8GC02611D]

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