1
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Chouhan R, Gogoi A, Das SK. Constructing spirooxindoles from non-oxindole precursors: a one-pot nitro-reduction/double lactamization approach to spiro[indoline-3,3'-quinoline]-2,2'-diones. Org Biomol Chem 2024. [PMID: 39225015 DOI: 10.1039/d4ob01178c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
2-(2-Nitrobenzyl)-2-(2-nitrophenyl)malonates, readily prepared by SNAr-arylation of diethyl malonate with o-fluoronitrobenzenes, followed by SN2-alkylatioin of the resulting products with o-nitrobenzyl bromides, undergo a tandem Fe/AcOH-promoted nitro-reduction and double lactamization sequence to afford spiro[indoline-3,3'-quinoline]-2,2'-diones in high overall yields. The method is operationally simple, economical, and has a broad substrate scope. The synthetic practicality of this methodology was illustrated by performing the reaction on a gram scale with the same efficiency.
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Affiliation(s)
- Raju Chouhan
- Department of Chemical Sciences, Tezpur University, Napaam, Tezpur, Assam, India 784028.
| | - Abhijit Gogoi
- Department of Chemical Sciences, Tezpur University, Napaam, Tezpur, Assam, India 784028.
| | - Sajal Kumar Das
- Department of Chemical Sciences, Tezpur University, Napaam, Tezpur, Assam, India 784028.
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2
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Chouhan R, Bhattacharyya H, Das SK. Diastereocontrolled Construction of Spiroindolenines via Hexafluoroisopropanol-Promoted Dearomative Epoxide-Indole Cyclization. Org Lett 2024; 26:1088-1093. [PMID: 38271293 DOI: 10.1021/acs.orglett.3c04361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2024]
Abstract
Herein, we report the discovery of the ipso-selective, dearomatizing spirocyclization of indole-tethered epoxides as a fundamentally new approach for constructing spiroindolenines equipped with three contiguous stereogenic centers under complete diastereocontrol (dr >99:1) and in high yields. Promoted by hexafluoroisopropanol, the protocol features a broad substrate scope, easy scale-up, and versatile transformations of the synthesized spiroindolenines.
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Affiliation(s)
- Raju Chouhan
- Department of Chemical Sciences, Tezpur University, Napaam, Sonitpur, Assam 784028, India
| | - Hemanga Bhattacharyya
- Department of Chemical Sciences, Tezpur University, Napaam, Sonitpur, Assam 784028, India
| | - Sajal Kumar Das
- Department of Chemical Sciences, Tezpur University, Napaam, Sonitpur, Assam 784028, India
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3
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He X, Liu K, Yan S, Wang Y, Jiang Y, Zhang X, Fan X. Synthesis of 1,7-Fused Indolines Tethered with Spiroindolinone Based on C-H Activation Strategy with Air as a Sustainable Oxidant. J Org Chem 2024; 89:1880-1897. [PMID: 38252142 DOI: 10.1021/acs.joc.3c02630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2024]
Abstract
Herein, we present an efficient synthesis of 1,7-fused indolines tethered with a spiroindolinonyl moiety through the cascade reaction of indolin-1-yl(aryl)methanimines with diazo oxindoles. To the best of our knowledge, this is the first example in which 1,7-fused indoline skeleton was constructed along with the simultaneous introduction of a spiro element initiated by the C-H bond activation of indoline. In forming the title product, the indoline substrate and the diazo coupling partner demonstrated an unprecedented reaction pattern in which the latter acts as a C1 synthon to participate in the construction of the spirocyclic scaffold through the reductive elimination of a key seven-membered Ru(II) species by using air as an effective and sustainable oxidant to regenerate the active catalyst. Moreover, studies on the cytotoxicity of selected products against several human cancer cell lines demonstrated their potential as lead compounds for the development of anticancer drugs. With notable features such as simple and economical substrates, pharmaceutically valuable products with sophisticated spirocyclic skeleton, mild reaction conditions, cost-free and sustainable oxidants, high efficiency, excellent compatibility with diverse functional groups, and scalability, this method is expected to find wide applications in related areas.
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Affiliation(s)
- Xing He
- State Key Laboratory of Antiviral Drugs, Pingyuan Laboratory, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
| | - Kangli Liu
- State Key Laboratory of Antiviral Drugs, Pingyuan Laboratory, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
| | - Shengnan Yan
- State Key Laboratory of Antiviral Drugs, Pingyuan Laboratory, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
| | - Yue Wang
- State Key Laboratory of Antiviral Drugs, Pingyuan Laboratory, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
| | - Yuqin Jiang
- State Key Laboratory of Antiviral Drugs, Pingyuan Laboratory, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
| | - Xinying Zhang
- State Key Laboratory of Antiviral Drugs, Pingyuan Laboratory, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
| | - Xuesen Fan
- State Key Laboratory of Antiviral Drugs, Pingyuan Laboratory, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
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Das AJ, Das SK. Base-Mediated, Chemo- and Regioselective (4+2) Annulation of Indole-2-carboxamides with 2,3-Epoxy Tosylates toward 1,2-Fused Indoles. J Org Chem 2023. [PMID: 37289967 DOI: 10.1021/acs.joc.3c00813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Base-mediated [4+2] annulation of indole-2-carboxamides with 2,3-epoxy tosylates has been explored. The protocol delivers 3-substituted pyrazino[1,2-a]indol-1-ones in high yields in diastereoselective fashion, and neither 4-substituted pyrazino[1,2-a]indol-1-ones nor tetrahydro-1H-[1,4]diazepino[1,2-a]indol-1-ones are generated, irrespective of whether the distal epoxide C3 substituent is alkyl or aryl, or the epoxide is cis- or trans-configured. This reaction proceeds in one pot via N-alkylation of the indole scaffold with 2,3-epoxy tosylates, concomitantly followed by 6-exo-selective epoxide-opening cyclization. Notably, the process is chemo- and regioselective with respect to both the starting materials. To our knowledge, the process represents the first successful example of one-pot annulation of indole-based diheteronucleophiles with epoxide-based dielectrophiles.
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Affiliation(s)
- Arup Jyoti Das
- Department of Chemical Sciences, Tezpur University, Napaam, Sonitpur, Assam 784028, India
| | - Sajal Kumar Das
- Department of Chemical Sciences, Tezpur University, Napaam, Sonitpur, Assam 784028, India
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5
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Shan Y, Yang Z, Yu JT, Pan C. Metal-free polychloromethyl radical-initiated cyclization of unactivated N-allylindoles towards pyrrolo[1,2- a]indoles. Org Biomol Chem 2022; 20:5259-5263. [PMID: 35735246 DOI: 10.1039/d2ob00471b] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
A metal-free polychloromethyl radical-initiated cyclization of unactivated alkenes was developed using CH2Cl2 and CHCl3 as the di- and trichloromethyl radical sources. Variously substituted N-allyl-indoles were successfully transformed into the corresponding C2-(di- and trichloromethyl) pyrrolo[1,2-a]indoles in moderate to good yields. This reaction has a broad substrate scope and good functional group tolerance. Dibromomethylated products can also be obtained using CH2Br2 under standard conditions.
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Affiliation(s)
- Yujia Shan
- School of Petrochemical Engineering, Jiangsu Key Laboratory of Advanced Catalytic Materials & Technology, Changzhou University, Changzhou 213164, P. R. China.
| | - Zixian Yang
- School of Petrochemical Engineering, Jiangsu Key Laboratory of Advanced Catalytic Materials & Technology, Changzhou University, Changzhou 213164, P. R. China.
| | - Jin-Tao Yu
- School of Petrochemical Engineering, Jiangsu Key Laboratory of Advanced Catalytic Materials & Technology, Changzhou University, Changzhou 213164, P. R. China.
| | - Changduo Pan
- School of Chemical and Environmental Engineering, Jiangsu University of Technology, Changzhou 213001, P. R. China.
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Das AJ, Das SK. One-Pot Double Intramolecular Cyclization Approach to Tetralin-Based Cis-Fused Tetracyclic Compounds. J Org Chem 2022; 87:5085-5096. [PMID: 35333509 DOI: 10.1021/acs.joc.1c02963] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Presented herein is a BF3·OEt2-mediated, diastereoselective one-pot double cyclization of 4-aryl-2-[(arylthio)methyl]butanals leading to the formation of cis-tetrahydro-6H-naphtho[2,1-c]thiochromenes for the first time. Mechanistically, the formation of the title products involves the one-pot intramolecular Friedel-Crafts hydroxyalkylation/intramolecular Friedel-Crafts alkylation cascade. This synthetic methodology is featured by its high atom economy, broad substrate scope, mild transition-metal-free reaction conditions, capability to assemble two new rings in one pot, and moderate to high yields (up to 94% yield). It was then applied in the synthesis of a thia analogue of brazilane and a chromeno[3,4-c]chromene derivative. Moreover, the methodology was successfully extended to the synthesis of cis-hexahydrobenzo[c]phenanthrenes. Specifically, 1,5-diarylpentan-3-ones were first subjected to the Corey-Chaykovsky reaction, and the resulting epoxides, without being chromatographically isolated, were treated with BF3·OEt2 to afford the cyclized products in high yields (up to 84% yield over two steps).
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Affiliation(s)
- Arup Jyoti Das
- Department of Chemical Sciences, Tezpur University, Napaam, Sonitpur, Assam 784028, India
| | - Sajal Kumar Das
- Department of Chemical Sciences, Tezpur University, Napaam, Sonitpur, Assam 784028, India
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7
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Vayer M, Zhang S, Moran J, Lebœuf D. Rapid and Mild Metal-Free Reduction of Epoxides to Primary Alcohols Mediated by HFIP. ACS Catal 2022. [DOI: 10.1021/acscatal.2c00216] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Marie Vayer
- Université de Strasbourg, CNRS, ISIS UMR 7006, Strasbourg, 67000, France
| | - Shaofei Zhang
- Université de Strasbourg, CNRS, ISIS UMR 7006, Strasbourg, 67000, France
| | - Joseph Moran
- Université de Strasbourg, CNRS, ISIS UMR 7006, Strasbourg, 67000, France
| | - David Lebœuf
- Université de Strasbourg, CNRS, ISIS UMR 7006, Strasbourg, 67000, France
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8
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Das J, Borah BJ, Das SK. Construction of Benzosultam‐Containing Fused‐ and Linked‐Biheterocycles by a Cascade Double Nucleophilic Cyclization. European J Org Chem 2022. [DOI: 10.1002/ejoc.202101421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Jonali Das
- Tezpur University Chemical Sciences Tezpur 784028 Tezpur INDIA
| | | | - Sajal Kumar Das
- Tezpur University Chemical Sciences Napaam 784028 Tezpur INDIA
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9
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Banerjee A, Panda G. Transition metal-free, base mediated one-pot approach for the construction of the benzo[ b][1,4,5]oxathiazepine 1-oxide core. Org Biomol Chem 2022; 20:7112-7126. [DOI: 10.1039/d2ob01158a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Protocol for synthesising selected separable diastereomers of benzo[b][1,4,5]oxathiazepine 1-oxides via intermolecular epoxide ring opening by o-halogenated NH-sulfoximine followed by cyclisation and configurations were assigned by 2D NMR and X-ray crystallography.
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Affiliation(s)
- Arpita Banerjee
- Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, BS-10/1, Sector 10, Jankipuram Extension, Sitapur Road, P.O. Box 173, Lucknow 226031, India
| | - Gautam Panda
- Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, BS-10/1, Sector 10, Jankipuram Extension, Sitapur Road, P.O. Box 173, Lucknow 226031, India
- Academy of Scientific and Innovative Research, New Delhi 110001, India
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Das J, Das SK. Trifluoroethanol-promoted ring-opening cyclization of 4-(2-oxiranylmethoxy)indoles: access to 4,5-fused indoles. Org Biomol Chem 2021; 19:6761-6765. [PMID: 34286792 DOI: 10.1039/d1ob01030a] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein, we report that the trifluoroethanol-mediated ring-opening cyclization of readily accessible 4-(2-oxiranylmethoxy)indoles takes place in a diastereoselective and 6-endo fashion to generate pyrano[2,3-e]indol-3-ols in high yields. This regioselective cyclization at the indole C-5 position requires the presence of a π-activating aryl substituent on the reacting epoxide carbon atom, but remains uninfluenced by the electronic nature of the indole-N-substituent. Interestingly, blocking the C-5 position of the indole unit directs the reaction to generate oxepino[4,3,2-cd]indol-3-ols via 7-endo epoxide-arene cyclization.
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Affiliation(s)
- Jonali Das
- Department of Chemical Sciences, Tezpur University, Napaam, Tezpur, Assam, India-784028.
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