1
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Das KK, Hajra A. Non-directed oxidative annulation of 2-arylindazoles with electron deficient olefins via visible light photocatalysis. Chem Commun (Camb) 2024; 60:10402-10405. [PMID: 39224066 DOI: 10.1039/d4cc03657c] [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
A new visible-light-mediated non-directed oxidative annulation between 2-arylindazoles and electron-deficient olefins using commercially available piperidine-1-sulfonyl chloride as the radical precursor to afford fused 5,6-dihydroindazolo[2,3-a]quinolines has been developed under mild reaction conditions. This transformation occurs via two consecutive C-H bond functionalizations. The mechanistic investigation results indicate that the reaction progresses through a radical pathway forming a 2-(2-aryl-2H-indazol-3-yl)-3-piperidin-1-ylsulfonyl derivative as an intermediate.
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Affiliation(s)
- Krishna Kanta Das
- Department of Chemistry, Visva-Bharati (A Central University), Santiniketan, 731235, West Bengal, India.
| | - Alakananda Hajra
- Department of Chemistry, Visva-Bharati (A Central University), Santiniketan, 731235, West Bengal, India.
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2
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Manoharan K, Bieszczad B. Acyl-1,4-Dihydropyridines: Universal Acylation Reagents for Organic Synthesis. Molecules 2024; 29:3844. [PMID: 39202923 PMCID: PMC11356872 DOI: 10.3390/molecules29163844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2024] [Revised: 08/09/2024] [Accepted: 08/12/2024] [Indexed: 09/03/2024] Open
Abstract
Acyl-1,4-dihydropyridines have recently emerged as universal acylation reagents. These easy-to-make and bench-stable NADH biomimetics play the dual role of single-electron reductants and sources of acyl radicals. This review article discusses applications of acyl-1,4-dihydropyridines in organic synthesis since their introduction in 2019. Acyl-1,4-dihydropyridines, activated by photochemical, thermal or electrochemical methods, have been successfully applied as radical sources in multiple diverse organic transformations such as acyl radical addition to olefins, alkynes, imines and other acceptors, as well as in the late-stage functionalisation of natural products and APIs. Release of acyl radicals and an electron can be performed under mild conditions-in green solvents, under air and sunlight, and without the use of photocatalysts, photosensitizers or external oxidants-which makes them ideal reagents for organic chemists.
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Affiliation(s)
- Karthikeyan Manoharan
- Centre for Synthesis and Chemical Biology, School of Chemistry, University College Dublin, Belfield, D04 V1W8 Dublin, Ireland
| | - Bartosz Bieszczad
- Centre for Synthesis and Chemical Biology, School of Chemistry, University College Dublin, Belfield, D04 V1W8 Dublin, Ireland
- School of Chemical and Pharmaceutical Sciences, Technological University Dublin, City Campus, Grangegorman, D07 H6K8 Dublin, Ireland
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3
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Zhang Z, Wang J, Yu C, Tan J, Du H, Chen N. Visible-Light-Induced Acylative Pyridylation of Styrenes. Org Lett 2024. [PMID: 38809604 DOI: 10.1021/acs.orglett.4c01508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
A visible-light-induced photocatalyst-free acylative pyridylation of styrenes with 4-acyl-1,4-dihydropyridines (DHPs) and 4-cyanopyridines has been described, featuring mild reaction conditions, a broad substrate scope, and good functional group tolerance. The reaction could also be performed under sunlight irradiation albeit with a slightly lower conversion. 4-Acyl-1,4-DHPs serve a dual role, acting as both a photoreductant to reduce the cyanopyridine to its radical anion intermediate and a radical precursor to produce the acyl radical. The mechanism was especially elucidated through the Hammett analysis, with the quadratic linear regression analysis by using radical dual parameters, σmb and σjj·. The findings from Hammett analysis further demonstrate that the rate-limiting step of the process is the single electron transfer between 4-acyl-1,4-DHPs and 4-cyanopyridines.
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Affiliation(s)
- Zhiqin Zhang
- Department of Organic Chemistry, College of Chemistry, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
| | - Jianwei Wang
- Department of Organic Chemistry, College of Chemistry, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
| | - Chenfeng Yu
- Department of Organic Chemistry, College of Chemistry, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
| | - Jiajing Tan
- Department of Organic Chemistry, College of Chemistry, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
| | - Hongguang Du
- Department of Organic Chemistry, College of Chemistry, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
| | - Ning Chen
- Department of Organic Chemistry, College of Chemistry, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
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4
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Bhattacharjee S, Hajra A. Site-selective direct nitration of 2 H-indazoles: easy access to 7-nitroindazoles. Chem Commun (Camb) 2024; 60:4076-4079. [PMID: 38506140 DOI: 10.1039/d4cc00214h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2024]
Abstract
A new site-selective methodology for C-H nitration of 2H-indazoles has been accomplished at the C7 position using iron(III) nitrate. This strategy enables practical access to an array of 7-nitroindazoles with broad functional group tolerance in good yields. The synthesized products have been proven as valuable synthetic intermediates by demonstrating the synthetic utility. Mechanistic investigations indicate that the reaction goes through a radical pathway.
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Affiliation(s)
- Suvam Bhattacharjee
- Department of Chemistry, Visva-Bharati (A Central University), Santiniketan, 731235, West Bengal, India.
| | - Alakananda Hajra
- Department of Chemistry, Visva-Bharati (A Central University), Santiniketan, 731235, West Bengal, India.
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5
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Bhattacharjee S, Hajra A. Skeletal Editing through Molecular Recombination of 2H-Indazoles to Azo-Linked-Quinazolinones. Chemistry 2024; 30:e202303240. [PMID: 38019105 DOI: 10.1002/chem.202303240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 11/24/2023] [Accepted: 11/29/2023] [Indexed: 11/30/2023]
Abstract
A new protocol by the combinatory use of two equivalent of indazoles starting material with one being the carbon source via its C3-reactivity and the other, the coupling partner has been developed for the selectfluor-mediated single atom skeletal editing of 2H-indazoles. The azo-linked-2,3-disubstituted quinazolin-4-one derivatives were obtained through a carbon atom insertion between the two nitrogens of the indazole ring and simultaneous oxidation at C3 position of both indazole moieties. Mechanistic investigations reveal that the amidic carbonyl oxygen of the product is derived from water and the reaction proceeds through in-situ generated N-centred indazolone radical intermediate.
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Affiliation(s)
- Suvam Bhattacharjee
- Department of Chemistry, Visva-Bharati (A Central University), Santiniketan, 731235, West Bengal, India
| | - Alakananda Hajra
- Department of Chemistry, Visva-Bharati (A Central University), Santiniketan, 731235, West Bengal, India
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6
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Das KK, Hajra A. Silylation of 2 H-indazoles by photoinduced hydrogen atom transfer catalysis. Org Biomol Chem 2024; 22:1034-1037. [PMID: 38197231 DOI: 10.1039/d3ob01925j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
A metal-free, visible-light-mediated C-H silylation of 2H-indazoles with triphenylsilane has been developed employing 4CzIPN as a photocatalyst and triisopropylsilanethiol as a hydrogen atom transfer (HAT) reagent under aerobic reaction conditions. This method shows tolerance toward many functional groups and affords a variety of silylated indazoles at up to 89% yield. The experimental results suggest that the reaction progresses through a radical pathway.
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Affiliation(s)
- Krishna Kanta Das
- Department of Chemistry, Visva-Bharati (A Central University), Santiniketan, 731235, West Bengal, India.
| | - Alakananda Hajra
- Department of Chemistry, Visva-Bharati (A Central University), Santiniketan, 731235, West Bengal, India.
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7
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Kanta Das K, Kumar Ghosh A, Hajra A. One-Pot Manganese (I)-Catalyzed Oxidant-Controlled Divergent Functionalization of 2-Arylindazoles. Chemistry 2024; 30:e202302849. [PMID: 37870380 DOI: 10.1002/chem.202302849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/21/2023] [Accepted: 10/23/2023] [Indexed: 10/24/2023]
Abstract
The oxidant-controlled divergent synthesis of C-2' formyl 2H-indazoles and indazoloindazolediones has been developed through Mn(I)- catalyzed ortho C-H functionalization of 2H-indazoles with para-formaldehyde to afford C-2' hydroxymethylated 2H-indazoles and subsequently oxidation with varying the amount of DDQ in one-pot. By employing selectfluor as the oxidant instead of DDQ, this reaction exclusively provided indazolebenzoxazine derivatives. This strategy delivered unsymmetrical indazoloindazoledione and indazolobenzoxazine with varied functional group tolerance in moderate to good yields.
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Affiliation(s)
- Krishna Kanta Das
- Department of Chemistry, Visva-Bharati, A Central University), 731235, Santiniketanm, West Bengal, India
| | - Asim Kumar Ghosh
- Department of Chemistry, Visva-Bharati, A Central University), 731235, Santiniketanm, West Bengal, India
| | - Alakananda Hajra
- Department of Chemistry, Visva-Bharati, A Central University), 731235, Santiniketanm, West Bengal, India
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8
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Zhang G, Zhang Y, Li P, Zhou C, Wang M, Wang L. Metal-Free Synthesis of 2 H-Indazole Skeletons by Photochemistry or Thermochemistry. J Org Chem 2023; 88:12341-12356. [PMID: 37582245 DOI: 10.1021/acs.joc.3c01091] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/17/2023]
Abstract
A simple and tuned synthesis of a 2H-indazole skeleton under metal-free conditions was developed. Under visible-light irradiation at room temperature, 2-((aryl/alkyl/H)ethynyl))aryltriazenes reacted with arylsulfinic acids to afford 3-functionalized 2H-indazoles without extra photocatalyst via an electron donor-acceptor complex. In the presence of arylsulfinic acid, 2-(ethynyl)aryltriazenes underwent an intramolecular oxidation/cyclization to provide 2H-indazole-3-carbaldehydes at 50 °C in air.
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Affiliation(s)
- Gan Zhang
- Key Laboratory of Green and Precise Synthetic Chemistry and Applications, Ministry of Education and Department of Chemistry, Huaibei Normal University, Huaibei, Anhui 235000, P. R. China
| | - Yicheng Zhang
- Key Laboratory of Green and Precise Synthetic Chemistry and Applications, Ministry of Education and Department of Chemistry, Huaibei Normal University, Huaibei, Anhui 235000, P. R. China
| | - Pinhua Li
- Key Laboratory of Green and Precise Synthetic Chemistry and Applications, Ministry of Education and Department of Chemistry, Huaibei Normal University, Huaibei, Anhui 235000, P. R. China
| | - Chao Zhou
- Key Laboratory of Green and Precise Synthetic Chemistry and Applications, Ministry of Education and Department of Chemistry, Huaibei Normal University, Huaibei, Anhui 235000, P. R. China
| | - Min Wang
- Key Laboratory of Green and Precise Synthetic Chemistry and Applications, Ministry of Education and Department of Chemistry, Huaibei Normal University, Huaibei, Anhui 235000, P. R. China
| | - Lei Wang
- Key Laboratory of Green and Precise Synthetic Chemistry and Applications, Ministry of Education and Department of Chemistry, Huaibei Normal University, Huaibei, Anhui 235000, P. R. China
- Advanced Research Institute and School of Pharmaceutical Sciences, Taizhou University, Taizhou, Zhejiang 318000, P. R. China
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Scienes, Shanghai 200032, P. R. China
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9
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Bhati KS, Suwalka D, Verma VP, Jassal AK, Kumari N, Sharma S. Cell Voltage-Dependent Structural Dichotomy: Electrochemical C-H Acyloxylation and N-Acylation of 2 H-Indazoles. Org Lett 2023. [PMID: 37450634 DOI: 10.1021/acs.orglett.3c01649] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/18/2023]
Abstract
A simple and efficient electrochemical method that utilizes modulation of the cell voltage to cause structural alterations in 2H-indazole is introduced. This method enables the C-3 acyloxylation of 2H-indazole and promotes the transfer of the acyl group from C-3 to N-1, allowing the N-acylation of 2H-indazoles. Additionally, the application of the μ-electro flow reactor was demonstrated, showcasing its effectiveness in achieving gram-scale production of 3x within a short residence time.
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Affiliation(s)
- Kuldeep Singh Bhati
- Department of Chemistry, Mohanlal Sukhadia University, Udaipur 313001, India
| | - Dinesh Suwalka
- Department of Chemistry, Mohanlal Sukhadia University, Udaipur 313001, India
| | - Ved Prakash Verma
- Department of Chemistry, Banasthali University, Niwai-Jodhpuriya Road, Vanasthali 304022, India
| | - Amanpreet Kaur Jassal
- Department of Chemistry, U.G.C. Centre of Advanced Studies in Chemistry, Guru Nanak Dev University, Amritsar 143005, India
| | - Neetu Kumari
- Department of Chemistry, Mohanlal Sukhadia University, Udaipur 313001, India
| | - Siddharth Sharma
- Department of Chemistry, Mohanlal Sukhadia University, Udaipur 313001, India
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10
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Zhang L, Yan H, Fan Y, Luo X, Pan Y, Liu Y, Cai Y, Xia Q. Cu-Catalyzed Regioselective C-H Amination of 2 H-Indazoles for the Synthesis of Indazole-Containing Indazol-3(2 H)-ones. J Org Chem 2023; 88:5731-5744. [PMID: 36996408 DOI: 10.1021/acs.joc.3c00187] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/01/2023]
Abstract
A copper-catalyzed C3 amination of 2H-indazoles with 2H-indazoles and indazol-3(2H)-ones under mild conditions was developed. A series of indazole-containing indazol-3(2H)-one derivatives were produced in moderate to excellent yields. The mechanistic studies suggest that the reactions probably proceed through a radical pathway.
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Affiliation(s)
- Lina Zhang
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Hang Yan
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Yueyue Fan
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Xiande Luo
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Yingqiao Pan
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Yishu Liu
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Yuepiao Cai
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Qinqin Xia
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China
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11
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Photoinduced cyclization of aryl ynones with 4-alkyl-DHPs for the divergent synthesis of indenones, thioflavones and spiro[5.5]trienones. MOLECULAR CATALYSIS 2023. [DOI: 10.1016/j.mcat.2022.112819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
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12
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Sarkar A, Saha M, Das AR, Banerjee A, Majumder R, Bandyopadhyay D. Hypervalent iodine mediated Pd(II)‐catalyzed
ortho
‐C(
sp
2
−H) functionalization of azoles deciphering Hantzsch ester and malononitrile as the functional group surrogates. ChemistrySelect 2022. [DOI: 10.1002/slct.202203959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Anindita Sarkar
- Department of Chemistry University of Calcutta 92 APC Road Kolkata 700009 India
| | - Moumita Saha
- Department of Chemistry University of Calcutta 92 APC Road Kolkata 700009 India
| | - Asish R. Das
- Department of Chemistry University of Calcutta 92 APC Road Kolkata 700009 India
| | - Adrita Banerjee
- Department of Physiology University of Calcutta 92 APC Road Kolkata 700009 India
| | - Romit Majumder
- Department of Physiology University of Calcutta 92 APC Road Kolkata 700009 India
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13
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Yu WQ, Xiong BQ, Zhong LJ, Liu Y. Visible-light-promoted radical cascade alkylation/cyclization: access to alkylated indolo/benzoimidazo[2,1- a]isoquinolin-6(5 H)-ones. Org Biomol Chem 2022; 20:9659-9671. [PMID: 36416184 DOI: 10.1039/d2ob01732f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A new protocol is herein described for the direct generation of alkylated indolo/benzoimidazo[2,1-a]isoquinolin-6(5H)-one derivatives by using Hantzsch esters as alkylation radical precursors using a photoredox/K2S2O8 system. This oxidative alkylation of active alkenes involves a radical cascade cyclization process and a sequence of Hantzsch ester single electron oxidation, C-C bond cleavage, alkylation, arylation and oxidative deprotonation.
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Affiliation(s)
- Wen-Qin Yu
- Department of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006, China.
| | - Bi-Quan Xiong
- Department of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006, China.
| | - Long-Jin Zhong
- Department of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006, China.
| | - Yu Liu
- Department of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006, China.
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14
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Ma C, Shang L, Zhao H, He X, Lv Q, Zhang D, Jiang Y. Visible light-promoted transition metal-free direct C3-carbamoylation of 2H-Indazoles. Front Chem 2022; 10:1087834. [DOI: 10.3389/fchem.2022.1087834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 11/14/2022] [Indexed: 12/03/2022] Open
Abstract
We reported a general transition metal-free transformation to access C3-carbamoylated 2H-indazoles via visible light-induced oxidative decarboxylation coupling, in the presence of oxamic acids as the coupling sources, 4CzIPN as the photocatalyst, and Cs2CO3 as the base. The great application potential of this mild condition is highlighted by the late-stage modification of drugs, N-terminal modification of peptides, and the good antitumor activity of the novel desired product.
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15
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Yang Z, Yu JT, Pan C. Recent advances in C-H functionalization of 2 H-indazoles. Org Biomol Chem 2022; 20:7746-7764. [PMID: 36178474 DOI: 10.1039/d2ob01463g] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
2H-Indazoles are one class of the most important nitrogen-containing heterocyclic compounds. The 2H-indazole motif is widely present in bioactive natural products and drug molecules that exhibit distinctive bioactivities. Therefore, much attention has been paid to access diverse 2H-indazole derivatives. Among them, the late-stage functionalization of 2H-indazoles via C-H activation is recognized as an efficient approach for increasing the complexity and diversity of 2H-indazole derivatives. In this review, we summarized recent achievements in the late-stage functionalization of 2H-indazoles, including the C3-functionalization of 2H-indazoles through transition metal-catalyzed C-H activation or a radical pathway, transition metal-catalyzed ortho C2'-H functionalization of 2H-indazoles and remote C-H functionalization at the benzene ring in 2H-indazoles.
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Affiliation(s)
- Zixian Yang
- School of Petrochemical Engineering, Changzhou University, Changzhou 213164, P. R. China.
| | - Jin-Tao Yu
- School of Petrochemical Engineering, Changzhou University, Changzhou 213164, P. R. China.
| | - Changduo Pan
- School of Chemistry and Chemical Engineering, Jiangsu University of Technology, Changzhou 213001, P. R. China.
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16
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Xiong FT, He BH, Liu Y, Zhou Q, Fan JH. Iron-Promoted Oxidative Alkylation/Cyclization of Ynones with 4-Alkyl-1,4-dihydropyridines: Access to 2-Alkylated Indenones. J Org Chem 2022; 87:8599-8610. [PMID: 35704791 DOI: 10.1021/acs.joc.2c00766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An iron-promoted oxidative tandem alkylation/cyclization of ynones with 4-alkyl-substituted 1,4-dihydropyridines for the efficient synthesis of 2-alkylated indenones is described. The process occurs via oxidative homolysis of a C-C σ-bond in 1,4-dihydropyridines to generate an alkyl radical followed by the addition of C-C triple bonds in ynones and intramolecular cyclization. A wide range of alkyl radicals could be efficiently transferred to generate a series of synthetically useful 2-alkylated indenones with excellent selectivity under mild conditions.
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Affiliation(s)
- Fang-Ting Xiong
- Department of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006, China
| | - Bin-Hong He
- Department of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006, China
| | - Yu Liu
- Department of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006, China
| | - Quan Zhou
- Department of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006, China
| | - Jian-Hong Fan
- Department of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006, China
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17
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Chen P, Fan JH, Yu WQ, Xiong BQ, Liu Y, Tang KW, Xie J. Alkylation/Ipso-cyclization of Active Alkynes Leading to 3-Alkylated Aza- and Oxa-spiro[4,5]-trienones. J Org Chem 2022; 87:5643-5659. [PMID: 35416658 DOI: 10.1021/acs.joc.1c03118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A method for the preparation of 3-alkylated spiro[4.5]trienones via alkylation/ipso-cyclization of activated alkynes with 4-alkyl-DHPs under transition-metal-free conditions is proposed. This alkylation successively undergoes the generation of alkyl radicals, addition of alkyl radicals to the alkynes, and intramolecular ipso-cyclization. The mechanism studies suggest that the alkylation/ipso-cyclization involves a radical process. This ipso-cyclization procedure shows a series of advantages, such as accessibility, mild conditions, high efficiency, greater safety, and an environmentally friendly method.
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Affiliation(s)
- Pu Chen
- Department of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006, China
| | - Jian-Hong Fan
- Department of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006, China
| | - Wen-Qin Yu
- Department of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006, China
| | - Bi-Quan Xiong
- Department of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006, China
| | - Yu Liu
- Department of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006, China
| | - Ke-Wen Tang
- Department of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006, China
| | - Jun Xie
- Department of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006, China
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18
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Wang B, Zhong X, Yao H, Deng R, Yan Z, Gao M, Sen L. Direct alkylation and acylation of 2H‐indazoles using aldehydes under metal‐free conditions. ASIAN J ORG CHEM 2022. [DOI: 10.1002/ajoc.202200152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Bingqing Wang
- Nanchang University - Qianhu Campus: Nanchang University department of chemistry CHINA
| | - Xiaoyang Zhong
- Nanchang University - Qianhu Campus: Nanchang University department of chemistry CHINA
| | - Hua Yao
- Nanchang University - Qianhu Campus: Nanchang University department of chemistry CHINA
| | - Ruihong Deng
- Nanchang University - Qianhu Campus: Nanchang University department of chemistry CHINA
| | - Zhaohua Yan
- Nanchang University - Qianhu Campus: Nanchang University department of chemistry CHINA
| | - Mengjiao Gao
- Nanchang University Medical College: Medical College of Nanchang University department of medical CHINA
| | - Lin Sen
- Nanchang University Department of Chemistry Nangchang University 330000 Nangchang CHINA
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19
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Ma C, Zhao L, He X, Jiang Y, Yu B. Visible-light-induced Direct 3-Ethoxycarbonylmethylation of 2-Aryl-2H-Indazoles in Water. Org Chem Front 2022. [DOI: 10.1039/d1qo01870a] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A visible-light-driven Rhodamine B-catalyzed transition-metal-free 3-ethoxycarbonylmethylation of 2-aryl-2H-indazoles and imidazo[1,2-a]pyridines (40 examples) using commercially available α-bromoesters was realized in water. This protocol features sustainable, operational simplicity, mild reaction conditions, and...
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20
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Wang J, Song Q, He X, Ma C, Jiang Y, Fan J. Visible light-promoted, photocatalyst-free decarboxylative alkylations of 2H-indazoles via electron donor-acceptor-complex activation. NEW J CHEM 2022. [DOI: 10.1039/d2nj02766f] [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
A transition-metal-free and traditional dye-free visible light-driven directly alkylation of 2-aryl-2H-indazoles was developed in the catalytic of an electron donor-acceptor (EDA) complex among alkyl N-hydroxyphthalimide (NHPI) esters, triphenylphosphine (PPh3), and...
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21
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Yao Z, Zhang X, Luo Z, Pan Y, Zhao H, Li B, Xu L, Shi Q, Fan Q. Na
2
S
2
O
8
‐Mediated Tandem One‐Pot Construction of 3,3‐Disubsituted 3,4‐Dihydroquinoxalin‐2(1
H
)‐ones with 4‐Alkyl‐1,4‐dihydropyridines as Alkyl Radical Sources. ASIAN J ORG CHEM 2022. [DOI: 10.1002/ajoc.202100609] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Zhen Yao
- Department of Chemistry Renmin University of China Beijing 100872 P. R. China
| | - Xin Zhang
- Department of Chemistry Renmin University of China Beijing 100872 P. R. China
| | - Zhenli Luo
- Department of Chemistry Renmin University of China Beijing 100872 P. R. China
| | - Yixiao Pan
- Department of Chemistry Renmin University of China Beijing 100872 P. R. China
| | - Haoqiang Zhao
- Department of Chemistry Renmin University of China Beijing 100872 P. R. China
| | - Bohan Li
- Department of Chemistry Renmin University of China Beijing 100872 P. R. China
| | - Lijin Xu
- Department of Chemistry Renmin University of China Beijing 100872 P. R. China
| | - Qian Shi
- College of Chemistry & Materials Engineering Wenzhou University Wenzhou 325035 P. R. China
| | - Qing‐Hua Fan
- Institute of Chemistry Chinese Academy of Sciences
- University of Chinese Academy of Sciences Beijing 100190 P. R. China
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22
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Sahu AK, Biswas S, Bora SK, Saikia AK. Synthesis of 3 C-alkylated active methylene substituted 2 H-indazole derivatives via sequential ring opening of donor–acceptor cyclopropanes and reductive cyclization reaction. NEW J CHEM 2022. [DOI: 10.1039/d2nj01801b] [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
A facile synthesis of 3C-alkylated active methylene substituted 2H-indazoles from o-nitrocyclopropanes and primary arylamines catalyzed by Ni(ClO4)2.6H2O/SnCl2.2H2O is reported.
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Affiliation(s)
- Archana Kumari Sahu
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Subhamoy Biswas
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Surjya Kumar Bora
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Anil K. Saikia
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
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23
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Yu WQ, Fan JH, Chen P, Xiong B, Xie J, Tang K, Liu Y. Transition-Metal-Free Alkylation Strategy: A Facile Access of Alkylated Oxindoles via Alkyl Transfer. Org Biomol Chem 2022; 20:1958-1968. [DOI: 10.1039/d2ob00019a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An efficient transition-metal-free alkylation/cyclization of activated alkenes using Hantzsch ester derivatives as effective alkyl reagents was described. A wide variety of valuable oxindoles were constructed in a single step with...
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24
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Rhodium-catalyzed directed C–H functionalization of 2-arylindazoles with diazotized Meldrum's acid. J Organomet Chem 2021. [DOI: 10.1016/j.jorganchem.2021.122009] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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25
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Shen GB, Xie L, Wang YX, Gong TY, Wang BY, Hu YH, Fu YH, Yan M. Quantitative Estimation of the Hydrogen-Atom-Donating Ability of 4-Substituted Hantzsch Ester Radical Cations. ACS OMEGA 2021; 6:23621-23629. [PMID: 34549160 PMCID: PMC8444320 DOI: 10.1021/acsomega.1c03872] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 08/19/2021] [Indexed: 05/22/2023]
Abstract
The purpose of this study is to investigate thermodynamic and kinetic properties on the hydrogen-atom-donating ability of 4-substituted Hantzsch ester radical cations (XRH•+), which are excellent NADH coenzyme models. Gibbs free energy changes and activation free energies of 17 XRH•+ releasing H• [denoted as ΔG HD o(XRH•+) and ΔG HD ≠(XRH•+)] were calculated using density functional theory (DFT) and compared with that of Hantzsch ester (HEH2) and NADH. ΔG HD o(XRH•+) range from 19.35 to 31.25 kcal/mol, significantly lower than that of common antioxidants (such as ascorbic acid, BHT, the NADH coenzyme, and so forth). ΔG HD ≠(XRH•+) range from 29.81 to 39.00 kcal/mol, indicating that XRH•+ spontaneously releasing H• are extremely slow unless catalysts or active intermediate radicals exist. According to the computed data, it can be inferred that the Gibbs free energies and activation free energies of the core 1,4-dihydropyridine radical cation structure (DPH•+) releasing H• [ΔG HD o(DPH•+) and ΔG HD ≠(DPH•+)] should be 19-32 kcal/mol and 29-39 kcal/mol in acetonitrile, respectively. The correlations between the thermodynamic driving force [ΔG HD o(XRH•+)] and the activation free energy [ΔG HD ≠(XRH•+)] are also explored. Gibbs free energy is the important and decisive parameter, and ΔG HD ≠(XRH•+) increases in company with the increase of ΔG HD o(XRH•+), but no simple linear correlations are found. Even though all XRH•+ are judged as excellent antioxidants from the thermodynamic view, the computed data indicate that whether XRH•+ is an excellent antioxidant in reaction is decided by the R substituents in 4-position. XRH•+ with nonaromatic substituents tend to release R• instead of H• to quench radicals. XRH•+ with aromatic substituents tend to release H• and be used as antioxidants, but not all aromatic substituted Hantzsch esters are excellent antioxidants.
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Affiliation(s)
- Guang-Bin Shen
- School of Medical Engineering, Jining Medical University, Jining, Shandong 272000, P. R. China
| | - Li Xie
- School of Medical Engineering, Jining Medical University, Jining, Shandong 272000, P. R. China
| | - Yun-Xia Wang
- School of Medical Engineering, Jining Medical University, Jining, Shandong 272000, P. R. China
| | - Teng-Yang Gong
- School of Pharmacy, Jining Medical University, Rizhao, Shandong 276800, P. R. China
| | - Bin-Yu Wang
- School of Medical Engineering, Jining Medical University, Jining, Shandong 272000, P. R. China
| | - Yu-He Hu
- School of Medical Engineering, Jining Medical University, Jining, Shandong 272000, P. R. China
| | - Yan-Hua Fu
- College of Chemistry and Environmental Engineering, Anyang Institute of Technology, Anyang, Henan 455000, P. R. China
| | - Maocai Yan
- School of Pharmacy, Jining Medical University, Rizhao, Shandong 276800, P. R. China
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Abstract
An efficient, simple, and metal-free fluorination of 2H-indazoles has been developed using N-fluorobenzenesulfonimide (NFSI) in water under ambient air. This transformation provides direct access to fluorinated indazole derivatives with broad functionalities in satisfactory yields. The experimental results suggest a radical mechanistic pathway of this protocol.
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Affiliation(s)
- Payel Ghosh
- Department of Chemistry, Visva-Bharati (A Central University), Santiniketan 731235, India
| | - Alakananda Hajra
- Department of Chemistry, Visva-Bharati (A Central University), Santiniketan 731235, India
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28
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Liu L, Deng Z, Xu K, Jiang P, Du H, Tan J. Access to Deuterated Unnatural α-Amino Acids and Peptides by Photochemical Acyl Radical Addition. Org Lett 2021; 23:5299-5304. [PMID: 34170137 DOI: 10.1021/acs.orglett.1c01448] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A visible-light-enabled, photocatalyst-free conjugate addition reaction of dehydroamino acids is disclosed. Employing 4-acyl-1,4-dihydropyridines as both a radical reservoir and reductant, various β-acyl α-amino acids and their deuterated analogues were obtained in good results. Both late-stage peptide modification and stereoselective synthesis of chiral oxazolidinones are successfully achieved. The protocol is characterized by mild conditions and efficient derivatization, thus unlocking a novel blueprint to access unnatural amino acid derivatives, important building blocks with potential application in the peptidomimetic toolbox.
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Affiliation(s)
- Li Liu
- Department of Organic Chemistry, College of Chemistry, Beijing University of Chemical Technology (BUCT), Beijing 100029, People's Republic of China
| | - Zikun Deng
- Department of Organic Chemistry, College of Chemistry, Beijing University of Chemical Technology (BUCT), Beijing 100029, People's Republic of China
| | - Kun Xu
- Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, People's Republic of China
| | - Pengxing Jiang
- Department of Organic Chemistry, College of Chemistry, Beijing University of Chemical Technology (BUCT), Beijing 100029, People's Republic of China
| | - Hongguang Du
- Department of Organic Chemistry, College of Chemistry, Beijing University of Chemical Technology (BUCT), Beijing 100029, People's Republic of China
| | - Jiajing Tan
- Department of Organic Chemistry, College of Chemistry, Beijing University of Chemical Technology (BUCT), Beijing 100029, People's Republic of China
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29
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Luo X, Wang P. Ynonylation of Acyl Radicals by Electroinduced Homolysis of 4-Acyl-1,4-dihydropyridines. Org Lett 2021; 23:4960-4965. [PMID: 34155886 DOI: 10.1021/acs.orglett.1c01243] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Herein we report the conversion of 4-acyl-1,4-dihydropyridines (DHPs) into ynones under electrochemical conditions. The reaction proceeds via the homolysis of acyl-DHP under electron activation. The resulting acyl radicals react with hypervalent iodine(III) reagents to form the target ynones or ynamides in acceptable yields. This mild reaction condition allows wider functionality tolerance that includes halides, carboxylates, or alkenes. The synthetic utility of this methodology is further demonstrated by the late-stage modification of complex molecules.
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Affiliation(s)
- Xiaosheng Luo
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Ping Wang
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai 200240, China
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30
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Li ZH, Wang WB, Qin JJ, Ye LX, He JY, Xie YY. Silver-catalyzed radical reaction of 2H-indazoles with 1,3-dicarbonyl compounds to access 3-dicarbonyl indazoles. Tetrahedron 2021. [DOI: 10.1016/j.tet.2021.132227] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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31
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Wang XY, Li Y, Shi L, Zhu X, Hao XQ, Song MP. Palladium-catalyzed C–H acetoxylation of 2-arylindazoles. Tetrahedron 2021. [DOI: 10.1016/j.tet.2021.132277] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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32
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Affiliation(s)
| | - Anna Lee
- Department of Chemistry Jeonbuk National University Jeonju 54896 Republic of Korea
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33
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Jiang P, Liu L, Tan J, Du H. Visible-light-promoted photocatalyst-free alkylation and acylation of benzothiazoles. Org Biomol Chem 2021; 19:4487-4491. [PMID: 33960996 DOI: 10.1039/d1ob00734c] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Herein we report a protocol for the visible-light-mediated alkylation/acylation reaction of benzothiazoles. Alkyl/acyl substituted Hantzsch esters are easily prepared and rationally used as radical precursors. In the presence of BF3·Et2O and Na2S2O8, various benzothiazole derivatives were readily obtained in good yields. Our user-friendly protocol can proceed by simple irradiation with blue LEDs (λ = 465 nm) and without the assistance of external photocatalysts. The reaction is also characterized by mild conditions and scalability, thus offering an alternative and efficient tool for the synthesis of 2-functionalized benzothiazoles.
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Affiliation(s)
- Pengxing Jiang
- Department of Organic Chemistry, College of Chemistry, Beijing University of Chemical Technology (BUCT), Beijing 100029, China.
| | - Li Liu
- Department of Organic Chemistry, College of Chemistry, Beijing University of Chemical Technology (BUCT), Beijing 100029, China.
| | - Jiajing Tan
- Department of Organic Chemistry, College of Chemistry, Beijing University of Chemical Technology (BUCT), Beijing 100029, China.
| | - Hongguang Du
- Department of Organic Chemistry, College of Chemistry, Beijing University of Chemical Technology (BUCT), Beijing 100029, China.
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34
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Sharma R, Yadav L, Yadav RK, Chaudhary S. Oxidative cross-dehydrogenative coupling (CDC) via C (sp2)-H bond functionalization: tert-butyl peroxybenzoate (TBPB)-promoted regioselective direct C-3 acylation/benzoylation of 2 H-indazoles with aldehydes/benzyl alcohols/styrenes. RSC Adv 2021; 11:14178-14192. [PMID: 35423939 PMCID: PMC8698059 DOI: 10.1039/d1ra02225c] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Accepted: 03/26/2021] [Indexed: 12/14/2022] Open
Abstract
An efficient, cost-effective, transition-metal-free, oxidative C(sp2)–H/C(sp2)–H cross-dehydrogenative coupling via a C(sp2)–H bond functionalization protocol for the regioselective direct C-3 acylation/benzoylation of substituted 2H-Indazoles 1a–m with substituted aldehydes 2a–q/benzyl alcohols 5a–e/styrenes 6a–e is reported. The operationally simple protocol proceeds in the presence of tert-butyl peroxybenzoate (TBPB) as an oxidant in chlorobenzene (PhCl) as a solvent at 110 °C for 24 h under an inert atmosphere, which furnished a diverse variety of substituted 3-(acyl/benzoyl)-2H-indazoles 3a–q/4a–l in up to 87% yields. The reaction involves a free-radical mechanism and proceeds via the addition of an in situ generated acyl radical (from aldehydes/benzyl alcohols/styrenes) on 2H-indazoles. The functional group tolerance, broad substrate scope, control/competitive experiments and gram-scale synthesis and its application to the synthesis of anti-inflammatory agent 11 and novel indazole-fused diazepine 13 further signify the versatile nature of the developed methodology. An efficient transition-metal-free oxidative C(sp2)–H/C(sp2)–H cross-dehydrogenative coupling via C(sp2)–H bond functionalization for regioselective C-3 acylation/benzoylation of 2H-indazoles with aldehydes/benzyl alcohols/styrenes is reported.![]()
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Affiliation(s)
- Richa Sharma
- Laboratory of Organic and Medicinal Chemistry (OMC Lab), Department of Chemistry, Malaviya National Institute of Technology Jawaharlal Nehru Marg Jaipur-302017 India +911412529029 +911412713319
| | - Lalit Yadav
- Laboratory of Organic and Medicinal Chemistry (OMC Lab), Department of Chemistry, Malaviya National Institute of Technology Jawaharlal Nehru Marg Jaipur-302017 India +911412529029 +911412713319
| | - Ravi Kant Yadav
- Laboratory of Organic and Medicinal Chemistry (OMC Lab), Department of Chemistry, Malaviya National Institute of Technology Jawaharlal Nehru Marg Jaipur-302017 India +911412529029 +911412713319
| | - Sandeep Chaudhary
- Laboratory of Organic and Medicinal Chemistry (OMC Lab), Department of Chemistry, Malaviya National Institute of Technology Jawaharlal Nehru Marg Jaipur-302017 India +911412529029 +911412713319
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35
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Affiliation(s)
- Feng Liu
- School of Perfume and Aroma Technology Shanghai Institute of Technology 100 Haiquan Rd. Shanghai 201418 P. R. China
- Department of Chemistry Fudan University 2005 Songhu Rd. Shanghai 200438 P. R. China
| | - Zhen Zhang
- School of Perfume and Aroma Technology Shanghai Institute of Technology 100 Haiquan Rd. Shanghai 201418 P. R. China
| | - Hai‐yan Diao
- School of Perfume and Aroma Technology Shanghai Institute of Technology 100 Haiquan Rd. Shanghai 201418 P. R. China
| | - Zhang‐jie Shi
- Department of Chemistry Fudan University 2005 Songhu Rd. Shanghai 200438 P. R. China
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36
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Shinde VN, Rangan K, Kumar D, Kumar A. Rhodium(III)-Catalyzed Dehydrogenative Annulation and Spirocyclization of 2-Arylindoles and 2-(1H-Pyrazol-1-yl)-1H-indoles with Maleimides: A Facile Access to Isogranulatimide Alkaloid Analogues. J Org Chem 2021; 86:2328-2338. [DOI: 10.1021/acs.joc.0c02467] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Vikki N. Shinde
- Department of Chemistry, Birla Institute of Technology and Science Pilani, Pilani Campus, Rajasthan 333031, India
| | - Krishnan Rangan
- Department of Chemistry, Birla Institute of Technology and Science Pilani, Hyderabad Campus, Telangana 500078, India
| | - Dalip Kumar
- Department of Chemistry, Birla Institute of Technology and Science Pilani, Pilani Campus, Rajasthan 333031, India
| | - Anil Kumar
- Department of Chemistry, Birla Institute of Technology and Science Pilani, Pilani Campus, Rajasthan 333031, India
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37
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Sun M, Zhou Y, Li L, Wang L, Ma Y, Li P. Electrochemically promoted C-3 amination of 2H-indazoles. Org Chem Front 2021. [DOI: 10.1039/d0qo01088j] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A metal-free and external oxidant-free method for the C-3 amination of 2H-indazoles in good yields was developed under electrochemical conditions.
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Affiliation(s)
- Mingli Sun
- Advanced Research Institute and Department of Chemistry
- Taizhou University
- Taizhou
- People's Republic of China
- Department of Chemistry
| | - Yuhui Zhou
- Advanced Research Institute and Department of Chemistry
- Taizhou University
- Taizhou
- People's Republic of China
| | - Laiqiang Li
- Department of Chemistry
- Huaibei Normal University
- Huaibei
- P. R. China
| | - Lei Wang
- Advanced Research Institute and Department of Chemistry
- Taizhou University
- Taizhou
- People's Republic of China
- Department of Chemistry
| | - Yongmin Ma
- Advanced Research Institute and Department of Chemistry
- Taizhou University
- Taizhou
- People's Republic of China
| | - Pinhua Li
- Department of Chemistry
- Huaibei Normal University
- Huaibei
- P. R. China
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38
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Ma C, Feng Z, Li J, Zhang D, Li W, Jiang Y, Yu B. Photocatalytic transition-metal-free direct 3-alkylation of 2-aryl-2 H-indazoles in dimethyl carbonate. Org Chem Front 2021. [DOI: 10.1039/d1qo00064k] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A general transition-metal-free photocatalytic decarboxylative 3-alkylation reaction of 2-aryl-2H-indazoles was developed under visible-light irradiation under mild conditions.
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Affiliation(s)
- Chunhua Ma
- Collaborative Innovation Centre of Henan Province for Green Manufacturing of Fine Chemicals
- Key Laboratory of Green Chemical Media and Reactions
- Ministry of Education
- Henan Engineering Research Centre of Chiral Hydroxyl Pharmaceutical
- Henan Engineering Laboratory of Chemical Pharmaceutical and Biomedical Materials
| | - Zhiwen Feng
- Collaborative Innovation Centre of Henan Province for Green Manufacturing of Fine Chemicals
- Key Laboratory of Green Chemical Media and Reactions
- Ministry of Education
- Henan Engineering Research Centre of Chiral Hydroxyl Pharmaceutical
- Henan Engineering Laboratory of Chemical Pharmaceutical and Biomedical Materials
| | - Jing Li
- Collaborative Innovation Centre of Henan Province for Green Manufacturing of Fine Chemicals
- Key Laboratory of Green Chemical Media and Reactions
- Ministry of Education
- Henan Engineering Research Centre of Chiral Hydroxyl Pharmaceutical
- Henan Engineering Laboratory of Chemical Pharmaceutical and Biomedical Materials
| | - Dandan Zhang
- Collaborative Innovation Centre of Henan Province for Green Manufacturing of Fine Chemicals
- Key Laboratory of Green Chemical Media and Reactions
- Ministry of Education
- Henan Engineering Research Centre of Chiral Hydroxyl Pharmaceutical
- Henan Engineering Laboratory of Chemical Pharmaceutical and Biomedical Materials
| | - Wei Li
- Collaborative Innovation Centre of Henan Province for Green Manufacturing of Fine Chemicals
- Key Laboratory of Green Chemical Media and Reactions
- Ministry of Education
- Henan Engineering Research Centre of Chiral Hydroxyl Pharmaceutical
- Henan Engineering Laboratory of Chemical Pharmaceutical and Biomedical Materials
| | - Yuqin Jiang
- Collaborative Innovation Centre of Henan Province for Green Manufacturing of Fine Chemicals
- Key Laboratory of Green Chemical Media and Reactions
- Ministry of Education
- Henan Engineering Research Centre of Chiral Hydroxyl Pharmaceutical
- Henan Engineering Laboratory of Chemical Pharmaceutical and Biomedical Materials
| | - Bing Yu
- Green Catalysis Centre
- College of Chemistry
- Zhengzhou University
- Zhengzhou 450001
- China
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39
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Ghosh AK, Ghosh P, Hajra A. Rhodium-Catalyzed Directed C(sp 2)-H Bond Addition of 2-Arylindazoles to N-Sulfonylformaldimines and Activated Aldehydes. J Org Chem 2020; 85:15752-15759. [PMID: 33185096 DOI: 10.1021/acs.joc.0c02408] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Rhodium-catalyzed directed C-H functionalization of 2-arylindazoles with N-sulfonylformaldimines has been developed to provide a variety of N-benzylarylsulfonamide derivatives with good to excellent yields. Different activated aldehydes like ethyl glyoxalate and 2,2,2-trifluoroacetaldehyde also efficiently underwent nucleophilic addition with 2-arylindazoles. These selective transformations occur through the control of C3 nucleophilicity of indazole moiety. Mechanistic studies suggest that C-H activation step may be a rate-limiting step.
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Affiliation(s)
- Asim Kumar Ghosh
- Department of Chemistry, Visva-Bharati (A Central University), Santiniketan 731235, India
| | - Payel Ghosh
- Department of Chemistry, Visva-Bharati (A Central University), Santiniketan 731235, India
| | - Alakananda Hajra
- Department of Chemistry, Visva-Bharati (A Central University), Santiniketan 731235, India
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40
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Jaspal S, Shinde VN, Meena N, Nipate DS, Rangan K, Kumar A. Metal-free benzoylation of imidazoheterocycles by oxidative decarboxylation of arylglyoxylic acids. Org Biomol Chem 2020; 18:9072-9080. [DOI: 10.1039/d0ob01842b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A simple and straightforward approach has been realized for the direct benzoylation of imidazoheterocycles by oxidative decarboxylation of arylglyoxylic acids in the presence of K2S2O8 as an oxidant.
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Affiliation(s)
- Sonam Jaspal
- Department of Chemistry
- Birla Institute of Technology and Science Pilani
- Pilani Campus
- India
| | - Vikki N. Shinde
- Department of Chemistry
- Birla Institute of Technology and Science Pilani
- Pilani Campus
- India
| | - Neha Meena
- Department of Chemistry
- Birla Institute of Technology and Science Pilani
- Pilani Campus
- India
| | - Dhananjay S. Nipate
- Department of Chemistry
- Birla Institute of Technology and Science Pilani
- Pilani Campus
- India
| | - Krishnan Rangan
- Department of Chemistry
- Birla Institute of Technology and Science Pilani
- India
| | - Anil Kumar
- Department of Chemistry
- Birla Institute of Technology and Science Pilani
- Pilani Campus
- India
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