1
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Paul S, Choudhuri T, Das S, Pratap R, Bagdi AK. Tunable Regioselective Allylic Alkylation/Iodination of Imidazoheterocycles in Water. J Org Chem 2024; 89:1492-1504. [PMID: 38215401 DOI: 10.1021/acs.joc.3c02091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2024]
Abstract
The switchable roles of allylic alcohol and molecular iodine as reagents and catalysts have been demonstrated in the regioselective allylic alkylation and iodination of imidazoheterocycles employing the mixture of allylic alcohol-I2. First, we have explored the catalytic activity of iodine for the allylation of imidazoheterocycles using allylic alcohol in an aqueous medium. The allylation of a library of imidazoheterocycles and other electron-rich heterocycles like indole, pyrazole, 4-hydroxy coumarin, and 6-amino uracil has been achieved by employing this methodology. The efficiency of the I2 catalyst for N-allylation of azoles has also been demonstrated. Next, we have shown that this mixture of allylic alcohol and I2 could be beneficial for the iodination of imidazoheterocycles under room temperature. Mechanistic studies indicate that the activation of allylic alcohol by molecular iodine took place probably through halogen bonding, and NMR studies show that the reaction did not proceed through allylic ether formation.
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Affiliation(s)
- Suvam Paul
- Department of Chemistry, University of Kalyani, Kalyani 741235, India
| | | | - Sourav Das
- Department of Chemistry, University of Kalyani, Kalyani 741235, India
| | - Ramendra Pratap
- Department of Chemistry, University of Delhi, New Delhi 110007, India
| | - Avik Kumar Bagdi
- Department of Chemistry, University of Kalyani, Kalyani 741235, India
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2
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Deb ML, Baruah PK. Strategies Toward the Catalyst-Free α-C-H Functionalizations of Tertiary Amines. Top Curr Chem (Cham) 2023; 381:14. [PMID: 37131054 DOI: 10.1007/s41061-023-00424-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 03/24/2023] [Accepted: 04/02/2023] [Indexed: 05/04/2023]
Abstract
α-C-H functionalization of tertiary amines has been a highly studied field for the past two decades because several important nitrogen containing heterocycles or compounds can be synthesized through this strategy. Though transition metal catalysts and some metal-free catalysts are mainly used for these reactions, a few catalyst-free reactions have recently been efficiently performed. Catalyst-free reactions are cost-effective, less sensitive to air/moisture, easier to operate, have a simple purification process, and are relatively environment-friendly. In this article, we have summarized all the α-C-H functionalization reactions of tertiary amines performed without using any external catalysts. The content of this article will undoubtedly encourage readers to do more work in this area.
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Affiliation(s)
- Mohit L Deb
- Department of Applied Sciences, GUIST, Gauhati University, Guwahati, Assam, 781014, India.
| | - Pranjal K Baruah
- Department of Applied Sciences, GUIST, Gauhati University, Guwahati, Assam, 781014, India.
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Rahman I, Baruah B, Rajbongshi BK, Deb ML, Baruah PK. Catalyst‐/Additive‐Free One‐Pot Synthesis of Oxazolidines in Water via Regioselective and Stereoselective C−H Functionalization Approach. ChemistrySelect 2023. [DOI: 10.1002/slct.202300093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
Affiliation(s)
- Iftakur Rahman
- Department of Applied Sciences GUIST Gauhati University Guwahati 781014 Assam India
| | - Biswajita Baruah
- Department of Chemistry Pandu College Guwahati-781012 Assam India
| | | | - Mohit L. Deb
- Department of Applied Sciences GUIST Gauhati University Guwahati 781014 Assam India
| | - Pranjal K. Baruah
- Department of Applied Sciences GUIST Gauhati University Guwahati 781014 Assam India
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4
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Zou X, Zheng L, Zhuo X, Zhong Y, Wu Y, Yang B, He Q, Guo W. Copper-Promoted Aerobic Oxidative [3+2] Cycloaddition Reactions of N,N-Disubstituted Hydrazines with Alkynoates: Access to Substituted Pyrazoles. J Org Chem 2023; 88:2190-2206. [PMID: 36724037 DOI: 10.1021/acs.joc.2c02610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A copper-promoted aerobic oxidative [3+2] cycloaddition reaction for the synthesis of various substituted pyrazoles from N,N-disubstituted hydrazines with alkynoates in the presence of bases is developed. This work involves a direct C(sp3)-H functionalization and the formation of new C-C/C-N bonds. In this strategy, inexpensive and easily available Cu2O serves as the promoter and air acts as the green oxidant. The reaction exhibits the advantages of high atom and step economy, high regioselectivity, and easy operation.
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Affiliation(s)
- Xiaoying Zou
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, China
| | - Lvyin Zheng
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, China
| | - Xiaoya Zhuo
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, China
| | - Yumei Zhong
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, China
| | - Yingying Wu
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, China
| | - Beining Yang
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, China
| | - Qifang He
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, China
| | - Wei Guo
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University, Ganzhou 341000, China
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Qian BC, Zhu CZ, Shen GB. The Application of Sulfonyl Hydrazides in Electrosynthesis: A Review of Recent Studies. ACS OMEGA 2022; 7:39531-39561. [PMID: 36385900 PMCID: PMC9648049 DOI: 10.1021/acsomega.2c04205] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 10/13/2022] [Indexed: 05/25/2023]
Abstract
Sulfonyl hydrazides are viewed as alternatives to sulfinic acids and their salts or sulfonyl halides, which are broadly used in organic synthesis or work as active pharmaceutical substances. Generally, sulfonyl hydrazides are considered good building blocks and show powerful value in a diverse range of reactions to construct C-S bonds or C-C bonds, and even C-N bonds as sulfur, carbon, or nitrogen sources, respectively. As a profound synthetic tool, the electrosynthesis method was recently used to achieve efficient and green applications of sulfonyl hydrazides. Interestingly, many unique and novel electrochemical syntheses using sulfonyl hydrazides as radical precursors have been developed, including cascade reactions, functionalization of heterocycles, as well as a continuous flow method combining with electrochemical synthesis since 2017. Accordingly, it is necessary to specifically summarize the recent developments of electrosynthesis with only sulfonyl hydrazides as radical precursors to more deeply understand and better design novel electrochemical synthesis reactions. Herein, electrosynthesis research using sulfonyl hydrazides as radical precursors since 2017 is reviewed in detail based on the chemical structures of products and reaction mechanisms.
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Metal-Free Catalysis in C-C Single-Bond Cleavage: Achievements and Prospects. Top Curr Chem (Cham) 2022; 380:38. [PMID: 35951267 DOI: 10.1007/s41061-022-00393-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 05/30/2022] [Indexed: 10/15/2022]
Abstract
This review article emphasizes the C-C bond cleavage in organic synthesis via metal-free approach. Conventional organic synthesis mainly deals with the reactive π bonds and polar σ bonds. In contrast, the ubiquitous C-C single bonds are inherently stable and are less reactive, which poses a challenge to synthetic chemists. Although inert, such C-C single-bond cleavage reactions have gained attention amongst synthetic chemists, as they provide unique and more straightforward routes, with significantly fewer steps. Several review articles have been reported regarding the activation and cleavage of C-C bonds using different transition metals. However, given the high cost and toxicity of many of these metals, the development of strategies under metal-free conditions is of utmost importance. Though many research articles have been published in this area, no review article has been reported so far. Herein, we discuss the reactions in a more concise way from the year 2012 to today, with emphasis on important reactions. Mechanisms of all the reactions are also well addressed. We believe that this review will be beneficial for the readers who work in this field.
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Xu XJ, Amuti A, Hu WJ, Adelibieke Q, Wusiman A. TEMPO-Promoted Mono- and Bisimidation of Tertiary Anilines: Synthesis of Symmetric and Unsymmetric N-Mannich Bases. J Org Chem 2022; 87:9011-9022. [PMID: 35749377 DOI: 10.1021/acs.joc.2c00700] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A TEMPO-promoted method was developed for the synthesis of symmetric bis-N-Mannich bases via sequential activation of two α,α'-amino C(sp3)-H bonds of N,N-dimethylanilines under mild conditions. This methodology was further extended for monoimidation of α-amino-functionalized methylanilines to give unsymmetric N-Mannich bases in good to high yields. Several control experiments were performed, and the coupling reaction outcomes indicated that the oxoammonium (TEMPO+) species is involved in the reaction.
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Affiliation(s)
- Xiu Juan Xu
- School of Chemistry and Chemical Engineering, Xinjiang Normal University, Urumqi, Xinjiang 830054, P. R. of China
| | - Adila Amuti
- School of Chemistry and Chemical Engineering, Xinjiang Normal University, Urumqi, Xinjiang 830054, P. R. of China
| | - Wen Jing Hu
- School of Chemistry and Chemical Engineering, Xinjiang Normal University, Urumqi, Xinjiang 830054, P. R. of China
| | - Qiaerbati Adelibieke
- School of Chemistry and Chemical Engineering, Xinjiang Normal University, Urumqi, Xinjiang 830054, P. R. of China
| | - Abudureheman Wusiman
- School of Chemistry and Chemical Engineering, Xinjiang Normal University, Urumqi, Xinjiang 830054, P. R. of China.,Xinjiang Key Laboratory of Energy Storage and Photoelectrocatalytic Materials, Urumqi 830054, People's Republic of China
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Rastogi GK, Deka B, Deb ML, Baruah PK. Iodine‐DMSO‐promoted Oxygenation of Indoles: Synthesis of Isatin and Isoindigo. ASIAN J ORG CHEM 2022. [DOI: 10.1002/ajoc.202100757] [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)
- Gaurav K. Rastogi
- Department of Applied Sciences, GUIST Gauhati University Guwahati 781014 Assam India
- Department of Applied Organic Chemistry, CSIR-NEIST Jorhat 785006 Assam India
| | - Bhaskar Deka
- Department of Applied Sciences, GUIST Gauhati University Guwahati 781014 Assam India
| | - Mohit L. Deb
- Department of Applied Sciences, GUIST Gauhati University Guwahati 781014 Assam India
| | - Pranjal K. Baruah
- Department of Applied Sciences, GUIST Gauhati University Guwahati 781014 Assam India
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Deb ML, Saikia BS, Borpatra PJ, Baruah PK. Progress of metal‐free visible‐light‐driven a‐C‐H functionalization of tertiary amines: A decade journey. ASIAN J ORG CHEM 2021. [DOI: 10.1002/ajoc.202100706] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
| | | | | | - Pranjal K. Baruah
- GUIST, Gauhati University Applied Sciences Gopinath Bordoloi Nagar 781014 Guwahati INDIA
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Deka B, Rastogi GK, Deb ML, Baruah PK. Ten Years of Glory in the α-Functionalizations of Acetophenones: Progress Through Kornblum Oxidation and C-H Functionalization. Top Curr Chem (Cham) 2021; 380:1. [PMID: 34746982 DOI: 10.1007/s41061-021-00356-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 10/21/2021] [Indexed: 11/29/2022]
Abstract
This review article focuses on the α-functionalization of acetophenones involving Kornblum oxidation and C-H functionalizations. Although various other strategies, such as classical approaches, enamine approaches and umpolung strategy are also known for this functionalization, here we discuss mainly the Kornblum oxidation approach and C-H functionalization strategy as they have advantages over the others. In Kornblum oxidation, the reaction uses iodine and dimethylsulfoxide and proceeds through the formation of arylglyoxal as the key intermediate. In C-H functionalization, the reaction requires metal, or metal-free catalyst, and generates radical intermediate in most cases. α-Functionalization of acetophenones is very important because of their huge applications in the synthesis of various natural products and pharmaceuticals and, therefore, a number of research articles have been published in this area. However, no review articles are available so far. In this article, we present a succinct discussion of various important and novel reactions, along with their mechanisms, published since 2012 to date. We believe that this first review article in this field will give readers one-stop information on this topic and encourage further intriguing work in this area.
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Affiliation(s)
- Bhaskar Deka
- Department of Applied Sciences, GUIST, Gauhati University, Guwahati, Assam, 781014, India
| | - Gaurav K Rastogi
- Department of Applied Sciences, GUIST, Gauhati University, Guwahati, Assam, 781014, India
| | - Mohit L Deb
- Department of Applied Sciences, GUIST, Gauhati University, Guwahati, Assam, 781014, India
| | - Pranjal K Baruah
- Department of Applied Sciences, GUIST, Gauhati University, Guwahati, Assam, 781014, India.
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