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Sharma R, Chaudhary S. Regiodivergent Cu-Promoted, AcOH-Switchable Distal Versus Proximal Direct Cyanation of 1-Aryl-1 H-indazoles and 2-Aryl-2 H-indazoles via Aerobic Oxidative C-H Bond Activation. J Org Chem 2022; 87:16188-16203. [PMID: 36417354 DOI: 10.1021/acs.joc.2c01603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
A copper-promoted regiodivergent, AcOH-switchable, distal and proximal direct cyanation of N-aryl-(1H/2H)-indazoles via aerobic oxidative C(sp2)-H bond activation has been developed. The inclusion or exclusion of AcOH as an additive is the foremost cause for the positional switch in the C-CN bond formation method that results in (C-2')-cyanated 2-aryl-2H-indazoles 3a-j, (C-2')-cyanated 1-aryl-1H-indazoles 4a-j [distal], or C-3 cyanated 2-aryl-2H-indazoles 5a-i [proximal] products in good to excellent yields and showed various functional group tolerance. The cyanide (CN-) ion surrogate was generated via the unification of dimethylformamide and ammonium iodide (NH4I). The utilization of molecular oxygen (aerobic oxidative strategy) as a clean and safe oxidant is liable for generous value addition. The further pertinence of the developed protocol has been demonstrated by transforming the synthesized cyanated product into numerous other functional groups, which will, undoubtedly, accomplish utilization in the synthetic area of biologically important compounds and medicinal chemistry.
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Affiliation(s)
- Richa Sharma
- Laboratory of Organic and Medicinal Chemistry, Department of Chemistry, Malaviya National Institute of Technology, Jawaharlal Nehru Marg, Jaipur 302017, India
| | - Sandeep Chaudhary
- Laboratory of Organic and Medicinal Chemistry, Department of Chemistry, Malaviya National Institute of Technology, Jawaharlal Nehru Marg, Jaipur 302017, India.,Laboratory of Bioactive Heterocycles and Catalysis, Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research-Raebareli (Transit Campus), Bijnor-Sisendi Road, Near CRPF Base Camp, Sarojini Nagar, Lucknow 226002, India
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Yadav L, Shyamlal BRK, Tiwari MK, Rahaman T A A, Sen J, Chaudhary S. Unprecedented TMEDA-Catalyzed Regioselective Decarboalkoxy C-N Bond Formation: A Unified Direct Access to Indolo[2,1-a]isoquinoline and Dibenzopyrrocoline Alkaloids. Chem Asian J 2022; 17:e202200398. [PMID: 35615980 DOI: 10.1002/asia.202200398] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 05/24/2022] [Indexed: 11/09/2022]
Abstract
An unprecedented TMEDA-catalyzed, regioselective, decarboethoxy direct C-N coupling protocol towards the synthesis of dibenzopyrocolines 17a - i and 5,6-dihydroindolo[2,1 a ]isoquinoline 15a - f / 18a-c alkaloids via the identification of N,N,N',N'-tetramethylethylenediamine ( TMEDA ) as a homogeneous catalyst is reported. The transition-metal-free, TMEDA-catalytic novel protocol is operationally simple and showed a wide range of functional group tolerance and substrate compatibility. The gram-scale application and synthesis of naturally occurring Cryptaustoline (dibenzopyrocoline) alkaloid, further highlights the importance and versatile nature of the developed protocol. This finding also offers a TMEDA-catalyzed direct synthesis of dibenzopyrocolines and substituted 5,6dihydroindolo[2,1 -a ]isoquinoline compounds in a one-pot. The probable reaction pathway involves the free-radical sequential approach via a single electron transfer (SET) mechanism.
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Affiliation(s)
- Lalit Yadav
- Malaviya National Institute of Technology, Chemistry, Jawaharlal Nehru Marg, 302017, Jaipur, INDIA
| | | | - Mohit Kumar Tiwari
- Malaviya National Institute of Technology, Chemistry, Jawaharlal Nehru Marg, 302017, Jaipur, INDIA
| | - Abdul Rahaman T A
- National Institute of Pharmaceutical Education and Research Raebareli, Department of Medicinal Chemsitry, NIPER-Raebareli, Transit Campus,, Ahmedpur-Kamplapur, Bijnor-Sisendi Road, Sarojini Nagar, Near CRPF Base Camp, 226002, Lucknow, INDIA
| | - Janmejaya Sen
- National Institute of Pharmaceutical Education and Research Raebareli, Department of Medicinal Chemsitry, NIPER-Raebareli, Transit Campus,, Ahmedpur-Kamplapur, Bijnor-Sisendi Road, Sarojini Nagar, Near CRPF Base Camp, 226002, Lucknow, INDIA
| | - Sandeep Chaudhary
- National Institute of Pharmaceutical Education and Research Raebareli, Department of Medicinal Chemistry, Transit Campus, Ahmedpur-Kamplapur, Bijnor-Sisendi Road, Bijnor-Sisendi Road, Sarojini Nagar, Near CRPF Base Camp, Lucknow, India, 226002, Lucknow, INDIA
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Das TK, Kundu M, Mondal B, Ghosh P, Das S. Organocatalytic synthesis of (Het)biaryl scaffolds via photoinduced intra/intermolecular C(sp 2)-H arylation by 2-pyridone derivatives. Org Biomol Chem 2021; 20:208-218. [PMID: 34878476 DOI: 10.1039/d1ob01798e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A unique N,O-bidentate ligand 6-oxo-1,6-dihydro-pyridone-2-carboxylic acid dimethylamide (L1) catalyzed direct C(sp2)-H (intra/intermolecular) arylation of unactivated arenes has been developed to expedite access to (Het)biaryl scaffolds under UV-irradiation at room temperature. The protocol tolerated diverse functional groups and substitution patterns, affording the target products in moderate to excellent yields. Mechanistic investigations were also carried out to better understand the reaction pathway. Furthermore, the synthetic applicability of this unified approach has been showcased via the construction of biologically relevant 4-quinolone, tricyclic lactam and sultam derivatives.
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Affiliation(s)
- Tapas Kumar Das
- TCG Lifesciences Pvt. Ltd., BN-7, Sector V, Salt Lake City, Kolkata-700091, India. .,Department of Chemistry, University of North Bengal, Darjeeling, 734013, India.
| | - Mrinalkanti Kundu
- TCG Lifesciences Pvt. Ltd., BN-7, Sector V, Salt Lake City, Kolkata-700091, India.
| | - Biswajit Mondal
- TCG Lifesciences Pvt. Ltd., BN-7, Sector V, Salt Lake City, Kolkata-700091, India. .,Department of Chemistry, University of North Bengal, Darjeeling, 734013, India.
| | - Prasanjit Ghosh
- Department of Chemistry, University of North Bengal, Darjeeling, 734013, India.
| | - Sajal Das
- Department of Chemistry, University of North Bengal, Darjeeling, 734013, India.
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Yang L, Zhang CP. Revisiting the Balz-Schiemann Reaction of Aryldiazonium Tetrafluoroborate in Different Solvents under Catalyst- and Additive-Free Conditions. ACS OMEGA 2021; 6:21595-21603. [PMID: 34471763 PMCID: PMC8388107 DOI: 10.1021/acsomega.1c02825] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 08/04/2021] [Indexed: 05/04/2023]
Abstract
The thermal and photochemical Balz-Schiemann reaction in commonly used solvents was revisited under catalyst- and additive-free conditions. The study showed that using low- or non-polar solvents could improve the pyrolysis and photolysis of aryldiazonium tetrafluoroborates, enabling effective fluorination at a low temperature or under visible-light irradiation. PhCl and hexane were exemplified as cheap and reliable solvents for both reactions, providing good to excellent yields of aryl fluorides from the corresponding diazonium tetrafluoroborates. The combination of slight heating with visible-light irradiation was beneficial for the transformation of stable aryldiazonium tetrafluoroborates. Nevertheless, the electronic and steric nature of aryldiazonium tetrafluoroborates still had a pivotal effect on both fluorinations even in these solvents.
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Affiliation(s)
- Lian Yang
- School of Chemistry, Chemical
Engineering and Life Science, Wuhan University
of Technology, Wuhan 430070, China
| | - Cheng-Pan Zhang
- School of Chemistry, Chemical
Engineering and Life Science, Wuhan University
of Technology, Wuhan 430070, China
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