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Romanov AR, Kondrashov EV, Zinchenko SV. Synthesis of 5-(trifluoroacetyl)imidazoles from Bromoenones and Benzimidamides via Aza-Michael Initiated Ring Closure Reaction. Curr Org Synth 2024; 21:195-209. [PMID: 37078355 DOI: 10.2174/1570179420666230420100643] [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: 09/12/2022] [Revised: 02/08/2023] [Accepted: 02/21/2023] [Indexed: 04/21/2023]
Abstract
INTRODUCTION A simple method for the preparation of 5-(trifluoroacetyl)imidazoles was elaborated. METHODS The reaction of trifluoromethyl(α-bromoalkenyl)ketones with benzimidamides was employed to afford the target heterocycles in good yields. RESULTS The assembly of imidazole core proceeds via aza-Michael adduct formation followed by intramolecular nucleophilic substitution and spontaneous aromatization as an oxidation sequence. CONCLUSION The yields of target imidazoles can be improved by the use of soft oxidizing agents.
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Affiliation(s)
- Alexey R Romanov
- The Laboratory of Halogen Organic Compound, A. E. Favorsky Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Irkutsk, 664033, Russia
| | - Evgeniy V Kondrashov
- The Laboratory of Halogen Organic Compound, A. E. Favorsky Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Irkutsk, 664033, Russia
| | - Sergey V Zinchenko
- The Laboratory of Halogen Organic Compound, A. E. Favorsky Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Irkutsk, 664033, Russia
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Rubina SR, Leka SI, Priya KS, Kumar RR, Murugesan S. One‐Pot Three‐Component Domino Synthesis of Isoxazolo[5,4‐
b
]pyrano[2,3‐
f
]quinolines: An Efficient Fluorescent Turn‐off Chemosensor for Picric Acid. ChemistrySelect 2022. [DOI: 10.1002/slct.202203902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Affiliation(s)
- Stephen Raja Rubina
- School of Chemistry Madurai Kamaraj University Madurai 625021 Tamil Nadu INDIA
| | | | | | - Raju Ranjith Kumar
- School of Chemistry Madurai Kamaraj University Madurai 625021 Tamil Nadu INDIA
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Luque A, Paternoga J, Opatz T. Strain Release Chemistry of Photogenerated Small-Ring Intermediates. Chemistry 2021; 27:4500-4516. [PMID: 33080091 PMCID: PMC7986234 DOI: 10.1002/chem.202004178] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 10/16/2020] [Indexed: 12/20/2022]
Abstract
Photochemical processes, such as isomerizations and cycloadditions, have proven to be very useful in the construction of highly strained molecular frameworks. Photoinduced ring strain enables subsequent exergonic reactions which do not require the input of additional chemical energy and provides a variety of attractive synthetic options leading to complex structures. This review covers the progress achieved in the application of sequences combining excitation by ultraviolet light to form strained intermediates, which are further transformed to lower energy products in strain-release reactions. As ring strain is considerable in small ring systems, photogenerated three- and four-membered rings will be covered, mainly focusing on examples from 2000 to May 2020.
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Affiliation(s)
- Adriana Luque
- Department of ChemistryJohannes Gutenberg UniversityDuesbergweg 10–1455128MainzGermany
| | - Jan Paternoga
- Department of ChemistryJohannes Gutenberg UniversityDuesbergweg 10–1455128MainzGermany
| | - Till Opatz
- Department of ChemistryJohannes Gutenberg UniversityDuesbergweg 10–1455128MainzGermany
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Zhang XW, He XL, Yan N, Zheng HX, Hu XG. Oxidize Amines to Nitrile Oxides: One Type of Amine Oxidation and Its Application to Directly Construct Isoxazoles and Isoxazolines. J Org Chem 2020; 85:15726-15735. [PMID: 33174420 DOI: 10.1021/acs.joc.0c02281] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A facile oxidative heterocyclization of commercially available amines and tert-butyl nitrite with alkynes or alkenes leading to isoxazoles or isoxazolines is described. The unprecedented strategy of the oxidation of an amine directly to a nitrile oxide was used in this cyclization process. This reaction is highly efficient, regiospecific, operationally simple, mild, and tolerant of a variety of functional groups. Control experiments support a nitrile oxide intermediate mechanism for this novel class of oxidative cyclization reactions. Moreover, synthetic applications toward bioactive molecular skeletons and the late-stage modification of drugs were realized.
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Affiliation(s)
- Xiao-Wei Zhang
- National Engineering Research Center for Carbohydrate Synthesis, Jiangxi Normal University, 99 Ziyang Road, Nanchang, Jiangxi 330022, China.,School of Chemistry and Chemical Engineering, Liaocheng University, No. 1, Hunan Street, Liaocheng, Shandong 252059, China
| | - Xiao-Lin He
- National Engineering Research Center for Carbohydrate Synthesis, Jiangxi Normal University, 99 Ziyang Road, Nanchang, Jiangxi 330022, China.,School of Chemistry and Chemical Engineering, Liaocheng University, No. 1, Hunan Street, Liaocheng, Shandong 252059, China
| | - Nan Yan
- National Engineering Research Center for Carbohydrate Synthesis, Jiangxi Normal University, 99 Ziyang Road, Nanchang, Jiangxi 330022, China.,School of Chemistry and Chemical Engineering, Liaocheng University, No. 1, Hunan Street, Liaocheng, Shandong 252059, China
| | - Hong-Xing Zheng
- National Engineering Research Center for Carbohydrate Synthesis, Jiangxi Normal University, 99 Ziyang Road, Nanchang, Jiangxi 330022, China.,School of Chemistry and Chemical Engineering, Liaocheng University, No. 1, Hunan Street, Liaocheng, Shandong 252059, China
| | - Xiang-Guo Hu
- National Engineering Research Center for Carbohydrate Synthesis, Jiangxi Normal University, 99 Ziyang Road, Nanchang, Jiangxi 330022, China.,School of Chemistry and Chemical Engineering, Liaocheng University, No. 1, Hunan Street, Liaocheng, Shandong 252059, China
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