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Mizuno Y, Nogata A, Suzuki M, Nakayama KI, Hisaki I, Kishi R, Konishi A, Yasuda M. Synthesis and Characterization of Dibenzothieno[ a, f]pentalenes Enabling Large Antiaromaticity and Moderate Open-Shell Character through a Small Energy Barrier for Bond-Shift Valence Tautomerization. J Am Chem Soc 2023; 145:20595-20609. [PMID: 37695346 DOI: 10.1021/jacs.3c07356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Experimental and theoretical rationalization of bond-shift valence tautomerization, characterized by double-well potential surfaces, is one of the most challenging topics of study among the rich electronic properties of antiaromatic molecules. Although the pseudo-Jahn-Teller effect (PJTE) is an essential effect to provide attractive characteristics of 4nπ systems, an understanding of the structure-property relationship derived from the PJTE for planar 4nπ electron systems is still in its infancy. Herein, we describe the synthesis and characterization of two regioisomers of the thiophene-fused diareno[a,f]pentalenes 6 and 7. The magnetic and optoelectronic properties characterize these sulfur-doped diareno[a,f]pentalenes as open-shell antiaromatic molecules, in sharp contrast to the closed-shell antiaromatic systems of 3 and 5, in which these main cores consist of the same number of π electrons as 6 and 7. Notably, thiophene-fused 6b and 7b showed pronounced antiaromaticity, the strongest among the previous systems, as well as moderate open-shell characteristics. Our experimental and theoretical investigations concluded that these properties of 6b and 7b are derived from the small energy barrier Ea‡ for the bond-shift valence tautomerization. The energy profile of the single crystal of 6b showed the temperature-dependent structural variations assigned to the dynamic mutual exchange between the two Cs-symmetric structures, which was also supported by changes in the chemical shifts of variable-temperature 1H NMR spectra in the solution phase. Both experimental and computational results revealed the importance of introducing heteroaromatic rings into 4nπ systems for controlling the PJTE and manifesting the antiaromatic and open-shell natures originating from the high-symmetric structure. The findings of this study advance the understanding of antiaromaticity characterized by the PJTE by controlling the energy barrier for bond-shift valence tautomerizations, potentially leading to the rational design of optoelectronic devices based on novel antiaromatic molecules possessing the strong contributions of their high-symmetric geometries.
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Affiliation(s)
- Yusuke Mizuno
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Akira Nogata
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Mitsuharu Suzuki
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Ken-Ichi Nakayama
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Ichiro Hisaki
- Division of Chemistry, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Ryohei Kishi
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
- Center for Quantum Information and Quantum Biology (QIQB), Osaka University, Toyonaka, Osaka 560-8531, Japan
- Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (ICS-OTRI), Osaka University, Suita, Osaka 565-0871, Japan
| | - Akihito Konishi
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
- Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (ICS-OTRI), Osaka University, Suita, Osaka 565-0871, Japan
| | - Makoto Yasuda
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
- Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (ICS-OTRI), Osaka University, Suita, Osaka 565-0871, Japan
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Fier PS, Roberts RA, Larson RT. The Direct Conversion of Esters to Ketones Enabled by a Traceless Activating Group. Org Lett 2023; 25:3131-3135. [PMID: 37099748 DOI: 10.1021/acs.orglett.3c00992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
We report here the design and development of a method for the single-step conversion of esters to ketones with simple reagents. The selective transformation of esters to ketones, rather than tertiary alcohols, is made possible by the use of a transient sulfinate group on the nucleophile that activates the adjacent carbon toward deprotonation to form a carbanion that adds to the ester, followed by a second deprotonation to prevent further addition. The resulting dianion undergoes spontaneous fragmentation of the SO2 group upon quenching with water to reveal the ketone product.
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Affiliation(s)
- Patrick S Fier
- Department of Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Riley A Roberts
- Department of Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Reed T Larson
- Department of Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
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Tolomeu HV, Fraga CAM. Imidazole: Synthesis, Functionalization and Physicochemical Properties of a Privileged Structure in Medicinal Chemistry. MOLECULES (BASEL, SWITZERLAND) 2023; 28:molecules28020838. [PMID: 36677894 PMCID: PMC9865940 DOI: 10.3390/molecules28020838] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 12/30/2022] [Accepted: 01/01/2023] [Indexed: 01/19/2023]
Abstract
Imidazole was first synthesized by Heinrich Debus in 1858 and was obtained by the reaction of glyoxal and formaldehyde in ammonia, initially called glyoxaline. The current literature provides much information about the synthesis, functionalization, physicochemical characteristics and biological role of imidazole. Imidazole is a structure that, despite being small, has a unique chemical complexity. It is a nucleus that is very practical and versatile in its construction/functionalization and can be considered a rich source of chemical diversity. Imidazole acts in extremely important processes for the maintenance of living organisms, such as catalysis in enzymatic processes. Imidazole-based compounds with antibacterial, anti-inflammatory, antidiabetic, antiparasitic, antituberculosis, antifungal, antioxidant, antitumor, antimalarial, anticancer, antidepressant and many others make up the therapeutic arsenal and new bioactive compounds proposed in the most diverse works. The interest and importance of imidazole-containing analogs in the field of medicinal chemistry is remarkable, and the understanding from the development of the first blockbuster drug cimetidine explores all the chemical and biological concepts of imidazole in the context of research and development of new drugs.
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Affiliation(s)
- Heber Victor Tolomeu
- Laboratório de Avaliação e Síntese de Substâncias Bioativas (LASSBio), Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-909, Brazil
- Programa de Pós-Graduação em Farmacologia e Química Medicinal, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-909, Brazil
| | - Carlos Alberto Manssour Fraga
- Laboratório de Avaliação e Síntese de Substâncias Bioativas (LASSBio), Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-909, Brazil
- Programa de Pós-Graduação em Farmacologia e Química Medicinal, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-909, Brazil
- Correspondence: ; Tel.: +55-21-39386447
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Deng J, Xiao J, Wang X, Luo H, Jia Z, Wang J. Iodine promoted reduction of aromatic carbonyl compounds with phosphonic acid to access hydrocarbons. Tetrahedron 2022. [DOI: 10.1016/j.tet.2022.132755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Zhao M, Yang Z, Yang D. Recent Progress in Synthesis of Polysubstituted Imidazoles by Cyclization Reaction. CHINESE J ORG CHEM 2022. [DOI: 10.6023/cjoc202107014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Zheng S, Smit W, Spannenberg A, Tin S, de Vries JG. Synthesis of α-Keto Aldehydes via Selective Cu(I)-catalyzed Oxidation of α-Hydroxy Ketones. Chem Commun (Camb) 2022; 58:4639-4642. [DOI: 10.1039/d2cc00773h] [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
An efficient approach to synthesize α-keto aldehydes was established through selective oxidation of α-hydroxy ketones catalyzed by Cu(I) using oxygen as oxidant. A wide array of α-keto aldehydes was prepared...
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Asressu KH, Chan CK, Wang CC. TMSOTf-catalyzed synthesis of trisubstituted imidazoles using hexamethyldisilazane as a nitrogen source under neat and microwave irradiation conditions. RSC Adv 2021; 11:28061-28071. [PMID: 35480777 PMCID: PMC9039414 DOI: 10.1039/d1ra05802a] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 08/12/2021] [Indexed: 12/15/2022] Open
Abstract
In the process of drug discovery and development, an efficient and expedient synthetic method for imidazole-based small molecules from commercially available and cheap starting materials has great significance. Herein, we developed a TMSOTf-catalyzed synthesis of trisubstituted imidazoles through the reaction of 1,2-diketones and aldehydes using hexamethyldisilazane as a nitrogen source under microwave heating and solvent-free conditions. The chemical structures of representative trisubstituted imidazoles were confirmed using X-ray single-crystal diffraction analysis. This synthetic method has several advantages including the involvement of mild Lewis acid, being metal- and additive-free, wide substrate scope with good to excellent yields and short reaction time. Furthermore, we demonstrate the application of the methodology in the synthesis of biologically active imidazole-based drugs. Trisubstituted imidazoles are synthesized efficiently from the readily available 1,2-diketones and aldehydes using hexamethyldisilazane as a new and stable nitrogen source under TMSOTf-catalysis system, microwave heating and solvent-free conditions.![]()
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Affiliation(s)
| | - Chieh-Kai Chan
- Institute of Chemistry, Academia Sinica Taipei 115 Taiwan
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Liu W, He J, Liu X, Yu Y, Pei Y, Zhu B, Cao H. Controllable Site-Selective Construction of 4- and 5-Hydroxyalkyl-Substituted Imidazoles from Amidines, Ynals, and Water. J Org Chem 2020; 85:14954-14962. [PMID: 33147029 DOI: 10.1021/acs.joc.0c01715] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The first example of controllable site-selective pathways to construct 4- and 5-hydroxyalkyl-substituted imidazoles through a three-component reaction of amidines, ynals, and water has been documented. Particularly, the high regioselectivity of the reaction was simply switched by changing the additives. In addition, further 18O-labeled experiments to probe a plausible mechanism and the gram-scale synthesis were studied.
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Affiliation(s)
- Wei Liu
- School of Chemistry and Chemical Engineering, Guangdong Pharmaceutical University, Zhongshan 528458, P. R. of China
| | - Jiaming He
- School of Chemistry and Chemical Engineering, Guangdong Pharmaceutical University, Zhongshan 528458, P. R. of China
| | - Xiang Liu
- School of Chemistry and Chemical Engineering, Guangdong Pharmaceutical University, Zhongshan 528458, P. R. of China
| | - Yue Yu
- School of Chemistry and Chemical Engineering, Guangdong Pharmaceutical University, Zhongshan 528458, P. R. of China
| | - Yongyan Pei
- School of Chemistry and Chemical Engineering, Guangdong Pharmaceutical University, Zhongshan 528458, P. R. of China
| | - Baofu Zhu
- School of Chemistry and Chemical Engineering, Guangdong Pharmaceutical University, Zhongshan 528458, P. R. of China
| | - Hua Cao
- School of Chemistry and Chemical Engineering, Guangdong Pharmaceutical University, Zhongshan 528458, P. R. of China
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Abstract
The review highlights the recent advances (2018-present) in the regiocontrolled synthesis of substituted imidazoles. These heterocycles are key components to functional molecules that are used in a variety of everyday applications. An emphasis has been placed on the bonds constructed during the formation of the imidazole. The utility of these methodologies based around the functional group compatibility of the process and resultant substitution patterns around the ring are described, including discussion of scope and limitations, reaction mechanisms and future challenges.
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Affiliation(s)
- Dmitrii A Shabalin
- A.E. Favorsky Irkutsk Institute of Chemistry SB RAS, 1 Favorsky St, Irkutsk, 664033, Russian Federation
| | - Jason E Camp
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
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Ramaiah MM, Babu Shubha P, Prasad H, Shivananju NS. Novel synthesis of N-unsubstituted imidazoles via the cycloaddition of N-(tert-butylsulfinyl)imines and TosMIC. Tetrahedron Lett 2020. [DOI: 10.1016/j.tetlet.2020.151705] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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