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Leonel G, Klann I, Back DF, Iglesias BA, Nogueira CW, Zeni G. Electrophile-Promoted Nucleophilic Cyclization of 2-Alkynylindoles to Give 4-Substituted Oxazinoindolones. Chemistry 2023; 29:e202202847. [PMID: 36322046 DOI: 10.1002/chem.202202847] [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: 10/13/2022] [Accepted: 11/02/2022] [Indexed: 12/23/2022]
Abstract
A method for the synthesis of 4-organoselanyl oxazinoindolone derivatives by the cascade cyclization of N-(alkoxycarbonyl)-2-alkynylindoles using iron(III) chloride and diorganyl diselenides as promoters was developed. This protocol was applied to a series of N-(alkoxycarbonyl)-2-alkynylindoles containing different substituents. The reaction conditions also tolerated a variety of diorganyl diselenides having both electron donating and electron withdrawing groups. However, the reaction did not work for diorganyl disulfides and ditellurides. The reaction mechanism seems to proceed via an ionic pathway and the cooperative action between iron(III) chloride and diorganyl diselenides is crucial for successful cyclization. We also found that using the same starting materials, by simply changing the electrophilic source to iodine, led to the formation of 4-iodo-oxazinoindolones. The high reactivity of Csp2 -Se and Csp2 -I bonds were tested under cross-coupling conditions leading to the preparation of a new class of functionalized indole derivatives. In addition, the absorption, emission and electrochemical properties of 4-organoselanyl oxazinoindolones showed an important relationship with the substituents of the aromatic rings. The advantages of the methodology include the use of electrophilic to promote the cyclization reaction and functionalization of the indole ring, and the electronic properties presented by the prepared compounds can be exploited as probes, analyte detectors and optical materials.
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Affiliation(s)
- Guilherme Leonel
- Laboratório de Síntese, Reatividade, Avaliação Farmacológica, Toxicológica de Organocalcogênios, CCNE, UFSM, Santa Maria, Rio Grande do Sul, 97105-900, Brazil
| | - Isabella Klann
- Laboratório de Síntese, Reatividade, Avaliação Farmacológica, Toxicológica de Organocalcogênios, CCNE, UFSM, Santa Maria, Rio Grande do Sul, 97105-900, Brazil
| | - Davi F Back
- Laboratório de Materiais Inorgânicos Departamento de Química, CCNE, UFSM, Santa Maria, Rio Grande do Sul, 97105-900, Brazil
| | - Bernardo A Iglesias
- Laboratório de Bioinorgânica e Materiais Porfirínicos Departamento de Química, CCNE, UFSM, Santa Maria, Rio Grande do Sul, 97105-900, Brazil
| | - Cristina W Nogueira
- Laboratório de Síntese, Reatividade, Avaliação Farmacológica, Toxicológica de Organocalcogênios, CCNE, UFSM, Santa Maria, Rio Grande do Sul, 97105-900, Brazil
| | - Gilson Zeni
- Laboratório de Síntese, Reatividade, Avaliação Farmacológica, Toxicológica de Organocalcogênios, CCNE, UFSM, Santa Maria, Rio Grande do Sul, 97105-900, Brazil
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Isfeld KA, Killeen C, Konowalchuk DJ, Davis RL. Exploring the catalytic role of the guanidine TBD in carboxylative cyclizations. Org Biomol Chem 2022; 20:5730-5734. [PMID: 35852820 DOI: 10.1039/d2ob01012g] [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
Employing a combination of mechanistic, kinetic and computational studies we have examined the mechanism of the TBD-catalyzed carboxylative cyclization of indole derivatives. Our studies provide insight into the role of the guanidine superbase TBD in catalyzing C-C bond formation between indole derivatives and CO2.
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Affiliation(s)
- Kaitlin A Isfeld
- Chemistry Department, University of Manitoba, 360 Parker Building, 144 Dysart Road, Winnipeg, Manitoba, Canada R3T 2N2.
| | - Charles Killeen
- Chemistry Department, University of Manitoba, 360 Parker Building, 144 Dysart Road, Winnipeg, Manitoba, Canada R3T 2N2.
| | - Dawson J Konowalchuk
- Chemistry Department, University of Manitoba, 360 Parker Building, 144 Dysart Road, Winnipeg, Manitoba, Canada R3T 2N2.
| | - Rebecca L Davis
- Chemistry Department, University of Manitoba, 360 Parker Building, 144 Dysart Road, Winnipeg, Manitoba, Canada R3T 2N2.
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Abstract
A silver-catalyzed carbon dioxide fixation reaction into 2-alkynylindole derivatives was developed to afford tricyclic indoles. Carbon dioxide was selectively fixed on the N atom of the indole, and only 6-endo-dig cyclization proceeded under mild reaction conditions. Carboxylation on C3 of the indole was not observed. This method was applicable for a variety of 2-alkynylindoles, and the corresponding products were obtained in high yields without the production of side products.
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Affiliation(s)
- Seiya Uema
- Department of Chemistry, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
| | - Kodai Saito
- Department of Chemistry, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
| | - Tohru Yamada
- Department of Chemistry, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
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Sarkar D, Amin A, Qadir T, Sharma PK. Synthesis of Medicinally Important Indole Derivatives: A Review. THE OPEN MEDICINAL CHEMISTRY JOURNAL 2021. [DOI: 10.2174/1874104502015010001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Indoles constitute a widely occurring functional group in nature and are present in an extensive number of bioactive natural products and medicinally important compounds. As a result, exponential increases in the development of novel methods for the formation of indole core along with site-specific indoles have been established. Conventional methods for the synthesis of indoles are getting replaced with green methods involving ionic liquids, water as a solvent, solid acid catalyst, microwave irradiation and the use of nanoparticles under solvent-free conditions. In addition, there are immense applications of the substituted indoles in diverse fields.
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