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Cardoso Barbosa JR, Queiroz MH, Rivelino R, Oliveira GDAR, Lião LM, Cunha S. Regioselectivity in the Nitration of Eugenol Is Independent of Inorganic Reagents: An Experimental and Theoretical Investigation with Synthetic and Mechanistic Implications. J Org Chem 2023. [PMID: 38153692 DOI: 10.1021/acs.joc.3c02298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2023]
Abstract
In this study, we reinvestigated the straightforward nitration of eugenol using traditional reagents and bismuth nitrate. NMR analysis of the obtained products revealed that the regioselectivity of eugenol nitration was independent of the inorganic nitrating reagent used, consistently resulting in the formation of 6-nitroeugenol. This contradicts previous literature reports because the elusive synthesis of 5-nitroeugenol using Bi(NO3)3·5H2O was not achievable through straightforward methods; instead, this isomer could only be prepared via the well-established three-step synthesis. Theoretical investigations using DFT calculations, considering both the dielectric constant of the medium and explicit water molecules, substantiated this regioselectivity. It was found that hydration water played a critical role in the formation of a Zundel cation, shifting the thermodynamic equilibrium toward the exclusive production of 6-nitroeugenol. These results imply that all biological studies involving eugenol derivatives synthesized via direct nitration with Bi(NO3)3·5H2O should be reviewed, as they dealt with 6-substituted eugenol derivatives rather than the previously assumed 5-substituted eugenol.
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Affiliation(s)
| | - Murillo H Queiroz
- Instituto de Química, Universidade Federal da Bahia, Campus de Ondina, Salvador, Bahia 40170-115, Brazil
| | - Roberto Rivelino
- Instituto de Física, Universidade Federal da Bahia, Salvador, Bahia 40210-340, Brazil
| | | | - Luciano Morais Lião
- Laboratório de RMN, Instituto de Química, Universidade Federal de Goiás, Goiânia, Goiás 74690-900, Brazil
| | - Silvio Cunha
- Instituto de Química, Universidade Federal da Bahia, Campus de Ondina, Salvador, Bahia 40170-115, Brazil
- Instituto Nacional de Ciência e Tecnologia-INCT em Energia e Ambiente, Campus Ondina, Salvador, Bahia 40170-290, Brazil
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Zhou Q, Du F, Chen Y, Fu Y, Sun W, Wu Y, Chen G. l -( -) -Quebrachitol as a Ligand for Selective Copper(0)-Catalyzed N-Arylation of Nitrogen-Containing Heterocycles. J Org Chem 2019; 84:8160-8167. [PMID: 31190531 DOI: 10.1021/acs.joc.9b00997] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
l-(-)-Quebrachitol (QCT) has been found as a ligand of copper powder for selective N-arylation of nitrogen-containing heterocycles with aryl halides. Furthermore, another potential catalytic system (copper powder/QCT/ t-BuOK) was successfully adapted to unactivated aryl chlorides.
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Affiliation(s)
- Qifan Zhou
- Key Laboratory of Structure-Based Drug Design & Discovery of Ministry of Education , Shenyang Pharmaceutical University , Shenyang 110016 , China
| | - Fangyu Du
- Key Laboratory of Structure-Based Drug Design & Discovery of Ministry of Education , Shenyang Pharmaceutical University , Shenyang 110016 , China
| | - Yuanguang Chen
- Key Laboratory of Structure-Based Drug Design & Discovery of Ministry of Education , Shenyang Pharmaceutical University , Shenyang 110016 , China
| | - Yang Fu
- Key Laboratory of Structure-Based Drug Design & Discovery of Ministry of Education , Shenyang Pharmaceutical University , Shenyang 110016 , China
| | - Wenjiao Sun
- Key Laboratory of Structure-Based Drug Design & Discovery of Ministry of Education , Shenyang Pharmaceutical University , Shenyang 110016 , China
| | - Ying Wu
- Yunnan Institute of Tropical Crops , Jinghong 666100 , China
| | - Guoliang Chen
- Key Laboratory of Structure-Based Drug Design & Discovery of Ministry of Education , Shenyang Pharmaceutical University , Shenyang 110016 , China
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Claramunt RM, Santa María D, Alkorta I, Elguero J. The Structure ofN-phenyl-pyrazoles and Indazoles: Mononitro, Dinitro, and Trinitro Derivatives. J Heterocycl Chem 2017. [DOI: 10.1002/jhet.3026] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Rosa M. Claramunt
- Departamento de Química Orgánica y Bio-Orgánica, Facultad de Ciencias; UNED; Paseo Senda del Rey, 9 28040 Madrid Spain
| | - Dolores Santa María
- Departamento de Química Orgánica y Bio-Orgánica, Facultad de Ciencias; UNED; Paseo Senda del Rey, 9 28040 Madrid Spain
| | - Ibon Alkorta
- Instituto de Química Médica, Centro de Química Orgánica “Manuel Lora-Tamayo”; CSIC; Juan de la Cierva, 3 28006 Madrid Spain
| | - José Elguero
- Instituto de Química Médica, Centro de Química Orgánica “Manuel Lora-Tamayo”; CSIC; Juan de la Cierva, 3 28006 Madrid Spain
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