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Theoretical Study on the Photo-Oxidation and Photoreduction of an Azetidine Derivative as a Model of DNA Repair. Molecules 2021; 26:molecules26102911. [PMID: 34068908 PMCID: PMC8157190 DOI: 10.3390/molecules26102911] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 05/08/2021] [Accepted: 05/11/2021] [Indexed: 11/17/2022] Open
Abstract
Photocycloreversion plays a central role in the study of the repair of DNA lesions, reverting them into the original pyrimidine nucleobases. Particularly, among the proposed mechanisms for the repair of DNA (6-4) photoproducts by photolyases, it has been suggested that it takes place through an intermediate characterized by a four-membered heterocyclic oxetane or azetidine ring, whose opening requires the reduction of the fused nucleobases. The specific role of this electron transfer step and its impact on the ring opening energetics remain to be understood. These processes are studied herein by means of quantum-chemical calculations on the two azetidine stereoisomers obtained from photocycloaddition between 6-azauracil and cyclohexene. First, we analyze the efficiency of the electron-transfer processes by computing the redox properties of the azetidine isomers as well as those of a series of aromatic photosensitizers acting as photoreductants and photo-oxidants. We find certain stereodifferentiation favoring oxidation of the cis-isomer, in agreement with previous experimental data. Second, we determine the reaction profiles of the ring-opening mechanism of the cationic, neutral, and anionic systems and assess their feasibility based on their energy barrier heights and the stability of the reactants and products. Results show that oxidation largely decreases the ring-opening energy barrier for both stereoisomers, even though the process is forecast as too slow to be competitive. Conversely, one-electron reduction dramatically facilitates the ring opening of the azetidine heterocycle. Considering the overall quantum-chemistry findings, N,N-dimethylaniline is proposed as an efficient photosensitizer to trigger the photoinduced cycloreversion of the DNA lesion model.
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Richardson AD, Becker MR, Schindler CS. Synthesis of azetidines by aza Paternò-Büchi reactions. Chem Sci 2020; 11:7553-7561. [PMID: 32832061 PMCID: PMC7408364 DOI: 10.1039/d0sc01017k] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 05/06/2020] [Indexed: 12/31/2022] Open
Abstract
This review discusses the current scope and limitations of the [2 + 2] photocycloaddition reaction between an imine and an alkene component, the aza Paternò–Büchi reaction, and highlights recent improvements within this area of research.
The [2 + 2] photocycloaddition reaction between an imine and an alkene component, the aza Paternò–Büchi reaction, is one of the most efficient ways to synthesize functionalized azetidines. However, the application of the aza Paternò–Büchi reaction has been met with limited success due to the inherent challenges associated with this approach. This review covers the current scope and limitations of reported examples of aza Paternò–Büchi reactions in organic synthesis. An outlook is provided, which highlights recent improvements and the discovery of new reaction protocols that have overcome some long-standing challenges within this field of research.
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Affiliation(s)
- Alistair D Richardson
- Willard Henry Dow Laboratory , Department of Chemistry , University of Michigan , Ann Arbor , MI 48109 , USA .
| | - Marc R Becker
- Willard Henry Dow Laboratory , Department of Chemistry , University of Michigan , Ann Arbor , MI 48109 , USA .
| | - Corinna S Schindler
- Willard Henry Dow Laboratory , Department of Chemistry , University of Michigan , Ann Arbor , MI 48109 , USA .
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Fraga-Timiraos AB, Francés-Monerris A, Rodríguez-Muñiz GM, Navarrete-Miguel M, Miranda MA, Roca-Sanjuán D, Lhiaubet-Vallet V. Experimental and Theoretical Study on the Cycloreversion of a Nucleobase-Derived Azetidine by Photoinduced Electron Transfer. Chemistry 2018; 24:15346-15354. [PMID: 30053323 DOI: 10.1002/chem.201803298] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Indexed: 12/16/2022]
Abstract
Azetidines are interesting compounds in medicine and chemistry as bioactive scaffolds and synthetic intermediates. However, photochemical processes involved in the generation and fate of azetidine-derived radical ions have scarcely been reported. In this context, the photoreduction of this four-membered heterocycle might be relevant in connection with the DNA (6-4) photoproduct obtained from photolyase. Herein, a stable azabipyrimidinic azetidine (AZTm ), obtained from cycloaddition between thymine and 6-azauracil units, is considered to be an interesting model of the proposed azetidine-like intermediate. Hence, its photoreduction and photo-oxidation are thoroughly investigated through a multifaceted approach, including spectroscopic, analytical, and electrochemical studies, complemented by CASPT2 and DFT calculations. Both injection and removal of an electron result in the formation of radical ions, which evolve towards repaired thymine and azauracil units. Whereas photoreduction energetics are similar to those of the cyclobutane thymine dimers, photo-oxidation is clearly more favorable in the azetidine. Ring opening occurs with relatively low activation barriers (<13 kcal mol-1 ) and the process is clearly exergonic for photoreduction. In general, a good correlation has been observed between the experimental results and theoretical calculations, which has allowed a synergic understanding of the phenomenon.
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Affiliation(s)
- Ana B Fraga-Timiraos
- Instituto de Tecnología Química UPV-CSIC, Universitat Politècnica de València, Consejo Superior de Investigaciones Científicas, Avenida de los Naranjos, s/n, 46022, Valencia, Spain
| | - Antonio Francés-Monerris
- Laboratoire de Physique et Chimie Théoriques (LPCT), Université de Lorraine, CNRS, 54000, Nancy, France
| | - Gemma M Rodríguez-Muñiz
- Instituto de Tecnología Química UPV-CSIC, Universitat Politècnica de València, Consejo Superior de Investigaciones Científicas, Avenida de los Naranjos, s/n, 46022, Valencia, Spain
| | - Miriam Navarrete-Miguel
- Instituto de Ciencia Molecular, Universitat de València, P.O. Box 22085, 46071, Valencia, Spain
| | - Miguel A Miranda
- Instituto de Tecnología Química UPV-CSIC, Universitat Politècnica de València, Consejo Superior de Investigaciones Científicas, Avenida de los Naranjos, s/n, 46022, Valencia, Spain
| | - Daniel Roca-Sanjuán
- Instituto de Ciencia Molecular, Universitat de València, P.O. Box 22085, 46071, Valencia, Spain
| | - Virginie Lhiaubet-Vallet
- Instituto de Tecnología Química UPV-CSIC, Universitat Politècnica de València, Consejo Superior de Investigaciones Científicas, Avenida de los Naranjos, s/n, 46022, Valencia, Spain
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Photorelaxation and Photorepair Processes in Nucleic and Amino Acid Derivatives. Molecules 2017; 22:molecules22122203. [PMID: 29231852 PMCID: PMC6149726 DOI: 10.3390/molecules22122203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 12/07/2017] [Accepted: 12/09/2017] [Indexed: 11/17/2022] Open
Abstract
Understanding the fundamental interaction between electromagnetic radiation and matter is essential for a large number of phenomena, with significance to civilization.[...].
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