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Ribes J, Bourdeau Y, Rascol E, Bestel I, Badarau E. Enhancing the photosensitizing activity of natural flavins: Tuning the heavy-atom effect in the isoalloxazine series. Bioorg Med Chem 2023; 81:117210. [PMID: 36791612 DOI: 10.1016/j.bmc.2023.117210] [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: 11/25/2022] [Revised: 02/04/2023] [Accepted: 02/06/2023] [Indexed: 02/12/2023]
Abstract
Structure-photosensitizing activity relationships for a series of flavin analogues were investigated with the final goal of identifying the most potent photosensitizer in these series. The main structural modifications involved the introduction of various halogen atoms in C7- and/or C8-positions on the isoalloxazine ring. These compounds were synthesized by reacting judiciously-functionalized anilines with alloxan. The SAR trends showed that the photosensitizing activity increased with the size of the halogen atoms, confirming the importance of the heavy-atom effect on the photosensitizer's activity. The halogens in C8 were more active than the di-substituted halogens, which in turn were more active than the C7-substituted equivalents. However, even if the photosensitizing activity is slightly less important for the 7- compared to the 8-substituted derivatives, the 7-haloisoalloxazines are promising photosensitizers, as they present a better cellular toxicity profile than the 8-substituted analoges. The photosensitizing activity perfectly correlated with the determined fluorescence for the same compounds. Except for the dihalogeno derivatives, all the compounds were not toxic up to a 50 μM range.
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Affiliation(s)
- Jonathan Ribes
- University of Bordeaux, CNRS, CBMN, UMR 5248, Institute of Chemistry and Biology of Membranes & Nano-objects (CBMN), Allée Geoffroy Saint Hilaire, Bât B14, 33600 Pessac, France
| | - Yann Bourdeau
- University of Bordeaux, CNRS, CBMN, UMR 5248, Institute of Chemistry and Biology of Membranes & Nano-objects (CBMN), Allée Geoffroy Saint Hilaire, Bât B14, 33600 Pessac, France
| | - Estelle Rascol
- University of Bordeaux, CNRS, CBMN, UMR 5248, Institute of Chemistry and Biology of Membranes & Nano-objects (CBMN), Allée Geoffroy Saint Hilaire, Bât B14, 33600 Pessac, France
| | - Isabelle Bestel
- University of Bordeaux, CNRS, CBMN, UMR 5248, Institute of Chemistry and Biology of Membranes & Nano-objects (CBMN), Allée Geoffroy Saint Hilaire, Bât B14, 33600 Pessac, France
| | - Eduard Badarau
- University of Bordeaux, CNRS, CBMN, UMR 5248, Institute of Chemistry and Biology of Membranes & Nano-objects (CBMN), Allée Geoffroy Saint Hilaire, Bât B14, 33600 Pessac, France.
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Song Q, Lei X, Yang S, Wang S, Wang J, Chen J, Xiang Y, Huang Q, Wang Z. Continuous-Flow Synthesis of Nitro- o-xylenes: Process Optimization, Impurity Study and Extension to Analogues. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27165139. [PMID: 36014379 PMCID: PMC9416712 DOI: 10.3390/molecules27165139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 08/04/2022] [Accepted: 08/09/2022] [Indexed: 11/16/2022]
Abstract
An efficient continuous-flow nitration process of o-xylene at pilot scale was demonstrated. The effects of parameters such as temperature, ratio of H2SO4 to HNO3, H2SO4 concentration, flow rate, and residence time on the reaction were studied. Under the optimal conditions, the yield of products reached 94.1%, with a product throughput of 800 g/h. The main impurities of this continuous-flow nitration process were also studied in detail. Compared with batch process, phenolic impurity decreased from 2% to 0.1%, which enabled the omission of the alkaline solution washing step and thus reduced the wastewater emission. The method was also successfully applied to the nitrification of p-xylene, toluene, and chlorobenzene with good yields.
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Affiliation(s)
- Qiao Song
- Department of Chemistry, Xihua University, Chengdu 610039, China
- Asymmetric Synthesis and Chiral Technology Key Laboratory of Sichuan Province, Yibin 644000, China
- Correspondence: (Q.S.); (Z.W.)
| | - Xiangui Lei
- Department of Chemistry, Xihua University, Chengdu 610039, China
- Asymmetric Synthesis and Chiral Technology Key Laboratory of Sichuan Province, Yibin 644000, China
| | - Sheng Yang
- Department of Chemistry, Xihua University, Chengdu 610039, China
- Asymmetric Synthesis and Chiral Technology Key Laboratory of Sichuan Province, Yibin 644000, China
| | - Sheng Wang
- Department of Chemistry, Xihua University, Chengdu 610039, China
| | - Jianhui Wang
- Yinguang Group Sichuan North Hongguang Special Chemical Co., Ltd., Yibin 644000, China
| | - Jiujun Chen
- Yinguang Group Sichuan North Hongguang Special Chemical Co., Ltd., Yibin 644000, China
| | - Yong Xiang
- Yinguang Group Sichuan North Hongguang Special Chemical Co., Ltd., Yibin 644000, China
| | - Qingwu Huang
- Yinguang Group Sichuan North Hongguang Special Chemical Co., Ltd., Yibin 644000, China
| | - Zhouyu Wang
- Department of Chemistry, Xihua University, Chengdu 610039, China
- Yinguang Group Sichuan North Hongguang Special Chemical Co., Ltd., Yibin 644000, China
- Correspondence: (Q.S.); (Z.W.)
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Pompe N, Chen J, Illarionov B, Panter S, Fischer M, Bacher A, Weber S. Methyl groups matter: Photo-CIDNP characterizations of the semiquinone radicals of FMN and demethylated FMN analogs. J Chem Phys 2019; 151:235103. [PMID: 31864274 DOI: 10.1063/1.5130557] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In this contribution, the relative hyperfine couplings are determined for the 1H nuclei of the flavin mononucleotide (FMN) radical in an aqueous environment. In addition, three structural analogs with different methylation patterns are characterized and the influence of the substituents at the isoalloxazine moiety on the electronic structure of the radicals is explored. By exploiting nuclear hyperpolarization generated via the photo-CIDNP (chemically induced dynamic nuclear polarization) effect, it is possible to study the short-lived radical species generated by in situ light excitation. Experimental data are extracted by least-squares fitting and supported by quantum chemical calculations and published values from electron paramagnetic resonance and electron-nuclear double resonance. Furthermore, mechanistic details of the photoreaction of the investigated flavin analogs with l-tryptophan are derived from the photo-CIDNP spectra recorded at different pH values. Thereby, the neutral and anionic radicals of FMN and three structural analogs are, for the first time, characterized in terms of their electronic structure in an aqueous environment.
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Affiliation(s)
- Nils Pompe
- Institute of Physical Chemistry, University of Freiburg, 79104 Freiburg, Germany
| | - Jing Chen
- Institute of Physical Chemistry, University of Freiburg, 79104 Freiburg, Germany
| | - Boris Illarionov
- Hamburg School of Food Science, Institute of Food Chemistry, University of Hamburg, 20146 Hamburg, Germany
| | - Sabrina Panter
- Institute of Physical Chemistry, University of Freiburg, 79104 Freiburg, Germany
| | - Markus Fischer
- Hamburg School of Food Science, Institute of Food Chemistry, University of Hamburg, 20146 Hamburg, Germany
| | - Adelbert Bacher
- Department of Chemistry, Technical University of Munich, 85748 Garching, Germany
| | - Stefan Weber
- Institute of Physical Chemistry, University of Freiburg, 79104 Freiburg, Germany
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Thibodeaux CJ, Chang WC, Liu HW. Unraveling flavoenzyme reaction mechanisms using flavin analogues and linear free energy relationships. Methods Enzymol 2019; 620:167-188. [DOI: 10.1016/bs.mie.2019.03.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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