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Shaum JB, Nikolaev A, Steffens HC, Gonzalez L, Walker S, Samoshin AV, Hammersley G, La EH, Read de Alaniz J. Copper-Mediated Single-Electron Approach to Indoline Amination: Scope, Mechanism, and Total Synthesis of Asperazine A. J Org Chem 2022; 87:9907-9914. [PMID: 35876810 DOI: 10.1021/acs.joc.2c00923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pyrroloindolines bearing a C3-N linkage comprise the core of many biologically active natural products, but many methods toward their synthesis are limited by the sterics or electronics of the product. We report a single electron-based approach for the synthesis of this scaffold and demonstrate high-yielding aminations, regardless of electronic or steric demands. The transformation uses copper wire and isopropanol to promote the reaction. The broad synthetic utility of this heterogeneous copper-catalyzed approach to access pyrroloindolines, diketopiperazine, furoindoline, and (+)-asperazine is included, along with experiments to provide insight into the mechanism of this new process.
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Affiliation(s)
- James B Shaum
- Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California 93106, United States
| | - Andrei Nikolaev
- Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California 93106, United States
| | - Helena C Steffens
- Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California 93106, United States
| | - Luis Gonzalez
- Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California 93106, United States
| | - Shamon Walker
- Materials Department and Materials Research Laboratory, University of California at Santa Barbara, Santa Barbara, California 93106, United States
| | - Andrey V Samoshin
- Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California 93106, United States
| | - Gabrielle Hammersley
- Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California 93106, United States
| | - Ellia H La
- Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California 93106, United States
| | - Javier Read de Alaniz
- Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California 93106, United States
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Abstract
Low molecular weight, uncharged far-red and NIR dyes would be enabling for a range of imaging applications. Rational redesign of the coumarin scaffold leads to Fluoro-Coumarins (FCs), the lowest molecular weight dyes with emission maxima beyond 700, 800, and 900 nm. FCs display large Stokes shifts and high environmental sensitivity, with a 40-fold increase in emission intensity in hydrophobic solvents. Untargeted variants exhibit selective lipid droplet and nuclear staining in live cells. Furthermore, sulfo-lipid derivatization enables active targeting to the plasma membrane. Overall, these studies report a promising platform for the development of biocompatible, context-responsive imaging agents. Fluoro-Coumarins are a novel class of far-red and near-infrared solvent sensitive dyes of exceptionally low molecular weight.![]()
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Affiliation(s)
- Siddharth S Matikonda
- Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health Frederick Maryland 21702 USA
| | - Joseph Ivanic
- Advanced Biomedical Computational Science, Frederick National Laboratory for Cancer Research Frederick Maryland 21702 USA
| | - Miguel Gomez
- Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health Frederick Maryland 21702 USA
| | - Gabrielle Hammersley
- Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health Frederick Maryland 21702 USA
| | - Martin J Schnermann
- Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health Frederick Maryland 21702 USA
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Matikonda SS, Hammersley G, Kumari N, Grabenhorst L, Glembockyte V, Tinnefeld P, Ivanic J, Levitus M, Schnermann MJ. Impact of Cyanine Conformational Restraint in the Near-Infrared Range. J Org Chem 2020; 85:5907-5915. [PMID: 32275153 DOI: 10.1021/acs.joc.0c00236] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Appending conformationally restraining ring systems to the cyanine chromophore creates exceptionally bright fluorophores in the visible range. Here, we report the application of this strategy in the near-infrared range through the preparation of the first restrained heptamethine indocyanine. Time-resolved absorption spectroscopy and fluorescence correlation spectroscopy verify that, unlike the corresponding parent unrestrained variant, the restrained molecule is not subject to photoisomerization. Notably, however, the room-temperature emission efficiency and the fluorescence lifetime of the restrained cyanine are not extended relative to the parent cyanine, even in viscous solvents. Thus, in contrast to prior reports, the photoisomerization of heptamethine cyanines does not contribute significantly to the excited-state chemistry of these molecules. We also find that the fluorescence lifetime of the restrained heptamethine cyanine is temperature-insensitive and significantly extended at moderately elevated temperatures relative to the parent cyanine. Finally, computational studies have been used to evaluate the impact of the conformational restraint on atomic and orbital structure across the cyanine series. These studies clarify the role of photoisomerization in the heptamethine cyanine scaffold and demonstrate the dramatic effect of restraint on the temperature sensitivity of these dyes.
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Affiliation(s)
- Siddharth S Matikonda
- Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 376 Boyles Street, Frederick, Maryland 21702, United States
| | - Gabrielle Hammersley
- Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 376 Boyles Street, Frederick, Maryland 21702, United States
| | - Nikita Kumari
- School of Molecular Sciences and The Biodesign Institute at Arizona State University, Tempe, Arizona 85287, United States
| | - Lennart Grabenhorst
- Department of Chemistry and Center for NanoScience, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, München, 81377, Germany
| | - Viktorija Glembockyte
- Department of Chemistry and Center for NanoScience, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, München, 81377, Germany
| | - Philip Tinnefeld
- Department of Chemistry and Center for NanoScience, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, München, 81377, Germany
| | - Joseph Ivanic
- Advanced Biomedical Computational Science, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, United States
| | - Marcia Levitus
- School of Molecular Sciences and The Biodesign Institute at Arizona State University, Tempe, Arizona 85287, United States
| | - Martin J Schnermann
- Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 376 Boyles Street, Frederick, Maryland 21702, United States
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