301
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Yoshioka E, Kohtani S, Jichu T, Fukazawa T, Nagai T, Kawashima A, Takemoto Y, Miyabe H. Aqueous-Medium Carbon-Carbon Bond-Forming Radical Reactions Catalyzed by Excited Rhodamine B as a Metal-Free Organic Dye under Visible Light Irradiation. J Org Chem 2016; 81:7217-29. [PMID: 27314306 DOI: 10.1021/acs.joc.6b01102] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The utility of rhodamine B as a water-soluble organic photocatalyst was studied in the cascade radical addition-cyclization-trapping reactions under visible light irradiation. In the presence of (i-Pr)2NEt, the electron transfer from the excited rhodamine B to perfluoroalkyl iodides proceeded smoothly to promote the carbon-carbon bond-forming radical reactions in aqueous media. When i-C3F7I was employed as a radical precursor, the aqueous-medium radical reactions proceeded even in the absence of (i-Pr)2NEt. In these reactions, the direct electron transfer from the excited singlet state of rhodamine B would take place. Furthermore, the cleavage of the C-I bond in less reactive i-PrI could be achieved by the reductive electron transfer from the excited rhodamine B, which was confirmed by the fluorescence quenching of rhodamine B with the addition of i-PrI.
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Affiliation(s)
- Eito Yoshioka
- School of Pharmacy, Hyogo University of Health Sciences , Minatojima, Chuo-ku, Kobe, 650-8530, Japan
| | - Shigeru Kohtani
- School of Pharmacy, Hyogo University of Health Sciences , Minatojima, Chuo-ku, Kobe, 650-8530, Japan
| | - Takahisa Jichu
- School of Pharmacy, Hyogo University of Health Sciences , Minatojima, Chuo-ku, Kobe, 650-8530, Japan
| | - Takuya Fukazawa
- School of Pharmacy, Hyogo University of Health Sciences , Minatojima, Chuo-ku, Kobe, 650-8530, Japan
| | - Toyokazu Nagai
- School of Pharmacy, Hyogo University of Health Sciences , Minatojima, Chuo-ku, Kobe, 650-8530, Japan
| | - Akira Kawashima
- School of Pharmacy, Hyogo University of Health Sciences , Minatojima, Chuo-ku, Kobe, 650-8530, Japan
| | - Yoshiji Takemoto
- Graduate School of Pharmaceutical Sciences, Kyoto University , Yoshida, Sakyo-ku, Kyoto 606-8501, Japan
| | - Hideto Miyabe
- School of Pharmacy, Hyogo University of Health Sciences , Minatojima, Chuo-ku, Kobe, 650-8530, Japan
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302
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Davies J, Svejstrup TD, Fernandez Reina D, Sheikh NS, Leonori D. Visible-Light-Mediated Synthesis of Amidyl Radicals: Transition-Metal-Free Hydroamination and N-Arylation Reactions. J Am Chem Soc 2016; 138:8092-5. [DOI: 10.1021/jacs.6b04920] [Citation(s) in RCA: 225] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Jacob Davies
- School
of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Thomas D. Svejstrup
- School
of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | | | - Nadeem S. Sheikh
- Department
of Chemistry, Faculty of Science, King Faisal University, Al-Ahsa 31982, Saudi Arabia
| | - Daniele Leonori
- School
of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K
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303
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Shen X, Harms K, Marsch M, Meggers E. A Rhodium Catalyst Superior to Iridium Congeners for Enantioselective Radical Amination Activated by Visible Light. Chemistry 2016; 22:9102-5. [DOI: 10.1002/chem.201601572] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Indexed: 12/12/2022]
Affiliation(s)
- Xiaodong Shen
- Fachbereich Chemie; Philipps-Universität Marburg; Hans-Meerwein-Straße 4 35043 Marburg Germany
| | - Klaus Harms
- Fachbereich Chemie; Philipps-Universität Marburg; Hans-Meerwein-Straße 4 35043 Marburg Germany
| | - Michael Marsch
- Fachbereich Chemie; Philipps-Universität Marburg; Hans-Meerwein-Straße 4 35043 Marburg Germany
| | - Eric Meggers
- Fachbereich Chemie; Philipps-Universität Marburg; Hans-Meerwein-Straße 4 35043 Marburg Germany
- College of Chemistry and Chemical Engineering; Xiamen University; Xiamen 361005 P. R. China
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304
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Walton JC. Synthetic Strategies for 5- and 6-Membered Ring Azaheterocycles Facilitated by Iminyl Radicals. Molecules 2016; 21:molecules21050660. [PMID: 27213311 PMCID: PMC6273063 DOI: 10.3390/molecules21050660] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 05/11/2016] [Accepted: 05/16/2016] [Indexed: 01/09/2023] Open
Abstract
The totality of chemical space is so immense that only a small fraction can ever be explored. Computational searching has indicated that bioactivity is associated with a comparatively small number of ring-containing structures. Pyrrole, indole, pyridine, quinoline, quinazoline and related 6-membered ring-containing aza-arenes figure prominently. This review focuses on the search for fast, efficient and environmentally friendly preparative methods for these rings with specific emphasis on iminyl radical-mediated procedures. Oxime derivatives, particularly oxime esters and oxime ethers, are attractive precursors for these radicals. Their use is described in conventional thermolytic, microwave-assisted and UV-vis based preparative procedures. Photoredox-catalyzed protocols involving designer oxime ethers are also covered. Choice can be made amongst these synthetic strategies for a wide variety of 5- and 6-membered ring heterocycles including phenanthridine and related aza-arenes. Applications to selected natural products and bioactive molecules, including trispheridine, vasconine, luotonin A and rutaecarpine, are included.
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Affiliation(s)
- John C Walton
- University of St. Andrews, EaStCHEM School of Chemistry, St. Andrews, Fife KY16 9ST, UK.
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305
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Xiong T, Zhang Q. New amination strategies based on nitrogen-centered radical chemistry. Chem Soc Rev 2016; 45:3069-87. [PMID: 27116936 DOI: 10.1039/c5cs00852b] [Citation(s) in RCA: 462] [Impact Index Per Article: 57.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The interesting and diverse biological activities of nitrogen-containing compounds make the construction of the C-N bond of great importance. Despite the tremendous advances that have been made in this research field, C-N bond formation based on nitrogen-centered radicals remains a significant challenge due to the harsh conditions required for the generation of nitrogen-centered radicals and their propensity for hydrogen abstraction or engaging in other degradation pathways. In the past several years, novel methodologies for C-N bond constructions based on nitrogen centered-radical intermediates, coordinated with metal or generated in the presence of visible-light and a photocatalyst, have attracted considerable attention. This tutorial review will summarize the significant progress of these efficient and mild radical amination reactions, with an emphasis on approaches for the generation of nitrogen-centered radicals and their reaction patterns, related mechanisms and synthetic applications, as well as unmet challenges in this emerging and promising field.
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Affiliation(s)
- Tao Xiong
- Department of Chemistry, Northeast Normal University, Changchun, 130024, China.
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306
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Liu H, Zhao L, Yuan Y, Xu Z, Chen K, Qiu S, Tan H. Potassium Thioacids Mediated Selective Amide and Peptide Constructions Enabled by Visible Light Photoredox Catalysis. ACS Catal 2016. [DOI: 10.1021/acscatal.5b02943] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Hongxin Liu
- Program
for Natural Product Chemical Biology, Key Laboratory Plant Resources
Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- State
Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial
Key Laboratory of Microbial Culture Collection and Application, Guangdong
Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangzhou 510070, China
| | - Liyun Zhao
- Program
for Natural Product Chemical Biology, Key Laboratory Plant Resources
Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Yunfei Yuan
- Program
for Natural Product Chemical Biology, Key Laboratory Plant Resources
Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Zhifang Xu
- Program
for Natural Product Chemical Biology, Key Laboratory Plant Resources
Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Kai Chen
- School
of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China
| | - Shengxiang Qiu
- Program
for Natural Product Chemical Biology, Key Laboratory Plant Resources
Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Haibo Tan
- Program
for Natural Product Chemical Biology, Key Laboratory Plant Resources
Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
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307
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Chen JR, Hu XQ, Lu LQ, Xiao WJ. Visible light photoredox-controlled reactions of N-radicals and radical ions. Chem Soc Rev 2016; 45:2044-56. [PMID: 26839142 DOI: 10.1039/c5cs00655d] [Citation(s) in RCA: 836] [Impact Index Per Article: 104.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Radicals are an important class of versatile and highly reactive species. Compared with the wide applications of various C-centred radicals, however, the N-radical species including N-centred radicals and radical ions remain largely unexplored due to the lack of convenient methods for their generation. In recent years, visible light photoredox catalysis has emerged as a powerful platform for the generation of various N-radical species and methodology development towards the synthesis of diverse N-containing compounds. In this tutorial review, we highlight recent advances in this rapidly developing area with particular emphases put on the working models and new reaction design.
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Affiliation(s)
- Jia-Rong Chen
- CCNU-uOttawa Joint Research Centre, Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei 430079, China.
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308
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Race NJ, Faulkner A, Shaw MH, Bower JF. Dichotomous mechanistic behavior in Narasaka-Heck cyclizations: electron rich Pd-catalysts generate iminyl radicals. Chem Sci 2016; 7:1508-1513. [PMID: 29899895 PMCID: PMC5963672 DOI: 10.1039/c5sc04037j] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 11/17/2015] [Indexed: 12/21/2022] Open
Abstract
Pd-catalyzed cyclizations of oxime esters with pendant alkenes are subject to an unusual ligand controlled mechanistic divergence. Pd-systems modified with electron deficient phosphines (e.g. P(3,5-(CF3)2C6H3)3) promote efficient aza-Heck cyclization, wherein C-N bond formation occurs via alkene imino-palladation. Conversely, electron rich ligands, such as P(t-Bu)3, cause deviation to a SET pathway and, in these cases, C-N bond formation occurs via cyclization of an iminyl radical. A series of mechanistic experiments differentiate the two pathways and the scope of the hybrid organometallic radical cyclization is outlined. This study represents a rare example in Pd-catalysis where selection between dichotomous mechanistic manifolds is facilitated solely by choice of phosphine ligand.
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Affiliation(s)
- Nicholas J Race
- School of Chemistry , University of Bristol , Bristol , BS8 1TS , UK .
| | - Adele Faulkner
- School of Chemistry , University of Bristol , Bristol , BS8 1TS , UK .
| | - Megan H Shaw
- School of Chemistry , University of Bristol , Bristol , BS8 1TS , UK .
| | - John F Bower
- School of Chemistry , University of Bristol , Bristol , BS8 1TS , UK .
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309
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Lima CGS, de M. Lima T, Duarte M, Jurberg ID, Paixão MW. Organic Synthesis Enabled by Light-Irradiation of EDA Complexes: Theoretical Background and Synthetic Applications. ACS Catal 2016. [DOI: 10.1021/acscatal.5b02386] [Citation(s) in RCA: 349] [Impact Index Per Article: 43.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | | | - Marcelo Duarte
- Institute of Chemistry, State University of Campinas, 13083-970, C.P. 6154, Campinas, São Paulo, Brazil
| | - Igor D. Jurberg
- Institute of Chemistry, State University of Campinas, 13083-970, C.P. 6154, Campinas, São Paulo, Brazil
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310
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Walton JC. Functionalised Oximes: Emergent Precursors for Carbon-, Nitrogen- and Oxygen-Centred Radicals. Molecules 2016; 21:63. [PMID: 26751437 PMCID: PMC6273297 DOI: 10.3390/molecules21010063] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 12/29/2015] [Accepted: 12/30/2015] [Indexed: 11/16/2022] Open
Abstract
Oxime derivatives are easily made, are non-hazardous and have long shelf lives. They contain weak N-O bonds that undergo homolytic scission, on appropriate thermal or photochemical stimulus, to initially release a pair of N- and O-centred radicals. This article reviews the use of these precursors for studying the structures, reactions and kinetics of the released radicals. Two classes have been exploited for radical generation; one comprises carbonyl oximes, principally oxime esters and amides, and the second comprises oxime ethers. Both classes release an iminyl radical together with an equal amount of a second oxygen-centred radical. The O-centred radicals derived from carbonyl oximes decarboxylate giving access to a variety of carbon-centred and nitrogen-centred species. Methods developed for homolytically dissociating the oxime derivatives include UV irradiation, conventional thermal and microwave heating. Photoredox catalytic methods succeed well with specially functionalised oximes and this aspect is also reviewed. Attention is also drawn to the key contributions made by EPR spectroscopy, aided by DFT computations, in elucidating the structures and dynamics of the transient intermediates.
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Affiliation(s)
- John C Walton
- EaStCHEM School of Chemistry, University of St. Andrews, St. Andrews, Fife KY16 9ST, UK.
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311
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Brueckner AC, Hancock EN, Anders EJ, Tierney MM, Morgan HR, Scott KA, Lamar AA. Visible-light-mediated, nitrogen-centered radical amination of tertiary alkyl halides under metal-free conditions to form α-tertiary amines. Org Biomol Chem 2016; 14:4387-92. [DOI: 10.1039/c6ob00616g] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A mild and operationally convenient amino-functionalization of a range of tertiary alkyl halides that involves a N,N-diiodosulfonamide reactive species has been developed.
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Affiliation(s)
| | | | | | | | - Heather R. Morgan
- Department of Chemistry and Biochemistry
- The University of Tulsa
- Tulsa
- USA
| | - Kristina A. Scott
- Department of Chemistry and Biochemistry
- The University of Tulsa
- Tulsa
- USA
| | - Angus A. Lamar
- Department of Chemistry and Biochemistry
- The University of Tulsa
- Tulsa
- USA
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312
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Zhang MJ, Schroeder GM, He YH, Guan Z. Visible light-mediated decarboxylative amination of indoline-2-carboxylic acids catalyzed by Rose Bengal. RSC Adv 2016. [DOI: 10.1039/c6ra17524d] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A visible-light-induced decarboxylative amination of N-protected indoline-2-carboxylic acids and azodicarboxylate esters catalyzed by Rose Bengal has been developed.
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Affiliation(s)
- Meng-Jie Zhang
- Key Laboratory of Applied Chemistry of Chongqing Municipality
- School of Chemistry and Chemical Engineering
- Southwest University
- Chongqing 400715
- PR China
| | | | - Yan-Hong He
- Key Laboratory of Applied Chemistry of Chongqing Municipality
- School of Chemistry and Chemical Engineering
- Southwest University
- Chongqing 400715
- PR China
| | - Zhi Guan
- Key Laboratory of Applied Chemistry of Chongqing Municipality
- School of Chemistry and Chemical Engineering
- Southwest University
- Chongqing 400715
- PR China
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313
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Koike T, Akita M. A versatile strategy for difunctionalization of carbon–carbon multiple bonds by photoredox catalysis. Org Chem Front 2016. [DOI: 10.1039/c6qo00139d] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photoredox catalysis is a versatile strategy for difunctionalization of carbon–carbon multiple bonds.
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Affiliation(s)
- Takashi Koike
- Laboratory for Chemistry and Life Science
- Institute of Innovative Research
- Tokyo Institute of Technology
- Yokohama
- Japan
| | - Munetaka Akita
- Laboratory for Chemistry and Life Science
- Institute of Innovative Research
- Tokyo Institute of Technology
- Yokohama
- Japan
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314
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Zhao QQ, Hu XQ, Yang MN, Chen JR, Xiao WJ. A visible-light photocatalytic N-radical cascade of hydrazones for the synthesis of dihydropyrazole-fused benzosultams. Chem Commun (Camb) 2016; 52:12749-12752. [DOI: 10.1039/c6cc05897c] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
An efficient N-centred radical 5-exo cyclization/addition/aromatization cascade by cooperative visible light photoredox and cobalt catalysis is described, giving dihydropyrazole-fused benzosultams in satisfactory yields.
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Affiliation(s)
- Quan-Qing Zhao
- CCNU-uOttawa Joint Research Centre
- Key Laboratory of Pesticide & Chemical Biology
- Ministry of Education
- College of Chemistry
- Central China Normal University
| | - Xiao-Qiang Hu
- CCNU-uOttawa Joint Research Centre
- Key Laboratory of Pesticide & Chemical Biology
- Ministry of Education
- College of Chemistry
- Central China Normal University
| | - Meng-Nan Yang
- CCNU-uOttawa Joint Research Centre
- Key Laboratory of Pesticide & Chemical Biology
- Ministry of Education
- College of Chemistry
- Central China Normal University
| | - Jia-Rong Chen
- CCNU-uOttawa Joint Research Centre
- Key Laboratory of Pesticide & Chemical Biology
- Ministry of Education
- College of Chemistry
- Central China Normal University
| | - Wen-Jing Xiao
- CCNU-uOttawa Joint Research Centre
- Key Laboratory of Pesticide & Chemical Biology
- Ministry of Education
- College of Chemistry
- Central China Normal University
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