1
|
Choi H, Ham WS, van Bonn P, Zhang J, Kim D, Chang S. Mechanistic Approach Toward the C4-Selective Amination of Pyridines via Nucleophilic Substitution of Hydrogen. Angew Chem Int Ed Engl 2024; 63:e202401388. [PMID: 38589725 DOI: 10.1002/anie.202401388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 03/25/2024] [Accepted: 04/08/2024] [Indexed: 04/10/2024]
Abstract
The development of site-selective functionalization of N-heteroarenes is highly desirable in streamlined synthesis. In this context, direct amination of pyridines stands as an important synthetic methodology, with particular emphasis on accessing 4-aminopyridines, a versatile pharmacophore in medicinal chemistry. Herein, we report a reaction manifold for the C4-selective amination of pyridines by employing nucleophilic substitution of hydrogen (SNH). Through 4-pyridyl pyridinium salt intermediates, 4-aminopyridine products are obtained in reaction with aqueous ammonia without intermediate isolation. The notable regioselectivity was achieved by the electronic tuning of the external pyridine reagents along with the maximization of polarizability in the proton elimination stage. Further mechanistic investigations provided a guiding principle for the selective C-H pyridination of additional N-heteroarenes, presenting a strategic avenue for installation of diverse functional groups.
Collapse
Affiliation(s)
- Hoonchul Choi
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, South Korea
| | - Won Seok Ham
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, South Korea
| | - Pit van Bonn
- Institute of Organic Chemistry, RWTH Aachen University, Aachen, 52074, Germany
| | - Jianbo Zhang
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, South Korea
| | - Dongwook Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, South Korea
| | - Sukbok Chang
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, South Korea
| |
Collapse
|
2
|
Zasada A, Brześkiewicz J, Antoniak D, Bechcicka M, Loska R, Mąkosza M. Synthesis of quinoxaline derivatives via aromatic nucleophilic substitution of hydrogen. Org Biomol Chem 2023; 21:994-999. [PMID: 36515404 DOI: 10.1039/d2ob02016e] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The electrophilic nature of quinoxaline has been explored in the vicarious nucleophilic substitution (VNS) of hydrogen with various carbanions as nucleophiles in an attempt to develop a general method for functionalizing the heterocyclic ring. Only poorly stabilized nitrile carbanions were found to give the VNS products. 2-Chloroquinoxaline gave products of SNAr of chlorine preferentially. A variety of quinoxaline derivatives containing cyanoalkyl, sulfonylalkyl, benzyl or ester substituents, including fluorinated ones, have been prepared in the VNS reactions with quinoxaline N-oxide.
Collapse
Affiliation(s)
- Aleksandra Zasada
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland. .,Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Jakub Brześkiewicz
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
| | - Damian Antoniak
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland. .,Faculty of Chemistry, University of Warsaw, 02-093 Warsaw, Poland
| | - Małgorzata Bechcicka
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
| | - Rafał Loska
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
| | - Mieczysław Mąkosza
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
| |
Collapse
|
3
|
Bugaenko DI, Tikhanova OA, Karchava AV. Synthesis of Quinoline-2-thiones by Selective Deoxygenative C -H/C -S Functionalization of Quinoline N-Oxides with Thiourea. J Org Chem 2023; 88:1018-1023. [PMID: 36594585 DOI: 10.1021/acs.joc.2c02433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Quinoline-2-thiones valuable for synthetic and medicinal chemistry applications were obtained with excellent regioselectivity employing a deoxygenative C-H functionalization of readily available quinoline-N-oxides with thiourea upon activation with triflic anhydride. Unlike the current methods, this approach provides general access to diverse quinoline-2-thiones functionalized with groups of different electronic natures. Experimental simplicity and good to high yields are advantages of this protocol. Given the high reactivity of quinoline-2-thiones, this method provides an entry point for the synthesis of diverse organosulfur quinoline scaffolds.
Collapse
Affiliation(s)
- Dmitry I Bugaenko
- Department of Chemistry, Moscow State University, Moscow 119991, Russia
| | - Olga A Tikhanova
- Department of Chemistry, Moscow State University, Moscow 119991, Russia
| | | |
Collapse
|
4
|
Ham WS, Choi H, Zhang J, Kim D, Chang S. C2-Selective, Functional-Group-Divergent Amination of Pyrimidines by Enthalpy-Controlled Nucleophilic Functionalization. J Am Chem Soc 2022; 144:2885-2892. [PMID: 35138104 DOI: 10.1021/jacs.1c13373] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Synthesis of heteroaryl amines has been an important topic in organic chemistry because of their importance in small-molecule discovery. In particular, 2-aminopyrimidines represent a highly privileged structural motif that is prevalent in bioactive molecules, but a general strategy to introduce the pyrimidine C2-N bonds via direct functionalization is elusive. Here we describe a synthetic platform for site-selective C-H functionalization that affords pyrimidinyl iminium salt intermediates, which then can be transformed into various amine products in situ. Mechanism-based reagent design allowed for the C2-selective amination of pyrimidines, opening the new scope of site-selective heteroaryl C-H functionalization. Our method is compatible with a broad range of pyrimidines with sensitive functional groups and can access complex aminopyrimidines with high selectivity.
Collapse
Affiliation(s)
- Won Seok Ham
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, South Korea.,Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
| | - Hoonchul Choi
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, South Korea.,Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
| | - Jianbo Zhang
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, South Korea.,Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
| | - Dongwook Kim
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, South Korea.,Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
| | - Sukbok Chang
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, South Korea.,Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
| |
Collapse
|
5
|
Lipshultz JM, Radosevich AT. Uniting Amide Synthesis and Activation by P III/P V-Catalyzed Serial Condensation: Three-Component Assembly of 2-Amidopyridines. J Am Chem Soc 2021; 143:14487-14494. [PMID: 34478308 DOI: 10.1021/jacs.1c07608] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
An organophosphorus (PIII/PV redox) catalyzed method for the three-component condensation of amines, carboxylic acids, and pyridine N-oxides to generate 2-amidopyridines via serial dehydration is reported. Whereas amide synthesis and functionalization usually occur under divergent reaction conditions, here a phosphetane catalyst (together with a mild bromenium oxidant and terminal hydrosilane reductant) is shown to drive both steps chemoselectively in an auto-tandem catalytic cascade. The ability to both prepare and functionalize amides under the action of a single organocatalytic reactive intermediate enables new possibilities for the efficient and modular preparation of medicinal targets.
Collapse
Affiliation(s)
- Jeffrey M Lipshultz
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Alexander T Radosevich
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| |
Collapse
|
6
|
Bugaenko DI, Yurovskaya MA, Karchava AV. From Pyridine- N-oxides to 2-Functionalized Pyridines through Pyridyl Phosphonium Salts: An Umpolung Strategy. Org Lett 2021; 23:6099-6104. [PMID: 34269594 DOI: 10.1021/acs.orglett.1c02165] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The reactions of pyridine-N-oxides with Ph3P under the developed conditions provide an unprecedented route to (pyridine-2-yl)phosphonium salts. Upon activation with DABCO, these salts readily serve as functionalized 2-pyridyl nucleophile equivalents. This umpolung strategy allows for the selective C2 functionalization of the pyridine ring with electrophiles, avoiding the generation and use of unstable organometallic reagents. The protocol operates at ambient temperature and tolerates sensitive functional groups, enabling the synthesis of otherwise challenging compounds.
Collapse
Affiliation(s)
- Dmitry I Bugaenko
- Department of Chemistry, Moscow State University, Moscow 119992, Russia
| | | | | |
Collapse
|