1
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He J, Li X, He Q, Fan R. Cascade alkyl migration in 2-alkynylanilines for the synthesis of benzenoid ring multi-functionalized indoles. Chem Commun (Camb) 2023; 60:71-74. [PMID: 38018450 DOI: 10.1039/d3cc04815b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2023]
Abstract
Cascade alkyl migration of 2-alkynylanilines via an aromaticity destruction and reconstruction process is reported. The first alkyl migration is triggered by generation of a dearomatized arenium species via oxidation and cyclization, and the second is driven by the force to restore the aromaticity of rearrangement products. The reaction gave rise to a range of multi-functionalized indoles.
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Affiliation(s)
- Jiwen He
- Department of Chemistry, Fudan University, 2005 Songhu Road, Shanghai 200438, China.
| | - Xiaohua Li
- Department of Chemistry, Fudan University, 2005 Songhu Road, Shanghai 200438, China.
| | - Qiuqin He
- Department of Chemistry, Fudan University, 2005 Songhu Road, Shanghai 200438, China.
| | - Renhua Fan
- Department of Chemistry, Fudan University, 2005 Songhu Road, Shanghai 200438, China.
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2
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Huang JQ, Yu M, Yong X, Ho CY. NHC-Ni(II)-catalyzed cyclopropene-isocyanide [5 + 1] benzannulation. Nat Commun 2022; 13:4145. [PMID: 35842422 PMCID: PMC9288548 DOI: 10.1038/s41467-022-31896-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 07/08/2022] [Indexed: 11/17/2022] Open
Abstract
Isocyanides are common compounds in fine and bulk chemical syntheses. However, the direct addition of isocyanide to simple unactivated cyclopropene via transition metal catalysis is challenging. Most of the current approaches focus on 1,1-insertion of isocyanide to M-R or nucleophilc insertion. That is often complicated by the competitive homo-oligomerization reactivity occurring at room temperature, such as isocyanide 1,1-insertion by Ni(II). Here we show a (N-heterocyclic carbene)Ni(II) catalyst that enables cyclopropene-isocyanide [5 + 1] benzannulation. As shown in the broad substrate scope and a [trans-(N-heterocyclic carbene)Ni(isocyanide)Br2] crystal structure, the desired cross-reactivity is cooperatively controlled by the high reactivity of the cyclopropene, the sterically bulky N-heterocyclic carbene, and the strong coordination ability of the isocyanide. This direct addition strategy offers aromatic amine derivatives and complements the Dötz benzannulation and Semmelhack/Wulff 1,4-hydroquinone synthesis. Several sterically bulky, fused, and multi-substituted anilines and unsymmetric functionalized spiro-ring structures are prepared from those easily accessible starting materials expediently. The direct addition of isocyanides to cyclopropenes is challenging. Here, the authors report a catalytic cyclopropene-isocyanide [5 + 1] benzannulation catalyzed by an (N-heterocyclic carbene)Ni(II) complex; this method enables the preparation of fused and multi-substituted anilines and unsymmetrically functionalized spiro-ring structures.
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Affiliation(s)
- Jian-Qiang Huang
- Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen, 518055, China.
| | - Meng Yu
- Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen, 518055, China.,Shenzhen Grubbs Institute, Southern University of Science and Technology, Shenzhen, 518055, China.,Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Xuefeng Yong
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Chun-Yu Ho
- Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen, 518055, China. .,Shenzhen Grubbs Institute, Southern University of Science and Technology, Shenzhen, 518055, China. .,Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China.
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3
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Meerakrishna RS, Smile SS, Athira M, Choutipalli VSK, Shanmugam P. Diverse reactivity of isatin-based N, N′-cyclic azomethine imine dipoles with arynes: synthesis of 1′-methyl-2′-oxospiro [indene-1,3′-indolines] and 3-aryl-3-pyrazol-2-oxindoles. NEW J CHEM 2020. [DOI: 10.1039/d0nj01684e] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Reaction of aryne with isatin based N,N′-cyclic AMI 1,3-dipole afforded 3,3-disubstituted oxindole while methyl substitution on the pyrrolidine ring of 1,3-dipole directed [3+2] cycloaddition products.
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Affiliation(s)
| | - Suresh Snoxma Smile
- Organic and Bio-Organic Chemistry Division
- CSIR-Central Leather Research Institute (CLRI)
- Chennai-600020
- India
| | - Mohanakumaran Athira
- Organic and Bio-Organic Chemistry Division
- CSIR-Central Leather Research Institute (CLRI)
- Chennai-600020
- India
| | | | - Ponnusamy Shanmugam
- Organic and Bio-Organic Chemistry Division
- CSIR-Central Leather Research Institute (CLRI)
- Chennai-600020
- India
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4
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5
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Heravi MM, Kheilkordi Z, Zadsirjan V, Heydari M, Malmir M. Buchwald-Hartwig reaction: An overview. J Organomet Chem 2018. [DOI: 10.1016/j.jorganchem.2018.02.023] [Citation(s) in RCA: 118] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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6
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Meerakrishna RS, Athira M, Shanmugam P. Unusual [3+2] Spiroannulation and Creation of Stereogenic Quaternary Center at C‐3 of Oxindole via Addition of (Het)arynes to Isomerized Morita‐Baylis‐Hillman Adduct of Isatin. ChemistrySelect 2018. [DOI: 10.1002/slct.201702356] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
| | - Mohanakumaran Athira
- Organic and Bio Organic Chemistry DivisionCSIR-Central Leather Research Institute (CLRI), Adyar Chennai- 600020 INDIA
| | - Ponnusamy Shanmugam
- Organic and Bio Organic Chemistry DivisionCSIR-Central Leather Research Institute (CLRI), Adyar Chennai- 600020 INDIA
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7
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Lin JB, Shah TK, Goetz AE, Garg NK, Houk KN. Conjugated Trimeric Scaffolds Accessible from Indolyne Cyclotrimerizations: Synthesis, Structures, and Electronic Properties. J Am Chem Soc 2017; 139:10447-10455. [DOI: 10.1021/jacs.7b05317] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Janice B. Lin
- Department of Chemistry
and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Tejas K. Shah
- Department of Chemistry
and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Adam E. Goetz
- Department of Chemistry
and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Neil K. Garg
- Department of Chemistry
and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - K. N. Houk
- Department of Chemistry
and Biochemistry, University of California, Los Angeles, California 90095, United States
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California 90095, United States
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8
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Yao W, Zhang B, Li R, Jiang H, Chen X, Li F. A general and mild Cu-catalytic N-arylation of iminodibenzyls and iminostilbenes using unactivated aryl halides. RSC Adv 2017. [DOI: 10.1039/c7ra07437a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A ligand-free, highly efficient Cu-catalyticN-arylation of iminodibenzyl and iminostilbene derivatives with a broad scope of unactivated aryl halides under mild conditions has been developed for the first time.
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Affiliation(s)
| | | | | | | | | | - Fang Li
- Taizhou Univ
- Dept Chem
- PR China
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9
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Huang W, Buchwald SL. Palladium-Catalyzed N-Arylation of Iminodibenzyls and Iminostilbenes with Aryl- and Heteroaryl Halides. Chemistry 2016; 22:14186-9. [PMID: 27481439 DOI: 10.1002/chem.201603449] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Indexed: 11/08/2022]
Abstract
Compounds containing the iminodibenzyl and iminostilbene ring systems are prevalent in medicinal targets and functional materials. Herein, we report palladium-catalyzed conditions for the N-arylation of these ring systems. This protocol could be applied to a variety of (hetero)aryl chloride and bromide substrates, including ones, which are sterically hindered or those containing a variety of functional groups. Use of the fourth-generation palladacycle precatalyst gave good to excellent yields by using low palladium-catalyst loadings (0.1 to 1 mol %).
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Affiliation(s)
- Wenliang Huang
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA), Fax: (+1) 617 253-3297
| | - Stephen L Buchwald
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA), Fax: (+1) 617 253-3297.
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10
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Indole molecules as inhibitors of tubulin polymerization: potential new anticancer agents, an update (2013–2015). Future Med Chem 2016; 8:1291-316. [DOI: 10.4155/fmc-2016-0047] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Discovery of new indole-based tubulin polymerization inhibitors will continue to dominate the synthetic efforts of many medicinal chemists working in the field. The indole ring system is an essential part of several tubulin inhibitors identified in the recent years. The present review article will update the synthesis, anticancer and tubulin inhibition activities of several important new indole classes such as 2-phenylindoles (28, 29 & 30), oxindoles (35 & 38), indole-3-acrylamides (44), indolines (46), aroylindoles (49), carbozoles (75, 76 & 82), azacarbolines (87) and annulated indoles (100–105).
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11
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Medina JM, Jackl MK, Susick RB, Garg NK. Synthetic studies pertaining to the 2,3-pyridyne and 4,5-pyrimidyne. Tetrahedron 2016. [DOI: 10.1016/j.tet.2016.02.038] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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12
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Shah TK, Medina JM, Garg NK. Expanding the Strained Alkyne Toolbox: Generation and Utility of Oxygen-Containing Strained Alkynes. J Am Chem Soc 2016; 138:4948-54. [PMID: 26987257 DOI: 10.1021/jacs.6b01986] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report synthetic methodology that permits access to two oxacyclic strained intermediates, the 4,5-benzofuranyne and the 3,4-oxacyclohexyne. In situ trapping of these intermediates affords an array of heterocyclic scaffolds by the formation of one or more new C-C or C-heteroatom bonds. Experimentally determined regioselectivities were consistent with predictions made using the distortion/interaction model and were also found to be greater compared to selectivities seen in the case of trapping experiments of the corresponding N-containing intermediates. These studies demonstrate the synthetic versatility of oxacyclic arynes and alkynes for the synthesis of functionalized heterocycles, while further expanding the scope of the distortion/interaction model. Moreover, these efforts underscore the value of harnessing strained heterocyclic intermediates as a unique approach to building polycyclic heteroatom-containing frameworks.
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Affiliation(s)
- Tejas K Shah
- Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States
| | - Jose M Medina
- Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States
| | - Neil K Garg
- Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States
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13
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Chandrasoma N, Pathmanathan S, Buszek KR. A Practical, Multi-gram Synthesis of (±)-Herbindole A, (±)-Herbindole B, and (±)-Herbindole C from a Common Intermediate via 6,7-Indole Aryne Cycloaddition and Pd(0)-Catalyzed Cross-Coupling Reactions. Tetrahedron Lett 2015; 56:3507-3510. [PMID: 26516291 PMCID: PMC4620576 DOI: 10.1016/j.tetlet.2015.02.064] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A practical, multi-gram 10-step synthesis of racemic herbindole A, B, and C from a common intermediate is described. The key step features a remarkably regioselective C-7 metal-halogen exchange and elimination from a Bartoli-generated N-t-butyldimethylsilyl-4,6,7-tribromo-5-methylindole scaffold to afford the 6,7-indole aryne. Cycloaddition with cyclopentadiene, oxidative cleavage, and Fujimoto reduction gave a common intermediate from which all three herbindoles were readily derived. A final Pd(0)-catalyzed Negishi and Stille cross-coupling reaction at the C-4 bromide afforded each of the herbindoles on a multigram scale.
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Affiliation(s)
- Nalin Chandrasoma
- Department of Chemistry, University of Missouri, 205 Kenneth A. Spencer Chemical Laboratories, 5100 Rockhill Road, Kansas City, MO 64110
| | - Sivadarshini Pathmanathan
- Center of Excellence in Chemical Methodologies and Library Development (KU-CMLD), University of Kansas, Delbert M. Shankel Structural Biology Center, 2034 Becker Drive, Lawrence, KS 66047
| | - Keith R. Buszek
- Department of Chemistry, University of Missouri, 205 Kenneth A. Spencer Chemical Laboratories, 5100 Rockhill Road, Kansas City, MO 64110
- Center of Excellence in Chemical Methodologies and Library Development (KU-CMLD), University of Kansas, Delbert M. Shankel Structural Biology Center, 2034 Becker Drive, Lawrence, KS 66047
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14
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Rathi AK, Gawande MB, Zboril R, Varma RS. Microwave-assisted synthesis – Catalytic applications in aqueous media. Coord Chem Rev 2015. [DOI: 10.1016/j.ccr.2015.01.011] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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15
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Abstract
In 1989, the reaction of vinyl magnesium halides with ortho-substituted nitroarenes leading to indoles was discovered. This reaction is now frequently reported as the "Bartoli reaction" or the "Bartoli indole synthesis" (BIS). It has rapidly become the shortest and most flexible route to 7-substituted indoles, because the classical indole syntheses generally fail in their preparation. The flexibility of the Bartoli reaction is great as it can be extended to heteroaromatic nitro derivatives and can be run on solid support. This review will focus on the use of the Bartoli indole synthesis as the key step in preparations of complex indoles, which appeared in the literature in the last few years.
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Affiliation(s)
- Giuseppe Bartoli
- Dipartimento Chimica Industriale 'Toso Montanari', Università di Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy.
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16
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Goetz AE, Shah TK, Garg NK. Pyridynes and indolynes as building blocks for functionalized heterocycles and natural products. Chem Commun (Camb) 2015; 51:34-45. [DOI: 10.1039/c4cc06445c] [Citation(s) in RCA: 202] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
This feature article showcases the use of pyridynes and indolynes to construct functionalized heterocycles and complex natural products.
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Affiliation(s)
- Adam E. Goetz
- Department of Chemistry and Biochemistry
- University of California
- Los Angeles
- USA
| | - Tejas K. Shah
- Department of Chemistry and Biochemistry
- University of California
- Los Angeles
- USA
| | - Neil K. Garg
- Department of Chemistry and Biochemistry
- University of California
- Los Angeles
- USA
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17
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Abstract
Heterocyclic arynes have long been targeted as potential tools for the synthesis of substituted heterocycles. Recent advances have led to an improved understanding of the factors that determine regioselectivity in reactions of these strained intermediates and, in turn, the aryne distortion model. This paper highlights the use of this predictive model to enable the use of heterocyclic arynes, such as indolynes and pyridynes, in chemical synthesis.
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18
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Perchellet JPH, Perchellet EM, Singh CR, Monnett MT, Studer ER, Thornton PD, Brown N, Hill D, Neuenswander B, Lushington GH, Santini C, Buszek KR. Mechanisms by which synthetic 6,7-annulated-4-substituted indole compounds with anti-proliferative activity disrupt mitosis and block cytokinesis in human HL-60 tumor cells in vitro. Anticancer Res 2014; 34:1643-1655. [PMID: 24692693 PMCID: PMC4618554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
BACKGROUND Synthetic 6,7-annulated-4-substituted indole compounds, which elicit interesting antitumor effects in murine L1210 leukemia cells, were tested for their ability to inhibit human HL-60 tumor cell proliferation, disrupt mitosis and cytokinesis, and interfere with tubulin and actin polymerization in vitro. MATERIALS AND METHODS Various markers of metabolic activity, mitotic disruption and cytokinesis were used to assess the effectiveness of the drugs in the HL-60 tumor cell system. The ability of annulated indoles to alter the polymerizations of purified tubulin and actin were monitored in cell-free assays and were compared to the effects of drugs known to disrupt the dynamic structures of the mitotic spindle and cleavage furrow. RESULTS With one exception, annulated indoles inhibited the metabolic activity of HL-60 tumor cells in the low-micromolar range after two and four days in culture but these anti-proliferative effects were weaker than those of jasplakinolide, a known actin binder that blocks cytokinesis. After 24-48 h, antiproliferative concentrations of annulated indoles increased the mitotic index of HL-60 cells similarly to vincristine and stimulated the formation of many bi-nucleated cells, multi-nucleated cells and micronuclei, similarly to taxol and jasplakinolide, suggesting that these antitumor compounds might increase mitotic abnormality, induce chromosomal damage or missegregation, and block cytokinesis. Since annulated indoles mimicked the effect of vincristine on tubulin polymerization, but not that of taxol, these compounds might represent a new class of microtubule de-stabilizing agents that inhibit tubulin polymerization. Moreover, annulated indoles remarkably increased the rate and level of actin polymerization similarly to jasplakinolide, suggesting that they might also stabilize the cleavage furrow to block cytokinesis. CONCLUSION Although novel derivatives with different substitutions must be synthesized to elucidate structure-activity relationships, identify more potent antitumor compounds and investigate different molecular targets, annulated indoles appear to interact with both tubulin to reduce microtubule assembly and actin to block cytokinesis, thereby inducing bi- and multinucleation, resulting in genomic instability and apoptosis.
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Affiliation(s)
- Jean-Pierre H Perchellet
- Anti-Cancer Drug Laboratory, Kansas State University, Division of Biology, Ackert Hall, Manhattan, KS 66506-4901, U.S.A.
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19
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Nathel NFF, Shah TK, Bronner SM, Garg NK. Total syntheses of indolactam alkaloids (-)-indolactam V, (-)-pendolmycin, (-)-lyngbyatoxin A, and (-)-teleocidin A-2. Chem Sci 2014; 5:2184-2190. [PMID: 24839542 DOI: 10.1039/c4sc00256c] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We report the total syntheses of (-)-indolactam V and the C7-substituted indolactam alkaloids (-)-pendolmycin, (-)-lyngbyatoxin A, and (-)-teleocidin A-2. The strategy for preparing indolactam V relies on a distortion-controlled indolyne functionalization reaction to establish the C4-N linkage, in addition to an intramolecular conjugate addition to build the conformationally-flexible nine-membered ring. The total synthesis of indolactam V then sets the stage for the divergent synthesis of the other targeted alkaloids. Specifically, late-stage sp2-sp3 cross-couplings on an indolactam V derivative are used to introduce the key C7 substituents and the necessary quaternary carbons. These challenging couplings, in addition to other delicate manipulations, all proceed in the presence of a basic tertiary amine, an unprotected secondary amide, and an unprotected indole. Thus, our approach not only enables the enantiospecific total syntheses of four indolactam alkaloids, but also serves as a platform for probing complexity-generating and chemoselective transformations in the context of alkaloid total synthesis.
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Affiliation(s)
- Noah F Fine Nathel
- Department of Chemistry and Biochemistry, University of California, 607 Charles Young Drive East, Box 951569, Los Angeles, CA 90095, USA
| | - Tejas K Shah
- Department of Chemistry and Biochemistry, University of California, 607 Charles Young Drive East, Box 951569, Los Angeles, CA 90095, USA
| | - Sarah M Bronner
- Department of Chemistry and Biochemistry, University of California, 607 Charles Young Drive East, Box 951569, Los Angeles, CA 90095, USA
| | - Neil K Garg
- Department of Chemistry and Biochemistry, University of California, 607 Charles Young Drive East, Box 951569, Los Angeles, CA 90095, USA
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20
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Syntheses of 4-, 5-, 6-, and 7-substituted tryptamine derivatives and the use of a bromine atom as a protecting group. Tetrahedron Lett 2014. [DOI: 10.1016/j.tetlet.2013.12.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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21
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Crawford SM, Lavery CB, Stradiotto M. BippyPhos: a single ligand with unprecedented scope in the Buchwald-Hartwig amination of (hetero)aryl chlorides. Chemistry 2013; 19:16760-71. [PMID: 24281816 DOI: 10.1002/chem.201302453] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Indexed: 12/21/2022]
Abstract
Over the past two decades, considerable attention has been given to the development of new ligands for the palladium-catalyzed arylation of amines and related NH-containing substrates (i.e., Buchwald-Hartwig amination). The generation of structurally diverse ligands, by research groups in both academia and industry, has facilitated the accommodation of sterically and electronically divergent substrates including ammonia, hydrazine, amines, amides, and NH heterocycles. Despite these achievements, problems with catalyst generality persist and access to multiple ligands is necessary to accommodate all of these NH-containing substrates. In our quest to address this significant limitation we identified the BippyPhos/[Pd(cinnamyl)Cl]2 catalyst system as being capable of catalyzing the amination of a variety of functionalized (hetero)aryl chlorides, as well as bromides and tosylates, at moderate to low catalyst loadings. The successful transformations described herein include primary and secondary amines, NH heterocycles, amides, ammonia and hydrazine, thus demonstrating the largest scope in the NH-containing coupling partner reported for a single Pd/ligand catalyst system. We also established BippyPhos/[Pd(cinnamyl)Cl]2 as exhibiting the broadest demonstrated substrate scope for metal-catalyzed cross-coupling of (hetero)aryl chlorides with NH indoles. Furthermore, the remarkable ability of BippyPhos/[Pd(cinnamyl)Cl]2 to catalyze both the selective monoarylation of ammonia and the N-arylation of indoles was exploited in the development of a new one-pot, two-step synthesis of N-aryl heterocycles from ammonia, ortho-alkynylhalo(hetero)arenes and (hetero) aryl halides through tandem N-arylation/hydroamination reactions. Although the scope in the NH-containing coupling partner is broad, BippyPhos/[Pd(cinnamyl)Cl]2 also displays a marked selectivity profile that was exploited in the chemoselective monoarylation of substrates featuring two chemically distinct NH-containing moieties.
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Affiliation(s)
- Sarah M Crawford
- Department of Chemistry, Dalhousie University, 6274 Coburg Rd., P. O. Box 15000, Halifax, NS, B3H 4R2 (Canada)
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22
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Kaushik NK, Kaushik N, Attri P, Kumar N, Kim CH, Verma AK, Choi EH. Biomedical importance of indoles. Molecules 2013; 18:6620-62. [PMID: 23743888 PMCID: PMC6270133 DOI: 10.3390/molecules18066620] [Citation(s) in RCA: 826] [Impact Index Per Article: 75.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 05/27/2013] [Accepted: 05/28/2013] [Indexed: 11/16/2022] Open
Abstract
The indole nucleus is an important element of many natural and synthetic molecules with significant biological activity. This review covers some of the relevant and recent achievements in the biological, chemical and pharmacological activity of important indole derivatives in the areas of drug discovery and analysis.
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Affiliation(s)
- Nagendra Kumar Kaushik
- Plasma Bioscience Research Center, Kwangwoon University, Seoul 139701, Korea; E-Mails: (P.A.); (N.K.); (C.H.K.)
- Authors to whom correspondence should be addressed; E-Mails: (N.K.K); (N.K.); (A.K.V.); (E.H.C.); Tel.: +82-10-4187-8618 (N.K.K.) Fax: +82-940-5664 (N.K.K)
| | - Neha Kaushik
- Plasma Bioscience Research Center, Kwangwoon University, Seoul 139701, Korea; E-Mails: (P.A.); (N.K.); (C.H.K.)
- Authors to whom correspondence should be addressed; E-Mails: (N.K.K); (N.K.); (A.K.V.); (E.H.C.); Tel.: +82-10-4187-8618 (N.K.K.) Fax: +82-940-5664 (N.K.K)
| | - Pankaj Attri
- Plasma Bioscience Research Center, Kwangwoon University, Seoul 139701, Korea; E-Mails: (P.A.); (N.K.); (C.H.K.)
| | - Naresh Kumar
- Plasma Bioscience Research Center, Kwangwoon University, Seoul 139701, Korea; E-Mails: (P.A.); (N.K.); (C.H.K.)
| | - Chung Hyeok Kim
- Plasma Bioscience Research Center, Kwangwoon University, Seoul 139701, Korea; E-Mails: (P.A.); (N.K.); (C.H.K.)
| | - Akhilesh Kumar Verma
- Department of Chemistry, University of Delhi, Delhi 110007, India
- Authors to whom correspondence should be addressed; E-Mails: (N.K.K); (N.K.); (A.K.V.); (E.H.C.); Tel.: +82-10-4187-8618 (N.K.K.) Fax: +82-940-5664 (N.K.K)
| | - Eun Ha Choi
- Plasma Bioscience Research Center, Kwangwoon University, Seoul 139701, Korea; E-Mails: (P.A.); (N.K.); (C.H.K.)
- Authors to whom correspondence should be addressed; E-Mails: (N.K.K); (N.K.); (A.K.V.); (E.H.C.); Tel.: +82-10-4187-8618 (N.K.K.) Fax: +82-940-5664 (N.K.K)
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23
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Chandrasoma N, Brown N, Brassfield A, Nerurkar A, Suarez S, Buszek KR. Total Synthesis of (±)-Cis-Trikentrin B via Intermolecular 6,7-Indole Aryne Cycloaddition and Stille Cross-Coupling. Tetrahedron Lett 2013; 54:913-917. [PMID: 25278636 DOI: 10.1016/j.tetlet.2012.11.125] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
An efficient total synthesis of the annulated indole natural product (±)-cis-trikentrin B was accomplished by means of a regioselectively generated 6,7-indole aryne cycloaddition via selective metal-halogen exchange from a 5,6,7-tribromoindole. The unaffected C-5 bromine was subsequently used for a Stille cross-coupling to install the butenyl side chain and complete the synthesis. This strategy provides rapid access into the trikentrins and the related herbindoles, and represents another application of this methodology to natural products total synthesis. The required 5,6,7-indole aryne precursor was prepared using the Leimgruber-Batcho indole synthesis.
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Affiliation(s)
- Nalin Chandrasoma
- Department of Chemistry, University of Missouri, 205 Kenneth A. Spencer Chemical Laboratories, 5100 Rockhill Road, Kansas City, Missouri 64110, USA
| | - Neil Brown
- Department of Chemistry, University of Missouri, 205 Kenneth A. Spencer Chemical Laboratories, 5100 Rockhill Road, Kansas City, Missouri 64110, USA ; Center of Excellence in Chemical Methodologies and Library Development, University of Kansas, Del Shankel Structural Biology Center, 2034 Becker Drive, Lawrence, Kansas 66047, USA
| | - Allen Brassfield
- Department of Chemistry, University of Missouri, 205 Kenneth A. Spencer Chemical Laboratories, 5100 Rockhill Road, Kansas City, Missouri 64110, USA
| | - Alok Nerurkar
- Department of Chemistry, University of Missouri, 205 Kenneth A. Spencer Chemical Laboratories, 5100 Rockhill Road, Kansas City, Missouri 64110, USA
| | - Susana Suarez
- Department of Chemistry, University of Missouri, 205 Kenneth A. Spencer Chemical Laboratories, 5100 Rockhill Road, Kansas City, Missouri 64110, USA
| | - Keith R Buszek
- Department of Chemistry, University of Missouri, 205 Kenneth A. Spencer Chemical Laboratories, 5100 Rockhill Road, Kansas City, Missouri 64110, USA ; Center of Excellence in Chemical Methodologies and Library Development, University of Kansas, Del Shankel Structural Biology Center, 2034 Becker Drive, Lawrence, Kansas 66047, USA
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24
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Perchellet JPH, Waters AM, Perchellet EM, Thornton PD, Brown N, Hill D, Neuenswander B, Lushington GH, Santini C, Chandrasoma N, Buszek KR. Antitumor effects of synthetic 6,7-annulated-4-substituted indole compounds in L1210 leukemic cells in vitro. Anticancer Res 2012; 32:4671-4684. [PMID: 23155229 PMCID: PMC4175989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
BACKGROUND Because annulated indoles have almost no representation in the PubChem or MLSMR databases, an unprecedented class of an indole-based library was constructed, using the indole aryne methodology, and screened for antitumor activity. Sixty-six novel 6,7-annulated-4-substituted indole compounds were synthesized, using a strategic combination of 6,7-indolyne cycloaddition and cross-coupling reactions under both Suzuki-Miyaura and Buchwald-Hartwig conditions, and tested for their effectiveness against murine L1210 tumor cell proliferation in vitro. MATERIALS AND METHODS Various markers of tumor cell metabolism, DNA degradation, mitotic disruption, cytokinesis and apoptosis were assayed in vitro to evaluate drug cytotoxicity. RESULTS Most compounds inhibited the metabolic activity of leukemic cells in a time- and concentration-dependent manner but only 9 of them were sufficiently potent to inhibit L1210 tumor cell proliferation by 50% in the low-μM range after 2 (IC(50): 4.5-20.4 μM) and 4 days (0.5-4.0 μM) in culture. However, the antiproliferative compounds that were the most effective at day 4 were not necessarily the most potent at day 2, suggesting different speeds of action. A 3-h treatment with antiproliferative annulated indole was sufficient to inhibit, in a concentration-dependent manner, the rate of DNA synthesis measured in L1210 cells over a 0.5-h period of pulse-labeling with (3)H-thymidine. Four of the antiproliferative compounds had weak DNA-binding activities but one compound reduced the fluorescence of the ethidium bromide-DNA complex by up to 53%, suggesting that some annulated indoles might directly interact with double-stranded DNA to disrupt its integrity and prevent the dye from intercalating into DNA base pairs. However, all 9 antiproliferative compounds induced DNA cleavage at 24 h in L1210 cells, containing (3)H-thymidine-prelabeled DNA, suggesting that these antitumor annulated indoles might trigger an apoptotic pathway of DNA fragmentation. Indeed the antiproliferative annulated indoles caused a time-dependent increase of caspase-3 activity with a peak at 6 h. Interestingly, the compounds with the most potent antiproliferative IC(50) values at day 2 were consistently the most effective at inhibiting DNA synthesis at 3 h and inducing DNA fragmentation at 24 h. After 24-48 h, antiproliferative concentrations of annulated indoles increased the mitotic index of L1210 cells and stimulated the formation of many bi-nucleated cells, multi-nucleated cells, apoptotic cells and micronuclei, suggesting that these antitumor compounds might enhance mitotic abnormality, induce chromosomal damage or missegregation, and block cytokinesis to induce apoptosis. CONCLUSION Although annulated indoles may have interesting bioactivity, novel derivatives with different substitutions must be synthesized to elucidate structure-activity relationships, identify more potent antitumor lead compounds, and investigate their molecular targets and mechanisms of action.
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Affiliation(s)
- Jean-Pierre H Perchellet
- Anti-Cancer Drug Laboratory, Kansas State University, Division of Biology, Ackert Hall, Manhattan, KS 66506-4901, USA.
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25
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Brown N, Buszek KR. Regioselectivity of Diels-Alder Reactions Between 6,7-Dehydrobenzofuran and 2-Substituted Furans. Tetrahedron Lett 2012; 53:4022-4025. [PMID: 25278635 PMCID: PMC4179875 DOI: 10.1016/j.tetlet.2012.05.118] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We describe the first report of the generation of 6,7-dehydrobenzofuran (6,7-benzofuranyne) from 6,7-dihalobenzofurans via metal-halogen exchange and elimination, in a manner similar to our previous work with 6,7-indole arynes. This benzofuranyne undergoes highly regioselective Diels-Alder cycloadditions with 2-substituted furans.
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Affiliation(s)
- Neil Brown
- Department of Chemistry, University of Missouri-Kansas City, 205 Spencer Chemical Laboratories, 5100 Rockhill Road, Kansas City, MO, 64110, USA
- The University of Kansas Center of Excellence in Chemical Methodologies and Library Development, Structural Biology Center, 2121 Simons Drive, Lawrence, Kansas 66047, USA
| | - Keith R. Buszek
- Department of Chemistry, University of Missouri-Kansas City, 205 Spencer Chemical Laboratories, 5100 Rockhill Road, Kansas City, MO, 64110, USA
- The University of Kansas Center of Excellence in Chemical Methodologies and Library Development, Structural Biology Center, 2121 Simons Drive, Lawrence, Kansas 66047, USA
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26
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Goetz AE, Bronner SM, Cisneros JD, Melamed JM, Paton RS, Houk KN, Garg NK. An efficient computational model to predict the synthetic utility of heterocyclic arynes. Angew Chem Int Ed Engl 2012; 51:2758-62. [PMID: 22307724 PMCID: PMC4502420 DOI: 10.1002/anie.201108863] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Indexed: 11/08/2022]
Abstract
Think before you act: a computational approach is reported for evaluating the synthetic potential of heterocyclic arynes. Routine and rapid calculations of arene dehydrogenation energies and aryne angle distortion predict the likelihood that a given hetaryne can be generated, as well as the degree of regioselectivity expected in a reaction between a given hetaryne and a nucleophilic trapping agent.
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Affiliation(s)
- Adam E. Goetz
- Department of Chemistry and Biochemistry University of California, Los Angeles Los Angeles, CA 90095 (USA)
| | - Sarah M. Bronner
- Department of Chemistry and Biochemistry University of California, Los Angeles Los Angeles, CA 90095 (USA)
| | - Jordan D. Cisneros
- Department of Chemistry and Biochemistry University of California, Los Angeles Los Angeles, CA 90095 (USA)
| | - Joshua M. Melamed
- Department of Chemistry and Biochemistry University of California, Los Angeles Los Angeles, CA 90095 (USA)
| | - Robert S. Paton
- Department of Chemistry and Biochemistry University of California, Los Angeles Los Angeles, CA 90095 (USA)
- Chemistry Research Laboratory University of Oxford, Mansfield Road, Oxford OX1 3TA, UK
| | - K. N. Houk
- Department of Chemistry and Biochemistry University of California, Los Angeles Los Angeles, CA 90095 (USA)
| | - Neil K. Garg
- Department of Chemistry and Biochemistry University of California, Los Angeles Los Angeles, CA 90095 (USA)
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27
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Goetz AE, Bronner SM, Cisneros JD, Melamed JM, Paton RS, Houk KN, Garg NK. An Efficient Computational Model to Predict the Synthetic Utility of Heterocyclic Arynes. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201108863] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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28
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Jiang H, Pan X, Huang L, Zhao J, Shi D. Synthesis of 4H-cyclopenta[c]furans via cooperative PdCl2–FeCl2 catalyzed cascade cyclization reaction involving a novel acyl rearrangement process. Chem Commun (Camb) 2012; 48:4698-700. [DOI: 10.1039/c2cc31138k] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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29
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Huters AD, Quasdorf KW, Styduhar ED, Garg NK. Total synthesis of (-)-N-methylwelwitindolinone C isothiocyanate. J Am Chem Soc 2011; 133:15797-9. [PMID: 21819133 PMCID: PMC3188348 DOI: 10.1021/ja206538k] [Citation(s) in RCA: 122] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report the first total synthesis of (-)-N-methylwelwitindolinone C isothiocyanate. Our route features a number of key transformations, including an indolyne cyclization to assemble the [4.3.1]-bicyclic scaffold, as well as a late-stage intramolecular nitrene insertion to functionalize the C11 bridgehead carbon en route to the natural product.
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Affiliation(s)
- Alexander D. Huters
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095
| | - Kyle W. Quasdorf
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095
| | - Evan D. Styduhar
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095
| | - Neil K. Garg
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095
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