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Xun W, Xu B, Chen B, Meng S, Chan ASC, Qiu FG, Zhao J. Regio and Enantioselective Organocatalytic Friedel-Crafts Alkylation of 4-Aminoindoles at the C7-Position. Org Lett 2018; 20:590-593. [PMID: 29341624 DOI: 10.1021/acs.orglett.7b03703] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A chiral phosphoric acid catalyzed highly regio- and enantioselective Friedel-Crafts alkylation at the indole C7-position was developed via the introduction of an alkylamine moiety at the C4-position of the indole ring. The methodology is applicable to a wide range of 4-aminoindoles and β,γ-unsaturated α-ketimino esters to furnish the corresponding C7-position functionalized chiral indole derivatives in high yields with moderate to excellent enantioselectivities. Furthermore, the α-ketimino ester moiety in the products is a versatile building block and enables many further transformations.
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Affiliation(s)
- Wen Xun
- Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences , Guangzhou 510530, P. R. China
| | - Bo Xu
- Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences , Guangzhou 510530, P. R. China
| | - Bo Chen
- Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences , Guangzhou 510530, P. R. China
| | - Shanshui Meng
- School of Pharmaceutical Sciences, Sun Yat-sen University , Guangzhou 510006, P. R. China
| | - Albert S C Chan
- School of Pharmaceutical Sciences, Sun Yat-sen University , Guangzhou 510006, P. R. China
| | - Fayang G Qiu
- Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences , Guangzhou 510530, P. R. China
| | - Junling Zhao
- School of Pharmaceutical Sciences, Sun Yat-sen University , Guangzhou 510006, P. R. China
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Nishio M, Umezawa Y, Fantini J, Weiss MS, Chakrabarti P. CH-π hydrogen bonds in biological macromolecules. Phys Chem Chem Phys 2015; 16:12648-83. [PMID: 24836323 DOI: 10.1039/c4cp00099d] [Citation(s) in RCA: 335] [Impact Index Per Article: 37.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This is a sequel to the previous Perspective "The CH-π hydrogen bond in chemistry. Conformation, supramolecules, optical resolution and interactions involving carbohydrates", which featured in a PCCP themed issue on "Weak Hydrogen Bonds - Strong Effects?": Phys. Chem. Chem. Phys., 2011, 13, 13873-13900. Evidence that weak hydrogen bonds play an enormously important role in chemistry and biochemistry has now accumulated to an extent that the rigid classical concept of hydrogen bonds formulated by Pauling needs to be seriously revised and extended. The concept of a more generalized hydrogen bond definition is indispensable for understanding the folding mechanisms of proteins. The CH-π hydrogen bond, a weak molecular force occurring between a soft acid CH and a soft base π-electron system, among all is one of the most important and plays a functional role in defining the conformation and stability of 3D structures as well as in many molecular recognition events. This concept is also valuable in structure-based drug design efforts. Despite their frequent occurrence in organic molecules and bio-molecules, the importance of CH-π hydrogen bonds is still largely unknown to many chemists and biochemists. Here we present a review that deals with the evidence, nature, characteristics and consequences of the CH-π hydrogen bond in biological macromolecules (proteins, nucleic acids, lipids and polysaccharides). It is hoped that the present Perspective will show the importance of CH-π hydrogen bonds and stimulate interest in the interactions of biological macromolecules, one of the most fascinating fields in bioorganic chemistry. Implication of this concept is enormous and valuable in the scientific community.
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Affiliation(s)
- Motohiro Nishio
- The CHPI Institute, 705-6-338, Minamioya, Machida-shi, Tokyo 194-0031, Japan.
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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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Evans LE, Cheeseman MD, Jones K. N-N bond-forming cyclization for the one-pot synthesis of N-aryl[3,4-d]pyrazolopyrimidines. Org Lett 2012; 14:3546-9. [PMID: 22734502 PMCID: PMC3390909 DOI: 10.1021/ol301561a] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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An efficient one-pot synthesis of N-aryl[3,4-d]pyrazolopyrimidines in good yield and under mild reaction conditions is described. By exploiting electron-deficient hydroxylamines, the substituted oxime products were formed with very high E-diastereoselectivity. The key step utilizes a cyclization reaction upon an oxime derived from hydroxylamine-O-sulfonic acid to form the N–N bond of the product.
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Affiliation(s)
- Lindsay E Evans
- Division of Cancer Therapeutics, The Institute of Cancer Research, 15 Cotswold Road, Sutton, Surrey SM2 5NG, UK
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Development of a new class of aromatase inhibitors: design, synthesis and inhibitory activity of 3-phenylchroman-4-one (isoflavanone) derivatives. Bioorg Med Chem 2012; 20:2603-13. [PMID: 22444875 DOI: 10.1016/j.bmc.2012.02.042] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2011] [Revised: 02/11/2012] [Accepted: 02/17/2012] [Indexed: 01/23/2023]
Abstract
Aromatase (CYP19) catalyzes the aromatization reaction of androgen substrates to estrogens, the last and rate-limiting step in estrogen biosynthesis. Inhibition of aromatase is a new and promising approach to treat hormone-dependent breast cancer. We present here the design and development of isoflavanone derivatives as potential aromatase inhibitors. Structural modifications were performed on the A and B rings of isoflavanones via microwave-assisted, gold-catalyzed annulation reactions of hydroxyaldehydes and alkynes. The in vitro aromatase inhibition of these compounds was determined by fluorescence-based assays utilizing recombinant human aromatase (baculovirus/insect cell-expressed). The compounds 3-(4-phenoxyphenyl)chroman-4-one (1h), 6-methoxy-3-phenylchroman-4-one (2a) and 3-(pyridin-3-yl)chroman-4-one (3b) exhibited potent inhibitory effects against aromatase with IC(50) values of 2.4 μM, 0.26 μM and 5.8 μM, respectively. Docking simulations were employed to investigate crucial enzyme/inhibitor interactions such as hydrophobic interactions, hydrogen bonding and heme iron coordination. This report provides useful information on aromatase inhibition and serves as a starting point for the development of new flavonoid aromatase inhibitors.
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Takahashi O, Kohno Y, Nishio M. Relevance of weak hydrogen bonds in the conformation of organic compounds and bioconjugates: evidence from recent experimental data and high-level ab initio MO calculations. Chem Rev 2011; 110:6049-76. [PMID: 20550180 DOI: 10.1021/cr100072x] [Citation(s) in RCA: 447] [Impact Index Per Article: 34.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Osamu Takahashi
- Department of Chemistry, Graduate School of Science, Hiroshima University, Kagamiyama, Higashi-Hiroshima, 739-8526, Japan.
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Jennings WB, McCarthy NJP, Kelly P, Malone JF. Topically resolved intramolecular CH-π interactions in phenylalanine derivatives. Org Biomol Chem 2009; 7:5156-62. [DOI: 10.1039/b916021n] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Endringer DC, Guimarães KG, Kondratyuk TP, Pezzuto JM, Braga FC. Selective inhibition of aromatase by a dihydroisocoumarin from Xyris pterygoblephara. JOURNAL OF NATURAL PRODUCTS 2008; 71:1082-4. [PMID: 18462007 PMCID: PMC2562161 DOI: 10.1021/np800098f] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Aromatase is a well-established target for the chemoprevention of breast cancer. The dihydroisocoumarin (3 R,4 R)-(-)-6-methoxy-1-oxo-3-pentyl-3,4-dihydro-1 H-isochromen-4-yl acetate (1) (IC 50 = 1.6 +/- 0.1 microM), isolated from aerial parts of Xyris pterygoblephara, showed aromatase inhibitory activity. The specificity of 1 was evaluated by inhibition assays with cytochrome P450 enzymes. CYP1A1 was inhibited modestly (IC 50 = 38.0 +/- 2.0 microM), while CYP2C8 and CYP3A4 enzymes were not affected. Dihydroisocoumarin 1 showed weak antiproliferative activity against MCF-7 (IC 50 = 66.9 +/- 2.3 microM) and LNCaP (IC 50 = 57.5 +/- 2.0 microM) cells and was inactive against LU-1 and HepG2 cells in culture. These results demonstrate the potential of dihydroisocoumarin 1 to serve as a selective aromatase inhibitor.
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Affiliation(s)
- Denise C. Endringer
- Faculdade de Farmácia, Universidade Federal de Minas Gerais. Av. Antonio Carlos, 6627
| | - Keller G. Guimarães
- Faculdade de Farmácia, Universidade Federal de Minas Gerais. Av. Antonio Carlos, 6627
| | - Tamara P. Kondratyuk
- CEP 31270-901, Belo Horizonte, Brazil and College of Pharmacy, University of Hawaii at Hilo, Hilo, Hawaii, USA 96720
| | - John M. Pezzuto
- CEP 31270-901, Belo Horizonte, Brazil and College of Pharmacy, University of Hawaii at Hilo, Hilo, Hawaii, USA 96720
| | - Fernão C. Braga
- Faculdade de Farmácia, Universidade Federal de Minas Gerais. Av. Antonio Carlos, 6627
- To whom correspondence should be addressed. Tel.: +5531 3409 6951; fax: +5531 3409 6935; e-mail: . E-mail address: (F.C. Braga)
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