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Ag 2O/squaramide cocatalyzed asymmetric interrupted Barton-Zard reaction of 8-nitroimidazo[1,2-a]pyridines. Sci Bull (Beijing) 2022; 67:1688-1695. [PMID: 36546048 DOI: 10.1016/j.scib.2022.07.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Revised: 07/02/2022] [Accepted: 07/13/2022] [Indexed: 01/07/2023]
Abstract
Imidazo[1,2-a]pyridines are present in numerous biologically active compounds as the core structural motif. Herein, we report an asymmetric interrupted Barton-Zard reaction of electron-deficient imidazo[1,2-a]pyridines with α-substituted isocyanoacetates. The reaction enables the dearomatization of 8-nitroimidazo[1,2-a]pyridines and hence offers straightforward access to an array of optically active highly functionalized imidazo[1,2-a]pyridine derivatives that possess three contiguous stereogenic centers in good yields (up to 98%) with high stereoselectivities (>19:1 dr, >99% ee). It is worth noting that the catalytic system consisting of a chiral squaramide and silver oxide displays remarkable reactivity and stereoselectivity, and a gram-scale reaction is compatible with the catalyst loading of 0.5 mol%. In addition, the synthetic potential of this method was showcased by versatile transformations of the product.
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Mikhailine AA, Morris RH. Effect of the structure of the diamine backbone of P-N-N-P ligands in iron(II) complexes on catalytic activity in the transfer hydrogenation of acetophenone. Inorg Chem 2010; 49:11039-44. [PMID: 21067160 DOI: 10.1021/ic101548j] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The asymmetric transfer hydrogenation of aromatic ketones can be efficiently accomplished using catalysts that are based on platinum group metals which are more toxic and less abundant than iron. For that reason the discovery of iron based catalysts for the use in this transformation is important. To address this issue, we synthesized a new series of iron(II)-based precatalysts trans-[Fe(Br)(CO)(PPh(2)CH(2)CH═NCHRCHRN═CHCH(2)PPh(2))]BPh(4) (5a-5d) containing P-N-N-P ligands with the diamines (R,R)-1,2-diaminocyclohexane (a), (R,R)-1,2-diphenyl-1,2-diaminoethane (b), (R,R)-1,2-di(4-methoxyphenyl)-1,2-diaminoethane (c), and ethylenediamine (d) incorporated in the backbone using a convenient one-pot synthesis using readily available starting materials. All of the complexes, when activated with a base, show a very high activity in the transfer hydrogenation catalysis of acetophenone, using 2-propanol as a reducing agent under mild conditions. A comparison of the TOF of complexes 5a-5d show that the catalytic activity of complexes increase as the size of the substituents in the backbone of ligands increases (d < a < b = c).
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Affiliation(s)
- Alexandre A Mikhailine
- Davenport Laboratory, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
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Palmer AM, Chiesa V, Schmid A, Münch G, Grobbel B, Zimmermann PJ, Brehm C, Buhr W, Simon WA, Kromer W, Postius S, Volz J, Hess D. Tetrahydrochromenoimidazoles as Potassium-Competitive Acid Blockers (P-CABs): Structure−Activity Relationship of Their Antisecretory Properties and Their Affinity toward the hERG Channel. J Med Chem 2010; 53:3645-74. [PMID: 20380432 DOI: 10.1021/jm100040c] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Andreas M. Palmer
- NYCOMED GmbH, Departments of Medicinal Chemistry, Biochemistry, Pharmacology, and Physicochemistry, Byk-Gulden-Strasse 2, D-78467 Konstanz, Germany
| | - Vittoria Chiesa
- NYCOMED GmbH, Departments of Medicinal Chemistry, Biochemistry, Pharmacology, and Physicochemistry, Byk-Gulden-Strasse 2, D-78467 Konstanz, Germany
| | - Anja Schmid
- NYCOMED GmbH, Departments of Medicinal Chemistry, Biochemistry, Pharmacology, and Physicochemistry, Byk-Gulden-Strasse 2, D-78467 Konstanz, Germany
| | - Gabriela Münch
- NYCOMED GmbH, Departments of Medicinal Chemistry, Biochemistry, Pharmacology, and Physicochemistry, Byk-Gulden-Strasse 2, D-78467 Konstanz, Germany
| | - Burkhard Grobbel
- NYCOMED GmbH, Departments of Medicinal Chemistry, Biochemistry, Pharmacology, and Physicochemistry, Byk-Gulden-Strasse 2, D-78467 Konstanz, Germany
| | - Peter J. Zimmermann
- NYCOMED GmbH, Departments of Medicinal Chemistry, Biochemistry, Pharmacology, and Physicochemistry, Byk-Gulden-Strasse 2, D-78467 Konstanz, Germany
| | - Christof Brehm
- NYCOMED GmbH, Departments of Medicinal Chemistry, Biochemistry, Pharmacology, and Physicochemistry, Byk-Gulden-Strasse 2, D-78467 Konstanz, Germany
| | - Wilm Buhr
- NYCOMED GmbH, Departments of Medicinal Chemistry, Biochemistry, Pharmacology, and Physicochemistry, Byk-Gulden-Strasse 2, D-78467 Konstanz, Germany
| | - Wolfgang-Alexander Simon
- NYCOMED GmbH, Departments of Medicinal Chemistry, Biochemistry, Pharmacology, and Physicochemistry, Byk-Gulden-Strasse 2, D-78467 Konstanz, Germany
| | - Wolfgang Kromer
- NYCOMED GmbH, Departments of Medicinal Chemistry, Biochemistry, Pharmacology, and Physicochemistry, Byk-Gulden-Strasse 2, D-78467 Konstanz, Germany
| | - Stefan Postius
- NYCOMED GmbH, Departments of Medicinal Chemistry, Biochemistry, Pharmacology, and Physicochemistry, Byk-Gulden-Strasse 2, D-78467 Konstanz, Germany
| | - Jürgen Volz
- NYCOMED GmbH, Departments of Medicinal Chemistry, Biochemistry, Pharmacology, and Physicochemistry, Byk-Gulden-Strasse 2, D-78467 Konstanz, Germany
| | - Dietmar Hess
- NMI TT GmbH, Markwiesenstrasse 55, D-72770 Reutlingen, Germany
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Palmer AM, Chrismann S, Münch G, Brehm C, Zimmermann PJ, Buhr W, Senn-Bilfinger J, Feth MP, Simon WA. Spiro(imidazo[1,2-a]pyrano[2,3-c]pyridine-9-indenes) as inhibitors of gastric acid secretion. Bioorg Med Chem 2009; 17:368-84. [DOI: 10.1016/j.bmc.2008.10.055] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2008] [Accepted: 10/23/2008] [Indexed: 01/14/2023]
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Palmer AM, Webel M, Scheufler C, Haag D, Müller B. Large-Scale Asymmetric Synthesis of the 3,6,7,8-Tetrahydrochromeno[7,8-d]imidazole BYK 405879: A Promising Candidate for the Treatment of Acid-Related Diseases. Org Process Res Dev 2008. [DOI: 10.1021/op800177x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Andreas M. Palmer
- NYCOMED GmbH, Department of Medicinal Chemistry and NYCOMED GmbH, Department of Process Chemistry Research, Byk-Gulden-Strasse 2, D-78467 Konstanz, Germany, and NYCOMED GmbH, Department of Process Chemistry Development, Robert-Bosch-Strasse 8, D-78224 Singen, Germany
| | - Matthias Webel
- NYCOMED GmbH, Department of Medicinal Chemistry and NYCOMED GmbH, Department of Process Chemistry Research, Byk-Gulden-Strasse 2, D-78467 Konstanz, Germany, and NYCOMED GmbH, Department of Process Chemistry Development, Robert-Bosch-Strasse 8, D-78224 Singen, Germany
| | - Christian Scheufler
- NYCOMED GmbH, Department of Medicinal Chemistry and NYCOMED GmbH, Department of Process Chemistry Research, Byk-Gulden-Strasse 2, D-78467 Konstanz, Germany, and NYCOMED GmbH, Department of Process Chemistry Development, Robert-Bosch-Strasse 8, D-78224 Singen, Germany
| | - Dieter Haag
- NYCOMED GmbH, Department of Medicinal Chemistry and NYCOMED GmbH, Department of Process Chemistry Research, Byk-Gulden-Strasse 2, D-78467 Konstanz, Germany, and NYCOMED GmbH, Department of Process Chemistry Development, Robert-Bosch-Strasse 8, D-78224 Singen, Germany
| | - Bernd Müller
- NYCOMED GmbH, Department of Medicinal Chemistry and NYCOMED GmbH, Department of Process Chemistry Research, Byk-Gulden-Strasse 2, D-78467 Konstanz, Germany, and NYCOMED GmbH, Department of Process Chemistry Development, Robert-Bosch-Strasse 8, D-78224 Singen, Germany
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