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Abstract
The yields of ynamides using Hsung's second generation protocol depend substantially on the quality of K(3)PO(4). Samples of K(3)PO(4) from different suppliers were investigated by various techniques, revealing that the use of pure and anhydrous K(3)PO(4) provides higher ynamide yields in comparison to samples contaminated with hydrates (K(3)PO(4) x 1.5 H(2)O and K(3)PO(4) x 7 H(2)O). With high quality K(3)PO(4), a number of ynamides were synthesized in yields of 52-91%. In addition, we report that ynamides can undergo regioselective hydroamination with carbamates.
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Affiliation(s)
- Karin Dooleweerdt
- Department of Chemistry and the Interdisciplinary Nanoscience Center, University of Aarhus, Langelandsgade 140, 8000 Aarhus C, Denmark
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2
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Abstract
A catalyst, based on a biarylphosphine ligand, for the Pd-catalyzed cross-coupling reactions of amides and aryl mesylates is described. This system allows an array of aryl and heteroaryl mesylates to be transformed into the corresponding N-aryl amides in moderate to excellent yields.
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Affiliation(s)
- Karin Dooleweerdt
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Kramer S, Dooleweerdt K, Lindhardt AT, Rottländer M, Skrydstrup T. Highly Regioselective Au(I)-Catalyzed Hydroamination of Ynamides and Propiolic Acid Derivatives with Anilines. Org Lett 2009; 11:4208-11. [DOI: 10.1021/ol901565p] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Søren Kramer
- Center for Insoluble Protein Structures (inSPIN), Department of Chemistry and the Interdisciplinary Nanoscience Center, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark, and Division of Medicinal Chemistry, H. Lundbeck A/S, Ottiliavej 9, 2500 Valby, Denmark
| | - Karin Dooleweerdt
- Center for Insoluble Protein Structures (inSPIN), Department of Chemistry and the Interdisciplinary Nanoscience Center, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark, and Division of Medicinal Chemistry, H. Lundbeck A/S, Ottiliavej 9, 2500 Valby, Denmark
| | - Anders Thyboe Lindhardt
- Center for Insoluble Protein Structures (inSPIN), Department of Chemistry and the Interdisciplinary Nanoscience Center, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark, and Division of Medicinal Chemistry, H. Lundbeck A/S, Ottiliavej 9, 2500 Valby, Denmark
| | - Mario Rottländer
- Center for Insoluble Protein Structures (inSPIN), Department of Chemistry and the Interdisciplinary Nanoscience Center, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark, and Division of Medicinal Chemistry, H. Lundbeck A/S, Ottiliavej 9, 2500 Valby, Denmark
| | - Troels Skrydstrup
- Center for Insoluble Protein Structures (inSPIN), Department of Chemistry and the Interdisciplinary Nanoscience Center, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark, and Division of Medicinal Chemistry, H. Lundbeck A/S, Ottiliavej 9, 2500 Valby, Denmark
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Abstract
A catalyst based on a new biarylphosphine ligand (3) for the Pd-catalyzed cross-coupling reactions of amides and aryl chlorides is described. This system shows the highest turnover frequencies reported to date for these reactions, especially for aryl chloride substrates bearing an ortho substituent. An array of amides and aryl chlorides were successfully reacted in good to excellent yields.
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Affiliation(s)
- Brett P. Fors
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Karin Dooleweerdt
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Qingle Zeng
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Stephen L. Buchwald
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
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Affiliation(s)
- Karin Dooleweerdt
- Center for Insoluble Protein Structures (inSPIN), Department of Chemistry and the Interdisciplinary Nanoscience Center, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark, and H. Lundbeck A/S, Ottiliavej 9, 2400 Valby, Denmark
| | - Thomas Ruhland
- Center for Insoluble Protein Structures (inSPIN), Department of Chemistry and the Interdisciplinary Nanoscience Center, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark, and H. Lundbeck A/S, Ottiliavej 9, 2400 Valby, Denmark
| | - Troels Skrydstrup
- Center for Insoluble Protein Structures (inSPIN), Department of Chemistry and the Interdisciplinary Nanoscience Center, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark, and H. Lundbeck A/S, Ottiliavej 9, 2400 Valby, Denmark
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Frederix PLTM, Bosshart PD, Akiyama T, Chami M, Gullo MR, Blackstock JJ, Dooleweerdt K, de Rooij NF, Staufer U, Engel A. Conductive supports for combined AFM-SECM on biological membranes. Nanotechnology 2008; 19:384004. [PMID: 21832564 DOI: 10.1088/0957-4484/19/38/384004] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Four different conductive supports are analysed regarding their suitability for combined atomic force and scanning electrochemical microscopy (AFM-SECM) on biological membranes. Highly oriented pyrolytic graphite (HOPG), MoS(2), template stripped gold, and template stripped platinum are compared as supports for high resolution imaging of reconstituted membrane proteins or native membranes, and as electrodes for transferring electrons from or to a redox molecule. We demonstrate that high resolution topographs of the bacterial outer membrane protein F can be recorded by contact mode AFM on all four supports. Electrochemical feedback experiments with conductive cantilevers that feature nanometre-scale electrodes showed fast re-oxidation of the redox couple Ru(NH(3))(6)(3+/2+) with the two metal supports after prolonged immersion in electrolyte. In contrast, the re-oxidation rates decayed quickly to unpractical levels with HOPG or MoS(2) under physiological conditions. On HOPG we observed heterogeneity in the re-oxidation rate of the redox molecules with higher feedback currents at step edges. The latter results demonstrate the capability of conductive cantilevers with small electrodes to measure minor variations in an SECM signal and to relate them to nanometre-scale features in a simultaneously recorded AFM topography. Rapid decay of re-oxidation rate and surface heterogeneity make HOPG or MoS(2) less attractive for combined AFM-SECM experiments on biological membranes than template stripped gold or platinum supports.
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Affiliation(s)
- Patrick L T M Frederix
- M E Müller Institute for Structural Biology, Biozentrum of the University of Basel, CH-4056 Basel, Switzerland
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