- Total syntheses of the coumarin-containing natural products pimpinellin and fraxetin using Au(I)-catalyzed intramolecular hydroarylation (IMHA) chemistry
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The title natural products (1 and 2, respectively) have been synthesized by Au(I)-catalyzed intramolecular hydroarylation (IMHA) of the relevant aryl propiolate esters (e.g., 13), which were themselves formed by reaction of the corresponding phenols with either 3-(trimethylsilyl)propiolic acid or propiolic acid and N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride or dicyclohexylcarbodiimide. (±)-Purpurasol (3) was readily derived from fraxetin (2) by established procedures.
- Cervi, Aymeric,Aillard, Paul,Hazeri, Nourallah,Petit, Laurent,Chai, Christina L. L.,Willis, Anthony C.,Banwell, Martin G.
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p. 9876 - 9882
(2013/10/22)
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- Regio-and stereospecific synthesis of mono-β-d-glucuronic acid derivatives of combretastatin A-1
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Synthetic routes have been established for the preparation of regio-and stereoisomerically pure samples of the mono-β-d-glucuronic acid derivatives of combretastatin A-1, referred to as CA1G1 (5a) and CA1G2 (6a). Judicious choice of protecting groups for the catechol ring was required for the regiospecific introduction of the glucuronic acid moiety. The tosyl group proved advantageous in this regard. The two monoglucuronic acid analogues demonstrate low cytotoxicity (compared to CA1, 2) against selected human cancer cell lines, with CA1G1 being slightly more potent than CA1G2.
- Tanpure, Rajendra P.,Strecker, Tracy E.,Chaplin, David J.,Siim, Bronwyn G.,Trawick, Mary Lynn,Pinney, Kevin G.
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supporting information; experimental part
p. 1093 - 1101
(2010/09/09)
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- Development of synthetic methodology suitable for the radiosynthesis of combretastatin A-1 (CA1) and its corresponding prodrug CA1P
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Synthetic methodology has been established suitable for the preparation of combretastatin A-1 (CA1) and its corresponding phosphate prodrug salt (CA1P) in high specific activity radiolabeled form. Judicious selection of appropriate phenolic protecting groups to distinguish positions on the A-ring from the B-ring of the stilbenoid was paramount for the success of this project. Methylation of the C-4' phenolic moiety by removal of the tert- butyldimethylsilyl protecting group in the presence of methyl iodide was accomplished in excellent yield without significant Z to E isomerization. This step (carried out with 12C-methyl iodide as proof of concept in this study) represents the process in which a 14C radioisotope could be incorporated in an actual radiosynthesis. CA1 is a natural product isolated from the African bush willow tree (Combretum caffrum) that has important medicinal value due, in part, to its ability to inhibit tubulin assembly. As a prodrug, CA1P (OXi4503) is in human clinical trials as a vascular disrupting agent.
- Shirali, Anupama,Sriram, Madhavi,Hall, John J.,Nguyen, Benson L.,Guddneppanavar, Rajsekhar,Hadimani, Mallinath B.,Ackley, J. Freeland,Siles, Rogelio,Jelinek, Christopher J.,Arthasery, Phyllis,Brown, Rodney C.,Murrell, Victor Leon,McMordie, Austin,Sharma, Suman,Chaplin, David J.,Pinney, Kevin G.
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experimental part
p. 414 - 421
(2009/12/05)
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- Tubulin binding ligands and corresponding prodrug constructs
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A diverse set of tubulin binding agents have been discovered which are structurally characterized, in a general sense, by a semi-rigid molecular framework capable of maintaining aryl-aryl, pseudo pi stacking distances appropriate for molecular recognition of tubulin. In phenolic or amino form, these ligands may be further functionalized to prepare phosphate esters, phosphate salts, phosphoramidates, and other prodrugs capable of demonstrating selective targeting and destruction of tumor cell vasculature.
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