- Synthesis of amide isosteres of schweinfurthin-based stilbenes
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The schweinfurthins are plant-derived stilbenes with an intriguing profile of anti-cancer activity. To obtain analogues of the schweinfurthins that might preserve the biological activity but have greater water solubility, a formal replacement of the central olefin with an amide has been explored. Two pairs of amides have been prepared, each containing the same hexahydroxanthene “left half” joined through an amide linkage to two different “right halves.” In each series, the amide has been inserted in both possible orientations, placing the carbonyl group on the tricyclic ABC ring system and the amine on the D-ring, or placing the amine on the hexahydroxanthene and the carbonyl group on the D-ring. The four new schweinfurthin analogues have been tested in the NCI 60 cell line screen, and in both cases the more active isomer carried the carbonyl group on the C-ring.
- Stockdale, David P.,Beutler, John A.,Wiemer, David F.
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- Synthesis of a Coumarin-Based Analogue of Schweinfurthin F
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The natural schweinfurthins are stilbenes with significant antiproliferative activity and an uncertain mechanism of action. To obtain a fluorescent analogue with minimal deviation from the natural structure, a coumarin ring system was annulated to the D-ring, creating a new analogue of schweinfurthin F. This stilbene was prepared through a convergent synthesis, with a Horner-Wadsworth-Emmons condensation employed to form the central stilbene olefin. After preparation of a tricyclic phosphonate via a recent and more efficient modification of the classic Arbuzov reaction, condensation was attempted with an appropriately substituted bicyclic aldehyde but the coumarin system did not survive the reaction conditions. When olefin formation preceded generation of the coumarin, the stilbene formation proceeded smoothly and ultimately allowed access to the targeted coumarin-based schweinfurthin analogue. This analogue displayed the desired fluorescence properties along with significant biological activity in the National Cancer Institute’s 60-cell line bioassay, and the pattern of this biological activity mirrored that of the natural product schweinfurthin F. This approach gives facile access to new fluorescent analogues of the natural schweinfurthins and should be applicable to other natural stilbenes as well.
- Beutler, John A.,Dey, Patrick N.,Schroeder, Chloe M.,Wiemer, David F.
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p. 16824 - 16833
(2021/11/16)
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- Xylochemical synthesis and biological evaluation of shancigusin c and bletistrin g
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The biological activities of shancigusin C (1) and bletistrin G (2), natural products isolated from orchids, are reported along with their first total syntheses. The total synthesis of shancigusin C (1) was conducted by employing the Perkin reaction to forge the central stilbene core, whereas the synthesis of bletistrin G (2) was achieved by the Wittig olefination followed by several regiose-lective aromatic substitution reactions. Both syntheses were completed by applying only renewable starting materials according to the principles of xylochemistry. The cytotoxic properties of shancigusin C (1) and bletistrin G (2) against tumor cells suggest suitability as a starting point for further structural variation.
- Efferth, Thomas,Geske, Leander,Kauhl, Ulrich,Opatz, Till,Saeed, Mohamed E. M.,Schüffler, Anja,Thines, Eckhard
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supporting information
(2021/06/16)
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- Synthesis and biological evaluation of a ring analogs of the selective CB2 inverse agonist SMM-189
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Microglia are the principle cell type driving sustained neuroinflammation in neurodegenerative diseases such as Alzheimer's, Parkinson's, and Multiple Sclerosis. Interestingly, microglia locked into a chronic M1 pro-inflammatory phenotype significantly up-regulate the cannabinoid receptor 2 (CB2) expression. Our approach to exploiting CB2 as a therapeutic target in neuroinflammatory diseases focuses on the development of selective CB2 inverse agonists to shift microglia bias to a M2 pro-wound healing phenotype. Herein we report work designed to refine the structure activity relationship of the 2,6-dihydroxy-biphenyl-aryl-methanone CB2 inverse agonist scaffold. A series of analogs of our lead compound SMM-189 were synthesized and measured for affinity/selectivity, potency, and efficacy in regulating cAMP production and β-arrestin recruitment. In this series compound 40 demonstrated a significant increase in potency and efficacy for cAMP stimulation compared to SMM-189. Akin to our lead SMM-189, this compound was highly efficacious in biasing microglia to an M2 pro-wound healing phenotype in LPS stimulated cell lines. These results advance our understanding of the structure–activity relationship of the 2,6-dihydroxy-biphenyl-aryl-methanone scaffold and provide further support for regulating microglia activation using CB2 inverse agonists.
- Alghamdi, Sahar S.,Mustafa, Suni M.,Moore II, Bob M.
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- Total synthesis of virgatolide b via exploitation of intramolecular hydrogen bonding
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A full account of the enantioselective total synthesis of virgatolide B is reported. Key features of the synthesis include an sp3-sp2 Suzuki-Miyaura cross-coupling of a β-trifluoroboratoamide with an aryl bromide, regioselective intramolecular carboalkoxylation, and a 1,3-anti-selective Mukaiyama aldol reaction. Intramolecular hydrogen bonding governed the regioselectivity of the key spiroketalization step, affording the natural product as a single regioisomer.
- Hume, Paul A.,Furkert, Daniel. P.,Brimble, Margaret A.
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p. 5269 - 5281
(2014/06/23)
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- Total synthesis of virgatolide B
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The first total synthesis of the benzannulated spiroketal virgatolide A is presented. Key features include sp3-sp2 Suzuki coupling of an enantiomerically enriched β-trifluoroboratoamide and an aryl bromide, regioselective intramolecular carboalkoxylation, and a 1,3-anti-selective Mukaiyama aldol reaction followed by global deprotection/cyclization with regioselectivity governed by internal hydrogen bonding.
- Hume, Paul A.,Furkert, Daniel P.,Brimble, Margaret A.
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supporting information
p. 4588 - 4591
(2013/09/24)
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- A xerogel-sequestered selenoxide catalyst for brominations with hydrogen peroxide and sodium bromide in an aqueous environment
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(Chemical Equation Presented) 4-(Hydroxymethyl)phenyl benzyl selenoxide (4) sequestered in a halide-permeable, Class II xerogel formed from 10/90 (mol/mol) 3-aminopropyltriethoxysilane/tetraethoxysilane catalyzes the bromination of organic substrates (4-pentenoic acid, 3,5-dihydroxybenzoic acid, 1,3,5-trimethoxybenzene, N-phenylmorpholine, and N,N-dimethylaniline) with NaBr and H2O2. Catalyst performance (reaction rate) when sequestered within the halide-permeable xerogel is 23-fold greater in comparison to xerogel-free catalyst in solution. The catalyst is easily separated from the reaction mixture via filtration and the recovered catalyst can be reused without loss of activity through formation of the first 80 mol of product per mole of catalyst.
- Bennett, Stephanie M.,Tang, Ying,McMaster, Danielle,Bright, Frank V.,Detty, Michael R.
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p. 6849 - 6852
(2008/12/22)
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- A new family of biisoquinoline chelates
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Four 8,8′-diaryl-substituted 3,3′-biisoquinoline ligands have been synthesized and characterized. The key feature of this new family of chelates is their endotopic but sterically non-hindering nature. All four ligands were made from a common 8-bromoisoquinolin-3-ol precursor; between three and twelve synthetic steps were necessary to obtain the products. The reported synthetic procedures allow for gram-scale production of these biisoquinolines. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Durola, Fabien,Hanss, David,Roesel, Pirmin,Sauvage, Jean-Pierre,Wenger, Oliver S.
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p. 125 - 135
(2007/10/03)
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- Total synthesis of (±)-Taiwaniaquinol B via a domino intramolecular Friedel-Crafts acylation/carbonyl α-tert-alkylation reaction
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The first synthesis of taiwaniaquinol B, a 6-nor-5(6→7)abeoabietane-type diterpenoid exhibiting the uncommon fused 6-5-6 tricyclic carbon skeleton, was accomplished in 15 steps. A Lewis acid-promoted tandem intramolecular Friedel-Crafts/carbonyl α-tert-alkylation reaction was exploited as the core strategy for the synthesis of the sterically congested 1-indanone-containing tricyclic structure. This multiple carbon-carbon bond forming reaction exploits the unique reactivity of Meldrum's acid. The facile precursor synthesis makes this a useful methodology for the expedient modification and assembly of sterically congested 1-indanone-containing ring systems. Copyright
- Fillion, Eric,Fishlock, Dan
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p. 13144 - 13145
(2007/10/03)
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- Synthesis of the racemate of the stereoisomer at C-6a of BE-40644, a bioactive metabolite of Actinoplanes sp. with a sesquiterpene-substituted p-benzoquinone structure.
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BE-40644 is a tetracyclic metabolite of Actinoplanes sp. A 40644 possessing a sesquiterpene-substituted p-benzoquinone structure with cis-fused B/C ring stereochemistry that inhibits the human thioredoxin system as the well as the growth of several cancer cell lines. Its B/C trans-fused stereoisomer at C-6a was synthesized as a racemate starting from geranylacetone and 3,5-dihydroxybenzoic acid.
- Tsujimori,Mori
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p. 167 - 171
(2007/10/03)
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- Process for preparing pyrogallol
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Pyrogallol is prepared by (A) reacting a halo compound of formula STR1 where X represents Br or I, R1 represents hydrogen, secondary or tertiary alkyl of up to 10 carbon atoms, carboxy or alkoxycarbonyl of 2-5 carbon atoms and R2 represents hydrogen or alkyl of 1-4 carbon atoms, with an alkali metal alkoxide of formula ROM where M represents an alkali metal and R represents alkyl of 1-4 carbon atoms, to replace each X by OR, and then (B) dealkylating each OR and each OR2 where R2 represents alkyl of 1-4 carbon atoms and removing the R1 group where this is not hydrogen.
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