We describe here the highly stereoselective total synthesis of the C acetogenins (3)- and (3)-elatenynes having a 7,12-dibromo-6,9--10,13- adjacent bis-tetrahydrofuran (THF) core. The present synthesis features a highly stereoselective, protecting group-dependent, chelate-controlled intramolecular amide enolate alkylation (IAEA) for the synthesis of key intermediate 7-hydroxy-6,7--6,9--THF intermediate 10, deployment of the sequential ate complex (-BuLi/DIBAL-H) reduction/Keck allylation/cross metathesis (CM) protocol for the stereoselective introduction of the C(10)-C(15) unit, a sequential Sharpless asymmetric dihydroxylation (SAD)/intramolecular Williamson etherification for the construction of the 10,13--THF ring, and a modified Nakata chloromethanesulfonate-mediated S2 displacement for the 7,12-dibromo functionality. Furthermore, our strategy based on chelate-controlled IAEA methodology would provide access to any member of the C adjacent bis-THF acetogenin class.
View Article and Find Full Text PDFColorectal cancer (CRC) is the third most prevalent form of cancer in the United States and results in over 50,000 deaths per year. Treatments for metastatic CRC are limited, and therefore there is an unmet clinical need for more effective therapies. In our prior work, we coupled high-throughput chemical screens with patient-derived models of cancer to identify new potential therapeutic targets for CRC.
View Article and Find Full Text PDFThe highly stereoselective construction of C-symmetric ,- and ,-2,6-dioxabicyclo[3.3.0]octane (fused -tetrahydrofuran) skeletons and has been accomplished via a novel stereodivergent double intramolecular amide enolate alkylation of common cyclization substrate through the judicious choice of "chelate" versus crown ether-promoted "nonchelate" control.
View Article and Find Full Text PDFThe skin is an important physiological barrier against external stimuli, such as ultraviolet radiation (UV), xenobiotics, and bacteria. Dermal inflammatory reactions are associated with various skin disorders, including chemical-induced irritation and atopic dermatitis. Modulation of skin inflammatory response is a therapeutic strategy for skin diseases.
View Article and Find Full Text PDFAdiponectin is an adipocytokine with insulin-sensitizing, anti-atherogenic, and anti-inflammatory properties. Adiponectin secretion-inducing compounds have therapeutic potential in a variety of metabolic diseases. Phenotypic screening led to the discovery that 5,7-dihydroxy-8-(1-(4-hydroxy-3-methoxyphenyl)allyl)-2-phenyl-4H-chromen-4-one (compound 1) had adiponectin secretion-inducing activity during adipogenesis in human bone marrow mesenchymal stem cells (hBM-MSCs).
View Article and Find Full Text PDFThe first asymmetric total synthesis and subsequent structure revision of (-)-bisezakyne A, a Laurencia C15 acetogenin from Alpysia oculifera, has been accomplished. Our substrate-controlled synthesis of this oxolane natural product features a highly stereoselective "protecting-group-dependent" intramolecular amide enolate alkylation strategy for the synthesis of the key 9,10-trans-9,12-cis-10-hydroxytetrahydrofuran intermediate through "nonchelate" control. In addition, our synthesis determined the absolute configuration of the halogenated marine natural product.
View Article and Find Full Text PDFImpaired immune responses in skin play a pivotal role in the development and progression of chemical-associated inflammatory skin disorders. In this study, we synthesized new flavonoid derivatives from macakurzin C, and identified in vitro and in vivo efficacy of a potent anti-inflammatory flavonoid, Compound 14 (CPD 14), with its underlying mechanisms. In lipopolysaccharide (LPS)-stimulated murine macrophages and IFN-γ/TNF-α-stimulated human keratinocytes, CPD 14 significantly inhibited the release of inflammatory mediators including nitric oxide (NO), prostaglandins, and cytokines (IC50 for NO inhibition in macrophages: 4.
View Article and Find Full Text PDFThe concise, highly stereoselective, substrate-controlled asymmetric total syntheses of both 2,5-cis- and 2,5-trans-tetrahydrofuranoid nematocidal oxylipids from the Australian brown algae Notheia anomala have been accomplished in a stereodivergent fashion. The highly stereoselective intramolecular amide enolate alkylation strategy provides access to both stereoisomers of the 3-hydroxy-2,5-disubstituted tetrahydrofuran core of these marine natural products through chelate and nonchelate control, which is driven by the C3-hydroxy protecting group. This approach offers an optional and highly stereoelective access to any of the eight possible stereoisomers of the 2,5-disubstituted-3-oxygenated tetrahydrofuran skeleton, an important structural feature which is present in many biologically active natural products.
View Article and Find Full Text PDFHeme oxygenase-1 (HO-1) and ATPase inhibitory factor (ATPIF) 1 is often overexpressed in different types of cancer cells. Chrysin is a naturally-occurring flavonoid with antioxidant potentials, but also known to promote apoptosis. We have synthesized four chrysin derivatives and found compounds 1 and 4 remarkably upregulated the expression of HO-1, a cytoprotective enzyme.
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