A new general methodology for the synthesis of various functionalized privileged oxygen heterocyclic scaffolds, viz. pyrones, coumarins, and benzannulated coumarins, is developed. The synthesis proceeds through carbanion-induced ring transformation of lactones with various methylene carbonyl compounds followed by DDQ-mediated unprecedented oxidative cleavage of oxaylidenes intermediates. Studies of the mechanism of the conversions of oxaylidene intermediates into corresponding carbonyl compounds in the presence of DDQ revealed that the reactions took place via the formation of a Michael adduct instead of an intermolecular charge transfer complex. The methodology offers the fabrication of diverse privileged scaffolds with tolerance for many functional groups onto the oxygen heterocyclic molecular framework.
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http://dx.doi.org/10.1039/c3ob40859k | DOI Listing |
Background: Alopecia areata (AA) is a T-cell-mediated autoimmune disease that significantly impacts patient quality of life. The breakdown of hair follicle immune privilege underlies AA pathogenesis. However, the precise mechanism of this breakdown remains unclear.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
Department of Chemistry, New York University, New York, New York 10003, United States.
Complexity-generating reactions that access three-dimensional products from simple starting materials offer substantial value for drug discovery. While oxygen-containing heterocycles frequently feature unique, nonaromatic architectures such as spirocyclic rings, exploration of these chemical spaces is limited by conventional synthetic approaches. Herein, we report a copper-catalyzed annulation and alkene transposition cascade reaction that enables a modular preparation of complex, spirocyclic ethers from readily available alkenol substrates via a copper-catalyzed annulation and transannular 1,5-hydrogen atom transfer-mediated C-H functionalization.
View Article and Find Full Text PDFArch Pharm (Weinheim)
November 2024
Department of Medicinal Chemistry and Pharmaceutical Sciences Research Center, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran.
Radioprotectors are synthetic compounds, natural products, or biological agents that are administered before irradiation to protect normal cells against ionizing radiation (IR)-induced injuries. We have designed novel hybrid (E)-kojyl-styryl-sulfones 10a-n by applying the pharmacophore hybridization strategy to combine key structural motifs of the natural antioxidant kojic acid and the emerging radioprotector Ex-RAD (recilisib sodium). These hybrids were successfully synthesized and characterized with (E)-geometry.
View Article and Find Full Text PDFInfect Immun
December 2024
Zoology Department, Faculty of Science, Cairo University, Giza, Egypt.
To control schistosomiasis mansoni, it is important to attempt preventing the worms' egg-induced pathology in the liver and limiting pathogen transmission following egg exit from the intestines to the exterior. Therefore, the present study aimed to clarify the reasons behind the decades-long riddle of periovular granulomas downmodulation in the liver, but not the small intestine, with the progression of murine schistosomiasis mansoni. Outbred female CD-1 mice were percutaneously exposed to 15 cercariae.
View Article and Find Full Text PDFChem Biol Interact
December 2024
Department of Experimental Oncology, Institute for Oncology and Radiology of Serbia, Pasterova 14, 11000, Belgrade, Serbia. Electronic address:
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