Eupulcherol A (1), a novel triterpenoid with an unprecedented carbon skeleton, was isolated from Euphorbia pulcherrima. Its structure was determined by comprehensive analysis of spectroscopic data, including HRESIMS and 1D and 2D NMR, and the absolute configuration was defined by single crystal X-ray diffraction analysis. Biological studies showed that compound 1 possessed anti-Alzheimer's disease (AD) bioactivity, which could delay paralysis of transgenic AD Caenorhabditis elegans. A plausible biogenetic pathway for eupulcherol A (1) was also proposed.
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http://dx.doi.org/10.1039/c9ob02334h | DOI Listing |
J Org Chem
December 2024
Department of Pharmacy, The First Affiliated Hospital, Jinan University, Guangzhou 510630, China.
Nine new structurally diverse filicinic acid-based meroterpenoids (-) with four kinds of carbon skeletons were isolated from the rhizomes of . Their structures, including the absolute configurations, were elucidated by comprehensive analysis of spectroscopic data, quantum chemical calculations, and single-crystal X-ray diffraction. Structurally, compounds - feature an unprecedented 6/6/5/6/6/6 hexacyclic system with a rare oxaspiro[4.
View Article and Find Full Text PDFJ Agric Food Chem
December 2024
State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193, People's Republic of China.
Sativene-related sesquiterpenoids including -sativene analogs are a large member of fungal secondary metabolites with phytotoxic and growth-promoting effects on different plants. In this report, a series of sativene-related sesquiterpenoids with diverse carbon skeletons (-, sativene/isosativene/-sativene/cyclosativene/-isosativene ring systems) were isolated from the plant pathogenic fungus based on a molecular networking strategy. The undescribed structures were elucidated based on NMR spectra, X-ray diffraction analysis, chemical derivation, and calculated electronic circular dichroism calculations.
View Article and Find Full Text PDFACS Appl Mater Interfaces
December 2024
Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China.
Artificial photosynthesis of hydrogen peroxide (HO) from ambient air, water, and sunlight has attracted considerable attention recently. Despite being extremely challenging to synthesis, sp carbon-conjugated covalent organic frameworks (COFs) can be powerful and efficient materials for the photosynthesis of HO due to desirable properties. Herein, we report the designed synthesis of an sp carbon-conjugated COF, BTD-spc-COF, from benzothiadiazole and triazine units with high crystallinity and ultralarge mesopores (∼4 nm).
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
TU Dresden: Technische Universitat Dresden, Faculty of Chemistry and Food Chemistry, Bergstraße 66, 01069, Dresden, GERMANY.
Polycyclic tetramate macrolactams (PoTeMs) represent a growing class of bioactive natural products that are derived from a common tetramate polyene precursor, lysobacterene A, produced by an unusual bacterial iterative polyketide synthase (PKS) / non-ribosomal peptide synthetase (NRPS). The structural and functional diversity of PoTeMs is biosynthetically elaborated from lysobacterene A by pathway-specific cyclizing and modifying enzymes. This results in diverse core structure decoration and cyclization patterns.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
South China University of Technology, School of Chemistry and Chemical Engineering, Wushan St., 510640, Guangzhou, CHINA.
Electroreduction of CO2 to CO represents a highly promising way for artificial carbon cycling, but obtaining high selectivity over a wide potential window remains a challenge due to the sluggish CO generation and diffusion kinetics. Here we report an integration of long-range P modified asymmetrical bismuth atomic site on an ordered macroporous carbon skeleton with mesoporous "wall" (MW-BiN3-POMC) for efficient electroreduction of CO2. In-depth in-situ investigations with theoretical computations reveal that the incorporation of long-range P atom is able to strengthen the orbital interaction between the C 2p of CO2 and Bi 6p, thereby establishing an electronic transport bridge for the activation of CO2 molecule.
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