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[reaction: see text] Condensation of a benzopyranonphthalide with Michael acceptors provides an efficient, general method for regiospecific preparation of xanthones as well as linear and angular polycyclic aromatic systems containing a xanthone fragment.
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http://dx.doi.org/10.1021/ol0354876 | DOI Listing |
J Org Chem
March 2025
Pingyuan Laboratory, State Key Laboratory of Antiviral Drugs, Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education, School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, Henan 450001, P. R. China.
An effective strategy to synthesize 2,4-diaminoquinoline compounds has been efficaciously developed via a TMSOTf/TfOH-promoted [4 + 2] annulation of ynamides with 2-aminoarylnitriles. Compared with the reported transition-metal catalysts, this metal-free promotion system presented a remarkable advancement, enabling the facile and regiospecific assembly of 2,4-diaminoquinoline frameworks with wide functional group compatibility and moderate to excellent yields.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Key Laboratory of Applied Chemistry of Chongqing Municipality and Chongqing Key Laboratory of Soft-Matter Material Chemistry and Function Manufacturing, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China.
Achieving catalytic asymmetric functionalization of methylenecyclopropanes (MCPs) by selective C-C bond cleavage is a notable challenge due to the intricate reaction partners involved. In this work, we report that chiral aldehyde/palladium combined catalysis enables the asymmetric functionalization of MCPs with NH-unprotected amino acid esters. This reaction proceeds through a regiospecific branched ring-opening mechanism, resulting in optically active α,α-disubstituted α-amino acid esters bearing nonconjugated terminal alkene units.
View Article and Find Full Text PDFBeilstein J Org Chem
November 2024
Department of Chemistry and Chemical Engineering, Florida Institute of Technology, 150 West University Boulevard, Melbourne, Florida 32901-6975, USA.
J Am Chem Soc
October 2024
Carbohydrate-Based Drug Research Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.
Widely distributed in nature, sulfated glycan epitopes play important roles in diverse pathophysiological processes. However, due to their structural complexity, the preparation of glycan epitopes with structurally defined sulfation patterns is challenging, which significantly hampers the detailed elucidation of their biological functions at the molecular level. Here, we introduce a strategy for site-specific chemical sulfation of glycan epitopes, leveraging enzymatic sialylation and desialylation processes to precisely control the regio-specificity of sulfation of disaccharide or trisaccharide glycan backbones.
View Article and Find Full Text PDFFoods
August 2024
Department of Chemistry, Institute of Food Sciences, Warsaw University of Life Sciences, Nowoursynowska st. 159c, 02-787 Warsaw, Poland.
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