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http://dx.doi.org/10.1002/anie.200500395 | DOI Listing |
Chem Pharm Bull (Tokyo)
January 2025
Department of Life Science and Biotechnology, Faculty of Chemistry, Materials and Bioengineering, Kansai University, 3-3-35 Yamate-cho, Suita, Osaka 564-8680, Japan.
Density functional theory calculations on the cyclization of di-t-butyl 2-(2-aminophenyl)-2-methyl malonate (1) to t-butyl 3-methyloxindole-3-carboxylate (2) reveal that acetic acid-assisted protonation of the carbonyl oxygen atom reduces the activation Gibbs free energy significantly lower than methanol-assisted pathways. Experimental data confirm that reaction concentration plays a pivotal role in oxindole formation. Experimental results also indicate distinct reaction mechanisms at low and high concentrations.
View Article and Find Full Text PDFFood Chem
January 2025
State Key Laboratory of Agricultural Products Safety/ Key Laboratory of Detection for Pesticide Residues and Control of Zhejiang, Institute of Agro-product Safety and Nutrition, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, PR China; Agricultural Ministry Key Laboratory for Pesticide Residue Detection, Hangzhou 310021, PR China. Electronic address:
Ethiprole is a second-generation phenylpyrazole insecticide used in agricultural production as an alternative to fipronil due to its lower toxicity to bees. Ethiprole amide is chiral metabolite of ethiprole, but information regarding its formation and degradation in vegetables is limited. Here, the absolute configuration of ethiprole amide enantiomer was determined through circular dichroism, and the behaviors of chiral ethiprole and its metabolites in five kinds of vegetables were studied through field experiments.
View Article and Find Full Text PDFOrg Lett
January 2025
State Key Laboratory of Antiviral Drugs, Pingyuan Laboratory, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China.
Highly asymmetric (3+3) annulation of diaziridines with oxiranes via C-N bond cleavage in diaziridine was achieved under 10 mol % of chiral copper(II) complex as the catalyst under mild reaction conditions. With Cu(OTf) as the Lewis acid and C-symmetric imidazolidine-pyrroloimidazolone pyridine as the ligand, diverse tetrahydro-[1,3,4]-oxadiazines were obtained by stereospecific C-N/C-O bond formation in moderate to good yields (up to 93% yield) and high diastereo- (>20:1 dr) and enantioselectivities (up to 92% ee). The catalytic cycle and stereochemical model were proposed by DFT calculation.
View Article and Find Full Text PDFChemistry
January 2025
Karlsruhe Institute of Technology, Institute for biological interfaces 1 (IBG-1), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, GERMANY.
Enantioselectivity is a key advantage of enzymatic catalysis. Understanding the most important factors influencing enantioselectivity necessitates thorough investigation for each specific enzyme. In this study, we explore various approaches to optimize reaction conditions for organosilicon production using an immobilized Cytochrome C recently tailored via directed evolution.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
University of Toronto, Dept. of Chemistry, 80 St. George Street, M5S 3H6, Toronto, CANADA.
A copper-catalyzed enantioselective synthesis of borylated 1-pyrrolines from γ,δ-unsaturated oxime esters is reported. Twenty-four novel 1-pyrroline derivatives are reported in yields ranging from 26% to 96% and enantioselectivities from 74.5:25.
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