An efficient and highly atom-economical tandem Pd/Au-catalyzed route to α-sulfenylated carbonyl compounds from terminal propargylic alcohols and thiols has been developed. This one-step procedure has a wide substrate scope with respect to substituents at the α-position of the alcohol. Both aromatic and aliphatic thiols generated the α-sulfenylated carbonyl products in good to excellent yields. A mechanism is proposed in which the reaction proceeds through a Pd-catalyzed regioselective hydrothiolation at the terminal triple bond of the propargyl alcohol followed by an Au-catalyzed 1,2-hydride migration.
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http://dx.doi.org/10.1002/chem.201304111 | DOI Listing |
An Acad Bras Cienc
January 2025
Universidade Federal do Pará, Instituto de Ciências Exatas e Naturais, Laboratório de Investigação Sistemática em Biotecnologia e Biodiversidade Molecular, Rua Augusto Corrêa, 01, 66075-110 Belém, PA, Brazil.
In the present study, 5-Hydroxy-2-(Oleoyloxymethyl) -4H-pyran-4-one (KMO 3), and their chelated with Cu(II) and Fe(III) ions were synthesized to explore their inhibitory activity against tyrosinase and cytotoxicity. To this end, the structures of the obtained compounds were confirmed by ATR/FT-IR, 13C and 1H-NMR, and UV-vis techniques. The results show that chelating fatty ester presents the bands at 1567m, 1511w cm-1 attributed to the coordinated carbonyl (Cu(II)←[O=C]2), and the bands at 1540m, 1519m cm-1 which were attributed to the coordinated carbonyl (Fe(III)←[O=C]3).
View Article and Find Full Text PDFOrg Biomol Chem
January 2025
Department of Chemistry, Faculty of Arts and Sciences, Amasya University, Amasya, Turkey.
Herein, a new metal-free, molecular chlorine-free, environmentally friendly, atom-economical, short time, inexpensive and simple operation method with mild reaction conditions for chlorination of alkenes, cyclic alkenes, ,-unsaturated carbonyl compounds, heteroaromatics, and natural products was reported with up to 96% yields using trichloroisocyanuric acid (TCCA) as the electrophilic chlorine source and TBACl as the nucleophilic chlorine source. It was demonstrated with bicyclic alkene benzonorbornadiene that regioselective chlorobromination and dibromination reactions can be carried out through TCCA/TBABr redox reactions, where TCCA acts as an oxidant in the presence of TBABr. The structures of the redox products were confirmed as a result of control experiments conducted with the newly presented DBI/TBACl and DBI/TBABr halogenation pairs.
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
January 2025
CERENA - Civil Engineering Research and Innovation for Sustainability, IST-ID, Av. António José de Almeida 12, 1049-001, Lisbon, Portugal.
Polypropylene (PP) disposable face masks (DFMs) are essential for limiting airborne infectious diseases. This study examines the behavior of DFMs under three scenarios: (i) exposure to the natural environment, (ii) simulated high-energy aquatic environments through an abrasion test, and (iii) incorporation into cement-based mortars. In the natural weathering experiment, after 117 days, the DFMs exhibited photodegradation, resulting in chemical alterations in carbonyl and hydroxyl groups.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Institute of Organic Chemistry, University of Leipzig, 04103 Leipzig, Germany.
The enantioselective synthesis of 1,4-dicarbonyl compounds continues to pose a significant challenge in organic synthesis, and a catalytic process which generates two adjacent stereogenic centers with full stereochemical control is lacking until now. The 1,4-relationship of the functional groups requires an Umpolung strategy as one of the α-carbonyl positions has to be inverted into an electrophilic center to react with a normal enolate. We report herein the highly enantio- and diastereoselective addition of silyl ketene acetals toward electrophilic 1-azaallyl cations to furnish chiral 4-hydrazonoesters, which are masked 1,4-dicarbonyl compounds.
View Article and Find Full Text PDFJ Agric Food Chem
January 2025
State Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensor Technology and Health, Central China Normal University, Wuhan 430079, PR China.
4-Hydroxyphenylpyruvate dioxygenase (HPPD) is a crucial herbicide target in current research, playing an important role in the comprehensive management of resistant weeds. However, the limited crop selectivity and less effectiveness against grass weeds of many existing HPPD inhibitors, limit their further application. To address these issues, a series of novel HPPD inhibitors with fused ring structures were designed and synthesized by introducing an electron-rich indazolone ring and combining it with the classical triketone pharmacophore structure.
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