RESUMEN
Three new pimarane diterpenes, eutypellenoids Aâ»C (1â»3), together with a known compound, eutypenoid C (4), were isolated from the culture extract of Eutypella sp. D-1 derived from the Arctic region. Compounds 1â»3 possessed an uncommon tetrahydrofuran-fused pimarane diterpene skeleton. The structures of all compounds were determined by detailed spectroscopic analysis, electronic circular dichroism (ECD) analysis, as well as a comparison with the literature data. Antibacterial, antifungal, and cytotoxic activities of these compounds were evaluated. Compound 2 displayed antibacterial activity against Staphylococcus aureus and Escherichia coli with MIC values of 8 and 8 µg/mL, respectively. Additionally, compound 2 showed antifungal activity against Candidaparapsilosis, Candida albicans, Candida glabrata, and Candida tropicalis with MIC values of 8, 8, 16, and 32 µg/mL, respectively. Furthermore, compound 2 exhibited moderate cytotoxic activity against HCT-116 cell line with IC50 value of 3.7 µM.
Asunto(s)
Abietanos/química , Diterpenos/química , Xylariales/química , Antibacterianos/química , Antibacterianos/farmacología , Antifúngicos/química , Antifúngicos/farmacología , Regiones Árticas , Línea Celular Tumoral , Escherichia coli/efectos de los fármacos , Hongos/efectos de los fármacos , Furanos/química , Células HCT116 , Humanos , Pruebas de Sensibilidad Microbiana/métodos , Staphylococcus aureus/efectos de los fármacosRESUMEN
We develop a copper-catalyzed disilylation of polysubstituted pent-1-en-4-yn-3-yl acetate derivatives, which in one pot furnishes the bis(silyl)-substituted vinylallenes in moderate yields under mild reaction conditions. The reaction shows broad substrate scope and single stereoselectivity. Besides, we develop a method to decrease the electrocyclization temperature of vinylallenes for the synthesis of methylenecyclobutenes by installing bis(silyl) substituents. And the effect of a silyl substituent on electrocyclization of vinylallenes was studied via DFT computation. The synthetic method features broad substrate scope and excellent stereoselectivity.
RESUMEN
The three-component coupling method for regio- and stereoselective difunctionalization of allenes with allenyl ethers, bis(pinacolato)diboron, and gem-dichlorocyclobutenones as electrophiles was reported, yielding a variety of highly functionalized cyclobutenone products tethering with an alkenylborate fragment. The polysubstituted cyclobutenone products also underwent diverse transformations.
Asunto(s)
Cobre , Éteres , Catálisis , EstereoisomerismoRESUMEN
We report copper-catalyzed borylation and silylation of dichlorocyclobutenones, which furnish the boron-substituted and silicon-substituted polyfunctionalized cyclobutenones in high yields. The reactions proceed under mild reaction conditions, show broad substrate scope, and display high chemoselectivity. In addition, a series of transformations of the corresponding products has been realized.