RESUMO
Bioassay-guided fractionation of an 80% MeOH extract of Juglan sinensis leaves and twigs has resulted in the isolation of three new triterpenes (1-3) and two new sesquiterpenes (4-5) along with two known sesquiterpenes (6-7). The new compounds were determined to be 3ß, 11α, 19α, 24, 30-pentahydroxy-20ß, 28-epoxy-28ß-methoxy-ursane (1), 1α, 3ß-dihydroxy-olean-18-ene (2), 2α, 3α, 23-trihydroxy-urs-12-en-28-oic acid 28-O-ß-d-glucopyranoside (3), (4S, 5S, 7R, 8R, 14R)-8, 11-dihydroxy-2, 4-cyclo-eudesmane (4), 15-hydroxy-α-eudesmol-11-O-ß-d-glucopyranoside (5), by spectroscopic analysis. The cytotoxicity of compounds (1-7) against four cancer cell lines such as B16F10, Hep-2, MCF-7 and U87-MG was evaluated. Compounds 1, 2, 6 and 7 showed potent cytotoxicity against all of four cancer cell lines, respectively.
Assuntos
Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/farmacologia , Juglans/química , Sesquiterpenos/química , Sesquiterpenos/farmacologia , Triterpenos/química , Triterpenos/farmacologia , Antineoplásicos Fitogênicos/isolamento & purificação , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Humanos , Neoplasias/tratamento farmacológico , Folhas de Planta/química , Sesquiterpenos/isolamento & purificação , Triterpenos/isolamento & purificaçãoRESUMO
The Pd(PPh3)4-catalyzed decarboxylation of buta-2,3-dienyl 2'-alkynoates allows the rapid construction of 2-alkynyl buta-1,3-dienes. The carbon-carbon bond-forming reaction occurs at the central position of an allene moiety.
Assuntos
Alcadienos/síntese química , Alcinos/química , Alcinos/síntese química , Paládio/química , Polienos/química , Polienos/síntese química , Alcadienos/química , Catálise , Descarboxilação , Estrutura MolecularRESUMO
Cycloisomerizations of allenynes to allenenes have been studied in the presence of catalytic amounts of [Hg(OTf)2] in acetonitrile. The catalytic system is quite effective for terminal 1,6-allenynes: allenenes were obtained in reasonable to high yields. However, treatment of allenynes with disubstituents at the allenic terminal carbon yielded a triene and/or allenene as a major product(s) depending upon the substituents.
Assuntos
Alcadienos/síntese química , Alcinos/química , Compostos de Mercúrio/química , Mesilatos/química , Alcadienos/química , Catálise , Cristalografia por Raios X , Ciclização , Modelos Moleculares , Estrutura Molecular , EstereoisomerismoRESUMO
Cycloisomerizations of allenynes to allenenes have been studied in the presence of catalytic amounts of [Au(PPh3)]SbF6 in dichloromethane or GaCl3 in toluene. Both catalytic systems are quite effective for terminal 1,6-allenynes. However, they showed different reactivities toward allenynes with di-substituents at the allenic terminal carbon. For the GaCl3-catalyzed reactions, allenenes were obtained in reasonable to high yields. However, for a Au(I)-catalyzed reaction, a triene was obtained in a poor yield. Thus, GaCl3 serves as an effective catalyst for the cycloisomerization of allenynes bearing a terminal alkyne to give cyclic allenenes in reasonable to high yields.