RESUMO
Seven new isomalabaricane derivatives, rhabdastins A-G (1-7), and a new monocyclic triterpene glycoside, rhabdastoside A (8), have been isolated from the methanol extract of the sponge Rhabdastrella globostellata, collected at Amami-oshima, Japan. Three of them were isolated as their corresponding methyl esters, rhabdastins A-D (1-3). Their structures were determined on the basis of spectroscopic and X-ray diffraction analyses. The isolated compounds were evaluated for their cytotoxicity against the proliferation of promyelocytic leukemia HL-60 cells. Compounds 4, 5, 7, and 11, possessing a cyclopentane side chain, exhibited weak activity, with IC(50) values of 21, 29, 44, and 11 µM, respectively, while compounds 1, 2, and 3, with a 2-substituted-propanoate side chain, were inactive at 100 µM. In addition, the mechanism of cytotoxicity of compounds 4 and 5 was investigated.
Assuntos
Antineoplásicos/isolamento & purificação , Antineoplásicos/farmacologia , Glicosídeos/isolamento & purificação , Glicosídeos/farmacologia , Poríferos/química , Triterpenos/isolamento & purificação , Triterpenos/farmacologia , Animais , Antineoplásicos/química , Cristalografia por Raios X , Ensaios de Seleção de Medicamentos Antitumorais , Glicosídeos/química , Células HL-60 , Humanos , Concentração Inibidora 50 , Estrutura Molecular , Triterpenos/químicaRESUMO
Goodwin-Lions-type sp2N/sp3N hybrid ligands R-BINAN-R'-Py possessing a C2 axis binaphthyl skeleton have been designed and synthesized. Combination of the new non-phosphine ligand with Ru(pi-CH2C(CH3)CH2)2(cod) has been revealed to catalyze the hydrogenation of aromatic ketones with high enantioselectivity of up to 99% ee. The reaction proceeds essentially without the need for any bases, but the reactivity is enhanced by the addition of KOt-C4H9 attaining an S/C ratio of up to 10 000. The success should expand the range of possibilities in designing catalysts not only for hydrogenation but also for many other reactions.
