The first study of the twigs of Pluchea indica L. in Vietnam isolated stigmasterol, 1-eicosanoyl glycerol, a long-chain saturated alcohol, 2-(prop-1-ynyl)-5-(5,6-dihydroxyhexa-1,3-diynyl)-thiophene, stigmasterol glucoside, and β-sitosterol glucoside. Their structures were determined on the basis of MS and NMR spectroscopic data.
The Ru(II)-N-heterocycle carbene complexes [RuCl2(η6-p-cymene)L] (L = 1-butyl-3-methylimid- azol-2-ylidene) and [RuCl(η6-p-cymene)L(pta)]Cl (pta = 1,3,5-triaza-7-phosphaadamantane) showed excellent catalytic activities (with turnover frequencies up to 1116 h-1) in the hydrogen transfer reduction of cinnamaldehyde and several ketones using propan-2-ol/KOH as a H-donor. Similar hydrogenations of trans-stilbene and cyclohexene were characterized by low conversions. The hydrogenation of 4-phenylbut-3-en-2-one and cinnamaldehyde proceeded with moderate selectivities of the formation of the saturated alcohol or of the of C=C hydrogenation (giving saturated ketone or saturated aldehyde). In the case of cinnamaldehyde, the unsaturated alcohol is initially formed; however, subsequent redox isomerization to the saturated aldehyde with the same catalyst diminishes its yield. The hydrogen transfer from formate to 4-phenylbut-3-en-2-one in an aqueous-organic two-phase mixture was also demonstrated.
Sterol, glycerol ester, and thiophene constituents from the twigs of Pluchea indica L. of Vietnam