RESUMO
Four meroterpenoids (3a, 3b, 4 and 5), a prenylated pyran-2-one (2) along with the known compounds 7-O-geranylscopoletin (1), and thapsitranstagin (6) have been isolated from the roots of Thapsia transtagana. The presence of 1 and 2 supports the biogenetic hypothesis that transtaganolides, a group of bioactive metabolites, are meroterpenoids which come from an O-prenylated coumarin via successive pericyclic reactions.
Assuntos
Produtos Biológicos/biossíntese , Piranos/isolamento & purificação , Terpenos/isolamento & purificação , Thapsia/química , Espectroscopia de Ressonância Magnética , Piranos/metabolismo , Espectrometria de Massas por Ionização por Electrospray , Terpenos/metabolismoRESUMO
The sigma-enynyl complex [TpRu(C(Ph)=C(Ph)C identical to CPh)(P-MeiPr2)] efficiently catalyses the regioselective cyclization of alpha,omega-alkynoic acids to yield endocyclic enol lactones having ring size up to 12 atoms.
Assuntos
Lactonas/síntese química , Alcinos , Ácidos Carboxílicos/química , Catálise , Ciclização , Lactonas/química , Compostos Organometálicos/química , Rutênio/químicaRESUMO
The synthesis of (+/-)-11alpha-hydroxy-3-oxo-6alphaH,7alphaH, 10betaMe-eudesman-1,2-4,5-dien-6,12-olide (1), previously isolated from Melanoselinum decipiens, is described, and its structure has been corrected.