Neolignanas da Licaria aritu

Abstract

"Louro aritú", Licaria aritu Ducke, is an arboreous Lauraceae species of the Amazon reglon which occurs in regular abundance in the vicinity of Manaus. The specimen examined in the present thesis was collected at Reserva Florestal Adolfo Ducke of Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus-Itacoatiara highway. The chemical investigation of benzene and ethanol extracts of trunk wood of the species led to the isolation of three compounds: isoeugenol (XXIV), a propenylphenol which is not very widely distributed in plants, licarin A and licarin B, two novel neolighans. The structures of (2S,3S)-2,3-dihydro-2-(4'-hydroxy-3'-methoxyphenyl)-7-methoxy-3-methyl-5-trans-propenylbenzofuran (XXIII) and of (2S,3S)-2,3-dihydro-7-methoxy-3-methyl-2-(3',4'-methylenedioxyphenyl)-5-trans-propenylbenzofuran (IV) were assigned respectively to licarin A and licarin B, through the analysis of infrared, ultraviolet, mass and proton magnetic resonance spectra. The determination of the absolute configurations relied on the comparison of optical rotatory dispersion curves of the licarins and known 2,3-trans-2-aril-3-methyl-dihydrobenzofurans.