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Transformation of D-glucitol into its 1,6-diazido deriva- tive allowed its conversion into the polyhydroxylated amino- azepane ring in a one-pot reaction using Ph3P and H2O.

Zusammenfassung Les desaminogirollines syn 2′S,3′S et 2′R,3′R ont ete preparees par dedoublement de leurs derives diastereoisomeres. La synthese stereoselective de l'enantiomere naturel de la girolline a ete realisee a partir du D(-)arabinose : la condensation de cet ose avec l'acetate de formamidine fournit le 4(5)-[1′,2′,3′-trihydroxypropyl]-imidazole ; la chaine laterale est chloree puis aminee via l'azide terminal ; le noyau imidazole est amine ensuite en 2 par diazotation suivie de reduction en presence de rhodium.

Phytochemical investigation of a methanolic extract of the stem of Guatteriopsis friesiana afforded two new 7,7-dimethylaporphine alkaloids, 6,6a-dihydrodemethoxyguadiscine (1) and guatteriopsiscine (3), together with demethoxyguadiscine (2), liriodenine (4), corypalmine (5), and coreximine (6). Their structures were elucidated on the basis of spectroscopic methods (UV, IR, EIMS, HRESIMS, 1D/2D NMR). The absolute configurations of 1 and 3 were determined from the circular dichroism curves. The presence of 7,7-dimethylaporphine alkaloids in this species is important for the chemotaxonomy of Guatteriopsis. Antimicrobial activity of compounds 1-5 was investigated, and 4 showed activity against Rhodococcus equi, with a MIC value of 10 microg x mL(-1).

From an ethanolic extract of Peschiera fuchsiaefolia three quaternary alkaloids have been isolated and their structures determined from their spectral data as 12-methoxy-4-methylvoachalotine, 12-methoxy-4-methylvoachalotine ethyl ester and fuchsiaefoline. Analyses of the 13 C NMR spectra of some sarpagine alkaloids were carried out to confirm the structures of these compounds.

Fractionation of an ethereal extract of Peschiera fuchsiaefolia resulted in the isolation of decarbomethoxyvoacamine, demethylvoacamine, voacamidine, perivine, 16-epiaffinine and voacanginehydroxyindolenine, together with the previously reported alkaloids voacamine, voacangine, voachalotine and affinisine. Analysis of the 13 C NMR spectra of the bisindole alkaloids and of 16-epiaffinine is reported.