Estudo químico de Aniba gardneri (Meissn.) Mez

Abstract

The leaves of the Aniba gardneri tree (Meissn.) Mez contain n-dotriacontanol, n-dotriacontyl acetate, n-dotriacontanoic acid, he benzyl benzoate, benzyl salicylate, 4-methoxyparacotoin, trans-5,6-dehydrocavaine, plus three new substances. Of these, one was identified as cis-5,6-dehydrocavaine by spectral measurements and by conversion to a dihydroderivative which was identical to the analogous derivative of trans-5,6-dehydrocavaine. The two remaining substances are addition products of two units of 5,6-dehydrocavaine (aniba-dimer A) and of 4-methoxyphenylcoumaline and 5,6-dehydrocavaine (aniba-dimer B). Nuclear magnetic resonance and mass spectrometry revealed that these dimers belong to a structural type proposed by Edwards et al., J. Chem. Soc., (C), 413 (1967), for photodimers of hispidine analogs. Photosynthesis of cis-5,6-dehydrocavaine and aniba-dimers A and B was performed by exposing the appropriate monomers to light. A mechanism for the reaction is proposed, which contributes to the elucidation of the stereochemistry of the dimers. By thin-layer chromatography of crude extracts obtained in the dark, it was found that dimers and isomers occur in the leaves, but not in the branches of Aniba gardneri.