Antonio A.L. Mesquita

Xanthonolignoids from Kielmeyera and Caraipa species—13C NMR spectroscopy of xanthones

Abstract Kielcorin and the cadensins A and B , isolated respectively from Kielmeyera coriacea and Caraipa densiflora (Guttiferae), were shown to be xanthonolignoids. The structure of (5S,6S)-6(or 5)-hydroxymethyl-5(or 6)-(4″-hydroxy-3″-methoxyphenyl)-2,3:3′,4′-(2′-methoxyxanthono)-1,4-dioxane was proposed for kielcorin by analysis of high resolution MS and PMR spectra. The carbon shifts of xanthone were assigned and used in the 13 C NMR spectral confirmation of the proposed structure.

Flavonoids from four compositae species

Abstract The isolation of umbelliferone from Eupatorium angustifolium , of alnustin, 5,7,8-trimethoxyflavone, 7-hydroxy-3,5,8-trimethoxyflavone and 3,5,7,8-tetramethoxyflavone from Achyrocline satureoides var. albicans ; of cirsimaritin from Baccharis eleagnoides ; and of genkwanin from Symphyopappus polystachyus is reported.

Xanthones from Tovomita pyrifolium

Abstract The wood of Tovomita pyrifolium (Guttiferae) contains the novel tovopyrifolins A [1,6-dihydroxy-7-methoxy-5-prenyl-6′,6′-dimethylpyrano (2′,3′:3,2)xanthone], B (1,5-dihydroxy-3,4-dimethoxyxanthone) and C (1,3,5-trihydroxy-2-methoxyxanthone) and also the known tovophyllins A and B [structure revised to 1,6-dihydroxy-5-prenyl-6′, 6′-dimethylpyrano(2′,3′:3,2)-6″,6″-dimethylpyrano(2″,3″:7,8)xanthone].

Anthraquinones from Vismia species

Abstract 1,8-Dihydroxy-3-methyl-6-methoxyanthraquinone (physcion) and two derivatives, 7-( trans -3-methyl-1-butenyl)-physcion (vismiaquinone) and 7-(3-methyl-2-oxobutyl)-physcion (vismiaquinone B), were isolated respectively from Vismia cayennensis and V. japurensis .

Xanthonolignoids from Kielmeyera coriacea

Abstract The synthesis of kielcorin and the tentative identification of kielcorin B (5-hydroxymcthyl-6-guaiacyl-2,3:3′,2′,4′-methoxyxanthone-1,4-dioxane), isomeric xanthonolignoids of Kielmeyera coriacea are reported.

Chemosystematic implications of Xanthones in Bonnetia and Archytaea

On morphological grounds, the systematic position of the genera Bonnetia and Archytaea is controversial. On chemical grounds, the presence of 1,7,– 1,7,8- and 1,6,7,8- oxygenated xanthones in Bonnetia stricta and Archytaea multiflora suggests their affinity with the Kielmeyeroideae of the Guttiferae and thus the homogeneity of the Bonnetiaceae in their modern circumscription.

Marupone, a benzophenone from Moronobea pulchra

Abstract The trunk wood of Moronobea pulchra Ducke (Guttiferae) contains a yellow pigment designated marupone for which the structure of 2-geranyl-1,3-dihydroxy-6-methoxybenzophenone is proposed.

Xanthones from Tovomita Excelsa

Abstract The trunk wood of Tovomita excelsa (Guttiferae) from north-eastern Brazil contains, besides betulinic acid, 1,5-dihydroxy-6-methoxyxanthone, 1,6-dihydroxy-5-methoxyxanthone, 5,6-dihydroxy-1-methoxyxanthone and 1,7- dihydroxy-6-methoxyxanthone.

Xanthones from Bonnetia dinizii

Abstract The wood of Bonnetia dinizii (Guttiferae) was found to contain besides sitosterol, stigmasterol, betulinic acid and sakuranetin, 1,7-, 1,7,8-, 1,6,7,8- and 1,2,3,5-oxygenated xanthones, including the novel 1,3-dihydroxy-2,5-dimethoxyxanthone.

γ-Lactones from Mezilaurus synandra☆

Abstract The trunk wood of Mezilaurus synandra contains the known alkaloids coclaurine, corytuberine and norcinnamolaurine, besides the novel (2 R ,3 R ,4 S )-2-dodec-ω-enyl-3-hydroxy-4-methylbutanolide.