Complete assignment of the ¹H and ¹³C NMR spectra of garciniaphenone and keto‐enol equilibrium statements for prenylated benzophenones

Abstract

This article reports the structural elucidation by IR, UV and MS spectroscopic data along with 1H and 13C NMR chemical shift assignments of two benzophenones isolated from the fruit pericarp of Garcinia brasiliensis Mart. (Clusiaceae): garciniaphenone, (1R,5S,7S)-3-benzoyl-4-hydroxy-6,6-dimethyl-5,7-di(3-methyl-2-butenyl)bicyclo[3.3.1]non-3-ene-2,9-dione, a novel triprenylated benzophenone; and 7-epi-clusianone, a tetraprenylated benzophenone that has already been extracted from another species of the same family. Furthermore, the keto-enol tautomeric equilibrium at solution-state was described for these compounds by 1D and 2D NMR spectral methods and one attempt to rationalize the different ratios between the noted tautomers was based on stereochemical features.

Antioxidant, cytotoxic and antimutagenic activities of 7-epi-clusianone obtained from pericarp of Garcinia brasiliensis

“…The bioactive compound was identified as the prenylated benzophenone, 7-epiclusianone, using spectrometric techniques (IR, UV, MS and 1 H and 13 C NMR). The data were compared with those verified in a previous study that investigated the chemical structure of this compound with an authentic sample analyzed by chromatography (Derogis et al, 2008;Yen, Chang, & Duh, 2005).…”

A new type of Brazilian propolis: Prenylated benzophenones in propolis from Amazon and effects against cariogenic bacteria

“…These benzophenones are typical metabolites of Clusiaceae (Guttiferae) (Derogis et al, 2008;Masullo, Bassarello, Suzuki, Pizza, & Piacente, 2008), a family with over 1000 species, many widespread throughout Brazil. Phytochemical investigations of Clusia grandiflora, C. nemorosa and Clusia rosea have detected polyisoprenylated benzophenones in fruits, roots and leaves (Oliveira et al, 1999).…”

Inhibition of cysteine proteases by a natural biflavone: behavioral evaluation of fukugetin as papain and cruzain inhibitor

“…These fractions were then pooled in 10 groups according to their similarities in thin layer chromatography (TLC). The group was rechromatographed with mixtures of n-hexane/ethylacetate and ethyl-acetate/ethanol, and the main fraction was recrystallized several times using methanol solutions, yielding 1.05 g of fukugetin, as described by Derogis 17 . The structure elucidation was obtained by NMR, MS, UV, and IR techniques of this isolated compound which were appraised by comparison with literature values [18][19][20] .…”