Chemical constituents from Ouratea floribunda: complete 1H and 13C NMR assignments of atranorin and its new acetyl derivative

Abstract

Chromatographic fractionation of the hexane extract from the wood of Ouratea floribunda (Ochnaceae) afforded friedelin (1), friedelanol (2), lupeol (3) and the depside atranorin (4). The structure elucidation of the isolated compounds was performed by spectrometric analysis involving comparison with literature data. The unambiguous assignments of ¹H and 13C NMR data of atranorin 4 and its acetyl derivative 4a are reported for the first time and involved ¹H-¹H homonuclear (COSY and NOESY) and ¹H-13C heteronuclear (HMQC and HMBC) NMR experiments.

Keywords

• Ouratea floribunda
• Ochnaceae
• atranorin
• monoacetylatranorin