New neolignans from krameria tomentosa A. St.-Hil

Abstract

A phytochemical investigation of the roots of Krameria tomentosa A. St.-Hil. led to the isolation of five neolignans, two of them with novel structures [1,1'-(E)-propenyl-4-methoxy-3,4'-oxyneolignan (ottomentosa) and 2-(2'-hydroxy-4',6'-dimethoxyphenyl)benzofuran-5-carboxylic acid (sobraline)] and three known compounds [eupomatenoid 6, dihydrocarinatidin and 2-(2',4'-dihydroxyphenyl)-5-(E)-propenylbenzofuran]. The structural characterization of the compounds isolated was established based on infrared spectroscopy, mass spectrometry, one- and two-dimensional nuclear magnetic resonance, along with comparison with spectral data described in the literature. © 2012 Sociedade Brasileira de Química.