Structure elucidation and complete NMR spectral assignments of four new diterpenoids from Smallantus sonchifolius

摘要

Four new diterpenoids, named smaditerpenic acid A-D, together with five known compounds, were isolated from the H2O extract of the leaves of Smallantus sonchifolius (yacon) cultivated in Liaoning, China and their structures were elucidated on the basis of one- and two-dimensional NMR (including H-1, C-13-NMR, H-1-H-1 COSY, HSOC, TOCSY, HMBC, and ROESY), electrospray ionization mass spectrometry (ESI-MS), and chemical methods. Copyright (C) 2008 John Wiley & Sons, Ltd.