New labdane-type diterpenoids from Leonurus heterophyllus

Abstract

Chemical investigation of the aerial part of Leonurus heterophyllus led to the isolation and characterization of the seven labdane-type diterpenoids 1-7, including six new ones, 1-6. Compounds 4 and 5 were isolated as a C(15) epimer pair. The determination of the structures and relative configurations of the new compounds were mainly based on 1D- and 2D-NMR spectroscopic methods, and comparison of their NMR data with related compounds. The structure of compound 7 was confirmed by X-ray crystallographic analysis. © 2012 Verlag Helvetica Chimica Acta AG.