Neoclerodane Diterpenes from <i>Baccharis crispa</i>

Abstract

In order to confirm the previously proposed stereochemistry for bacrispine ( 1 ), several high-field 2D NMR (500 MHz) experiments were carried out. Complete NMR assignments, as well as the validation of the relative stereochemistry of 1-deoxybacrispine ( 2 ), were established. In an investigation of the aerial parts of Baccharis crispa, a medicinal plant from Argentina, two new neoclerodanes ( 4, and 5 ) have been isolated and their structures determined by spectroscopic means.