A facile route for the synthesis of limonidilactone analogues from andrographolide

Labdane diterpenes are an important class of natural products with a wide variety of biological properties. (−)-Limonidilactone is a labdane diterpene with a novel skeleton isolated from Vitex limonifolia. A new semi-synthetic route from andrographolide, the major constituent of Andrographis paniculata, has been described towards the synthesis of novel labdanes having a limonidilactone type skeleton.