Keywords: 18-norabietane.svg Skeletal formula of 18-norabietane 7-isopropyl-1 4a-dimethyl-dodecahydro-1H-phenanthrene the main constituent of fichtelite Created using http //www acdlabs com/download/chemsk html ACD/ChemSketch 12 0 and Inkscape Optimized with vim Own 2011-07-13 Fvasconcellos Diterpenes |