English: Example of oxidation of a secondary alcohol with pyridinium chlorochromate (PCC). The file was made with ChemBioDraw Ultra 14. The example is taken from the work of Yasuo Fujimoto et al. in 1984: https://dx.doi.org/10.1248/cpb.32.723 (open access). A more modern picture depicting the stereochemistry of lupeol and lupenone can be seen in the work of Chaturvedula Prakash and Indra Prakash in 2012: http://www.isca.in/IJPS/Archive/v1/i1/5.ISCA-RJPcS-2012-009.php (open access).