Straightforward partial synthesis of four diastereomeric 2,3-dihydroxy-olean-12-en-28-oic acids from oleanolic acid

The four diastereomeric 2,3-dihydroxy-olean-12-en-28-oic acids (maslinic, augustic, bredemolic and 3-epi-maslinic acid) were easily accessed from one single starting material, oleanolic acid. The procedures allow the medium-to-large scale preparation of these valuable starting materials. Except for maslinic acid, the triterpenoic acids showed only a low cytotoxicity towards several human tumor cell lines. (C) 2015 Elsevier Ltd. All rights reserved.