A new, straightforward and high yielding procedure to convert oleanolic acid derivatives into the corresponding δ-hydroxy-γ-lactones, by using the convenient oxidizing agent magnesium bis(monoperoxyphthalate) hexahydrate (MMPP) in refluxing acetonitrile, is reported. In addition, a two-step procedure for the preparation of oleanolic 12-oxo-28-carboxylic acid derivatives directly from Δ12-oleananes, without the need for an intermediary work-up, and keeping the same reaction solvent in both steps, is described as applied to the synthesis of 3,12-dioxoolean-28-oic acid.
- oleanolic acid
- bismuth(III) triflate
Salvador, J. A. R., Moreira, V. M., Pinto, R. M. A., Leal, A. S., & Paixão, J. A. (2012). Efficient oxidation of oleanolic acid derivatives using magnesium bis(monoperoxyphthalate) hexahydrate (MMPP). Beilstein Journal of Organic Chemistry, 8, 164-169. https://doi.org/10.3762/bjoc.8.17