Synthesis of 2,3-Seco-Derivatives of Dihydrobetulonic Acid and its Methyl Ester

摘要

2,3-Secolupane aldehydonitriles with an isopropyl fragment were synthesized via Beckman fragmentation of ring A of triterpene α-hydroxyoximes obtained from dihydrobetulonic acid and its methyl ester. Redox transformation of the aldehydonitriles at C-3 led to the formation of the corresponding 3-hydroxy- and 3-carboxy-derivatives. The MTT assay found that only the triterpene oximes possessed moderate cytotoxic activity against HCT 116, RD TE32, MS, and PC-3 tumor cells (IC50 27.8–61.7 μM) among the synthetic products.