Synthesis and biological evaluation of novel amide derivatives of pentacyclic triterterpenes as inhibitors of glycogen phosphorylase

Eight novel amide derivatives of corosolic acid were synthesized by acylation, amidation and hydrolysis reactions, etc. Six novel amide derivatives of oleanolic acid were synthesized by acylation, alkylation and reduction reactions, etc. Biological evaluation of the target compounds as inhibitors of glycogen phosphorylase(GP)has been described. Results indicated that eleven derivatives exhibited moderate-to-good inhibitory activities against glycogen phosphorylase. Among them, four target compounds possess better inhibition effects than lead compounds and compound 6 show the best inhibition effect with the IC₅₀ of 11. 2 μmol/L.