Synthesis of hybrid compounds of 24-nor-lupane triterpene and amino acids via C-28 amide linkage

Betulinic acid derivatives exhibit different biological activity against diversified targets, such as anticarcinogenic activity in experimental animals, anti-HIV, antihyperglycemia, and anti-inflammatory in humans. In this work, we investigated the synthetic procedure of 24-nor-3-oxo-20(29)-lupen-28-oic acid (1) derivatives. Starting from compound 1 and L-leucine methyl ester, we proceeded with amidification, reduction, and hydrolysis under basic conditions. Finally, three hybrid compounds were successfully synthesised and elucidated with spectral means.