Effective Three‐Step Construction of Betulonic Acid Hybrids with Heterocycle‐Containing Peptidomimetic Fragments

Synthesis of hybrid molecules containing a natural betulonic acid core and a peptidomimetic moiety was carried out by a three‐step transformation: e. g. (i) Ugi four‐component reaction involving heterocyclic amines to obtain some new azido‐substituted peptidomimetics; (ii) isolation of the compounds from the natural raw materials and obtaining betulonic acid propargyl esters; (iii) Cu‐catalyzed cycloaddition of peptide‐structured azides to betulonic acid propargyl esters, resulting in the construction of target molecules. The microbiological properties of the hybrid compounds and their precursors were tested against two Gram‐positive and two Gram‐negative bacterial strains.