Synthetic transformations of higher terpenoids. XXI.* preparation of phlomisoic acid and its N-containing derivatives
A method for preparing 15,16-epoxylabda-8(9),13(16),14-trien-18-oic (phlomisoic) acid was proposed. Its structure was confirmed by an XSA. N-containing derivatives of phlomisoic acid that contained amines, hydrazides, and methyl esters of amino acids on the C-18 atom in addition to (2-oxo-2-aminoacetyl)-substituted derivatives of the C-16 methyl ester of phlomisoic acid were prepared.