Synthesis and antituberculosis activity of conjugates of the diterpenoid isosteviol and the drug dimephosphon

Conjugates of the diterpenoid isosteviol (16-oxo-ent-beyeran-19-oic acid) and the drug dimephosphon (1,1dimethyl-3-oxobutylphosphonic acid dimethyl ester) were synthesized. They inhibited completely growth of M. tuberculosis (H37Rv, in vitro) with MIC values of 5–10 μg/mL (MIC value of the antituberculosis drug isoniazid in a control was 0.5 μg/mL).