Chlorinated Coumarins from the Polypore Mushroom <i>Fomitopsis officinalis</i> and Their Activity against <i>Mycobacterium tuberculosis</i>

An EtOH extract of the polypore mushroom <i>Fomitopsis officinalis</i> afforded two new naturally occurring chlorinated coumarins, which were identified as the previously synthesized compounds 6-chloro-4-phenyl-2<i>H</i>-chromen-2-one (<b>1</b>) and ethyl 6-chloro-2-oxo-4-phenyl-2<i>H</i>-chromen-3-carboxylate (<b>2</b>). The structures of the two isolates were deduced by <i>ab initio</i> spectroscopic methods and confirmed by chemical synthesis. In addition, an analogue of each was synthesized as 7-chloro-4-phenyl-2<i>H</i>-chromen-2-one (<b>3</b>) and ethyl 7-chloro-2-oxo-4-phenyl-2<i>H</i>-chromen-3-carboxylate (<b>4</b>). All four compounds were characterized physicochemically, and their antimicrobial activity profiles revealed a narrow spectrum of activity with lowest MICs against the <i>Mycobacterium tuberculosis</i> complex