Synthesis and the biological evaluation of the structural units of drummondin C.

Drummondin C (1) is an antibiotic isolated from a bioassay-directed fractionation of Hypericum drummondii (Grev. & Hook.)T.&G. It showed significant activity against the Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis and the acid-fast bacterium Mycobacterium smegmatis. Two structural units of drummondin C, the 8-acetyl-5,7-dihydroxy-2,2-dimethylchromene (6) and 5-acetyl-3-methyl-filicinic acid (9), were synthesized to determine the relative importance of the two substructure portions to the antibiotic activity of the compound. The low antimicrobial activity of 6 and 9 demonstrates the necessity of both units for the antibiotic activity of drummondin C.