By reacting 4-hydroxycoumarin with long-chain acyl chlorides, a number of new 3-acyl derivatives were prepared and the relationship was studied between their structures and activities against Staphylococcus aureus ATCC 6538, Staphylococcus epidermidis ATCC 12228, and Propionibacterium acnes ATCC 11827. Antibacterial activity was associated with enolic tautomers of a tricarbonylmethane group bearing a lipophilic side chain (undec-10-enoyl, undec-10-ynoyl, palmitoyl or octadec-9-enoyl). A newly synthesized 2-acyl derivative of 2H-indene-1,3-dione containing the same tricarbonylmethane motif showed a comparable activity.

A number of new 3-acyl-4-hydroxycoumarins endowed with marked antibacterial activity is synthesized (yields not given) and structure-activity relationships are discussed. -(CRAVOTTO*, G.; TAGLIAPIETRA, S.; CAPPELLO, R.; PALMISANO, G.; CURINI, M.; BOCCALINI, M.; Arch.