Synthesis and structure-activity relationships of novel amino/nitro substituted 3-arylcoumarins as antibacterial agents

A new series of amino/nitro-substituted 3-arylcoumarins were synthesized and their antibacterial activity against clinical isolates of Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) was evaluated. Some of these molecules exhibited antibacterial activity against S. aureus comparable to the standards used (oxolinic acid and ampicillin). The preliminary structure-activity relationship (SAR) study showed that the antibacterial activity against S. aureus depends on the position of the 3-arylcoumarin substitution pattern. With the aim of finding the structural features for the antibacterial activity and selectivity, in the present manuscript different positions of nitro, methyl, methoxy, amino and bromo substituents on the 3-arylcoumarin scaffold were reportedThanks are due to the Ministerio Español (PS09/00501), Xunta da Galicia (PGIDIT09CSA030203PR and PGIDT08MMA011200PR) and IN845B-2010/089 for the financial support. M.J.M. thanks to Fundação para a Ciência e Tecnologia for a PhD grant (SFRH/BD/61262/2009). S.V.R. thanks the Ministerio de Educación y Ciencia for a PhD grant (AP2008-04263)S