Antibacterial and Herbicidal Activity of Ring-Substituted 2-Hydroxynaphthalene-1-carboxanilides

In this study, a series of twenty-two ring-substituted 2-hydroxynaphthalene-1？carboxanilides were prepared and characterized. Primary in vitro screening of the synthesized compounds was performed against Staphylococcus aureus, three methicillin-resistant S. aureus strains, Mycobacterium marinum, M. kasasii, M. smegmatis. and M. avium paratuberculosis. The compounds were also tested for their activity related to inhibition of photosynthetic electron transport (PET) in spinach ( Spinacia oleracea L.) chloroplasts. 2-Hydroxy- N-phenylnaphthalene-1-carboxanilide and 2-hydroxy- N-(3-trifluoromethylphenyl)naphthalene-1-carboxamide (IC 50 = 29 μmol/L) were the most active PET inhibitors. Some of tested compounds showed the antibacterial and antimycobacterial activity against the tested strains comparable or higher than the standards ampicillin or isoniazid. Thus, for example, 2-hydroxy- N-(3-nitrophenyl)naphthalene-1-carboxamide showed MIC = 26.0 μmol/L against methicillin-resistant S. aureus and MIC = 51.9 μmol/L against M. marinum, or 2-hydroxy- N-phenylnaphthalene-1-carboxamide demonstrated MIC = 15.2 μmol/L against M. kansasii. The structure-activity relationships for all compounds are discussed.