Synthesis and antimicrobial activity of some N-alkenyl-2-acylalkylidene-2,3-dihydro-1,3-benzothiazoles.

Several N-alkenyl-2-acylalkylidene-2,3-dihydro-1,3-benzothiazoles (4) were synthesized and tested for in vitro antibacterial activity against different Gram-positive and Gram-negative bacteria. Compounds 4 were also tested for antifungal activity against Saccharomyces cerevisiae. The findings clearly showed that all the compounds 4 were devoid of antifungal activity, whereas the compounds 4i-m,o-r were effective against the bacterial strains used. Compounds 4k,m,p,q proved to be the most active antibacterial agents showing in some cases minimum inhibitory concentrations (MIC) lower than chloramphenicol and gentamicin, used as reference compounds. In the case of two representative bacterial strains (Gram-positive and Gram-negative, respectively), a parabolic relationship was found between the antibacterial activity of compounds 4i-m,o-r expressed as log1/MIC and the molecular lipophilicity measured as RM values.