A series of novel N-alkyl tetra- and perhydroquinoline derivatives and their hydrochlorides were prepared from tetrahydro- or trans-perhydroquinoline by direct alkylation with alkyl halides and subsequent precipitation with HCl gas. The antimicrobial activity of the resulting amines was evaluated in an agar diffusion assay. The minimal inhibitory concentrations (MIC) of the active compounds were determined by the microdilution method. In contrast to the tetrahydroquinolines, the perhydro analogues showed significant antifungal activity. In an assay for the detection of target enzymes in ergosterol biosynthesis, N-undecylperhydroquinoline was identified as an inhibitor of Δ8,7-isomerase.
Keywords: Antifungal activity; Enzyme inhibitor; Ergosterol biosynthesis; Quinoline; Δ8,7-Isomerase.