Synthesis and biological evaluation of novel nitrogen- and sulfur-containing hetero-1,4-naphthoquinones as potent antifungal and antibacterial agents

1,4-Naphthoquinones are unique reagents in organic synthesis and have been employed in several well known and recently developed areas of application. Furthermore, these 1,4-naphthoquinones have demonstrated high reactivity in nucleophilic vinylic substitutions, in the preparation of sulfurated, (hetero)cyclic and several other transformations. This study describes the synthesis and biological evaluation of derivatives of monosulfurated naphthalene-1,4-dione (3), 3-chloro-2-ethoxy-naphthalene-1,4-dione (4), disulfurated naphthalene-1,4-dione (5), and symmetrical bis-1,4-naphthoquinones (7, 9) were obtained from the reaction of 2,3-dichloro-naphthaquinone (1) with S-, O-substituted mono-, di-, and tetrathiols, respectively. The structures of the novel products were characterized by spectroscopic methods.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► A convenient synthesis route of novel thio-substituted naphthalene-1,4-diones has been reported. ► Biological activities evaluated at low MIC against bacteria and fungi. ► (3a), (4c), (5d), and (5f) are promising as biologically active compounds.