The synthesis and antimicrobial activities of some 1,4-naphthoquinones (II)

Abstract

In order to evaluate the antimicrobial effect of 2,3-disubstituted-1,4-naphthoquinone derivatives we newly synthesized several 2-chloro and 2-bromo-3-(substituted)-1,4-naphthoquninones. Amination reaction of 2,3-dihalo-1,4-naphthoquinones with aryl and aliphatic amines in ethanol gave 2-halo-3-(N-alkyl or N-aryl)-1,4-naphthoquinone derivatives (1a,b-10a,b) in 60%-90% yield. These derivatives subjected to antibacterial and antifungal activities, in vitro, against Bacillus subtilis ATCC 6633, Candida albicans 10231 and local, Pseudomonas aeruginosa NCTC10490, Staphylococcus aureus ATCC 6538p Escherichia coli NIHJ, Aspergillus niger KCTC 1231, Tricophyton mentagrophytes KCTC 6085. Among these derivatives, 1b, 6b and 7a showed the potent antibacterial activities, 1b, 8b and 9b have the antifungal activities. 1b is most effective in preventing the growth of Bacillus subtilis and Pseudomonas aeruginosa, Candida albicans, Aspergillus niger, Tricophyton mentagrophytes. Several of these compounds demonstrated a broad spectrum of activities in vitro.