New Water-Soluble Condensed Heterocyclic Compounds with Antimicrobial Activity Based on Annulation Reactions of 8-Quinolinesulfenyl Halides with Natural Products and Alkenes

Abstract

The annulation reactions of 8-quinolinesulfenyl halides with natural products and alkenes affording new water-soluble [1,4]thiazino[2,3,4-ij]quinolin-4-ium derivatives in high or quantitative yields are developed in this study. The reactions with styrene derivatives and terminal alkenes including allyl arenes proceed in a regioselective manner but with the opposite regiochemistry. The reactions with terminal alkenes including allyl arenes occur in an anti-Markovnikov fashion (regarding addition of the 8-quinolinesulfenyl electrophile to the double bond) to give 2-organyl-2H,3H-[1,4]thiazino[2,3,4-ij]quinolin-4-ium halides, while the reactions with styrene derivatives proceed in a Markovnikov fashion, leading to 3-substituted condensed heterocyclic compounds. In general, styrene derivatives demonstrate higher reactivity in the annulation reactions compared to the terminal alkenes. Antimicrobial activity of novel water-soluble compounds against Enterococcus durans, Bacillus subtilis and Escherichia coli are evaluated. The compounds with high antimicrobial activity are found. The annulation products of the reactions of 8-quinolinesulfenyl halides with 1H-indene, eugenol, methyl eugenol and 1-heptene, are superior in their activity compared to the antibiotic gentamicin.