THE FIRST 13-VINYL DERIVATIVES OF BERBERINE: SYNTHESIS AND ANTIMICROBIAL ACTIVITY

Abstract

A method for the synthesis of berberine 13-vinyl derivatives has been developed consisting of an initial reaction of triethyl orthoformate with CH acids in the presence of catalytic amounts of p-toluenesulfonic acid followed by the reaction of electrophilic ethoxyethylenes with dihydroberberine. 13-Vinyldihydroberberines are resistant to spontaneous oxidation or disproportionation and can be oxidized to the corresponding 13-substituted ionic forms with silver chloride. The synthesized vinyl berberines were demonstrated to inhibit the development of a number of especially dangerous microorganisms.