Synthesis and Purification of ۷-Prenyloxycoumarins and Herniarin as Bioactive Natural Coumarins

Objective(s) ۷-prenyloxycoumarins including ۷-isopentenyloxycoumarin, auraptene and umbelliprenin, and herniarin have been widely recognized as bioactive coumarins. This paper presents the ways to synthesis these compounds. Materials and Methods ۷-prenyloxycoumarins were synthesized by reaction between ۷-hydroxycoumarin (' M) and relevant prenyl bromides (۱.۵ M) in acetone at room temperature. The reaction was carried out in the presence of DBU (۱, ۸-diazabicyclo [۵.۴.۰] undec-۷-ene) (۲ M). After ۲۴ hr, the mixture was concentrated under reduced pressure. The compounds were purified by column chromatography. Results Three bioactive ۷-prenyloxycoumarins, namely, umbelliprenin, auraptene and ۷-isopentenyloxycoumarin, together with herniarin were synthesized from ۷-hydroxycoumarin under alkaline conditions (DBU) and then purified by column chromatography. The structures of the products were characterized by NMR spectroscopic method including ۱H- and ۱۳C-NMR experiments. Conclusion The method of synthesis for ۷-prenyloxycoumarins and herniarin which is presented here has not been reported yet. Moreover, for the first time, umbelliprenin was chemically prepared in this work.

Keywords:

Auraptene , Herniarin , ۷- Isopentenyloxycoumarin , ۷-Prenyloxycoumarins , Synthesis , Umbelliprenin