Synthesis of methoxybenzoflavones and assignments of their NMR data


Yoongho Lim, Division of Bioscience and Biotechnology, Konkuk University, Hwayang-Dong 1, Kwangjin-Ku, Seoul, Korea 143–701. E-mail:

Dongsoo Koh, Department of Applied Chemistry, Dongduk Women's University, Hawolgok-Dong, Seongbuk-Ku, Seoul, Korea 136–714. E-mail:


A phytotoxic root exudate from Acroptilon repens was identified as 7,8-benzoflavone, an inhibitor of cytochrome P450 1A2 and activator of cytochrome P450 3A4. The synthetic 5,6-benzoflavone also is a potent phytotoxin. Six 7,8-benzoflavones and eight 5,6-benzoflavones were synthesized in this study. The NMR data for a few of these compounds have been previously reported; however, the NMR data for most of them have not been reported. For reference purposes, the complete NMR data for the 14 benzoflavones are described. Copyright © 2012 John Wiley & Sons, Ltd.