Novel phenyl-1-benzoxepinols from butcher's broom (Rusci rhizoma)

Abstract

Two novel compounds, (3S)-2,3-dihydro-3-(4-hydroxyphenyl)-1-benzoxepin-8-ol (ruscozepine A) and (3S)-2,3-dihydro-3-(4-hydroxyphenyl)-8-methoxy-1-benzoxepin-7-ol (ruscozepine B) were isolated from butcher's broom (Rusci rhizoma) together with a biosynthetically possible phenylethanoid precursor, hydroxytyrosol. The structures were elucidated by spectroscopic methods such as 1D- and 2D-NMR (COSY, HSQC, HMBC, ROESY), and HR-EI-MS experiments. The absolute configuration of the ruscozepines was determined by electronic circular dichroism.