Isolation and synthesis of two hydroxychavicol heterodimers from Piper nudibaccatum

Two hydroxychavicol heterodimers comprising phenylpropanoid and monoterpene constituent units, named nudibaccatumins A (1) and B (2), were isolated as an inseparable mixture from the aerial parts of Piper nudibaccatum. Their absolute configurations were confirmed by total synthesis using ortho-alkylation of hydroxychavicol with myrtenyl bromide as the key reaction. The two new compounds (1 and 2) and their synthetic analogues (3-8) were evaluated for XO inhibitory activity.