Heterodimers of Aromadendrane Sesquiterpenoid with Benzoquinone from the Chinese Liverwort Mylia nuda .

Mylnudones A-G ( 1 - 7 ), unprecedented 1,10- seco -aromadendrane-benzoquinone-type heterodimers, and a highly rearranged aromadendrane-type sesquiterpenoid ( 8 ), along with four known analogs ( 9 - 12 ), were isolated from the liverwort Mylia nuda . Compounds 1 - 6 and 7 , bearing tricyclo[6.2.1.0 2,7 ] undecane and tricyclo[5.3.1.0 2,6 ] undecane backbones, likely formed via a Diels-Alder reaction and radical cyclization, respectively. Their structures were determined by spectroscopic analysis, computational calculation, and single-crystal X-ray diffraction analysis. Dimeric compounds displayed cytoprotective effects against glutamic acid-induced neurological deficits.