New guaianolides from Artemisia selengensis.

A new guaianolide artselenin (1) and a new dimeric guaianolide artselenoid (2), along with 10 known compounds, were isolated from the aerial parts of Artemisia selengensis. Their structures were elucidated by spectroscopic methods. Two-dimensional NMR techniques were used to make complete assignments for the 1H- and 13C-NMR chemical shifts of the two new guaianolides.