Kirenol is one of the biologically active diterpenoids from Siegesbeckia pubescens. In terms of the high content and typical structure, many ent-diterpenoids separated from S. pubescens were presumed to be biologically related to kirenol. Among them, epoxy-pimarane diterpenoids are belonging to a special family of naturally occurring compounds that attracted our attentions on their putative biosynthesis pathway and biological activities. Here, we designed and synthesized two known 14,16-epoxy-pimarane diterpenoids (2 and 3) and five 8,15-epoxy-pimarane diterpenoids (4-8) from kirenol. Their absolute structures were determined by 1D and 2D NMR data and the absolute configurations of 4 were confirmed by X-ray crystallographic data. Their inhibition effects on factor Xa (FXa) were evaluated to assess the potentiality of epoxy-pimarane diterpenoids as FXa inhibitor agents.
Keywords: Epoxy-pimarane diterpenoids; Factor Xa; Kirenol; Siegesbeckia; Siegesbeckia pubescens; X-ray crystallographic data.
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