Oligo‐ and macrocyclic diterpenes in thymelaeaceae and euphorbiaceae occurring and utilized in yunnan (Southwest China) 3. Two new daphnane type 9,13,14‐orthoesters from Wikstroemia mekongenia

Abstract From the roots of Wikstroemia mekongenia W. W. Sm. two new isomeric diterpene esters, Wikstroemia factors M1 and M2, were isolated. They are polyfunctional 9,13,14‐orthobenzoates of the daphnane type 3‐deoxo‐1, 2α‐dihydro‐3β,5β‐dihydroxyresiniferonol‐6α,7α‐oxide carrying 3‐O‐(2,4‐decadienoyl) residues. The latter acyl groups are geometrically isomeric in M1 and M2. M1 and M2 are highly active as irritants on the mouse ear.