Acid Rearrangement of Secoiridoids Related to Oleuropein and Secologanin

Acid treatment of an iridoid glycoside results in the cleavage of the acetal bond between the sugar unit and the monoterpenoid aglycon. We examined the acid rearrangement of secoiridoids such as oleuropein and secologanin and their reduction products oleuropeinol and secologaninol, to examine whether similar behaviour also occurs in this case.