Thujaplicinol is either of two isomeric tropolone-related natural products. They are found in tree species primarily in bark, needles, xylem, of the family of Cupressaceae like the Cupressus, Thuja, Juniperus and Thujopsis. The thujaplicinols are structurally equivalent to the thujaplicins with an additional hydroxyl group. They belong to the class of natural terpenoids having two free hydroxyl groups at C3 and C5 position.
The thujaplicinols are highly volatile compounds. It is known that the presence of such tropolones, including alpha-tropolone and its isopropyl derivatives, result in the high natural durability of wood species, such as western red cedar, juniper and cypress.