The X-Ray Crystal Structure and Photochemistry of 22-α-Hydroxystictan-3-One; a Triterpenoid Keto Alcohol From Pseudocyphellaria Species

Abstract

The crystal structure of 22α-hydroxystictan-3-one has been determined by X-ray diffraction. Rings A and B of this keto alcohol have been shown to adopt twist boat conformations. Despite the presence of the twist boat ring A system photochemical rearrangement of the keto alcohol proceeds to give 3,4-secostictane derivatives analogous to those afforded by other 3-oxo-4,4-dimethyl steroids and triterpenoids in which ring A adopts a flattened chair conformation.