4,5-Di-O-methylhiascic acid, a new tridepside from the lichens Parmelia pseudofatiscens and Parmelia horrescens

Abstract

The tridepside 4,5-di-O-methylhiascic acid (8) has been isolated from the lichen Parmelia pseudofatiscens. The structure of this compound followed from the spectroscopic data and has been confirmed by total synthesis. This new tridepside was also shown to occur in the lichen Parmelia horrescens.