Abstract The xanthones 1-hydroxy-3, 6-dimethoxy-(2), 2, 4-dichloro-1, 3-dihydroxy-6- methoxy-(6), 2-chloro-1, 3-dihydroxy-6-methoxy-(7), 4-chloro-1, 3-dihydroxy-6-methoxy-(8) and 2-chloro-1-hydroxy-3, 6-dimethoxy-8-methyl-9H-xanthen-9-one (11) were isolated from the lichen Pertusaria sulphurata Mull. Arg. The unambiguous synthesis of compounds (6),(7),(8),(11) and some other chloroxanthones, and the chlorination of 1, 3-dihydroxy-6- ...
