Naturally occurring dibenzofurans. Part 6. Synthesis of didymic acid
Abstract
The synthesis of the lichen dibenzofuran didymic acid (1)(3-hydroxy-7-methoxy-1-pentyl-9-propyldibenzofuran-2-carboxylic acid) by intramolecular Ullmann coupling of methyl 5-bromo-4-(2-bromo-5-methoxy-3-propylphenoxy)-2-methoxy-6-pentylbenzoate (34) and methyl 5-iodo-4-(2-iodo-5-methoxy-4-nitro-3-propylphenoxy)-2-methoxy-6-pentylbenzoate (32) and appropriate further transformations, is described.