The first total synthesis of carminic acid

Abstract

The first synthesis of carminic acid (7β-D-glucopyranosyl-1-methyl-3,5,6,8-tetrahydroxy-9,10-anthraquinone-2-carboxylic acid), was accomplished by direct C-glucosylation of ethyl 3,5,8,9,10-pentamethoxy-1-methylanthracene-2-carboxylate, here synthesized, which affords ethyl 7-(2,3,4,6-tetra-O-benzyl-β-D-glucopyranosyl)-3,5,8,9,10-pentamethoxy-1-methylanthracene-2-carboxylate and carminic acid by regeneration of the masked functionalities.