7-Amino-2-pyrenecarboxylic Acid

Pyrenes undergo initial electrophilic substitution in the 1 position; a second substitution typically occurs in the 3, 6, or 8 positions. We sought a pyrene with synthetically useful handles in the unusual 2,7 substitution pattern. To that end, 7-amino-2-pyrenecarboxylic acid was prepared by partial reduction of pyrene to 4,5,9,10-tetrahydropyrene, Friedel−Crafts acylation in the 2 position, and conversion to 2-carbethoxytetrahydropyrene through the haloform reaction and esterification. Nitration of the ester proceeded in the 7 position; rearomatization, reduction of the nitro group, and saponification gave the title compound.