Two alternative procedures, both starting from easily accessible tetramethylanthracenes and employing the Diels-Alder addition as the key reaction step(s), have been examined in the synthesis of the title compounds.We are interested in the synthesis of high-symmetry aromatic oligocarboxylic acids and their supramolecular selfassembly. 1 As a part of this long-standing program, we have focused our attention on the triptycene analogues of phthalic and terephthalic acids, which, owing to the unique geometry of the triptycene skeleton, are expected to find versatile application in molecular tectonics and possibly also in molecular electronics. 2 In this paper, we wish to report two alternative procedures for synthesis of the target acids, both starting from easily accessible tetramethylanthracenes and exploiting the Diels-Alder addition as the key reaction step(s).In the first procedure (Scheme 1), tetramethylanthracenes 1 and 4 undergo Diels-Alder reaction with an aryne 3 genScheme 1 Reagents and conditions: (a) anthranilic acid or 3,6-dimethylanthranilic acid, isoamyl nitrite, 1,2-dichloroethane, THF, reflux, 7 h; (b) KMnO 4 , pyridine, H 2 O, reflux, 24 h; then aq 3 M HCl; (c) anthranilic acid or 4,5-dimethylanthranilic acid, isoamyl nitrite, 1,2-dichloroethane, THF (diglyme), reflux (95°C), 7 h; (d) KMnO 4 , pyridine, H 2 O, reflux, 24 h; then aq 3 M HCl.
