Iptycene Quinones: Synthesis and Structure

A practical and efficient method to synthesize iptycene quinones has been developed. As a result,
a series of pentiptycene quinones 8−16 were conveniently synthesized by one-pot reaction of
triptycene quinone 4 or 5 with anthracene 1 or its derivatives 2−3 in refluxing acetic acid in the
presence of p-chloranil, followed by CAN oxidative demethylation. Similarly, a series of heptiptycene
quinones 17−23 with U-shaped cavities were achieved with pentiptycene quinone 10 and triptycene
diquinone 6 as precursors. Non-iptycene triquinones 24 with one tweezer-shaped cavity and 25
with two U-shaped cavities were synthesized by one-pot reactions of anthracene with pentiptycene
triquinones 16a and 16b, respectively. Non-iptycene triquinone 26 with a dendritic structure was
conveniently obtained by the reaction of anthracene with either pentiptycene diquinone 12 or
triptycene triquinone 7. The structures of regioisomers 16a and 16b were determined by the single-crystal structure analysis of 16b. The structures of other regioisomers, including heptiptycene
tetraquinones 19a/19b/19c and heptiptycene triquinones 23a/23b, were identified by comparative
reactions.