Azole analogues of polypyromellitimides

Rigid-rod polymers. 1. Synthesis and thermal properties of para-aromatic polymers with 2,6-benzobisoxazole units in the main chain

“…4-(Pentaphenylphenyl)benzoic acid (11). A mixture of tetraphenylcyclopentadienone (5.0 g, 13 mmol), p-(phenylethynyl)benzoic acid18 (5.5 g, 25 mmol), and benzophenone (25 g) was heated at reflux (305 °C) for 30 min.…”