Polycycloaddition of terephthalonitrile oxide

Terephthalonitrile oxide (TNO) of various crystalline states was prepared and its structure was studied by infrared spectroscopy, x‐ray diffraction, and hydrolysis. Biscycloadditions of unsaturated compounds such as ethynylbenzene, styrene, benzonitrile, and cyclopentadiene were found to yield 1,4‐bis(5‐phenyl‐3‐isoxazolyl)‐benzene, 1,4‐bis‐(5‐phenyl‐3‐isoxazolinyl)‐benzene, 1,4‐bis‐(5‐phenyl‐1,2,4‐oxadiazolyl)‐benzene, and 1,4‐bis‐(4,5‐cyclopent‐3′‐ene‐3‐isoxazolinyl)‐benzene, respectively. Solution polymerization of TNO gave a polyfuroxan, which had an alternating structure of p ‐phenylene and furoxan rings. Polymerization of TNO in the solid state also gave a polymer, whose structure was postulated as a polyoxazoxime. Copolymerizations of TNO with bifunctional unsaturated compounds such as 1,4‐diethynylbenzene, terephthalonitrile, cyclopentadiene, quinone, and allene yielded 1:1 alternating copolymers containing p ‐phenylene units and corresponding ring structures.