DIELS-ALDER POLYMERIZATIONS .6. PHENYLATED POLYPHENYLENES FROM BIS-2-PYRONES AND P-DIETHYNYLBENZENE

Phenylated polyphenylenes (10, 11) were obtained from the reactions of p-diethynylbenzene with 5,5ʹ-p-phenylenebis-4,6-diphenyl-2-pyrone (4) or 6,6ʹ-p-phenylenebis-4,5-diphenyl-2-pyrone (5), respectively, at 210-300° in toluene. The low molecular weight polymers ([n] = 0.04-0.13) obtained showed approximately the same thermal stability (TGA break = 550°, air or nitrogen) as those high molecular weight polyphenylenes obtained from the reaction of diethynylbenzenes with bistetracyclones. The polymer backbones probably have both meta and para linkages in 10 and ortho and meta linkages in 11 as demonstrated by the model reaction of 4,5,6-triphenyl-2-pyrone (7) with phenylacetylene which affords a 5:1 mixture of 1,2,3,4-tetraphenylbenzene (8) and 1,2,3,5-tetraphenylbenzene (9). © 1969, American Chemical Society. All rights reserved.