Thermosetting quinazolone resins, their preparation, and their use
Résumé
The quinazolones I (Ar1 = mono- or polycyclic arylene, optionally alkyl-substituted; Ar2 = polynuclear, carbocyclic or heterocyclic, divalent arom. group) have softening points sufficiently low that polymn. of the ethynyl groups begins in the molten state. Adding 2.45 g Me3SiCCH dropwise to 6.04 g 2-(4-bromophenyl)-1,3-benxoxazin-4-one, 25 mg Pd(OAc)2, 50 mg Ph3P, 80 mL THF, and 20 mL Et3N and allowing the reaction to proceed for 8 h gave 65% 2-[4-[(trimethylsilyl)ethynyl]phenyl]-1,3-benxoazin-4-one (II). Heating 8.85 g II, 3.87 g 2,6-bis(3-aminophenoxy)pyridine, and 4.5 g (PhO)3P in 20 mL pyridine at 100 for 10 h and removing trimethylsilyl groups gave 65% 3,3'-(2,6-pyridinediyldioxydi-1,3-phenylene)bis[2-(4-ethynylphenyl)-4-quinazolone] (III). Heating III at 230 for 2 h and 320 for 1 h gave a polymer with glass temp. 290