Synthesis and Characterization of Novel Cyclic (Aryl Ether Ketone)s, Cyclic (Aryl Ether Phthalazine)s, and Cyclic (Aryl Ether Isoquinoline)s

Abstract

The efficient preparation of a range of cyclic (aryl ether ketone)s containing the 1,2-dibenzoylbenzene moiety via the nucleophilic aromatic substitution route with the use of the pseudo-high dilution principle was developed. Chemical transformation of the 1,2-dibenzoylbenzene moiety of these cyclic (aryl ether ketone)s led to the preparation of novel cyclic (aryl ether phthalazine)s and cyclic (aryl ether isoquinoline)s. The preparation of cyclic (aryl ether ketone)s from 4,4'-difluorobenzophenone and 1,3-bis(4-fluorobenzoyl)benzene is also discussed. Detailed structural characterization of these novel oligomers by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS), 13 C and 1 H NMR, GPC, and HPLC confirmed the cyclic nature and revealed the composition of the oligomeric mixtures prepared. MALDI-TOF-MS, which enables the detection of oligomers with mass up to 5000 Da, was shown to be a very powerful tool for the analysis and proof of the cyclic nature of the oligomers. Thermoanalyses show that most of these oligomers exhibit a high degree of crystallinity while their corresponding polymers are amorphous.