Synthesis of heterocyclic monomers via Reissert chemistry

Abstract

AbstractThe chemistry of Reissert compounds has been used to synthesize activated difluorotetraketone monomers containing two coupled isoquinolyl moieties, linked at either the 1,1′‐ or 4,4′‐positions. These monomers offer routes to novel families of poly(heteroarylene ether)s. New 4,4′‐coupled bis(Reissert compound) 9 containing 4,4′‐diketo moieties failed to afford the desired difluorotetraketo monomer upon attempted rearrangement. However, analogous bis(Reissert compound) 19 containing 4,4′‐dibenzyl units did so, via aldehyde condensation, hydrolysis of the intermediate ester and oxidation of the four benzylic moieties to keto groups; thus the novel difluorotetraketone monomer 10 was prepared. Novel bis(Reissert compound)s 24, 28, and 35 were synthesized from diacid chlorides and 4‐(p‐fluorobenzyl)isoquinoline. Rearrangement of 24 to the diketone 29, followed by oxidation of the 4‐benzyl moieties resulted in difluorotetraketone monomer 30 containing a 1,1′‐linked bisisoquinoline. The 1,1′‐linked bis(isoquinolylfluorodiketo) monomer 38, isomeric with 10, was prepared from 4‐(p‐fluorobenzyl) Reissert compound 36 by condensation with terephthaldehyde, ester hydrolysis to diol 37, and oxidation. In the course of this effort, a number of new isoquinoline Reissert compounds were synthesized as model systems. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3856–3867, 2010