Preparation of polymeric diketones and their conversion to polymeric hydroxy acids in crosslinked polymeric matrices

Abstract

Supports of polystyrene (PS) crosslinked with divinylbenzene (DVB) with varying crosslink densities were prepared and furnished with 1,2-diketo functions through a series of polymer-analogous reactions. Crossed benzoin condensation between polymeric aldehyde (formylated polystyrene) and substituted low-molecular aldehydes gives a set of mixed α-hydroxy ketones. These polymeric benzoin analogues were converted to α-diketones by oxidation. The polymeric systems containing α-diketo functions were subjected to rearrangement under basic conditions into hydroxy acids. The products were characterized by IR and ¹³C CP-MAS NMR spectroscopy and by chemical methods. The rearrangement was observed to be facile in these highly crosslinked networks in spite of the environmental constraints imposed by the rigid and high-molecular-weight polymeric backbone.