Facile synthesis and controllable bromination of asymmetrical intermediates of perylene monoanhydride/monoimide diester

Dibutyl-perylene-3,4-anhydride-9,10-dicarbonylate (1) as an asymmetrical intermediate was synthesized in 80% yield by precipitation of the less soluble target molecule, which was formed through acidic hydrolysis of tetraesters of perylene tetracarboxylic acids at one side in a mixed solvent system. Based on the intermediate, two other asymmetrical intermediates 2 and 3 with monoimide group were also synthesized in high yields. The mono-bromination and di-bromination of 3 typical intermediates could be controlled by using different bromine concentration. The chemical structures of the brominated products and ratios of their isomers were confirmed directly or deduced from their phenol substituted products with MS and NMR spectra. The bromination of the intermediates mainly afforded isomers, but intermediates 1 and 2 could afford unique di-brominated product and mono-brominated product respectively. The bromination of the intermediates led to only slight changes in absorption spectra, but relatively obvious changes in emission spectra.