Efficient Bromination of Naphthalene Dianhydride and Microwave-Assisted Synthesis of Core-Brominated Naphthalene Diimides

This article presents an efficient method for the synthesis of core-brominated naphthalene diimides (NDI) from naphthalene dianhydride (NDA). A procedure for monitoring the NDA bromination reaction by 1H NMR spectroscopy is described, allowing for optimization and greater consistency of this reaction. Furthermore, the subsequent bis-imidization reaction of the brominated NDA product has been significantly enhanced using microwave-assisted conditions, with recovery of pure product via simple filtration in excess of 90% of theoretical yield. This chemistry offers greatly improved methodology for obtaining core-substituted NDI compounds with high efficiency and good yields.