Improved Syntheses of Halogenated Benzene-1,2,3,4-Tetracarboxylic Diimides

The preparation of halogenated benzene-1,2,3,4-tetracarboxylic
diimide derivatives is challenging because of the possibility of competitive
incorrect cyclizations and SNAr reactivity. Here, we demonstrate
that bypassing traditional cyclic anhydrides and instead directly
reacting dihalobenzene-1,2,3,4-tetracarboxylic acids with primary
amines in acetic acid solvent successfully provides a range of desirable ortho-diimide products in good yields. Furthermore, we demonstrate
that sterically challenging N-derivatizations can
be readily achieved under microwave reactor conditions. The halogenated
diimides described here are attractive building blocks for organic
materials chemistry.