Synthesis and bromination of 4-alkylamino-N-alkyl-1,8-naphthalimides

4-Alkylamino-N-alkyl-1,8-naphthalimides were prepared from 4-chloro-1,8-naphthalic anhydride and from 4-amino-1,8-naphthalimide. It was found that the amino nitrogen of 4-amino-N-alkyl-1,8-naphthalimides is nucleophilic enough to participate in nucleophilic displacement reactions without the need for added base, despite being a vinylogous amide. Bromination of 4-alkylamino-N-alkyl-1,8-naphthalimides using molecular bromine was found to occur in the absence of a Lewis acid catalyst, and to be regiospecific, yielding only the 3-bromo isomer. Extended reaction times and the use of excess bromine result in dealkylation of the 4-alkylamino substituent, but no polybromination of the naphthalimide ring system. (C) 1999 Elsevier Science Ltd. All rights reserved.