Activation of 6-bromoquinoline by nitration: synthesis of morpholinyl and piperazinyl quinolines

Quinoline forms the key skeletal component of a number of important natural products and pharmacologically-active compounds. Despite a tremendous amount of research pertaining to the derivatization of quinoline, very few general synthetic routes are described in the literature starting from quinoline or tetrahydroquinoline. A simple and convenient method for the polyfunctionalization of quinolines via nitration of bromoquinolines has been developed. This method represents a new synthetic approach to convert brominated nitroquinoline derivatives into useful cyclic amines via nucleophilic-substitution (SNAr) reaction.