Benzonaphthyridines from Morita-Baylis-Hillman Adduct Acetates

quinolines - Baylis-Hillman reaction - Morita-Baylis-Hillman reaction - heterocycles - benzonaphthyridines

Significance

<P>In this contribution the authors report the synthesis of benzonaphthyridines from Morita-Baylis-Hillman adduct acetates via an amine condensation-cyclization process. Importantly, the authors show that increasing the equivalents of amine leads to more substituted products via a 1,4-addition process. Additionally, careful control of reaction time and temperature provides access to a range of 1,2-dihydrobenzo-naphthyridines.</P>

Comment

<P>Benzonaphthyridines have found uses in materials due to their fluorescent and electroluminescent properties. This method allows access to multiple addition products and oxidation states from readily available starting materials under mild environmentally benign reaction conditions. The possibility of accessing more complex heterocyclic systems could be realized by expanding the methodology to allow for iterative annulation.</P>