Facile Synthesis of 1-Hydroxy-5-methoxy-Benzo[f][2,7]naphthyridines

Abstract

A new route for the synthesis of 1-hydroxy-5-methoxy-benzo[f][2,7]naphthyridines has been developed from easily available precursor 2-chloro-3-formyl quinolines. The 2-methoxy-3-formyl quinolines were prepared and condensed with glycine ethyl ester hydrochloride. This resulted in the formation of an imines, which on cyclization with Dowtherm A yielded 1-hydroxy-5-methoxy-1,2-dihydrobenzo[f][2,7]naphthyridines.

Keywords:

• Benzonaphthyridines
• Dowtherm A cyclization
• formylquinolines
• glycine ethyl ester hydrochloride

ACKNOWLEDGMENTS

The authors thank the sophisticated instrumentation faculty at the Indian Institute of Science, Banglore, for recording the ¹H and ¹³C NMR spectra, and National Institute for Interdisciplinary Science and Technology (NIIST), Council of Scientific & Industrial Research, India, Thiruvananthapuram, for recording the mass spectra.