Synthesis of 2‐Aryl‐2,3‐dihydro‐1,8‐naphthyridin‐4(1H)‐ones by Deprotective Cyclization of N‐{3‐[(2E)‐3‐Arylprop‐2‐enoyl]pyridin‐2‐yl}‐2,2‐dimethylpropanamides in Water

Abstract

A new and convenient method for the preparation of 2-aryl-2,3-dihydro-1,8-naphthyridin-4(1H)-ones 4 has been developed. Thus, N-{3-[(2E)-3-arylprop-2-enoyl]pyridin-2-yl}-2,2-dimethylpropanamides 3 are synthesized from commercially available pyridin-2-amine using an easily performed three-step sequence and are subjected to cyclization with deprotection under acidic conditions in H 2 O to give the desired products. Similarly, 2-aryl-2,3-dihydro-1,7-naphthyridin-4 (1H)-ones 8 and 2-aryl-2,3-dihydro-1,6-naphthyridin-4(1H)-ones 12 can be prepared from pyridin-3-amine and pyridin-4-amine, respectively.