A New Approach to the Synthesis of Benzo[c][1,7]naphthyridin-4(3H)-ones

Alexander S. Fisyuk, Ivan V. Kulakov, Anton L. Shatsauskas, Mariya V. Matsukevich, Irina V. Palamarchuk, Т. М. Сейлханов, Yu. V. Gatilov

2017

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DOI 10.1055/s-0036-1590470

Data confidence 70 medium

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Abstract

A simple and efficient approach has been developed for the synthesis of previously inaccessible 6-arylbenzo[c][1,7]naphthyridin-4(3H)-ones, which is based on the interaction of 3-amino-6-methyl-4-arylpyridin-2(1H)-ones and aromatic aldehydes in a strong acidic media (trifluoroacetic, phosphorous or polyphosphorous acids) under heating. The initial imine derivatives undergo Pictet–Spengler condensation to form intermediate 6-aryl-5,6-dihydrobenzo[c]-1,7-naphthyridin-4(3H)-ones, which are oxidized by atmospheric oxygen to give 3-amino-6-methyl-4-arylpyridin-2(1H)-ones as the final products.