Synthesis of some novel ethyl 5-methyl-6-cyano-7-substituted-2-oxo-2<i>H</i>-pyrano [2, 3-<i>b</i>] pyridine-3-carboxylate derivatives

Abstract

Ethyl 5-methyl-6-cyano-7-substituted-2-oxo-2<i>H</i>-pyrano[2, 3-<i>b</i>]pyridine-3-carboxylates <b style="">4a-j</b> have been prepared starting from 2, 6-dihyroxy-3-cyano-4-methyl pyridine <b style="">1</b>. The compound <b style="">1</b> reacts with <i>N</i>,<i>N</i>-dimethylaminoethylenemalonate in acetic acid under reflux conditions to give 5-methyl-6-cyano-7-hydroxy -2<i>H</i>-pyrano[2,3-<i>b</i>]pyridine-2-one <b style="">2</b>, which is further treated with phosphorous oxychloride to obtain ethyl 5-methyl-6-cyano-7-chloro-2-oxo-2<i>H</i>-pyrano[2,3-<i>b</i>]pyridine-3-carboxylate<b style=""> 3</b>. This chloride derivative <b style="">3</b> is finally converted to various amino derivatives <b style="">4a-j</b> by condensation with corresponding amines. These compounds are expected to have antihypertensive activity.