5,6,7,8-Tetrahydroquinolines. Part I. A novel synthesis of 7,8-dihydroquinolin-5(6H)-ones

Abstract

The reaction of alkyl-substituted cyclohexane-1,3-diones with β-amino-αβ-unsaturated aldehydes or ketones (R¹CO·CR³:CR²·NH₂) and, conversely, the reaction of alkyl-substituted 3-aminocyclohex-2-enones with β-ethoxy-αβ-unsaturated aldehydes or ketones (R¹CO·CR³:CR²·OEt) gives 2-, 3-, and 4-substituted 7,8-dihydroquinolin-5(6H)-ones which can be readily reduced to the corresponding 5,6,7,8-tetrahydroquinolines.