Facile Synthesis of 4-Oxo-4<i>H</i>-quinolizine-2-carboxamide Derivatives

<div><p></p><p>A facile synthetic method for the construction of 2-substituted-4-oxo-4H-quinolizine based core structure has been successfully developed. The synthesis made use of a one pot Stobbe condensation followed by cyclisation starting from the commercially available 2-pyridinecarbaldehyde. The structure of the formed 4-oxo-4H-quinolizine-2-carboxylate was fully confirmed by MS, ¹H NMR, ¹³C NMR, COSY, HMBC and HSQC spectra. The ethyl carboxylate moiety was then further functionalized via direct aminolysis by a range of amines to afford the corresponding 4-oxo-4H-quinolizine-2-carboxamides <b>4a-i</b> in moderate to good yields.</p></div