A study of some quinolizone derivatives

The condensation of methyl 2‐pyridylacetate and ethyl phenylpropiolate has been found to be a simple and convenient method for the preparation of 4‐quinolizone derivatives. Upon hydrolysis and decarboxylation, the initial condensation product, l‐carbethoxy‐2‐phenyl‐4H‐quinolizin‐4‐one (V) was converted to 2‐phenyl‐4 H ‐quinolizin‐4‐one (VII). Nitration and bromination of these quinolizones were affected under mild conditions. Nitration of V displaced the carbethoxy group, while bromination did not and 1,3‐dinitro‐4 H ‐quinolizin‐4‐one and 1‐carbeth‐oxy‐2‐phenyl‐3‐bromo‐4 H ‐quinolizin‐4‐one were obtained, respectively.