Mild and Efficient Synthesis of Polysubstituted Phthalimides and Piperidines Catalyzed by DABCO

Polysubstituted phthalimide derivatives have been isolated in excellent yield from the addition reaction between acetoacetanilide and dialkyl acetylenedicarboxylates by using DABCO as an efficient basic catalyst in EtOH at room temperature. This procedure led to the formation of new phthalimide derivative in the presence of di-tert-butylacetylendicarboxylate as acetylenic ester. The methodology has also been applied successfully for the synthesis of novel piperidine substitutes via the simple reaction between acetoacetanilide and alkyl propiolates. These reactions have some advantages such as not only the process is eco-friendly but also the yields are good and the work-up is simple.