Use of ?-(N,N-dialkylamino)Propiophenones in the Synthesis of Nitrogenated Heterocyclic Compounds

β-(N,N-dialkylamino)propiophenones (ArCOCHR1CH2NR2) are compounds with special synthetic interest not only because many of them are biologically active, but also because they posses two different electrophilic reaction centers (i. e. carbonyl group and the β-carbon atom), which can be attacked by ambifunctional nucleophilic reagents. This property makes them attractive starting materials in medicinal chemistry as valuable building blocks for ring closure reactions to form mainly five, six and seven-membered heterocyclic compounds. Additionally, the presence of α-methylene active hydrogen atoms in such compounds also opens new possibilities for ring closure reaction as recently has been published. A selection of representative examples about structural and biological properties of the title compounds, synthetic methods and ring closure reactions leading to nitrogenated heterocyclic systems are described in this review.