Search and research of biologically active medicinal substances. Five- and six-membered heterocyclic compounds and their derivatives possess great potential for the synthesis of new biologically active compounds. They are involved in important biochemical processes that take place in the living organisms, thus ensuring normal vital functions. Synthetic thiazole derivatives with a broad spectrum of biological activity are of particular importance. They show a broad spectrum of biological properties. Many biologically active compounds contain a β-alanine moiety, which allows them to be used in the development of pharmaceutically important preparations. We used widely N-substituted-β-amino acids for the synthesis of azetidine, quinoline, imidazole, pyridine derivatives.