This diploma work describes chemical properties of 2H-pyran-2-ones. It goes over types of naturally occurring compounds, with pyranone framework as an isolated structure or fused into a polycyclic compound. It describes bufadienolide, styryl-, 4-hydroxy-, 6-substituted-2H-pyran-2-ones, coumarins and chromones. It addresses the topica of green chemistry. Its principles direct planning of chemical products and processes in such a way as to prevent pollution and decrease negative effects of chemicals on health and environment. Important sources for research of green approaches to activate the reactions are microwave irradiation and use of high pressure. The synthesis of 2H-pyran-2-ones with the application of reactions of condensation, Wittig’s and Baylis‒Hillmans reaction, ring expansion strategy and rearrangement-cyclization, iodolactonization and use of organo or metal catalysts are described. In the experimental part a description of two synthesis, namely of 6-(2-furyl)-3-benzoylamino- and 3-benzoylamino-6-(4-methylphenyl)-2H-pyran-2-one as conducted via ‘one pot’ method developed by Keppe and co-workers, is provided.