1.2.4- Oxadiazoles Materials chemistry

This review is an overview on the recent literature on 1,2,4-oxadiazole s chemistry and its major advances since the last reviews on this topic (2008MI243, 2009OBC4337). After a brief historical introduction and a general presentation of the main features of this heterocycle, modem synthetic methodologies will be presented together with recent mechanistic interpretations of 1,2,4-oxadiazoles thermal and photochemical reactivity. As for appHcations, the main fields of Hfe sciences and materials chemistry have been considered. A commentary on future prospects adds suggestions for further developments of 1,2,4-oxadiazole heterocycles. 

Due to the peculiar features introduced by fluorinated moieties, the synthesis, the reactivity, and the appUcation of fluorinated oxadiazoles and thiadiazoles still are challenging research topics. Therefore, the updated synthetic guidelines reported in this chapter will represent a useful tool for both the experienced synthetic chemists and those willing to embrace the study of fluorinated azoles. For this reason, it is the authors opinion that synthetic information organized by kind of heterocycle is better approached by the reader for faster consultation. On the other hand, reactivity has been presented by focusing on the type and position of the fluorinated moiety, in the attempt to provide general concepts transferable also to other heterocycUc systems. Finally, examples of fluorinated oxadiazoles and thiadiazoles used in materials chemistry or as bioactive compounds have been briefly illustrated to suggest the potential application of newly synthesized compounds. 

Sun, M., Xin, H., Wang, K.Z., et al. (2003) Bright and monochromic red light-emitting electroluminescence devices based on a new multifunctional europium ternary complex. Chemical Communications, 702-703. Liang, L.S., Zhou, Q.G, Cheng, Y.X., and Wang, L.X. (2003) Oxadiazole-functionalized europium(III) P-diketonate complex for efficient red electroluminescence. Chemistry of Materials, 15, 1935-1937. 

Oxadiazoles experienced an almost 80-year long period of scientific lethargy before they tickled the curiosity of chemists. The study of chemical and photochemical reactivity of 1,2,4-oxadiazoles opened the way to a series of applications in heterocyclic synthesis. Today, 1,2,4-oxadiazoles are known in medicinal chemistry for their use as bioisosters of esters and amides. Furthermore, fluorinated 1,2,4-oxadiazoles have been applied in materials science either by themselves or for the targeted modification of polymers and macromolecules. Overall, the synthesis of... 

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