Metal‐Free Synthesis of Highly Diversified Pyrazole C‐3/4/5 Tethered 1,3,4‐Oxadiazoles and Their Photophysical Assessment

Abstract

A robust, metal‐free and K2CO3‐mediated method has been developed to access highly diversified pyrazole C‐3/4/5 linked 1,3,4‐oxadiazole derivatives through the formation of C‐O/C‐N bonds in a one‐pot operation. This domino methodology was facilitated by utilizing pyrazole C‐3/4/5 carbaldehydes and benzohydrazides as starting substrates to generate the interesting molecular hybrids with high yields. The photophysical properties were also evaluated of the synthesized derivatives and exhibited good results with more than seven parameters. The fluorescence quantum yield of the pyrazole based 1,3,4‐oxadiazole was reached up to 75%. The salient features of this approach are diversity‐oriented synthesis, metal‐free strategy, high yields and superior atom economy.