Abstract
The mesoionic compounds have great importance due to their dipolar nature. They are versatile synthons in synthetic chemistry and possess various chemotherapeutic activities. The most important moiety found in mesoionic compounds is the sydnone ring system. Sydnone derivatives have stimulated much interest among synthetic researchers as a result of their unique dipolar, mesoionic character. This ring system is also associated with a wide variety of biological activities. Sydnone derivatives have various applications in synthetic and medicinal chemistry. Sydnones are very useful precursors for selective heterocycles (pyrazoles, imidazoles, oxadiazoles, oxazoles, thiazoles, and tetrazoles), which has also served to initiate research into their functionalization and cycloaddition chemistry, paving the way for stimulated extensive research on the use of sydnones in chemical and industrial applications. So, this review article offers a wide scope of synthesis and applications of sydnone derivatives.