The reactivity of various activated olefins towards the [3 + 2] annulation with hydrazones (aza-enamines) has been studied. Nitroolefins, methyl vinyl ketone, acrylates and acrylamide were found to react with aldehyde hydrazones of different electronic nature to generate 1,3,5-/1,3,4-trisubstituted pyrazoles selectively. A detailed optimization study was conducted to derive the best condition for the annulation reaction of different olefin partner and the intermediate dihydropyrazole is also identified. Recently, metal-free routes for pyrazoles were reported by Ueda et al [18] and Ma et al. in an effective manner. Very recently Zhu et al (2021) reported the synthesis of 5-trifluorometh-[a]
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