Cyclization of chalcone with hydrazine is a well established reaction. I've done the synthesis of pyrazolines using chalcone, formic acid( or acetic acid) and hydrazine with good yield.
Hydroxyl amine/semicarbazide/urea/thiosemicarbazide/phenyl hydrazine can also be used to synthesize respective pyrazoles.
Article Chalcones: Versatile Intermediates in Heterocyclic Synthesis
This article deals with carbazides and using sulfamic acid as catalyst :
Oxidative Cyclization of Chalcones in the Presence of Sulfamic Acid as Catalyst. Synthesis, Biological Activity, and Thermal Properties of 1,3,5-Trisubstituted Pyrazoles
- J. D. Bhirud/ G. R. Gupta
- & H. P. Narkhede
Russian Journal of Organic Chemistry volume 56, pages1815–1822 (2020)
My team have done cyclization of chalcone using NaOH l Ethanol and reflux.
Isoxazolines or isoxazoles can also be prepared by condensation of chalcones with hydroxylamine :
CYCLIZATION OF CHALCONES TO ISOXAZOLE AND PYRAZOLE DERIVATIVES
Chemistry of Heterocyclic Compounds, Vol. 45, No. 12, 2009.
You can use thionyl chloride for cyclization and yield can be increased up to 80-85%. . During the course of reaction the acidic SOCl2 catalyses for the cycloaddition reaction between chalcone and hydrazine hydrate. The catalyst SOCl2 abstracts water and it produce H+ and Cl- ions in-situ from the hydrazine hydrate. The hydrazine molecule attacks the carbonyl carbon of the chalcones and further rearranges leads to the formation of pyrazoline molecule.
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