2‐Pyrazolin‐5‐One‐Based Heterocycles: Synthesis and Characterization

A novel series of pyrazoline and thiazole derivatives incorporating 2‐pyrazolin‐5‐one moiety were synthesized starting from α,β‐unsaturated ketones under the effect of hydrazine derivatives and thiosemicarbazide. The obtained pyrazolines 4a , 4b were treated with different reagents to afford N ‐substituted pyrazolines 5a , 5b , 6a , 6b , 7a , 7b , 8a , 8b . N ‐Thiocarbamoyl pyrazolines 12a , 12b were cyclized using phenacyl bromide, 2,3‐dichloroquinoxaline, and monochloroacetic acid afforded the novel pyrazolinyl thiazoles 13a , 13b , 14a , 14b , 15a , 15b , 16a , 16b , 16c , 16d , 16e , 16f . The newly synthesized compounds were characterized by analytical and spectral data.