Synthesis of 3-(4´´ -Substituted Phenyl)-5-(4´-Substituted Phenyl)- Δ2-Pyrazolines and Their Derivatives

Abstract

4-Substituted acetophenone (Ia–b) condenses with substituted

benzaldehyde in ethanol in presence of pulverised KOH to give

4-substituted chalcone and 4´-substituted chalcone (IIa–d); (IIa–d)

react with hydrazine hydrate in ethanol to give pyrazolines (IIIa–d).

Pyrazolines (IIIa–d) react with acetic acid to form 1-acetyl pyrazoline

(IVa–d), pyrazoline reacts with benzoyl chloride in pyridine

to give 1-benzoyl pyrazoline (Va–d). Also pyrazoline reacts with

sodium nitrite to give 1-nitroso pyrazoline (VIa–d). Characterisation

and structural elucidation were done on the basis of

chemical, analytical and spectral analysis.