Synthesis of 3,5-Disubsituted Pyrazolines and their Derivatives

A. V. Ingle¹, A. G. Doshi² and A. W. Raut³

¹Department of Chemistry, Yeshwantrao Chavan College of Arts, Commerce & Science Sillod, Dist. Aurangabad - 471 112 (India). ²Vidya Bharati Mahavidyalaya, Amravati - 444 602 (India). ³P.G. Department of Chemistry, Shri Shivaji Science College, Amravati - 444 603 (India).

2-Acetylthiophene condenses with different aromatic aldehyde in ethanol in the presence of aqueous NaOH to give 1-(2’-thienyl)-3-(substituted phenyl) -2- propen-1-one (Ia-e) which reacts with hydrazine hydrate in ethanol to give pyrazoline (IIa-e). Similarly, 1-(2’-thienyl)-3-(substituted phenyl)-2-propen-1-one (Ia-e) reacts with phenyl hydrazine hydrochloride in the presence of ethanol medium and 1,2 drops of NaOH (2N) to give 1-phenyl pyrazoline (IIIa-e), (Ia-e) Reacts with 2,4-dinitro phenyl hydrazine in presence of ethanol medium to give 1-(2,4-dinitro phenyl) pyrazoline (IVa-e) and also reacts with semicarbazide hydrochloride in presence of ethanol medium and 1,2 drops of NaOH (2N) to give 1- carboxamido pyrazoline (Va-e). Pyrazoline (IIa-e) reacts with acetic acid to give 1–acetyl pyrazoline (VIa-e), as well as it reacts with benzoyl chloride in pyridine medium to give 1-benzoyl pyrazoline (VIIa-e) and also reacts with 1:1 HCl and 10% sodium nitrite to give 1-nitrso pyrazoline (VIIIa-e). Characterization and structural elucidation were done on the basis of melting points determination, analytical and spectral studies.

Chalcone and pyrazolines; synthesis; structural study