Synthesis of Some N-Formyl Pyrazoline Derivatives

Abstract

Synthesis of six N-formylpyrazolines was completed through applying and adjusting a reaction between their corresponding chalcones and hydrazine hydrate. While the six chalcones were synthesized via Claisen-Schmidt Condensation (CSC) reaction. The completion of the synthesis was proved by characterization of the products. Basically the synthetic design of these compounds applied through the retrosynthetic analysis concepts and disconnection approach technique. The structures of the chalcones and N-formylpyrazolines were identified by examining their physiochemical properties and their spectral features. The interpretation of the results demonstrated that these products have the expected structures. Whereas λmax values and the observed colors of these compounds indicated of the presence of conjugated unsaturated system, IR spectrums showed existence of (C=O) in conjugation system with (C=C) in chalcones and (Aldehydic C=O), (C=N), (C-N) and (Aliphatic C-H) in N-formylpyrazoline derivatives and the aromatic rings bands served as fingerprint of these compounds and the (1H, 13C) -NMR spectral revealed a set of signals that confirmed their suggested structures. The agreement between the results of these different techniques investigated and removed a doubt of their final identity. Anti-bacterial activity of all synthesized compounds was assessed by measuring their inhibition zone diameter and all of them showed an activity against Gram positive (S.aures) and Gram negative (E.coli) bacteria.