SYNTHESIS, CHARACTERIZATION AND BIOLOGICAL STUDIES OF HETEROCYCLIC CHALCONES AND THEIR DERIVATIVES

Abstract

Four series, consisting of sixty (60) new heterocyclic chalcones were synthesized by the condensation of methyl/methoxy substituted formylquinolines with various substituted heteroaromatic ketones. The precursors (formylquinolines) were prepared by Vilsmeier Haack formylation of substituted acetanilides, which in turn were synthesized by N-acetylation of various substituted anilines with the help of acetic acid in the presence of ortho phosphoric acid. Another series of piperidyl-thienyl chalcones was synthesized. For this purpose, the precursor 4-piperidin-1-ylbenzaldehyde was prepared by N- arylation of piperidine with 4-fluorobenzaldehyde in the presence of K2CO3 and a phase transfer catalyst CTAB in DMF solvent. The 4-piperidin-1-ylbenzaldehyde was then condensed with various thienyl ketones in alkaline medium with constant stirring at room temperature to give the fifth series consisting of twelve (12) new chalcones. The ketoethylinic group of chalcones was then cyclized into 2-pyrazolines by refluxing them with hydrazine hydrate in ethanolic solution. In this way fifty six (56) new pyrazoline derivatives of chalcones were obtained. Finally all of the synthesized compounds (128 in number) were screened for their antibacterial, antifungal, antileishmanial, anti-HIV-1 and cytotoxic activities. Many of the prepared chalcones as well as their 2-pyrazoline derivatives were proved to be potent biologically active compounds.