Synthesis and characterization of some pyrazolines derived from naproxen and evaluation of their biological activity

In this work, some of heterocyclic compounds derived from naproxen acid were prepared and characterized, and their biological activity was evaluated. Naproxen acid chloride (N₃) was prepared by the reaction of naproxen acid with thionyl chloride in chloroform and then reacted directly with p-amino acetophenone in presence of (DCM) to form naproxen amide (N₄). The chalcones (A) (N₅-N₈) were prepared by the reaction of some aromatic aldehydes with naproxen amide (N₄). other chalcones (B) N₉-N₁₀ and (C) N12-N₁₃ had prepared by the reaction of some aromatic aldehydes with acetophenone and 2-acetylpyridine respectively. Then naproxen ethyl ester (N₁) was prepared by reaction of absolute ethanol with naproxen acid. The ester was converted to naproxen acid hydrazide (N₂) by refluxing it with hydrazine hydrate 80%. The last step involved converting chalcones (A), (B) and (C) to pyrazolines (N₁₅,N₁₅), (N₁₆,N₁₈) and (N₁₉,N₂₀) respectively. The prepared compounds were identified with some of physical properties and available spectroscopy methods. Eventually the biological activity of the prepared compounds was evaluated against two types of bacteria: Staphylococcus and Escherichia coli. It was found that some of these compounds showed characteristic activity against these types of bacteria.