Design, synthesis and characterization of functionalized pyrazole derivatives bearing amide and sulfonamide moieties from aza-aurones

Abstract

In this work, we report the synthesis of new pyrazole derivatives bearing amide and sulfonamide frameworks from aza-aurones. Firstly, the intermediate spiropyrazolines were obtained through a highly regioselective 1,3-dipolar cycloaddition of nitrilimines with aza-aurones. Subsequently, the obtained cycloadducts were subjected to hydrochloric acid in hot ethanol which conducts to 5-(2-aminobenzoyl)-3,4-diaryl-1-phenylpyrazoles. Finally, the target compounds were obtained separately by the action of acetic anhydride, benzoyl chloride and tosyl chloride on the intermediates 2-aminobenzoylpyrazoles, respectively. Structures of all the synthesized compounds were established using IR, 1H NMR and 13C NMR and mass spectroscopy. Synthesis and characterization of novel heterocyclic systems encompassing pyrazole derivatives from aza-aurones are reported. The synthetic routes used in this work are efficient and relevant, involving the 1,3-dipolar cycloaddition and alkylation reactions. The outcomes show that spectroscopic data fit the structure of all synthesized compounds.