Synthesis, odor characteristics and biological evaluation of N-substituted pyrrolyl chalcones

Abstract

A novel approach for converting N-substituted acetylpyrroles and primary alcohols into N-substituted pyrrolyl chalcones in air with the assistance of t-BuOK is reported, and several prominent flavor and bioactive molecules were obtained. The process entails oxidizing the alcohols to the corresponding aldehydes, and t-BuOK is crucial to the effective production of CC bonds by aldol condensation. Gas chromatography-mass spectrometry-olfactometry (GC-MS-O) was used to examine the odor properties of pyrrolyl chalcones, which are usually different from those of the associated acetylpyrroles and alcohols. The biological evaluation assay showed that the products (E)-3-(3-fluorophenyl)-1-(1-methyl-1H-pyrrol-2-yl)prop-2-en-1-one (3j), (E)-1-(1-ethyl-1H-pyrrol-2-yl)-3-phenylprop-2-en-1-one (4a), (E)-3-(4-bromophenyl)-1-(1-ethyl-1H-pyrrol-2-yl)prop-2-en-1-one (4e), (E)-3-(4-chlorophenyl)-1-(1-ethyl-1H-pyrrol-2-yl)prop-2-en-1-one (4f) and (E)-1-(1-ethyl-1H-pyrrol-2-yl)-3-(4-fluorophenyl)prop-2-en-1-one (4g) exhibited excellent inhibitory activity against R. solani with EC₅₀ values from 0.0107 to 0.0134 mg mL⁻¹. Molecular docking of 3j with SDH (succinate dehydrogenase) was performed to reveal the binding modes in the active pocket and analyze the interactions between the molecules and the SDH protein. Meanwhile, they have good thermal stability according to the results of thermogravimetry (TG) analysis.