No abstract

The synthesis of chalcone has drawn tremendous interest over the past years due to its wide applications in the pharmaceutical and biological sectors. Indeed, this compound is reported to possess a broad spectrum of promising bioactivities, including anti-inflammatory, anti-invasive, antioxidant, antitumor and antibacterial properties. In this work, chalcone 3 was synthesised via Claisen-Schmidt condensation by using a common starting material of benzaldehyde 1 and acetophenone 2 in the presence of alcoholic alkaline base. Subsequently, 3,5-diphenyl-2-pyrazoline 4 intermediate was successfully synthesised by reductive amination reaction of 3 with hydrazine hydrate. Thereafter, insertion of acyl subunit at N-1 position of the corresponding amine via 1N-acylation reaction afforded the targeted 1-acetyl-3,5-diphenyl-1H-pyrazole 5 derivative. The structures of all the synthesised compounds were confirmed by elemental analyses, IR, GC-MS and NMR spectra.

A facile synthesis of novel 1-substituted β-carboline derivatives by using three efficient reaction steps was described. The synthetic route began with the construction of β-carboline frameworks involving the coupling of 5-hydroxy-L-tryptophan with different substituted phenylglyoxal via Pictet-Spengler condensation. Subsequent reduction of carbonyl functionality on carbon-7’ by using Wolff-Kishner reaction followed by N-alkylation afforded a practical access to a series of 1-substituted β-carboline derivatives in moderate yields. These novel derivatives were successfully synthesized without the use of expensive metal catalyst, prolonged reaction hours or critical reaction conditions. The molecular structures of all synthesized derivatives were confirmed by infrared (IR), gas chromatography–mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) spectroscopy.

5-benzylpyrrolidine-2,4-dione 9 are versatile scaffolds with a unique structural feature responsible for the diversity of its biological importance. Over the past years, many researchers have reported the synthesis of various bio-active (S)-5-benzylpyrrolidine-2,4-dione derivatives due to its simplicity yet exhibiting promising bioactivities. This review focuses on the synthesis of core structure 9 and its derivatives based on the substitution at carbon-3 position of (S)-5-benzylpyrrolidine-2,4-dione 9. This review also reported the effective method for the synthesis of core structure 9 with 98% yield. Biological evaluations of various prepared derivatives by various researchers were described.