Green Synthesis of Aromatic Nitrogen-Containing Heterocycles by Catalytic and Non-Traditional Activation Methods

Recent advances in the environmentally benign synthesis of aromatic N-heterocycles are reviewed, focusing primarily on the application of catalytic methods and non-traditional activation. This account features two main parts: the preparation of single ring N-heterocycles, and their condensed analogs. Both groups include compounds with one, two and more N-atoms. Due to the large number of protocols, this account focuses on providing representative examples to feature the available methods.

Pyrazolines as potential anti-Alzheimer's agents: DFT, molecular docking, enzyme inhibition and pharmacokinetic studies

Alzheimer's disease (AD) is a neurodegenerative disease that is characterized as the main dementia in the elderly. Eighteen pyrazolines were synthesized and evaluated for their inhibitory effects against acetylcholinesterase (AChE) in vitro. Possible interactions between pyrazolines and the enzyme were explored by in silico experiments. Compound 2B of the series was the most active pyrazoline with an IC50 value of 58 nM. Molecular docking studies revealed two important π-π interactions with residues Trp 286 and Tyr 341. A correlation between the HOMO-1 surface and AChE inhibition was observed. ADMET assays demonstrated a good profile for compound 2B. From the abovementioned findings, a new avenue of compound 2B analogues could be explored to develop anti-AD agents.

Recent Advances in the Green Synthesis of Heterocycles: From Building Blocks to Biologically Active Compounds

Recent advances in the environmentally benign synthesis of common heterocycles are described. This account features three main parts; the preparation of non-aromatic heterocycles, one-ring aromatic heterocycles and their condensed analogs. Due to the great variety of and high interest in these compounds, this work focuses on providing representative examples of the preparation of the target compounds.

Synthesis, characterization and spectroscopic behavior of novel 2-oxo-1,4-disubstituted-1,2,5,6-tetrahydrobenzo[h]quinoline-3-carbonitrile dyes

Two synthetic pathways were adopted to synthesize the target 2-oxo-1,4-disubstituted-1,2,5,6-tetrahydro-benzo[h]quinoline-3-carbonitriles. Structure of the synthesized compounds has been characterized based on FT-IR, (1)H NMR, (13)C NMR and elemental analyses. UV-Vis and fluorescence spectroscopy measurements provided that all compounds are good absorbent and fluorescent. Fluorescence polarity study demonstrated that these compounds were sensitive to the polarity of the microenvironment provided by different solvents. In addition, spectroscopic and physicochemical parameters, including singlet absorption, extinction coefficient, Stokes shift, oscillator strength and dipole moment were investigated in order to explore the analytical potential of synthesized compounds.

Synthesis, characterization, electrochemical studies, and in vitro antibacterial activity of novel thiosemicarbazone and its Cu(II), Ni(II), and Co(II) complexes

Metal complexes were prepared by the reaction of thiosemicarbazone with CuCl₂, NiCl₂, CoCl₂, Cu(OAc)₂, Ni(OAc)₂, and Co(OAc)₂. The thiosemicarbazone coordinates to metal through the thionic sulfur and the azomethine nitrogen. The thiosemicarbazone was obtained by the thiosemicarbazide with 3-acetyl-2,5-dimethylthiophene. The identities of these compounds were elucidated by IR, ¹H, ¹³C-NMR, and GC-MS spectroscopic methods and elemental analyses. The antibacterial activity of these compounds was first tested in vitro by the disc diffusion assay against two Gram-positive and two Gram-negative bacteria, and then the minimum inhibitory concentration (MIC) was determined by using chloramphenicol as reference drug. The results showed that compound 1.1 is better inhibitor of both types of tested bacteria as compared to chloramphenicol.