2-Pyrazoline core is a very interesting five-membered heterocycle, which has been explored in recent years due to its vast applications as the core structure of bioactive and industrial agents. Based on literature studies, versatile synthetic approaches have been employed for the preparation of 2pyrazolines, among them the reaction between hydrazines and α,β-unsaturated enones as the most used method. In this review article, different methods for the synthesis of 2-pyrazolines using hydrazine derivatives were classified and presented.Initially, numerous catalytic methods for the preparation of 2pyrazolines from hydrazines and α,β-unsaturated enones are reviewed and various aspects of these methods discussed including catalyst efficiency, catalyst recovery, green chemistry, cost-effectiveness, scope of the method, enantioselectivity, and yield. In addition, reactions between hydrazines and other reagents in multicomponent and two-component reactions, developed recently, are discussed. Finally, some of the important applications of 2-pyrazolines are summarized.
A new series of 1,3,5‐trisubstituted 2‐pyrazolines for the inhibition of cyclooxygenase‐2 (COX‐2) were synthesized. The designed structures include a COX‐2 pharmacophore SO2CH3 at the para‐position of the phenyl ring located at C‐5 of a pyrazoline scaffold. The synthesized compounds were tested for in vitro COX‐1/COX‐2 inhibition and cell toxicity against human colorectal adenocarcinoma cell lines HT‐29. The lead compound (4‐chlorophenyl){5‐[4‐(methanesulfonyl)phenyl]‐3‐phenyl‐4,5‐dihydro‐1H‐pyrazol‐1‐yl}methanone (16) showed significant COX‐2 inhibition (IC50=0.05±0.01 μM), and antiproliferative activity (IC50=5.46±4.71 μM). Molecular docking studies showed that new pyrazoline‐based compounds interact via multiple hydrophobic and hydrogen‐bond interactions with key binding site residues of the COX‐2 enzyme.
Chromium(III) chloride mediates DNA-DNA cross-linking. Some chromium complexes promote programmed cell death in specific ligand environment through binding to DNA. One strategy that can be supposed for reduction of Cr binding affinity to DNA is using curcumin as a chelator. In the current study, the [Cr(Curcumin)(EtOH)](NO) (CCC) was synthesized and characterized by UV/Vis, FT-IR, CHN and spectrophotometric titration techniques. The mole ratio plot revealed a 1:1 complex between Cr and curcumin in solution. Binding interaction of this complex with calf thymus-DNA (CT-DNA) was investigated using UV/Vis, circular dichroism (CD), FT-IR and cyclic voltammetry. The intrinsic binding constants of CCC with DNA, measured by UV/Vis and cyclic voltammetry, were 1.60 × 10 and 1.13 × 10, respectively. The thermodynamic studies showed that the reaction is enthalpy and entropy favoured. CD analysis revealed that only Λ-CCC interacts with DNA and Δ-CCC form has no tendency towards DNA. Based on FT-IR studies, it was understood that CCC interacts with DNA via minor groove binding. The docking simulation was carried out for finding the binding mode of CCC to DNA, too. All of data demonstrated that the curcumin significantly reduced the affinity of Cr to the DNA and the form of Δ-CCC has no interaction with DNA.
Molecular hybridization and bioisosteric replacement approaches were used to design novel agents with potential use for the treatment of Alzheimer’s disease (AD). Derivatives containing indanone-chalcone core structure bearing ester group were designed and synthesized. In vitro activities of all target compounds against acetylcholinesterase (AChE) were evaluated. The most active compound 8e exhibited anticholinesterase inhibitory activity with IC50 value of 18.7 µM against AChE while the reference drug donepezil (IC50 = 0.0.36 µM on AChE) was used as a control. Also, Aβ1–40 aggregation inhibitory activities of the synthesized compounds were evaluated, and the results showed that compound 8h demonstrates the highest Aβ1–40 aggregation inhibition (81.6%). The results of docking studies revealed that some of compounds fits well into the binding site of AChE. Collectively, this study provide insight for design of small molecules including ester groups to target acetyl choline esterase for further study in the process of design and development of active compounds for AD.
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