Study of 1,3-Dipolar Cycloaddition and Ring Contraction of New 1,4-Phenylene-bis[1,5]benzothiazepine Derivatives

Ultrasound-assisted synthesis of novel chalcone, heterochalcone and bis-chalcone derivatives and the evaluation of their antioxidant properties and as acetylcholinesterase inhibitors

The chalcone and bis-chalcone derivatives have been synthesized under sonication conditions via Claisen-Schmidt condensation with KOH in ethanol at room temperature (20-89%). The structures were established on the basis of NMR, IR, Single-crystal XRD, and MS. The best compound 3u had inhibitory activity (IC₅₀ = 7.50 µM). The synthesis, the antioxidative properties, chemical reactivity descriptors supported in Density Functional Theory (DFT), acetylcholinesterase (AChE) inhibition and their potential binding modes, and affinity were predicted by molecular docking of a number of morpholine-chalcones and quinoline-chalcone. A series of bis-chalcones are also reported. Molecular docking and an enzyme kinetic study on compound 3u suggested that it simultaneously binds to the catalytic active site (CAS) and peripheral anionic site (PAS) of AChE. Moreover, the pharmacokinetic profile of these compounds was investigated using a computational method.

A Way to Improve Luminescent Efficiency of Bis-Chalcone Derivatives

Chalcone related compounds have been reported as a poor luminescence molecule due to the quenching processes from the intramolecular torsional motions andcis-transisomerization in theα,β-unsaturated ketone moiety. Despite this limitation, we found a way to improve the luminescent efficiency of our bis-chalcone derivative. In this project, two series of bis-chalcone compounds have been synthesized through Claisen-Schmidt condensation by reacting terephthaldehyde or 2,5-dimethoxyterephthaldehyde with the respective R-acetophenone [where R = H (1aand2a) andortho-hydroxy (1band2b)] in 1 : 2 mole ratio. The presence of a methoxy (OMe) substituent on the central phenyl ring of bis-chalcone has weakened the C=C bond at theα,β-unsaturated ketone moiety of2aand2b. Interestingly, the OMe group has improved the emission efficiency of the bis-chalcone; that is, the quantum yield of1ain DCM solution was not able to be determined due to poor luminescence, but the quantum yield of2ain DCM solution was improved to 0.57. In addition, compound2aalso shows solvatochromism effect where theλmaxemission shifted from 499 nm in nonpolar solvents (benzene) to 523 nm in polar solvents (acetonitrile). This work provides another way to improve the emission efficiency of chalcone related compounds apart from using the complexation method which has been reported before.