Current Organocatalysis - Online First

In this study, three amine-tethered DMAP cation bromide catalysts were prepared using two different mole ratios of 4-dimethylpyridine (DMAP) and 3-bromopropylamine hydrobromide (BPA·HBr) in two different solvents, namely, acetonitrile and ethanol. Then, prepared catalysts were employed for CO2 cycloaddition with styrene and propylene epoxides under metal- and solvent-free conditions.

The impact of mole ratio and solvent selection to prepare the designed product using a simple and cost-effective procedure was demonstrated systematically and was discussed in detail. Moreover, the influence of amine-tethered DMAP cation catalyst structures and reaction conditions on the cycloaddition was investigated, and the CO2 conversion proceeded smoothly at 80°C and 0.2 MPa for the synthesis of cyclic carbonates in good to excellent yields and high selectivity.

The current protocol could be a promising process at an industrial scale due to the high recyclability of the catalyst (10 cycles).

In summary, three catalytic systems bearing amine-tethered DMAP cation have been investigated for the chemical fixation of CO2 into five-membered cyclic carbonates at mild conditions.

The Developed CuO-ZnO nanocomposite has been demonstrated as a new and environmentally friendly catalyst for one-pot multicomponent reaction between aldehydes, 2-naphthol and amides in the synthesis of 1-amidoalkyl-2-naphthols.

The new catalyst was synthesized by a ball-milling method by mixing a mixture of CuO and ZnO powder in various proportions and characterized by different spectroscopic methods such as powder X-ray diffraction (pXRD), Scanning Electron Microscopy (SEM), UV-Visible analysis, EDAX elemental analysis and mapping. The advantages of the devised protocol include a green approach, simple work-up procedures, avoidance of hazardous solvents, and good to excellent yields. RE

Evaluation of the catalyst performance in the synthesis of some 1-amidoalkyl-2-naphthols showed presentable results. Sixteen derivatives were synthesized in desirable yield by our new method (4a-4p). CuO-ZnO nanocomposite as a safe and efficient catalyst could be reused up to 5 runs for the synthesis of naphthol derivatives without any significant decrease in its potency.

The High purity of the products and desirable yields are other points that make the present work more attractive.

Heterocyclic compounds with O, N, and/or S atoms are highly valuable in drug discovery and development. Their pyrazole moieties find applications in various fields, such as herbicides, corrosion inhibitors, electron transport materials, polymers, and luminescent materials. Consequently, there is a pressing need in medicinal chemistry to develop new antibacterial agents to enhance therapeutic efficacy and safety.

A newer biologically active 1-(4-substitutedphenyl)-5-chloro-3-methyl-1Hpyrazole-4-carboxylic acid analogue was synthesized by the para-substituted phenylhydrazine. All the synthesized compounds were characterized by NMR, mass spectral, and IR spectrum examinations, as well as C, H, and N analyses. The synthesized compounds were screened for antibacterial and antifungal activities. Furthermore, a molecular docking study was performed to elucidate the binding modes of synthesized ligands in the active pockets of DNA gyrase and CYP51 (PDB IDs: 4uro and 5tz1, respectively) for exhibiting the binding modes and predicting the mechanism of action of synthesized ligands.

Five compounds (2Rb, 2Re, 2Rg, 2Rh, and 2Ri) demonstrated significant antibacterial action against gram-positive B. subtilis and gram-negative E. coli and antifungal activity against C. albicans and A. niger compared to the standard drugs cefixime and ketoconazole. Furthermore, molecular docking was employed to reveal how the newly synthesized ligands bind within the active pockets. It was found that compound 2Rb demonstrated significant antibacterial activity, and compound 2Rg had good antifungal activity.

The current study highlights the unique structural characteristics and significant biological activity of the synthesized compounds. In the pursuit of novel antibacterial and antifungal molecules, these compounds could prove beneficial to society.