Alum as a Catalyst for the Synthesis of Bispyrazole Derivatives

Visible Light-Promoted Green and Sustainable Approach for One-Pot Synthesis of 4,4'-(Arylmethylene)bis(1H-pyrazol-5-ols), In Vitro Anticancer Activity, and Molecular Docking with Covid-19 Mpro

A visible light-promoted, efficient, green, and sustainable strategy has been adopted to unlatch a new pathway toward the synthesis of a library of medicinally important 4,4'-(arylmethylene)bis(1H-pyrazol-5-ols) moieties using substituted aromatic aldehydes and sterically hindered 3-methyl-1-phenyl-2-pyrazoline-5-one in excellent yield. This reaction shows high functional group tolerance and provides a cost-effective and catalyst-free protocol for the quick synthesis of biologically active compounds from readily available substrates. Synthesized compounds were characterized by spectroscopic techniques such as IR, 1HNMR, 13CNMR, and single-crystal XRD analysis. All the synthesized compounds were evaluated for their antiproliferative activities against a panel of five different human cancer cell lines and compared with Tamoxifen using MTT assay. Compound 3m exhibited maximum antiproliferative activity and was found to be more active as compared to Tamoxifen against both the MCF-7 and MDA-MB-231 cell lines with an IC50 of 5.45 and 9.47 μM, respectively. A molecular docking study with respect to COVID-19 main protease (Mpro) (PDB ID: 6LU7) has also been carried out which shows comparatively high binding affinity of compounds 3f and 3g (-8.3 and -8.8 Kcal/mole, respectively) than few reported drugs such as ritonavir, remdesivir, ribacvirin, favipiravir, hydroxychloroquine, chloroquine, and olsaltamivir. Hence, it reveals the possibility of these compounds to be used as effective COVID-19 inhibitors.

Methyl linked pyrazoles: Synthetic and Medicinal Perspective

Pyrazoles, an important and well known class of the azole family, have been found to show a large number of applications in various fields specially of medicinal chemistry. Among pyrazole derivatives, particularly, methyl substituted pyrazoles have been reported as the potent medicinal scaffolds that exhibit a wide spectrum of biological activities. The present review is an attempt to highlight the detailed synthetic approaches for methyl substituted pyrazoles along with in depth analysis of their respective medical significances till March2021. It is hoped that literature sum-up in the form of present review article would certainly be a great tool to assist the medicinal chemists for generating new leads possessing pyrazole nucleus with high efficacy and less microbial resistance.

Potassium Alum [KAl(SO4)2∙12H2O] solid catalyst for effective and selective methoxylation production of alpha-pinene ether products

Methoxylation is a relevant technological process applied in the production of high-value α-pinene derivatives. This report investigates the use of potassium alum [KAl(SO₄)₂ · 12H₂O] as a catalyst in the methoxylation of α-pinene. In this study, the methoxylation reaction was optimized for the highest conversion of α-pinene and selectivity, assessed for the factors, catalyst loading (0.5; 1.0; and 1.5 g), volume ratio of α-pinene: methanol (1:4, 1:7, 1:10), reaction temperature (50, 55, 60 and 65 °C), and reaction time (72, 144, 216, 288, 360 min). The highest selectivity of KAl(SO₄)₂∙12H₂O in the methoxylation of α-pinene was achieved under an optimal condition of 1 g of catalyst loading, volume ratio of 1:10, as well as the reaction temperature and incubation time of 65 °C and 6 h, respectively. GC–MS results revealed the yields of the methoxylated products from the 98.2% conversion of α-pinene, to be 59.6%, 8.9%, and 7.1% for α-terpinyl methyl ether (TME), fenchyl methyl ether (FME), bornyl methyl ether (BME), respectively. It was apparent that a lower KAl(SO₄)₂∙12H₂O loading (0.5–1.5 g) was more economical for the methoxylation reaction. The findings seen here indicated the suitability of the KAl(SO₄)₂ · 12H₂O to catalyze the methoxylation of α-pinene to produce an commercially important ethers.