Letters in Organic Chemistry - Volume 20, Issue 1, 2023

Although amides are one of the most abundant bonds in biology and medicinal chemistry, methods to prepare them are still limited. To expand on current methods for the formation of amides bonds, organocatalysts (thiourea-based) were developed to mediate the conversion of esters to amides. The reactions proceed in good to moderate yields and tolerate a variety of functional groups. ¹H NMR titration and computational studies show a strong hydrogen-bonding interaction between the thiourea catalyst and the ester moiety. This hydrogen-bonding interaction is proposed to be the driving force for the amidation of esters.

Recent findings confirm that thiosemicarbazones and thiazoles offer a wide range of biological properties. We report here the synthesis of two series of highly functionalized thiazole-derived compounds from the reactions of various indole-derived thiosemicarbazones with diethyl acetylenedicarboxylate and 4-bromophenacyl bromide. As a result, a series of new derivatives of thiosemicarbazone, thiazolidinone, and thiazole bearing an indole moiety was synthesized and developed in good yields.

Nanoparticles have been proven to be efficient catalysts for a variety of chemical reactions, with added advantages such as the reuse of catalysts, increasing the scale of reactions employing continuous flow techniques, and simple separation of the reaction milieu, making them green, efficient, and lucrative choices. Over the last decade, gold nanoparticles (AuNPs) have appeared as promising and efficient catalysts in the field of sustainable organic synthesis. On the other hand, heterocycles are significant scaffolds in a variety of natural products and other biologically active molecules, as well as useful compounds for organic and material chemistry. Therefore, the progress of proficient techniques for the synthesis of heterocyclic compounds is always of major significance. This mini-review focuses on some of the most important AuNPs catalyzed heterocyclic compound synthesis processes. Wherever essential, the exclusivity of the approaches has been discussed by emphasizing substrate diversity, selectivity, product yields, and mechanistic features.

5H-Chromeno[2,3-b]pyridine derivatives are a series of the most important compounds of chromenes with industrial, biological, and medicinal properties. These compounds are known as the privileged medicinal scaffold and can be synthesized by different methods such as multicomponent reactions (MCRs), Multicomponent coupling reactions (MCCRs), pot, atom, and step economy (PASE). In this review article, we have focused on the significant reactions for the syntheses and applications of 5H-chromeno[2,3-b] pyridines, including two-component reactions, three-component reactions, fourcomponent reactions, and multi-step reactions. This review is expected to serve as a useful conceptual overview and inspire the next generation to develop the different strategies for the preparation of 5HChromeno[ 2,3-b] pyridine derivatives.

In this work, we used a highly efficient and easy approach for synthesizing imidazolecarboxylate salt through the reaction between α-amidino carboxylic acids and α-halo ketones with as readily available starting materials in the presence of KHCO3 at THF under reflux. Targeted synthesis of this type of imidazole bearing the carboxylic acid group in a single structure, in addition to the biological properties enriched as a ligand, is very popular in the manufacture of catalysts. The salient features of this protocol include eco-friendly, high atom-economical, easy and mild conditions that led to the production of all products with high yields. Furthermore, all products were purified without the need for column chromatography through the GAP chemistry (group-assisted purification chemistry) technique.

Background: Cichorium intybus is a perennial herb in the Asteraceae family that has significant ethano-medical properties and is utilized in Ayurveda and Unani therapy. The enzyme costunolide synthase contributes to the biosynthesis pathway of sesquiterpene lactones, which is thought to provide the plant with antimalarial action. Methods: This work uses several in-silico techniques along with docking experiments to show the structural and physiochemical characteristics of the enzyme costunolide synthase. Costunolide synthase protein interacts with lactucin and lactucopicrin with lower energy interactions of -4.99 kcal/mol for total 3 hydrogen bonds and -6.55 kcal/mol for total 2 hydrogen bonds, respectively. One domain named CYP 450 has been found, which catalyzes a variety of oxidative reactions of a large number of structurally different compounds that are both endogenous and exogenous from all major domains of life. The mitochondrial cellular localization of protein was revealed with a maximum score of 1.833. Results: The phylogenetic study revealed that the enzyme costunolide synthase from Cichorium intybus has a greater resemblance to Cichorium endivia and Lactuca sativa of costunolide synthase. Molecular docking findings of sesquiterpene lactones (lactucin and lactucopicrin) with Plasmepsin II protein of P. falciparum parasites after clinical trials with sesquiterpene lactones may give more evidence and explanation for the active involvement of lactucin and lactucopicrin as an antimalarial compound. Conclusion: This research will be used in future wet-lab studies to figure out how the costunolide synthase enzyme regulates sesquiterpene lactones and to investigate additional regulatory enzyme involved in the synthesis of sesquiterpene lactones.

A bromination of hydrocarbons with CBr4 as a bromine source, promoted by NaOH, has been developed. The reaction method with high efficiency and regioselectivity for the synthesis of C3-brominated imidazo[1,2-α]pyridines. An effective and simple method of C-X bond construction has been developed, which is a supplement to the halide of imidazo[1,2-α]pyridines.

The SARS-CoV-2 pandemic has led to major worldwide health concerns. Design and detection of effective drugs and adjuvant therapies to treat COVID-19 disease in the shortest possible time have become one of the most critical global challenges. In this study, we investigated the effect of some anticancer drugs against the COVID-19 main protease (M^pro/3CL^pro) to detect an effective treatment, using a molecular docking approach as a fast and cost-effective method. Accordingly, 44 anticancer drugs were selected as a target for the virtual screening. The molecular docking study was carried out using AutoDock Tools (ADT), AutoDock Vina, Discovery Studio, and Open Babel software. Tucatinib, selinexor, irinotecan, olaparib, dacomitinib, lapatinib, ibrutinib, and pazopanib were ranked top as COVID-19 inhibitors with the respective binding energy of -10.1, -9.4, -9.2, -8.9, -8.7, -8.7, -8.6, and -8.5 kcal/mol. Among the drugs tested, tucatinib displayed the highest binding affinity and strong interactions with the active site of COVID-19 3CL^pro (-10.1 kcal/mol). Pharmacokinetics properties and drug-likeness of the top 8 selected anticancer drugs were evaluated. The results showed that these drugs could be utilized as potential inhibitors against the main protease of COVID-19, which can help control the spread of this disease. However, in vitro, in vivo studies, and clinical trials will help evaluate the efficacy of these drugs against COVID-19.

Specific recognition of ultra-trace levels of ions in semi-water using super-quicker methods is still a challenge for environmental monitoring. The development of ion-selective fluorescence sensors for selective detection of Al3+ is an essential task because of the importance of Al3+ to the human body. A fluorescent chemosensor S based on quinoline as a binding and signaling unit has been designed and synthesized in a one-step procedure. More importantly, when Al3+ ions are added to the sensor S, it showed immediate responses toward Al3+ ions in dimethylformamide (DMF) solution with the strong blue fluorescence quenching. And the S detection limit (LOD) of Al3+ in aqueous media (1.0 M) is 1.75x10-7 M. Furthermore, the proposed mechanism of action for sensor S and metal ions has been learned using some research techniques such as FE-SEM, FT-IR, XRD and XPS. Further, the fluorescence chemical sensor specifically recognizes the metal aluminum ion.