From imidates to vinyl-1,2,4-triazoles: Synthesis, mechanistic aspects and first issues of their reactivity

Synthesis methods of 1,2,3-/1,2,4-triazoles: A review

Triazole, comprising three nitrogen atoms and two carbon atoms, is divided into two isomers 1,2,3-triazole and 1,2,4-triazole. Compounds containing a triazole are one of the significant heterocycles that exhibit broad biological activities, such as antimicrobial, analgesic, anti-inflammatory, anticonvulsant, antineoplastic, antimalarial, antiviral, antiproliferative, and anticancer activities. A great quantity of drugs with a triazole structure has been developed and proved, for example, ketoconazole and fluconazole. Given the importance of the triazole scaffold, its synthesis has attracted much attention. This review summarizes the synthetic methods of triazole compounds from various nitrogen sources in the past 20 years.

Development of Potent 3-Br-isoxazoline-Based Antimalarial and Antileishmanial Compounds

Starting from the structure of previously reported 3-Br-isoxazoline-based covalent inhibitors of P. falciparum glyceraldehyde 3-phosphate dehydrogenase, and with the intent to improve their metabolic stability and antimalarial activity, we designed and synthesized a series of simplified analogues that are characterized by the insertion of the oxadiazole ring as a bioisosteric replacement for the metabolically labile ester/amide function. We then further replaced the oxadiazole ring with a series of five-membered heterocycles and finally combined the most promising structural features. All the new derivatives were tested in vitro for antimalarial as well as antileishmanial activity. We identified two very promising new lead compounds, endowed with submicromolar antileishmanial activity and nanomolar antiplasmodial activity, respectively, and a very high selectivity index with respect to mammalian cells.

DFT investigation of solvent, substituent, and catalysis effects on the intramolecular Diels-Alder reaction

In this study, we report on a DFT investigation of two intramolecular Diels-Alder furan reactions. Optimizations of the studied structures, TS and IRC calculations, were carried out at B3LYP/6-31G(d) level. We have studied the effect of substituent, solvent and Lewis acid catalyst on cyclization-retrocyclization equilibria, activation energies, and stability of the desired products. The analysis of orbital coefficients, IRC curves, and Wiberg indices have proved that both reactions are under orbital control. We have found that for the reaction I (2↔4 + 5), where R = H, the exo attack is favored by hydrogen bond interaction, while for R = t-Bu, the steric hindrance leads to the endo attack. For the reaction II (3 → 6 + 7), the t-Bu-substituted products are the most stable ones. At another level, we have found that it is recommended to use polar organic solvents as DMSO with Lewis acid catalyst BF₃. The latest leads to accelerate the reaction II with stabilization of the desired products.

One-pot parallel synthesis of 1,3,5-trisubstituted 1,2,4-triazoles

An implementation of the three-component one-pot approach to unsymmetrical 1,3,5-trisubstituted-1,2,4-triazoles into combinatorial chemistry is described. The procedure is based on the coupling of amidines with carboxylic acids and subsequent cyclization with hydrazines. After the preliminary assessment of the reagent scope, the method had 81% success rate in parallel synthesis. It was shown that over a billion-sized chemical space of readily accessible ("REAL") compounds may be generated based on the proposed methodology. Analysis of physicochemical parameters shows that the library contains significant fractions of both drug-like and "beyond-rule-of-five" members. More than 10 million of accessible compounds meet the strictest lead-likeness criteria. Additionally, 195 Mln of sp³-enriched compounds can be produced. This makes the proposed approach a valuable tool in medicinal chemistry.

Design and synthesis of coumarin-triazole hybrids: biocompatible anti-diabetic agents, in silico molecular docking and ADME screening

The current study demonstrates the synthesis of coumarin-triazole hybrids 8 (a-e) in four steps starting from substituted salicylaldehyde 1 (a-e), and diethyl malonate 2. The spectroscopic studies provide the structure proofs of the new compounds, and the molecular structure of an intermediate 3a by crystallographic studies. The crystal structure analysis revealed the C–H...O, C–H... π, C–O...π and π...π molecular interactions. Further, the intermolecular interactions were quantified using Hirshfeld surface analysis and the DFT method B3LYP functional with 6–311++ G (d,p) basis set was employed to optimize the molecular geometry. The synthesized new coumarin-triazole hybrids, 8 (a–e) were screened for their α-amylase inhibitory potentials, and the results suggest that amongst the series, compounds 8c, and 8e show the promising inhibition of the enzyme, and might act as lead molecules for anti-diabetic activities. To understand the mode of action in silico molecular docking and ADME screening were performed.