FeCl3 /PVP as Green Homogeneous Catalyst to Synthesize 5-Amino-1H -Pyrazole-4-Carbonitriles from Malononitrile Derivatives

Exploration of anti-inflammatory activity of pyrazolo[3,4-d]pyrimidine/1,2,4-oxadiazole hybrids as COX-2, 5-LOX and NO release inhibitors: Design, synthesis, in silico and in vivo studies

New pyrazolo[3,4-d]pyrimidine derivatives 7a-h and 8a-h were synthesized and evaluated for their in vitro inhibitory potential against COX-1, COX-2, 5-LOX along with the NO release inhibitory activity to assess their anti-inflammatory potential. Most compounds confered inhibitory activity at a micromolar level and exhibited prominent selectivity towards COX-2 especially in the 8a-h series. The most useful compound 8e as a COX-2/5-LOX dual inhibitor, exhibited IC50 results of; 1.837 µM for COX-2, 2.662 µM for 5-LOX with an acceptable NO release inhibition rate of 66.02 %. Compounds 7e, 7f, 8e and 8f proved their efficiency as 5-LOX/NO release dual inhibitors; with IC50 values of 2.833, 1.952, 2.662 and 1.573 µM, respectively for 5-LOX biotarget, and with superior NO inhibitory ratio of 73.85, 65.57, 66.02 and 72.28 %, respectively. The in vivo anti-inflammatory assay explored that 7e is the most effective with minimal gastric ulceration prevalence. Molecular docking in the active site of both COX-2 and 5-LOX showed that, the most active 8e and 7e are correctly oriented inside the COX-2 binding pocket with unique binding mode independently on the reference celecoxib. Also, they demonstrated superior binding affinities to the 5-LOX enzyme over both the Zileuton as a reference drug and the normal ligand 30Z. The stability of the complex formed between the most promising candidates 7e or 8e with the COX-2 and 5-LOX active sites, was considered using a typical atomistic 100 ns dynamic simulation study. Investigation of the SAR revealed the importance of both the sulfonamide group in the 8a-h series and the substituents of the 3-phenyl ring tethered on the 1,2,4-oxadiazole core.

Recent Advances in Synthesis and Properties of Pyrazoles

Pyrazole-containing compounds represent one of the most influential families of N-heterocycles due to their proven applicability and versatility as synthetic intermediates in preparing relevant chemicals in biological, physical-chemical, material science, and industrial fields. Therefore, synthesizing structurally diverse pyrazole derivatives is highly desirable, and various researchers continue to focus on preparing this functional scaffold and finding new and improved applications; this review highlights some of the most recent and strategic examples regarding the synthesis and properties of different pyrazole derivatives, mainly reported from 2017–present. The discussion involves strategically functionalized rings (i.e., amines, carbaldehydes, halides, etc.) and their use in forming various fused systems, predominantly bicyclic cores with 5:6 fusion taking advantage of our experience in this field and the more recent investigations of our research group.