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Pyrazolo[1,5-a]pyrimidine (PP) derivatives are an enormous family of N-heterocyclic compounds that possess a high impact in medicinal chemistry and have attracted a great deal of attention in material science recently due to their significant photophysical properties. Consequently, various researchers have developed different synthesis pathways for the preparation and post-functionalization of this functional scaffold. These transformations improve the structural diversity and allow a synergic effect between new synthetic routes and the possible applications of these compounds. This contribution focuses on an overview of the current advances (2015–2021) in the synthesis and functionalization of diverse pyrazolo[1,5-a]pyrimidines. Moreover, the discussion highlights their anticancer potential and enzymatic inhibitory activity, which hopefully could lead to new rational and efficient designs of drugs bearing the pyrazolo[1,5-a]pyrimidine core.

Pyrazolopyridines and pyrazolopyrimidines are 5:6 aza-fused N-heteroaromatic compounds (NHACs) comprising a pyrazole ring fused to a pyridine or pyrimidine ring. They exhibit dipolar behavior due to their π-excessive and π-deficient characteristics conferred by their five- and six-membered rings. These features favor their stability, reactivity, and structural diversity, offering numerous modular and functional derivatives (e.g., pyrazolo[1,2-a]pyridines, pyrazolo[1,5-a]pyrimidines, etc.). They have been utilized to obtain relevant chemicals in pharmaceuticals, photophysics, industry, and materials science; thus, their synthesis is highly desirable for discovering novel or improved applications. Therefore, this review focuses on recent advances in the synthesis and applications of these compounds, considering reports from the last decade (2015–2024), with particular emphasis on photophysics, as they contain dipolar 5:6 aza-fused rings as essential scaffolds for this purpose.

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.

Two pyrene derivatives, substituted at position 1 with isoxazole or NH-pyrazole, were synthesized in 85–87% yield starting from 1-acetylpyrene and via the cyclocondensation reaction of a β-enaminone intermediate with hydroxylamine or hydrazine. The photophysics of the two 5-(1-pyrenyl)-1,2-azoles were explored, revealing that only the isoxazole derivative exhibits good emission properties (ϕF ≥ 74%) but without solvatofluorochromism behavior. However, both probes exhibited noticeable photophysics in the aggregated state (in the presence of H2O and/or in the solid state) and through acid–base interactions (using TFA and TBACN), leveraging the basic and acidic character of the analyzed 1,2-azoles, which was also investigated by 1H NMR spectroscopy. Therefore, the selective incorporation of N-heteroaromatic units into the pyrene scaffold effectively modulates the photophysics and environmental sensitivity of the corresponding probes.

A pseudo-three-component synthesis of N-aroylmethylimidazoles 3 with three new C–N bonds formed regioselectively under microwave conditions was developed. Products were obtained by reacting two equivalents of aroylmethyl bromide (ArCOCH2Br, 1) with the appropriate amidine salt (RCN2H3.HX, 2) and with K2CO3 as a base in acetonitrile. The bicomponent reaction also occurred, giving the expected 4(5)-aryl-1H-imidazoles 4. Notably, the ratio of products 3 and 4 is governed by steric factors of the amidine 2 (i.e., R = H, CH3, Ph). Therefore, a computational study was carried out to understand the reaction course regarding product ratio (3/4), regioselectivity, and the steric effects of the amidine substituent group.

We describe the synthesis of 2-oxo-2H-chromen-7-yl 4-chlorobenzoate 3 in 88% yield by the O-acylation reaction of 7-hydroxy-2H-chromen-2-one 1 with 4-chlorobenzoyl chloride 2 in dichloromethane using a slight excess of triethylamine at 20 °C for 1 h. The ester 3 was completely characterized by mass spectrometry, IR, UV–Vis, 1D, and 2D NMR spectroscopy.

The 1,2,3-Triazole derivatives containing the sulfonyl group have proved their biological importance in medicinal chemistry and drug design. In this sense, we describe the regioselective synthesis of 2-(phenylsulfonyl)-2H-1,2,3-triazole 3 in good yield through a classical sulfonamidation reaction of 1H-1,2,3-triazole 1 with benzenesulfonyl chloride 2 in dichloromethane using a slight excess of triethylamine at 20 °C for 3 h. This procedure is distinguished by its short reaction time, high yield, excellent regioselectivity, clean reaction profile, and operational simplicity. The sulfonamide 3 was characterized by high-resolution mass spectrometry, FT–IR, UV–Vis, 1D and 2D NMR spectroscopy, and elemental analysis. The sulfonamide 3 exhibited moderate activity against UO-31 renal, SNB-75 central nervous system, HCT-116 colon, and BT-549 breast cancer cell lines, with growth inhibition percentages (GI%) ranging from 10.83% to 17.64%.

Pyrazolo[1,5-a]pyrimidine (PP) derivatives are an enormous family of N-heterocyclic compounds that possess a high impact in medicinal chemistry and have attracted a great deal of attention in material science recently due to their significant photophysical properties. Consequently, various researchers have developed different synthesis pathways for the preparation and post-functionalization of this functional scaffold. These transformations improve the structural diversity and allow a synergic effect between new synthetic routes and the possible applications of these compounds. This contribution focuses on an overview of the current advances (2015-2021) in the synthesis and functionalization of diverse pyrazolo[1,5-a]pyrimidines. Moreover, the discussion highlights their anticancer potential and enzymatic inhibitory activity, which hopefully could lead to new rational and efficient designs of drugs bearing the pyrazolo[1,5-a]pyrimidine core.Pyrazolo[1,5-a]pyrimidine (PP) derivatives are an enormous family of N-heterocyclic compounds that possess a high impact in medicinal chemistry and have attracted a great deal of attention in material science recently due to their significant photophysical properties. Consequently, various researchers have developed different synthesis pathways for the preparation and post-functionalization of this functional scaffold. These transformations improve the structural diversity and allow a synergic effect between new synthetic routes and the possible applications of these compounds. This contribution focuses on an overview of the current advances (2015-2021) in the synthesis and functionalization of diverse pyrazolo[1,5-a]pyrimidines. Moreover, the discussion highlights their anticancer potential and enzymatic inhibitory activity, which hopefully could lead to new rational and efficient designs of drugs bearing the pyrazolo[1,5-a]pyrimidine core.

Structures containing 8-hydroxyquinoline scaffold are useful for anticancer drug development. The title ester (5-chloroquinolin-8-yl)-2-fluorobenzoate was prepared by the reaction of 2-fluorobenzoyl chloride with 5-chloro-8-hydroxyquinoline. The structure of the title compound was assigned by diverse spectroscopic techniques. Moreover, a crystallographic study was undertaken and its supramolecular characteristics were analyzed. Thus, the central ester fragment C8/O1/C10(O2)/C11 is almost planar with a root mean square (r.m.s.) deviation of 0.0612 Å and it makes dihedral angles of 76.35(6)° and 12.89(11)°, with quinoline and phenyl rings respectively. The structure shows C–H...X (X = halogen) non-classical hydrogen bonds. It also has a halogen…halogen distance less than the sum of the van der Waals radii (3.2171(15) Å). As a result of interactions with halogen atoms, chains of centrosymmetric dimer that form edge-fused R22(18) rings run parallel to the plane (100).

The examination and choice of an alternate composite material for the high-voltage circuit of Otto cycle internal combustion engines—more commonly known as gasoline engines—are presented in the research that follows. To do this, multicriteria selection procedures are employed, and the outcomes are validated through the use of thermal character simulation software and standard laboratory tests. Nylon is the recommended material for Coils on Plug (COP) high-voltage insulators. Four of the six multicriteria selection techniques utilized in this study were found to be effective. It was discovered through the virtual simulation process that, even in the same environment with the same edge circumstances, the thermal behavior of the materials differs dramatically because the quadrants exhibit different behavior depending on the material. Given that nylon has a lower elasticity modulus than silicone, it was determined that the dimensions are crucial for the nylon Spark Plug Boot (SPB) to comply with the dielectric isolation process. It must have a minimal clearance in order to be related to the geometry of the spark plug and perform the perfect insulation in this manner.