Synthesis of New Pyrazolo[3,4-d]pyrimidine Derivatives: NMR Spectroscopic Characterization, X-Ray, Hirshfeld Surface Analysis, DFT, Molecular Docking, and Antiproliferative Activity Investigations

Four new pyrazolo[3,4-d]pyrimidines (P1-P4) were successfully synthesized in good relative yields by reacting 3-methyl-1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4-ol with various alkylating agents (methyl iodide, propargyl bromide, and phenacyl bromide) at room temperature in DMF solvent, employing liquid-solid phase transfer catalysis. The P1-P4 structures were elucidated using NMR spectroscopy and X-ray diffraction. Intermolecular interactions in P1-P4 were analyzed via Hirshfeld surface analysis and 2D fingerprint plots. Geometrical parameters were accurately modeled by DFT calculations using the B3LYP hybrid functional combined with a 6-311++G(d,p) basis set. The antiproliferative activity of P1-P4 towards colorectal carcinoma (HCT 116), human hepatocellular carcinoma (HepG2), and human breast cancer (MCF-7) cell lines, along with one normal cell line (WI38) was investigated using the MTT assay and sunitinib as a reference. Compounds P1 and P2 exhibited antiproliferative activities comparable to the reference drug towards all tested cells, with an IC50 range of 22.7-40.75 µM. Both compounds also showed high selectivity indices and minimal cytotoxic effects on the normal cell line. Molecular docking revealed that the significant antiproliferative activity may attributed to the number and type of intermolecular hydrogen bonding established between pyrazolo[3,4-d]pyrimidines and DNA topoisomerase, a common target for various anticancer agents.

Recent developments on microwave-assisted organic synthesis of nitrogen- and oxygen-containing preferred heterocyclic scaffolds

In recent decades, the utilization of microwave energy has experienced an extraordinary surge, leading to the introduction of innovative and revolutionary applications across various fields of chemistry such as medicinal chemistry, materials science, organic synthesis and heterocyclic chemistry. Herein, we provide a comprehensive literature review on the microwave-assisted organic synthesis of selected heterocycles. We highlight the use of microwave irradiation as an effective method for constructing a diverse range of molecules with high yield and selectivity. We also emphasize the impact of microwave irradiation on the efficient synthesis of N- and O-containing heterocycles that possess bioactive properties, such as anti-cancer, anti-proliferative, and anti-tumor activities. Specific attention is given to the efficient synthesis of pyrazolopyrimidines-, coumarin-, quinoline-, and isatin-based scaffolds, which have been extensively studied for their potential in drug discovery. The article provides valuable insights into the recent synthetic protocols and trends for the development of new drugs using heterocyclic molecules.

Insights into the medicinal chemistry of heterocycles integrated with a pyrazolo[1,5-a]pyrimidine scaffold

Pyrazolo[1,5-a]pyrimidines are the dominant motif of many drugs; for instance, zaleplon and indiplon are sedative agents and ocinaplon was identified as an anxiolytic agent. The importance of this class of compounds lies in its varied and significant biological activities, and accordingly, considerable methods have been devised to prepare these compounds. Hence, other derivatives of this class of compounds were prepared by substitution reactions with different nucleophiles exploiting the activity of groups linked to the ring carbon and nitrogen atoms. The methods used vary through the condensation reactions of the aminopyrazoles with 1,2-allenic, enaminonitriles, enaminones, 1,3-diketones, unsaturated nitriles, or unsaturated ketones. Alternatively, these compounds are prepared through the reactions of acyclic reagents, as these methods were recently developed efficiently with high yields. The current review highlighted the recent progress of the therapeutic potential of pyrazolo[1,5-a]pyrimidines as antimicrobial, anticancer, antianxiety, anti-proliferative, analgesic, and antioxidant agents, carboxylesterase, translocator protein and PDE10A inhibitors, and selective kinase inhibitors.

Microwave-assisted decarboxylative reactions: advanced strategies for sustainable organic synthesis

Recent advances in the microwave-assisted decarboxylative reactions of carboxylic acids and their derivatives, including transition-metal-catalyzed and metal-free approaches, are summarized.

Bio-based triacetic acid lactone in the synthesis of azaheterocyclesviaa ring-opening transformation

In the present article a new way of converting biobased triacetic acid lactone (TAL) into azaheterocyclic compounds, such as 4-pyridones, pyrazoles, isoxazolines and isoxazoles, has been found through reactive and multifunctional polycarbonyl intermediates.