Synthesis, Cytotoxicity, Antimicrobial and Docking Simulation of Novel Pyrazolo[3,4-d]pyrimidine and pyrazolo[4,3-e][1,2,4]triazolo[3,4-c] pyrimidine Derivatives

The Synthesis, Antimicrobial Activity, and Molecular Docking of New 1, 2, 4-Triazole, 1, 2, 4-Triazepine, Quinoline, and Pyrimidine Scaffolds Condensed to Naturally Occurring Furochromones

This study aims to synthesize a new series of furochromone derivatives, evaluate their antimicrobial properties, and improve the permeability of potent compounds to inhibit different types of bacteria and fungi. Hence, Substituted furo[3,2-g]chromene-6-carbonitrile (3a,b) readily form 7-amino-5-methyl-furo [3,2-g]chromene-6-carbonitrile (4a,b) via reduction using sodium borohydride in methanol. The same compounds of (4a,b) were used as starting materials for the synthesis of new furochromone derivatives such as furochromeno [2,3-d]pyrimidines, N- (6-cyano- 5-methyl-furochromene) acetamide, N-(6-cyano-5-methyl-furo chromene)-2-phenyl acetamide, N- (6-cyano-5-methyl-furochromene) formimidate, furochromeno[1,2,4]triazepin-5-amine, furochrom ene-6-carboxamide, furochromeno[1,2,4]triazolopyrimidines, and furochromeno[2,3-b]quinolin- 6-amine. The structures of the new compounds were determined using spectroscopy: Nuclear Magnetic Resonance (¹H, ¹³C), Mass spectra, Infrared, and elemental analysis. Molecular docking studies were conducted to investigate the binding patterns of the prepared compounds against DNA-gyrase (PDB 1HNJ). The results displayed that compounds furochromenotriazolopyrimidine (20a,b), furochromenoquinolin-6-amine (21a,b), furochromenotriazepin-amine (9a,b), and furo- chromenopyrimidine-amine (19a,b) were excellent antimicrobials.

Hydrazonoyl bromide precursors as DHFR inhibitors for the synthesis of bis-thiazolyl pyrazole derivatives; antimicrobial activities, antibiofilm, and drug combination studies against MRSA

Microbial resistance is a big concern worldwide, making the development of new antimicrobial drugs difficult. The thiazole and pyrazole rings are important heterocyclic compounds utilized to produce a variety of antimicrobial medications. As a result, a series of new bis-thiazolyl-pyrazole derivatives 3, 4a-c, 5a, b, and 6a-c was synthesized by reacting bis hydrazonoyl bromide with several active methylene reagents in a one-pot reaction. The assigned structure was characterized entirely based on elemental and spectral analyses. The antimicrobial activity represented by MIC was performed using a resazurin-based turbidimetric (TB) assay. The results exhibited good antimicrobial activity against gram-positive strains, especially S. aureus (ATCC6538) while showing poor to moderate activity against gram-negative and fungal strains. Furthermore, the most active derivatives 3, 4a, 4c, and 5b were evaluated for MIC, MBC, antibiofilm, hemolytic assay, and drug combination testing against two S. aureus (ATCC6538) and MRSA (ACL18) strains. Additionally, bis-thiazolyl pyrazole 3, 4c, and 5b exhibited more potent inhibitory activity for DHFR with IC₅₀ values (6.34 ± 0.26, 7.49 ± 0.28, and 3.81 ± 0.16 µM), respectively, compared with Trimethoprim (8.34 ± 0.11 µM). The bis-1-(substituted-thiazol-2-yl)-1H-pyrazole-4-carbonitrile derivative 5b was the most active member with MIC values ranging from (0.12-0.25 µM) compared to Vancomycin (1-2 µM), and MBC values ranging from (0.5-1 µM) for S. aureus (ATCC6538) and MRSA (ACL18). Surprisingly, compound 5b displayed bactericidal behavior, synergistic effect with three commercial antibiotics, and inhibited DHFR with 2.1 folds higher than Trimethoprim. Finally, good findings were obtained from in silico investigations incorporating toxicity prediction and molecular docking simulation.

4-(3-Phenyl-1H-pyrazolo[3,4-d]pyrimidin-1-yl)thieno[3,2-d]pyrimidine

A new hybrid compound, 4-(3-phenyl-1H-pyrazolo[3,4-d]pyrimidin-1-yl)thieno[3,2-d]pyrimidine 3, with promising biological activity was efficiently synthesized by the reaction of 3-phenyl-1-(thieno[3,2-d]pyrimidin-4-yl)-1H-pyrazol-5-amine with Vilsmeier–Haack reagent and subsequent treatment with ammonium carbonate. The structure of the synthesized compound was fully characterized by 1H-, 13C-NMR, IR spectroscopy, mass-spectrometry and elemental analysis.