Synthesis of Functionalized Thiophene Based Pyrazole Amides via Various Catalytic Approaches: Structural Features through Computational Applications and Nonlinear Optical Properties

Abstract

In the present study, pyrazole-thiophene-based amide derivatives were synthesized by different methodologies. Here, 5-Bromothiophene carboxylic acid (2) was reacted with substituted, unsubstituted, and protected pyrazole to synthesize the amide. It was observed that unsubstituted amide (5-bromo-N-(5-methyl-1H-pyrazol-3-yl)thiophene-2-carboxamide (7) was obtained at a good yield of about 68 percent. The unsubstituted amide (7) was arylated through Pd (0)-catalyzed Suzuki–Miyaura cross-coupling, in the presence of tripotassium phosphate (K3PO4) as a base, and with 1,4-dioxane as a solvent. Moderate to good yields (66–81%) of newly synthesized derivatives were obtained. The geometry of the synthesized compounds (9a–9h) and other physical properties, like non-linear optical (NLO) properties, nuclear magnetic resonance (NMR), and other chemical reactivity descriptors, including the chemical hardness, electronic chemical potential, ionization potential, electron affinity, and electrophilicity index have also been calculated for the synthesized compounds. In this study, DFT calculations have been used to investigate the electronic structure of the synthesized compounds and to compute their NMR data. It was also observed that the computed NMR data manifested significant agreement with the experimental NMR results. Furthermore, compound (9f) exhibits a better non-linear optical response compared to all other compounds in the series. Based on frontier molecular orbital (FMO) analysis and the reactivity descriptors, compounds (9c) and (9h) were predicted to be the most chemically reactive, while (9d) was estimated to be the most stable among the examined series of compounds.

Synthesis of Functionalized N-(4-Bromophenyl)furan-2-carboxamides via Suzuki-Miyaura Cross-Coupling: Anti-Bacterial Activities against Clinically Isolated Drug Resistant A. baumannii, K. pneumoniae, E. cloacae and MRSA and Its Validation via a Computational Approach

“…The required product was then purified by using flash column chromatography with ethyl acetate and n-hexane (20:80). NMR spectroscopy and mass spectroscopy analysis was used to characterize the desired product [ 30 ].…”

1H-Pyrazolo[3,4-b]quinolines: Synthesis and Properties over 100 Years of Research

“…Especially in conjunction with various electron acceptors (e.g., electron-deficient aromatics and heteroaromatics), pyrazole derivatives emerge as highly efficient, tunable light emitters [148][149][150]. Such structural motifs, including pyrazoloquinolines, have been intensively studied in the area of advanced dye chemistry, and most recently as electroluminescent materials [6,151,152], fluorescence sensors [153,154] and second-order nonlinear optical materials [155][156][157].…”

Facile Synthesis of Functionalized Phenoxy Quinolines: Antibacterial Activities against ESBL Producing Escherichia coli and MRSA, Docking Studies, and Structural Features Determination through Computational Approach

“…The molecules 3a-3h were examined for antibacterial activity at five different deliberations (10,20,30,40, and 50 mg/well) against ESBL producing E. coli and MRSA by agar well diffusion method. The broth dilution method was practiced documenting the MIC and MBC values.…”

“…From the value of E HOMO , we can predict the nucleophilic nature and by the value of E LUMO, the electrophilic nature of the compound can be imagined [29]. The HOMO energy (E HOMO ), LUMO energy (E LUMO ), and HOMO-LUMO energy gap (E LUMO -E HOMO ) are the substantial aspects for the prediction of general reactivity of the molecule [30], chemical softness, rigidity, constancy, and physical appearance of the elements and compounds under study. Materials with more HOMO-LUMO energy difference (E gap ) are known as rigid and stiff molecules with elevated kinetic strength and less chemical reactivity [31].…”

“…prediction of general reactivity of the molecule [30], chemical softness, rigidity, constancy, and physical appearance of the elements and compounds under study. Materials with more HOMO-LUMO energy difference (Egap) are known as rigid and stiff molecules with elevated kinetic strength and less chemical reactivity [31].…”