Journal of Chemical Sciences最新文献

Novel (E)-3-(dimethylamino)-1-(quinolin-3-yl)prop-2-en-1-one and (E)-3-(dimethylamino)-1-(quinolin-3-yl)but-2-en-1-one (2) were synthesized in excellent yields by reacting 3-acetylquinoline with DMF-DMA and DMA-DMA respectively. Subsequently, 2 were used as the precursors for the synthesis of 3-(pyrazolo[1,5-a]pyrimidin-7-yl)quinolines and 3-(5-methylpyrazolo[1,5-a]pyrimidin-7-yl)quinolines (4). All the synthesized compounds were subjected to structure elucidation and evaluated for their antiparasitic potential with special reference to their anti-malarial properties. The in-vitro studies of the synthesized compounds revealed moderate anti-malarial efficacy for compounds 4b, 4c, 4d, 4k, 4l and 4m. Compounds 4g and 4i showed highest activity displaying IC₅₀ values of 2.10 and 2.77 (mu)M, respectively, for the chloroquine-sensitive strain of P. falciparum, and 4.26 and 2.87 (mu)M, respectively, for the chloroquine-resistant strain. The in-vitro cytotoxicity of the compounds showed CC₅₀ as >500 µM and thus, found to be safe. Molecular docking of the novel series of ligand 4a–4n against the target protein P. falciparum PfLDH enzyme target (PDB ID 1LDG) revealed good binding energies ranging from –8.06 to –11.02 kcal/mol with low inhibition constants summed up as 1.04, 473.55, 352.51, 290.9, 437.86, 1.23, 41.18, 26.81, 162.76, 300.38, 70.2, 29.84, 4.14, 8.4 µM, respectively. The lower the inhibition constant (µM), the greater is the binding affinity and lower the medication required to inhibit the activity of the target receptor.

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(E)-3-(dimethylamino)-1-(quinolin-3-yl)but-2-en-1-one with 3-aminopyrazole under ultrasonic irradiation in aqueous medium yielded novel 3-(pyrazolo[1,5-a]pyrimidin-7-yl)quinolines and 3-(5-methylpyrazolo[1,5-a]pyrimidin-7-yl)quinolines. Antimalarial studies against Pf3D7 strain resulted in moderate activity with compound 4g showing highest activity. Molecular docking analysis of the compounds reveals the potentiality of the series to serve as antimalarial agents against CQ-sensitive (Pf3D7) and multi-drug-resistant (PfK1).

Readily available, naturally derived lignin was transformed into a Brønsted acidic organocatalyst. The obtained catalyst was utilized in the environmentally benign synthesis of biologically relevant indole derivatives such as vibrindole, turbomycin, etc. The scope of the developed methodology was further extended for the synthesis of aniline-tethered indoles, 4H-chromene, and indolin-2-one derivatives. Further, vicinal difunctionalization was successfully carried out with the aid of the developed organocatalyst. Imperatively, all the aforementioned reactions were carried out in the aqueous medium. The reusability of the heterogeneous catalyst was also proved by carrying out the reaction with the recovered catalyst.

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Lignin-based naturally derived Brønsted acidic organocatalyst was utilized in the environmentally benign synthesis of biologically relevant indole derivatives, 4H-chromene, and indolin-2-one derivatives. All the aforementioned transformations were carried out in an environmentally benign aqueous medium.

This study reports a hydrotropic activity for synthesizing 1H-pyrazolo[1,2-b]phthalazine-5,10-dione through one pot four component aldehyde condensation, malononitrile, phthalic anhydride, and hydrazine hydrate. The simple and green hydrotropic synthetic approach offers numerous advantages such as non-toxic, inexpensive, mild reaction conditions, avoidance of harmful solvents, shorter reaction time, an excellent yield of products, simple workup, Chromatography-free, and eco-friendly. ¹H-NMR confirmed all the synthesized compounds.

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Quantum chemistry provides valuable insights into the structure and reactivity of heterocyclic organic compounds, facilitating the rational design of novel molecules with targeted functionalities. In this paper, structural features and chemical properties of 2-(2-phenyl-1,3-benzoxazol-7-yl)benzaldehyde, a benzoxazole-based heterocycle, were investigated. This multifaceted study combines crystallographic and quantum chemical methods to elucidate molecular geometry, crystal packing, and chemical reactivity of mono and dimeric forms. A rich network of intermolecular interactions, including nonclassical hydrogen bonds (C–H···O and C–H···N), π-stacking, and a unique C=O···π(ring) interaction, were found to govern the solid-state structure. Multi-approach quantum mechanics analysis using dispersion-corrected DFT (ωB97X-D/aug-cc-pVTZ) revealed the electronic features, energetics, and nature of these interactions. Furthermore, Conceptual DFT identified the molecule as a moderate electrophile and strong nucleophile in polar organic reactions, while Parr functions pinpointed favourable sites for electrophilic and nucleophilic attacks.

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Quantum chemistry provides valuable insights into the structure and reactivity of heterocyclic organic compounds, facilitating the rational design of novel molecules with targeted functionalities. In this paper, a benzoxazole-based heterocycle was computationally investigated using dispersion-corrected density functional theory. The focus was on noncovalent interactions and chemical reactivity in both mono and dimeric forms. This work not only introduces the molecule for future study, but also emphasizes the capability of used theoretical approaches in elucidating structure and reactivity within heterocyclic compounds.

A novel approach using a soft ionic atmosphere model for the diffusion of ions in concentrated aqueous electrolytes is developed to quantify molar conductivity ((Lambda)), diffusion coefficient (D), and relative viscosity ((eta _{text {r}}^*)). The entropy-driven expansion of the ionic atmosphere in the concentrated electrolyte is characterized through average ion size (({overline{r}}_{text {H}})), ionic screening length for point particle ions ((l_{text {D}})) and a hardness exponent ((gamma)). The radius ((l_{text {s}})) of expanded ionic sphere for finite size ions: (l_{text {s}}= l_{text {D}}(1+ ({overline{r}}_{text {H}} /l_{text {D}})^3)). (l_{text {s}}) circumvents the limitations of the classical Debye screening length ((kappa ^{-1})) in concentrated electrolytes. This model leads to a power law dependence of (Lambda), D and (eta _{text {r}}^*) on (l_{text {s}}). The extent of the hardness of the ionic atmosphere is characterized by an exponent (gamma), which is characteristic of an electrolyte solution and lies between 0.2–0.8. The expansion of the ionic sphere increases with concentration causing enhancement of the effective size of ions, resulting in the reduction in diffusion coefficient and molar conductivity. The model captures the experimental molar conductivity data for the fifteen salts in the aqueous medium.

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1,2,3-Triazole, 1,3-imidazole, and 1,3-thiazole are a class of organic heterocyclic compounds with notable applications in a diverse range of biological and pharmacological activities. Herein, we report the synthesis of molecules having these three moieties together. Each of the fused molecule was characterized with elemental analysis, melting point determination, FTIR, NMR, and mass spectrometry. The final fused molecules were screened for in vitro biological activities against a wide spectrum of microorganisms, such as gram-positive bacteria (E. coli, P. aeruginosa, S. aureus, S. phogenes), gram-negative bacteria (S. typhi, V. cholerae, B. subtilis, C. tetani), as well as fungus (C. albicans, A. niger, and A. Clavatus). Each of the compounds showed moderate to good activity which is comparable to commercially available drugs. Further, the molecular docking study on the crystal structure of the 43K ATPase domain of Thermus thermophilus gyrase B (PDB:1KIJ) and on crystal structure of penicillin-binding protein 4 from Staphylococcus aureus COL (PDB:3HUN) revealed strong binding affinities by the synthesized compounds. The ADME study also showed the drug likeliness of the compounds.

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Annulation reactions involving acetoxy allenoates and enolizable carbonyl substrates under DBU (DBU = 1,8-diazabicyclo[5.4.0]undec-7-ene) catalysis is described in this paper. Thus DBU catalyzed (3 + 3) annulation reactions of acetoxy allenoates with the bifunctional nucleophiles benzo-oxathiin-dioxide and phenylthiazolone afford fused 4H-pyrans. Both β′-acetoxy allenoates and δ-acetoxy allenoates undergo this annulation to give pyrano-oxathiines or pyrano-thiazoles.

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Acetoxy allenoates undergo facile (3 + 3) annulation with benzo-oxathiin-dioxide and phenylthiazolone under DBU catalysis to afford pyrano-oxathiines and pyrano-thiazoles.

A regioselective novel one-pot synthesis of heterocyclic purine derivative antiviral agent Ganciclovir in which initially guanine is treated with acetic anhydride in the presence of iodine (5%) to get diacetyl guanine intermediate, which undergoes in situ N-alkylation with AMDP in presence of catalytic acidic Amberlite IR-120 to get N-alkylated intermediate and finally deacetylation to get pure regioselective Ganciclovir, which is commercially viable and eco-friendly.

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We developed one-pot synthesis of antiviral drug Ganciclovir. Initially, Guanine is treated with acetic anhydride and iodine to yield diacetyl guanine 3. This intermediate then reacted with AMDP in the presence of acidic Amberlite IR-120 to obtain compound 5. Finally, deacetylation yields Ganciclovir 1, a commercially viable and eco-friendly process.

This study examines the intricate thermal decomposition of sweet sorghum bagasse, an agricultural residue with significant potential as a renewable energy and biofuel feedstock. Both slow and flash pyrolysis has been conducted over a temperature range of 300–450°C and flash pyrolysis experiments were performed through analytical pyrolysis via Py-GC/MS to comprehensively assess the pyrolysis behaviour and elucidate the biomass degradation pathways. In the slow pyrolysis experiments, sweet sorghum bagasse underwent controlled thermal decomposition at different temperatures (300–450°C), allowing for the investigation of the influence of temperature on product yields and compositions. The evolved volatile compounds and biochar products were analyzed to determine the impact of temperature on biomass degradation. The results revealed that 400°C is the optimum pyrolysis temperature for maximizing valuable bio-oil production with approximately 42 wt.% yields with an overall conversion of 73%. Various characterization techniques were employed to analyze the slow pyrolysis products, including GC-MS, TGA, FTIR, SEM, and XRD. Flash pyrolysis was employed to provide a detailed understanding of the rapid biomass breakdown under extreme heating conditions with a heating rate of 20°C/ms to complement the slow pyrolysis findings. This technique elucidated the primary mechanisms responsible for the degradation of sweet sorghum bagasse, shedding light on the fragmentation patterns and the formation of vital intermediate compounds during flash pyrolysis. These insights into the transient phenomena occurring during pyrolysis provide valuable information for developing efficient and sustainable biomass conversion processes.

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The pyrolysis behaviour of sweet sorghum bagasse (SSB) is comprehensively assessed using TGA, slow pyrolysis via lab scale glass tubular reactor and flash pyrolysis via analytical tool Py-GC/MS from 300–450°C. The study reveals the potential use of SSB as a renewable energy and biofuel feedstock.