5-(1-Aryl-3-(thiophen-2-yl)-1H-pyrazol-4-yl)-1H-tetrazoles: Synthesis, structural characterization, Hirshfeld analysis, anti-inflammatory and anti-bacterial studies

Phytotoxicity Study of (Amino)imidazo[1,2-a]pyridine Derivatives Toward the Control of Bidens pilosa, Urochloa decumbens, and Panicum maximum Weeds

In this work, several imidazo[1,2-a]pyridines were synthesized through the Groebke-Blackburn-Bienaymé three-component reaction (GBB-3CR), and their phytotoxicity was evaluated in vitro by the influence on the growth of wheat coleoptiles and three important agricultural seeds (Allium cepa, Lactuca sativa, and Solanum lycopersicum) at test concentrations of 1000, 300, 100, 30, and 10 μM. A structure-activity relationship was established, showing the importance of halogen groups at the ortho position of the attached aromatic ring and the presence of a cyclohexylamine group for greater activity. Post-modification of some GBB-3CR adducts was carried out, leading to imidazo[1,2-a]pyridine-tetrazole hybrids, which were also evaluated in these bioassays. The phytotoxicity on seed germination and growth bioassays demonstrated that A. cepa was the most susceptible seed, and the most affected parameters were the root and shoot lengths. The most active compound was also evaluated against Bidens pilosa, Urochloa decumbens, and Panicum maximum weeds under hydroponic conditions to assess its phytotoxic potential at a more advanced level of bioassays. Promising results were also achieved, in which the most affected growth factor by inhibition was the root growth, and a stimulus to shoot growth was noted, making it a promising hit in the search for new herbicides.

Synthesis and characterization of new pyrazole-tetrazole derivatives as new vasorelaxant agents

The synthesis of new functionalized tetrazole-pyrazole compounds is reported. They were fully characterized by spectroscopy and spectrometry methods. The vasorelaxant potency of these molecules was also investigated. All compounds showed a good vasorelaxant activity but the Compound 6 "ethyl 1-((2-(3-bromopropyl)-2H-tetrazol-5-yl)methyl)-5-methyl-1H-pyrazole-3-carboxylate" seems to have the highest effect, which reached 70% at 10^-4 M concentration. This effect was partially endothelium-dependent; also, the vasorelaxant pattern of this compound was quite similar to that of the verapamil.

Microwave-assisted Synthesis of Novel Pyrazole Derivatives and their Biological Evaluation as Anti-Bacterial Agents

AIMS AND OBJECTIVES

Microwave-assisted condensation of acetophenone 1 and aromatic aldehydes 2 gave chalcone analogs 3, which were cyclized to pyrazole derivatives 6a-f via the reaction with hydrazine hydrate and oxalic acid in the presence of the catalytic amount of acetic acid in ethanol.

MATERIALS AND METHODS

The structural features of the synthesized compounds were characterized by melting point, FT-IR, ¹H, ¹³C NMR and elemental analysis.

RESULTS

The antibacterial activities of the synthesized pyrazoles were evaluated against three gram-positive bacteria, such as Enterococcus durans, Staphylococcus aureus, Bacillus subtilis and two gram-negative bacteria such as Escherichia coli and Salmonella typhimurium.

CONCLUSION

All the synthesized pyrazoles showed relatively high antibacterial activity against S. aureus strain, and none of them demonstrated antibacterial activity against E. coli.

Evaluation of ursolic acid derivatives with potential anti-Toxoplasma gondii activity

Toxoplasma gondii is an important pathogen that causes serious public health problems. Currently, therapeutic drugs for toxoplasmosis cause serious side effects, and more effective and novel substances with relatively low toxicity are urgently needed. Ursolic acid (UA) has many properties that can be beneficial to healthcare. In this study, we synthesized eight series of UA derivatives bearing a tetrazole moiety and evaluated their anti-T. gondii activity in vitro using spiramycin as a positive control. Most of the synthesized derivatives exhibited better anti-T. gondii activity in vitro than UA, among which compound 12a exhibited the most potent anti-T. gondii activity. Furthermore, the results of biochemical parameter determination indicated that 12a effectively restored the normal body weight of mice infected with T. gondii, reduced hepatotoxicity, and exerted significant anti-oxidative effects compared with the findings for spiramycin. Additionally, our molecular docking study indicated that the synthesized compounds could act as potential inhibitors of T. gondii calcium-dependent protein kinase 1 (TgCDPK1), with 12a possessing strong affinity for TgCDPK1 via binding to the key amino acids GLU129 and TYR131.

Synthesis and anti-inflammatory effects of novel emodin derivatives bearing azole moieties

Twelve azole derivatives of emodin were designed to possess anti-inflammatory activity and synthesized via a two-step sequence composed of the Williamson ether reaction and N-alkylation. The anti-inflammatory properties of these compounds were evaluated in RAW264.7 cells by measuring lipopolysaccharide (LPS)-induced nitric oxide (NO) production. The introduction of imidazole and four carbons into the scaffold of emodin led to the discovery of the potent compound 7e, which showed the best inhibition of NO production among twelve analogs. In our experiential setting, the IC₅₀ of compound 7e in NO production is 1.35 µM, which is lower than that of indomethacin. Mechanically, compound 7e effectively inhibited the protein and messenger RNA expressions of cyclooxygenase-2 and inducible NO synthase, as well as that of the proinflammatory cytokine interleukin-6, and the cytokines interleukin-1β and tumor necrosis factor-α in the LPS-stimulated RAW 264.7 macrophages. Compound 7e exerted inhibitory effects on the nuclear factor κB pathway by reducing the LPS-induced phosphorylation of the inhibitor of NF-κB and the nuclear translation of p-p65. These results suggest the potential of compound 7e in improving inflammatory conditions and diseases.

Crystal structure, DFT calculation, Hirshfeld surface analysis and energy framework study of 6-bromo-2-(4-bromo-phen-yl)imidazo[1,2-a]pyridine

The title imidazo[1,2-a] pyridine derivative, C13H8Br2N2, was synthesized via a single-step reaction method. The title mol-ecule is planar, showing a dihedral angle of 0.62 (17)° between the phenyl and the imidazo[1,2-a] pyridine rings. An intra-molecular C-H⋯N hydrogen bond with an S(5) ring motif is present. In the crystal, a short H⋯H contact links adjacent mol-ecules into inversion-related dimers. The dimers are linked in turn by weak C-H⋯π and slipped π-π stacking inter-actions, forming layers parallel to (110). The layers are connected into a three-dimensional network by short Br⋯H contacts. Two-dimensional fingerprint plots and three-dimensional Hirshfeld surface analysis of the inter-molecular contacts reveal that the most important contributions for the crystal packing are from H⋯Br/Br⋯H (26.1%), H⋯H (21.7%), H⋯C/C⋯H (21.3%) and C⋯C (6.5%) inter-actions. Energy framework calculations suggest that the contacts formed between mol-ecules are largely dispersive in nature. Analysis of HOMO-LUMO energies from a DFT calculation reveals the pure π character of the aromatic rings with the highest electron density on the phenyl ring, and σ character of the electron density on the Br atoms. The HOMO-LUMO gap was found to be 4.343 eV.

Synthesis and evaluation of the HIF-1α inhibitory activities of novel ursolic acid tetrazole derivatives

The hypoxia-inducible factor-1α (HIF-1α) pathway has been implicated in tumor angiogenesis, growth, and metastasis. Therefore, the inhibition of this pathway is an important therapeutic target for the treatment of various types of cancers. Here, we designed and synthesized 31 ursolic acid (UA) derivatives containing a tetrazole moiety and evaluated them for their potential anti-tumor activities as HIF-1α transcriptional inhibitors. Of these, compound 14d (IC50 0.8 ± 0.2 µM) displayed the most potent activity and compounds 14a (IC50 4.7 ± 0.2 µM) exhibited the most promising biological profile. Analysis of the structure-activity relationships of these compounds with HIF-1α suggested that the presence of a tetrazole group located at C-28 of the UA derivatives was critical for their inhibitory activities.

Crystal structure and molecular docking studies of new pyrazole-4-carboxamides

Two pyrazol-4-carboxamides, 3-(difluoromethyl)-N-(mesitylcarbamoyl)-1-methyl-1H-pyrazole-4-carboxa-mide (7a) and 3-(difluoromethyl)-N-((3,5-dimethylphenyl) carbamoyl)-1-methyl-1H-pyrazole-4-carboxamide (7b) were synthesized and their structures were confirmed by the aid of 1H NMR and HRMS analyses. The structure of the pyrazole-4-carboxamide, 7a was also determined by X-ray diffraction. The preliminary activity results demonstrate that these two compounds exhibit good inhibitory activity against Botrytis cinerea. Further docking results indicated that the key active group is difluoromethyl pyrazole moiety.