Synthesis and antiviral activity of new pyrazole and thiazole derivatives

Crystal structure of N′-(4-nitrobenzylidene)-5-phenyl-1H-pyrazole-3-carbohydrazide, C17H13N5O3

C17H13N5O3, monoclinic, P21/c (no. 14), a = 20.1049(8) Å, b = 11.1534(4) Å, c = 6.8890(3) Å, β = 97.224(2)°, V = 1532.51(11) Å3, Z = 4, Rgt(F) = = 0.0451, wRref(F2) = 0.1153, T = 100 K.

Crystal structure of N′-(4-methoxybenzylidene)-5-phenyl-1H-pyrazole-3-carbohydrazide, C18H16N4O2

C18H16N4O2, triclinic, P1̅ (no. 2), a = 10.9734(4) Å, b = 11.8835(5) Å, c = 13.0996(5) Å, α = 78.581(2)°, β = 78.542(1)°, γ = 83.725(2)°, V = 1636.68(11) Å3, Z = 4, Rgt(F) = 0.0439, wRref(F2) = 0.1182, T = 100 K.

Design, synthesis, topoisomerase I & II inhibitory activity, antiproliferative activity, and structure-activity relationship study of pyrazoline derivatives: An ATP-competitive human topoisomerase IIα catalytic inhibitor

A series of pyrazoline derivatives (5) were synthesized in 92-96% yields from chalcones (3) and hydrazides (4). Subsequently, topo-I and IIα-mediated relaxation and antiproliferative activity assays were evaluated for 5. Among the tested compounds, 5h had a very strong topo-I activity of 97% (Camptothecin, 74%) at concentration of 100 μM. Nevertheless, all the compounds 5a-5i showed significant topo II inhibitory activity in the range of 90-94% (Etoposide, 96%) at the same concentration. Cytotoxic potential of these compounds was tested in a panel of three human tumor cell lines, HCT15, BT474 and T47D. All the compounds showed strong activity against HCT15 cell line with IC50 at the range of 1.9-10.4 μM (Adriamycin, 23.0; Etoposide, 6.9; and Camptothecin, 7.1 μM). Moreover, compounds 5c, 5f and 5i were observed to have strong antiproliferative activity against BT474 cell lines. Since, compound 5d showed antiproliferative activity at a very low IC50 thus 5d was then selected to study on their mode of action with diverse methods of ATP competition assay, ATPase assay and DNA-topo IIα cleavable complex assay and the results revealed that it functioned as a ATP-competitive human topoisomerase IIα catalytic inhibitor. Further evaluation of endogenous topo-mediated DNA relaxation in cells has been conducted to find that, 5d inhibited endogenous topo-mediated pBR322 plasmid relaxation is more efficient (78.0 ± 4.7% at 50 μM) than Etoposide (36.0 ± 1.7% at 50 μM).

Synthesis and Anti-Inflammatory Activity of Some O-Propargylated-N-acetylpyrazole Derived from 1,3-Diarylpropenones

In search of novel effective potent therapeutic agents delivered by oral route for inflammation treatment, some novel O-propargylated-N-acetylpyrazole analogs (5a-j) were prepared by treating N-acetylpyrazole (4a-j) derived from 1,3-diarylpropenones (3a-j) with propargyl bromide. Claisen-Schmidt condensation of a series of substituted aryl ketones 1 and benzaldehydes 2 in glacial acetic acid afforded 1,3-diarylpropenones which on further treatment with hydrazine hydrate in acetic acid under reflux conditions afforded 1-acetyl-3,5-diaryl-4,5-dihydro(1H)pyrazoles (4a-j). The products were characterized by using spectroscopic techniques such as IR and NMR. In addition, the in vivo anti-inflammatory activity of the synthesized compounds was determined using the carrageenan-induced paw oedema method in rats.

Synthetic approaches, structure activity relationship and biological applications for pharmacologically attractive pyrazole/pyrazoline-thiazolidine-based hybrids

The features of the chemistry of 4-thiazolidinone and pyrazole/pyrazolines as pharmacologically attractive scaffolds were described in a number of reviews in which the main approaches to the synthesis of mentioned heterocycles and their biological activity were analyzed. However, the pyrazole/pyrazoline–thiazolidine-based hybrids as biologically active compounds is poorly discussed in the context of pharmacophore hybrid approach. Therefore, the purpose of this review is to summarize the data about the synthesis and modification of heterocyclic systems with thiazolidine and pyrazoline or pyrazole fragments in molecules as promising objects of modern bioorganic and medicinal chemistry. The description of biological activity was focused on SAR analysis and mechanistic insights of mentioned hybrids.

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Synthesis and chemistry of pyrazole/pyrazoline–thiazolidine-based hybrids.

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A diverse spectrum of pyrazole/pyrazoline–thiazolidine-based hybrids biological activities has been presented.

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Structure activity relationship of pyrazole/pyrazoline–thiazolidine-based hybrids for different activities has been discussed.

Current status of pyrazole and its biological activities

Pyrazole are potent medicinal scaffolds and exhibit a full spectrum of biological activities. This review throws light on the detailed synthetic approaches which have been applied for the synthesis of pyrazole. This has been followed by an in depth analysis of the pyrazole with respect to their medical significance. This follow-up may help the medicinal chemists to generate new leads possessing pyrazole nucleus with high efficacy.

Influence of the non-conjugated 5-position substituent of 1,3,5-triaryl-2-pyrazoline-based photosensitizers on the photophysical properties and performance of a dye-sensitized solar cell

We report the effect of the non-conjugated 5-position substituent of pyrazoline-based photosensitizers on the photophysical characteristics and performance of dye-sensitized solar cells (DSSCs).

Eco-friendly grinding synthesis of a double-layered nanomaterial and the correlation between its basicity, calcination and catalytic activity in the green synthesis of novel fused pyrimidines

The synthesis of hydrotalcite using Al : Mg molar ratios of 1.0 : 3.0 by a grinding method at room temperature is reported.

Crystal structure of N'-di-phenyl-methyl-idene-5-methyl-1H-pyrazole-3-carbo-hydrazide

In the title compound, C18H16N4O, the planes of the phenyl rings are approximately perpendicular to each other [dihedral angle = 78.07 (8)°] and form dihedral angles of 56.43 (8) and 24.59 (8)° with the pyrazole ring. In the crystal, mol-ecules are linked by N-H⋯O hydrogen bonds to form one-dimensional chains parallel to the [010] direction.

Synthesis and antiviral activity of some new bis-1,3-thiazole derivatives

Treatment of 3-phenyl-1,3-thiazolidin-4-one derivative 1 with phenylisothiocyanate in DMF, in the presence of potassium hydroxide, at room temperature gave the non-isolable potassium salt 2. The in-situ reaction of 2 with differently substituted N-aryl hydrazonoyl chlorides 3, 7a-d and 14a-d afforded the corresponding 2-(pyrazolyl)thiazolylimino-5-(thiadiazolylidene)thiazolidin-4-one derivatives 6, 10a-d and 17a-d, respectively. Reaction of 2 with further α-haloketones yielded the 4-(pyrazolyl)thiazolylimino-bis-thiazolidine derivatives 22, 25 and 26. Single crystal X-ray analysis was used in structure elucidation of the products. The in-vitro antiviral screening against four viruses (Poliovirus, Influenza A (H1N1) virus, Hepatitis B virus and Hepatitis C virus) for the obtained compounds was examined. Structure activity relationship (SAR) was also studied. The goal of the work was achieved in discovering a very active compound 10a as anti HCV agent (EC50 0.56 μM).

Design, synthesis and herbicidal evaluation of novel 4-(1H-pyrazol-1-yl)pyrimidine derivatives

BACKGROUND

A series of novel pyrazolylpyrimidine derivatives were designed, synthesised and characterised by IR, (1) H NMR, (13) C NMR, mass spectroscopy and elemental analysis. The herbicidal activities of 30 pyrazolylpyrimidine derivatives were assessed.

RESULTS

Nine compounds caused good herbicidal activity for Pennisetum alopecuroides L. Among them, N-ethyl-6-[5-methyl-3-(trifluoromethyl)-1H-pyrazol-1-yl]-pyrimidin-4-amine exhibited the strongest inhibitory activity against the root growth of P. alopecuroides, with an IC50 of 1.90 mg L(-1) . 2-Methyl-4-[5-methyl-3-(trifluoromethyl)-1H-pyrazol-1-yl]-6-(prop-2-yn-1-yloxy)pyrimidine produced the highest inhibition of chlorophyll level in seedlings of P. alopecuroides (IC50  = 3.14 mg L(-1) ).

CONCLUSION

The structure-activity relationship indicated that the alkynyloxy group at the 6-position on the pyrimidine ring played a very important role for bleaching activities. When the alkynyloxy group was replaced by alkoxy, amino, alkylthio and alkylsulfonyl groups, the bleaching activities of the compounds were diminished. However, the compounds substituted by an amino at the 6-position of the pyrimidine ring exhibited excellent inhibition activities against weed root growth.

Crystal structure of (4Z)-4-[(di-methyl-amino)-methyl-idene]-3,5-dioxo-2-phenyl-pyrazolidine-1-carbaldehyde

In the title compound, C13H13N3O3, the pyrazolidine ring adopts a shallow envelope conformation, with the carbonyl C atom closest to the benzene ring as the flap [deviation of 0.126 (1) Å from the plane through the remaining atoms (r.m.s. deviation = 0.011 Å)]. The dihedral angle between the pyrazolidine ring (all atoms) and the benzene ring is 51.09 (4)°. An extremely short (2.08 Å) intra-molecular C-H⋯O contact is seen. In the crystal, mol-ecules are linked by C-H⋯O bonds, generating [010] chains. Extremely weak C-H⋯π inter-actions are also observed.

Thiophene and benzodioxole appended thiazolyl-pyrazoline compounds: Microwave assisted synthesis, antimicrobial and molecular docking studies

A novel series of thiophene and benzodioxole appended thiazolyl-pyrazoline derivatives have been designed, synthesized and evaluated against different bacteria and fungi. The antimicrobial activity of the synthesized compounds were screened using MIC method and were proved synthesized compounds 7o, 7r and 7t to show good antimicrobial activity against bacteria and fungi. In silico molecular docking studies revealed that all the synthesized molecules showed good binding energy toward the target receptor DNA topoisomerase IV, ranging from -10.42 to -11.66 kcal/mol.

Recent applications of 1,3-thiazole core structure in the identification of new lead compounds and drug discovery

1,3-Thiazole is one of the most important scaffolds in heterocyclic chemistry and drug design and discovery. It is widely found in diverse pharmacologically active substances and in some naturally-occurring compounds. Thiazole is a versatile building-block for lead generation, and is easily access of diverse derivatives for subsequent lead optimization. In the recent years, many thiazole derivatives have been synthesized and subjected to varied biological activities. In this article we intended to review the most important biological effects of thiazole-based compounds and highlight their roles in new leads identification and drug discovery. This article is also intended to help researches for finding potential future directions on the development of more potent and specific analogs of thiazole-based compounds for various biological targets.

Design and Synthesis of Pyrazole-3-one Derivatives as Hypoglycaemic Agents

Pyrazole-3-one compounds were designed on the basis of docking studies of previously reported antidiabetic pyrazole compounds. The amino acid residues found during docking studies were used as guidelines for the modification of aromatic substitutions on pyrazole-3-one structure. Depending on the docking score, the designed compounds were selectively prioritized for synthesis. The synthesized compounds were subjected to in vivo hypoglycemic activity using alloxan induced diabetic rats and metformin as a standard. Compound 4 having sulphonamide derivative was found to be the most potent compound among the series.

An efficient aqueous phase synthesis of benzimidazoles/benzothiazoles in the presence of β-cyclodextrin

Benzimidazoles/benzothiazoles were synthesized in water under neutral conditions by the reaction of aromatic aldehydes, o-phenylenediamine/2-amino thiophenol mediated by β-cyclodextrin in high yields.

3-(1-Phenyl-4-((2-(4-arylthiazol-2-yl)hydrazono)methyl)-1H-pyrazol-3-yl)-2H-chromen-2-ones: one-pot three component condensation, in vitro antimicrobial, antioxidant and molecular docking studies

A series of novel pyrazolyl coumarin bearing 2,4-disubstituted thiazole derivatives (5a-l) have been synthesized efficientlyviathree-component one-pot manner by Hantzsch condensation.

Antimicrobial applications of transition metal complexes of benzothiazole based terpolymer: synthesis, characterization, and effect on bacterial and fungal strains

Terpolymer of 2-amino-6-nitro-benzothiazole-ethylenediamine-formaldehyde (BEF) has been synthesized and characterized by elemental analysis and various spectral techniques like FTIR, UV-Visible, and ¹H and ¹³C-NMR. The terpolymer metal complexes were prepared with Cu²⁺, Ni²⁺, and Zn²⁺ metal ions using BEF terpolymer as a ligand. The complexes have been characterized by elemental analysis and IR, UV-Visible, ESR, ¹H-NMR, and ¹³C-NMR spectral studies. Gel permeation chromatography was used to determine the molecular weight of the ligand. The surface features and crystalline behavior of the ligand and its complexes were analyzed by scanning electron microscope and X-ray diffraction methods. Thermogravimetric analysis was used to analyze the thermal stability of the ligand and its metal complexes. Kinetic parameters such as activation energy (E_a) and order of reaction (n) and thermodynamic parameters, namely, ΔS, ΔF, S*, and Z, were calculated using Freeman-Carroll (FC), Sharp-Wentworth (SW), and Phadnis-Deshpande (PD) methods. Thermal degradation model of the terpolymer and its metal complexes was also proposed using PD method. Biological activities of the ligand and its complexes were tested against Shigella sonnei, Escherichia coli, Klebsiella species, Staphylococcus aureus, Bacillus subtilis, and Salmonella typhimurium bacteria and Aspergillus flavus, Aspergillus niger, Penicillium species, Candida albicans, Cryptococcus neoformans, Mucor species fungi.

Synthesis and biological evaluation of compounds which contain pyrazole, thiazole and naphthalene ring as antitumor agents

A series of compounds which contain pyrazole, thiazole and naphthalene ring (1a-7a, 1b-7b, 1c-7c, 1d-7d) were firstly synthesized and their anti-proliferative activity, EGFR inhibitory activity, cytotoxicity and inhibition to Hela cell migration were evaluated. Compound 2-(3-(3,4-dimethylphenyl)-5-(naphthalen-2-yl)-4,5-dihydro-1H-pyrazol-1-yl)thiazol-4(5H)-one (7d) displayed the most potent inhibitory activity (IC50=0.86μM for Hela and IC50=0.12μM for EGFR). Structure-activity relationship (SAR) analysis showed that the anti-proliferative activity was affected by A-ring-substituent (-OCH3>-CH3>-H>-Br>-Cl>-F). Docking simulation of compound 7d into EGFR active site showed that naphthalene ring of 7d with LYS721 formed two p-π bonds, which enhanced antitumor activity. Therefore, compound 7d may be developed as a potential antitumor agent.

Novel anti-HIV-1 NNRTIs based on a pyrazolo[4,3-d]isoxazole backbone scaffold: design, synthesis and insights into the molecular basis of action

Design and synthesis of novel anti-HIV-1 NNRTIs based on a pyrazolo[4,3-d]isoxazole backbone scaffold.