Synthesis, biological evaluation and molecular modeling study of 5-trifluoromethyl-Δ²-pyrazoline and isomeric 5/3-trifluoromethylpyrazole derivatives as anti-inflammatory agents

Divergent Synthesis of Pyrazoles via Manganese Pincer Complex Catalyzed Acceptorless Dehydrogenative Coupling Reactions

This report detailed the synthesis of multi-substituted pyrazoles through the acceptorless dehydrogenative coupling (ADC) reaction catalyzed by a well-defined manganese(I)-pincer complex. Symmetrically substituted pyrazoles were synthesized by reacting 1,3-diols with hydrazines. Unsymmetrically substituted pyrazoles were selectively made via the ADC of primary alcohols with methyl hydrazones. Water and hydrogen are liberated as the green byproducts. The endurance of these methodologies has been presented by producing 30 substrates with varied functionalities. Model reactions were scaled up to demonstrate practicability. The reaction rate and order were measured to transparent the involvement of the reagents during catalysis. Control experiments elucidated the plausible reaction mechanisms.

Trifluoromethyl-β-dicarbonyls as Versatile Synthons in Synthesis of Heterocycles

Trifluoromethyl group relishes a privileged position in the realm of medicinal chemistry because its incorporation into organic molecules often enhances the bioactivity by altering pharmacological profile of molecule. Trifluoromethyl-β-dicarbonyls have emerged as pivotal building blocks in synthetic organic chemistry due to their facile accessibility, stability and remarkable versatility. Owing to presence of nucleophilic and electrophilic sites, they offer multifunctional sites for the reaction. This review covers a meticulous exploration of their multifaceted role, encompassing an in-depth analysis of mechanism, extensive scope, limitations and wide-ranging applications in diverse organic synthesis, covering the literature from the 21st century. This comprehensive review encapsulates the applications of trifluoromethyl-β-dicarbonyls and their synthetic equivalents as precursors of complex and diverse heterocyclic scaffolds, fused heterocycles and spirocyclic compounds having medicinal and material importance. Their potent synthetic utility in cyclocondensation reactions with binucleophiles, cycloaddition reactions, C-C bond formations, asymmetric multicomponent reactions using classical/solvent-free/catalytic synthesis have been presented. Influence of unsymmetrical trifluoromethyl-β-diketones on regioselectivity of transformation is also reviewed. This review will benefit the synthetic and pharmaceutical communities to explore trifluoromethyl-β-dicarbonyls as trifluoromethyl building blocks for fabrication of heterocyclic scaffolds having implementation into drug discovery programs in the imminent future.

Pyrazoles as Anti-inflammatory and Analgesic Agents: In-vivo and In-silico Studies

BACKGROUND

Pyrazole is a well-known nucleus in the pharmacy field with a wide range of other activities in addition to anti-inflammatory and analgesic, i.e., anticonvulsant, antiviral, and anticancer activities. There are well-known marketed drugs having pyrazole moiety as celecoxib, and lonazolac as COX-II inhibitors.

AIMS

We aim to synthesize better anti-inflammatory than existing ones. Thiophene is also known for its analgesic and anti-inflammatory action. Thus, the fusion of both gives better anti-inflammatory agents. In the present studies, derivatives from two series of pyrazole were prepared by reacting substituted chalcone (3a-3f) derivatives prepared from 2-acetyl thiophene. They substituted aromatic aldehydes with phenyl hydrazine to form (5a-5f) and with 2, 4-dinitro phenyl hydrazine giving compounds (6a-6f) separately.

METHODS

Purified and characterized pyrazoles have been analyzed for in-vivo analgesic and anti-inflammatory activities by using standard methods. Compounds 5e, 5f, and 6d were proved to be potent analgesics and series (5a-5f) was found to have anti-inflammatory action, which was further validated using docking and ADME studies.

RESULTS

The ADME profile of synthesized compounds was found to be satisfactory.

CONCLUSION

The synthesized compounds can serve as lead for further drug designing.

Recent Advancement in Drug Design and Discovery of Pyrazole Biomolecules as Cancer and Inflammation Therapeutics

Pyrazole, an important pharmacophore and a privileged scaffold of immense significance, is a five-membered heterocyclic moiety with an extensive therapeutic profile, viz., anti-inflammatory, anti-microbial, anti-anxiety, anticancer, analgesic, antipyretic, etc. Due to the expansion of pyrazolecent red pharmacological molecules at a quicker pace, there is an urgent need to put emphasis on recent literature with hitherto available information to recognize the status of this scaffold for pharmaceutical research. The reported potential pyrazole-containing compounds are highlighted in the manuscript for the treatment of cancer and inflammation, and the results are mentioned in % inhibition of inflammation, % growth inhibition, IC50, etc. Pyrazole is an important heterocyclic moiety with a strong pharmacological profile, which may act as an important pharmacophore for the drug discovery process. In the struggle to cultivate suitable anti-inflammatory and anticancer agents, chemists have now focused on pyrazole biomolecules. This review conceals the recent expansion of pyrazole biomolecules as anti-inflammatory and anticancer agents with an aim to provide better correlation among different research going around the world.

Intramolecular Appel Reaction of Trifluoromethylated β-Keto Diazos Enabling Assembly of Trifluoromethylpyrazoles

A method for the generation of trifluoromethylated β-keto diazos and their applications in intramolecular Appel type reactions are reported. The key success of this reaction is a diazo species as an N-nucleophile in Appel reactions. This reaction is conducted under mild conditions and has a broad substrate scope, affording trifluoromethylpyrazoles in ≤94% yields. This protocol represents a new type of Appel reaction and also a new reaction mode of fluoro diazoalkanes.

Substituted Pyrazoles and Their Heteroannulated Analogs-Recent Syntheses and Biological Activities

Pyrazoles are considered privileged scaffolds in medicinal chemistry. Previous reviews have discussed the importance of pyrazoles and their biological activities; however, few have dealt with the chemistry and the biology of heteroannulated derivatives. Therefore, we focused our attention on recent topics, up until 2020, for the synthesis of pyrazoles, their heteroannulated derivatives, and their applications as biologically active moieties. Moreover, we focused on traditional procedures used in the synthesis of pyrazoles.

Pyrazoles and Pyrazolines as Anti-Inflammatory Agents

The five-membered heterocyclic group of pyrazoles/pyrazolines plays important role in drug discovery. Pyrazoles and pyrazolines present a wide range of biological activities. The synthesis of the pyrazolines and pyrazole derivatives was accomplished via the condensation of the appropriate substituted aldehydes and acetophenones, suitable chalcones and hydrazine hydrate in absolute ethanol in the presence of drops of glacial acetic acid. The compounds are obtained in good yields 68-99% and their structure was confirmed using IR, ¹H-NMR, ¹³C-NMR and elemental analysis. The novel derivatives were studied in vitro for their antioxidant, anti-lipid peroxidation (AAPH) activities and inhibitory activity of lipoxygenase. Both classes strongly inhibit lipid peroxidation. Compound 2g was the most potent lipoxygenase inhibitor (IC₅₀ = 80 µM). The inhibition of the carrageenin-induced paw edema (CPE) and nociception was also determined, with compounds 2d and 2e being the most potent. Compound 2e inhibited nociception higher than 2d. Pyrazoline 2d was found to be active in a preliminary test, for the investigation of anti-adjuvant-induced disease (AID) activity. Pyrazoline derivatives were found to be more potent than pyrazoles. Docking studies of the most potent LOX inhibitor 2g highlight hydrophobic interactions with VAL126, PHE143, VAL520 and LYS526 and a halogen bond between the chlorine atom and ARG182.

Discovery of Anticancer Agents from 2-Pyrazoline-Based Compounds

As nitrogen-containing five-membered heterocyclic structural units, the substituted pyrazole derivatives have a broad spectrum of pharmacological activities, especially 4,5-dihydro-1H-pyrazoles that also commonly known as 2-pyrazolines. Since 2010, considerable studies have been found that the 2-pyrazoline derivatives possess potent anticancer activities. In the present review, it covers the pyrazoline derivatives reported by literature from 2010 till date (2010-2019). This review aims to establish the relationship between the anticancer activities variation and different substituents introduced into a 2-pyrazoline core, which could provide important pharmacophore clues for the discovery of new anticancer agents containing 2-pyrazoline scaffold.

Photocatalytic three-component radical cascade: a general route to heterocyclic-substituted alkyl sulfones

A photoredox-catalyzed three-component radical cascade reaction of β,γ-unsaturated oximes/hydrazones, the sulfur dioxide surrogate of DABCO·(SO2)2 and alkenes under mild conditions is developed.

[3 + 2] Cycloaddition of Nitrile Imines with Enamides: An Approach to Functionalized Pyrazolines and Pyrazoles

An efficient [3 + 2] cycloaddition of in situ generated nitrile imines with enamides has been established. A wide range of functionalized pyrazoline derivatives (53 examples) were obtained in moderate to good yields (up to 96%) under very mild conditions. This protocol features broad substrate scope, good functional group tolerance, and operational simplicity. Practical transformation of the products into useful pyrazoles via a one-pot process and the scalability of this protocol highlight the utility of this synthetic methodology.

Recent advancements in the development of bioactive pyrazoline derivatives

Pyrazolines remain privileged heterocycles in drug discovery. 2-Pyrazoline scaffold has been proven as a ubiquitous motif which is present in a number of pharmacologically important drug molecules such as antipyrine, ramifenazone, ibipinabant, axitinib etc. They have been widely explored by the scientific community and are reported to possess wide spectrum of biological activities. For combating unprecedented diseases and worldwide increasing drug resistance, 2-pyrazoline has been tackled as a fascinating pharmacophore to generate new molecules with improved potency and lesser toxicity along with desired pharmacokinetic profile. This review aims to summarizes various recent advancements in the medicinal chemistry of pyrazoline based compounds with the following objectives: (1) To represent inclusive data on pyrazoline based marketed drugs as well as therapeutic candidates undergoing preclinical and clinical developments; (2) To discuss recent advances in the medicinal chemistry of pyrazoline derivatives with their numerous biological significances for the eradication of various diseases; (3) Summarizes structure-activity relationships (SAR) including in silico and mechanistic studies to afford ideas for the design and development of novel compounds with desired therapeutic implications.

Synthesis, Characterization, Antimicrobial Activity and Anticancer of Some New Pyrazolo[1,5-a]pyrimidines and Pyrazolo[5,1-c]1,2,4-triazines

BACKGROUND

Pyrazole and its derivatives are known to exhibit significant biological and pharmacological activities such as anticancer, anti-inflammatory, antioxidant, antibacterial, analgesic, antiviral, antimicrobial, antifungal, anti-glycemic, antiamoebic, and antidepressive. Considering the immense biological properties, pyrazole is one of the most widely studied nitrogen- containing heterocyclic nuclei. Fused pyrazole derivatives are composed of the pyrazole nucleus attached to other heterocyclic moieties.

OBJECTIVE

The objective of this article is the synthesis of some new pyrazolo[1,5-a]pyrimidine and pyrazolo[5,1-c]1,2,4-triazine derivatives with potential anticancer and antimicrobial activities.

METHODS

The in vitro growth inhibitory rates (%) and inhibitory growth activity (as measured by IC50) of the newly synthesized compounds were determined against the MCF-7 human breast carcinoma cell line in comparison with the well-known anticancer drug doxorubicin as the standard, using the MTT viability assay. The data generated were used to plot a dose-response curve from which the concentration (μM) of tested compounds required to kill 50% of the cell population (IC50) was determined. Cytotoxic activity was expressed as the mean IC50 of three independent experiments. The difference between inhibitory activities of all compounds with different concentrations was statistically significant p < 0.001. All compounds were structurally characterized by different spectroscopic techniques EI-MS, 1H-NMR, and 13C-NMR, and evaluated for their anticancer and antimicrobial activities (antibacterial and antifungal).

RESULTS

Several pyrazolo[1,5-a]pyrimidine derivatives were synthesized from the reaction of 2-(4- (5-amino-1H-pyrazol-3-yl)phenyl)-1H-indene-1,3(2H)-dione with the appropriate active methylene compounds in boiling ethanol. Also, pyrazolo[5,1-c]triazines were obtained through the reaction of 2-(4-(5-(chlorodiazenyl)-1H-pyrazol-3-yl)phenyl)-1H-indene-1,3(2H)-dione with various active methylene compounds in ethanol containing sodium acetate at 0-5 oC. The structures of the newly synthesized compounds were elucidated on the basis of elemental analysis, spectral data, and alternative synthetic routes whenever possible. The newly synthesized compounds were evaluated for their antitumor activity against a breast cancer cell line (MCF-7) and a human colon cancer cell line (HCT-116). The results revealed that the tested compounds showed high variation in the inhibitory growth rates and activities against the tested tumor cell lines. All newly synthesized compounds screen towards microorganisms e.g. Gram-negative bacteria, Gram-positive bacteria, and Fungi.

CONCLUSION

2-(4-(5-Amino-1H-pyrazol-3-yl)phenyl)isoindoline-1,3-dione proved to be a useful precursor for the synthesis of various pyrazolo[1,5-a]pyrimidine and pyrazolo[5,1-c]-1,2,4- triazines. The structures of the newly synthesized compounds were confirmed by spectral data and elemental analyses. The newly synthesized compounds were tested in vitro against the MCF-7, HCT-116 human cancer cell line and compared with doxorubicin as the standard, using the MTT viability assay. Most of the tested compounds were found to have moderate to high anticancer activity.

5-Aminopyrazole as precursor in design and synthesis of fused pyrazoloazines

The condensation of 5-aminopyrazole with various bielectrophilic moieties results in the formation of pyrazoloazines, an interesting array of fused heterocyclic systems. The development of new synthetic routes towards pyrazoloazines for their biological and medicinal exploration is an attractive area for researchers throughout the world. The present review focuses on various synthetic methods developed in the last decade for the synthesis of differently substituted pyrazoloazines by a broad range of organic reactions by means of 5-aminopyrazole as a precursor.

Synthesis and Pharmacological Activities of Pyrazole Derivatives: A Review

Pyrazole and its derivatives are considered a pharmacologically important active scaffold that possesses almost all types of pharmacological activities. The presence of this nucleus in pharmacological agents of diverse therapeutic categories such as celecoxib, a potent anti-inflammatory, the antipsychotic CDPPB, the anti-obesity drug rimonabant, difenamizole, an analgesic, betazole, a H2-receptor agonist and the antidepressant agent fezolamide have proved the pharmacological potential of the pyrazole moiety. Owing to this diversity in the biological field, this nucleus has attracted the attention of many researchers to study its skeleton chemically and biologically. This review highlights the different synthesis methods and the pharmacological properties of pyrazole derivatives. Studies on the synthesis and biological activity of pyrazole derivatives developed by many scientists around the globe are reported.

Synthesis and Pharmacological Activities of Pyrazole Derivatives: A Review

Pyrazole and its derivatives are considered a pharmacologically important active scaffold that possesses almost all types of pharmacological activities. The presence of this nucleus in pharmacological agents of diverse therapeutic categories such as celecoxib, a potent anti-inflammatory, the antipsychotic CDPPB, the anti-obesity drug rimonabant, difenamizole, an analgesic, betazole, a H2-receptor agonist and the antidepressant agent fezolamide have proved the pharmacological potential of the pyrazole moiety. Owing to this diversity in the biological field, this nucleus has attracted the attention of many researchers to study its skeleton chemically and biologically. This review highlights the different synthesis methods and the pharmacological properties of pyrazole derivatives. Studies on the synthesis and biological activity of pyrazole derivatives developed by many scientists around the globe are reported.

Stoichiometry-controlled cycloaddition of nitrilimines with unsymmetrical exocyclic dienones: microwave-assisted synthesis of novel mono- and dispiropyrazoline derivatives

The Microwave-assisted 1,3-dipolar cycloaddition of (E,E)-1,3-bisarylidenetetral-2-ones with nitrilimines affords a series of mono- and dispiropyrazolines in good to excellent yields.

Synthesis and pharmacological evaluation of some new fluorine containing hydroxypyrazolines as potential anticancer and antioxidant agents

Breast cancer is probably the most prevalent cancer in women. The development of resistance to therapeutic agents and lack of targeted therapy for breast cancer cells provide motivation to identify new compounds for the treatment. With this objective in mind, a new series of 3-fluoro-4-methoxyphenyl group based 1,3,5-trisubstituted aryl-5-hydroxypyrazoline analogues 4a-l was synthesized through multi-step reaction sequence. The structures of the newly synthesized compounds were confirmed by IR, (1)H NMR, (13)C NMR, LC-MS and elemental analysis. They were screened for their in vitro anticancer and in vitro antioxidant activities. Among the tested compounds 4h, 4c and particularly 4i displayed promising cytotoxic effect on breast cancer cell lines. The compounds were also found to possess antioxidant activity when tested against DPPH free radical. Overall, this work has contributed to the development of promising leads for anticancer and antioxidant activities.

Synthesis, biological evaluation and docking study of maleimide derivatives bearing benzenesulfonamide as selective COX-2 inhibitors and anti-inflammatory agents

A series of maleimide analogs bearing benzenesulfonamide were synthesized (4a-r). The anti-inflammatory activity of synthesized derivatives was evaluated using carrageenan induced rat paw edema model. COX-1 and COX-2 potency was evaluated through in vitro cyclooxygenase assays. The results revealed that, compounds 4a, 4h, 4 j, 4 k and 4r had potent COX-2 percentage inhibition as well as in vivo anti-inflammatory activity. The potent compound 4 j was docked into the COX-2 active site to determine the probable binding model. The results of in vivo and in vitro studies demonstrate that phenyl ring with electron withdrawing groups on maleimide ring would generate more potent anti-inflammatory agents. Thus, these compounds can serve as potential leads for further anti-inflammatory studies.

Synthesis of pyrazoles containing benzofuran and trifluoromethyl moieties as possible anti-inflammatory and analgesic agents

Searching for new anti-inflammatory and analgesic agents, we have prepared a series of novel pyrazoles containing benzofuran and trifluoromethyl moieties. The pyrazole derivatives have been synthesized via two routes starting from 5-(3-(trifluoromethyl)phenyl azo) salicylaldehyde. The first route involved the synthesis of 2-acetylbenzofuran and then treatment with aldehydes to afford the corresponding chalcones. The cyclization of the latter chalcones with hydrazine hydrate led to the formation of new pyrazoline derivatives. The second route involved the synthesis of benzofuran-2-carbohydrazide and then treatment with formylpyrazoles, chalcones and ketene dithioacetal derivatives to afford the corresponding pyrazole derivatives. Some of the synthesized compounds exhibited anti-inflammatory and analgesic activities.

Study on the spectral and inclusion properties of a sensitive dye, 3-naphthyl-1-phenyl-5-(5-fluoro-2-nitrophenyl)-2-pyrazoline, in solvents and β-cyclodextrin

3-Naphthyl-1-phenyl-5-(5-fluoro-2-nitrophenyl)-2-pyrazoline (NPFP), a fluorogenic probe and its derivative NPFP-Phenylephrine were synthesized and their absorption and fluorescence properties were recorded in solvents of varying polarity. Spectroscopic studies reveal that, the solvatochromic behavior of the compounds depend not only on the polarity but also on the hydrogen-bonding properties of the solvents. The effects of β-cyclodextrin on the fluorescence properties of both compounds were studied. It was found that there is an enhancement in the fluorescence intensity of labeled drug (NPFP-Phenylephrine) in the presence of β-cyclodextrin. In the present study, the molecular motions of NPFP-Phenylephrine embedded in a β-cyclodextrin cavity have been investigated by fluorescence techniques in steady-state and time resolved modes.

Homologous 1,3,5-triarylpyrazolines: synthesis, CH⋯π interactions guided self-assembly and effect of alkyloxy chain length on DNA binding properties

The synthesis, CH⋯π interactions-driven self-assembled structure and DNA binding properties (10⁵–10⁶M⁻¹binding constants) of new homologous 1,3,5-triaryl-2-pyrazolines are reported.