Amino Pyrazole Research Articles

Exploring The Antimicrobial Potential of Novel 1,2,4‒Triazole Conjugates with Pyrazole: Synthesis, Biological Activity and In Silico Docking.

In the present study, a new series of 1,2,4‒triazole linked pyrazole hybrids (5a‒5l) were synthesized from dimethyl amino pyrazole (1) in good yield by three-step reaction. The chemical structures of the resulted compounds were thoroughly elucidated using spectral analyses such as IR, 1H-NMR, 13C-NMR, mass spectra and elemental analysis. The target compounds were screened for their antimicrobial activities against the various standard pathogen strains, Gram‒(‒ve) (E. coli, P. aeruginosa, K. pneumoniae, A. baumannii), and Gram‒(+ve) (S. aureus,S. faecalis) microorganisms. According to the results obtained, in particular, compounds 5b, 5f, 5h and 5j was effective at inhibiting the antibacterial growth of all the bacteria's, having MIC values ranging 0.983‒14.862 mg/mL and compared to moxifloxacin (1.391‒22.01 mg mL-1). The most active compounds were chosen to interact with the DNA gyrase and topoisomerase-IV targets via molecular docking. These selected ligands interacted with PDB targets 2XCO, 1S16 and docked into the active site of amino acids Ala-269, Gly-413, Asn-405, Ser-1182, Thr-1185, His-1186, His-1186, Lys-1189, and Trp-1213.The pharmacokinetic properties, stability, and drug-likeness parameters of all target molecules were estimated using SwissADME and PkCSM protocols. The current study used in silico approaches combining e-pharmacophore modeling and structure-based molecular docking of targets to identify antimicrobial agents.

Synthesis and Evaluation of diaryl ether modulators of the leukotriene A4 hydrolase aminopeptidase activity

Activation of the aminopeptidase (AP) activity of leukotriene A4 hydrolase (LTA4H) presents a potential therapeutic strategy for resolving chronic inflammation. Previously, ARM1 and derivatives were found to activate the AP activity using the alanine-p-nitroanilide (Ala-pNA) as a reporter group in an enzyme kinetics assay. As an extension of this previous work, novel ARM1 derivatives were synthesized using a palladium-catalyzed Ullmann coupling reaction and screened using the same assay. Analogue 5, an aminopyrazole (AMP) analogue of ARM1, was found to be a potent AP activator with an AC50 of 0.12 μM. An X-ray crystal structure of LTA4H in complex with AMP was refined at 2.7 Å. Despite its AP activity with Ala-pNA substrate, AMP did not affect hydrolysis of the previously proposed natural ligand of LTA4H, Pro-Gly-Pro (PGP). This result highlights a discrepancy between the hydrolysis of more conveniently monitored chromogenic synthetic peptides typically employed in assays and endogenous peptides. The epoxide hydrolase (EH) activity of AMP was measured in vivo and the compound significantly reduced leukotriene B4 (LTB4) levels in a murine bacterial pneumonia model. However, AMP did not enhance survival in the murine pneumonia model over a 14-day period. A liver microsome stability assay showed metabolic stability of AMP. The results suggested that accelerated Ala-pNA cleavage is not sufficient for predicting therapeutic potential, even when the full mechanism of activation is known.

Anti-parkinsonian, anti-inflammatory, anti-microbial, analgesic, anti-hyperglycemic and anticancer activities of poly-fused ring pyrimidine derivatives

Purpose: To investigate the anti-inflammatory, anti-cancer, anti-parkinsonian, anti-microbial, analgesic, and anti-hyperglycemic properties of a variety of poly-fused pyrimidine derivatives.
 Methods: A novel series of fused pyrimidine derivatives 1-6 were synthesized by reacting amino pyrazole derivatives with active methylene derivatives to give the corresponding compounds 1-6. Anti-parkinsonian activity was investigated with benzotropene as a reference drug, anti-inflammatory effect in mice was evaluated using carrageenan in paw edema with indomethacin as reference drug, anti-microbial activity was assessed using nutritional agar with ciprofloxacin and ketoconazole as reference drugs, analgesic activity was evaluated using valdecoxib as reference drug, anti-hyperglycemic activity was investigated using alloxan and sucrose models (SLM) with pioglitazone as reference drug and anticancer activity was investigated using the MTT micro-cultured tetrazolium assay method with doxorubicin as reference drug.
 Results: Pyrimidine derivatives 1-6 possess significant active anti-parkinsonian, anti-inflammatory, anti-microbial, analgesic, anti-hyperglycemic and anticancer activities in comparison to the reference drugs used for each model. Compared to Benzotropene®, compounds 1 and 3 showed a significantly stronger anti-parkinsonian activity (p < 0.03). Compound 3 showed a significantly stronger anti-inflammatory effect than Indomethacin® (p < 0.05). Compounds 5 and 6 exhibited significant anti- microbial activity compared to ciprofloxacin® (p < 0.05). Compounds 4 and 6 exhibited significantly improved analgesic activity as compared to Valdecoxib® (p < 0.01). Compounds 1 and 3 exhibited significantly higher anti-hyperglycemic effects in SLM model when compared to pioglitazone® (p < 0.02). Compound 5 demonstrated the highest activity against human colon cancer cell line (HT-29) and human prostate cancer cell line (DU145), and also, significantly improved level of efficacy against human lung cancer cell line (A549) compared to Doxorubicin® (p < 0.02). 
 Conclusion: Using the six pyrimidine derivatives 1 - 6 as a lead molecule, a novel class of clinically beneficial anti-cancer, anti-inflammatory, anti-microbial, analgesic, and anti-hyperglycemic drugs may be produced.

Synthesis of Selenocyanates and Selenoethers of Amino Pyrazoles and Amino Uracils by In Situ Triselenium Dicyanide from Malononitrile and Selenium Dioxide.

Herein, we report an efficient method for synthesis of novel selenocyanates of amino pyrazole, amino uracil, and amino isoxazole derivatives using in situ triselenium dicyanide from the combination of malononitrile and selenium dioxide in DMSO medium. Using the same combination but changing the stoichiometry of reagents and sequence of addition and temperature, symmetrical selenoethers of amino pyrazoles and amino uracils were prepared in good yields. Furthermore, selenocyanates of amino pyrazoles were utilized for the synthesis of corresponding alkynyl selenides in the presence of CuI and Cs2CO3. The salient features of this methodology are inexpensive starting materials, short reaction time, and good to very good yields. This method is also applicable for the gram-scale synthesis of selenocyanates of amino pyrazoles and amino uracils.

Synthesis, theoretical calculations, X-ray, HS and energy framework analysis, molecular docking of amino pyrazole containing azo dye and its inhibition activity of COVID-19 main protease

The synthesis and characterization of 5-Amino-4-Phenylazo-3-Methyl-1-(2-hydroxyethyl) Pyrazole (AD2a) were investigated in our study. The novel synthesized pyrazole-based disperse diazo dye has been elucidated by using UV–Vis, FT-IR, elemental analysis, LC/MS-MS, NMR and X-ray analysis. The AD2a molecule containing pyrazole and phenyl rings, hydroxy‑ethyl and azo group moieties crystallized in the orthorhombic space group Pbca. The crystal structures of AD2a are consolidated by N(3)-H(3A)⋯O(1) and O(1)-H(1)⋯N(5) intermolecular hydrogen bonds. The geometry of AD2a has been optimized with the DFT calculation B3LYP/6–31G(d,p) level and it has been observed that the obtained results give very good results with the X-ray diffraction data. The theoretical vibrational analysis, frontier orbital energies, electronic absorption spectrum, electronic properties, global reactivity descriptors and other theoretical parameters were obtained by using the same DFT method. Additionally, Hirshfeld surface analysis (HSA) with 2D fingerprint plots (FP) was performed to estimate contacts and the energy framework diagrams of AD2a (Eele, Edis and Etot) were determined. The inhibitor-receptor relationship established by the molecular docking study confirmed the inhibition activity of the AD2a construct against COVID-19. It showed that the AD2a molecule, shown as a drug candidate, binds strongly to SARS-CoV-2 (Mpro) (-6.5 kcal/mol) receptors.

Highly Reversible “Off‐On‐Off” Dual‐channel Fluorescence Probe Based on Amino Pyrazole and Phenothiazine for Sensing Extremely Alkaline Solution

AbstractAcid‐base balance is related to many cell functions, and its disorders can lead to many diseases. Real‐time detection of intracellular pH fluctuation is very important to prevent many diseases and environmental water samples. Here, we report a dual‐channel fluorescence probe PTZ‐aminopyrazole based on low‐cost phenothiazine and 3‐aminopyrazole, which can detect pH fluctuation highly sensitively through protonation under acidic condition and deprotonation under alkaline condition. The probe exhibits a fluorescence intensity and UV absorbance characteristics in the extreme acidity range of 2.6‐5.5 and especially in the extreme alkaline range of 11.1‐13.8, respectively. In addition, PTZ‐ aminopyrazole has high pH‐selective reaction to metal ions, good reversibility and excellent photostability. Furthermore, PTZ‐aminopyrazole can be fixed on a test paper, which shows a rapid and reversible colorimetric response to HCl/NaOH vapor with naked‐eye.

Special Focus Issue - Targeted protein degradation: a new paradigm in medicinal chemistry.

Special Focus Issue - Targeted protein degradation: a new paradigm in medicinal chemistry.

Visible Light-Mediated C(sp2)-H Selenylation of Amino Pyrazole and Amino Uracils in the Presence of Rose Bengal as an Organophotocatalyst.

Herein, we report an efficient methodology for the synthesis of alkyl, benzyl, and phenyl selenoethers of aminopyrazoles and aminouracils by C(sp2)-H functionalization in the presence of visible light and Rose Bengal as an organophotocatalyst. The reaction of amino pyrazole/iosothiazole/isoxazole or amino uracils with 0.5 equivalent of diphenyl/dibenzyl/diethyl diselenides in the presence of visible light in acetonitrile medium and a catalytic amount of Rose Bengal provided the corresponding phenyl, benzyl, or ethyl selenoethers in good to very good yields. We have also utilized some of the selenylated aminopyrazoles for the preparation of pyrazole-fused dihydropyrimidines tethered with arylselenoethers by a catalyst-free one-pot three-component reaction. The notable features of this methodology are metal-free reaction conditions, good to very good yields, use of an organic photocatalyst, and wide substrate scope; it is also applicable to gram-scale synthesis and provides selenoethers of medicinally important heterocycles such amio-pyrazole, isoxazole, isothiazole, and uracils.

Metal- and Solvent-Free Cascade Reaction for the Synthesis of Amino Pyrazole Thioether Derivatives.

We developed an iodine-mediated cascade strategy to synthesize amino pyrazole thioether derivatives (11) in the absence of metals as well as solvents. The present approach provides amino pyrazole thioethers in a highly selective manner without the formation of diaryl sulfide and sulfenyl-enaminonitrile with broad substrate scope. The reactivity of nine sulfenylation sources and synthetic applications of the synthesized compounds have been demonstrated. Thus, the overall iodine-mediated multicomponent reaction (MCR) is more economically feasible, efficient, and environmentally benign.

Microwave Assisted Synthesis of Pyrazolo[1,5-a]pyrimidine, Triazolo[1,5-a]pyrimidine, Pyrimido[1,2-a]benzimdazole, Triazolo[5,1-c][1,2,4]triazine and Imidazo[2,1-c][1,2,4]triazine

Background: This paper describes the synthesis of novel fused heterocycles, from the reaction 2-cyano-N-cyclohexyl-3-acrylamide derivatives 5a-f with nitrogen nucleophilic reagents, which carried out under microwave irradiation. Reactivity of 3 towards diazonium amines salts to afford hydrazones undergo cyclization to give amino pyrazole and the fused heterocyclic compounds incorporating cyclohexyl moiety. The synthesized compounds excellently utilized microwave irradiation in short time and high yield. Methods: Synthesis of Fused heterocycles derivatives from 2-cyano-N-cyclohexyl acetamide utilizing Microwave irradaition. Results: Regioselective facile synthesis of innovative heterocycles from the reaction of 2-cyano-Ncyclohexyl acetamide (3) with appropriate aldehydes to afford the corresponding acrylamide derivatives 5a-f under microwave irradiation. Acrylamides 5 reacts with hydrazine derivatives affording the corresponding pyrazole derivatives 7a and 7b, furthermore the treatment of acrylamides 5 with 2-amino benzimidazole, amino pyrazole, and aminotriazole derivatives to gives corresponding pyrimido[1,2-a]benzimdazole 10, pyrazolo[1,5-a]pyrimidine 12 and triazolo[1,5-a]pyrimidine 14; respectively in good yield. Reactivity of 3 towards diazonium amines salts afforded hydrazones derivatives, which undergo cyclization to give the corresponding derivatives 19a and the fused pyrazolo[5,1-c][1,2,4]triazine 22, triazolo[5,1-c][1,2,4]triazine 24 and imidazo[2,1-c][1,2,4]triazine 28 incorporating cyclohexyl moiety. Conculsion: In this investigation, we have synthesized innovative pyrimido[1,2-a]benzimdazole, and triazolo[1,5-a]pyrimidine, pyrazolo[1,5-a]pyrimidine, 2-amino benzimidazole, amino pyrazole, aminotriazole, fused pyrazolo[5,1-c][1,2,4]triazine, triazolo[5,1-c][1,2,4]triazine and imidazo[2,1- c][1,2,4]triazine derivatives incorporating cyclohexyl moiety utilizing microwave irradiation. The compounds were obtained under microwave reaction in excellent yield in a short reaction time.

Synthesis and DFT study of novel pyrazole, thiophene, 1,3-thiazole and 1,3,4-thiadiazole derivatives

Regioselective facile synthesis of innovative heterocycles from the reaction of 2-cyano-N-cyclohexylacetamide (3) with hydrazonoyl chloride (4) in basic condition afforded amino pyrazole derivative 6. The behavior of acetamide 3 with phenylisothiocyanate in DMF/KOH surveyed by addition of the α-halo ketones to yeild the corresponding thiophene derivative 13a, 13b, 16, 18 and 1,3-thiazoles 21. Reaction of intermediate potassium salt 9 with hydrazonoyl chloride 22a-e furnished the corresponding 1,2,4-thiadiazoles 24a-e. Density functional theory (DFT) calculations at the B3LYP and HF techniques combined with 6-31G(d) basis set to investigate the equilibrium geometry of the innovative compound pyrazoles 6 and the stability affording of HOMO/LUMO molecular orbitals.

N-Acetyl-3-aminopyrazoles block the non-canonical NF-kB cascade by selectively inhibiting NIK.

NF-κB-inducing kinase (NIK), an oncogenic drug target that is associated with various cancers, is a central signalling component of the non-canonical pathway. A blind screening process, which established that amino pyrazole related scaffolds have an effect on IKKbeta, led to a hit-to-lead optimization process that identified the aminopyrazole 3a as a low μM selective NIK inhibitor. Compound 3a effectively inhibited the NIK-dependent activation of the NF-κB pathway in tumour cells, confirming its selective inhibitory profile.

Synthesis Characterization and Biological Evaluation of Some Novel Amino Pyrazole Derivatives

Synthesis Characterization and Biological Evaluation of Some Novel Amino Pyrazole Derivatives

Synthesis of Thio and Selenoethers of Cyclic β-Hydroxy Carbonyls and Amino Uracils: A Metal-Free Regioselective I2 /DMSO Mediated Reaction

A simple and practical method has been developed using I2/DMSO for the construction of C−S and C−Se bonds in pharmaceutically important cyclic β-hydroxy carbonyls such as 4-hydroxy-6-methyl-2H-pyran-2-one, 4-hydroxy-1-methylquinolin-2(1H)-one, quinoline-2,4-diol and heterocyclic enamines such as amino uracil and amino pyrazole derivatives under mild reaction conditions. A series of thio and seleno ethers have been synthesized directly from thiols and selenols in the presence of in situ iodonium ion generated from the I2/DMSO combination in good to very good yields. This metal-free dehydrogenative C−S and C−Se coupling reaction goes via C(sp2)-H bond activation and works under conventional as well as microwave heating. Under microwave conditions, reactions complete within 15 minutes with very good yields.

XRD, IR and XAFS studies of cobalt complexes having amino pyrazole dicarboxylate (APD) as ligand

X-ray absorption fine structure spectroscopic (XAFS) studies have been done on two cobalt complexes using APD (diethyl 4-amino-1-phenyl-1H-pyrazole-3,5 dicarboxylate) as ligand. The X-ray absorption spectra of the complexes have been recorded on beam line of synchrotron at Raja Ramanna Centre for Advanced Technology (RRCAT), Indore (India). The X-ray diffraction of the samples has also been carried out. FTIR studies of two samples were also reported in the present communication.

Synthesis and spectroscopy studies of the inclusion complex of 3-amino-5-methyl pyrazole with beta-cyclodextrin

Amino pyrazole belongs to anti-inflammatory class, and is characterized by a low solubility in water. (In order to increase its solubility in water, inclusion complex of amino pyrazole with β-CD was obtained.) The inclusion complex obtained between AMP and β-cyclodextrin, was characterized by FT-IR, 1H NMR, 1H–1H NOESY, 13C NMR, DEPT, XHCOR, spectra, through TG analysis, DTA, DSC and Scanning Electron Microscopy (SEM). The stoichiometry of inclusion complex is 1:1 (guest–host) and K stability is 1.1×104M−1.

Polyethylene glycol (PEG-400): an efficient and recyclable reaction medium for the synthesis of pyrazolo[3,4-b]quinoline derivatives

A simple, efficient, and eco-friendly synthetic protocol has been developed via one pot three-component reaction between aldehyde, amino pyrazole, and 1,3-cyclohexanedione by using recyclable polyethylene glycol (PEG)-400 as a reaction medium. Utilizing this protocol a variety of pyrazolo[3,4-b]quinoline derivatives were synthesized in excellent yields.

Development and a Practical Synthesis of the JAK2 Inhibitor LY2784544

The route selection and process research and development of a practical synthesis for JAK2 inhibitor LY2784544 is described. The first-generation synthesis route, similar to that used in discovery for derivatization of a benzylic amine moiety, was 14 overall steps and possessed several steps that required extensive development for large-scale production. Route selection considerations led to a modified synthesis that utilized a novel vanadium-catalyzed carbon–carbon bond-forming arylation reaction for incorporation of the key benzylic morpholine moiety. A protecting group used to mask an amino pyrazole unit was modified from PMB to tert-butyl, resulting in a dramatic reduction in the overall length of the route. These two major changes resulted in an eight-step synthesis, which was six steps shorter than the first-generation synthesis. In the pilot plant, the new synthesis was scaled to produce >100 kg of LY2784544 in high yield and purity under GMP conditions. The overall development including the vanadi...

New Biologically Active N-(Tetrahydrobenzothienopyrimidin-4-YL)-Amino Acids, Thiourethane, Sulfonamides and Related Compounds

Some derivatives of thieno[2,3-d]pyrimidine containing amino acids 3a-i, imidazoles 4a-f, isothiocyanate 5, thiourethane 6, triazine 8, pyrimidine 10, sulphonamides 13a-d, 14, pyrazole 16 and pyrazolone 17 were synthesized. The structural assignments of the new compounds were based on analytical, spectroscopic measurements and chemical reactions. Some of the obtained compounds showed interesting antimicrobial activities.

Quantum mechanical calculations of amino pyrazole derivatives as corrosion inhibitors for zinc, copper and ?-brass in acid chloride solution

Quantum mechanical calculations have been applied to a series of pyrazole derivatives used as corrosion inhibitors for zinc, copper and α-brass in order to assess quantum chemistry as a means of evaluating effectiveness of corrosion inhibitors. The corresponding structures have been optimized and the energies and coefficients of their molecular orbitals (HOMO and LUMO) have been computed using the semi-empirical method, MNDO. The theoretical results are then compared with experimental data.