3-substituted Pyrazoles Research Articles

Facile synthesis of 3-(pyrazol-1-yl) succinimides from Ag2CO3 -catalyzed aza-Michael addition of pyrazoles to maleimides

Herein, an effective and facile synthesis of 3-(pyrazol-1-yl) succinimides is first presented through silver-catalyzed aza-Michael addition of pyrazoles to maleimides. In the presence of 5 mol% of Ag2CO3, various pyrazoles smoothly reacted with maleimides in dichloroethane at 100 °C, to generate 3-(pyrazol-1-yl) succinimides in excellent yields. Notably, 3-substituted asymmetric pyrazoles exclusively give 3-pyrazolyl succinimides in excellent yields possibly due to the steric bulk of the 3-substituent excluding the formation of addition products of N 2. The method can also extend to gram scale.

Structure–activity relationship studies of 3-substituted pyrazoles as novel allosteric inhibitors of MALT1 protease

We report the discovery of a novel series of 1,5-bisphenylpyrazoles as potent MALT1 inhibitors. Structure–activity relationship exploration of a hit compound led to a potent MALT1 inhibitor. Compound 33 showed strong activity against MALT1 (IC50: 0.49 μM), potent cellular activity (NF-κB inhibition and inhibition of IL2 production), and high selectivity against caspase-3, -8, and -9. The results of a kinetics study suggest that compound 33 is a non-competitive inhibitor of MALT1 protein.

A Novel Synthesis, Characterization and Biological Studies of Ferrocenyl Substituted Pyrazoles

It has been discovered that ferrocenyl substituted heterocyclic compounds have wide scope of restorative methodology. The combination of ferrocenyl substituted pyrazole is the new class in these compounds with upgraded natural activity. This work center around blend of ferrocenyl substituted pyrazoles through novel course. The combination of 1-phenyl-3-ferrocenyl-pyrazole was examined including addition-cyclocondensation like response conditions. The response continued through three phases using of expansion cyclo-buildup of acetyl ferrocene with phenyl hydrazine pursued by cyclizing reagent iodine with NaHCO3. In both syntheses, each time single product isolated having good yields (87 and 79 %). Ferrocenyl substituted pyrazoles were examined by spectroscopic techniques (1H NMR, IR, MS) and their biological properties have been screened.

Magnesium-Catalyzed N2-Regioselective Alkylation of 3-Substituted Pyrazoles

A highly regioselective Mg-catalyzed alkylation of 3-substituted pyrazoles has been developed to provide N2-alkylated regioisomers. Using α-bromoacetates and acetamides as alkylating agents, this new method was applied to a variety of 3-substituted and 3,4-disubstituted pyrazoles to produce the N2-alkylated products with high regioselectivities ranging from 76:24 to 99:1 and 44–90% yields.

Microwave Irradiative Synthesis of Triazine Substituted Pyrazoles and Study of Antitubercular and Antimicrobial Activities

Microwave irradiative synthesis of triazine substituted pyrazoles i.e. (4-benzylideneamino-6-methyl-[1,3,5]-triazin-2-yl)-(5-methyl-2-substituted benzoyl/isonicotinoyl/cinnamoyl-pyrazol-3-yl)-amines have been achieved by the cyclocondensation of N-(4-benzylideneamino-6-methyl-[1,3,5]-triazin-2-yl)-3-oxo butyramide with substituted acid hydrazides. Synthesis of required butyramide was done by reacting 2,4-diamino-6-methyl-[1,3,5]-triazine with benzaldehyde and then condensing the product with ethyl acetoacetate. Structural investigation of synthesized compounds has been done by chemical transformation, elemental analysis and IR, 1H NMR, mass spectral studies. Study of antitubercular and antimicrobial activity of title compounds against some selected Gram-positive and Gram-negative microorganisms was performed to establish the relationship between structure and activity of compound.

Regioselective Synthesis, NMR, and Crystallographic Analysis of N1-Substituted Pyrazoles.

A systematic study of the N-substitution reactions of 3-substituted pyrazoles under basic conditions has been undertaken. Regioselective N1-alkylation, -arylation, and -heteroarylation of 3-substituted pyrazoles have been achieved using K2CO3-DMSO. The regioselectivity is justified by the DFT calculations at the B3LYP/6-31G**(d) level. A consistent steric effect on chemical shift has been observed for N-alkyl pyrazole analogues. Twenty-five X-ray crystallographic structures have been obtained to confirm the regiochemistry of the major products.

ChemInform Abstract: Oxone‐Mediated Facile Access to Substituted Pyrazoles.

AbstractStarting from easily accessible hydrazones, aryl‐ and alkyl‐ substituted pyrazoles are prepared.

3-Substituted pyrazoles and 4-substituted triazoles as inhibitors of human 15-lipoxygenase-1.

Investigation of 1N-substituted pyrazole-3-carboxanilides as 15-lipoxygenase-1 (15-LOX-1) inhibitors demonstrated that the 1N-substituent was not essential for activity or selectivity. Additional halogen substituents on the pyrazole ring, however, increased activity. Further development led to triazole-4-carboxanilides and 2-(3-pyrazolyl) benzoxazoles, which are potent and selective 15-LOX-1 inhibitors.

ChemInform Abstract: Synthesis and Antimicrobial Activity of Novel Thiazole Substituted Pyrazole Derivatives.

ChemInformVolume 44, Issue 45 Heterocyclic Compounds ChemInform Abstract: Synthesis and Antimicrobial Activity of Novel Thiazole Substituted Pyrazole Derivatives. Nitin D. Gaikwad, Nitin D. Gaikwad Dep. Chem., HPT Arts RYK Sci. Coll., Nasik 422 005, IndiaSearch for more papers by this authorSachin V. Patil, Sachin V. Patil Dep. Chem., HPT Arts RYK Sci. Coll., Nasik 422 005, IndiaSearch for more papers by this authorVivek D. Bobade, Vivek D. Bobade Dep. Chem., HPT Arts RYK Sci. Coll., Nasik 422 005, IndiaSearch for more papers by this author Nitin D. Gaikwad, Nitin D. Gaikwad Dep. Chem., HPT Arts RYK Sci. Coll., Nasik 422 005, IndiaSearch for more papers by this authorSachin V. Patil, Sachin V. Patil Dep. Chem., HPT Arts RYK Sci. Coll., Nasik 422 005, IndiaSearch for more papers by this authorVivek D. Bobade, Vivek D. Bobade Dep. Chem., HPT Arts RYK Sci. Coll., Nasik 422 005, IndiaSearch for more papers by this author First published: 14 October 2013 https://doi.org/10.1002/chin.201345125Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume44, Issue45November 5, 2013 RelatedInformation

Synthesis of 3-Substituted Pyrazole Derivatives by Mixed Anhydride Method and Study of Their Antibacterial Activities

A convenient synthesis of 3-substituted pyrazole derivatives by a mixed anhydride method using i-butylchloroformate and N-methylmorpholine at −20 °C in tetrahydrofuran and study of in vitro antibacterial activities of the prepared compounds against Staphylococcus epidermidis, Bacillus subtilis, Pseudomonas aeruginosa, and Proteus valguris by agar-diffusion method were carried out. The results suggested that the products 4a, 4b, and 4c exhibited moderate to feeble inhibition against all test bacteria at greater concentration but 4d was best against Staphylococcus epidermidis (22 mm) and worst against Pseudomonas aeruginosa (16 mm) at the greatest concentration (2.5 mg/ml), and the activities decreased with decrease in concentration. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]

ChemInform Abstract: Advances in the Bestmann—Ohira Reagent‐Assisted Regioselective Synthesis of Substituted Pyrazoles, Triazoles, and Oxazoles

AbstractReview: 40 refs.

Synthesis and Antimicrobial Activity of Novel Thiazole Substituted Pyrazole Derivatives

A series of new 1-[4-(2,3,4-substituted-phenyl) thiazol-2-yl]-3-(2,3,4-substituted-phenyl)-1H-pyrazole-4-carbaldehyde (4a, 4b, 4c, 4d, 4e, 4f, 4g, 4h, 4i, 4j, 4k, 4l, 4m), 4-[4-(4-substituted-phenyl) thiazol-2-yl]-3-(4-substituted-phenyl)-1-phenyl-1H-pyrazole (7a, 7b, 7c, 7d, 7e, 7f, 7g, 7h, 7i), 4-[4-(4-substituted phenyl)thiazol-2-yl]-1-phenyl-1H-pyrazol-3-amine (10a, 10b, 10c, 10d, 10e, 10f, 10g) have been synthesized by using Vilsmeier Haack formylation and Hantzsch reaction in high yield. All the synthesized compounds were tested qualitative (Zone of inhibition) and quantitative antimicrobial activities (MIC). Most of the synthesized compounds showed potent antimicrobial activity against gram positive and gram negative bacteria as well as fungi species.

Multicomponent Assembly of Anionic and Neutral Decanuclear Copper(II) Phosphonate Cages

A multicomponent synthetic strategy involving copper(II) ions, tert-butylphosphonic acid (t-BuPO(3)H(2)) and 3-substituted pyrazole ligands has been adopted for the synthesis of soluble molecular copper(II) phosphonates. The use of six different 3-substituted pyrazoles, 3-R-PzH [R = H, Me, CF(3), Ph, 2-pyridyl (2-Py), and 2-methoxyphenyl (2-MeO-C(6)H(4))] as ancillary ligands afforded nine different decanuclear cages, [Cu(5)(μ(3)-OH)(2)(O(3)P-t-Bu)(3)(3-R-Pz)(2)(X)(2)](2)·(Y) where R = H, X = t-BuPO(3)H, and Y = (Et(3)NH(+))(4)(solvent) (1); R = Me, X = 3-MePzH, and Y = solvent (2); R = Me, X = t-BuPO(3)H, and Y = (Et(3)NH(+))(4)(solvent) (3); R = CF(3), X = t-BuPO(3)H, and Y = (Et(3)NH(+))(4)(solvent) (4); R = Ph, X = 3-PhPzH, and Y = solvent (5); R = 2-Py, X = 0.5 MeOH, and Y = solvent (6); R = 2-Py, X = none, and Y = solvent (7); R = 2-Py, X = H(2)O, and Y = (Et(3)NH(+)·PF(6)(-))(2)(solvent) (8); R = 2-MeO-C(6)H(4), X = MeOH or 0.5:0.5 MeOH/H(2)O, and Y = solvent (9). Compounds 1-6, 8, and 9 were isolated using a direct synthetic method which involves the reaction of copper(II) salts and the ligands, while 7 was obtained from an indirect route involving the reaction of preformed copper-pyridylpyrazolate precursor complexes and t-BuPO(3)H(2). The decametallic compounds 1-9 possess a butterfly shaped core. The core of the cages 1, 3, and 4 are tetraanionic and contain more phosphonates than pyrazole ligands, while the other cages are neutral and contain more pyrazoles than phosphonate ligands. Compounds 1-6 have been studied by electrospray ionization-high-resolution mass spectrometry (ESI-HRMS). The decanuclear cage 6 was shown to be a good plasmid modifier.

ChemInform Abstract: Regioselective Multicomponent Synthesis of Fully Substituted Pyrazoles and Bispyrazoles Catalyzed by Zinc Triflate.

AbstractThe optimized conditions A) or B) render possible the reaction of aldehydes, aryl hydrazines and ester (III) to give high yields of the target compounds.

A convenient approach to β-heteroarylated (C–N bond) ketones from Cs2CO3 promoted reaction between propargyl alcohols and nitrogen-heterocycles

An efficient and direct approach to β-heteroarylated (C-N bond) ketones is demonstrated. Base promoted redox isomerization of propargyl alcohol to α,β-unsaturated ketone followed by conjugate addition to NH-heteroarenes affords a wide range of β-heteroarylated ketones in good to excellent yields. Aryl, heteroaryl, alkyl C(sp), and terminal alkynes containing unactivated propargyl alcohols effectively undergo redox-isomerization conjugate addition (RICA) with NH-heteroarenes. Reaction of 3-substituted pyrazoles or indazole with propargyl alcohols enables highly regioselective products. A diverse range of NH-bearing nucleophiles such as: pyrazoles, imidazole, triazoles, pyrrole, indoles and aniline participate in this reaction and deliver the corresponding β-heteroarylated ketones.

3-Substituted Pyrazole Analogs of the Cannabinoid Type 1 (CB1) Receptor Antagonist Rimonabant: Cannabinoid Agonist-Like Effects in Mice via Non-CB1, Non-CB2 Mechanism

The prototypic cannabinoid type 1 (CB₁) receptor antagonist/inverse agonist, rimonabant, is comprised of a pyrazole core surrounded by a carboxyamide with terminal piperidine group (3-substituent), a 2,4-dichlorophenyl group (1-substituent), a 4-chlorophenyl group (5-substituent), and a methyl group (4-substituent). Previous structure-activity relationship (SAR) analysis has suggested that the 3-position may be involved in receptor recognition and agonist activity. The goal of the present study was to develop CB₁-selective compounds and explore further the SAR of 3-substitution on the rimonabant template. 3-Substituted analogs with benzyl and alkyl amino, dihydrooxazole, and oxazole moieties were synthesized and evaluated in vitro and in vivo. Several notable patterns emerged. First, most of the analogs exhibited CB₁ selectivity, with many lacking affinity for the CB₂ receptor. Affinity tended to be better when [³H]5-(4-chlorophenyl)-1-(2,4-dichloro-phenyl)-4-methyl-N-(piperidin-1-yl)-1H-pyrazole-3-carboxamide (SR141716), rather than [³H](-)-cis-3-[2-hydroxy-4(1,1-dimethyl-heptyl)phenyl]-trans-4-(3-hydroxy-propyl)cyclohexanol (CP55,940), was used as the binding radioligand. Second, many of the analogs produced an agonist-like profile of effects in mice (i.e., suppression of activity, antinociception, hypothermia, and immobility); however, their potencies were not well correlated with their CB₁ binding affinities. Further assessment of selected analogs showed that none were effective antagonists of the effects of Δ⁹-tetrahydrocannabinol in mice, their agonist-like effects were not blocked by rimonabant, they were active in vivo in CB₁⁻/⁻ mice, and they failed to stimulate guanosine-5'-O-(3-[³⁵S]thio)-triphosphate binding. Several analogs were inverse agonists in the latter assay. Together, these results suggest that this series of 3-substituted pyrazole analogs represent a novel class of CB₁-selective cannabinoids that produce agonist-like effects in mice through a non-CB₁, non-CB₂ mechanism.

Pd-catalyzed Negishi coupling of pyrazole triflates with alkyl zinc halides

A mild, functional group tolerant palladium-catalyzed Negishi coupling of pyrazole triflates and nonaflates with alkyl, benzyl, and aryl zinc halides has been developed. It allows quick access to 3-substituted pyrazole analogs at late stage via common synthetic intermediates.

Synthesis, characterization and in vitro cytotoxic properties of some new Schiff and Mannich bases in Hep G2 cells

A series of 5-substituted-4-amino-3-mercapto-1,2,4-triazoles were synthesized and were treated with various 3-substituted pyrazole aldehydes to obtain a series of new Schiff bases (3a–l). Few of the selected Schiff bases were converted into Mannich bases by reaction with diphenylamine/morpholine in presence of formaldehyde in ethanol media (4a–e, 5a–e). These newly synthesized compounds were characterized by elemental analysis, IR, NMR and mass spectrometry studies. A comparative study on the cytotoxic activities of few selected Schiff and Mannich bases was done in HepG2 cells using MTT assay. Few of the screened Schiff bases, 3a, 3d, 3e, 3g and 3h showed dose dependent cytotoxic activity, 3a being the most potent with an IC50 value of 0.018 g/l comparable to the standard drug doxorubicin. Among the Mannich bases, 5b was the most active with an IC50 value of 0.034 g/l. The Schiff bases were found to be more active, when compared to Mannich bases derived from them. The morpholine derived Mannich bases were more potent than those obtained from diphenyl amine.

Synthesis of some novel heterocyclic dyes derived from pyrazole derivatives

Diazotized aryl amines were coupled with 3-substituted 5-amino pyrazoles to produce a series of novel 3-substituted 5-amino-4-arylazopyrazoles. Also, 3-substituted 5-amino-pyrazoles were diazotized and coupled with different phenols to give the corresponding novel 3-substituted 5-aryl azo pyrazoles. These dyes were characterized by elemental analysis and spectral data, applied to different types of fibres (wool, polyester and a blend of wool/polyester as disperse dyes) and their fastness properties were evaluated.

Synthesis of Quinolone Substituted Pyrazoles, Isoxazoles and Pyridines as a Potential Blue Luminophors

Series of quinolone C(3)-substituted pyrazolines, isoxazolines, pyridines and pyrimidines were synthesized in good yields by the cyclocondensation reactions of 1, 2-unsaturated ketones and hydrazines, hydroxylamine hydrochloride and dimedone respectively. The quinolone derivatives (3, 5 and 7) were synthesized and further studied for their photophysical properties. High absorption and quantum yield are found for N(1)-phenyl and C(3,4)-dimethoxy substituents on phenyl ring (3h). Energy optimization by PM6 methods showed high stability required for selection of suitable candidates to be use as future blue emitters.