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Thieme E-Books & E-Journals - Synthesis / Issue

AB - Hepatitis B virus (HBV) is an infectious disease, which can cause acute and chronic infections. Every year, over 7.5 million persons die due to HBV. No effective drug exists for the treatment of HBV. Thus, we designed and synthesized 16 new pyridine-pyrazole-sulfonate compounds containing pyridine-SCH2-pyrazole and pyridine-pyrazole derivatives. Their structures were characterized by 1H-NMR, 13C-NMR, IR, mass spectroscopy, and high performance liquid chromatography. All the compounds were evaluated for their anti-HBV activities and a structure-activity relationship (SAR) in HepG2 2.2.15 cells was established. We found that the pyridine-pyrazole derivatives could inhibit the HBV gene expression and viral DNA replication. Among these compounds, 2-[3-(2-nitrophenylsulfonyl)oxy-5-pyrazol-yl]pyridine 19d has shown the most potent inhibitory activity with an IC50 value of 9.19 μM and high selectivity index, SI (TC50/IC50) of 35.46. Hence, we believe our compounds could serve as a potential lead compounds for anti-HBV drug development.

1 [1–9] .Among heterocycles, pyrazole derivatives are an important class of nitrogen containing five membered heterocyclic compounds that have attracted much more attention in recent time due to their usefulness in the field of drug discovery and agricultural research [10–16] .

T1 - Synthesis of pyrazole derivatives, with biological activity in signal transduction therapy

Synthesis of Chromone-Related Pyrazole Compounds - …

AB - The titanium-catalyzed 3-component coupling of an alkyne, isonitrile, and amine can be used to generate tautomers of 1,3-diimines. These diimines produced in situ undergo cyclization with hydrazine and hydrazine derivatives in a one-pot procedure to provide pyrazoles. Seventeen examples of pyrazoles are provided using this one-pot, 4-component procedure from simple starting materials. The regioselectivity of the alkyne addition can be controlled in some cases with catalyst architecture, and regioselectivity of monosubsituted hydrazines to unsymmetrical 1,3-diimines is discussed. This multicomponent coupling strategy was applied to the synthesis of withasomnine in an efficient procedure, which gave the natural product in 24% overall yield from 4-pentyn-1-ol.

N2 - We describe the synthesis of the title gem-difluoropyrazole and hydrate derivative by reaction of 3,5-diphenylpyrazole with the NF reagent Selectfluor. In addition to spectral characterization of the two products, X-ray crystal structures were determined and an analysis of the charge densities of each compound was carried out. It is proposed that a weakened NN bond in the parent pyrazole, perhaps a result of the gem-difluoro substitution, promotes formation of the hydrate. The title gem-difluoropyrazole is a potential precursor to gem-difluorinated cyclopropanes.

Synthesis of Chromone-Related Pyrazole ..

AB - We describe the synthesis of the title gem-difluoropyrazole and hydrate derivative by reaction of 3,5-diphenylpyrazole with the NF reagent Selectfluor. In addition to spectral characterization of the two products, X-ray crystal structures were determined and an analysis of the charge densities of each compound was carried out. It is proposed that a weakened NN bond in the parent pyrazole, perhaps a result of the gem-difluoro substitution, promotes formation of the hydrate. The title gem-difluoropyrazole is a potential precursor to gem-difluorinated cyclopropanes.

A potent kinase inhibitor pyrazole derivative, 1,3-di-tert-butyl-N- (4fiuorophenyl)-1,6-dihydroimidazo[4,5-c]pyrazole-5-amine, has been found in Nested Chemical Library (NCL™) during a high throughput screening (HTS) kinase assay. Since the sample had only 91,3% purity, the biochemical assay was followed by the resynthesis of the hit molecule in a purity of 97%. The repeated biochemical assay showed that the purified substance is inactive. It was concluded that the biological activity should be attributed to one or more minor impurities. The mass spectrum of the original chemical sample showed two minor components. These imidazo[4,5-c]pyrazole-5-yl)-amine derivatives have been synthesized for hit validation purposes.

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Short Review on the Synthesis of Thiophene, Pyrazole, …


A Short Review on Pyrazole Derivatives and their Applications

N2 - The titanium-catalyzed 3-component coupling of an alkyne, isonitrile, and amine can be used to generate tautomers of 1,3-diimines. These diimines produced in situ undergo cyclization with hydrazine and hydrazine derivatives in a one-pot procedure to provide pyrazoles. Seventeen examples of pyrazoles are provided using this one-pot, 4-component procedure from simple starting materials. The regioselectivity of the alkyne addition can be controlled in some cases with catalyst architecture, and regioselectivity of monosubsituted hydrazines to unsymmetrical 1,3-diimines is discussed. This multicomponent coupling strategy was applied to the synthesis of withasomnine in an efficient procedure, which gave the natural product in 24% overall yield from 4-pentyn-1-ol.

com A Short Review on Pyrazole ..

N2 - A potent kinase inhibitor pyrazole derivative, 1,3-di-tert-butyl-N- (4fiuorophenyl)-1,6-dihydroimidazo[4,5-c]pyrazole-5-amine, has been found in Nested Chemical Library (NCL™) during a high throughput screening (HTS) kinase assay. Since the sample had only 91,3% purity, the biochemical assay was followed by the resynthesis of the hit molecule in a purity of 97%. The repeated biochemical assay showed that the purified substance is inactive. It was concluded that the biological activity should be attributed to one or more minor impurities. The mass spectrum of the original chemical sample showed two minor components. These imidazo[4,5-c]pyrazole-5-yl)-amine derivatives have been synthesized for hit validation purposes.

A novel pyrazole synthesis - Combinatorial Chemistry Review

The titanium-catalyzed 3-component coupling of an alkyne, isonitrile, and amine can be used to generate tautomers of 1,3-diimines. These diimines produced in situ undergo cyclization with hydrazine and hydrazine derivatives in a one-pot procedure to provide pyrazoles. Seventeen examples of pyrazoles are provided using this one-pot, 4-component procedure from simple starting materials. The regioselectivity of the alkyne addition can be controlled in some cases with catalyst architecture, and regioselectivity of monosubsituted hydrazines to unsymmetrical 1,3-diimines is discussed. This multicomponent coupling strategy was applied to the synthesis of withasomnine in an efficient procedure, which gave the natural product in 24% overall yield from 4-pentyn-1-ol.

Coordination chemistry of pyrazole ..

AB - A potent kinase inhibitor pyrazole derivative, 1,3-di-tert-butyl-N- (4fiuorophenyl)-1,6-dihydroimidazo[4,5-c]pyrazole-5-amine, has been found in Nested Chemical Library (NCL™) during a high throughput screening (HTS) kinase assay. Since the sample had only 91,3% purity, the biochemical assay was followed by the resynthesis of the hit molecule in a purity of 97%. The repeated biochemical assay showed that the purified substance is inactive. It was concluded that the biological activity should be attributed to one or more minor impurities. The mass spectrum of the original chemical sample showed two minor components. These imidazo[4,5-c]pyrazole-5-yl)-amine derivatives have been synthesized for hit validation purposes.

Coordination chemistry of pyrazole-derived ..

Heterocyclic compounds are acquiring more importance in recent years because of their pharmacological activities. Pyrazolones have a particular value due to their broad spectrum of biological activity and their wide ranging utility as synthetic tools in the design of various bioactive molecules. Pyrazolone is a five membered lactum ring, containing two nitrogen and one ketonic group in its structure. In addition, pyrazolones possess antimicrobial, antifungal, antimycobacterial, antibacterial, anti-inflammatory, antitumor, gastric secretion stimulatory, antidepressant and antifilarial activities. They also serve as precursors for dyes, pigments, pesticides and chelating agents, besides finding applications in the extraction and separation of various metal ions. The high therapeutic properties of the pyrazolone releted drugs have encouraged the medicinal chemists to synthesized a large number of novel chemotherapeutic agents. Numerous methods for the synthesis of pyrazolone and also their various structure reactions offer enormous scope in the field of medicinal chemistry. This articles aims to review the work reported, their chemistry and biological activities of pyrazolone during past years.

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