Pyrazole derivatives
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Published data on the methods of preparation of pyrazolopyrazoles are summarized and described systematically. The title compounds are subdivided according to the position of fusion between the 2 pyrazole rings. In addition, pyrazolo[3,4-c]pyrazoles are useful for the treatment of esophageal and gastrointestinal mucosa injury9 and brain injury, 10 and also as immunostimulatory, 11 antianginal, 12 and antitumor13 agents. A review covering the literature data on the synthesis of compounds with 2 or more pyrazole rings linked to each other published before 1995 appeared in 1995.
35p langthannam 29-12-2021 10 0 Download
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This review article represents a survey covering the synthetic strategies leading to 5-membered heterocycles. The reactions are subdivided into groups that cover the synthetic methods of those heterocycles, i.e. pyrroles, furans, thiophenes, pyrazoles, isoxazoles, thiazoles, and others, utilizing benzoylacetonitriles as starting precursor from 1985 up to the present. The reactions are subdivided into groups that cover the synthetic methods for those heterocycles from benzoylacetonitriles.
27p langthannam 29-12-2021 8 0 Download
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3-Substituted-1-phenyl-1H -pyrazolo[3,4-d]pyrimidin-4-amines 2a–c were synthesized by treating 5-aminopyrazole-4-carbonitriles 1a–c with formamide. The reactivity of compounds 1a–c towards some cyclic anhydrides was studied. The condensation of 5-aminopyrazole-4-carbonitrile 1b with triethylorthoformate gives imidate 7b, which reacts with a series of primary amines and leads to pyrazolo[3,4-d]pyrimidine-4-amines 9 and 10. The reaction of imidate 7b with ammonia and hydroxylamine afforded pyrazolopyrimidine 2b and pyrazolo[3,4-d]pyrimidin-5-(4H)-ol 11, respectively.
12p langthannam 29-12-2021 13 0 Download
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A facile synthesis of a series of new 5-bromotropono[c]pyrazole derivatives (3 and 10–15) as well as 5- bromotropono[c]isoxazole (17) is described, involving a condensation reaction of 3-acetyl-5-bromotropolone (1) with hydrazine monohydrate (2), arylhydrazine hydrochlorides (4–9), and hydroxylamine hydrochloride (16), respectively. All the synthesized compounds were obtained in good yields of 56%–77% and their structures were characterized by spectral data and HRMS.
7p langthannam 29-12-2021 7 0 Download
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A new, less expensive, solvent-free procedure was developed for the synthesis of some new derivatives of various fused heterocyclic ring systems, namely azolopyridazine, azolotriazine, azinotriazine, thienopyridine, and pyrazolopyridine. The structures of the products prepared were established by their spectral data and elemental analyses. Eight compounds were evaluated for their in vitro antimicrobial activity. Some of the tested compounds exhibited moderate to significant antibacterial and antifungal activities.
15p langthannam 29-12-2021 10 0 Download
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A series of novel thiazoles and 1,3-thiazine derivatives were synthesized in good yield via reaction of ethyl 3-(1-(2-thiocarbamoylhydrazono)ethyl)-1,5-diphenyl-1H -pyrazole-4-carboxylate with hydrazonoyl halides and arylidenemalononitriles, respectively. The structure of the newly synthesized products was elucidated via elemental analysis, spectral data, and alternative routes whenever possible. Moreover, the antiviral screening of the products was evaluated and the results revealed that some of them have strong to moderate potency against the rabies virus compared with the reference drug.
13p langthannam 29-12-2021 6 0 Download
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The latter compounds react also by grinding method with nitrogen nucleophiles such as hydrazine hydrate, phenylhydrazine, and thiosemicarbazide to afford the corresponding pyrazol-3-yl pyrazolines. A series of 6-pyrazolylpyrimidine2-thione derivatives were prepared by reaction of the above chalcones with thiourea by grinding method in the presence of a catalytic amount of sodium hydroxide at room temperature. In addition, 7-pyrazolylpyridopyrimidine-3-thione was prepared by reaction of chalcone with 6-aminothiouracil.
15p langthannam 29-12-2021 6 0 Download
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A simple, synthesis of 2-(3-methyl-5-oxo-4, 5-dihydro-1h-pyrazol-1-yl) quinazolin-4(3H)-one 6(a-d) derivatives, an easy, clean, and economical methodology has been defined. The development of a new pathway for the preparation of substituted derivatives of Quinazoline Pyrazole is highlighted in this report. The mild, inexpensive polyphosphoric acid has proven to be an effective catalyst for excellent yields in the above multi-component reaction. Widely available and mostly benign catalyst and easy purification are among the several attractive features.
6p nguaconbaynhay11 16-04-2021 11 2 Download
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Usnic acid isolated from lichen was a potential bioactivity compound. It has a broad spectrum bioactivity, including antiviral, anti-inflammatory, anticancer… However, low solubility in water limited its application. Many researchs have done to overcome the restriction. Recent results showed that usnic acid derivatives bearing triazole, enamine, pyrazole and benzylidene groups had strong antiviral and anticancer activities. Thus, investigation of usnic acid derivatives synthesis was an attractive aspect due to the diversity of bioactivities of usnic acid derivatives.
8p larachdumlanat127 02-01-2021 5 1 Download
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Usnic acid isolated from lichen was a potential bioactivity compound. It has a broad spectrum bioactivity, including antiviral, anti-inflammatory, anticancer… However, low solubility in water limited its application. Many researchs have done to overcome the restriction. Recent results showed that usnic acid derivatives bearing triazole, enamine, pyrazole and benzylidene groups had strong antiviral and anticancer activities. Thus, investigation of usnic acid derivatives synthesis was an attractive aspect due to the diversity of bioactivities of usnic acid derivatives.
8p trinhthamhodang9 04-12-2020 14 1 Download
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There was an understanding between the benefits of restricting affinities and the data obtained from the practical anticancer screening of the tested compounds.
13p vijiraiya2711 27-05-2020 12 1 Download
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Design and synthesis of pyrazole-dimedone derivatives were described by one-pot multicomponent reaction as new antimicrobial agents. These new molecular framework were synthesized in high yields with a broad substrate scope under benign conditions mediated by diethylamine (NHEt2).
13p vijiraiya2711 27-05-2020 9 0 Download
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A novel series of substituted 2-thiohydantoin incorporated with benzoimidazole, pyrazole, triazole and/or benzoxa‑ zole moieties has been synthesized using (E)-3-[1-(4-bromophenyl)ethylideneamino]-2-thioxoimidazolidin-4-one 1 as the key starting material.
13p vijiraiya2711 27-05-2020 15 1 Download
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Pyrazolines show different biological activities. In recent years, interest in the chemistry of hydrazonoyl halides has been renewed. 1,3,4-Thiadiazoles are one of the most common heterocyclic pharmacophores with a wide range of biological activities.
18p vijiraiya2711 27-05-2020 9 0 Download
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Take-all of wheat, caused by the soil-borne fungus Gaeumannomyces graminis var. tritici, is one of the most important and widespread root diseases. Given that take-all is still hard to control, it is necessary to develop new effective agrochemicals.
6p vijiraiya2711 27-05-2020 15 1 Download
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The diacylhydrazine derivatives have attracted considerable attention in recently years due to their simple structure, low toxicity, and high insecticidal selectivity. As well as 3-bromo-1-(3-chloropyridin-2-yl)-1H-pyrazole is an important scaffold in many insecticidal molecules.
11p vijiraiya2711 27-05-2020 10 0 Download
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An ecofriendly methods for the synthesis of medicinally important class of heterocyclic scaffold, pyrazole 4-carbonitrile derivatives by one pot three component reaction of malononitrile, phenyl hydrazine and aromatic aldehyde has been achieved at room temperature.
8p tocectocec 25-05-2020 6 0 Download
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Pyrrolo[3,4-c]pyrazole-4,6(1H,5H)-dione, pyrano[2,3-c]pyrazole-5-carbonitrile, pyrano[2,3-d]4-imidazolines, pyrido[2,1-b]benzimidazole, pyrido[2,1-b][1,3]benzoxazole, pyrido[2,1- b][1,3]benzothiazole and pyrido[2,1-b]quinazoline were synthesised from antipyrine derivatives with appropriate reagents such as maleimides, malononitrile, ethyl cyanoacetate, benzimidazole-2-acetonitrile, benzothiazole-2-acetonitrile, benzoxazol-2-acetonitrile, benzoylacetonitrile and other reagents.
8p kethamoi1 20-11-2019 8 1 Download
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An efficient grinding protocol for the synthesis of dihydropyrano[2,3-c]pyrazole derivatives from acetylene ester, hydrazine hydrate, aryl aldehydes and malononitrile under solvent free conditions has been achieved with excellent yields. The structures of the synthesized compounds were deduced by spectroscopic techniques and the compounds were further evaluated for their in vitro antioxidant and antimicrobial activities.
11p trinhthamhodang1 16-11-2019 19 0 Download