- TfOH mediated intermolecular electrocyclization for the synthesis of pyrazolines and its application in alkaloid synthesis
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TfOH mediated easy access to interesting pyrazolines starting from an aldehyde, phenylhydrazine and styrene has been developed. The scope of this synthetic methodology has been explored by synthesizing various 1,3,5-trisubstituted pyrazolines in very good yields with very high regioselectivity. The origin of regioselectivity has been explained by comparing the stability of possible intermediate carbocations. The synthetic utility of a green solvent has been explored by synthesizing some of pyrazolines in a DES medium. The synthetic application of the present methodology is employed in the synthesis of a pyrazoline alkaloid.
- Annes, Sesuraj Babiola,Vairaprakash, Pothiappan,Ramesh, Subburethinam
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- A modified and convenient method for the preparation of N-phenylpyrazoline derivatives
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Ten new N-phenylpyrazoline derivatives have been synthesized in high yields by condensation of chalcones with phenylhydrazine in the presence of potassium carbonate in reflux conditions. The workup is simple and involves treatment with ice-cold water. As compared with the previous method a considerable increase in the reaction rate with better yields has been observed.
- Safaei-Ghomi,Bamoniri,Soltanian-Telkabadi
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- Synthesis of 1, 3, 5-trisubstituted-4,5-dihydro-1H-pyrazole catalyzed by vitamin B1 and its fluorescence properties
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Abstract: An efficient synthesis of 1,3,5-trisubstituted-1H-pyrazoles was developed via cyclocondensation in 78–92% yields starting from α,β-unsaturated aldehydes/ketones with substituted phenylhydrazine using vitamin B1 as a catalyst, and was
- Zhang, Dawei,Ren, Lu,Liu, Ailing,Zhang, Yumin,Lv, Yang,Gu, Qiang
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p. 983 - 1001
(2022/02/09)
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- TBHP/Cu(OAc)2 mediated oxidation of pyrazolines: A convenient method for the preparation of pyrazoles
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An efficient and simple oxidative protocol has been developed for the preparation of pyrazoles from pyrazolines mediated by TBHP/Cu(OAc)2 at room temperature. The present protocol has been successfully applied for the preparation of various pyrazole compounds from heterocyclic pyrazolines.
- Kolla, Sai Teja,Somanaboina, Ramya,Bhimapaka, China Raju
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supporting information
p. 1425 - 1432
(2021/02/27)
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- Spectroscopic studies of aryl substituted 1-phenyl-2-pyrazolines: Steric and electronic substitution effects
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A series of aryl substituted 1-phenyl-2-pyrazolines containing electron-donating and electron-withdrawing substituents on different positions of the C3– or C5-aryl groups were synthesized and their steric and electronic effects on ch
- Soltani, Marzieh,Memarian, Hamid R.,Sabzyan, Hassan
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p. 903 - 917
(2018/09/18)
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- Microwave-irradiated synthesis and biological evaluation of 3,5-diaryl-1-phenyl-2-pyrazolines as antibacterial and anti-inflammatory agents
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In a wide search program towards a biologically active antibacterial and anti-inflammatory agents, a series of 3,5-diaryl-1-phenyl-2-pyrazoline have been synthesized with excellent yields employing microwave techniques starting from substituted α,β-unsaturated carbonyl compounds which undergo cyclization reactions with phenylhydrazine. The structures of newly synthesized compounds were characterized and confirmed on the basis of FT-IR, 1H NMR and mass spectral analyses. The synthesized compounds 3,5-diaryl-1-phenyl-2-pyrazolines had shown significant activity against Staphylococcus aureus (MTCC 87), Escherichia coli (MTCC 40), Pseudomonas aeruginosa (MTCC 424) and Proteus vulgaris (MTCC 426) by cup plate method using tetracycline-SD 037 as a reference standard. The anti-inflammatory property of 1,3,5-diaryl-1-phenyl-2-pyrazolines were screened by using carragenan induced paw edema method in Wistar rat. The anti-inflammatory activities were comparable to that of the standard drug diclofenac. The safety of 3,5-diaryl-1-phenyl-2-pyrazolines were reflected by toxicity studies.
- Kumar, Anjan,Rout, Sradhasini,Panda, Jnyanaranjan,Sahoo, Biswa Mohan,Banik, Bimal Krishna
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p. 1321 - 1326
(2020/06/27)
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- 13C NMR spectroscopy of heterocycles: 1-phenyl-3-aryl/t-butyl-5-arylpyrazoles
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A series of chalcones 1-12 were converted to pyrazolines (1Pi-12Pi) by reaction with phenylhydrazine followed by DDQ oxidation to produce the corresponding pyrazoles (1Pz-12Pz). Three 1-phenyl-3-t-butyl-5-arylpyrazoles (13Pz-15Pz) were synthesized using an analogous approach. Molecular modeling studies predicted the 5-aryl group of the pyrazoles for both series to have a torsion angle of 52°-54° whereas the 1-phenyl group was predicted to have 35°-37° torsion angles. The 3-aryl group was predicted to be essentially coplanar (-3°) with the pyrazole system in the first series. 13C NMR data for both series, 1Pz-12Pz and 13Pz-15Pz, were collected in DMSO-d6 at 50°C. A plot of the C4 chemical shifts for 1Pz-12Pz versus Hammet constants for 5-aryl substituents yielded a very good linear correlation (R2=0.96) with a slope of 1.5. The chemical shift data for C4 showed little or no dependence on 3-aryl substituents. The result for 13Pz-15Pz, despite only three points, was consistent with the first series results and yielded a ρ value of 2.0. Distal transmission of substituent effects (5-aryl groups) to C4 of the pyrazole system was reduced by roughly 50-60% of that of the analogous planar isoxazole system, but are not consistent with results for the similarly twisted 4-bromoisoxazoles.
- Hockstedler, Amy N.,Edjah, Beatrice A.,Azhar, Saajid Z.,Mendoza, Hadrian,Brown, Nicole A.,Arrowood, Hayley B.,Clay, Andrew C.,Shah, Anand B.,Duffek, Glenda M.,Cui, Jianmei,Baumstark, Alfons L.
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p. 125 - 131
(2017/04/14)
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- Catalytic Synthesis of Chalcones and Pyrazolines Using Nanorod Vanadatesulfuric Acid: An Efficient and Reusable Catalyst
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Nanorod vanadatesulfuric acid (VSA NRs), as a recyclable and ecologically benign catalyst, was used for the one-pot synthesis of chalcones and 1,3,5-triaryl-2-pyrazolines (TAPs). Chalcones were prepared via the condensation of substituted acetophenones with aryl-aldehydes under solvent-free conditions. Subsequently, the synthesized chalcones were used for the catalytic synthesis of TAPs via two-component condensation with phenyl hydrazine in refluxing ethanol. VSA is easily prepared by a simple reaction of chlorosulfonic acid and sodium metavanadate of high purity. Compared to conventional procedures, the present protocol offers several advantages such as simplicity of the procedure, appropriate reaction times, high to excellent yields, easily work-up, recoverability, and reusability of the catalyst, and simple purification of the products.
- Nasr-Esfahani, Masoud,Daghaghale, Mona,Taei, Mahbube
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- Nanocasting, Template Synthesis, and Structural Studies on Cesium Salt of Phosphotungstic Acid for the Synthesis of Novel 1,3,5-Triaryl-pyrazoline Derivatives
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The elimination of the silica matrix of composites by HF occurred by a two-step reaction deposition of a Cs2.5H0.5PW12O40 (CsHPW) salt nanocrystal. We used 2D hexagonal SBA-15 silica as a template for the nanofabrication of CsHPW nanoparticles. Nanocast CsHPW materials are stable against leaching and colloidization in polar solvents. The catalytic performance of the nanocast CsHPW materials exceeded that of bulk Cs2.5H0.5PW12O40, which is the most active among the acidic HPW salts. A series of novel 1,3,5-triaryl-pyrazoline derivatives were synthesized by the reaction between chalcone and phenylhydrazine in high yield in the presence of CsHPW salt nanocrystals.
- Fazaeli, Razieh,Aliyan, Hamid,Tangestaninejad, Shahram,Mohammadi, Esmaeel,Bordbar, Maryam
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p. 237 - 246
(2016/04/19)
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- Nanocasting, template synthesis, and structural studies on cesium salt of phosphotungstic acid for the synthesis of novel 1,3,5-triaryl-pyrazoline derivatives
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The elimination of the silica matrix of composites by HF occurred by a two-step reaction deposition of a Cs2.5H0.5PW 12O40 (CsHPW) salt nanocrystal. We used 2D hexagonal SBA-15 silica as a template for the nanof
- Fazaeli, Razieh,Aliyan, Hamid,Tangestaninejad, Shahram,Mohammadi, Esmaeel,Bordbar, Maryam
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experimental part
p. 237 - 246
(2012/06/30)
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- A convenient and efficient protocol for the synthesis of 1,3,5-triaryl-2-pyrazolines in acetic acid under ultrasound irradiation
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1,3,5-Triaryl-2-pyrazolines were synthesized in acetic acid in high yields within 60-180 min under ultrasound irradiation at room temperature.
- Lin, Zhi-Ping,Li, Ji-Tai
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experimental part
p. 267 - 271
(2012/06/18)
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- Tungstophosphoric acid supported on highly organosoluble polyamide (PW 12/PA): Highly efficient catalysts for the synthesis of novel 1,3,5-triaryl-2-pyrazoline derivatives
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A novel compound constructed from polyoxometalate (H3PW 12O40, PW12) and poly(amidoamine) (PA) was prepared at room temperature in an aqueous solution by an impregnation method. A series of novel 1,3,5-triaryl-2-pyrazoline derivatives was synthesized by the reaction between chalcone and phenylhydrazine in the presence of the title compound, PW12/PA, in high yields. The structures of the compounds obtained were determined by IR and 1H NMR spectra.
- Fazaeli, Razieh,Aliyan, Hamid,Mallakpour, Shadpour,Rafiee, Zahra,Bordbar, Maryam
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p. 582 - 588
(2012/01/06)
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- Thiocyanation on n-benzene rings of 1,3,5-trisubstituted pyrazolines with oxone
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An efficient aromatic thiocyanation of 1,3,5-trisubstituted pyrazolines occurred regioselectively at the para position of N-benzene rings using ammonium thiocyanate as a thiocyanation reagent and oxone as an oxidant.
- Wu, Guaili,Liang, Ruirui,Chen, Yongjiang,Wu, Longmin
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experimental part
p. 129 - 134
(2010/03/24)
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- Mechanically activated synthesis of 1,3,5-triaryl-2-pyrazolines by high speed ball milling
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An efficient mechanically activated solvent-free synthesis of 1,3,5-triaryl-2-pyrazolines from chalcones and phenylhydrazines using high speed ball milling is described. This method has notable advantages in terms of good yield, short reaction time and ne
- Zhu, Xingyi,Li, Zhenhua,Jin, Can,Xu, Li,Wu, Qianqian,Su, Weike
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experimental part
p. 163 - 165
(2010/04/22)
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- Synthesis and reactions of 4-[3-oxo-1-phenyl-3-(p-substituted phenyl)-propyl]-1-4-chloro-phenyl-2-(3-methyl-5-oxo-2-pyrazolin-1-yl) thiazole
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Compounds 4-[3-oxo-1-phenyl-3-(p-chloro or p-methoxyphenyl)-propyl]-1-[4-chlorophenyl)-2-(3-methyl-5-oxo-2-pyrazolin-1-yl)] -thiazole (II a-b) have been prepared. The reactions of compounds (II a-b) with hydrazines in ethanol and in acetic acid, hydroxylamine hydrochloride, aromatic aldehydes, zinc dust, Grignard reagents, P2S5 and polyphosphoric acid have been investigated.
- Hamad,Said,Amer,Yassin,El-Gendy
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- REACTION OF SINGLET OXYGEN WITH 2-PYRAZOLINE: IMPLICATION FOR CATION RADICAL - SUPEROXIDE ION PAIR INTERMEDIATE
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Kinetic studies on photosensitized oxygenation of 1,3,5-triaryl-2-pyrazolines show that an electron-transfer from the pyrazoline to singlet oxygen may take place to give a cation radical and superoxide ion pair.The reaction of pyrazoline cation radicals with superoxide ion shows the same product distribution with singlet oxygenation.
- Akasaka, Takeshi,Nakagawa, Masaru,Nomura, Yuko,Sato, Rikiya,Someno, Kazuo,Ando, Wataru
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p. 3807 - 3812
(2007/10/02)
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