1450-62-0Relevant academic research and scientific papers
Spectroscopic studies of aryl substituted 1-phenyl-2-pyrazolines: Steric and electronic substitution effects
Soltani, Marzieh,Memarian, Hamid R.,Sabzyan, Hassan
, p. 903 - 917 (2018/09/18)
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
TfOH mediated intermolecular electrocyclization for the synthesis of pyrazolines and its application in alkaloid synthesis
Annes, Sesuraj Babiola,Vairaprakash, Pothiappan,Ramesh, Subburethinam
, p. 30071 - 30075 (2018/09/11)
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.
13C NMR spectroscopy of heterocycles: 1-phenyl-3-aryl/t-butyl-5-arylpyrazoles
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.
, p. 125 - 131 (2017/04/14)
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.
Catalytic Synthesis of Chalcones and Pyrazolines Using Nanorod Vanadatesulfuric Acid: An Efficient and Reusable Catalyst
Nasr-Esfahani, Masoud,Daghaghale, Mona,Taei, Mahbube
, p. 17 - 24 (2017/01/17)
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.
An eco-friendly synthesis of 2-pyrazoline derivatives catalysed by CeCl 3· 7 H 2O
Bhat, Prabhat,Shridhar, Gomathi,Ladage, Savita,Ravishankar, Lakshmy
, p. 1441 - 1448 (2017/09/25)
Abstract: 1,3,5-triaryl-2-pyrazoline derivatives were synthesised by a condensation reaction between chalcones and phenyl hydrazine using cerium chloride heptahydrate as a catalyst. All these reactions were carried out in ethyl lactate (70%) as a green solvent. Easy and efficient work up, recyclability of solvent and catalyst are the key merits of this protocol. Graphical Abstract:: SYNOPSIS A facile protocol for the synthesis of 1,3,5-triaryl-2-pyrazolines is described. The solvent ethyl lactate, obtained from renewable sources, is biodegradable. The catalyst CeCl 3· 7 H 2O is a water-tolerant Lewis acid with low toxicity. Easy and clean work up, recyclable solvent and catalyst are merits of the protocol. The reaction works well for all systems giving good yields of the desired products.[Figure not available: see fulltext.].
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
Fazaeli, Razieh,Aliyan, Hamid,Mallakpour, Shadpour,Rafiee, Zahra,Bordbar, Maryam
experimental part, p. 582 - 588 (2012/01/06)
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.
Thiocyanation on n-benzene rings of 1,3,5-trisubstituted pyrazolines with oxone
Wu, Guaili,Liang, Ruirui,Chen, Yongjiang,Wu, Longmin
experimental part, p. 129 - 134 (2010/03/24)
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.
Mechanically activated synthesis of 1,3,5-triaryl-2-pyrazolines by high speed ball milling
Zhu, Xingyi,Li, Zhenhua,Jin, Can,Xu, Li,Wu, Qianqian,Su, Weike
experimental part, p. 163 - 165 (2010/04/22)
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
Novel synthesis of 1,3,5-trisubstituted 2-pyrazolines promoted by chlorotrimethylsilane
Xie, Zengyang,Bian, Xiaoqin,Geng, Xin,Li, Shuangshuang,Wang, Cunde
, p. 52 - 54 (2008/09/19)
1,3,5-Trisubstituted-2-pyrazolines were effectively synthesised by utilising chlorotrimethylsilane as an efficient promoter in the cyclisation addition of Phenylhydrazine to chalcones under nitrogen in acetonitrile. The clean, mild reaction conditions, high yields and a simple workup of target compounds were attractive features of the reaction which enables a facile preparative procedure for building the pyrazoline ring.
Convenient synthesis of highly functionalized pyrazolines via mild, photoactivated 1,3-dipolar cycloaddition
Wang, Yizhong,Rivera Vera, Claudia I.,Lin, Qing
, p. 4155 - 4158 (2008/02/12)
A mild, photoactivated 1,3-dipolar cycloaddition procedure was successfully developed for the synthesis of polysubstituted pyrazolines. This procedure involved the in situ generation of the reactive nitrile imine dipoles using a hand-held UV lamp at 302 n
