- Regioselective 1,3-dipolar cycloaddition of nitriles with nitrile imines generated from tetrazoles
-
A synthesis of 3,5-disubstituted-1,2,4-triazoles from nitriles and 5-aryltetrazoles is reported. When 5-aryltetrazoles are triflylated in the presence of nitriles, the resulting 5-aryl-2-triflyltetrazoles thermally generate N-triflyl-nitrile imines through a sequence of ring-chain tautomerization and denitrogenation. The N-triflyl-nitrile imines immediately undergo 1,3-dipolar cycloaddition with nitriles in a regioselective manner, forming the corresponding 1,2,4-triazoles.
- Miura, Tomoya,Hagiwara, Kohei,Nakamuro, Takayuki,Nagata, Yuuya,Oku, Naoki,Murakami, Masahiro
-
supporting information
p. 131 - 135
(2021/01/15)
-
- TfOH mediated intermolecular electrocyclization for the synthesis of pyrazolines and its application in alkaloid synthesis
-
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
-
p. 30071 - 30075
(2018/09/11)
-
- An eco-friendly synthesis of 2-pyrazoline derivatives catalysed by CeCl 3· 7 H 2O
-
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.].
- Bhat, Prabhat,Shridhar, Gomathi,Ladage, Savita,Ravishankar, Lakshmy
-
p. 1441 - 1448
(2017/09/25)
-
- Catalytic Synthesis of Chalcones and Pyrazolines Using Nanorod Vanadatesulfuric Acid: An Efficient and Reusable Catalyst
-
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
-
-
- A novel methodology for synthesis of dihydropyrazole derivatives as potential anticancer agents
-
A novel, simple, and efficient method for the synthesis of 4,5-dihydropyrazole derivatives has been developed. The reaction proceeded through the base-induced isomerization of easily accessible propargyl alcohols followed by cyclization of α,β-unsaturated hydrazones. Furthermore, selected compounds 3ab and 3ac exhibited good activities against Bel-7404 (human hepatoma cancer), HepG2 (human liver cancer), NCI-H460 (human lung cancer) and SKOV3 (human ovarian cancer) cell lines with IC50 in the range of 22-46 μmol L-1.
- Wang, Xu,Pan, Ying-Ming,Huang, Xiao-Chao,Mao, Zhong-Yuan,Wang, Heng-Shan
-
supporting information
p. 2028 - 2032
(2014/03/21)
-
- 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
-
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
-
p. 582 - 588
(2012/01/06)
-
- Thiocyanation on n-benzene rings of 1,3,5-trisubstituted pyrazolines with oxone
-
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
-
experimental part
p. 129 - 134
(2010/03/24)
-
- Synthesis of pyrazoline and isoxazoline in triethanolamine medium
-
Reactions of chalcones 1a-u with phenylhydrazine and hydrazine hydrate give pyrazolines 2a-u and with hydroxylamine hydrochloride yield isoxazolines 3a-c in triethanolamine medium. The structures of products are established by melting points, chemical studies and spectral data (IR and 1HNMR).
- Agrawal, Nitin N.,Soni
-
p. 2700 - 2701
(2007/10/03)
-
- REACTION OF SINGLET OXYGEN WITH 2-PYRAZOLINE: IMPLICATION FOR CATION RADICAL - SUPEROXIDE ION PAIR INTERMEDIATE
-
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
-
p. 3807 - 3812
(2007/10/02)
-