- Solventless synthesis of poly(pyrazolyl) phenyl-methane ligands and thermal transformation of tris(3,5-dimethylpyrazol-1-yl)phenylmethane
-
The solventless synthesis of tris(pyrazolyl)phenylmethane ligands of formula C6H5C(PzR2)3 (R = H, Me), starting from PhCCl3 and 3,5-dimethylpyrazole (PzMe2) or pyrazole (Pz) was performed.
- Rodríguez-Venegas, Edith,García-Báez, Efrén V.,Martínez-Martínez, Francisco J.,Cruz, Alejandro,Padilla-Martínez, Itzia I.
-
-
Read Online
- Iodonium salts as efficient iodine(iii)-based noncovalent organocatalysts for Knorr-type reactions
-
Hypervalent iodine(iii)-derivatives display higher catalytic activity than other aliphatic and aromatic iodine(i)- or bromine(i)-containing substrates for a Knorr-type reaction of N-acetyl hydrazides with acetyl acetone to give N-acyl pyrazoles. The highe
- Yunusova, Sevilya N.,Novikov, Alexander S.,Soldatova, Natalia S.,Vovk, Mikhail A.,Bolotin, Dmitrii S.
-
p. 4574 - 4583
(2021/02/03)
-
- Predicting the catalytic activity of azolium-based halogen bond donors: an experimentally-verified theoretical study
-
This report demonstrates the successful application of electrostatic surface potential distribution analysis for evaluating the relative catalytic activity of a series of azolium-based halogen bond donors. A strong correlation (R2> 0.97) was observed between the positive electrostatic potential of the σ-hole on the halogen atom and the Gibbs free energy of activation of the model reactions (i.e., halogen abstraction and carbonyl activation). The predictive ability of the applied approach was confirmed experimentally. It was also determined that the catalytic activity of azolium-based halogen bond donors was generally governed by the structure of the azolium cycle, whereas the substituents on the heterocycle had a limited impact on the activity. Ultimately, this study highlighted four of the most promising azolium halogen bond donors, which are expected to exhibit high catalytic activity.
- Bolotin, Dmitrii S.,Il'in, Mikhail V.,Novikov, Alexander S.,Suslonov, Vitalii V.,Sysoeva, Alexandra A.
-
p. 7611 - 7620
(2021/09/22)
-
- Synthesis of quinoxaline, benzimidazole and pyrazole derivatives under the catalytic influence?of biosurfactant-stabilized iron nanoparticles in water
-
Abstract: We have reported the synthesis, characterization, and catalytic applications of amorphous iron nanoparticles (FeNPs) using aqueous leaves extract of renewable natural resource Boswellia serrata plant. Synthesized FeNPs were stabilized in situ by the addition of aqueous pod extracts of Acacia concinna as a biosurfactant (pH 3.11). The structural investigation of biosynthesized nanoparticles was performed using UV–visible spectroscopy, X-ray diffraction analysis, selected area electron diffraction, energy-dispersive X-ray spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, and BET analysis. The FeNPs were amorphous in nature with average particle size ~ 19?nm and successfully employed as heterogeneous catalyst for the synthesis of quinoxaline, benzimidazole, and pyrazole derivatives in aqueous medium at ambient conditions. The FeNPs could be recycled up to five times with modest change in the catalytic activity. Graphic abstract: [Figure not available: see fulltext.].
- Arde, Satyanarayan M.,Patil, Audumbar D.,Mane, Ananda H.,Salokhe, Prabha R.,Salunkhe, Rajashri S.
-
p. 5069 - 5086
(2020/09/02)
-
- Structural characterization of benzoyl-1H-pyrazole derivatives obtained in lemon juice medium: Experimental and theoretical approach
-
Simple, one-pot, and low-cost reactions of acetylacetone with a variety of substituted benzoyl hydrazides in lemon juice, as eco-friendly medium, were performed. In reactions of benzoyl hydrazides with electron-donating groups on phenyl ring, the 1-benzoy
- Milovanovi?, Vesna,Petrovi?, Zorica D.,Novakovi?, Sla?ana,Bogdanovi?, Goran A.,Simijonovi?, Du?ica,Petrovi?, Vladimir P.
-
-
- Cu1.5PMo12O40-catalyzed condensation cyclization for the synthesis of substituted pyrazoles
-
A convenient and direct approach has been developed for the preparation of pyrazole derivatives by the condensation cyclization of hydrazines/hydrazide and 1,3-diketones in the presence of Cu1.5PMo12O40 (0.33?mol%) under mild conditions (r.t.-60?°C, 10–30?min). Notably, the reaction was found to be scalable as 99% yield was obtained when the reaction was performed at a 5-mmol scale. This solvent-free and halogen-free catalytic system represents an effective economic and environmentally friendly method for the construction of pyrazoles.
- Yang, Guo-Ping,He, Xing,Yu, Bing,Hu, Chang-Wen
-
-
- Electronic effects on the structures and catalytic properties of (pyrazol-1-yl)phenylmethanone palladium(II) complexes
-
Four new (pyrazol-1-yl)phenylmethanone ligands and their palladium(II) complexes were synthesized and characterized by various analytical techniques. The electronic properties of substituents on the phenyl ring of the ligand have significant effects on th
- Nelana, Simphiwe M.,Kumar, Kamlesh,Guzei, Ilia A.,Mahamo, Tebello,Darkwa, James
-
p. 159 - 165
(2017/08/10)
-
- Copper-catalyzed C–N cross-coupling of arylboronic acids with N-acylpyrazoles
-
A copper-catalyzed C–N bond forming reaction of arylboronic acids and N-acylpyrazoles was developed. This procedure used N-acetyl protected pyrazoles as starting material instead of free pyrazoles (NH). The reaction worked under neutral conditions and did not require any base or ligand. The reaction showed good functional group tolerance.
- Zhang, Jin,Jia, Run-Ping,Wang, Dong-Hui
-
supporting information
p. 3604 - 3607
(2016/07/21)
-
- A green protocol for catalyst-free syntheses of pyrazole in glycerol-water solution
-
An efficient green protocol for preparing pyrazole derivatives using glycerol and water as a mixture solvent is described. The advantages of the present method lie in using economic and environmentally benign solvent, no use of catalyst, mild reaction conditions and good yields.
- Min, Zhen-Li,Zhang, Qian,Hong, Xing,Cao, Xiao-Lu,Hu, Xia-Min
-
p. 3205 - 3207
(2015/12/05)
-
- An efficient practical chemo-enzymatic protocol for the synthesis of pyrazoles in aqueous medium at ambient temperature
-
An expeditious oxidative cyclocondensation reaction of hydrazines/hydrazides with 1,3-dicarbonyl compound was efficiently developed in aqueous medium using Saccharomyces cerevisae (baker's yeast) as a whole cell biocatalyst at room temperature. The method has been assigned using green chemistry measures and found to give a range of N-substituted pyrazoles with moderate to excellent yields (70-92%). The reaction progress was monitored by gas chromatography.
- Mane, Ananda,Salokhe, Prabha,More, Pallavi,Salunkhe, Rajashri
-
-
- Synthesis, structure characterization, DNA binding, and cleavage properties of mononuclear and tetranuclear cluster of copper(II) complexes
-
Two copper(II) complexes, cluster 1, and mononuclear 2, have been synthesized by reacting acetylacetone and benzohydrazide (1:1 ratio for 1 and 1:2 ratio for 2) with CuCl2 in a methanol solution. In 2, which is a new complex, the ligand acts as
- Vafazadeh, Rasoul,Hasanzade, Naime,Heidari, Mohammad Mehdi,Willis, Anthony C.
-
p. 122 - 129
(2015/04/27)
-
- Mixing with microwaves: Solvent-free and catalyst-free synthesis of pyrazoles and diazepines
-
A simple and facile condensation of hydrazines/hydrazides and diamines with 1,3-diketones/β-ketoester leads to the preparation of pyrazoles and diazepines in high yields. This eco-friendly protocol is accelerated by microwave heating and efficiently carried out without any reaction solvent or catalyst in as little as 5 min.
- Vaddula, Buchi Reddy,Varma, Rajender S.,Leazer, John
-
supporting information
p. 1538 - 1541
(2013/03/14)
-
- Hydrotrope: Green and rapid approach for the catalyst-free synthesis of pyrazole derivatives
-
An efficient synthesis of pyrazole derivatives by condensation of 1,3-diketone and hydrazines/hydrazides has been achieved in aqueous hydrotropic solution under catalyst-free conditions within a very short time. The present protocol is beneficial as it includes mild reaction conditions, shorter reaction times, use of universal solvent water, which avoids volatile organic solvents, high yields of products, and being environmentally friendly.
- Barge, Madhuri,Kamble, Santosh,Kumbhar, Arjun,Rashinkar, Gajanan,Salunkhe, Rajashri
-
p. 1213 - 1218
(2013/08/23)
-
- Sulfamic acid (H2NSO3H): A low-cost, mild, and efficient catalyst for the synthesis of substituted N-Phenylpyrazoles under solvent-free conditions
-
N-Phenylpyrazoles are synthesized by condensing phenylhydrazine and 1,3-diketones in the presence of a catalytic amount of sulfamic acid, a mild and an efficient solid acid catalyst, under solvent-free conditions. This condensation proceeds smoothly in shorter reaction time. Copyright Taylor & Francis Group, LLC.
- Shetty, Mohan R.,Samant, Shriniwas D.
-
experimental part
p. 1411 - 1418
(2012/04/17)
-
- Zn[(l)proline]2 in water: A new easily accessible and recyclable catalytic system for the synthesis of pyrazoles
-
Zn[(l)proline]2 has been found to be an efficient catalyst for the synthesis of pyrazole derivatives in pure water at room temperature. Reaction afforded moderate to excellent yield within a lesser time. Various pyrazoles which could not be prepared by other methods can be easily prepared by this method efficiently. Catalyst exhibits recyclability up to five runs. Hence our present protocol is economical and clean comprise of green reagent, solvent and catalyst.
- Kidwai, Mazaahir,Jain, Arti,Poddar, Roona
-
experimental part
p. 1939 - 1944
(2011/06/19)
-
- Nano-organocatalyst: magnetically retrievable ferrite-anchored glutathione for microwave-assisted Paal-Knorr reaction, aza-Michael addition, and pyrazole synthesis
-
Postsynthetic surface modification of magnetic nanoparticles by glutathione imparts desirable chemical functionality and enables the generation of catalytic sites on the surfaces of ensuing organocatalysts. In this article, we discuss the developments, unique activity, and high selectivity of nano-organocatalysts for microwave-assisted Paal-Knorr reaction, aza-Michael addition, and pyrazole synthesis. Their insoluble character coupled with paramagnetic nature enables easy separation of these nano-catalysts from the reaction mixture using external magnet, which eliminates the requirement of catalyst filtration.
- Polshettiwar, Vivek,Varma, Rajender S.
-
experimental part
p. 1091 - 1097
(2010/03/25)
-
- Greener and rapid access to bio-active heterocycles: room temperature synthesis of pyrazoles and diazepines in aqueous medium
-
An expeditious room temperature synthesis of pyrazoles and diazepines by condensation of hydrazines/hydrazides and diamines with various 1,3-diketones is described. This greener protocol was catalyzed by polystyrene supported sulfonic acid (PSSA) and proceeded efficiently in water in the absence of any organic solvent within 1-2 min.
- Polshettiwar, Vivek,Varma, Rajender S.
-
p. 397 - 400
(2008/09/17)
-
- Resolution of secondary alcohols using 2-acyl-3-phenyl-l-menthopyrazoles as enantioselective acylating agents
-
The chelation of AlCl3 with N-acylpyrazoles leads to structural fixation of the acyl moiety and an acceleration in the rate of acylation of secondary alcohols. The chiral environment of the fixed acyl moiety of 2-acyl-3-phenyl-l-menthopyrazole 2 causes diastereofacial selectivity in the reaction with secondary alcohols, and thus 2 behaves as an enantioselective acylating agent. By the use of 2.4 molar equivalents of racemic 1-phenylethanol 3a, 2-acetyl-3-phenyl-l-menthopyrazole 2a afforded (S)-1-phenylethyl acetate (S)-4aa enantioselectively and unreacted 3a was recovered with (R)-configuration. Furthermore, the inverse configurational preferences were observed to give (R)-4aa and (S)-3a by the addition of strongly basic amines, which sometimes behaved as catalysts for enolate formation from 2 and AlCl3. These dramatic changes in stereoselective preference should be useful properties of 2-acyl-3-phenyl-l-menthopyrazole 2 as an enantioselective acylating agent.
- Kashima, Choji,Mizuhara, Saori,Miwa, Yohei,Yokoyama, Yukihiro
-
p. 1713 - 1719
(2007/10/03)
-
- The preparation of N-acetylpyrazoles and their behavior toward alcohols
-
According to four different methods, various types of n-acylpyrazoles were prepared from the corresponding pyrazoles and carboxylic acids or their acid chlorides. Although A-acylpyrazoles were inert to alcohols under neutral or weakly basic conditions, th
- Kashima,Harada,Kita,Fukuchi,Hosomi
-
-
- Reaction of 3-Benzylidene-2,4-pentanedione and 3-Methoxymethylene-2,4-pentanedione with Aroylhydrazines
-
Aroylhydrazines 2 reacted with 3-benzylidene-2,4-pentanedione (1) to give 1-aroyl-3,5-dimethyl-1H-pyrazoles 5 and benzaldehyde aroylhydrazones 6. From the reaction of 3-methoxymethylene-2,4-pentanedione (7) with aroylhydrazines 2 the unknown N-aroyl-4-acetyl-1H-pyrazoles 9 were exclusively isolated in good yields.
- Mitkidou, Sophia,Stephanidou-Stephanatou, Julia,Stephopoulou, Helen
-
p. 441 - 444
(2007/10/02)
-