122-57-6Relevant articles and documents
One-pot, three-component approach to the synthesis of 3,4,5-trisubstituted pyrazoles
Kamal, Ahmed,Sastry, K. N. Visweswara,Chandrasekhar,Mani, Geeta Sai,Adiyala, Praveen Reddy,Nanubolu, Jagadeesh Babu,Singarapu, Kiran Kumar,Maurya, Ram Awatar
, p. 4325 - 4335 (2015)
An operationally simple and high yielding protocol for the synthesis of polyfunctional pyrazoles has been developed through one-pot, three-component coupling of aldehydes, 1,3-dicarbonyls, and diazo compounds as well as tosyl hydrazones. The reaction proceeds through a tandem Knoevenagel condensation, 1,3-dipolar cycloaddition, and transition metal-free oxidative aromatization reaction sequence utilizing molecular oxygen as a green oxidant. The scope of the reaction was studied by varying the aldehyde, 1,3-dicarbonyl, and diazo component individually.
Hydrotalcite reconstructed by in situ rehydration as a highly active solid base catalyst and its application in aldol condensations
Xu, Chunli,Gao, Yuan,Liu, Xihong,Xin, Ruirui,Wang, Zhen
, p. 793 - 801 (2013)
Reconstructed hydrotalcite is a highly active heterogeneous base catalyst for a wide variety of reactions. Herein, we report a procedure to effectively prepare the reconstructed hydrotalcite. Mg-Al mixed oxide, which originates from hydrotalcite, is added directly to the aqueous-phase reaction system of the aldol condensation without the protection of an inert gas. Under the reaction conditions, the reconstructed hydrotalcite is in-situ generated, and is used as a catalyst for then aldol condensation as soon as it forms, resulting in the elimination of the deactivation of reconstructed hydrotalcite. The experimental results showed that the in-situ reconstructed hydrotalcite had higher catalytic activity and water tolerance. The work provides a simple and effective method for reconstructed hydrotalcite.
Encapsulating mesoporous metal nanoparticles: Towards a highly active and stable nanoreactor for oxidative coupling reactions in water
Zou, Houbing,Dai, Jinyu,Wang, Runwei
, p. 5898 - 5901 (2019)
We design and prepare a highly active and stable nanoreactor via encapsulating various mesoporous metal nanoparticles with an amphiphilic hollow shell, which presents excellent performance in oxidative coupling reactions in water for efficient production of α,β-unsaturated ketones.
Persulfate-mediated synthesis of polyfunctionalized benzenes in water: Via the benzannulation of alkynes and α,β-unsaturated compounds
De Souza, Gabriela F. P.,Salles, Airton G.
, p. 5507 - 5511 (2019)
A persulfate-promoted metal-free route in water toward the synthesis of unprecedented polyfunctionalized benzenes is reported. In our approach, the targeted products are delivered in high to moderate yields from phenylacetylenes and α,β-unsaturated compounds via the benzannulation reaction. This method has a good scope and gives access to functionalized benzene rings that offer a wealth of opportunities for further functionalization.
A mechanistic investigation of Biginelli reaction under base catalysis
Kamal Raj,Rao, H. Surya Prakash,Manjunatha, Sulur G.,Sridharan,Nambiar, Sudhir,Keshwan, Jaikumar,Rappai, Jayan,Bhagat, Sagar,Shwetha,Hegde, Dinesh,Santhosh
, p. 3605 - 3609 (2011)
The mechanism of the three component base mediated Biginelli dihydropyrimidines synthesis was investigated using Accurate Mass TOF LC-MS-ESI and Tandem TOF LC-MS-ESI. We suggest hemiaminal as a possible intermediate leading to the formation of Biginelli product. Under our current experimental conditions we did not observe any bis-ureide as reported by ji et al.
Synthesis and crystal structure of 4,7-diaryl-5-oxo-4H-benzo[b]pyran derivatives
Cui, Bin,Chen, Li-Zhuang,Hu, Xiao-Lei,Wang, Ming,Han, Guang-Fan
, p. 900 - 904 (2012)
A green and convenient approach to the synthesis of a series of 4,7-diaryl-5-oxo-4H-benzo[b]pyran derivatives from appropriate aromatic aldehydes and 5-aryl-1,3-cyclohexanedione with malononitrile in the presence of dilute HCl as catalyst (30 mmol/L) is described. This method provides several advantages such as environmental friendliness, low cost, high yields, and simple work up procedure. The structures of all compounds were characterized by infrared (IR), mass spectrometry (MS), 1H NMR, and elemental analysis. The crystal structure of trans/cis-2-amino-3-cyano-7-(4'-methoxo- phenyl)-4-phenyl-5-oxo-4H-benzo[b]pyran, g, was determined by single crystal X-ray diffraction analysis. The crystal of compound g belongs to monoclinic with space group P 21/c, a = 8.477(3) nm, b = 18.948(6) nm, c = 24.915(7) nm, α = 90.00°, β = 107.388(11)°, γ= 90.00°, Z = 8, V = 3.819(2) nm3, R1 = 0.0754, wR2 = 0.2042.
Effects of dendritic interface on enantioselective catalysis by polymer-bound prolines
Kehat, Tzofit,Goren, Kerem,Portnoy, Moshe
, p. 394 - 401 (2012)
Dendritic effects have been observed in the past for a number of metal-based catalysts, but only rarely for organocatalysts, and particularly chiral organocatalysts. In the current study, l-proline was immobilized as an ester or amide on polyether dendritic spacers attached to polystyrene. The ester-including catalysts showed a remarkable positive dendritic effect on yield, but even more so on enantioselectivity, in the aldol reaction of acetone with aromatic aldehydes. The positive dendritic effect of the aforementioned catalytic systems on the yield, diastereo- and enantioselectivity of a three-component Mannich reaction was of an even greater magnitude. A series of experiments marked the possibility of catalysis by homogenous l-proline, detached from the resin during the reaction, highly unlikely. Model comparative studies with catalysts equipped with linear or only partially dendritic spacers emphasized the superiority of the fully dendritic spacer architecture.
Green synthesis and crystal structure of 4,7-diaryl-2-oxo(thio)-1,2,3,4,5, 6,7,8-octahydroquinazoline-5-one derivatives
Han, Guang-Fan,Cui, Bin,Chen, Li-Zhuang,Wang, Rui-Hua,Jin, Yan
, p. 312 - 316 (2011)
A green and convenient approach to the synthesis of novel 4,7-diaryl-2-oxo(thio)-1,2,3,4,5,6,7,8-octahydroquinazoline-5-one derivatives from appropriate aromatic aldehydes and 5-aryl-1,3-cyclohexanedione with urea or thiourea in the presence of dilute HCl as catalyst in water is described. This method provides several advantages such as environmental friendliness, low cost, high yields, and simple workup procedure. The structures of all compounds were characterized by elemental analysis, IR, MS, and 1H NMR. The crystal and molecular structure of 4-(4′-chlorophenyl)-7-(4′-methoxyphenyl)- 1,2,3,4,5,6,7,8-octahydroquinazoline-2,5-dione 5m have been determined by single crystal X-ray diffraction analysis. The crystal of compound 5m belongs to monoclinic with space group P-21/c, a = 1.4353 (4) nm, b = 1.4011 (4) nm, c = 0.9248 (3) nm, α = 90.00°, β = 101.242 (6)°, γ = 90.00°, Z = 4, V = 1.8241 (9) nm3, R1 = 0.0448, and wR2 = 0.1022.
Fe-catalyzed dithiane radical induced C?S bond activation?addition to α, β-unsaturated ketones
Min, Deng,Yuan, Xinyu,Liu, Teng,Liu, Jian,Tang, Shouchu
, p. 1795 - 1799 (2018)
An efficient and clean strategy to construct organosulfur compounds has been developed via a Fe-catalyzed dithiane C?S bond activation/addition process with α, β-unsaturated ketones. This C?S activation protocol exhibits excellent reactivities, and up to 92% yield of the corresponding thioether-thioester derivatives could be obtained under the mild conditions, allowing the ready preparation of a number of synthetically valuable S-linked conjugates. (Figure presented.).
A nano-fibrillated mesoporous carbon as an effective support for palladium nanoparticles in the aerobic oxidation of alcohols "on pure water"
Karimi, Babak,Behzadnia, Hesam,Bostina, Mihnea,Vali, Hojatollah
, p. 8634 - 8640 (2012)
A novel nano-fibrillated mesoporous carbon (IFMC) was successfully prepared via carbonization of the ionic liquid 1-methyl-3-phenethyl-1H-imidazolium hydrogen sulfate (1) in the presence of SBA-15. The material was shown to be an efficient and unique support for the palladium nanoparticle (PdNP) catalyst Pd@IFMC (2) in aerobic oxidation of heterocyclic, benzylic, and heteroatom containing alcohols on pure water at temperatures as low as 40 °C for the first time and giving almost consistent activities and selectivities within more than six reaction runs. The catalyst has also been employed as an effective catalyst for the selective oxidation of aliphatic and allylic alcohols at 70-80 °C. The materials were characterized by X-ray photoelectron spectroscopy (XPS), N2 adsorption-desorption analysis, transmission electron microscopy (TEM), and electron tomography (ET). Our compelling XPS and ET studies showed that higher activity of 2 compared to Pd@CMK-3 and Pd/C in the aerobic oxidation of alcohols on water might be due to the presence of nitrogen functionalities inside the carbon structure and also the fibrous nature of our materials. The presence of a nitrogen heteroatom in the carboneous framework might also be responsible for the relatively uniform and nearly atomic-scale distribution of PdNPs throughout the mesoporous structure and the inhibition of Pd agglomeration during the reaction, resulting in high durability, high stability, and recycling characteristics of 2. This effect was clearly confirmed by comparing the TEM images of the recovered 2 and Pd@CMK-3. Copyright
