57009-71-9Relevant academic research and scientific papers
Ni-NiO heterojunctions: a versatile nanocatalyst for regioselective halogenation and oxidative esterification of aromatics
Bhardwaj, Nivedita,Goel, Bharat,Indra, Arindam,Jain, Shreyans K.,Singh, Ajit Kumar,Tripathi, Nancy
, p. 14177 - 14183 (2021/08/16)
Herein, we report a facile method for the synthesis of Ni-NiO heterojunction nanoparticles, which we utilized for the nuclear halogenation reaction of phenol and substituted phenols usingN-bromosuccinimide (NBS). A remarkablepara-selectivity was achieved for the halogenated products under semi-aqueous conditions. Interestingly, blocking of thepara-position of phenol offeredortho-selective halogenation. In addition, the Ni-NiO nanoparticles catalyzed the oxidative esterification of carbonyl compounds with alcohol, diol or dithiol in the presence of a catalytic amount of NBS. It was observed that the aromatic carbonyls substituted with an electron-donating group favoured nuclear halogenation, whereas an electron-withdrawing group substitution in carbonyl compounds facilitated the oxidation reaction. In addition, the catalyst was magnetically separated and recycled 10 times. The tuned electronic structure at the Ni-NiO heterojunction controlled selectivity and activity as no suchpara-selectivity was observed with commercially available NiO or Ni nanoparticles.
An expedient carbon–sulfur bond formation explored through the cellulose sulfonic acid (CSA) catalyzed dithioacetal protection of carbonyl compounds
Kadam, Kailas R.
, p. 530 - 541 (2020/07/03)
A facile carbon–sulfur bond formation was observed through the cellulose sulfonic acid (CSA) catalyzed dithioacetal protection of carbonyl compounds. In a preliminary study, the synthesis and characterization of functionalized bio-polymer, cellulose sulph
Visible-light mediated facile dithiane deprotection under metal free conditions
Dharpure, Pankaj D.,Bhowmick, Anindita,Warghude, Prakash K.,Bhat, Ramakrishna G.
, (2019/12/09)
Visible light mediated facile and selective dithiane deprotection under metal free conditions is developed. Eosin Y (1 mol%) proved to be an effective catalyst for the dithiane deprotection under the ambient photoredox conditions. The standard household compact fluorescent light source (CFL bulb) proved to be effective under open-air conditions in aqueous acetonitrile at room temperature. The protocol that exhibits a broad substrate scope and functional group tolerance has been shown to expand to a range of transformations for the electron-rich and -deficient thioacetals and thioketals. The synthetic utility of this protocol has also been demonstrated by gram-scale application.
Synthesis of Chiral α-Aminosilanes through Palladium-Catalyzed Asymmetric Hydrogenation of Silylimines
Fan, Dongyang,Liu, Yang,Jia, Jia,Zhang, Zhenfeng,Liu, Yangang,Zhang, Wanbin
supporting information, p. 1042 - 1045 (2019/05/16)
The asymmetric hydrogenation of silylimines was first developed by using a palladium complex of a P-stereogenic diphosphine ligand as the catalyst, affording the valuable chiral α-aminosilanes with quantitative conversions and excellent enantioselectiviti
Enantio-, Regio- and Chemoselective Copper-Catalyzed 1,2-Hydroborylation of Acylsilanes
Nagy, Audric,Collard, Laurent,Indukuri, Kiran,Leyssens, Tom,Riant, Olivier
supporting information, p. 8705 - 8708 (2019/06/13)
Enantioselective synthesis of synthetically significant (α-hydroxyallyl)silanes, (α-hydroxyaryl)silanes, and (α-hydroxyalkyl)silanes is reported. The present copper-catalyzed 1,2-selective hydroborylation of acylsilanes affords the aforementioned products
A 2 - substituted - 1, 3 - dithiane derivative of the preparation method
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Paragraph 0023; 0024; 0025; 0026; 0027, (2019/06/26)
The invention provides a preparation method of a 2-substituted-1,3-dithiane derivative. The preparation method comprises the following steps: adding 1,3-dithiane (CAS:505-23-7) and 1,2-dichloroethane (DCE) or dichloromethane (DCM) into a reaction bottle, adding N-chlorosuccinimide (NCS) under ice-bath condition, and stirring for 0.5-1 h to prepare a 2-chloro-1,3-dithiane solution; and adding an aldehyde or ketone compound and a lewis acid catalyst into the above solution, and reacting to prepare the 2-substituted-1,3-dithiane derivative. By using the 1,3-dithiane solid and different types of aldehyde and keto-carbonyl compounds as raw material and using one or more of ferric trichloride, boron trifluoride diethyl etherate, methanesulfonic acid, aluminum trichloride, ferrous chloride and nickel chloride as catalysts, preparation of the 2-substituted-1,3-dithiane derivative is realized. The catalysts used in the invention are cheap and easily available, dosage of the catalysts is low and pollution of the catalysts is little. The solid raw materials used in the invention can avoid use of fetid toxic 1,3-dimercaptopropane with strong volatility, and the purpose of protecting an experimenter's body and reducing environmental pollution is realized. In addition, the preparation method has advantages of mild reaction condition, high yield, simple operation and the like.
HYDANTOINS THAT MODULATE BACE-MEDIATED APP PROCESSING
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Paragraph 0490, (2014/09/03)
In certain embodiments hydantoin compounds are provided herein that are effective to inhibit BACE activity against APP. Without being bound to a particular theory, it is believed the activity of the hydantoins identified herein appears to be associated wi
Reversed-polarity synthesis of Diaryl Ketones through palladium-catalyzed direct Arylation of 2-Aryl-1,3-dithianes
Yucel, Baris,Walsh, Patrick J.
supporting information, p. 3659 - 3667 (2015/01/09)
An umpolung approach to the synthesis of diaryl ketones has been developed based on in situ generation of acyl anion equivalents and their catalytic arylation. This method entails the base-promoted, palladium-catalyzed direct C-H arylation of 2- aryl-1,3-dithianes with aryl bromides. Use of MNACHTUNGTRENUNG( SiMe3)2 (M=Li, Na) base results in reversible deprotonation of the weakly acidic dithiane. In the presence of a Pd(NiXantphos)-based catalyst and aryl bromide, cross-coupling of the metallated 2-aryl- 1,3-dithiane takes place under mild conditions (2 h at rt) with yields as high as 96%. The resulting 2,2- diaryl-1,3-dithianes were converted into diaryl ketones by either molecular iodine, N-bromo succinimide (NBS) or Selectfluor in the presence of water. The dithiane arylation/hydrolysis can be performed in a one-pot procedure to yield a variety of diaryl ketones in good to excellent yields. This method is suitable for rapid and large-scale synthesis of diaryl ketones. A one-pot preparation of anti-cholesterol drug fenofibrate (TriCor) has been achieved on 10.0 mmol scale in 86% yield.
Reversed-polarity synthesis of diaryl ketones through palladium-catalyzed direct arylation of 2-Aryl-1,3-dithianes
Yucel, Baris,Walsh, Patrick J.
, p. 3659 - 3667 (2015/01/09)
An umpolung approach to the synthesis of diaryl ketones has been developed based on in situ generation of acyl anion equivalents and their catalytic arylation. This method entails the base-promoted, palladium-catalyzed direct C-H arylation of 2- aryl-1,3-dithianes with aryl bromides. Use of ( SiMe3)2 (M=Li, Na) base results in reversible deprotonation of the weakly acidic dithiane. In the presence of a Pd(NiXantphos)-based catalyst and aryl bromide, cross-coupling of the metallated 2-aryl- 1,3-dithiane takes place under mild conditions (2 h at rt) with yields as high as 96%. The resulting 2,2- diaryl-1,3-dithianes were converted into diaryl ketones by either molecular iodine, N-bromo succinimide (NBS) or Selectfluor in the presence of water. The dithiane arylation/hydrolysis can be performed in a one-pot procedure to yield a variety of diaryl ketones in good to excellent yields. This method is suitable for rapid and large-scale synthesis of diaryl ketones. A one-pot preparation of anti-cholesterol drug fenofibrate (TriCor) has been achieved on 10.0 mmol scale in 86% yield.
Chemoselective dithioacetalization and oxathioacetalization of carbonyl compounds using alumina sulfuric acid as catalyst
Shaterian, Hamid Reza,Hosseinian, Asghar,Ghashang, Majid
experimental part, p. 4097 - 4106 (2009/04/11)
Carbonyl compounds have been successfully converted into their corresponding dithiolane, dithiane, and oxathiolane derivatives using a catalytic amount of alumina sulfuric acid (Al2O3-SO3H) with excellent yields at room temperature in short reaction times under mild conditions. This simple method is a highly chemoselective procedure for protection of aldehydes in the presence of ketones, and the heterogeneous catalyst can be recovered and reused several times without any loss of its activity. Copyright Taylor & Francis Group, LLC.
