- Ni-NiO heterojunctions: a versatile nanocatalyst for regioselective halogenation and oxidative esterification of aromatics
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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.
- Bhardwaj, Nivedita,Goel, Bharat,Indra, Arindam,Jain, Shreyans K.,Singh, Ajit Kumar,Tripathi, Nancy
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p. 14177 - 14183
(2021/08/16)
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- An expedient carbon–sulfur bond formation explored through the cellulose sulfonic acid (CSA) catalyzed dithioacetal protection of carbonyl compounds
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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
- Kadam, Kailas R.
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p. 530 - 541
(2020/07/03)
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- Sulfur-Directed Ligand-Free C-H Borylation by Iridium Catalysis
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An iridium-catalyzed ortho C-H borylation reaction directed by cyclic dithioacetal moiety is disclosed. A series of borylation products were obtained in moderate to good yields under mild conditions in exclusive mono- and ortho-regioselectivity. Thus, the 1,3-dithiane or 1,3-dithiolane group serves as a remarkable effective directing group for C-H borylation without any ligand assistance. The further transformations of the borylation products are also carried out to change boryl group to other functional groups.
- Liu, Li,Wang, Guanghui,Jiao, Jiao,Li, Pengfei
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p. 6132 - 6135
(2017/11/24)
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- The directing group wins over acidity: kinetically controlled regioselective lithiation for functionalization of 2-(2,4-dihalophenyl)-1,3-dithiane derivatives
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Regioselective lithiation followed by functionalization of 2-(2,4-dihalophenyl)-1,3-dithiane derivatives with different electrophiles was achieved in good to excellent yields. When the title compound is treated with n-butyl lithium, lithiation occurs selectively at the aromatic carbon having less acidic proton despite the presence of thermodynamically more acidic 1,3-dithiane proton in the same molecule. Computationally calculated pKa values of the available reactive site protons and the experimental results suggest that the regioselective lithiation in 2-(2,4-dihalophenyl)-1,3-dithiane derivatives is not governed by thermodynamic acidity rather exclusively dictated by the kinetic removal of protons due to cooperative coordination (complex induced proximity effect, CIPE) and inductive effects of the 1,3-dihalo substituents present in the aromatic ring. By employing this regioselective functionalization, diverse 1,2,3,4-tetra-substituted aromatic compounds were prepared with ease.
- Sakthivel, Shanmugam,Kothapalli, Raveendra Babu,Balamurugan, Rengarajan
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p. 1670 - 1679
(2016/02/09)
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- Sulfonated polyanthracene-catalyzed highly efficient and chemoselective thioacetalization of carbonyl compounds and transthioacetalization of acetals and acylals
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A straightforward and highly efficient procedure for the thioacetalization of a variety of aldehydes and transthioacetalization of acylals and acetals in good to excellent yields using catalytic amounts of sulfonated polyanthracene (S-PAT) is reported. Th
- Fahid,Pourmousavi
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- Aluminum hydrogen sulfate [Al(HSO4)3] as an efficient catalyst for the preparation of thioacetals
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Aluminum hydrogen sulfate, as a heterogeneous solid acid catalyst, has been used for the mild conversion of carbonyl compounds to their thioacetals using 1,2- and 1,3-dithiol under ambient conditions with short reaction times in high to excellent yield in
- Ghashang, Majid
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p. 2837 - 2842
(2013/07/26)
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- SBA-15 functionalized sulfonic acid containing a confined hydrophobic and acidic ionic liquid: A highly efficient catalyst for solvent-free thioacetalization of carbonyl compounds at room temperature
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A novel application of SBA-15 functionalized sulfonic acid containing a confined ionic liquid has been introduced to convert various carbonyl compounds to their corresponding dithioacetals and dithioketals at room temperature and under solvent-free condit
- Karimi, Babak,Vafaeezadeh, Majid
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p. 23207 - 23211
(2013/11/19)
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- Dithioacetalization of carbonyl compounds under catalyst-free condition
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Protection of carbonyl compounds with 1,3-propanedithiol under a catalyst-free condition in nitromethane as a solvent has been described.
- Akhlaghinia, Batool,Makarem, Ata
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scheme or table
p. 575 - 581
(2012/04/23)
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- Chemoselective dithioacetalization and oxathioacetalization of carbonyl compounds using alumina sulfuric acid as catalyst
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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.
- Shaterian, Hamid Reza,Hosseinian, Asghar,Ghashang, Majid
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experimental part
p. 4097 - 4106
(2009/04/11)
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- Chemoselective dithioacetalization of carbonyl compounds using magnesium hydrogensulfate as efficient heterogeneous catalyst
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Carbonyl compounds have been successfully converted into their corresponding dithiolanes and dithianes derivatives with 1,2-ethanedithiol and 1,3-propanedithiol in excellent yield at room temperature and short reaction times using a catalytic amount of ma
- Shaterian, Hamid Reza,Hosseinian, Asghar,Ghashang, Majid,Khorami, Fahimeh
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experimental part
p. 2490 - 2501
(2009/08/07)
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- Bismuth oxide perchlorate as a highly efficient and chemoselective catalyst for thioacetalization of carbonyl compounds under solvent-free conditions
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Bismuth oxide perchlorate efficiently and chemoselectively catalyzes the thioacetalization of both aliphatic and aromatic carbonyl compounds under solvent-free conditions. Stearically hindered ketones are also thioacetalized in excellent yields with stoic
- Sunil Kumar,Thirupathi Reddy,Narsimha Reddy,Rao,Rajitha
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p. 2387 - 2389
(2007/10/03)
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- Highly efficient and chemoselective thioacetalization of carbonyl compounds catalyzed with aluminum trifluromethanesulfonate [Al(OTf)3]
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Aluminum trifluromethanesulfonate [Al(OTf)3] is a highly efficient and chemoselective catalyst for the thioacetalization of carbonyl compounds.
- Firouzabadi,Iranpoor,Kohmareh
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p. 167 - 173
(2007/10/03)
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- 2,4,4,6-Tetrabromo-2,5-cyclohexadienone (TABCO), N-bromosuccinimide (NBS) and bromine as efficient catalysts for dithioacetalization and oxathioacetalization of carbonyl compounds and transdithioacetalization reactions
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The use of 2,4,4,6-tetrabromo-2,5-cyclohexadienone (TABCO), N-bromosuccinimide (NBS), and bromine as efficient catalysts for conversion of carbonyl compounds to their cyclic and acyclic dithioacetals and 1,3-oxathiolanes under mild reaction conditions are described. These catalysts are also used for efficient transdithioacetalization of acetals, diacetals, ketals, acylals, enamines, hydrazones, and oximes with high yields in the presence of thiols.
- Iranpoor, Nasser,Firouzabadi, Habib,Shaterian, Hamid Reza,Zolfigol
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p. 1047 - 1071
(2007/10/03)
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- Heteropoly acids as heterogeneous catalysts for thioacetalization and transthioacetalization reactions
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Heteropoly acids are effective solid catalysts for the thioacetalization of carbonyl compounds. Tungstophosphoric acid (H3PW12O40), was found to be an effective and a highly selective catalyst for the thioacetalization of aldehydes, ketones and for the transthioacetalization of acetals, acylals and O,S-acetals which proceeded in excellent yields in the absence of solvent. The catalyst has also been successfully applied to the chemoselective conversion of α- or β-diketones and a β-keto ester into the corresponding dithioacetals. Sterically hindered carbonyl compounds such as camphor and benzophenone were also converted to their corresponding thioacetals in refluxing petroleum ether in 89-94percent yields. Surprisingly, anthrone was reduced to anthracene in 91percent yield.
- Firouzabadi,Iranpoor,Amani
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