- The organocatalytic highly enantioselective Knoevenagel condensation: applications in the synthesis of various chiral amide derivatives
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Abstract: In this work, efficient organocatalysts were designed, synthesized and successfully applied to the Knoevenagel condensation. In this reaction, different α-branched aldehydes were treated with various malonate compounds to give the desired produc
- Ashokkumar, Veeramanoharan,Siva, Ayyanar,Sankar, Balakrishnan
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p. 1939 - 1955
(2019/04/30)
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- A highly enantioselective asymmetric Darzens reaction catalysed by proline based efficient organocatalysts for the synthesis of di- and tri-substituted epoxides
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A new class of easily available and readily tunable proline based chiral organocatalysts was found to efficiently catalyse an unprecedented highly enantioselective asymmetric Darzens reaction of α-chloroketones and substituted α-chloroketones with various
- Ashokkumar, Veeramanoharan,Siva, Ayyanar,Ramaswamy Chidambaram
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supporting information
p. 10926 - 10929
(2017/10/13)
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- A green recyclable poly(4-vinylpyridine)-supported copper iodide nanoparticle catalyst for the chemoselective synthesis of pentaerythritol diacetals from aromatic aldehydes
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Poly(4-vinylpyridine)-supported copper(I) iodide nanoparticles have been used as an efficient, green recyclable catalyst for the chemoselective synthesis of pentaerythritol diacetals from aromatic aldehydes and pentaerythritol under solvent-free conditions. This catalyst was reused six times without any loss of its activity.
- Albadi, Jalal,Iravani, Nasir,Dehghan, Farzaneh,Shirinic, Farhad
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p. 610 - 611,2
(2020/09/16)
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- Acetalization of carbonyl compounds as pentaerythritol diacetals and diketals in the presence of cellulose sulfuric acid as an efficient, biodegradable and reusable catalyst
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This paper reports a practical and green method for the acetalization of carbonyl compounds as pentaerythritol diacetals and diketals derivatives using cellulose sulfuric acid as a biodegradable and reusable solid acid catalyst under thermal solvent-free conditions.
- Shaterian, Hamid Reza,Rigi, Fatemeh
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experimental part
p. 695 - 698
(2012/05/05)
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- Acetalation of pentaerithritol catalyzed by an Al-pillared saponite
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Acetalation of pentaerithritol has been carried out in the presence of an Al-pillared saponite. Several carbonyl compounds were used, including aldehydes and ketones. Yields between 72 and 93% were obtained in all cases, except in the case of veratraldehyde where the carbonyl group was blocked. The high conversion could be explained by diffusion effects of intermediates and electronic effects between the reactants in the transition state. The catalyst was found to be active after three cycles.
- Kannan,Sreekumar,Gil,Vicente
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experimental part
p. 1118 - 1122
(2012/06/18)
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- SO3H-functionalized ionic liquids as efficient and recyclable catalysts for the synthesis of pentaerythritol diacetals and diketals
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The efficient, simple and environmentally friendly synthesis of pentaerythritol diacetals and diketals using SO3H-functionalized ionic liquids (ILs) as catalysts was reported. The ILs showed high catalytic activities and reusabilities with good to excellent yields of the desired products. H0 (Hammett function) values and the minimum-energy geometries of SO3H-functionalized ILs were determined and the results revealed that the acidities and catalytic activities of ILs in acetalization were related to their structures. The IL [PSPy][OTf] with the shortest H-O bond distance had the strongest acidity and the highest catalytic activity in the synthesis of pentaerythritol diacetals and diketals.
- Wang, Yuanyuan,Gong, Xinxin,Wang, Zhizhong,Dai, Liyi
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experimental part
p. 7 - 16
(2010/07/09)
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- A new approach to the synthesis of diacetals (diketals) pentaerythritol catalyzed by SO3H-functionalized ionic liquids
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In this article, an efficient, simple and environmentally friendly approach to the synthesis of diacetals (diketals) pentaerythritol using SO3H-functionalized ionic liquids (ILs) as catalysts was reported. The ILs show high catalytic activity and reusability with good to excellent yields of the desired products. Hammett method has been used to determine the acidity order of these ionic liquids and the results are consistent with the catalytic activities observed in acetalization reaction. Maximum product yield of 93% was observed on using [PSPy][OTf] as catalyst and it can be reused at least 8 times without obvious activity loss.
- Wang, Yuan Yuan,Xu, Yan Nan,Wang, Zhi Zhong,Dai, Li Yi
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experimental part
p. 524 - 528
(2011/02/21)
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- N-bromosuccinimide (NBS) catalyzed highly chemoselective acetalization of carbonyl compounds using silylated diols and pentaerythritol under neutral aprotic conditions
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Various types of carbonyl compounds are efficiently converted to their 1,3-dioxanes and pentaerythritol diacetals by the use of either 1,3-bistrimethylsiloxy propane (A) or 1,3-bistrimethylsilanyloxy-2,2- bistrimethylsilanyloxymethyl propane (D) and a catalytic amount of N-bromosuccinimide (3-10 mol%) under essentially neutral aprotic condition, respectively. A variety of functionalities such as both aliphatic and phenolic -OTBDMS, -OMe, -OBz, furan ring, double bonds and more significantly phenolic -OTHP survived under the present reaction condition. The efficient conversion of two α-tertiary ketones to their cyclic acetals was also achieved using the present protocol.
- Karimi, Babak,Hazarkhani, Hassan,Maleki, Jafar
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p. 279 - 285
(2007/10/03)
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- Synthesis of diacetals from aldehydes and ketones with pentaerythritol catalysed by the ZrO2/S2O82- solid superacid
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A manipulatively simple and rapid procedure for the synthesis of diacetals from 2,2-bis(hydroxymethyl)-1, 3-propanediol with aldehydes and ketones in refluxing benzene or toluene using the ZRO2/S2O 82- solid superacid as catalyst in 80-98% yields has been described.
- Jin, Tongshou,Yang, Mina,Wang, Xin,Feng, Guoliang,Li, Tongshuang
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p. 203 - 205
(2007/10/03)
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- Synthesis of diacetals from aldehydes and ketones with pentaerythritol catalyzed by silica sulfate under microwave irradiation
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The synthesis of diacetals from pentaerythritol with aldehydes and ketones is carried out under microwave irradiation in 80-98% yields with silica sulfate as catalyst.
- Jin, Tong-Shou,Wang, Huan-Xin,Wang, Kai-Fang,Li, Tong-Shuang
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p. 2993 - 2999
(2007/10/03)
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- An efficient procedure for the synthesis of diacetals from the InCl3·4H2O catalysed reaction of 2,2-bis (hydroxymethyl)-1,3-propanediol with aldehydes or ketones
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Diacetals of carbonyl compounds are synthesised in good yields by the InCl3·4H2O catalysed condensation reactions.
- Deng, Guisheng,Ren, Tiegan
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- New applications of solid silica chloride (SiO2-Cl) in organic synthesis. Efficient preparation of diacetals of 2,2-bis(hydroxymethyl)-1,3-propanediol from different substrates and their transthioacetalization reactions. Efficient regeneration of carbonyl compounds from acetals and acylals
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A new application of solid silica chloride, an easily available and efficient catalyst for the preparation of diacetal of 2,2-bis-(hydroxymethyl)-1,3-propanediol from aldehydes, acetals, acylals, and oximes, is described. Transthioacetalization of diacetals of 2,2-bis-(hydroxymethyl)-1,3-propanediol into their corresponding 1,3-dithianes and 1,3-dithiolanes in the presence of silica chloride is presented. Efficient regeneration of carbonyl compounds from their corresponding acetals, ketals, diacetals, and acylals in the presence of this catalyst also is described.
- Firouzabadi, Habib,Iranpoor, Nasser,Hazarkhani, Hassan
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p. 2847 - 2858
(2007/10/03)
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- 2,4,4,6-Tetrabromo-2,5-cyclohexadienone (TABCO) as a versatile, efficient, and chemoselective catalyst for the acetalization and transacetalization of carbonyl compounds, the preparation of acetonides from epoxides and acylals (1,1-diacetates) from aldehydes
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The efficient and chemoselective preparation of acetals and ketals from carbonyl compounds, transacetalization reactions, the conversion of epoxides to acetonides, and the preparation of acylals from aldehydes in the presence of catalytic amounts of 2,4,4,6-tetrabromo-2,5-cyclohexadienone (TABCO) are described.
- Firouzabadi, Habib,Iranpoor, Nasser,Shaterian, Hamid Reza
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p. 2195 - 2205
(2007/10/03)
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- Synthesis of diacetals by condensation of carbonyl compounds with bis(hydroxymethyl)-1,3-propanediol catalysed by expansive graphite
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Synthesis of diacetals from 2,2-bis(hydroxymethyl)-1,3-propanediol with aldehydes and ketones under catalysis of expansive graphite in refluxing benzene or toluene in good to excellent yield has been described.
- Jin, Tong-Shou,Li, Tong-Shuang,Zhang, Zhan-Hui,Yuan, Yan-Jun
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p. 1601 - 1606
(2007/10/03)
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- A practical and efficient procedure for preparation of diacetals from 2,2-bis (hydroxymethyl) propane-1,3-diol with aldehydes and ketones catalysed by anhydrous ferrous sulfate
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Synthesis of diacetals in excellent yields from aldehydes and ketones with 2,2-bis(hydroxymethyl)propane-1,3-diol is carried out in refluxing benzene or toluene with anhydrous ferrous sulfate as catalyst.
- Jin, Tong-Shou,Ma, Yan-Ran,Li, Tong-Shuang,Wang, Jian-Xin
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p. 268 - 269
(2007/10/03)
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- Montmorillonite Clays Catalysis. Part 12.1 An Efficient and Practical Procedure for Synthesis of Diacetals from 2,2-Bis(hydroxymethyl)propane-1,3-diol with Carbonyl Compounds
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Preparation of diacetals from 2,2-bis(hydroxymethyl)propane-1,3-diol with aldehydes and ketones is catalysed by montmorillonite clays in refluxing benzene or toluene in good to excellent yield.
- Zhang, Zhan-Hui,Li, Tong-Shuang,Jin, Tong-Shou,Li, Ji-Tai
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p. 640 - 641
(2007/10/03)
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