- Application of poly(Vinylbenzyltrimethylammonium tribromide) resin as an efficient polymeric catalyst in the acetalization and diacetylation of benzaldehydes
-
The applications of a new supported tribromide reagent (poly(vinylbenzyltrimethylammonium tribromide) resin) were reported. This supported tribromide resin was used as a catalyst in the acetalization and diacetylation of benzaldehydes under mild conditions with high efficiency. The effects of solvents, and amount of the supported tribromide resin on the reactions were investigated. Under the optimal conditions, most of acetal and 1,1-diacetates of benzaldehydes were selectively obtained in excellent yields.
- Han, Bingbing,Hu, Junjun,Li, Xianwei,Zheng, Zubiao
-
supporting information
p. 287 - 293
(2021/04/28)
-
- Robust acidic pseudo-ionic liquid catalyst with self-separation ability for esterification and acetalization
-
The novel acidic pseudo-ionic liquid catalyst with self-separation ability has been synthesized through the quaternization of triphenylphosphine and the acidification with silicotungstic acid. The pseudo-IL showed high activities for the esterification with average conversions over 90%. The pseudo-IL showed even higher activities for acetalization than traditional sulfuric acid. The homogeneous catalytic process benefited the mass transfer efficiency. The pseudo-IL separated from the reaction mixture automatically after reactions, which was superior to other IL catalysts. The high catalytic activities, easy reusability and high stability were the key properties of the novel catalyst, which hold great potential for green chemical processes.
- Shi, Yingxia,Liang, Xuezheng
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p. 1413 - 1421
(2019/05/04)
-
- Highly regioselective α-formylation and α-acylation of BODIPY dyes via tandem cross-dehydrogenative coupling with in situ deprotection
-
A metal-free C-H formylation and acylation of BODIPY dyes using a variety of dioxolane derivatives as aldehyde equivalents is reported, providing a postfunctionalization method for controllable synthesis of BODIPYs with carbonyl groups at 3,5-positions vi
- Lv, Fan,Yu, Yang,Hao, Erhong,Yu, Changjiang,Wang, Hua,Boens, No?l,Jiao, Lijuan
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supporting information
p. 5121 - 5128
(2019/05/29)
-
- Utilization of 1,3-Dioxolanes in the Synthesis of α-branched Alkyl and Aryl 9-[2-(Phosphonomethoxy)Ethyl]Purines and Study of the Influence of α-branched Substitution for Potential Biological Activity
-
Syntheses of α-branched alkyl and aryl substituted 9-[2-(phosphonomethoxy)ethyl]purines from substituted 1,3-dioxolanes have been developed. Key synthetic precursors, α-substituted dialkyl [(2-hydroxyethoxy)methyl]phosphonates were prepared via Lewis acid mediated cleavage of 1,3-dioxolanes followed by reaction with dialkyl or trialkyl phosphites. The best preparative yields were achieved under conditions utilizing tin tetrachloride as Lewis acid and triisopropyl phosphite. Attachment of purine bases to dialkyl [(2-hydroxyethoxy)methyl]phosphonates was performed by Mitsunobu reaction. Final α-branched 9-[2-(phosphonomethoxy)ethyl]purines were tested for antiviral, cytostatic and antiparasitic activity, the latter one determined as inhibitory activity towards Plasmodium falciparum enzyme hypoxanthine-guanine-xanthine phosphoribosyltransfesase. In most cases biological activity was only marginal.
- Pomeisl, Karel,Pohl, Radek,Snoeck, Robert,Andrei, Graciela,Kre?merová, Marcela
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p. 119 - 156
(2019/01/04)
-
- Chemoselective Nucleophilic Functionalizations of Aromatic Aldehydes and Acetals via Pyridinium Salt Intermediates
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The development of a novel chemoselective functionalization can diversify the strategy for synthesizing the target molecules. The perfect chemoselectivity between aromatic and aliphatic aldehydes is difficult to achieve by the previous methods. The aromatic aldehyde-selective nucleophilic addition in the presence of aliphatic aldehydes was newly accomplished. Namely, the aromatic aldehyde-selective nucleophilic addition using arenes and allyl silanes proceeded in the presence of trialkylsilyl triflate and 2,2′-bipyridyl, while the aliphatic aldehydes completely remained unchanged. The reactive pyridinium-type salt intermediate derived from an aromatic aldehyde chemoselectively underwent the nucleophilic substitution. Moreover, the aromatic acetals as the protected aldehydes could be directly transformed into similar pyridinium salt intermediates, which reacted with various nucleophiles coexisting with the aliphatic aldehydes.
- Kawajiri, Takahiro,Kato, Maho,Nakata, Hiroki,Goto, Ryota,Aibara, Shin-Yo,Ohta, Reiya,Fujioka, Hiromichi,Sajiki, Hironao,Sawama, Yoshinari
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p. 3853 - 3870
(2019/03/07)
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- 8-Hydroxy-2-methylquinoline-modified H4SiW12O40: A reusable heterogeneous catalyst for acetal/ketal formation
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A heteropoly acid based organic hybrid heterogeneous catalyst, HMQ-STW, was prepared by combining 8-hydroxy-2-methylquinoline (HMQ) with Keggin-structured H4SiW12O40 (STW). The catalyst was characterized via elemental analysis, X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermogravimetric analysis (TG) and potentiometric titration analysis. The catalytic performance of the catalyst was assessed in the ketalization of ketones with glycol or 1,2-propylene glycol. Various reaction parameters, such as the glycol to cyclohexanone molar ratio, catalyst dosage, reaction temperature and time, were systematically examined. HMQ-STW exhibited a relatively high yield of corresponding ketal, with 100% selectivity under the optimized reaction conditions. Moreover, catalytic recycling tests demonstrated that the heterogeneous catalyst exhibited high potential for reusability, and it was revealed that the organic modifier HMQ plays an important role in the formation of a heterogeneous system and the improvement of structural stability. These results indicated that the HMQ-STW catalyst is a promising new type of heterogeneous acid catalyst for the ketalization of ketones.
- Liu, Li-Jun,Luan, Qing-Jie,Lu, Jing,Lv, Dong-Mei,Duan, Wen-Zeng,Wang, Xu,Gong, Shu-Wen
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p. 26180 - 26187
(2018/08/04)
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- House bulb light-induced photochemical acetalization of carbonyl compounds catalyzed by Eosin Y
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We have systematically studied the reactions of acetalization and found that high reaction efficiency can be achieved using cheap and readily available organic Eosin Y as catalyst. The reaction proceeds smoothly under house bulbs and shows excellent functional group tolerance. The substrates of the reaction system are compatible with aromatic aldehydes, aliphatic aldehydes, aromatic ketones, and cyclic ketones with high yields.
- Zhou, Quan,Jia, Tao,Li, Xiao-Xuan,Zhou, Lin,Li, Chang-Jiang,Feng, Yi-Si
-
supporting information
p. 1068 - 1075
(2018/05/23)
-
- Visible-light-induced acetalization of aldehydes with alcohols
-
In this work, we have achieved a simple and general method for acetalization of aldehydes by means of a photochemical reaction under low-energy visible light irradiation. A broad range of aromatic, heteroaromatic, and aliphatic aldehydes have been protected under neutral conditions in good to excellent yields using a catalytic amount of Eosin Y as the photocatalyst. Our visible light mediated acetalization strategies are successful for more challenging acid-sensitive aldehydes and sterically hindered aldehydes. Notably, this protocol is chemoselective to aldehydes, while ketones remain intact.
- Yi, Hong,Niu, Linbin,Wang, Shengchun,Liu, Tianyi,Singh, Atul K.,Lei, Aiwen
-
supporting information
p. 122 - 125
(2017/11/27)
-
- Phosphorylated Polyacrylonitrile Fibers as an Efficient and Greener Acetalization Catalyst
-
A novel solid acid catalyst (PANEAPF) is developed by immobilization of phosphoric acid on polyacrylonitrile fiber through covalent bonding. Various characterization techniques such as elemental analysis (EA), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), etc. are utilized to confirm the successful grafting and the stability of the fiber catalysts during application. PANEAPF shows high catalytic activity in the acetalization of aldehydes owing to the high utilization efficiency of its functionalized acid sites. In addition, the strong polarity micro-environment in the surface layers of PANEAPF make it highly suitable for catalytic application in both water and alcohol. Furthermore, the fiber catalyst can be applied to the acetalization of aldehydes in a continuous-flow process at room temperature, and shows excellent reactivity and superior recyclability (over 20 times). The many advantages of PANEAPF such as simple preparation, convenient regulation of acid amount, high durability, and eco-friendly process make it very attractive for fixed-bed reactors in the chemical industry.
- Xu, Gang,Cao, Jian,Zhao, Yali,Zheng, Lishuo,Tao, Minli,Zhang, Wenqin
-
supporting information
p. 2565 - 2575
(2017/09/25)
-
- Cyclopentyl methyl ether-NH4X: A novel solvent/catalyst system for low impact acetalization reactions
-
Cyclopentyl methyl ether, a low impact ether forming a positive azeotrope with water, was successfully employed as a solvent in the synthesis of 1,3-dioxanes and 1,3-dioxolanes carried out under Dean-Stark conditions by the acetalization of aliphatic and aromatic aldehydes or ketones, employing ammonium salts as environmentally friendly acidic catalysts.
- Azzena, Ugo,Carraro, Massimo,Mamuye, Ashenafi Damtew,Murgia, Irene,Pisano, Luisa,Zedde, Giuseppe
-
supporting information
p. 3281 - 3284
(2015/06/25)
-
- Highly efficient acetalization of carbonyl compounds catalyzed by anilin-aldehyde resin salts
-
A mild procedures for the syntheses of ethylene acetals and dimethyl acetals from the corresponding aldehydes and ketones catalyzed by 1mol% of anilinealdehyde resin salts are described. This method is also useful for the synthesis of dimethyl acetals of diaryl ketones.
- Tanemura, Kiyoshi,Suzuki, Tsuneo
-
supporting information
p. 797 - 799
(2015/06/22)
-
- Synthesis and characterization of a tetracationic acidic organic salt and its application in the synthesis of bis(indolyl)methanes and protection of carbonyl compounds
-
A new tetracationic acidic organic salt (TCAOS) based on DABCO was prepared, characterized and applied as an eco-friendly, powerful and reusable catalyst for the synthesis of bis(indolyl)methanes from indoles and carbonyl compounds in water with high turnover frequency (TOF). Also, this catalyst was successfully applied for acetalization of carbonyl compounds with diols under solvent-free conditions.
- Halimehjani, Azim Ziyaei,Hooshmand, Seyyed Emad,Shamiri, Elham Vali
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p. 21772 - 21777
(2015/03/18)
-
- Synthesis of 4-unsubstituted 2H-1,2,3-benzothiadiazine 1,1-dioxides via ortho lithiation of protected benzaldehyde derivatives
-
Variously substituted 2-phenyl-1,3-dioxolanes and 2-(2-bromophenyl)-1,3- dioxolanes, prepared from the corresponding benzaldehydes, were lithiated ortho to the acetal group. Reaction of the lithio derivatives with sulfur dioxide led to the lithium sulfinate salts, which gave, upon oxidative chlorination with sulfuryl chloride, the corresponding benzenesulfonyl chlorides. Then, depending on the aromatic substitution pattern of the molecule, several protocols were elaborated for the functional group transformations leading to the target compounds. Ring closure was performed with hydrazine hydrate or acetylhydrazine, in the latter case with one-pot removal of the acetyl group. The 4-unsubstituted 2H-1,2,3-benzothiadiazine 1,1-dioxides thus obtained are potential drug candidates based on their structural similarity to biologically active phthalazinones.
- Porcs-Makkay, Márta,Lukács, Gyula,Pandur, Angéla,Simig, Gyula,Volk, Balázs
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p. 286 - 293
(2014/01/06)
-
- Acetalization of aldehydes and ketones over H4[SiW 12O40] and H4[SiW12O 40]/SiO2
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H4[SiW12O40] (H-SiW12) is demonstrated to be able to efficiently catalyze the acetalization of aldehydes and ketones with ethylene glycol and 1,3-propanediol. Nevertheless, the possible leaching and the recycling of H-SiW12 are two major disadvantages that largely restrict its further application in industry. Moreover, H 4[SiW12O40] tends to deactivate strong proton sites due to the small surface area of 10 m2 g-1. Due to interactions with surface silanol groups, the proton sites of polyoxometalates (POMs) on SiO2 are less susceptible to deactivation. As such, immobilization of H4[SiW12O40] onto SiO 2 leads to the heterogeneous catalyst H4[SiW 12O40]/SiO2 (H-SiW12/SiO 2), which can catalyze the acetalization of aldehydes and ketones with ethylene glycol and 1,3-propanediol selectively and efficiently without the need of a drying agent. The acetalization process can proceed smoothly at a relatively low temperature under solvent-free conditions. The catalyst of H 4[SiW12O40]/SiO2 can be recycled at least ten times without an obvious decrease in its catalytic activity. As far as we know, the TONs of the H-SiW12/SiO2-catalyzed acetalization of cyclohexanone with ethylene glycol, and benzaldehyde with 1,3-propanediol are the highest reported so far.
- Zhao, Shen,Jia, Yueqing,Song, Yu-Fei
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p. 2618 - 2625
(2014/07/22)
-
- A facile and efficient protocol for esterification and acetalization in a PEG1000-D(A)IL/toluene thermoregulated catalyst-media combined systems
-
A novel efficient and recyclable temperature-dependent biphasic catalyst and reaction media combined system comprised of PEG-1000 linked dicationic acidic ionic liquid and toluene was developed and applied in esterification of aromatic acids and acetalization of aromatic aldehydes with good to excellent yields. This system is characteristic of temperature-dependent reversible biphasic property, simple and facile recyclability, high catalytic activity and extensive substrate and reaction adaptability.
- Wang, Yinglei,Zhi, Huizhen,Luo, Jun
-
-
- Homologative trifluoromethylation of acetals
-
Trifluoroethyl α-insertion of acetals has been developed. Aromatic, heteroaromatic, and alkenyl acetals react with in situ generated (trifluoromethyl)diazomethane in the presence of antimony(V) chloride to furnish α-trifluoromethyl acetals. A stereoselective version of this transformation exploiting the acetal as a chiral auxiliary is also presented. Georg Thieme Verlag Stuttgart · New York.
- Hamilton, James Y.,Morandi, Bill,Carreira, Erick M.
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p. 1857 - 1862
(2013/07/26)
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- A mild, room-temperature protection of ketones and aldehydes as 1,3-dioxolanes under basic conditions
-
Protection of ketones or aldehydes as 1,3-dioxolane derivatives proceeds within minutes at room temperature in the presence of N- hydroxybenzenesulfonamide, its O-benzyl derivative, or the tosyl analogue, in the absence of strong protonic acids, and in the presence of base (Et). Acid-sensitive groups such as O-THP, O-TBS, or N-Boc are unaffected. Copyright
- Hassner, Alfred,Bandi, Chennakesava Reddy,Panchgalle, Sharad
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p. 2773 - 2776
(2013/02/21)
-
- Bis(perfluorooctanesulfonyl)imide supported on fluorous silica gel: Application to protection of carbonyls
-
The immobilization of bis(perfluorooctanesulfonyl)imide (HNPf2) on fluorous silica gel (FSG) and its utilization in protection of carbonyls have been investigated. This system is reasonably general and can be applied to converting several carbonyls to the corresponding acetals and ketals in good to excellent yields. There is no need for the use of anhydrous solvents or inert atmosphere. Recycling studies have shown that the FSG-supported HNPf2 catalyst can be readily recovered and reused several times without significant loss of activity.
- Hong, Mei,Xiao, Guomin
-
experimental part
p. 121 - 126
(2012/08/28)
-
- Mesoporous sulfated zirconia mediated acetalization reactions
-
A novel, convenient, one step synthetic procedure for the synthesis of mesoporous sulfated zirconia (m-SZ) using zirconium carbonate complex and its use as solid acid catalyst for the acetalization of different carbonyl compound is reported. The high specific BET surface area (234 m2 g -1) of m-SZ is achieved after the removal of the surfactant (cetyltrymethylammonium bromide, CTAB) through calcination at 550 °C for 6 h. Microscopic analysis indicated the presence of spherical particles with worm like pores. DRIFT (diffuse reflectance FTIR) of pyridine adsorbed m-SZ and NH3-TPD (temperature programmed desorption) analysis suggested the presence of appreciable amount of Bro?nsted acid sites. The synthesized m-SZ showed high catalytic activity towards protection of carbonyl compounds through acetal/ketal formation. For the open ketal (from cyclohexanone and methanol) 97% conversion with 100% selectivity was obtained in 1 h at room temperature under solvent free condition. The catalyst can be easily recycled after separation from the reaction system without considerable loss in catalytic activity.
- Sinhamahapatra, Apurba,Sutradhar, Narottom,Ghosh, Malay,Bajaj, Hari C.,Panda, Asit B.
-
experimental part
p. 87 - 93
(2012/04/10)
-
- Acetalization of carbonyl compounds catalyzed by bismuth triflate under solvent-free conditions
-
Carbonyl compounds were converted to the corresponding 1,3-dioxolanes and 1,3-dioxanes with ethylene glycol and 1,3-propandiol in the presence of bismuth triflate under solvent-free conditions. In addition, high chemoselective protection of aldehydes in the presence of ketones has been achieved.
- Aliyan, Hamid,Fazaeli, Razieh,Massah, Ahmad Reza,Momeni, Ahmad Reza,Naghash, Hamid Javaherian,Moeinifard, Behzad
-
experimental part
p. 873 - 876
(2012/04/05)
-
- [Hmim]3PW12O40: A high-efficient and green catalyst for the acetalization of carbonyl compounds
-
[Hmim]3PW12O40 was developed and used in the acetalization of carbonyl compounds in excellent yields. The ionic liquid-heteropoly acid hybrid compound and reaction medium formed temperature-dependent phase-separation system with the ease of product as well as catalyst separation. The catalyst was recycled more than 10 times without any apparent loss of catalytic activity.
- Dai, Yan,Li, Bin Dong,Quan, Heng Dao,Lü, Chun Xu
-
experimental part
p. 678 - 681
(2011/10/31)
-
- Bismuth compounds in organic synthesis: Synthesis of dioxanes, dioxepines, and dioxolanes catalyzed by bismuth(III) triflate
-
A simple method for the synthesis of 1,3-dioxolanes from carbonyl compounds has been developed using 1,2-bis(trimethylsilyloxy)ethane in the presence of bismuth(III) triflate as a catalyst. The bismuth(III) triflate catalyzed synthesis of a range of dioxanes and dioxepines has also been developed. In these latter cases, the carbonyl compound is treated with a diol, and triethyl orthoformate is used as a water scavenger. All these methods avoid the use of a Dean-Stark trap. Georg Thieme Verlag Stuttgart.
- Podgorski, Daniel M.,Krabbe, Scott W.,Le, Long N.,Sierszulski, Paul R.,Mohan, Ram S.
-
experimental part
p. 2771 - 2775
(2010/10/02)
-
- Highly efficient and chemoselective acetalization of carbonyl compounds catalyzed by new and reusab e zirconyl triflate, zr0(0tf)2
-
Various types of aromatic aldehydes were efficiently converted to their corresponding 1,3-dioxanes and 1,3-dioxolane with 1,3-propanediol and ethylene glycol, respectively, in the presence of catalytic amount of ZrO(OTf) 2 in acetonitrile at room temperature. The catalyst can be reused several times without loss of its catalytic activity. Very short reaction times, selective acetalization of aromatic aldehydes in the presence of aliphatic aldehydes and ketones, very mild reaction conditions, reusability of the catalyst, and easy workup are noteworthy advantages of this method.
- Moghadam, Majid,Mohammadpoor-Baltork, Iraj,Tangestaninejad, Shahram,Mirkhani, Valiollah,Yazdani, Parvin,Ghorjipoor, Saeedeh
-
experimental part
p. 131 - 135
(2009/09/30)
-
- Concise synthesis of telmisartan via decarboxylative cross-coupling
-
(Chemical Equation Presented) An efficient synthesis of the angiotensin II receptor antagonist telmisartan is presented involving a decarboxylative cross-coupling of isopropyl phthalate (1) with 2-(4-chlorophenyl)-1,3-dioxolane (2c) as the key step (85% yield). The benzimidazole moiety is constructed regioselectively via a reductive animation-condensation sequence, replacing the previously published route via alkylation of the preformed benzimidazole. The product is obtained in an overall yield of 35% in a convergent synthesis with the longest sequence consisting of eight steps.
- Goossen, Lukas J.,Knauber, Thomas
-
supporting information; experimental part
p. 8631 - 8634
(2009/04/11)
-
- o-benzenedisulfonimide as reusable bronsted acid catalyst for acid-catalyzed organic reactions
-
Acid-catalyzed organic reactions, such as etherification, esterification, acetal synthesis, cleavage, and interconversion, and pinacol rearrangement were carried out in the presence of catalytic amounts of o-benzenedisulfonimide as Bronsted acid catalyst; the conditions were mild and selective. The catalyst was easily recovered and purified, ready to be used in further reactions, with economic and ecological advantages. Georg Thieme Verlag Stuttgart.
- Barbero, Margherita,Cadamuro, Silvano,Dughera, Stefano,Venturello, Paolo
-
p. 1379 - 1388
(2008/12/21)
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- Mild and efficient chemoselective synthesis of acetals and geminal diacetates (acylals) from aldehydes using lanthanum(III) nitrate hexahydrate
-
A mild and efficient chemoselective method has been developed for the preparation of acetals and gem-diacetates in good to excellent yields through a reaction of aldehydes with ethlyleneglycol or acetic anhydride using catalytic amounts of lanthanum(III) nitrate hexahydrate as a catalyst under solvent-free conditions. Copyright Taylor & Francis Group, LLC.
- Srinivasulu,Suryakiran,Rajesh,Malla Reddy,Venkateswarlu
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p. 1753 - 1759
(2008/09/20)
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- A green procedure for the protection of carbonyl compounds catalyzed by iodine in ionic liquid
-
Aldehydes and ketones are protected with ethylene glycol in the presence of a catalytic amount of iodine in PEG ionic liquid (IL 400) under mild conditions to afford the corresponding ketals in good yields. The recovery of iodine is facilitated by the ionic liquid. The recovered catalyst was reused six times with consistent activity.
- Ren, Yi-Ming,Cai, Chun
-
body text
p. 7110 - 7112
(2015/04/15)
-
- Formation of dioxolane on the surface of silica-sulphuric acid in dry media - Chemoselective protection of aryl aldehydes
-
Chemoselective protection of aryl aldehydes can be accomplished through the formation of dioxolane on the surface of silica-sulphuric acid under solvent-free conditions where aliphatic aldehydes, dialkyl ketones, aryl alkyl ketones, and diaryl ketones rem
- Saha, Manabendra,Roy, Sanchita,Chaudhuri, Subrata Kumar,Bhar, Sanjay
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p. 1989 - 1993
(2008/02/04)
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- Acid-free, organocatalytic acetalization
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The acid-free, organocatalytic acetalization of various aldehydes and ketones with N,N′-bis[3,5-bis(trifluoromethyl)phenyl]thiourea is presented. The neutral, double hydrogen bonding thiourea catalyst can be used at very low loadings of 0.01-1 mol% at room temperature to furnish the respective acetals in 65-99% yield at turnover frequencies around 600 h-1. Acid-labile TBDMS-protected as well as unsaturated aldehydes can be converted efficiently into their acetals utilizing this very mild and highly practical method.
- Kotke, Mike,Schreiner, Peter R.
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p. 434 - 439
(2007/10/03)
-
- Regioselectivity in arene-catalyzed reductive lithiation of acetals of chlorobenzaldehydes
-
The regioselectivity of arene-catalyzed reductive lithiation of acetals of chlorobenzaldehydes strongly depends on the form of lithium metal employed as a reducing agent. According to previous findings, naphthalene catalyzed reductions run in the presence of lithium powder (high Na content) led to competitive metalations of both aromatic carbon-chlorine and benzylic carbon-oxygen bonds. At variance with these results, naphthalene catalyzed reductions run in the presence of lithium wire (either high or low Na content) led to highly regioselective metalation of aromatic carbon-chlorine bonds. These results disclose new possibilities of selective applications of arene-catalyzed reductive lithiation reactions.
- Azzena, Ugo,Dettori, Giovanna,Sforazzini, Giuseppe,Yus, Miguel,Foubelo, Francisco
-
p. 1557 - 1563
(2007/10/03)
-
- Intermolecular reactions of chlorohydrine anions: Acetalization of carbonyl compounds under basic conditions
-
Nonenolizable aldehydes and ketones react with 2-chloroethanol and 3-chloropropanol under basic conditions (t-BuOK, DMF/THF) with formation of 2-substituted 1,3-dioxolanes and 1,3-dioxanes, respectively. Conversion of the two-step addition-alkylation process depends on the electrophilicity of the carbonyl group that governs the equilibrium of addition of chloroalkoxides. This method of protection of carbonyl groups in the form of cyclic acetals under kinetically controlled conditions is complementary to the acid-catalyzed reaction with diols.
- Barbasiewicz, Michal,Makosza, Mieczyslaw
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p. 3745 - 3748
(2007/10/03)
-
- I2-mediated photochemical preparation of 2-substituted 1,3-dioxolanes and tetrahydrofurans from alcohols with polymer-supported hypervalent iodine reagent, PSDIB
-
Various 2-substituted 1,3-dioxolanes, 1,3-dioxanes, and tetrahydrofurans were obtained selectively in good to moderate yields from the corresponding alcohols with PSDIB in the presence of iodine under irradiation conditions. Moreover, PSDIB was repeatedly used for the same reactions keeping good yield of the cyclic product.
- Teduka, Tomomasa,Togo, Hideo
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p. 923 - 926
(2007/10/03)
-
- Acidic properties of sulfonic acid-functionalized FSM-16 mesoporous silica and its catalytic efficiency for acetalization of carbonyl compounds
-
Propyl-sulfonic acid-functionalized FSM-16 mesoporous silica (SO 3H-FSM) is prepared by a conventional post-modification method. For the acetalization of carbonyl compounds with ethylene glycol, SO 3H-FSM shows a higher rate and 1,3-dioxolane yield than conventional heterogeneous solid acids such as zeolites, montmorillonite K10 clay, silica-alumina, and the sulfonic resin. SO3H-FSM is stable during the reaction, with no leaching and deactivation of sulfonic acid groups, and is reusable without loss of its activity. The acidity and hydrophilicity of SO 3H-FSM are well characterized by the microcalorimetry of NH 3 adsorption, NH3-TPD, and H2O-TPD, and the result is compared with those for various aluminosilicate zeolites (HZSM5, HBEA, HY) and K10 clay. It is found that NH3-TPD is not suitable for characterizing the acidity of SO3H-FSM, because the decomposition of SO3H groups on SO3H-FSM begins above 200°C. An NH 3 adsorption microcalorimetric experiment at 150°C shows that, compared with HZSM5, SO3H-FSM has a smaller number of acid sites but has a similar number of strong acid sites with ammonia adsorption heat above 140 kJ mol-1. Comparison of the structural properties and catalytic results shows that a large pore diameter and low hydrophilicity are required to obtain high activity. Bronsted acid sites with a relatively strong acid strength are more suitable for this reaction, but the high acid concentration is not indispensable. The high activity of SO3H-FSM should be caused by the presence of the strong Bronsted acid sites in the mesopore with a relatively low hydrophilicity, where both reactants can smoothly access the acid sites.
- Shimizu, Ken-Ichi,Hayashi, Eidai,Hatamachi, Tsuyoshi,Kodama, Tatsuya,Higuchi, Tomoya,Satsuma, Atsushi,Kitayama, Yoshie
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p. 131 - 138
(2007/10/03)
-
- A simple, efficient and general procedure for acetalization of carbonyl compounds and deprotection of acetals under the catalysis of indium(III) chloride
-
Indium (III) chloride efficiently catalyzes the protection of a variety of aldehydes and ketones to their corresponding 1,3-dioxolanes and dialkyl acetals in refluxing cyclohexane. On the other hand, deprotection of acetals is also achieved in refluxing aqueous methanol under the catalysis of indium(III) chloride.
- Ranu, Brindaban C.,Jana, Ranjan,Samanta, Sampak
-
p. 446 - 450
(2007/10/03)
-
- An efficient procedure for acetalization of carbonyl compounds with P 2O5/SiO2
-
P2O5 as a dehydrating agent can be used for acetalization of carbonyl compounds. This reaction is very fast with high yield and also comparable with acetal formation by using microwave irradiation.
- Mirjalili, Bibi Fatemeh,Zolfigol, Mohammad Ali,Bamoniri, Abdolhamid,Amrollahi, Mohammad Ali,Hazar, Azizeh
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p. 1397 - 1401
(2007/10/03)
-
- A simple and practical synthetic protocol for acetalisation, thioacetalisation and transthioacetalisation of carbonyl compounds under solvent-free conditions
-
A wide variety of carbonyl compounds can be converted smoothly to the corresponding acetals on treatment with alcohols or diols and triethyl orthoformate in the presence of a catalytic amount of (bromodimethyl)sulfonium bromide at room temperature. Similarly, various carbonyl compounds can be transformed into the corresponding dithioacetals on reaction with thiol or dithiols at room temperature by employing the same catalyst without any solvent. Moreover, O,O-acetals can also be converted into the corresponding dithioacetals under identical conditions. Some of the major advantages are mild reaction conditions, a high degree of efficiency, compatibilty with other protecting groups and the lack of solvents, particularly for thioacetalisation. In addition, no brominations occur at the double bond or α to the keto position or even in the aromatic ring under these experimental conditions. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
- Khan, Abu T.,Mondal, Ejabul,Ghosh, Subrata,Islam, Samimul
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p. 2002 - 2009
(2007/10/03)
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- Non-acid catalytic acetalisation of aldehydes with diols in ionic liquids
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The acetalisation of aldehydes with diols to corresponding 1,3-dioxolanes has been accomplished using ionic liquids as catalyst and reaction media. In the reaction process the removal of water produced and other catalysts were not necessary. High conversion and good selectivity were obtained when using HMImBF4, which could be easily recycled and reused.
- Zhang, Fan,Xu, Dan-Qian,Luo, Shu-Ping,Liu, Bao-You,Du, Xiao-Hua,Xu, Zhen-Yuan
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p. 773 - 774
(2007/10/03)
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- An efficient procedure for protection of carbonyls in Br?nsted acidic ionic liquid [Hmim]BF4
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Protection of carbonyls as acetals or ketals using Br?nsted acidic ionic liquid [Hmim]BF4 as catalyst as well as solvent was investigated. Satisfactory results were obtained for the protection of carbonyls as cycloacetals or ketals with diols. The product can be separated conveniently from the reaction system, and the ionic liquid can be reused after removal of water.
- Wu, Hai-Hong,Yang, Fan,Cui, Peng,Tang, Jie,He, Ming-Yuan
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p. 4963 - 4965
(2007/10/03)
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- Polyaniline-Supported Sulfuric Acid Salt as a Powerful Catalyst for the Protection and Deprotection of Carbonyl Compounds
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Structurally different carbonyl compounds were converted into their corresponding cyclic acetals using polyaniline-sulfate salt as catalyst in dry toluene in excellent yield. In turn, useful deacetalization in aqueous medium was demonstrated. Chemoselective protection of carbonyl compounds was also demonstrated. The advantages of the polyaniline-sulfate salt are ease of preparation and handling, stability, reusability and activity.
- Palaniappan, Srinivasan,Narender, Puli,Saravanan, Chandrasekaran,Rao, Vaidya Jayathirtha
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p. 1793 - 1796
(2007/10/03)
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- Microwave promoted selective preparation of acetals and esters from aldehydes
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A new selective method of acetalization of aldehydes and cyclic ketones with 1,2-diols or alcohols catalyzed by iodine under microwave irradiation is reported. Depending upon the reaction conditions further oxidation of the arylidene acetals takes place in the system leading to the formation of products like iodoester 2 and hydroxy esters 3, 4 and 5. Both unsubstituted (1a) and substituted arylidene acetal with electron releasing group (1d) give high yield of iodoester 2 (70-80%) whereas the arylidene acetal substituted with an electron withdrawing group such as NO2 (1b) gives a low yield of the corresponding iodoester (2b, 25%).
- Borah, Ruli,Kalita, Dipok J.,Sarma, Jadab C.
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p. 1032 - 1038
(2007/10/03)
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- A simple and versatile method for the synthesis of acetals from aldehydes and ketones using bismuth triflate
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Acetals are obtained in good yields by treatment of aldehydes and ketones with trialkyl orthoformate and the corresponding alcohol in the presence of 0.1 mol % Bi(OTf)3·4H2O. A simple procedure for the formation of acetals of diaryl ketones has also been developed. The conversion of carbonyl compounds to the corresponding 1,3-dioxolane using ethylene glycol is also catalyzed by Bi(OTf)3· 4H2O (1 mol %). Two methods, both of which avoid the use of benzene, have been developed.
- Leonard, Nicholas M.,Oswald, Matthew C.,Freiberg, Derek A.,Nattier, Bryce A.,Smith, Russell C.,Mohan, Ram S.
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p. 5202 - 5207
(2007/10/03)
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- Highly efficient and chemoselective interchange of 1,3-oxathioacetals and dithioacetals to acetals promoted by N-halosuccinimide
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Highly efficient interconversion of a range of 1,3-oxathiolanes, 1,3-dithiolanes and 1,3-dithianes to their acetals at ambient temperature using N-bromosuccinimide or N-chlorosuccinimide and different types of alcohols and diols was investigated.
- Karimi, Babak,Seradj, Hassan,Maleki, Jafar
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p. 4513 - 4516
(2007/10/03)
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- An efficient route to biaryls from aryl halides catalysed by subnanometrical 2,2′-bipyridine liganded Ni-Al clusters
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It has been shown that the new 2,2′-bipyridine liganded Ni-Al bimetallic clusters are efficient in promoting the catalytic homocoupling of (het)aryl chlorides and bromides.
- Massicot, Fabien,Schneider, Rapha?l,Fort, Yves,Illy-Cherrey, Sandra,Tillement, Olivier
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p. 531 - 536
(2007/10/03)
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- Eco-friendly Pt-Mo/ZrO2 solid acid catalyst for selective protection of carbonyl compounds
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An easy method for protection of carbonyl compounds has been carried out in excellent yields under catalysis of Pt-Mo/ZrO2 in toluene at 383 K.
- Reddy,Reddy,Giridhar
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p. 1819 - 1823
(2007/10/03)
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- Microwave-assisted rapid ketalization/acetalization of aromatic aldehydes and ketones in aqueous media
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Aromatic aldehydes and ketones are readily acetalized or ketalized under microwave irradiation in the presence of water as a solvent.
- Pourjavadi, Ali,Mirjalili, Bibi Fatemeh
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p. 562 - 563
(2007/10/03)
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- Naphthalene-catalysed lithiation of 2-(chlorophenyl)-1,3-dioxolanes: Generation of formyl- and acetyl-phenyllithium equivalents [1]
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The reaction of 2-(chlorophenyl)-1,3-dioxolanes 1 with an excess of lithium powder and a catalytic amount of naphthalene (5 mol %) in the presence of different carbonyl compounds [(t)BuCHO, Et2CO, (CH2)5CO, PhCOMe] as elec
- Huerta, Fernando F.,Gomez, Cecilia,Yus, Miguel
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p. 4043 - 4050
(2007/10/03)
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- Cadmium iodide catalyzed and efficient synthesis of acetals under microwave irradiations
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A new selective method of acetalization of aldehydes and ketones with 1,2-diols, 1,3-diols or alcohols mediated by cadmium iodide under microwave irradiation is achieved in excellent yields.
- Laskar, Dhrubojyoti Dey,Prajapati, Dipak,Sandhu, Jagir S.
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p. 1283 - 1284
(2007/10/03)
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- A new selective catalytic acetalization method promoted by microwave irradiation
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A new selective method of acetalization of aldehydes and cyclic ketones with 1,2-diols or alcohols catalyzed by iodine under microwave irradiation is reported.
- Kalita, Dipok J.,Borah, Ruli,Sarma, Jadab C.
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p. 4573 - 4574
(2007/10/03)
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- Selective Catalytic Transesterification, Transthiolesterification, and Protection of Carbonyl Compounds over Natural Kaolinitic Clay
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Transesterification and transthiolesterification of β-keto esters with variety of alcohols and thiols and selective protection of carbonyl functions with various protecting groups catalyzed by natural kaolinitic clay are described. The clay has been found to be an efficient catalyst in transesterifying long chain alcohols, unsaturated alcohols, and phenols to give their corresponding β-keto esters in high yields. For the first time, transthiolesterification of β-keto esters with a variety of thiols has been achieved under catalytic conditions. Clay also catalyzes selective transesterification of β-keto esters by primary alcohols in the presence of secondary and tertiary alcohols giving corresponding β-keto esters. A systematic study involving the reactivity of different nucleophiles (alcohols, amines, and thiols) toward β-keto esters is also described. Sterically hindered carbonyl groups as well as α,β-unsaturated carbonyl groups underwent protection without the deconjugation of the double bond. Chemoselective protection of aldehydes in the presence of ketones has also been achieved over natural kaolinitic clay.
- Ponde, Datta E.,Deshpande, Vishnu H.,Bulbule, Vivek J.,Sudalai, Ammugam,Gajare, Anil S.
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p. 1058 - 1063
(2007/10/03)
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