- Selective Synthesis of Acylated Cross-Benzoins from Acylals and Aldehydes via N-Heterocyclic Carbene Catalysis
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The utility of acylals as building blocks for selective cross-benzoin synthesis was explored in this study. The synthesis of α-acetoxyketones (O-acyl cross-benzoins) was achieved via selective N-heterocyclic carbene-catalyzed cross-benzoin reactions using acylals as aldehyde equivalents. Thus, the combination of ortho-substituted phenyl acylals and aromatic/aliphatic aldehydes as coupling substrates using bicyclic triazolium salts as precatalysts and potassium carbonate as a base in THF at reflux temperature selectively yielded O-acyl cross-benzoins.
- Onodera, Kou,Suzuki, Yumiko,Takashima, Ryo
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supporting information
p. 4197 - 4202
(2021/06/27)
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- Transition-Metal-Free Synthesis of Polyfunctional Triarylmethanes and 1,1-Diarylalkanes by Sequential Cross-Coupling of Benzal Diacetates with Organozinc Reagents
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A variety of functionalized triarylmethane and 1,1-diarylalkane derivatives were prepared via a transition-metal-free, one-pot and two-step procedure, involving the reaction of various benzal diacetates with organozinc reagents. A sequential cross-coupling is enabled by changing the solvent from THF to toluene, and a two-step SN1-type mechanism was proposed and evidenced by experimental studies. The synthetic utility of the method is further demonstrated by the synthesis of several biologically relevant molecules, such as an anti-tuberculosis agent, an anti-breast cancer agent, a precursor of a sphingosine-1-phosphate (S1P) receptor modulator, and a FLAP inhibitor.
- Wei, Baosheng,Ren, Qianyi,Bein, Thomas,Knochel, Paul
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supporting information
p. 10409 - 10414
(2021/03/26)
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- N-Propylsulfamic acid supported onto magnetic Fe3O4 nanoparticles (MNPs-PSA) as a green and reusable heterogeneous nanocatalyst for the chemoselective preparation and deprotection of acylals
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Abstract: N-propylsulfamic acid supported onto magnetic Fe3O4 nanoparticles (MNPs-PSA) was simply synthesized and used as a highly efficient, environmentally friendly, and chemoselective catalyst for the synthesis of 1,1-diacetates (acylals) from the one-pot condensation reaction of various aromatic aldehydes with acetic anhydride, in high yield of products (86–96%) and short reaction time (20–60?min) under solvent-free conditions at room temperature. In addition to these results, we further studied the possibility of deprotection of the resulting acylals into benzaldehyde derivatives in this catalytic system by the addition of water. More importantly, noteworthy advantages of this study are non-use of toxic organic solvents and catalysts, simple work-up procedure, short reaction time, high yield of products, and recovery and reusability of MNPs-PSA by an external magnet. Graphical Abstract: A simple and highly efficient procedure for the protection of various aldehydes with acetic anhydride in the presence of N-propylsulfamic acid supported onto magnetic Fe3O4 nanoparticles (MNPs-PSA) is reported. We further studied the possibility of deprotection of the resulting acylals into benzaldehyde derivatives in this catalytic system by the addition of water as a green solvent. The catalyst was reused several times without loss of its catalytic activity.
- Sajjadifar, Sami,Nasri, Parastoo
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p. 6677 - 6689
(2017/10/06)
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- Microwave-assisted green synthesis of 1,1-diacetates (acylals) using selectfluor as an environmental-friendly catalyst under solvent-free conditions
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An efficient and simple procedure has been developed for the acetylation of aldehyde by selectfluor [1-(chloromethyl)-4-fluoro-1,4-diazoniabicyclo[2,2,2]octane bis(tetrafluoroborate)] as a chemoselective and environmentally friendly catalyst under solvent-free conditions or microwave irradiation. The application of microwave irradiation improved the yields and reduced the reaction times. In this study, selective conversion of aldehydes was observed in the presence of ketones, and the deprotection of 1,1-diacetates has also been achieved using selectfluor in water as green solvent in reflux conditions. The methodology provides synergy of microwave irradiation which offers several advantages such the simple work-up procedure, short reaction time, excellent yields and environmentally benign procedure.
- Rezayati, Sobhan,Hajinasiri, Rahimeh,Erfani, Zahra
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p. 2567 - 2576
(2016/03/16)
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- Solvent-free Chemoselective Synthesis of 1,1-diacetates Catalyzed by Iron Zirconium Phosphate
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In the present study, a mild, rapid, and efficient method for the protection of aldehydes with acetic anhydride (AA) in the presence of iron zirconium phosphate (ZPFe), at room temperature is reported. Selective conversion of aldehydes was observed in the presence of ketones. Under these conditions, different aldehydes bearing electron-withdrawing and electron-donating substituents were reacted with AA and the corresponding 1,1-diacetates (acylals) were obtained in high to excellent yields. The steric and electronic properties of the different substrates had a significant influence on the reaction conditions. Also, the deprotection of 1,1-diacetates has been achieved using this catalyst in water. The catalyst was characterized by several physico-chemical techniques. It was recovered easily from the reaction mixture, regenerated, and reused at least 7 times without significant loss in catalytic activity. This protocol has the advantages of easy availability, stability, reusability of the eco-friendly catalyst, chemoselectivity, simple experimental and work-up procedure, solvent-free conditions and only a stoichiometric amount of AA is needed.
- Karimi, Hirbod
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p. 1000 - 1010
(2015/12/01)
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- Zinc zirconium phosphate as an efficient catalyst for chemoselective synthesis of 1,1-diacetates under solvent-free conditions
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In the present study, a mild, rapid, and efficient method for the protection of aldehydes with acetic anhydride (AA) in the presence of zinc zirconium phosphate (ZPZn) as a nano catalyst, at room temperature is reported. Selective conversion of aldehydes was observed in the presence of ketones. Under these conditions, different aldehydes bearing electron-withdrawing and electron-donating substituents were reacted with AA and the corresponding 1,1-diacetates (acylals) were obtained in high to excellent yields. The steric and electronic properties of the different substrates had a significant influence on the reaction conditions. Also, the deprotection of 1,1-diacetates has been achieved using this catalyst in water. This nanocatalyst was characterized by several physico-chemical techniques. It was recovered easily from the reaction mixture, regenerated and reused at least 7 times without significant loss in catalytic activity. This protocol has the advantages of easy availability, stability, reusability of the eco-friendliness, chemoselectivity, simple experimental and work-up procedure, solvent-free conditions and usage of only a stoichiometric amount of AA.
- Hajipour, Abdol R,Karimi, Hirbod
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p. 1945 - 1955
(2015/12/30)
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- Green procedures for the chemoselective synthesis of acylals and their cleavage promoted by recoverable sulfonic acid based nanoporous carbon (CMK-5-SO3H)
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A selective synthesis of gem-diacetates from the reaction of aldehydes and acetic anhydride in the presence of recyclable nanoporous solid sulfonic acid (CMK-5-SO3H) under solvent-free reaction conditions is reported. The catalyst was also found to be highly active for deprotection of resulting acylals in water. [Figure not available: see fulltext.]
- Zareyee, Daryoush,Mirzajanzadeh, Ehsan,Khalilzadeh, Mohammad Ali
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p. 1229 - 1234
(2015/10/06)
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- Poly(4-vinylpyridinium) perchlorate as an efficient solid acid catalyst for the chemoselective preparation of 1,1-diacetates from aldehydes under solvent-free conditions
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Poly(4-vinylpyridinium) perchlorate has been used as a supported, recyclable, environmentally-benign catalyst for the formation of acylals from aliphatic and aromatic aldehydes in good to excellent yields under solvent-free conditions. Notably, the reaction conditions were tolerant of ketones. This methodology offers several distinct advantages, including its operational simplicity and high product yield, as well as being green in terms of avoiding the use of toxic catalysts and solvents. Furthermore, the catalyst can be recovered and reused several times without any loss in its activity.
- Khaligh, Nader Ghaffari
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p. 329 - 334
(2014/04/03)
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- Functionalized Poly(Amidoamine) Dendrimer as a Strong Ionic Br?nsted Acid Organocatalyst for Protection/Deprotection of Aldehydes
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Poly(amidoamine) dendrimer (PAMAM) was successfully functionalized by chlorosulfonic acid to form an strong ionic acid catalyst. The resulting polymeric catalyst was shown to be an efficient catalyst for the synthesis of 1,1-diacetyl from aldehydes under free solvent conditions at room temperature. Also, the deprotection of the resulting aldehydes was investigated under catalytic conditions. The Hammett acidity function of catalyst showed that catalyst is a strong Br?nsted acid. Due to the multi-functional nature of PAMAM, the catalyst has high loading level of acidic protons.
- Pourjavadi, Ali,Hosseini, Seyed Hassan
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p. 1794 - 1801
(2015/10/29)
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- Ultrasound assisted the chemoselective 1,1-diacetate protection and deprotection of aldehydes catalyzed by poly(4-vinylpyridinium)hydrogen sulfate salt as a eco-benign, efficient and reusable solid acid catalyst
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Poly(4-vinylpyridinium) hydrogen sulfate solid acid was found to be efficient catalyst for preparation of 1,1-diacetate using ultrasound irradiation at ambient temperature and neat condition. Deprotection of the resulting 1,1-diacetates were achieved using the same catalyst in methanol solvent under ultrasound irradiation at room temperature. This new method consistently has the advantage of excellent yields and short reaction times. Utilization of solvent free, simple reaction conditions, isolation, and purification makes this manipulation very interesting from an economic and environmental perspective. Further, the catalyst can be reused and recovered for several times.
- Khaligh, Nader Ghaffari,Shirini, Farhad
-
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- A succinimide-N-sulfonic acid catalyst for acetylation reactions in absence of a solvent
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A small amount of succinimide-N-sulfonic acid efficiently catalyzed the acetylation of a variety alcohols, phenols, thiols, amines and aldehydes with acetic anhydride at room temperature under solvent free conditions. This catalyst has the advantages of excellent yields and short reaction times and the reaction can be carried out on a large scale, which makes it potentially useful for industrial applications.
- Shirini, Farhad,Khaligh, Nader Ghaffari
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p. 695 - 703
(2013/08/25)
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- A rapid, convenient and chemoselective synthesis of acylals from aldehydes catalyzed by reusable nano-ordered MCM-41-SO3H
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Acylals were prepared by direct condensation of aldehydes with acetic anhydride using nano-ordered MCM-41-SO3H as a heterogeneous catalyst under solvent-free conditions at room temperature in a very short reaction time and excellent yields. The catalyst is recyclable, non-toxic, neither air nor moisture sensitive, and easy to handle. High chemoselectivity toward aldehydes in the presence of ketones is another advantage of the present method which provides selective protection of aldehydes in their mixtures with ketones.
- Tourani, Hesam,Naimi-Jamal, Mohammad Reza,Dekamin, Mohammad Ghorban,Amirnejad, Meysam
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p. 1072 - 1076
(2013/02/22)
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- Rice husk supported FeCl3 nanoparticles as an efficient and reusable catalyst for the chemoselective 1,1-diacetate protection and deprotection of aldehydes
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1,1-Diacetates were produced from a variety of aromatic aldehydes using rice husk supported FeCl3 nanoparticles as a catalyst. The procedure generally resulted in good yields (98%) of aromatic aldehydes including those carrying electron donating- or withdrawing-substituents. Deprotection of the resulting 1,1-diacetates was also achieved using the same catalyst in ethanol. This new method consistently has the advantages of excellent yields and relatively short reaction times. Further, the catalyst can be reused and recovered for several times.
- Shirini, Farhad,Akbari-Dadamahaleh, Somayeh,Mohammad-Khah, Ali
-
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- Conjugate polymer-supported acid catalysts: An efficient and reusable catalyst for the synthesis of geminal diacetates (acylals) under solvent-free conditions
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A comparative study on the catalytic activity of conducting polyaniline (PANI), polypyrrole (PPY), and poly-(3,4-ethylenedioxythiophene) (PEDOT) salts as solid acid catalysts for the synthesis of 1,1-diacetates (acylals) under solvent-free conditions has been presented. Use of the polypyrrole and poly-(3,4-ethylenedioxythiophene) salts as solid acid catalysts is reported for the first time. Preparation, recovery, and reusability of the catalysts were found to be good. Copyright Taylor & Francis Group, LLC.
- Nabid, Mohammad Reza,Rezaei, Seyed Jamal Tabatabaei,Abedi, Mahvash
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experimental part
p. 191 - 199
(2011/03/18)
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- Chemoselective synthesis of 1,1-diacetates from aldehydes using anhydrous cobalt(II) bromide under solvent-free conditions
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A mild and efficient method has been developed for the chemoselective preparation of 1,1-diacetates (acylals) from aldehydes catalyzed in the presence of a catalytic amount (0.1mmol) of anhydrous cobalt(II) bromide under solvent-free conditions. The remarkable selectivity under mild and neutral conditions, excellent yields, short reaction time, and easily available and inexpensive catalyst are important features of this method.
- Meshram, Gangadhar A.,Patil, Vishvanath D.
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experimental part
p. 442 - 449
(2010/04/02)
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- Silica phosphoric acid: An efficient and recyclable catalyst for the solvent-free synthesis of acylals and their deprotection in MeOH
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Silica phosphoric acid was used as an efficient, mild, and recyclable solid catalyst for the synthesis of acylals from various structurally diverse aldehydes and acetic anhydride under solvent-free conditions. The acylation of aldehydes was highly chemoselective, and no ketone was acylated, which provided a method for the synthesis of acylals from aldehydes in the presence of ketones. Silica phosphoric acid-catalyzed deprotection of acylals to the corresponding aldehydes in MeOH has also been developed with excellent yield. The deprotection of the acylals of aromatic aldehydes took priority over those of aliphatic aldehydes. Copyright Taylor & Francis Group, LLC.
- Zhang, Fuyi,Liu, Hong,Zhang, Qing-Ju,Zhao, Yu-Fen,Yang, Feng-Ling
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experimental part
p. 3240 - 3250
(2010/12/24)
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- RuCl3·xH2O: A new efficient catalyst for facile preparation of 1,1-diacetates from aldehydes
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An efficient, facile preparation of aldehyde 1,1-diacetates (acylals) in excellent yields catalyzed by RuCl3·xH2O is described. Ketones do not react under these conditions. Copyright Taylor & Francis Group, LLC.
- Saini, Anil,Kumar, Sanjay,Sandhu, Jagir S.
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p. 106 - 113
(2008/03/14)
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- Thallium(III) chloride: A mild and efficient catalyst for acylation of alcohols, phenols and thiols, and for geminal diacylation of aldehydes under solvent-free conditions
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Thallium(III) chloride is a simple and efficient catalyst for acylation of alcohols, phenols and thiols. It is also very effective for geminal diacylation of aldehydes. The acylation reaction using acetic anhydride proceeds in excellent yield in the presence of catalytic amounts of thallium(III) chloride (1 mol%) at room temperature within relatively short reaction times (20 min). Structurally diverse alcohols, phenols, thiols and aldehydes undergo acylation under solvent-free conditions.
- Kadam, Santosh T.,Kim, Sung Soo
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experimental part
p. 3307 - 3313
(2009/05/07)
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- (NH4)3PW12O40 as an efficient and reusable catalyst for the synthesis and deprotection of 1,1-diacetates
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An efficient method for the synthesis of 1,1-diacetates (acylals) from different aldehydes in the presence of (NH4)3PW12O40 and acetic anhydride under solvent-free conditions at ambient temperature is achieved. Selective conversion of aldehydes was observed in the presence of ketones. The deprotection of acylals has also been achieved using (NH4)3PW12O40 in methanol. The catalyst was found to possess good activity and considerable level of reusability. Copyright Taylor & Francis Group, LLC.
- Satam, Jitendra R.,Jayaram, Radha V.
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p. 595 - 602
(2008/04/12)
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- A versatile and practical synthesis of 1,1-diacetates from aldehydes catalyzed by cyanuric chloride
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Structurally diverse aldehydes are successfully converted into 1,1-diacetates with acetic anhydride using cyanuric chloride as a mild, convenient and inexpensive catalyst under solvent-free conditions. The noteworthy features of the present system are shorter reaction times, and mild and solvent-free conditions. Furthermore, it offers chemoselective protection of aldehydes.
- Bandgar, Babasaheb P.,Joshi, Neeta S.,Kamble, Vinod T.
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p. 489 - 492
(2008/02/11)
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- A facile and efficient conversion of aldehydes into 1,1-diacetates (acylals) using iron(III) fluoride as a novel catalyst
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Aldehydes are smoothly converted into the corresponding 1,1-diacetates (acylals) in high yields in the presence of a catalytic amount (0.1 mol-%) of iron(III) fluoride at room temperature. The noteworthy features of the present system are shorter reaction times, chemoselective protection of aldehydes, and solvent-free conditions. The procedure is especially useful for large-scale syntheses as the catalyst is highly effective from the view of activity, selectivity, reusability, and economy in the preparation of 1,1-diacetates (acylals). CSIRO 2007.
- Kamble,Tayade,Davane,Kadam
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p. 590 - 594
(2008/03/11)
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- PEG-supported sulfonic acid as an efficient and recyclable catalyst for the synthesis of 1,1-diacetates under solvent-free conditions
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An operationally simple, efficient, and environmentally benign synthesis of 1,1-diacetates in good yields by reaction of different aldehydes with acetic anhydride in the presence of PEG-supported sulfonic acid under solvent-free conditions is described. C
- Wang, Qiu-Ying,Sheng, Shou-Ri,Wei, Mei-Hong,Xie, Zhong-Li,Liu, Xiao-Ling
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p. 1019 - 1026
(2007/10/03)
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- P2O5/Al2O3 as an efficient heterogeneous catalyst for chemoselective synthesis of 1,1-diacetates under solvent-free conditions
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An efficient and chemoselective method for the preparation of acylals from different aldehydes using P2O5/Al2O3 and acetic anhydride under solvent-free conditions.
- Hajipour, Abdol R.,Zarei, Amin,Ruoho, Arnold E.
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p. 2881 - 2884
(2007/10/03)
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- Chemoselective synthesis of 1,1-diacetates from aldehydes in the presence of Al(HSO4)3 under mild solvent-free conditions
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A novel efficient procedure has been developed for the preparation of acylals in high yields by reaction of the corresponding aldehydes with acetic anhydride in the presence of Al(HSO4)3 as catalyst under mild (room temperature) solvent-free conditions.
- Mirjalili,Zolfigol,Bamoniri,Amrollahi,Sheikhan
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p. 852 - 854
(2008/03/11)
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- Solid silica sulfuric acid (SSA) as a novel and efficient catalyst for acetylation of aldehydes and sugars
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Acetylation of aldehydes and sugars catalyzed by solid silica sulfuric acid (SSA) is described. In these reactions SSA shows a highly catalytic nature: easy to handle procedure, short reaction time, recycle exploitation, insensitivity to air and moisture, excellent isolated yields. The catalyst could be recycled at least five times.
- Wu, Hui,Shen, Yang,Fan, Li-yan,Wan, Yu,Shi, Da-qing
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p. 7995 - 7998
(2007/10/03)
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- A remarkable HBF4-SiO2-catalyzed synthesis of acylals from aldehydes under solvent-free conditions
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HBF4-SiO2 has been found to be an outstanding catalyst for the protection of carbonyl compounds as acylals under entirely solvent-free conditions. Some of the major advantages of this procedure are high yields, ease of operation, high chemoselectivity, high atom efficiency, and compatibility with other protecting groups. Georg Thieme Verlag Stuttgart.
- Kamble, Vinod T.,Bandgar, Babasaheb P.,Joshi, Neeta S.,Jamode, Vasant S.
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p. 2719 - 2722
(2008/02/11)
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- Silica sulfuric acid as an efficient heterogeneous catalyst for the synthesis of 1,1-diacetates under solvent-free conditions
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An efficient method for the preparation of acylals from different aldehydes in the presence of silica sulfuric acid and acetic anhydride under solvent-free conditions is reported. Georg Thieme Verlag Stuttgart.
- Hajipour, Abdol R.,Zarei, Amin,Khazdooz, Leila,Mirjalili, Bi Bi F.,Sheikhan, Nafise,Zahmatkesh, Saeed,Ruoho, Arnold E.
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p. 3644 - 3648
(2007/10/03)
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- Copper(II) tetrafluoroborate-catalyzed formation of aldehyde-1,1-diacetates
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Aldehyde 1,1-diacetates are farmed in excellent yields from aldehydes and acetic anhydride under solvent-free conditions at room temperature in short times in the presence of a catalytic amount of copper(II) tetrafluoroborate hydrate.
- Chakraborti, Asit K.,Thilagavathi, Ramasamy,Kumar, Raj
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p. 831 - 833
(2007/10/03)
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- Aluminum dodecatungstophosphate (AlPW12O40) as an efficient heterogeneous inorganic catalyst for the chemoselective synthesis of geminal diacetates (acylals) under solvent-free conditions
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An efficient and chemoselective preparation of acylals from structurally different aldehydes in the presence of AlPW12O40 and acetic anhydride was achieved easily in high yields at room temperature under solvent-free conditions.
- Firouzabadi, Habib,Iranpoor, Nasser,Nowrouzi, Farhad,Amani, Kamal
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p. 3951 - 3954
(2007/10/03)
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- Reductive esterification of aromatic aldehydes using Zn/Ac 2O/imidazole or Zn/Yb(OTf)3/(RCO)2O system
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Benzaldehydes are reduced by metallic zinc in the presence of Ac 2O and imidazole, giving the corresponding benzyl acetates in good yields. Reductive esterification of aromatic aldehydes is also carried out via gem-diacetoxy compounds. Carbonyl compounds are readily converted to the gem-diacyloxy compounds in excellent yields on treatment with 2molar amounts of acid anhydride and 10mol% of Yb(OTf)3 in MeCN at room temperature. Thus-formed diacyloxy compounds derived from aromatic aldehydes are reduced in situ by metallic zinc to afford the corresponding esters.
- Hirao, Toshikazu,Santhitikul, Sirida,Takeuchi, Hiroki,Ogawa, Akiya,Sakurai, Hidehiro
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p. 10147 - 10152
(2007/10/03)
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- Indium trichloride catalyzed chemoselective conversion of aldehydes to gem-diacetates
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Aldehydes are chemoselectively converted into the corresponding gem-diacetates at ambient temperature in high to quantitative yields using a catalytic amount of indium (III) chloride. The deprotection of the resulting gem-diacetates is achieved using the same catalyst in the presence of water.
- Yadav,Subba Reddy,Srinivas, Ch.
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p. 1175 - 1180
(2007/10/03)
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- Indium trichloride catalyzed chemoselective conversion of aldehydes to gem-diacetates
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Aldehydes are chemoselectively converted into the corresponding gem-diacetates at ambient temperature in high to quantitative yields using a catalytic amount of indium(III) chloride. The deprotection of the resulting gem-diacetates is achieved using the s
- Yadav,Reddy, B. V. Subba,Srinivas
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p. 2169 - 2174
(2007/10/03)
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- Pharmaceutical compositions
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Pharmaceutical compositions which are useful for the treatment of cancer or illnesses which arise due to an abnormally elevated cell proliferation comprise acyl derivatives of aromatic aldehydes, especially arylidene diesters and α-alkoxyarylidene esters of general formula (I). STR1
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- Efficient and selective protection of aldehydes as geminal diacetates using LiBr
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A variety of aldehydes react with acetic anhydride in presence of lithium bromide at room temperature to afford the corresponding 1,1-diacetates in quantitative yields within a few hours of reaction time.
- Kumar, H. M. Sampath,Reddy, B. V. Subba,Reddy, P. Thirupathi,Yadav, J. S.
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- Solvent free synthesis and deprotection of 1,1-diacetates over a commercially available zeolite Y as a reusable catalyst
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Chemoselective synthesis and deprotection of 1,1-diacetates have been performed in good yields and in the absence of any solvent by zeolite HSZ- 360 as a new reusable catalyst.
- Ballini, Roberto,Bordoni, Marco,Bosica, Giovanna,Maggi, Raimondo,Sartori, Giovanni
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p. 7587 - 7590
(2007/10/03)
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- Sulfated Zirconia: an Efficient Catalyst for the Synthesis of 1,1-Diacetates from Aldehydes and Ketones
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A variety of aldehydes and ketones react with acetic anhydride in the presence of catalytic amounts of solid sulfated zirconia to afford the corresponding 1,1-diacetates in excellent yields.
- Raju, Satya V. N.
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-