- Preparation of silica-bonded propyl-diethylene-triamine-N-sulfamic acid as a recyclable catalyst for chemoselective synthesis of 1,1-diacetates
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A simple and efficient procedure for the preparation of silica-bonded propyl-diethylene-triamine-N-sulfamic acid (SPDTSA) by reaction of 3-diethylenetriamine-propylsilica (DTPS) and chlorosulfonic acid in chloroform is described. Silica-bonded propyl-diethylene-triamine-N-sulfamic acid is employed as a recyclable catalyst for the synthesis of 1,1-diacetates from aromatic aldehydes and acetic anhydride under mild and solvent-free conditions at room temperature. Catalyst could be recycled for several times without any additional treatment.
- Nouri Sefat, Maryam,Deris, Abdolah,Niknam, Khodabakhsh
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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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- 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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- Formation of benzylidenes-diacetates catalyzed by activated zeolite "LZY-562" and clay (K10/ZnCl2): An unexpected functional selectivity
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Activated zeolites LZY-562 and clay montmorillonite K10 at room temperature without solvent catalyzes the synthesis of benzylidenesdiacetates from carbonyl compounds. A chemoselectivity was observed between aldehydes and ketones, between the different aldehydes and ketones as well.
- Dokari,Hammadi,Benferrah,Rachedi
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p. 1973 - 1976
(2015/12/01)
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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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- Sulfonated rice husk ash (RHA-SO3H): A highly powerful and efficient solid acid catalyst for the chemoselective preparation and deprotection of 1,1-diacetates
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Rice husk ash (RHA), as a source of amorphous silica, was treated with chlorosulfonic acid and sulfonated rice husk ash (RHA-SO3H) as a highly powerful solid acid catalyst was obtained and characterized with a variety of techniques including IR, TGA, SEM, XRD, pH analysis, Hammett acidity function and BET method. This solid acid showed excellent catalytic activity for the protection and deprotection of aldehydes with Ac2O at room temperature under solvent free conditions. The procedure gave the products in excellent yields in very short reaction times and good to high yields. Also this catalyst can be reused for several times without loss of its catalytic activity.
- Shirini, Farhad,Mamaghani, Manouchehr,Seddighi, Mohadeseh
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- Introduction of N-sulfonic acid poly(4-vinylpyridinum) chloride as an efficient and reusable catalyst for the chemoselective 1,1-diacetate protection and deprotection of aldehydes
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N-sulfonic acid poly(4-vinylpyridinium) chloride is easily prepared by the reaction of poly(4-vinylpyridine) with neat chlorosulfonic acid. This reagent can be used as an efficient catalyst for the preparation of 1,1-diacetates at room temperature and neat condition. Deprotection of the resulting 1,1-diacetates can also be achieved using the same catalyst in methanol. This new method consistently has the advantages of excellent yields and short reaction times. Further, the catalyst can be reused and recovered for several times.
- Shirini, Farhad,Jolodar, Omid Goli
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experimental part
p. 61 - 69
(2012/04/17)
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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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- Silica-bonded S-sulfonic acid as a recyclable catalyst for chemoselective synthesis of 1,1-diacetates
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A simple and efficient procedure for the preparation of silica-bonded S-sulfonic acid (SBSSA) by reaction of 3-mercaptopropylsilica (MPS) and chlorosulfonic acid in chloroform is described. This solid acid is employed as a recyclable catalyst for the synthesis of 1,1-diacetates from aromatic aldehydes and acetic anhydride under mild and solvent-free conditions at room temperature.
- Niknam, Khodabakhsh,Saberi, Dariush,Sefat, Maryam Nouri
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scheme or table
p. 4058 - 4062
(2009/10/11)
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- Reinvestigation of the mechanism of gem-diacylation: Chemoselective conversion of aldehydes to various gem-diacylates and their cleavage under acidic and basic conditions
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The mechanism of gem-diacylate formation has been studied extensively using tetrabutylammonium tribromide (TBATB) as the catalyst. The reaction proceeds by a nucleophilic attack of an anhydride on an aldehydic carbonyl group, nucleophilic attack of the hemiacylate intermediate on a second molecule of the anhydride, followed by an intermolecular attack of a second acetate group to regenerate the anhydride. gem-Diacylates of various aliphatic and aromatic aldehydes were obtained directly from the reaction of a variety of aliphatic and aromatic acid anhydrides in the presence of a catalytic quantity of tetrabutylammonium tribromide (TBATB) under solvent-free conditions. A significant electronic effect was observed during its formation as well as deprotection to the corresponding aldehyde. Chemoselective gem-diacylation of the aromatic aldehyde containing an electron-donating group has been achieved in the presence of an aldehyde containing an electron-withdrawing group. Deprotection of the gem-diacylate to the parent carbonyl compound can be accomplished in methanol in presence of the same catalyst. Here again, chemoselective deprotection of the gem-diacylate of a substrate containing an electron-donating group has been achieved in the presence of a substrate containing an electron-withdrawing group. Both the acid and base stability order of the various gem-diacylates examined follow a similar order. The stability order determined from the present study is: gem-dibenzoate > gem-dipivalate > gem-diisobutyrate > gem-diacetate > gem-dipropionate. All the gem-diacylals are more stable under basic conditions than acidic condition. No correlation was found between the stability order and the pKa's of the corresponding acids; rather, the stability order is directly related to the steric crowding around the carbonyl carbon. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.
- Kavala, Veerababurao,Patel, Bhisma K.
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p. 441 - 451
(2007/10/03)
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- An efficient method for diacetylation of aldehydes
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Cu(OTf)2 was found to be an efficient catalyst for acylation reaction of aldehydes with acetic anhydride in CH2Cl2.
- Chandra, Kusum Lata,Saravanan,Singh, Vinod K.
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p. 359 - 360
(2007/10/03)
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- Microwave induced synthesis of geminal diacetates from aldehydes using envirocat EPZ10 without solvent
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A simple, efficient, and environmentally friendly synthesis of geminal diacetates using Envirocat EPZ10 under microwave activation and solvent-free conditions is described. Easy separation and recyclability of the catalyst, high reaction rates, high yields, and easy work-up are important advantages of this method.
- Bandgar, Babasaheb P.,Makone, Sangita S.,Kulkarni, Sulakshana R.
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p. 417 - 420
(2007/10/03)
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