cas 619-90-9, ACETIC ACID 4-NITROBENZYL ESTER

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Acylated oleanane-type triterpene saponins with acceleration of gastrointestinal transit and inhibitory effect on pancreatic lipase from flower buds of Chinese tea plant (Camellia sinensis)
The MeOH extract and its BuOH-soluble fraction (crude saponin fraction) from the flower buds of Chinese tea plant (Camellia sinensis (L.) O. Kuntze; Fujian Province) were found to exhibit accelerating effects on gastrointestinal transit in mice and inhibi
Yoshikawa, Masayuki,Sugimoto, Sachiko,Kato, Yasuyo,Nakamura, Seikou,Wang, Tao,Yamashita, Chihiro,Matsuda, Hisashi
p. 903 - 915
(2009)
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An efficient, economical and eco-friendly acylation of alcohols and amines by alum doped nanopolyaniline under solvent free condition
We report acylation of alcohols and amines employing acetic acid as an acylating agent in solvent free condition by using alum doped nanopolyaniline (NDPANI) as a catalyst. This environmentally benign method does not use corrosive acid anhydrides and acid chlorides for acylation and does not produce waste product. Also, a non-toxic potash alum was used for doping of polyaniline rather than corrosive acids. The reaction conditions represent an advance over established method not only in omitting the need for expensive catalysts or solvents but also in shortening the reaction time significantly. The advantages of this catalyst are non-hazardous, cheap, reusable, easy to prepare and handling.
Behera, Satyaranjan,Patra, Braja N.
(2021/08/06)

Synthesis, Characterisation, and Determination of Physical Properties of New Two-Protonic Acid Ionic Liquid and its Catalytic Application in the Esterification
A new ionic liquid was synthesised, and its chemical structure was elucidated by FT-IR, 1D NMR, 2D NMR, and mass analyses. Some physical properties, thermal behaviour, and thermal stability of this ionic liquid were investigated. The formation of a two-protonic acid salt namely 4,4′-trimethylene-N,N′-dipiperidinium sulfate instead of 4,4′-trimethylene-N,N′-dipiperidinium hydrogensulfate was evidenced by NMR analyses. The catalytic activity of this ionic liquid was demonstrated in the esterification reaction of n-butanol and glacial acetic acid under different conditions. The desired acetate was obtained in 62-88 % yield without using a Dean-Stark apparatus under optimal conditions of 10 mol-% of the ionic liquid, an alcohol to glacial acetic acid mole ratio of 1.3: 1.0, a temperature of 75-100°C, and a reaction time of 4 h. α-Tocopherol (α-TCP), a highly efficient form of vitamin E, was also treated with glacial acetic acid in the presence of the ionic liquid, and O-acetyl-α-tocopherol (Ac-TCP) was obtained in 88.4 % yield. The separation of esters was conducted during workup without the utilisation of high-cost column chromatography. The residue and ionic liquid were used in subsequent runs after the extraction of desired products. The ionic liquid exhibited high catalytic activity even after five runs with no significant change in its chemical structure and catalytic efficiency.
Shahnavaz, Zohreh,Zaharani, Lia,Khaligh, Nader Ghaffari,Mihankhah, Taraneh,Johan, Mohd Rafie
p. 165 - 172
(2020/10/26)

Recyclable DMAP-Functionalized polymeric nanoreactors for highly efficient acylation of alcohols in aqueous systems
Fabrication of highly efficient and recyclable nanoreactors via macromolecular self-assembly represents a promising strategy for green organic transformation. In this study, small-molecule catalysts 4-(N,N-dimethylamino)pyridine (DMAP) functionalized nanoreactors were constructed by self-assembly of amphiphilic block copolymers with DMAP moieties in the hydrophobic block, leading to heterogeneous catalysts with excellent dispersity in water. The key preparation route included reversible addition-fragmentation chain transfer (RAFT) polymerization of 2-(N-methyl-N-(4-pyridyl)amino)ethyl methacrylate (MAPMA) and methyl methacrylate (MMA) using poly (oligomeric (ethylene glycol) methyl ether methacrylate) (POEGMA) as a hydrophilic macromoleculer RAFT reagent. The characterization by dynamic light scattering (DLS) and transmission electron microscopy (TEM) shows that the nanoreactors possess a core-shell nanostructure with the diameter of around 110 nm. The resulting polymeric nanoreactors showed excellent catalytic activity for acylation of alcohols in water. High conversion of a variety of alcohol (>99%) and excellent product selectivity were achieved. The high catalytic efficiency of the nanoreactors may be attributed to the enhancement of the interaction between the reactant and the catalyst in the confined hydrophobic space, which simulates how enzymes usually work. Moreover, the catalyst could be easily recovered by thermos-responsive separation and reused with high activity for more than 5 cycles. This study presents an efficient approach to achieve green catalytic reactions which are normally incompatible to aqueous conditions, potentially applicable to other catalytic systems such as metal-mediated organic transformations.
Qiu, Jiaqi,Meng, Fuliang,Wang, Maolin,Huang, Jinjin,Wang, Chengzhan,Li, Xiao,Yang, Guang,Hua, Zan,Chen, Tao
(2021/03/30)

Facile construction of thermo-responsive Pickering emulsion for esterification reaction in phase transfer catalysis system
In this paper, a thermo-responsive Pickering emulsion (PE) is constructed for the esterification reaction in the phase transfer catalysis (PTC) system. Silica nanoparticle modified by alkyl polyoxyethylene ether and tetrabutylammonium bromide (TBAB) is the highly efficient thermo-responsive Pickering emulsifier to stabilize the diisopropyl ketone-in-water emulsion. PEs can keep stable at room temperature for 3 days and demulsify only in the condition of elevated temperature and agitation, which causes the easy product separation and aqueous phase recycling. The adsorption of TBA+ and nonionic surfactant via electrostatic interaction and hydrogen bonding, respectively, can increase the hydrophobicity and the emulsifying capacity of silica nanoparticle. The ion-pair of TBA+ and reactant anion is generated and can be transferred into the organic phase, initiating the bond-forming reaction. The modifying effect of polyoxyethylene ether is weakened with the increase of temperature due to the loss of the hydrogen bonding interaction, resulting in the demulsification of PEs. Moreover, the cloud point of polyoxyethylene ether is the temperature for the complete separation of two phases. In this PTC system, the conversion rate for the esterification can reach to 92 % and the aqueous phase can be reused at least 5 times without sacrifice of the catalytic activity, demonstrating the potential application in industry.
Lei, Manjun,Shen, Yifeng,Sun, Jie,Yang, Lei,Yang, Lihui,Zhao, Qiangqiang,Zhao, Xiao
(2020/12/30)

KMnO4-catalyzed chemoselective deprotection of acetate and controllable deacetylation-oxidation in one pot
A novel and efficient protocol for chemoselective deacetylation under ambient conditions was developed using catalytic KMnO4. The stoichiometric use of KMnO4 highlighted the dual role of a heterogeneous oxidant enabling direct access to aromatic aldehydes in one-pot sequential deacetylation-oxidation. The reaction employed an alternative solvent system and allowed the clean transformation of benzyl acetate to sensitive aldehyde in a single step while preventing over-oxidation to acids. Use of inexpensive and readily accessible KMnO4 as an environmentally benign reagent and the ease of the reaction operation were particularly attractive, and enabled the controlled oxidation and facile cleavage of acetate in a preceding step. This journal is
Gurawa, Aakanksha,Kumar, Manoj,Rao, Dodla S.,Kashyap, Sudhir
supporting information
p. 16702 - 16707
(2020/10/27)

4-Imidazol-1-yl-butane-1-sulfonic acid ionic liquid: Synthesis, structural analysis, physical properties and catalytic application as dual solvent-catalyst
4-Imidazol-1-yl-butane-1-sulfonic acid (ImBu-SO3H) has been successfully synthetized and fully characterized by FT-IR and high-resolution NMR spectroscopy (1H, 13C). The “plausible” alternative structures of ImBu-SO3H were discussed on the basis of its NMR data. The ionic liquid showed interesting dual solvent-catalyst property, which was studied experimentally for the acetylation of a variety of functionalized alcohols, phenols, thiols, amines and α-tocopherol (α-CTP) as the most active form of vitamin E with acetic anhydride and which provided good yields within a short reaction time. ImBu-SO3H was successfully recycled by product extraction with an average recovered yield of 82% for 5 subsequent runs. The catalytic activity of the recycled ImBu-SO3H showed almost no loss even after five consecutive runs.
Khaligh, Nader Ghaffari,Mihankhah, Taraneh,Johan, Mohd Rafie,Juan, Joon Ching
p. 866 - 878
(2019/07/12)

Biogenic CuFe2O4 magnetic nanoparticles as a green, reusable and excellent nanocatalyst for acetylation reactions under solvent-free conditions
A convenient green method has been developed for the synthesis of biogenic CuFe2O4 magnetic nanoparticles using tea extracts within a very short reaction time. The prepared nanoparticles with an average size of 8.78 nm have been used as an effective catalyst for the acetylation of various alcohols, phenols and amines in good to excellent yields under solvent-free conditions. The catalyst was characterized by XRD, XPS, VSM, SEM and TEM study. A magnetic study of the fresh and recycled catalyst after the fourth cycle was performed by VSM measurement. The main advantages of this protocol are simple biogenic synthesis of the catalyst, a reusable and heterogeneous catalytic system, and short reaction times with excellent yields.
Chutia, Rituparna,Chetia, Bolin
p. 15200 - 15206
(2018/09/29)

Synthesis and characterization of MCM-41@XA@Ni(II) as versatile and heterogeneous catalyst for efficient oxidation of sulfides and acetylation of alcohols under solvent-free conditions
Herein, Ni(II) immobilized on modified mesoporous silica MCM-41 was designed and synthesized via a facile sequential strategy. The structure of the catalyst was characterized by X-ray diffraction. The thermal property of the as-synthesized materials was studied using thermogravimetric-differential thermal analysis. The average particles size and morphology of MCM-41@XA@Ni(II) were investigated using scanning electron microscopy and transmission electron microscopy. This nanostructure catalyst was effective for the selective oxidation of sulfides and acetylation of alcohols in solvent-free conditions. The easy recyclability of the catalyst and their complete chemoselectivity toward the sulfur group of substrates in the oxidation of sulfides are important “green” attributes of this catalyst.
Nazarzadeh, Somayeh,Ghorbani-Choghamarani, Arash,Tahanpesar, Elham
p. 649 - 659
(2018/01/28)

Nucleophilic Substitutions of Alcohols in High Levels of Catalytic Efficiency
A practical method for the nucleophilic substitution (SN) of alcohols furnishing alkyl chlorides, bromides, and iodides under stereochemical inversion in high catalytic efficacy is introduced. The fusion of diethylcyclopropenone as a simple Lewis base organocatalyst and benzoyl chloride as a reagent allows notable turnover numbers up to 100. Moreover, the use of plain acetyl chloride as a stoichiometric promotor in an invertive SN-type transformation is demonstrated for the first time. The operationally straightforward protocol exhibits high levels of stereoselectivity and scalability and tolerates a variety of functional groups.
Stach, Tanja,Dr?ger, Julia,Huy, Peter H.
supporting information
p. 2980 - 2983
(2018/05/28)

Reusable and efficient polyvinylpolypyrrolidone-supported triflic acid catalyst for acylation of alcohols, phenols, amines, and thiols under solvent-free conditions
Abstract: A triflic acid-functionalized polyvinylpolypyrrolidone was prepared and fully characterized by FT-IR, TGA, and SEM. This super acidic solid catalyst shows high catalytic activity for selective acylation of alcohols, phenols, amines, and thiols with anhydrides under solvent-free conditions at room temperature. In addition, this method features an easy to handle solid super acid catalyst and an operationally simple procedure, affording the desired acylated products in excellent yields. Graphical abstract: [Figure not available: see fulltext.].
Tajbakhsh, Mahgol,Tajbakhsh, Mahmoud,Khaksar, Samad,Gazvini, Helia Janatian,Heidary, Marzieh
p. 1117 - 1122
(2017/05/10)

Ethyl acetate as an acetyl surrogate for the iodine catalyzed acetylation of alcohols
The use of readily available ethyl acetate in the presence of iodine as an alternative acetylating agent is reported. Amines and phenols were unreactive under the examined reaction conditions, indicating that the method is highly chemoselective.
Basumatary, Grace,Bez, Ghanashyam
supporting information
p. 4312 - 4315
(2017/10/13)

Doping of copper (I) oxide onto a solid support as a recyclable catalyst for acetylation of amines/alcohols/phenols and synthesis of trisubstituted imidazole
A study of copper-mediated C-heteroatom especially C-N and C-O bond formations using simpler methodologies has been carried out. In the present work, acetylation of various substrates such as amines, phenols and alcohols; synthesis of 2,4,5-trisubstituted imidazole is done using simple and easily available starting materials. Copper (I) oxide was synthesized in situ by the reduction of Fehling's solution with glucose followed by its anchoring onto different supports like silica, HAP, basic alumina and cellulose. Comparison and contrasts between the reactivity of copper (I) oxide supported onto different supports for these reactions are made. The reactivity of copper (I) oxide seems to be largely dependent on the nature of support and the most active catalyst for a particular reaction was further characterized by different spectroscopic techniques such as FTIR, XRD, TGA, XPS, SEM, TEM and AAS. The catalysts were found to be stable, easily recyclable without any significant loss in activity. Graphical abstract: Applications of solid supported copper (I) oxides (where solid support is silica, HAP, cellulose and basic alumina) are studied for various organic transformations with special emphasis on C-N and C-O bond formation reactions.[Figure not available: see fulltext.]
Gupta, Manjulla,Gupta, Monika
p. 231 - 241
(2016/01/09)

P4VPy–CuO nanoparticles as a novel and reusable catalyst: application at the protection of alcohols, phenols and amines
P4VPy–CuO nanoparticles were synthesized using ultrasound irradiations. Relevant properties of the synthesized nanoparticles were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy. After identification, the prepared reagent was used for the promotion of different types of protection reactions of alcohols, phenols and amines. Easy workup, short reaction times, excellent yields, relatively low cost and reusability of the catalyst are the striking features of the reported methods.
Shirini, Farhad,Fallah-Shojaei, Abdollah,Abedini, Masoumeh,Samavi, Laleh
p. 1699 - 1712
(2016/07/27)

Highly efficient and recyclable acetylation of phenols and alcohols by nickel zirconium phosphate under solvent-free conditions
Nickel zirconium phosphate nanoparticles have been used as an efficient catalyst for the acetylation of a wide range of alcohols and phenols with acetic anhydride in good to excellent yields under solvent-free conditions. The steric and electronic properties of the different substrates had a significant influence on the reaction conditions required to achieve the acetylation. The catalyst used in the current study was characterized by inductively coupled plasma optical emission spectroscopy, X-ray diffraction, N2 adsorption-desorption, scanning electron microscopy, and transmission electron microscopy. This nanocatalyst could also be recovered and reused at least six times without any discernible decrease in its catalytic activity.
Hajipour, Abdol Reza,Karimi, Hirbod,Kohi, Afshin
p. 55 - 64
(2016/01/09)

Acylated oleanane-type triterpene saponins from the flowers of Bellis perennis show anti-proliferative activities against human digestive tract carcinoma cell lines
Seven oleanane-type triterpene saponin bisdesmosides, perennisaponins N–T (1–7), were newly isolated from a methanol extract of daisy, the flowers of Bellis perennis L. (Asteraceae). The structures were determined based on chemical and physicochemical data and confirmed using previously isolated related compounds as references. The isolates, including 13 previously reported perennisaponins A–M (8–20), exhibited anti-proliferative activities against human digestive tract carcinoma HSC-2, HSC-4, and MKN-45 cells. Among them, perennisaponin O (2, IC50?=?11.2, 14.3, and 6.9?μM, respectively) showed relatively strong activities. The mechanism of action of 2 against HSC-2 was found to involve apoptotic cell death.
Ninomiya, Kiyofumi,Motai, Chiaki,Nishida, Eriko,Kitagawa, Niichiro,Yoshihara, Kazuya,Hayakawa, Takao,Muraoka, Osamu,Li, Xuezheng,Nakamura, Seikou,Yoshikawa, Masayuki,Matsuda, Hisashi,Morikawa, Toshio
p. 435 - 451
(2016/07/16)

Synthesis and characterization of ionic liquid immobilized on magnetic nanoparticles: A recyclable heterogeneous organocatalyst for the acetylation of alcohols
Herein, we describe a simple and efficient procedure for the preparation of 3-((3-(trisilyloxy)propyl)propionamide)-1-methylimidazolium chloride ionic liquid supported on magnetic nanoparticle (TPPA-IL-Fe3O4). The structure of this magnetic ionic liquid is fully characterized by FT-IR, TGA, XRD, VSM, SEM, EDX and DLS techniques. TPPA-IL-Fe3O4 is employed as a catalyst for the acetylation of alcohols with acetic anhydride under mild and heterogeneous conditions at room temperature with good to excellent yields. The magnetic catalyst could be readily separate from the reaction media by simple magnetic decantation, and reused several times without significant loss of its catalytic activity.
Ghorbani-Choghamarani, Arash,Norouzi, Masoomeh
p. 832 - 840
(2015/11/16)

Tetraethylammonium hydrogen carbonate: A cheap, efficient, and recyclable catalyst for transesterification reactions under solvent-free conditions
Tetraethylammonium hydrogen carbonate (TEAHC) was proven to be an efficient catalyst for transesterification reactions in the absence of solvent. The reaction between isopropenyl or ethyl acetate and an alcohol (not efficient in the absence of catalyst) was induced by the presence of TEAHC, which seems to assist the proton transfer from the alcohol to the ester, yielding the corresponding acetate in very good yields in the absence of any solvent. Moreover, the TEAHC can be recycled several times without significant loss in activity.
Chiarotto, Isabella
supporting information
p. 1840 - 1847
(2016/11/18)

Transesterification Reactions Catalyzed by a Recyclable Heterogeneous Zinc/Imidazole Catalyst
We report the development of a universal and recyclable heterogeneous zinc/imidazole catalyst. The catalyst is recoverable through simple filtration and can be reused at least five times, retaining its catalytic activity. Leached zinc species were not responsible for the observed catalysis based on the hot filtration test and ICP-MS analysis. The heterogeneous zinc catalyst also promotes chemoselective transesterification over amidation. (Figure presented.).
Nakatake, Daiki,Yazaki, Ryo,Matsushima, Yoshimasa,Ohshima, Takashi
supporting information
p. 2569 - 2574
(2016/08/16)

Sulfonic acid-functionalized periodic mesoporous organosilicas in esterification and selective acylation reactions
The application of sulfonic acid-functionalized periodic mesoporous organosilicas (PMOs) having either phenyl (1a) or ethyl (1b) bridging groups was investigated in the esterification of a variety of alcohols and fatty acids. It was found that 1b consistently exhibited higher catalytic performance than 1a in the described reaction. In particular, it was proposed that the superior catalytic activity of 1b in esterification of fatty acids with methanol is a result of adequate hydrophobic-hydrophilic surface balance in the ethyl PMO catalyst. In addition, the study of chemoselective acylation of 1,3-butanediol with dodecanoic acid with varied mesoporous silica-supported solid sulfonic acids including both 1a and 1b implies that there is a compromise between the reaction selectivity and the surface physicochemical properties of the employed catalyst. Our results clearly show that the catalyst having high surface hydrophilic nature gives high selectivity toward the formation of mono-acylated products whereas those with relatively high hydrophobic characteristics showed enhanced selectivity toward the formation of di-acylated products.
Karimi, Babak,Mirzaei, Hamid M.,Mobaraki, Akbar,Vali, Hojatollah
p. 3624 - 3631
(2015/07/01)

Microwave-Assisted Catalytic Acetylation of Alcohols by Gold-Nanoparticle-Supported Gadolinium Complex
A gold nanoparticle (AuNP)-supported gadolinium complex (RS-Au-L-Gd) catalyst was prepared through simple chelation of GdCl3 to the surface-bound spacer, 1,4,7-tris(carboxymethyl)-10-(11-mercaptoundecyl)-1,4,7,10-tetraazacyclododecane (HSDO3A). This AuNP-supported Gd complex was found to be a highly effective catalyst for the acetylation of various alcohols and phenol in the presence of acetic anhydride. With a loading of 0.4 mol% of RS-Au-L-Gd, the almost complete transformation can be achieved in 60 s under microwave irradiation conditions. This hybrid catalyst was air stable, water soluble, dissolvable in many organic media, and precipitable. It can be readily recycled more than eight times without any significant loss of its catalytic activity. GRAPHICAL ABSTRACT.
Chang, Tsao-Ching,Yu, Shuchun Joyce
p. 661 - 672
(2015/10/29)

Efficient approach for the chemoselective acetylation of alcohols catalyzed by a novel metal oxide nanocatalyst CuO-ZnO
A new method has been developed for the chemoselective acetylation of alcohols with acetic anhydride in the presence of phenols using a novel, recyclable CuO-ZnO nanocatalyst. The catalyst was synthesized using the co-precipitation method and characterized by N2 adsorption-desorption, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and energy dispersion scanning analyses. Furthermore, this catalyst could be recycled up to six times without significant loss in its activity.
Albadi, Jalal,Alihosseinzadeh, Amir,Mardani, Mehdi
p. 308 - 313
(2015/09/28)

Acetylation of alcohols and phenols under solvent-free conditions using iron zirconium phosphate
Iron zirconium phosphate (ZPFe) nanoparticles were found to function as an efficient catalyst for the acetylation of a wide range of alcohols and phenols using acetic anhydride, generating good to excellent yields under solvent-free conditions. The steric and electronic properties of various substrates had a significant influence on the reaction conditions required to achieve the acetylation. The catalyst used in the current study was characterized by inductively coupled plasma-optical emission spectrometry, X-ray diffraction, N2 adsorption-desorption, scanning electron microscopy, and transmission electron microscopy. These analyses revealed that the interlayer distance in the catalyst increased from 7.5 to 9.3 ? when Fe3+ was intercalated between the layers, whereas the crystallinity of the material was reduced. This nanocatalyst could also be recovered and reused at least six times without any discernible decrease in its catalytic activity. This new method for the acetylation of alcohols and phenols has several important advantages, including mild and environmentally friendly reaction conditions, as well as good to excellent yields and a facile work-up.
Hajipour, Abdol R.,Karimi, Hirbod,Masti, Amir
p. 595 - 602
(2015/09/28)

Tribromoisocyanuric acid (TBCA) as a mild and metal free catalyst for the acetylation and formylation of hydroxyl groups under solvent free conditions
A convenient approach for acetylation and formylation of various types of alcohols and phenols with acetic anhydride and formic acid in the presence of Tribromoisocyanuric acid (TBCA) as catalyst is reported. The reactions were carried out under solvent-free condition and in good to high yields at room temperature. This present method is featured with relatively mild reaction conditions, simple operation, broad substrate scope, clean work-up, short reaction times, good to high yields, excellent selectivity and also avoids tedious purifications and the use of toxic reagents.
Hekmatian, Zahra,Khazaei, Ardeshir
p. 1565 - 1570
(2016/01/26)

A novel silver nanoparticle embedded mesoporous polyaniline (mPANI/Ag) nanocomposite as a recyclable catalyst in the acylation of amines and alcohols under solvent free conditions
A mesoporous polyaniline/silver (mPANI/Ag) nanocomposite has been prepared using mesoporous organic polymer polyaniline with silver nitrate via radical polymerization of aniline monomer in the presence of hydrochloric acid. The mPANI/Ag nanocomposite has been characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray spectra (EDX), Fourier transform infrared spectroscopy (FT-IR), and ultraviolet-visible absorption spectra (UV-vis). The XRD patterns indicated that the crystalline phase of Ag is cubic. TEM images show that the Ag nanoparticles are well dispersed in the mesoporous polyaniline matrix. The mPANI/Ag acts as an efficient heterogeneous nanocatalyst in the acylation of substituted amines and alcohols using acetic acid. The catalyst is air-stable, inexpensive, easy to prepare and can be reused several times without a significant decrease in activity and selectivity. This journal is
Mandi, Usha,Roy, Anupam Singha,Banerjee, Biplab,Islam, Sk. Manirul
p. 42670 - 42681
(2015/02/19)

Tribromo melamine as novel and versatile catalyst for the formylation and acetylation of alcohols
Tribromo melamine has been found to be an efficient and green organocatalyst for the acetylation and formylation reactions of alcohols with acetic anhydride and ethyl formate at room temperature and under mild reaction conditions.
Hajjami, Maryam,Ghorbani-Choghamarani, Arash,Karamshahi, Zahra,Norouzi, Masoomeh
p. 260 - 263
(2014/03/21)

Preparation and characterization of multi-walled carbon nanotubes (MWCNTs), functionalized with phosphonic acid (MWCNTs-C-PO3H2) and its application as a novel, efficient, heterogeneous, highly selective and reusable catalyst for acetylation of alcohols, phenols, aromatic amines, and thiols
A novel, efficient, heterogeneous, and reusable multi-walled carbon nanotubes (MWCNTs), functionalized with phosphonic acid (MWCNTs-C-PO 3H2) has been synthesized. The synthesized CNTs were characterized using some electron microscopic techniques such as scanning electron microscopy (SEM), atomic force microscopy (AFM), Energy dispersive X-ray spectroscopy (EDAX), and also some thermal and spectroscopic methods such as thermogravimetry (TG). The nitrogen adsorption behavior of the MWCNTs-C-PO3H2 catalyst was evaluated using the TG instrumentation system at 25°C. The catalyst was applied successfully for highly efficient and selective acetylation of alcohols, phenols, thiols and aromatic amines with acetic anhydride at room temperature under solvent-free conditions. The reusability of the catalyst was checked and the recovered catalyst was reused for five runs without significant loss in activity.
Dehghani, Farzaneh,Sardarian, Ali Reza,Doroodmand, Mohammad Mehdi
p. 673 - 684
(2014/05/20)

Acetylation of alcohols and phenols by zinc zirconium phosphate as an efficient heterogeneous catalyst under solvent-free conditions
An efficient method for the acetylation of a wide range of alcohols as well as phenols with acetic anhydride in good to excellent yields under solvent-free conditions, using zinc zirconium phosphate as the catalyst was investigated. The catalyst was characterized by XRD, inductivity coupled plasma-optical emission spectroscopy, and scanning electron microscope. Products are easily isolated and the protocol is mild and green, compared to the existing methods. Graphical abstract: [Figure not available: see fulltext.]
Hajipour, Abdol Reza,Karimi, Hirbod,Karimzadeh, Morteza
p. 1461 - 1472
(2014/09/30)

Acetylation of alcohols and phenols under solvent-free conditions using copper zirconium phosphate
Copper zirconium phosphate nanoparticles have been used as an efficient catalyst for the acetylation of a wide range of alcohols and phenols with acetic anhydride in good to excellent yields under solvent-free conditions. The steric and electronic properties of the different substrates had a significant influence on the reaction conditions required to achieve the acetylation. The catalyst used in the current study was characterized by inductively-coupled plasma optical emission spectroscopy, energy dispersive spectroscopy, X-ray diffraction, N2 adsorption-desorption, scanning electron microscopy, and transmission electron microscopy. These analyses revealed that the interlayer distance in the catalyst increased from 7.5 to 8.0 ? when Cu2+ was intercalated between the layers, whereas the crystallinity of the material was reduced. This nanocatalyst could also be recovered and reused at least six times without any discernible decrease in its catalytic activity. This new method for the acetylation of alcohols and phenols has several key advantages, including mild and environmentally friendly reaction conditions, as well as good to excellent yields and a facile work-up.
Hajipour, Abdol R.,Karimi, Hirbod
p. 1982 - 1989
(2015/09/28)

Nanomagnetic double-charged diazoniabicyclo[2.2.2]octane dichloride silica as a novel nanomagnetic phase-transfer catalyst for the aqueous synthesis of benzyl acetates and thiocyanates
Abstract Nanomagnetic double-charged diazoniabicyclo[2.2.2]octane dichloride silica hybrid (Fe3O4@SiO2/DABCO) was used as an efficient and magnetically recoverable phase-transfer catalyst (PTC) for nucleophilic substitution reactions of benzyl halides for the synthesis of benzyl acetates and thiocyanates in good to excellent yields at 100 C in water. No evidence for the formation of by-products, for example, isothiocyanate or benzyl alcohol was observed and the products were obtained in pure form without further purification. The catalyst was easily separated with the assistance of an external magnetic field from the reaction mixture and reused for several consecutive runs without significant loss of its catalytic efficiency.
Davarpanah, Jamal,Kiasat, Ali Reza
p. 98 - 103
(2013/09/24)

A lewis acid-promoted pinner reaction
Carbonitriles and alcohols react in a Lewis acid-promoted Pinner reaction to carboxylic esters. Best results are obtained with two equivalents of trimethylsilyl triflate as Lewis acid. Good yields are achieved with primary alcohols and aliphatic or benzylic carbonitriles, but the straightforward synthesis of acrylates and benzoates starting with acrylonitrile and benzonitrile, respectively, is similarly possible. Phenols are not acylated under these reaction conditions. The method has been used for the first total synthesis of the natural product monaspilosin. In the reaction of benzyl alcohols variable amounts of amides are formed in a Ritter-type side reaction.
Pfaff, Dominik,Nemecek, Gregor,Podlech, Joachim
supporting information
p. 1572 - 1577
(2013/10/22)

Preparation of esters and amides from carboxylic acids and N-formylation of amines promoted by 1,3,5-triazo-2,4,6-triphosphorine-2,2,4,4,6,6-hexachloride (TAPC)
A new method is described for the preparation of esters and amides promoted by TAPC from carboxylic acids using a solvent-free grinding technique. The solvent-free N-formylation of amines is also reported.
Bahrami, Kiumars,Khodaei, Mohammad M.,Targhan, Homa,Sheikh Arabi, Mehdi
supporting information
p. 5064 - 5068
(2013/09/02)

L-pyrrolidine-2-carboxylic acid-4-hydrogen sulfate (supported on silica gel) as a new and efficient catalyst for acylation of alcohols, phenols and amines under solvent-free conditions
In the present work, L-pyrrolidine-2-carboxylic acid-4-hydrogen sulfate, supported on silica gel was prepared and characterized by Mass spectroscopy, 1H NMR, 13CNMR, FT IR and elemental analysis (CHN) methods. This heterogenized catalyst can be used as an efficient catalyst for the acylation of alcohols, phenols, and amines with acetic anhydride under mild and solvent-free conditions. Simple work-up, stability of the catalyst, nontoxicity and good to high yields are the advantages of this work.
Hajjami, Maryam,Ghorbani-Choghamarani, Arash,Khani, Zahra
p. 324 - 329
(2013/07/26)

Fluorous 4-N,N-dimethylaminopyridium iodide: Recyclable organocatalysts by precipitation for acylation reaction at room temperature
A novel fluorous DMAP quaternary ammonium iodide salt organocatalyst was prepared. This fluorous organocatalyst was successfully employed to the acylation reaction at room temperature without the use of a stoichiometric amount of external base. It could be recovered 3 times from the reaction mixture by simple precipitation with excellent purity for direct reuse.
Yi, Wen-Bin,Zhu, Yi-Wei,Cai, Chun
p. 26 - 28
(2013/08/23)

In situ generated Ph3P(OAc)2as a novel reagent for the efficient acetylation of alcohols and thiols at room temperature
Ph3P, Br2, and ammonium acetate are used for the in situ generation of Ph3P(OAc)2, which was characterized by different NMR techniques. The Ph3P(OAc)2generated was used as a novel and efficient reagent for the acetylation of alcohols and thiols in acetonitrile at room temperature under homogeneous conditions. This reaction was also performed under heterogeneous conditions using 1,3,2,4- diazadiphosphetidine as an easily prepared, stable, and heterogeneous P(III) compound.
Iranpoor, Nasser,Firouzabadi, Habib,Elham, Etemadi Davan
p. 1813 - 1816
(2013/04/24)

Electrogenerated N-heterocyclic carbenes in the room temperature parent ionic liquid as an efficient medium for transesterification/acylation reactions
N-Heterocyclic carbenes (NHCs), generated by electrochemical reduction under galvanostatic control of 1,3-dialkylimidazolium-based ionic liquids, were employed as catalysts in transesterification reactions in the parent, room temperature ionic liquids (RTILs) as solvents, without the utilisation of any volatile organic solvent or base. The reaction between isopropenyl or ethyl acetate and an alcohol (not efficient in the absence of catalyst) was induced by the presence of an electrogenerated NHC, which seems to assist the proton transfer from the alcohol to the ester, yielding the corresponding acetate. The reaction also proceeds with methyl nicotinate as starting ester and 2-(diethylamino)ethanol or benzyl alcohol as alcohols and leads to the corresponding biologically active compounds, nicametate and benzyl nicotinate, in good yields. All products were isolated in good to excellent yields and complete recyclability of the ionic liquid as solvent has been demonstrated.
Chiarotto, Isabella,Feroci, Marta,Sotgiu, Giovanni,Inesi, Achille
supporting information
p. 326 - 331
(2013/02/25)

Acetylation of alcohols with acetic anhydride promoted by N,N,N-trimethylanilinium tribromide
A wide variety of alcohols were reacted with acetic anhydride at room temperature in the presence of a catalytic amount of N,N,N-trimethylanilinium tribromide to produce the corresponding alkyl acetates in good to excellent yields. Following this procedure, acetylation of primary, secondary, and tertiary alcohols has been performed under neutral conditions.
Ghorbani-Choghamarani,Shiri,Rostami
p. 1728 - 1730
(2014/08/05)

SBA-15-functionalized sulfonic acid confined acidic ionic liquid: A powerful and water-tolerant catalyst for solvent-free esterifications
Incorporating a hydrophobic Bronsted acid ionic liquid (HBAIL) inside the nanospaces of SBA-15-Pr-SO3H led to a hydrophobic super Bronsted acid catalyst, which showed excellent catalytic performance in direct esterification of alcohols and carboxylic acids at ambient temperature under solvent-free conditions. The Royal Society of Chemistry 2012.
Karimi, Babak,Vafaeezadeh, Majid
supporting information; experimental part
p. 3327 - 3329
(2012/04/23)

Polyvinylpolypyrrolidone-bound boron trifluoride: A highly efficient catalyst for acylation of alcohols, phenols and trimethylsilyl ethers by acetic anhydride
A highly efficient method for the acylation of alcohols, phenols and trimethylsilyl ethers with acetic anhydride is described using polyvinylpolypyrrolidone-bound boron trifluoride (PVPP-BF3) under mild and heterogeneous conditions at room temperature in good to excellent yields. The polyvinylpolypyrrolidone-boron trifluoride complex shows more water tolerant, non-corrosive and stable solid catalyst elevated Lewis acid properties.
Mokhtary, Masoud,Qandalee, Mohammad,Najafizadeh, Faranak
experimental part
p. 389 - 393
(2012/08/28)

Iron(III) tosylate catalyzed acylation of alcohols, phenols, and aldehydes
Iron(III) p-toluenesulfonate (tosylate) is an efficient catalyst for acetylation of alcohols, phenols, and aldehydes. The acetylation of 1° and 2° alcohols, diols, and phenols proceeded smoothly with 2.0 mol % of catalyst. However, the reaction worked well with only a few 3° alcohols. The methodology was also applicable to the synthesis of a few benzoate esters but required the use of 5.0 mol % catalyst. Aldehydes could also be converted into the corresponding 1,1-diesters (acylals) under the reaction conditions. Iron(III) tosylate is an inexpensive, and easy to handle, commercially available catalyst.
Baldwin, Neil J.,Nord, Anna N.,O'Donnell, Brendan D.,Mohan, Ram S.
p. 6946 - 6949
(2013/01/15)

Sonochemical synthesis of silica and silica sulfuric acid nanoparticles from rice husk ash: A new and recyclable catalyst for the acetylation of alcohols and phenols under heterogeneous conditions
Silica nanoparticles were synthesized from rice husk ash at room temperature by sonochemical method. The feeding rate of percipiteting agent and time of sonication were investigated. The nanostructure of the synthesized powder was realized by the FE-SEM photomicrograph, FT-IR spectroscopy, XRD and XRF analyses. These analytical observations have revealed that the nano-sized amorphous silica particles are formed and they are spheroidal in shape. The average particle size of the silica powders is found to be around 50 nm. The as-synthesized silica nanoparticles were subsequently modified with chlorosulfonic acid and prepared silica sulfuric acid nanoparticles, which were employed as an efficient catalyst for the acylation of alcohols and phenols with acetic anhydride in excellent yields under solvent-free conditions at room temperature. This reported method is simple, mild, and environmentally viable and catalyst can be simply recovered and reused over 9 times without any significant loss of its catalytic activity.
Salavati-Niasari, Masoud,Javidi, Jaber
p. 705 - 712
(2013/02/22)

Highly efficient solvent-free acetylation of alcohols with acetic anhydride catalyzed by recyclable sulfonic acid catalyst (SBA-15-Ph-Pr-SO3H)- An environmentally benign method
The catalytic activity of highly thermal stable, hydrophobic, and complete heterogeneous propylsulfonic acid functionalized nanostructured SBA-15 for excellent acetylation of alcohols and phenols with acetic anhydride at ambient temperature in solvent-free conditions was examined under environmentally benign reaction conditions. The salient features of this protocol are the absence of solvent, a green experimental procedure, and simple reusability of the catalyst (at least five reaction cycles).
Zareyee, Daryoush,Ghadikolaee, Abdollah Razaghi,Khalilzadeh, Mohammad A.
experimental part
p. 464 - 468
(2012/06/16)

New porphyrin-polyoxometalate hybrid materials: Synthesis, characterization and investigation of catalytic activity in acetylation reactions
New hybrid complexes based on covalent interaction between 5,10,15,20-tetrakis(4-aminophenyl)porphyrinatozinc(ii) and 5,10,15,20- tetrakis(4-aminophenyl)porphyrinatotin(iv) chloride, and a Lindqvist-type polyoxometalate, Mo6O192-, were prepared. These new porphyrin-polyoxometalate hybrid materials were characterized by 1H NMR, FT IR and UV-Vis spectroscopic methods and cyclic voltammetry. These spectro- and electrochemical studies provided several spectral data for synthesis of these compounds. Cyclic voltammetry showed the influence of the polyoxometalate on the redox process of the porphyrin ring. The catalytic activity of tin(iv)porphyrin-hexamolybdate hybrid material was investigated in the acetylation of alcohols and phenols with acetic anhydride. The reusability of this catalyst was also investigated.
Araghi, Mehdi,Mirkhani, Valiollah,Moghadam, Majid,Tangestaninejad, Shahram,Mohammdpoor-Baltork, Iraj
p. 11745 - 11752
(2013/02/23)

Ceria nanoparticles as an efficient catalyst for oxidation of benzylic CH bonds
Catalytic oxidation of benzylic CH bonds with potassium bromate to carbonyl compounds was studied in the presence of ceria nanoparticles (NPs). Aldehydes and ketones in high yields were obtained when the oxidation was conducted in water/1,4-dioxane/acetic acid (AcOH) by ratio 5/1/1 (v/v/v). Benzyl esters were also yielded as the main products from the oxidation of benzylic CH bonds with potassium bromate in the presence of ceria NPs in glacial acetic acid. In comparison with other methods reported in the literature, ceria NPs as an efficient catalyst in oxidation of benzylic CH bonds have advantageous such as selectivity, recyclability, high reaction rate, and high yield of product because of their large specific surface area to volume ratio.
Akhlaghinia, Batool,Ebrahimabadi, Hossein,Goharshadi, Elaheh K.,Samiee, Sara,Rezazadeh, Soodabeh
experimental part
p. 67 - 72
(2012/05/20)

Novel peptide foldameric motifs: A step forward in our understanding of the fully-extended conformation/310-helix coexistence
The fully-extended, multiple C5, conformation or 2.05 helix is a very appealing peptide secondary structure, in particular for its potential use as a molecular spacer, as it is characterized by the longest elevation (as high as 3.62 A) between the α-carbon atoms of two consecutive α-amino acids. Despite this intriguing property, however, it is only poorly investigated and understood. Here, using a complete series of Cα,α-diethylglycine (Deg) homo-oligopeptide esters to the pentamer level, we exploited the properties of a fluorophore and a quencher, synthetically positioned at the N- and C-termini of the main chain, respectively, to check the applicability of the fully-extended conformation as a rigid molecular spacer. The fluorescence study was complemented by FT-IR absorption and NMR conformational investigations. The X-ray diffraction structures of selected compounds are also reported. Unfortunately, we find that, even in a solvent of low polarity, such as chloroform, in this peptide series an equilibrium does take place between the fragile fully-extended conformation and the 310-helical structure, the latter becoming more and more stable as the main chain is elongated. Since the Deg homo-peptide esters lacking any terminal aromatic group, previously investigated, are known to adopt a stable fully-extended conformation in chloroform solution, we tend to attribute the 3D-structure instability observed in this work to the presence of multiple aromatic rings in their blocking groups. The Royal Society of Chemistry 2012.
Formaggio, Fernando,Crisma, Marco,Ballano, Gema,Peggion, Cristina,Venanzi, Mariano,Toniolo, Claudio
experimental part
p. 2413 - 2421
(2012/04/11)

Enhancement of activity and stability of lipase by microemulsion-based organogels (MBGs) immobilization and application for synthesis of arylethyl acetate
Lipase from Candida rugosa (CRL) was immobilized in microemulsion-based organogels (MBGs) and subsequently applied in large scale synthesis of arylethyl acetate in organic solvents as a more stable and efficient catalyst. Various reaction parameters (solvent, temperature, substrate concentration) were investigated for enhancement of ester production. Thermal and operational stabilities were improved compared with free CRL showing its potential for continuous applications. They were more stable at 50-60 °C and showed good recovery activity, which retained 70% of their initial activity after 16 recycles in organic media and remained constant at that level thereafter. Moreover, the immobilized lipase can maintain high catalytic activity in a variety of organic solvents, while free lipase was easily inactivated in polar solvent. A series of alcohols with different substitution groups were successfully applied in CRL MBGs-catalyzed transesterification, affording higher conversions than those with the free enzyme.
Zhang, Wei-Wei,Wang, Na,Zhou, Yu-Jie,He, Ting,Yu, Xiao-Qi
experimental part
p. 65 - 71
(2012/07/13)

H3PW12O40at the[bmim][FeCl4]: A green catalytic system for alkoxymethylation of alcohols and their one-pot interconversion to acetates and TMS-ethers
12-Tungstophosphoric acid immobilized on [bmim][FeCl4] was found to be an efficient catalyst for chemoselective methoxymethylation and ethxoymethylation of alcohols and also one-pot conversion of MOM- or EOM-ethers to their corresponding acetates and TMS-ethers under thermal conditions and microwave irradiation. These procedures were simple, rapid and the corresponding products were obtained in high yields. The catalyst exhibited remarkable reactivity and was reusable.
Mohammadpoor-Baltork,Moghadam,Tangestaninejad,Mirkhani,Khosropour,Mirjafari
experimental part
p. 513 - 524
(2012/06/16)

[InCl4]: An efficient catalyst-medium for alkoxymethylation of alcohols and their interconversion to acetates and TMS-ethers
A simple, green and chemoselective method for methoxymethylation and ethoxymethylation of primary and secondary alcohols using a Lewis acidic room temperature ionic liquid, [C4mim][InCl4], as catalyst and reaction medium under ambient temperature, microwave and ultrasonic irradiations is reported. In this catalytic system, the corresponding MOM-and EOM-ethers are obtained in excellent yields and in short reaction times. Furthermore, this catalytic system was used for mild and efficient transformations of these protected alcohols to their corresponding acetates and trimethylsilyl ethers under thermal conditions and microwave and ultrasonic irradiations.
Mohammadpoor-Baltork, Iraj,Moghadam, Majid,Tangestaninejad, Shahram,Mirkhani, Valiollah,Khosropour, Ahmad Reza,Mirjafari, Arsalan
experimental part
p. 568 - 579
(2012/05/05)

Synthesis and reactivity studies of a new reagent, ethyltriphenylphosphonium tribromide
A new reagent, ethyltriphenyl phosphonium tribromide (ETPPTB), has been synthesized and studied. Results show that the reagent is quite efficient for various reactions such as organic bominations, acylations, and isothiocyanate preparation. Copyright
Jamir, Latonglila,Alimenla,Kumar, Anil,Sinha, Dipak,Sinha, Upasana B.
experimental part
p. 147 - 155
(2011/03/17)

Silver triflate catalyzed acetylation of alcohols, thiols, phenols, and amines
A variety of alcohols, thiols, phenols, and amines were subjected to acetylation reaction using acetic anhydride in the presence of catalytic quantity of silver triflate. The method described has a wide range of applications, proceeds under mild conditions, does not involve cumbersome workup, and the resulting products are obtained in high yields within a reasonable time. Georg Thieme Verlag Stuttgart · New York.
Das, Rima,Chakraborty, Debashis
experimental part
p. 1621 - 1625
(2011/06/25)

Polystyrene-bound electron-deficient tin(IV) porphyrin: A new, highly efficient, robust and reusable catalyst for acetylation of alcohols and phenols with acetic anhydride
In the present work, tetrakis(p-aminophenyl)porphyrinatotin(IV) trifluoromethanesulfonate, [SnIV(TNH2PP)(OTf) 2], supported on chloromethylated polystyrene was prepared and characterized by elemental analysis, FT IR and diffuse reflectance UV-Vis spectroscopic methods. This new heterogenized catalyst was used for acetylation of alcohols and phenols with acetic anhydride in short reaction times and high yields. The catalyst is of high reusability and stability in the acetylation reactions and was recovered several times without loss of its initial activity and catalyst leaching.
Moghadam, Majid,Tangestaninejad, Shahram,Mirkhani, Valiollah,Mohammadpoor-Baltork, Iraj,Gharaati, Shadab
scheme or table
p. 1080 - 1087
(2012/03/11)