- Direct Conversion of Trimethylsilyl and Tetrahydropyranyl Ethers into Esters with Acid Chlorides in the Presence of Montmorillonite K-10
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A simple method is described for an efficient conversion of variety of trimethylsilyl (TMS) and tetrahydropyranyl (THP) ethers into their corresponding esters with acid chlorides in the presence of montmorillonite K-10.
- Movassagh, Barahman,Atrak, Kobra
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Read Online
- Fractional distribution of graphene oxide and its potential as an efficient and reusable solid catalyst for esterification reactions
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Graphene oxide (GrO) prepared by the Hummers method was separated into three different fractions (GrO5000, GrO2000, and GrOres) on the basis of their dispersion stability in the water. Infrared, nuclear magnetic resonance, X-ray photoelectron spectroscopy, and elemental analyses revealed that GrO5000 possesses a high degree of oxygen functionalities including phenolic, carboxylic, and -OSO2H groups, compared with the other fractions. The GrO5000 was found to be a highly efficient and reusable solid catalyst for the esterification of various carboxylic acids with a variety of alcohols to furnish corresponding esters in high to excellent yields. The catalytic activity of the GrO5000 was attributed to the ability of highly polar GrO5000 scaffold to adsorb/attract reactants, where the acid functionalities of GrO5000 facilitated the esterification process efficiently. The chemical and structural features of GrO5000 were discussed to understand the improved catalytic activity compared with GrO2000 and conventional solid acid catalysts.
- Mungse, Harshal P.,Bhakuni, Niharika,Tripathi, Deependra,Sharma, Om P.,Sain, Bir,Khatri, Om P.
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Read Online
- Genome mining reveals new bacterial type I Baeyer-Villiger monooxygenases with (bio)synthetic potential
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Baeyer-Villiger monooxygenases (BVMOs) are oxidorreductases that catalyze the oxidation of ketones in a very selective manner. By genome mining we detected seven putative type I BVMOs in Bradyrhizobium diazoefficiens USDA 110. As we established the phylogenetic relationships among them and with other type I BVMOs, we found out that they belong to different clades of the phylogenetic tree. Thus, we decided to clone and heterologously express five of them. Three of them, each one from a divergent phylogenetic group, were obtained as soluble proteins, allowing us to proceed with their biocatalytic assessment and enzymatic characterization. As to substrate scope and selectivity, we observed a complementary behavior among the three BVMOs. BVMO2 was the more versatile biocatalyst in whole-cell systems while BVMO4 and BVMO5 showed a narrow substrate profile with preference for linear ketones and particular regioselectivity for (±)-cis-bicyclo[3.2.0]hept-2-en-6-one.
- Bianchi, Dario A.,Carabajal, María Ayelén,Ceccoli, Romina D.,Rial, Daniela V.
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- Magnetically recoverable AlFe/Te nanocomposite as a new catalyst for the facile esterification reaction under neat conditions
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In this work, a new Fe3O4/AlFe/Te nanocomposite was synthesized by a one-step sol–gel method. The Fe3O4 magnetic nanoparticles (MNPs) were prepared and then mixed with aluminum telluride (Al2Te3) in an alkali medium to produce the desired catalyst. After characterization of the Fe3O4/AlFe/Te nanocomposite by SEM, TEM, EDS, XRD, and ICP analyses, it was used in the esterification reaction. This heterogeneous catalyst showed high catalytic activity in the esterification of commercially available carboxylic acids with various alcohols to produce the desired esters at high conversions under neat conditions. The Fe3O4/AlFe/Te nanocomposites were separated from the reaction mixture via an external magnet and re-used 8 times without significant loss of catalytic activity.
- Alavi, Seyed Jamal,Sadeghian, Hamid,Seyedi, Seyed Mohammad,Eshghi, Hossein,Salimi, Alireza
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- TiCl4/Et3N-Mediated Condensation of Acetate and Formate Esters: Direct Access to β-Alkoxy- and β-Aryloxyacrylates
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A methodology to build (E)-β-alkoxy- and (E)-β-aryloxyacrylate moieties from acetate and formate esters promoted by the TiCl4/Et3N system is presented. The reaction is compatible with a broad range of structural skeletons and elapses through an unusual condensation pathway. Taking into account the obtained results, we propose a plausible mechanism involving a bimetallic titanium intermediate for this type of transformation.
- álvarez-Calero, José María,Jorge, Zacarías D.,Massanet, Guillermo M.
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supporting information
p. 6344 - 6347
(2016/12/23)
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- Microwave-Assisted Catalytic Acetylation of Alcohols by Gold-Nanoparticle-Supported Gadolinium Complex
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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
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p. 661 - 672
(2015/10/29)
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- Vitamin B1 supported on silica-encapsulated γ-Fe 2O3 nanoparticles: Design, characterization and application as a greener biocatalyst for highly efficient acylation
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A new magnetic catalyst was synthesized by the immobilization of vitamin B1 (thiamine hydrochloride) on the surface of silica-encapsulated γ-Fe2O3 nanoparticles. Its capability was evaluated in the acylation of alcohols and phenols with acetic anhydride under solvent-free conditions and afforded the desired products in high yield. This novel magnetic organocatalyst could be separated from the reaction vessel by use of an external magnet and recovered 5 times without a significant loss of its activity. The amount of loaded vitamin B1 on the silica-encapsulated γ-Fe2O3 was assigned by TGA and confirmed by back titration. Availability, cheapness and low toxicity are reasons associated with the utilization of vitamin B1 as a catalyst. The catalyst has been characterized by FT-IR, XRD, SEM, VSM and TG/DTA. The Royal Society of Chemistry.
- Azizi, Kobra,Heydari, Akbar
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p. 8812 - 8816
(2014/03/21)
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- A simple acetylation of alcohols using ZnO nanopowder synthesized by microwave irradiation
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An efficient and selective method for acetylation of alcohols using ZnO nanopowder is described. In this method, alcohols are refluxed with a mixture of CH3COOH in the presence of catalytic amounts of ZnO nanopowder to afford their corresponding esters in good yields. This methodology is highly efficient for various structurally different alcohols: 1°, 2°, 3°. The prepared nano zinc oxide used in acetylation of alcohols which in comparison to ordinary ZnO has apparent advantages in promoting the yields of product formation.
- Javaherian, Mohammad,Sabzi, Hashem Eskandari
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p. 631 - 634
(2014/06/23)
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- Fractional distribution of graphene oxide and its potential as an efficient and reusable solid catalyst for esterification reactions
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Graphene oxide (GrO) prepared by the Hummers method was separated into three different fractions (GrO5000, GrO2000, and GrOres) on the basis of their dispersion stability in the water. Infrared, nuclear magnetic resonance, X-ray photoelectron spectroscopy, and elemental analyses revealed that GrO5000 possesses a high degree of oxygen functionalities including phenolic, carboxylic, and -OSO2H groups, compared with the other fractions. The GrO5000 was found to be a highly efficient and reusable solid catalyst for the esterification of various carboxylic acids with a variety of alcohols to furnish corresponding esters in high to excellent yields. The catalytic activity of the GrO5000 was attributed to the ability of highly polar GrO5000 scaffold to adsorb/attract reactants, where the acid functionalities of GrO5000 facilitated the esterification process efficiently. The chemical and structural features of GrO5000 were discussed to understand the improved catalytic activity compared with GrO2000 and conventional solid acid catalysts.
- Mungse, Harshal P.,Bhakuni, Niharika,Tripathi, Deependra,Sharma, Om P.,Sain, Bir,Khatri, Om P.
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p. 944 - 951
(2015/08/25)
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- Cloning and expression of a Baeyer-Villiger monooxygenase oxidizing linear aliphatic ketones from Dietzia sp. D5
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A Baeyer-Villiger monooxygenase has been identified in the genome sequence of Dietzia sp. D5. Sequence similarity search revealed that the enzyme belongs to a group of BVMOs that are closely related to ethionamide monooxygenase from Mycobacterium tuberculosis (EthA). The BVMO was expressed in E. coli BL21-CodonPlus(DE3)-RP and the best expression was achieved when the E. coli cells were cultivated in terrific broth (TB) at 15 °C and induced with 0.1 mM of IPTG. Since the purified enzyme did not show any measurable activity, the substrate scope of the BVMO has been determined using whole-cell and crude cell extract systems. The enzyme was most active towards linear aliphatic substrates. However, it has shown a moderate degree of conversion for cyclobutanone, 2-methylcyclohexanone, bicyclo[3.2.0]hept-2-en-6-one, phenylacetone and thioanisole. There was no detectable conversion of ethionamide, cyclohexanone and acetophenone.
- Bisagni, Serena,Smus?, Justyna,Chávez, Georgina,Hatti-Kaul, Rajni,Mamo, Gashaw
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p. 161 - 169
(2014/12/11)
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- Solvent-free acetylation and tetrahydropyranylation of alcohols catalyzed by recyclable sulfonated ordered nanostructured carbon
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Rapid and practical green acetylation and tetrahydropyranylation routes of structurally diverse alcohols and phenols were applied under solvent-free reaction conditions providing excellent yields, using catalytic amounts of environmentally friendly sulfonated ordered nanoporous carbon (CMK-5-SO 3H). Non-toxic nature of the catalyst, its easy handling, recovery and reusability, and the absence of any solvent characterize the presented procedures as efficient methods. These procedures provide methods for the separation of the product by simple filtration.
- Zareyee, Daryoush,Alizadeh, Parastoo,Ghandali, Mohammad S.,Khalilzadeh, Mohammad A.
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p. 713 - 721
(2013/07/26)
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- Discovery of Baeyer-Villiger monooxygenases from photosynthetic eukaryotes
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Baeyer-Villiger monooxygenases are attractive "green" catalysts able to produce chiral esters or lactones starting from ketones. They can act as natural equivalents of peroxyacids that are the catalysts classically used in the organic synthesis reactions, consisting in the cleavage of CC bonds with the concomitant insertion of an oxygen atom. In this study, two type I BVMOs have been identified for the first time in photosynthetic eukaryotic organisms, the red alga Cyanidioschyzon merolae (Cm) and the moss Physcomitrella patens (Pp). A biocatalytic characterization of these newly discovered enzymes, expressed in recombinant forms, was carried out. Both enzymes could be purified as holo enzymes containing a FAD cofactor. Their thermostability was investigated and revealed that the Cm-BVMO is the most thermostable type I BVMO with an apparent melting temperature of 56 C. Substrate profiling revealed that both eukaryotic BVMOs accept a wide range of ketones which include aromatic, aliphatic, aryl aliphatic and bicyclic ketones. In particular, linear aliphatic ketones (C9 and C12), carrying the keto functionality in different positions, resulted to be the best substrates in steady state kinetic analyses. In order to restore the BVMO-typifying sequence motif in the Pp-BVMO, a mutant was prepared (Y160H). Intriguingly, this mutation resulted in higher activities on most tested substrates. The recombinant enzymes displayed kcat values in the 0.1-0.2 s-1 range, which is relatively low when compared with other known type I BVMOs. This may hint to a role in secondary metabolism in these photosynthetic organisms, though their exact function remains to be established.
- Beneventi, Elisa,Niero, Mattia,Motterle, Riccardo,Fraaije, Marco,Bergantino, Elisabetta
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p. 145 - 154
(2013/12/04)
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- 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
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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.
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experimental part
p. 464 - 468
(2012/06/16)
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- New porphyrin-polyoxometalate hybrid materials: Synthesis, characterization and investigation of catalytic activity in acetylation reactions
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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
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p. 11745 - 11752
(2013/02/23)
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- Poly-(N,N′-dibromo-N-ethyl-benzene-1,3-disulfonamide) and N,N,N′,N′- tetrabromobenzene-1,3-disulfonamide as highly efficient catalysts, and (AC2O/SIO2) as a heterogeneous system for the acetylation of alcohols, amines, and thiols under microwave irradiation
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Chemical Equation Presented Poly-(N,N′-dibromo-N-ethyl-benzene-1,3- disulfonamide) (PBBS) and N,N,N′,N′-tetrabromobenzene-1,3- disulfonamide (TBBDA) are good activators and catalytic reagents for the acetylation of alcohols, amines, and thiols. The presented method has the advantages of mild conditions, chemoselectivity, and good to high yields, and uses noncorrosive, inexpensive, recyclable, and environmentally friendly catalysts. We have also demonstrated that combining SiO2 with microwave energy provides an efficient, fast, convenient, and easy workup procedure for the synthesis of mono- and disubstituted acetates, acetamides, and thioacetamides. Copyright Taylor & Francis Group, LLC.
- Veisi, Hojat,Ghorbani-Vaghei, Ramin,Eskandari, Hosna,Hemmati, Saba,Rezaei, Ardashir,Hajinazari, Somaye,Far, Mohammad Raoof Heidari,Entezari, Azam
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experimental part
p. 213 - 219
(2011/04/24)
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- Electron-deficient [TiIV(salophen)(OTf)2]: A new and highly efficient catalyst for the acetylation of alcohols and phenols with acetic anhydride
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In the present work, a highly efficient method for acetylation of alcohols and phenols with acetic anhydride catalyzed by high-valent [Ti IV(salophen)(OTf)2] is reported. Under these conditions, primary, secondary and tertiary alcohols as well as phenols were acetylated with short reaction times and high yields. The catalyst was reused several times without loss of its catalytic activity.
- Yadegari, Maryam,Moghadam, Majid,Tangestaninejad, Shahram,Mirkhani, Valiollah,Mohammadpoor-Baltork, Iraj
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experimental part
p. 2237 - 2243
(2011/10/03)
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- Investigation of catalytic activity of high-valent vanadium(IV) tetraphenylporphyrin: A new, highly efficient and reusable catalyst for acetylation of alcohols and phenols with acetic anhydride
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In the present work, the catalytic activity of high-valent tetraphenylporphyrinatovanadium(IV) trifluoromethanesulfonate, [V IV(TPP)(OTf)2], in the acetylation of alcohols and phenols with Ac2O is reported. This new V(IV) catalyst was used as an efficient catalyst for not only primary alcohols (benzylic and aliphatic) but also sterically-hindered secondary and tertiary alcohols with acetic anhydride and the corresponding acetates were obtained in 85-99% yield and 0.5-15 min. Acetylation of phenols with acetic anhydride was also performed to afford the desired acetates in 88-99% and 1.5-20 min. This catalyst can be reused several times without loss of its catalytic activity.
- Taghavi, S. Abdolmanaf,Moghadam, Majid,Mohammadpoor-Baltork, Iraj,Tangestaninejad, Shahram,Mirkhani, Valiollah,Khosropour, Ahmad Reza
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experimental part
p. 159 - 164
(2011/12/16)
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- Polystyrene-bound electron-deficient tin(IV) porphyrin: A new, highly efficient, robust and reusable catalyst for acetylation of alcohols and phenols with acetic anhydride
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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
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scheme or table
p. 1080 - 1087
(2012/03/11)
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- H6GeMo10V2O40·16H 2O nanoparticles prepared by hydrothermal method: A new and reusable heteropoly acid catalyst for highly efficient acetylation of alcohols and phenols under solvent-free conditions
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A new Keggin-type heteropoly acid, namely decamolybdodivanadogermanic acid (H6GeMo10V2O40·16H 2O), with nanosized particles (5-8 nm), has been synthesized by a hydrothermal method and characterized by elemental analysis, thermogravimetric analysis (TGA), powder X-ray diffractometry (XRD), Fourier-transform infrared spectroscopy (FTIR), UV-Visible spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and potentiometric titration. H6GeMo10V2O40·16H 2O revealed high catalytic activity for acetylation of various alcohols and phenols with acetic anhydride at room temperature (298 ± 2 K) and under solvent-free conditions. The catalyst can be easily recovered and used repeatedly for five cycles with a slight loss of activity. The catalytic activity of H6GeMo10V2O40· 16H2O was higher than that of other Keggin-type heteropoly acids, such as H3PW12O40, H3PMo 12O40 and H4SiW12O40.
- Farhadi, Saeid,Zareisahamieh, Reza,Zaidi, Masoumeh
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experimental part
p. 1323 - 1332
(2012/04/04)
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- Synthesis of C7-C16-Alkyl maltosides in the presence of tin(IV) chloride as a lewis acid catalyst
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The synthesis of C7- to C16-alkyl maltosides in the presence of tin(IV) chloride as Lewis acid catalyst was performed. The characterization of the products and theoretical investigation of the crucial step in the synthesis were carried out. The preparation of the β-maltosides required reaction time of 1 h, and that of the α-maltosides was 72 h. The side products were the α-D-maltosidechloride and 2-hydroxy-β-maltoside, respectively. The PM3 calculation confirmed the formation of the kinetically controlled β-product.
- Markovic, Zoran,Predojevic, Jasmina,Manojlovic, Nedeljko T.
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experimental part
p. 83 - 90
(2012/05/20)
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- [InCl4]: An efficient catalyst-medium for alkoxymethylation of alcohols and their interconversion to acetates and TMS-ethers
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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
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experimental part
p. 568 - 579
(2012/05/05)
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- H3PW12O40at the[bmim][FeCl4]: A green catalytic system for alkoxymethylation of alcohols and their one-pot interconversion to acetates and TMS-ethers
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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
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experimental part
p. 513 - 524
(2012/06/16)
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- A green method for selective acetylation of primary alcohols using ethyl acetate and solid potassium carbonate
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A simple and selective acetylation of primary alcohols in the presence of other reactive functionalities such as secondary alcohol, phenol, acetonide and amine is described using mild ethyl acetate as the acetyl-transfer agent and solid potassium carbonate as the catalyst.
- Mallesha,Rao, S. Prahlada,Suhas,Gowda, D. Channe
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experimental part
p. 536 - 539
(2011/11/30)
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- Spinel-type zinc aluminate (ZnAl2O4) nanoparticles prepared by the co-precipitation method: A novel, green and recyclable heterogeneous catalyst for the acetylation of amines, alcohols and phenols under solvent-free conditions
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Zinc aluminate (ZnAl2O4) nanoparticles with an average particle size of about 8 nm were easily prepared by the co-precipitation method using aqueous ammonia solution as the precipitating agent. This nanosized spinel-type oxide was characterized by TGA, XRD, FT-IR, TEM, and surface area measurement and used as the heterogeneous catalyst for the acetylation reaction. Efficient acetylation of various amines, alcohols and phenols was carried out over ZnAl2O4 nanoparticles using acetic anhydride and/or acetyl chloride as the acetylating agents at room temperature without the use of a solvent. The method is highly selective, allowing the alcoholic hydroxyl group to be protected while the phenolic hydroxyl group remains intact, and the amine group can be acetylated in the presence of the hydroxyl group. This method is fast and has a high yield. It is also clean, safe, cost effective, compatible with substrates that have other functional groups and very suitable for practical organic synthesis. In addition, the catalyst can be reused without significant loss of activity. Indeed, the catalytic activity of the ZnAl2O4 nanoparticles is higher than that of bulk ZnAl2O4.
- Farhadi, Saeid,Panahandehjoo, Somayeh
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scheme or table
p. 293 - 302
(2010/09/04)
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- Bismuth(III) bromide in organic synthesis. A catalytic method for the allylation of tetrahydrofuranyl and tetrahydropyranyl ethers
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A bismuth bromide-catalyzed (10.0 mol %) multicomponent reaction involving the allylation of THF- and THP-ethers, followed by in situ derivatization with acetic anhydride to generate highly functionalized esters has been developed under solvent-free conditions. To the best of our knowledge, this is the first report of a catalytic procedure for the allylation of THF- and THP-ethers to yield ring-opened products.
- Krabbe, Scott W.,Angeles, Veronica V.,Mohan, Ram S.
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supporting information; experimental part
p. 5643 - 5645
(2010/11/18)
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- Rapid and efficient method for acetylation of alcohols and phenols with acetic anhydride catalyzed by silica sulfate
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A rapid and efficient method is described for acetylation of a series of alcohols and phenols with acetic anhydride catalyzed by silica sulfate solid acid at room temperature or at refluxing temperature in excellent yield. Copyright Taylor & Francis Group, LLC.
- Jin, Tong-Shou,Zhao, Ying,Liu, Li-Bin,Chen, Zhuo,Li, Tong-Shuang
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p. 1221 - 1227
(2007/10/03)
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- Molecular iodine catalyzed selective acetylation of alcohols with vinyl acetate
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Molecular iodine is found to catalyze the acetylation of alcohols efficiently with vinyl acetate. The reaction is mild and selective with good to high yields. Molecular iodine displays significant functional group tolerance, being compatible with methoxy, double bonds, spiroketals, ketals and phenolic hydroxyl functions.
- Bosco, J.W. John,Agrahari, Aditya,Saikia, Anil K.
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p. 4065 - 4068
(2007/10/03)
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- Acetylation of alcohols catalyzed by dodeca-tungsto(molybdo)phosphoric acid
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Acetylation of primary, secondary, and tertiary alcohols was carried out in some refluxing alkyl acetates and in two carboxylic acids with the participation of catalytic amounts of H3PW12O 40, H3PMo12O40, and H 14P5W30O110 with good yields and high stereo(regio)specificity under mild reaction condition. H 3PW12O40 and H3PMo 12O40 have also shown excellent reactivity in the formylation of 1-butanol with ethyl formate at room temperature and in short reaction times. Heteropolyacid catalysts could be separated after a simple work up and reused for several times. Springer-Verlag 2006.
- Tayebee, Reza,Alizadeh, Mohammad H.
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p. 1063 - 1069
(2007/10/03)
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- Zinc oxide (ZnO) as a new, highly efficient, and reusable catalyst for acylation of alcohols, phenols and amines under solvent free conditions
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Zinc oxide (ZnO) is a highly efficient catalyst for the acylation of a variety of alcohols, phenols and amines with acid chlorides or acid anhydrides under solvent free conditions. Primary, secondary, tertiary, allylic and benzylic alcohols, diols and phenols with electron donating or withdrawing substituents can be easily acylated in good to excellent yield.
- Hosseini Sarvari, Mona,Sharghi, Hashem
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p. 10903 - 10907
(2007/10/03)
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- Efficient one-step conversion of tetrahydropyranyl ethers into acetates and formates in the presence of potassium dodecatungstocobaltate K 5CoW12O40·3H2O
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Tetrahydropyranyl ethers derived from primary alcohols were directly and efficiently converted into the corresponding acetates and formates by the action of ethyl acetate, acetic acid, acetic anhydride, and ethyl formate in the presence of a catalytic amount of potassium dodecatungstocobaltate K 5CoW12O40 ? 3H2O. Tetrahydropyranyl ethers derived from secondary alcohols and phenols can also be transformed into the corresponding acetates with the use of acetic anhydride, but K5CoW12O40 ? 3H2O was ineffective for esterification with ethyl acetate, acetic acid, and ethyl formate.
- Rafiee,Tangestaninejad,Habibi,Mohammadpoor-Baltork,Mirkhani
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p. 393 - 395
(2007/10/03)
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- A fast and convenient procedure for the acetylation of alcohols
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Treatment of different steroidal and aliphatic alcohols with BF3 · OEt2 and acetic anhydride for 5 seconds produced complete acetylation in high to quantitative yields.
- Martinez-Pascual, Roxana,Vinas-Bravo, Omar,Meza-Reyes, Socorro,Iglesias-Arteaga, Martin A.,Sandoval-Ramirez, Jesus
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p. 4591 - 4596
(2007/10/03)
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- Cerium polyoxometalate as a reusable catalyst for acetylation and formylation of alcohols
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Efficient esterification of primary and sterically-hindered secondary or tertiary alcohols with acetic anhydride was achieved in the presence of ammonium decatungestocerate(IV) icosahydrate, (NH4)8[CeW 10O36]·OH2O, as catalyst in high yields. Primary and secondary alcohols were also converted to their corresponding acetates and formates with acetic acid and ethyl formate in the presence of this catalyst. Easy work-up, non-toxicity, reusability, and stability of the catalyst are noteworthy advantages of this method. Springer-Verlag 2004.
- Mirkhani, Valiollah,Tangestaninejad, Shahram,Moghadam, Majid,Yadollahi, Bahram,Alipanah, Ladan
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p. 1257 - 1263
(2007/10/03)
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- BF3 etherate-induced formation of C7-C 16-alkyl β-D-glucopyranosides
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BF3 etherate-induced formation of C7-C 16-alkyl D-glucopyranosides is used as the key step in their synthesis from glucose and C7-C16-alkanols.
- Petrovic, Zorica,Konstantinovic, Stanimir,Spasojevic, Aleksandra
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p. 132 - 134
(2007/10/03)
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- Ti2O/SO42-, a convenient and efficient catalyst for desilylation-acetylation of trimethylsilyl ethers with acetic anhydride
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A rapid method for desilylation-acetylation of trimethylsilyl ethers with acetic anhydride catalysed by Ti2O/SO42- at room temperature is reported.
- Jin, Tong-Shou,Li, Yan-Wei,Sun, Guang,Li, Tong-Shuang
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- Silica gel-supported phosphotungstic acid (PTA) catalysed acylation of alcohols and phenols with acetic anhydride under mild reaction conditionst
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Phosphotungstic acid, which is commercially available, practically and efficiently catalyses the acylation of a series of alcohols and phenols with acetic anhydride at room temperature of at refluxing temperature.
- Jin, Tong-Shou,Xiao, Jin-Chong,Wang, Zhen-Hua,Li, Tong-Shuang
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p. 412 - 414
(2007/10/03)
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- Synthesis of C7-C16-alkyl glycosides: Part III - Synthesis of alkyl D-galactopyranosides in the presence of tin(IV) chloride as a Lewis acid catalyst
-
The Lewis acid catalyzed glycosylation reaction of β-peracetylated sugar derivative (galactose) with fatty alkanols is used in a synthesis of C7-C16-alkyl galactopyranosides. The process occurs under the influence of tin(IV) chloride as a Lewis acid catalyst.
- Konstantinovi?,Dimitrijevi?,Radulovi?
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p. 598 - 603
(2007/10/03)
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- Efficient and selective conversion of trimethylsilyl and tetrahydropyranyl ethers to their corresponding acetates and benzoates catalyzed by bismuth(III) salts
-
A variety of TMS and THP ethers are efficiently converted to their corresponding acetates and benzoates with acetic and benzoic anhydrides in the presence of catalytic amounts of Bi(III) salts such as BiCl3, Bi(TFA)3, and Bi(OTf)sub
- Mohammadpoor-Baltork, Iraj,Khosropour, Ahmad R.
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p. 189 - 193
(2007/10/03)
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- Catalytic acetylation of alcohols and phenols with potassium dodecatungstocobaltate trihydrate
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Alcohols and phenols are converted to esters in a mild, clean, and efficient reaction with acetic anhydride in the presence of a catalytic amount of potassium dodecatungstocobaltate trihydrate (K5CoW12O40· 3H2O).
- Habibi, Mohammad H.,Tangestaninejad, Shahram,Mirkhani, Valiollah,Yadollahi, Bahram
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p. 323 - 327
(2007/10/03)
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- Rapid and efficient acetylation of alcohols and phenols with acetic anhydride using tin(IV) porphyrin as catalyst
-
The efficient and rapid esterification of alcohols and phenols in acetic anhydride was achieved by tin(IV) tetraphenylporphyrin perchlorate [SnIV (tpp) (ClO4)2] as catalyst in high yields. SnIV (tpp) (ClO4)2 showed highly catalytic activity on the acetylation reaction.
- Tangestaninejad, Shahram,Habibi, Mohammad Hossein,Mirkhani, Valiollah,Moghadam, Majid
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p. 1337 - 1343
(2007/10/03)
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- Cobalt polyoxometalate, CoW12O405- as a new reusable catalyst for the direct, fast, and efficient acetylation of alcohols and phenols under solventless conditions
-
Alcohols and phenols were efficiently acetylated with acetic anhydride without solvent in the presence of 0.01 molar equiv. of cobalt polyoxometalate (CoW12O405-).
- Habibi,Tangestaninejad,Mirkhani,Yadollahi
-
p. 863 - 867
(2007/10/03)
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- Bismuth(III) salts as convenient and efficient catalysts for the selective acetylation and benzoylation of alcohols and phenols
-
Efficient acetylation and benzoylation of alcohols and phenols with acetic and benzoic anhydrides have been carried out under catalysis of bismuth(III) salts including BiCl3, Bi(TFA)3 and Bi(OTf)3. Selective acetylation and benzoylation of alcohols in the presence of phenols is an additional advantage of this procedure.
- Mohammadpoor-Baltork, Iraj,Aliyan, Hamid,Reza Khosropour, Ahmad
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p. 5851 - 5854
(2007/10/03)
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- Novel catalytic acetylation and formylation of alcohols with potassium dodecatungstocobaltate trihydrate (K5CoW12O40·3H2O)
-
Acetylation and formylation reactions of alcohols with ethyl acetate, acetic acid and ethyl formate were catalyzed with potassium dodecatungstocobaltate trihydrate (K5CoW12O40·3H2O) in a mild, efficient and convenient method with high to excellent yields.
- Habibi, Mohammad H,Tangestaninejad, Shahram,Mirkhani, Valiollah,Yadollahi, Bahram
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p. 8333 - 8337
(2007/10/03)
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- A convenient and chemoselective acetylation and formylation of alcohols and phenols using acetic acid and ethyl formate in the presence of Bi(III) salts
-
A variety of alcohols are acetylated and formylated efficiently with acetic acid and ethyl formate in the presence of catalytic amounts of Bi(III) salts such as BiCl3, Bi(TFA)3 and Bi(OTf)3. BiCl3 and Bi(OTf)3 are also effective catalysts for acetylation of phenols. All of these catalysts are ineffective in formylation of phenols. Selective acetylation and formylation of alcohols in the presence of phenols is an additional advantage of this procedure.
- Mohammadpoor-Baltork,Khosropour,Aliyan
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p. 280 - 282
(2007/10/03)
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- Desilylation-acetylation of trimethylsilyl ethers with acetic anhydride catalysed by montmorillonite K-10
-
Two mild and simple one-step desilylation-acetylations of a variety of alkyl- and aryl-trimethylsilyl ethers, Me3SiOR(Ar), with acetic anhydride in the presence of montmorillonite K-10 clay are described.
- Movassagh,Lakouraj,Fasihi
-
p. 348 - 349
(2007/10/03)
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- Zeolite HSZ-360 as a new reusable catalyst for the direct acetylation of alcohols and phenols under solventless conditions
-
Alcohols and phenols were efficiently acylated with acetic anhydride without solvent over zeolite HSZ-360. The catalyst can be reused with no activity loss.
- Ballini, Roberto,Bosica, Giovanna,Carloni, Silvia,Ciaralli, Lara,Maggi, Raimondo,Sartori, Giovanni
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p. 6049 - 6052
(2007/10/03)
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- HOF·CH3CN, made directly from F2 and water, as an ecologically friendly oxidizing reagent
-
The complex HOF·CH3CN, made directly from fluorine and aqueous acetonitrile, was used for oxidation of secondary alcohols and for Baeyer Villiger oxidation of ketones. By using 18O labeled reagent it was found that the ketone oxidation proceeds through the original dioxirane mechanism which Baeyer and Villiger suggested a century ago for reactions with peracids but was later discounted.
- Rozen, Shlomo,Bareket, Yifat,Kol, Moshe
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p. 8169 - 8178
(2007/10/02)
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- A PROCEDURE FOR ALCOHOL INVERSION USING CESIUM ACETATE
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A convenient and efficient procedure for alcohol inversion by means of the reaction of mesylates or alkyl halides with cesium acetate is described.
- Huffman, John W.,Desai, Ranjit C.
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p. 553 - 558
(2007/10/02)
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- Acid-induced 13C Nuclear Magnetic Resonance Chemical Shift Changes of Ether and Ester Carbon Atoms
-
13C N.m.r. chemical shifts of ehters dissolved in tetrachloromethane are displaced on addition of trifluoroacetic acid.The displacements result from independent interactions of the acid with the substrate oxygen atoms and alkyl residues.The structure-dependent and stereoselective shift changes are useful for signal assignments, structure determination, conformational analysis, assessment of the distribution of rapidly interconverting conformers of esters, and estimation of the relative basicity of ethers.
- Begtrup, Mikael
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p. 1609 - 1618
(2007/10/02)
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- OXIDATION OF N-ALKYL-N'-TOSYLHYDRAZINES WITH Hg(OAc)2. A NEW SYNTHESIS OF ETHERS
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N-Alkyl-N'-tosylhydrazines with Hg(OAc)2 in the presence of alcohols or phenol give high yields of corresponding ethers.Reactions in the presence of acetic acid are also examined.
- Gasparrini, F.,Caglioti, L.,Misiti, D.,Palmieri, G.,Ballini,R.
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p. 3609 - 3613
(2007/10/02)
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