- Trimethylsilyl Esters as Novel Dual-Purpose Protecting Reagents
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Trimethylsilyl esters, AcOTMS, BzOTMS, TCAOTMS, etc., are inexpensive and chemically stable reagents that pose a negligible environmental hazard. Such compounds prove to serve as efficient dualpurpose reagents to respectively achieve acylation and trimethylsilylation of alcohols under acidic or basic conditions. Herein, a detailed study on protection of various substrates and new methodological investigations is described.
- Chang, Ting-Shuo,Chen, Jyun-Siao,Hsieh, Ya-Chi,Hsu, Hsiao-Lin,Huang, Po-Hsun,Liu, Jen-Wei,Liu, Yu-Hao,Luo, Shun-Yuan,Wu, Hsin-Ru,Wu, Ren-Tsung,Zhang, Kai-Min
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supporting information
(2021/12/02)
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- Ethyl acetate as an acetyl surrogate for the iodine catalyzed acetylation of alcohols
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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
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supporting information
p. 4312 - 4315
(2017/10/13)
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- Sustainable Method for the Large-Scale Preparation of Fe3O4 Nanocrystals
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In this work, a facile synthetic process is reported for the large-scale synthesis of Fe3O4 nanocrystals. Thermal decomposition of Fe(acac)3 (100 g) in 1-hexadecanol produced Fe3O4 nanocrystals with well-controlled sizes and morphologies. The nanocrystals were spherically shaped with average diameters of 7.8 ± 0.6, 6.5 ± 0.4, and 5.9 ± 0.2 nm when prepared at 300°C, 270°C, and 250°C, respectively. Mechanisms of crystal formation were elucidated on the basis of gas chromatography-mass spectroscopy analysis, enabling the large-scale preparation of Fe3O4 nanocrystals. To provide an environmentally benign route, Fe3O4 nanocrystals were prepared with recycled solvent which was recovered from the initial experiment. The resulting porous Fe3O4 nanocrystals had larger average sizes than those of the initial nanocrystals. Structural characterization was performed using transmission electron microscopy and powder X-ray diffraction.
- Lee, SungWoo,Yoon, Jae-Sik,Kang, Sungkyoung,Kwon, Kihyun,Chang, Ki Soo,Lee, SangGap,Choi, Sang-Il,Jeong, Jong-Ryul,Lee, Gaehang,Nam, Ki Min,Davies
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p. 2578 - 2584
(2016/08/05)
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- Hydrophobicity-enhanced magnetic solid sulfonic acid: A simple approach to improve the mass transfer of reaction partners on the surface of the heterogeneous catalyst in water-generating reactions
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Two novel and environmentally benign organosulfonic acid-functionalized silica-coated magnetic nanoparticle catalysts 1 (Fe3O 4@SiO2@Et-PhSO3H) and 2 (Fe3O 4@SiO2@Me&Et-PhSO3H) were prepared and their surface hydrophobicity was assessed by esterification reaction of fatty alcohols. Also, their water-toleration in two water-generating reactions was investigated, namely: synthesis of bis(indolyl)methane and the Biginelli reaction of benzaldehyde, methyl acetoacetate, and urea under solvent-free conditions. In these reactions, the catalyst 2 that was more hydrophobic and water-resistant showed higher catalytic activity and was characterized extensively by various techniques. This catalyst was successfully used in the Biginelli reaction of a series of aldehydes, β-keto esters, and urea/thiourea for the synthesis of a diverse range of pharmacologically active 3,4-dihydropyrimidin-2-one/thione (DHPM) derivatives. The catalyst 2 was easily separated by an external magnet and the recovered catalyst was reused in five cycles without any significant loss of activity.
- Mobaraki, Akbar,Movassagh, Barahman,Karimi, Babak
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p. 123 - 133
(2014/01/23)
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- In situ generated Ph3P(OAc)2as a novel reagent for the efficient acetylation of alcohols and thiols at room temperature
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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
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p. 1813 - 1816
(2013/04/24)
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- Synthesis, characterization and application of poly(4-vinylpyridine)- supported Bronsted acid as reusable catalyst for acetylation reaction
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Poly(4-vinylpyridine)-supported Bronsted acids (P4VP-HX) were prepared by wet impregnation technique. These supported acids were found as efficient heterogeneous green catalysts for acetylation of alcohol, amine and phenol with different catalytic activities. The wide application of P4VP-HX as reusable solid acid catalyst in organic reactions is possible because of its simple preparation and handling, stability, simple work up procedure.
- Borah, Kalyan Jyoti,Dutta, Papia,Borah, Ruli
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experimental part
p. 225 - 228
(2011/11/06)
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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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- Separation, recovery and reuse of N-heterocyclic carbene catalysts in transesterification reactions
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A novel and convenient strategy to separate, recover and reuse N-heterocyclic carbene catalysts in transesterification reactions has been developed.
- Zeng, Tieqiang,Song, Gonghua,Li, Chao-Jun
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supporting information; experimental part
p. 6249 - 6251
(2010/02/16)
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- Dual behavior of alcohols in iodine-catalyzed esterification under solvent-free reaction conditions
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The dual behavior phenomenon of alcohols in iodine-catalyzed esterification under solvent-free reaction conditions (SFRCs) is described; the governing factor is the stability of the carbonium ion generated from the alcohol; high concentration reaction conditions (HCRCs) or dilute solutions are much less suitable. In the case of benzylic alcohols, loss of optical activity was noted, whereas alkyl alcohols furnished a product with retention of stereochemistry.
- Jereb, Marjan,Vra?i?, Dejan,Zupan, Marko
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scheme or table
p. 2347 - 2352
(2009/09/06)
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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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- Process for producing esters employing hydrolyzable catalysts
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A process for producing esters wherein a carboxylic acid is reacted with an alcohol in the presence of a hydrolyzable catalyst in an aqueous medium under mixing to produce a reaction mixture comprising an organic phase containing ester and an aqueous phase.
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Page/Page column 6
(2008/06/13)
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- Acetonyltriphenylphosphonium bromide (ATPB): A versatile reagent for the acylation of alcohols, phenols, thiols and amines and for 1,1-diacylation of aldehydes under solvent-free conditions
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A wide variety of alcohols, phenols, amines and thiols may easily be converted into the corresponding acetate derivatives by treatment with acetic anhydride (1.5-2.0 equivalents) in the presence of acetonyltriphenylphosphonium bromide (ATPB; 5 mol %) in good yields at room temperature. With the same precatalyst, both aliphatic and aromatic aldehydes can also be transformed into the corresponding gemdiacetates under reflux conditions.
- Khan, Abu T.,Choudhury, Lokman H.,Ghosh, Subrata
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p. 2782 - 2787
(2007/10/03)
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- Potassium fluoride assisted selective acetylation of alcohols with acetic acid
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Potassium fluoride promotes the acetylation of primary and secondary alcohols with acetic acid in excellent yield. Phenols are not affected under this reaction conditions. The groups like double bond, chloro, methoxy, benzyloxy, thiol, and nitro remain unaffected.
- Bosco, J. W. John,Raju, B. Rama,Saikia, Anil K.
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p. 2849 - 2855
(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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- Esters, retroesters, and a retroamide of palmitic acid: Pool for the first selective inhibitors of N-palmitoylethanolamine-selective acid amidase
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Cyclohexyl hexadecanoate, hexadecyl propionate, and N-(3-hydroxypropionyl)pentadecanamide, respectively ester, retroester, and retroamide derivatives of N-palmitoylethanolamine, represent the first selective inhibitors of "N-palmitoylethanolamine hydrolase" described so far. These compounds are devoid of affinity for CB1 and CB 2 receptors and characterized by high percentages of inhibition of N-palmitoylethanolamine-selective acid amidase (84.0, 70.5, and 76.7% inhibition at 100 μM, respectively) with much lower inhibitory effect on either fatty acid amide hydrolase or the uptake of anandamide.
- Vandevoorde, Séverine,Tsuboi, Kazuhito,Ueda, Natsuo,Jonsson, Kent-Olov,Fowler, Christopher J.,Lambert, Didier M.
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p. 4373 - 4376
(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
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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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- Reptilian chemistry: volatile compounds from paracloacal glands of the American crocodile (Crocodylus acutus).
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The secretion of the paracloacal glands of the American crocodile (Crocodylus acutus) contains over 80 lipophilic compounds, including saturated and unsaturated long-chain alcohols along with their formic, acetic, and butyric acid esters, and several isoprenoids. Most of these compounds were identified on the basis of mass spectra, obtained by GC-MS. In addition, identification of the major components was supported by infrared spectra obtained by GC-FTIR. Major differences are indicated in the composition of the paracloacal gland secretion of C. acutus and that of another crocodylid, the African dwarf crocodile (Osteolaemus tetraspis).
- Garcia-Rubio, Silvina,Attygalle, Athula B,Weldon, Paul J,Meinwald, Jerrold
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p. 769 - 781
(2007/10/03)
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- Highly selective acylation of alcohols and amines by an indium triiodide-catalysed transesterification process
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A very simple method has been developed for the acylation of alcohols and amines by ethyl acetate through an indium triiodide-catalysed transesterification process. Using this method acylation of a primary OH group in the presence of secondary and phenolic OH groups, and of a primary NH2 in the presence of secondary NH and primary OH have been achieved with high selectivity. The Royal Society of Chemistry 2000.
- Ranu, Brindaban C.,Dutta, Pinak,Sarkar, Arunkanti
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p. 2223 - 2225
(2007/10/03)
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- Acetylation and formylation of alcohols with triphenylphosphine and carbon tetrabromide in ethyl acetate or ethyl formate
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Alcohols were acetylated or formylated with triphenylphosphine and carbon tetrabromide in ethyl acetate or ethyl (or methyl) formate at room temperature. THP or TBDMS ether of primary alcohol got converted into formate or acetate under the experimental conditions employed in one pot operation.
- Hagiwara, Hisahiro,Morohashi, Kimie,Sakai, Hitoshi,Suzuki, Toshio,Ando, Masayoshi
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p. 5845 - 5852
(2007/10/03)
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- Iodine as an Acetyl Transfer Catalyst
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Iodine catalyses the acetylation of amines, phenols and alcohols, including tertiary ones, with acetic anhydride in excellent yield.
- Borah, Ruli,Deka, Nabajyoti,Sarma, Jadab C.
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p. 110 - 111
(2007/10/03)
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- Alkylation of potassium acetate in "dry media" thermal activation in commercial microwave ovens
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Microwave irradiation using commercial domestic ovens is very efficient to activate potassium acetate on alumina in the absence of solvent ("dry media") giving rise to remarkable rate enhancements in alkylation reactions with long chain halides. These reactions can be performed quantitatively on appreciable amounts of materials in open standard pyrex vessels.
- Bram, Georges,Loupy, Andre,Majdoub, Mustapha,Gutierrez, Elvira,Ruiz-Hitzsky, Eduardo
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p. 5167 - 5176
(2007/10/02)
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- Acetyl transfer reactions on AlPO4-Al2O3
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An efficient acetylation of alcohols and aliphatic amines promoted by the AlPO4-Al2O3/ethyl acetate system is described.The solid catalist acts, at least in part, as the acetyl carrier.
- Costa, Antonio,Riego, Juan Martin
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p. 2327 - 2328
(2007/10/02)
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- ALKYLATIONS EN ABSENCE DE SOLVANT ORGANIQUE. EFFETS D'ADDITION D'OXYDES MINERAUX ET DE SELS D'AMMONIUM - II. PREPARATION AISEE D'ESTERS PAR ALKYLATION DE L'ANION ACETATE DANS DES CONDITIONS DOUCES ET ECONOMIQUES
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Allyl, benzyl, n-butyl, n-octyl and cetyl acetates are obtained in very good yields (>=92percent) at room temperature by reacting finely-ground CH3COOK and the corresponding alkyl bromide without any solvent and in the presence of catalytic amounts of tetra-alkyl ammonium salts (NBu4Br or Aliquat 336).Effects of addition of mineral oxides have been studied: catalytic effects due to small quantities of TiO2, ZrO2, talc, glass dust and Celite, inhibition effects by large amounts of these solids or their highly hydroxylated analogues (alumina and silica gel).
- Barry, J.,Bram, G.,Decodts, G.,Loupy, A.,Pigeon, P.,Sansoulet, J.
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p. 2673 - 2677
(2007/10/02)
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- A NEW METHOD FOR CLEAVING METHYL AND METHYLTHIOMETHYL ETHERS
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Chlorotrimethylsilane (CTMS) and acetic anhydride has been shown to cleave methyl and methylthiomethyl ethers to furnish the corresponding acetates in excellent yield.Tertiary alcohols can be acetylated efficiently with this reagent combination.
- Barua, Nabin C.,Sharma, Ram P.,Baruah, Jogendra N.
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p. 1189 - 1190
(2007/10/02)
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- EASY AND EFFICIENT ANION ALKYLATIONS IN SOLID-LIQUID PTC CONDITIONS
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Alkylation of anionic nucleophiles such as potassium acetate or potassium indole can be achieved in good yields without solvent either in the presence of NBu4Br and small amounts of TiO2 or in the presence of Aliquat 336 (Oct3MeN(1+)Cl(1-)).
- Barry, J.,Bram, G.,Decodts, G.,Loupy, A.,Pigeon, P.,Sansoulet, J.
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p. 5407 - 5408
(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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