- Synthesis, structure and reactivity of hydrated and dehydrated organotin cations
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Monomeric organotin dications {[nBu2Sn(H2O) 4]2+· 2C6H5SO 3-} and {[nBu2Sn(H2O) 4]2+·1,5-C10H6(SO 3-)2} have been synthesized by the reaction of [nBu2SnO]n and the corresponding arylsulfonic acid. Dodecanuclear organooxotin macrocations {[(nBuSn)12(μ3- O)14(μ2-OH)6]2+·2RSO 3-} (R = C6H5; 2,5-Me 2C6H3) have been synthesized by the reaction of nBuSn(O)(OH) and the corresponding arylsulfonic acid. The X-ray crystal structure of one of the dodecanuclear cages is reported. These organotin cations have been shown to be effective catalysts in acetylation and transacetylation reactions. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Chandrasekhar, Vadapalli,Boomishankar, Ramamoorthy,Gopal, Kandasamy,Sasikumar, Palani,Singh, Puja,Steiner, Alexander,Zacchini, Stefano
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- A novel synthesis of 1,3-diol diesters by the reaction of aldehydes with oxime esters catalyzed by samarium complex
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Cp*2Sm(thf)2 was found to be an efficient catalyst for the synthesis of 1,3-diol diesters by the coupling reaction of aldehydes with oxime esters under mild conditions. For instance, the reaction of acetaldehyde with cyclohexanone oxime acetate catalyzed by Cp*2Sm(thf)2 gave 1,3-diacetoxybutane in 70% yield. Treatment of acetaldehyde with isopropenyl acetate in the presence of a small amount of cyclohexanone oxime acetate and Cp*2Sm(thf)2 resulted in the corresponding 1,3-diol diester in good yield.
- Kawasaki, Yumi,Tashiro, Daisuke,Sakaguchi, Satoshi,Ishii, Yasutaka
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- Method for preparing amino alcohol derivative
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The invention provides a method for preparing an amino alcohol derivative. The method is characterized in that substitution reaction is carried out on ester groups of dihydric alcohol carboxylic esteror polyhydric alcohol carboxylic ester to obtain the amino alcohol derivative, wherein the amidogen is derived into sulfonamido, and at least one carboxylic ester group remains. The method for preparing the amino alcohol derivative has the advantages that the raw materials are cheap and obtained easily, the use quantity of catalysts is low, the reaction condition is simple, and the selectivity ofproducts is high.
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Paragraph 0108; 0109; 0110
(2018/11/22)
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- Sulfonic acid-functionalized periodic mesoporous organosilicas in esterification and selective acylation reactions
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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
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p. 3624 - 3631
(2015/07/01)
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- Simple and practical method for selective acylation of primary hydroxy group catalyzed by N-methyl-2-phenylimidazole (Ph-NMI) or 2-phenylimidazo[2,1-b]benzothiazoles (Ph-IBT)
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N-Methyl-2-phenylimidazole (Ph-NMI) and 2-phenylimidazo[2,1-b]benzothiazoles (Ph-IBT) catalyzed selective acylation of primary alcohols using acid anhydrides. The Ph-NMI- or Ph-IBT-catalyzed reaction using (PhCO)2O as an acylating agent could particularly acylate the primary hydroxy group of 1,n-diols (n ≥ 3) with a high, synthetically useful selectivity.
- Ibe, Kouta,Hasegawa, Yu-Suke,Shibuno, Misuzu,Shishido, Tsukasa,Sakai, Yuzo,Kosaki, Yu,Susa, Keisuke,Okamoto, Sentaro
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p. 7039 - 7042
(2015/01/08)
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- A highly selective, high-speed, and hydrolysis-free O-acylation in subcritical water in the absence of a catalyst
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(Chemical Equation Presented) Fast and furious: A wide range of alcohols are acylated by acetic anhydride, in the absence of catalyst, in subcritical water in a flow-type microreaction system. The esters are selectively produced in high yields at temperatures of 200 to 250°C. Varying the amount of acetic anhydride added with respect to the alcohols allows the regioselective acylation of one or both hydroxy groups of various dihydroxy compounds (see picture).
- Sato, Masahiro,Matsushima, Keiichiro,Kawanami, Hajime,Ikuhsima, Yutaka
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p. 6284 - 6288
(2008/04/05)
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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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- 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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- Selective acylation of a sterically hindered hydroxyl group of unsymmetrical diols containing a primary hydroxyl group such as 1,5-hexanediol in the presence of silica gel with acetyl chloride
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The selective acetylation of sterically hindered hydroxyl groups of 1,5-hexanediol preadsorbed on silica gel was reported. The relation between the adsorption of the diol on SiO2 and its reactivity for selective acetylation was studied. Results demonstrated that unsymmetrical diols get adsorbed on the surface of SiO2 preferentially via a primary OH group, leaving the non-adsorbed OH group available for reaction.
- Ogawa, Haruo,Ide, Yuko,Honda, Ryoichi,Chihara, Teiji
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p. 355 - 358
(2007/10/03)
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- Electrostatic catalysis by ionic aggregates: Scope and limitations of Mg(ClO4)2 as acylation catalyst
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Alkali and alkaline earth metal perchlorates exhibit electrostatic catalysis in the activation of anhydrides for the acylation reaction. Perchlorates with higher values of the charge-size function of the metal ion exhibit better catalytic activity following the order Mg(ClO4) 2>Ba(ClO4)2>LiClO4. Acylation of structurally diverse phenols, thiols, alcohols, and amines have been carried out with stoichiometric amounts of anhydride at room temperature under solvent free conditions in the presence of catalytic amount of Mg(ClO4) 2. Sterically hindered and electron deficient phenols are efficiently acylated. Acylation with sterically hindered anhydrides such as iso-butyric, pivalic, and benzoic anhydrides are carried out with phenols and alcohols in excellent yields. Acid-sensitive alcohols are acylated in excellent yields without any competitive side reactions.
- Chakraborti, Asit K.,Sharma, Lalima,Gulhane, Rajesh,Shivani
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p. 7661 - 7668
(2007/10/03)
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- Lewis acid catalyzed acylation reactions: Scope and limitations
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Acylation of alcohols, thiols, and sugars were studied with a variety of Lewis acids, and it was found that Cu- and Sn(OTf)2 are very efficient in catalyzing the reaction under mild conditions. Among these two catalysts, Cu(OTf)2 was preferred because of its lower cost and relatively higher yield of the acylated product. The reaction was studied in several solvents, but CH2Cl2 was preferred. It was also observed that the present method is suitable for acylation of tertiary alcohols. Sugars were also acylated without any epimerization at the anomeric center. It is further shown here that this method is also suitable for selective acylation of primary or secondary alcohols over tertiary ones.
- Chandra, Kusum L,Saravanan,Singh, Rajesh K,Singh, Vinod K
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p. 1369 - 1374
(2007/10/03)
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- KF-Al2O3 is an efficient solid support reagent for the acetylation of amines, alcohols, and phenols. Impeding effect of solvent on the reaction rate
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KF-Al2O3 brings about rapid acetylation of a range of amines, alcohols, and phenols with Ac2O/AcCl. Aliphatic alcohols are acetylated chemoselectively in the presence of phenols. 1° alcohols react several times faster than 2° alcohols. 3° alcohols do not react.
- Yadav, Veejendra K,Ganesh Babu,Mittal, Manish
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p. 7047 - 7051
(2007/10/03)
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- Mild and practical acylation of alcohols with esters or acetic anhydride under distannoxane catalysis
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Distannoxane catalysts effect acylation of alcohols by action of esters and acetic anhydride. In particular, use of enol esters provides an extremely useful method. Primary alcohols are acylated in preference to secondary ones as well as phenol. Both acid- and base-sensitive functional groups remain intact. Especially unique is the discrimination of thio function which is completely tolerant under the present reaction conditions. This method is highly practical since operation is quite simple. Esters and solvents can be used without purification and no inert atmosphere is necessary. The products can be isolated simply by column chromatography or distillation without aqueous workup.
- Orita, Akihiro,Sakamoto, Katsumasa,Hamada, Yuji,Mitsutome, Akihiro,Otera, Junzo
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p. 2899 - 2910
(2007/10/03)
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- Facile acetylation of alcohols, ethers and ketals with catalytic FeCl3 in AcOH
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A simple and efficient protocol for the conversion of alcohols, ethers and ketals to acetates using catalytic FeCl3(5mol%) in AcOH, or AcOH (3eq) in CH2Cl2 in very high yield is reported. A variety of other acids such as CF3CO2H, HCO2H, CH2=CHCO2H, CH3CH2CO2H, CH3(CH2)2CO2H have also been utilised for the acylation of alcohols successfully.
- Sharma,Mahalingam,Nagarajan,Ilangovan,Radhakrishna, Palakodety
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p. 1200 - 1202
(2007/10/03)
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- An Extremely Simple, Convenient and Selective Method for Acetylation Primary Alcohols in the Presence of Secondary Alcohols
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Reaction of primary-secondary diols with acetyl chloride in dichloromethane in the presence of 2,4,6-collidine, N,N-diisopropylethylamine, or 1,2,2,6,6-pentamethylpiperidine (PMP) leads to the corresponding primary monoacetates simply, conveniently, and in good yields.In this way, other acyl chlorides, sulfonyl chlorides, and silyl chlorides in place of acetyl chloride also react with primary hydroxyl group selectively.
- Ishihara, Kazuaki,Kurihara, Hideki,Yamamoto, Hisashi
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p. 3791 - 3793
(2007/10/02)
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- Cobalt(II) Chloride Catalyzed Acylation of Alcohols with Acetic Anhydride: Scope and Mechanism
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Cobalt(II) chloride catalyzes the acetylation of a variety of alcohols with acetic anhydride in excellent yield.Primary hydroxyl groups can be selectively acylated in the presence of secondary and tertiary ones while the secondary hydroxyl groups can be preferentially acetylated in the presence of tertiary ones.Tertiary alcohols have been found to give ketones, acetoacetates, olefins, and diketene in addition to the acetate.The β-hydroxy esters and ketones can be acylated under these conditions without any elimination, and this reaction has been compared with 4-(dimethylamino)pyridine (DMAP)-mediated acylations where elimination of the resulting β-acetoxy carbonyl compound is observed.A detailed investigation of the acylation of tertiary alcohols has revealed that these reactions proceed via a tertiary alkoxy radical and ketene.A mechanism for these acylations is proposed by invoking an electron-transfer process.
- Iqbal, Javed,Srivastava, Rajiv Ranjan
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p. 2001 - 2007
(2007/10/02)
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- A New Acylation Catalyst
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Cobalt(II) chloride catalyses the acylation of alcohols and amines with anhydrides in excellent yields.
- Ahmad, Saeed,Iqbal, Javed
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p. 114 - 115
(2007/10/02)
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- Reactions of Tin Tetraacetate with Glycols
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The reactions of tin tetraacetate with different glycols, G(OH)2 in equimolar ratio lead to the formation of an insoluble polymeric solid which corresponds mainly to the formula along with a small amount of the corresponding glycol diacetate (AcOGOAc).The reactions in 1:2 molar ratio yield insoluble polymers corresponding to .The reaction of tin tetraacetate with pinacol, on the other hand, yields tin diacetate monopinacolate and tin dipinacolate respectively.
- Vasanta, E.N.,Srivastava, G.,Mehrotra, R. C.
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p. 983 - 984
(2007/10/02)
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