- Pd-Catalyzed solvent-controlled site-selective arene C-H monoacyloxylation of pyrrolo[2,3-d]pyrimidine derivatives
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An efficient and highly regioselective Pd-catalyzed direct arene C(sp2)-H acyloxylation of pyrrolo[2,3-d]pyrimidine derivatives is reported. The key strategy involves the utilization of the unique reactivity of pyrrolo[2,3-d]pyrimidine and the employment of pyrrolo[2,3-d]pyrimidine as the directing group. A variety of monoacyloxylated pyrrolo[2,3-d]pyrimidine derivatives can be achieved by switching the solvents under mild conditions, and they can be further modified and exhibit various biological activities.
- Jiang, Yunfeng,Liu, Min,Mao, Zhengtong,Qian, Hongjie,Zhang, Xingxian
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supporting information
p. 8591 - 8596
(2021/10/20)
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- Iodide as an activating agent for acid chlorides in acylation reactions
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Acid chlorides can be activated using a simple iodide source to undergo nucleophilic attack from a variety of relatively weak nucleophiles. These include Friedel-Crafts acylation of N-methylpyrroles, N-acylation of sulfonamides, and acylation reactions of hindered phenol derivatives. The reaction is believed to proceed through a transient acid iodide intermediate.
- Wakeham, Russell J.,Taylor, James E.,Bull, Steven D.,Morris, James A.,Williams, Jonathan M. J.
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supporting information
p. 702 - 705
(2013/04/11)
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- Copper(II) Tetrafluoroborate-Catalyzed Acetylation of Phenols, Thiols, Alcohols, and Amines
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Copper(II) tetrafluoroborate efficiently catalyzes acetylation of structurally diverse phenols, alcohols, thiols, and amines with stoichiometric amounts of Ac2O under solvent-free conditions at room temperature. Acid-sensitive alcohols are smoothly acetylated without competitive side reactions. The reaction is influenced by the steric and electronic factors associated with the substrate as well as the anhydride. Acetylation of a sterically hindered substrate requires excess of anhydride and longer time. Acylation with less electrophilic anhydrides affords poor to moderate yields.
- Chakraborti, Asit K.,Gulhane, Rajesh,Shivani
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p. 111 - 115
(2007/10/03)
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- Zirconiuni(IV) chloride as a new, highly efficient, and reusable catalyst for acetylation of phenols, thiols, amines, and alcohols under solvent-free conditions
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Zirconium(IV) chloride has been found to be a new, highly efficient, and reusable catalyst for acetylation of structurally diverse phenols, thiols, amines, and alcohols under solvent-free condtions. Acetylation of sterically hindered and electron deficient phenols is achieved in excellent yields with stoichiometric amounts of Ac2O at room temperature. Acid-sensitive alcohols undergo acetylation with excellent chemoselectivity without competitive side reactions such as dehydration or rearrangement. The mild Lewis acid property of the catalyst enables the acetylation to be carried out with optically active substrates without any detrimental effect on the optical purity.
- Chakraborti, Asit K.,Gulhane, Rajesh
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p. 627 - 630
(2007/10/03)
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- Erbium(III) triflate as an extremely active acylation catalyst
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Erbium(III) triflate is a powerful catalyst for the acylation of alcohols and phenols. The reaction works well for a large variety of simple and functionalized substrates by using different kinds of acidic anhydrides {Ac 2O, (EtCO)2O, [(CH3)3CO] 2O, Bz2O, and (CF3CO)2O} without isomerisation of chiral centres. Moreover, the catalyst can be easily recycled and reused without significant loss of activity.
- Procopio, Antonio,Dalpozzo, Renato,De Nino, Antonio,Maiuolo, Loredana,Russo, Beatrice,Sindona, Giovanni
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p. 1465 - 1470
(2007/10/03)
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- Perchloric acid adsorbed on silica gel as a new, highly efficient, and versatile catalyst for acetylation of phenols, thiols, alcohols, and amines
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Perchloric acid adsorbed on silica gel efficiently catalyses acetylation of structurally diverse phenols, alcohols, thiols, and amines under solvent free conditions.
- Chakraborti, Asit K.,Gulhane, Rajesh
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p. 1896 - 1897
(2007/10/03)
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- Highly efficient and versatile acetylation of alcohols catalyzed by cerium(III) triflate
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Cerium(III) triflate is a powerful catalyst for the acetylation of alcohols. The reaction works well for a large variety of simple and functionalized alcohols, without isomerisation of chiral centres. Changes of hydroxyl protective groups are possible in a one-pot procedure. The catalyst can be easily recycled.
- Dalpozzo, Renato,De Nino, Antonio,Maiuolo, Loredana,Procopio, Antonio,Nardi, Monica,Bartoli, Giuseppe,Romeo, Roberto
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p. 5621 - 5624
(2007/10/03)
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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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- 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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- Indium(III) chloride as a new, highly efficient, and versatile catalyst for acylation of phenols, thiols, alcohols, and amines
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Indium(III) chloride efficiently catalyses the acylation of structurally diverse phenols, alcohols, thiols, and amines under solvent free conditions. Acid sensitive alcohols are smoothly acylated without competitive side reactions. Acylation of 2-hydroxynaphthalene is carried out with carboxylic acids adopting the mixed anhydride protocol using trifluoroacetic anhydride.
- Chakraborti, Asit K.,Gulhane, Rajesh
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p. 6749 - 6753
(2007/10/03)
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- Bismuth Oxide Perchlorate as a Highly Efficient Catalyst for Heteroatom Acylation under Solvent-Free Conditions
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Bismuth oxide perchlorate efficiently catalyzes the acetylation of structurally diverse phenols, alcohols, thiols, and amines under solvent free conditions. Sterically hindered and electron deficient phenols are acetylated in excellent yields with stoichiometric amounts of Ac2O at room temperature. Acylation of acid-sensitive alcohols is carried out efficiently without competitive side reactions. Optically active substrates are acetylated without any detrimental effect on the optical purity.
- Chakraborti, Asit K.,Gulhane, Rajesh,Shivani
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p. 1805 - 1808
(2007/10/03)
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- Single-pass reaction column system with super br?nsted acid-loaded resin
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Various acid-promoted reactions gave the desired products in high yields by passing a solution of reactants through a reaction column packed with polystyrene-bound super Br?nsted acid (1) just once. Polar and nonpolar organic solvent-swellable 1 is much superior to Nafion SAC-13 (2) as a Br?nsted acid-loaded resin packed in the column.
- Ishihara, Kazuaki,Hasegawa, Aiko,Yamamoto, Hisashi
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p. 1296 - 1298
(2007/10/03)
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- Magnesium bromide catalysed acylation of alcohols
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Magnesium bromide is an efficient catalyst for the acetylation and benzoylation of a variety of primary and secondary alcohols with the respective acid anhydrides at ambient temperature. Acetylation of tertiary alcohols requires subambient temperature to suppress competing dehydration. Coordinating solvents retard the acylation process.
- Pansare, Sunil V.,Malusare, Mahesh G.,Rai, Anand N.
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p. 2587 - 2592
(2007/10/03)
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- Lanthanide bis[bis(1,1,1,3,3,3-hexafluoro-2-propoxy)sulfonyl]amide as a novel effective acylation catalyst
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Lanthanide complexes Ln(BHFPSA)3 {BHFPSA = N[SO2OCH(CF3)2]2} catalyse the acylation of alcohols or phenols under very mild conditions to afford esters in high yields.
- Nie, Jin,Zhao, Zhongming,Xu, Jun,Liu, Dafan
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p. 160 - 161
(2007/10/03)
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- Scandium trifluoromethanesulfonate as an extremely active Lewis acid catalyst in acylation of alcohols with acid anhydrides and mixed anhydrides
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Scandium trifluoromethanesulfonate (triflate), which is commercially available, is a practical and useful Lewis acid catalyst for acylation of alcohols with acid anhydrides or the esterification of alcohols by carboxylic acids in the presence of p-nitrobenzoic anhydrides. The remarkably high catalytic activity of scandium triflate can be used for assisting the acylation by acid anhydrides of not only primary alcohols but also sterically-hindered secondary or tertiary alcohols. The method presented is especially effective for selective macrolactonization of ω-hydroxy carboxylic acids.
- Ishihara, Kazuaki,Kubota, Manabu,Kurihara, Hideki,Yamamoto, Hisashi
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p. 4560 - 4567
(2007/10/03)
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- Acylation and Esterification of the Aryloxide Ligand in . Crystal Structures of , Hbhmap and O=C(dbmp)But (Hdbmp = 2,6-di-tert-butyl-4-methylphenol, Hbhmap = 3-tert-butyl-2-hydroxy-5-methylacetophenone)
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The reaction of (Hdbmp = 2,6-di-tert-butyl-4-methylphenol) with O=C(Cl)Me leads to acylation of one of the dbmp ligands and affords 1 (Hbhmap = 3-tert-butyl-2-hydroxy-5-methylacetophenone).Hydrolysis of 1 yields uncomplex
- Power, Michael B.,Bott, Simon G.,Bishop, Elizabeth J.,Tierce, Kelli D.,Atwood, Jerry L.,Barron, Andrew R.
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p. 241 - 247
(2007/10/02)
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- SYNTHESIS OF 4-ALKOXY- AND 4-ACYLOXY-2,6-DI-tert-BUTYLPHENOLS AND QUINOL ETHERS BASED ON THEM
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4-Alkoxy- and 4-acyloxy-2,6-di-tert-butylphenols were obtained by the alkylation and acylation of 2,6-di-tert-butyl-p-dihydroxybenzene.With quinone dioximes under oxidizing conditions the products form quinol ethers.
- Dobronravova, Z. A.,Meshcheryakov, V. I.,Prishchenko, Yu. E.,Gavrilov, L. D.,Vereshchagin, L. I.
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p. 910 - 914
(2007/10/02)
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- Acyclic Stereoselection. 9. Stereochemistry of the Addition of Lithium Enolates to α-Alkoxy Aldehydes
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The stereochemistry of addition of lithium enolates derived from esters and ketones to the α-alkoxy aldehydes 1-5 has been investigated.In all cases, the predominant product is that predicted by application of Felkin's model for asymmetric induction and by assuming the alkoxy group to be the "large" group.The Cram cyclic model for asymmetric induction is not followed.Stereostructures have been assigned by a combination of conversion to products of known stereostructure, 13C and 1H NMR correlations, and single-crystal X-ray analysis.
- Heathcock, Clayton H.,Young, Steven D.,Hagen, James P.,Pirrung, Michael C.,White, Charles T.,VanDerveer, Don
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p. 3846 - 3856
(2007/10/02)
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