- Tropolonate salts as acyl-transfer catalysts under thermal and photochemical conditions: Reaction scope and mechanistic insights
-
Acyl-transfer catalysis is a frequently used tool to promote the formation of carboxylic acid derivatives, which are important synthetic precursors and target compounds in organic synthesis. However, there have been only a few structural motifs known to efficiently catalyze the acyl-transfer reaction. Herein, we introduce a different acyl-transfer catalytic paradigm based on the tropolone framework. We show that tropolonate salts, due to their strong nucleophilicity and photochemical activity, can promote the coupling reaction between alcohols and carboxylic acid anhydrides or chlorides to give products under thermal or blue light photochemical conditions. Kinetic studies and density functional theory calculations suggest interesting mechanistic insights for reactions promoted by this acyl-transfer catalytic system.
- Mai, Binh Khanh,Koenigs, Rene M.,Nguyen, Thanh Vinh,Lyons, Demelza J.M.,Empel, Claire,Pace, Domenic P.,Dinh, An H.
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p. 12596 - 12606
(2020/11/18)
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- Divergent Late-Stage (Hetero)aryl C?H Amination by the Pyridinium Radical Cation
-
(Hetero)arylamines constitute some of the most prevalent functional molecules, especially as pharmaceuticals. However, structurally complex aromatics currently cannot be converted into arylamines, so instead, each product isomer must be assembled through a multistep synthesis from simpler building blocks. Herein, we describe a late-stage aryl C?H amination reaction for the synthesis of complex primary arylamines that other reactions cannot access directly. We show and rationalize through a mechanistic analysis the reasons for the wide substrate scope and the constitutional diversity of the reaction, which gives access to molecules that would not have been readily available otherwise.
- Ham, Won Seok,Hillenbrand, Julius,Jacq, Jér?me,Genicot, Christophe,Ritter, Tobias
-
supporting information
p. 532 - 536
(2019/01/04)
-
- Biogenic CuFe2O4 magnetic nanoparticles as a green, reusable and excellent nanocatalyst for acetylation reactions under solvent-free conditions
-
A convenient green method has been developed for the synthesis of biogenic CuFe2O4 magnetic nanoparticles using tea extracts within a very short reaction time. The prepared nanoparticles with an average size of 8.78 nm have been used as an effective catalyst for the acetylation of various alcohols, phenols and amines in good to excellent yields under solvent-free conditions. The catalyst was characterized by XRD, XPS, VSM, SEM and TEM study. A magnetic study of the fresh and recycled catalyst after the fourth cycle was performed by VSM measurement. The main advantages of this protocol are simple biogenic synthesis of the catalyst, a reusable and heterogeneous catalytic system, and short reaction times with excellent yields.
- Chutia, Rituparna,Chetia, Bolin
-
p. 15200 - 15206
(2018/09/29)
-
- DMAP-based flexible polymer networks formed via Heck coupling as efficient heterogeneous organocatalysts
-
Two DMAP-based flexible polymer networks TPB-DMAP and TPA-DMAP have been successfully synthesized via palladium catalyzed Heck cross-coupling. The structures of these polymers were confirmed by solid state 13C CP/MAS and Fourier transform infrared spectroscopy (FTIR). Although both polymers have negligible surface areas, they exhibit excellent catalytic efficiency for the acylation of 1-phenylethanol with acetic anhydride due to their good swelling capacities. Utilized as a typical catalyst, the polymer TPA-DMAP shows high activities for acylation of a variety of alcohols to the corresponding esters. Moreover, the catalyst can be recycled at least ten times without obvious loss of catalytic activity.
- Xu, Wei,Xia, Wu,Guan, Yukun,Wang, Yiming,Lu, Cuifen,Yang, Guichun,Nie, Junqi,Chen, Zuxing
-
-
- 2-substituted benzoxazole preparation method of compound
-
The invention relates to a preparing method of 2-substituted benzoxazole compounds. The compounds are obtained by reaction of products obtained by reaction of acyl chloride and o-nitrophenol or derivatives thereof under catalyzing of reducing agent ammonium formate, a solvent and palladium-containing agents. According to the method, the reaction condition is mild, environment is protected, raw materials are rich and easy to obtain, operation is easy, yield is high, and various kinds of performance are optimized.
- -
-
Paragraph 0064
(2016/10/20)
-
- 4-(N,N -dimethylamino)pyridine hydrochloride as a recyclable catalyst for acylation of inert alcohols: Substrate scope and reaction mechanism
-
4-(N,N-Dimethylamino)pyridine hydrochloride (DMAP·HCl), a DMAP salt with the simplest structure, was used as a recyclable catalyst for the acylation of inert alcohols and phenols under base-free conditions. The reaction mechanism was investigated in detail for the first time; DMAP·HCl and the acylating reagent directly formed N-acyl-4-(N′,N′-dimethylamino) pyridine chloride, which was attacked by the nucleophilic substrate to form a transient intermediate that released the acylation product and regenerated the DMAP·HCl catalyst.
- Liu, Zhihui,Ma, Qiaoqiao,Liu, Yuxiu,Wang, Qingmin
-
supporting information
p. 236 - 239
(2014/01/23)
-
- Vitamin B1 supported on silica-encapsulated γ-Fe 2O3 nanoparticles: Design, characterization and application as a greener biocatalyst for highly efficient acylation
-
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
-
p. 8812 - 8816
(2014/03/21)
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- Acetylation of alcohols and phenols by zinc zirconium phosphate as an efficient heterogeneous catalyst under solvent-free conditions
-
An efficient method for the acetylation of a wide range of alcohols as well as phenols with acetic anhydride in good to excellent yields under solvent-free conditions, using zinc zirconium phosphate as the catalyst was investigated. The catalyst was characterized by XRD, inductivity coupled plasma-optical emission spectroscopy, and scanning electron microscope. Products are easily isolated and the protocol is mild and green, compared to the existing methods. Graphical abstract: [Figure not available: see fulltext.]
- Hajipour, Abdol Reza,Karimi, Hirbod,Karimzadeh, Morteza
-
p. 1461 - 1472
(2014/09/30)
-
- Lewis basic ionic liquid as an efficient and facile catalyst for acetylation of alcohols, phenols, and amines under solvent-free conditions
-
The Lewis basic ionic liquid 1,8-diazabicyclo[5.4.0]undec-7-en-8-ium acetate was employed for the acetylation of various phenols, alcohols, and amines in good-to-excellent yields at 50 C under solvent-free conditions in a short time. Compared with existing methods based on conventional catalysts and toxic solvents, the reported method is simple, mild and environmentally viable. Furthermore, the ionic liquid was conveniently separated from the products and easily recycled to catalyze other acetylation reactions with excellent yields. .
- Ji, Li,Qian, Chao,Chen, Xin-Zhi
-
p. 369 - 374
(2013/05/21)
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- A new ferrocene-based bulky pyridine as an efficient reusable homogeneous catalyst
-
An effective approach to reusing a homogeneous catalyst has been demonstrated. A ferrocene-based bulky pyridine has been synthesized and utilized as a homogeneous catalyst for the synthesis of benzoylfumarates as well as for acetylation. After the reaction, the catalyst was separated by simple precipitation and reused without appreciable loss of activity. The Royal Society of Chemistry 2013.
- Kashyap, Bishwapran,Phukan, Prodeep
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p. 15327 - 15336
(2013/09/02)
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- In situ generated acylimidazolium acetate as an efficient catalyst and acylating agent for the acetylation of alcohols, phenols, and amines at ambient temperature
-
Acylimidazolium acetate was readily prepared in situ from the reaction of imidazole with acetic anhydride and subsequently acted as a catalyst and acylating agent for the efficient acetylation of alcohols, phenols, and amines at ambient temperature.
- Nowrouzi, Najmeh,Alizadeh, Seyedeh Zahra
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p. 1787 - 1790
(2013/10/21)
-
- Amorphous carbon-silica composites bearing sulfonic acid as solid acid catalysts for the chemoselective protection of aldehydes as 1,1-diacetates and for N-, O- and S-acylations
-
Amorphous carbon-silica composites bearing sulfonic acid derived from inexpensive natural organic compounds (glucose, maltose, cellulose, chitosan and starch) were prepared by partial carbonization followed by sulfonation and their catalytic activity was evaluated for the protection of aldehydes as 1,1-diacetates and for N-, O- and S-acylations under solvent-free conditions. Different biomaterials have been chosen, with a view to select the most active solid acid catalyst. Carbon-silica composites were characterized by FTIR, XRD and elemental analysis. Sulfonated carbon-silica composite derived from starch was found to be the most active and could be recycled for several runs without loss of significant activity. It was also characterized by TGA, SEM and TEM.
- Gupta, Princy,Paul, Satya
-
experimental part
p. 2365 - 2372
(2011/10/31)
-
- 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
-
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
-
experimental part
p. 159 - 164
(2011/12/16)
-
- Iron-doped single-walled carbon nanotubes as new heterogeneous and highly efficient catalyst for acylation of alcohols, phenols, carboxylic acids and amines under solvent-free conditions
-
Iron-doped single-walled carbon nanotubes (Fe/SWCNTs) represent an efficient and new heterogeneous reusable catalyst for the acylation of a variety of alcohols, phenols, carboxylic acids and amines with acid chlorides or acid anhydrides under solvent-free conditions. The reactions of various primary, secondary, tertiary, and benzylic alcohols, diols, phenols, as well as aromatic and aliphatic amines give acylated adducts in good to excellent yields.
- Sharghi, Hashem,Jokar, Mahboubeh,Doroodmand, Mohammad Mahdi
-
experimental part
p. 426 - 442
(2011/04/15)
-
- Comparative study of acetylation of alcohols and phenols with different acetylating agents using zinc chloride as catalyst under solvent free conditions at room temperature
-
Efficient acetylation of 1°, 2° and 3°, benzylic alcohols and phenols under solvent free conditions at room temperature in presence of less toxic, easily available and in-expensive catalyst ZnCl2, using acetic anhydride or acetyl chloride as an acetylating agent. On comparative study of these two acetylating agents, the acetyl chloride seemed to be better acetylating agent.
- Yadav, Prakrati,Lagarkha, Rekha,Balla, Zahoor Ahmad
-
experimental part
p. 5155 - 5158
(2012/07/28)
-
- Simple and efficient method for acetylation of alcohols, phenols, amines, and thiols using anhydrous NiCl2 under solvent-free conditions
-
Solvent-free acetylation of alcohols, phenols, amines, and thiols with acetic anhydride (Ac2O) in the presence of 0.1mol% (13mg) anhydrous NiCl2, an inexpensive and easily available catalyst, is described. Excellent yields, short reaction time, and mild reaction conditions are important features of this method.
- Meshram, Gangadhar,Patil, Vishvanath D.
-
experimental part
p. 4384 - 4395
(2010/04/29)
-
- TiO2: A simple and an efficient catalyst for esterification of phenols under solvent-free condition
-
In the presence of catalytic amount of titanium oxide (TiO2), without any additional solvent at 25°C, phenols are conveniently acylated by acid chlorides to get phenolic esters in excellent yields. The TiO2 powder can be reused three times after simple washing with CH2Cl 2.
- Pasha, Mohamed Afzal,Manjula, Krishnappa
-
p. 597 - 600
(2008/09/19)
-
- Acetylation of some organic compounds under microwave irradiation
-
Acetic acid has been used for acetylation of seven aromatic amines and two phenols under microwave exposure. The time taken for these reactions ranges from 18-25 min with reasonability good yields (65-77%).
- Jain, Deepika,Soni, Murli Dhar,Vardia, Jitendra,Punjabi,Ameta, Suresh C.
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p. 188 - 188
(2008/03/11)
-
- Rapid and efficient method for acetylation of alcohols and phenols with acetic anhydride catalyzed by silica sulfate
-
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
-
p. 1221 - 1227
(2007/10/03)
-
- Magnesium bistrifluoromethanesulfonimide as a new and efficient acylation catalyst
-
Magnesium bistrifluoromethanesulfonimide catalyzed the acetylation of phenols, alcohols, and thiols under solvent-free conditions at room temperature and in short times. Electron-deficient and sterically hindered phenols provided excellent yields. The catalyst was found to be general for acylation with other anhydrides, such as propionic, isobutyric, pivalic, chloroacetic, and benzoic anhydrides. The rate of acylation was influenced by the electronic and steric factors associated with the anhydride. The reaction with less electrophilic anhydrides (e.g., chloroacetic and benzoic anhydrides) required higher temperature (~80 °C). Chemoselective acetylation, pivalation, and benzoylation took place with acid-sensitive alcohols without any competitive dehydration/rearrangement.
- Chakraborti, Asit K.,Shivani
-
p. 5785 - 5788
(2007/10/03)
-
- Nitration of aromatic compounds by Zn(NO3)2· 2N2O4 and its charcoal-supported system
-
Zn(NO3)2·N2O4 and its charcoal supported system were found to be efficient nitrating agents. Mononitration of aromatic compounds such as benzene, alkyl benzenes, halobenzenes, nitrobenzene, anisol, and the highly selective mono-, di-, and trinitration of phenol, and dinitraion of substituted phenols were also performed in the presence of these reagents.
- Iranpoor, Nasser,Firouzabadi, Habib,Heydari, Reza,Shiri, Morteza
-
p. 263 - 270
(2007/10/03)
-
- Facile catalyzed acylation of alcohols, phenols, amines and thiols based on ZrOCl2·8H2O and acetyl chloride in solution and in solvent-free conditions
-
Acylation of heteroatoms (O, N and S) with acetyl chloride based on the use of a catalytic amount of the moisture stable, inexpensive ZrOCl 2?8H2O, proceeds efficiently producing the corresponding acylated products in excellent yields.
- Ghosh, Rina,Maiti, Swarupananda,Chakraborty, Arijit
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p. 147 - 151
(2007/10/03)
-
- Zinc oxide (ZnO) as a new, highly efficient, and reusable catalyst for acylation of alcohols, phenols and amines under solvent free conditions
-
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
-
p. 10903 - 10907
(2007/10/03)
-
- Acetylation of alcohols, phenols, thiols and amines catalysed by H-beta zeolite
-
The acetylation of several alcohols, phenols, thiols and amines was effected at room temperature in excellent yields using H-beta zeolite as catalyst and acetic anhydride as acetylating agent under mostly solvent-free conditions.
- Bhaskar, Pallooru Muni,Loganathan, Duraikkannu
-
p. 892 - 894
(2007/10/03)
-
- Zirconiuni(IV) chloride as a new, highly efficient, and reusable catalyst for acetylation of phenols, thiols, amines, and alcohols under solvent-free conditions
-
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
-
p. 627 - 630
(2007/10/03)
-
- Copper(II) Tetrafluoroborate-Catalyzed Acetylation of Phenols, Thiols, Alcohols, and Amines
-
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
-
p. 111 - 115
(2007/10/03)
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- Facile catalyzed acylation of heteroatoms using BiCl3 generated in situ from the procatalyst BiOCl and acetyl chloride
-
Acylation of a variety of alcohols, phenols, aliphatic and aromatic amines, a thiol and a thiophenol proceeds efficiently using BiCl3 generated in situ from the procatalyst BiOCl and acetyl chloride in a solvent or under solventless conditions, furnishing the corresponding acylated derivatives in very good to excellent yields.
- Ghosh, Rina,Maiti, Swarupananda,Chakraborty, Arijit
-
p. 6775 - 6778
(2007/10/03)
-
- A rapid and efficient method for acetylation of phenols with acetic anhydride catalysed by TiO2/SO42- solid superacid
-
A rapid and efficient method for acetylation of phenols with acetic anhydride in the presence of TiO2/SO42- solid superacid at room or at reflux temperature in excellent yield is described.
- Ma, Yan-Ran,Jin, Tong-Shou,Wang, Zhen-Hua,Li, Tong-Shuang
-
p. 1777 - 1778
(2007/10/03)
-
- Fluoroboric acid adsorbed on silica gel as a new and efficient catalyst for acylation of phenols, thiols, alcohols, and amines
-
Fluoroboric acid supported on silica gel efficiently catalyzes acylation of structurally diverse phenols, alcohols, thiols, and amines under solvent free conditions. Acid-sensitive alcohols are smoothly acylated without competitive side reactions.
- Chakraborti, Asit K.,Gulhane, Rajesh
-
p. 3521 - 3525
(2007/10/03)
-
- Bismuth Oxide Perchlorate as a Highly Efficient Catalyst for Heteroatom Acylation under Solvent-Free Conditions
-
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
-
p. 1805 - 1808
(2007/10/03)
-
- Silica gel-supported phosphotungstic acid (PTA) catalysed acylation of alcohols and phenols with acetic anhydride under mild reaction conditionst
-
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
-
p. 412 - 414
(2007/10/03)
-
- Electrostatic catalysis by ionic aggregates: Scope and limitations of Mg(ClO4)2 as acylation catalyst
-
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
-
p. 7661 - 7668
(2007/10/03)
-
- Ac2O-Py/basic alumina as a versatile reagent for acetylations in solvent-free conditions under microwave irradiation
-
Acetic anhydride-pyridine over basic alumina has been used in order to carry out acetylations of hydroxy, thiol and amino groups in solvent-free conditions under microwave irradiation. The technique can be extended for selective acetylations by regulation of irradiation time.
- Paul, Satya,Nanda, Puja,Gupta, Rajive,Loupy, André
-
p. 4261 - 4265
(2007/10/03)
-
- 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
-
p. 1337 - 1343
(2007/10/03)
-
- 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)
-
- Bi(III) salts as new catalysts for the selective conversion of trimethylsilyl and tetrahydropyranyl ethers to their corresponding acetates and formates
-
Bi(III) salts such as BiCl3, Bi(TFA)3 and Bi(OTf)3 were found to be efficient catalysts for the transformation of trimethylsilyl (TMS) and tetrahydropyranyl (THP) ethers to their corresponding acetates and formates with acetic acid and ethyl formate. Selective acetylation and formylation of TMS and THP ethers of alcohols in the presence of phenolic TMS and THP ethers make this method a useful and practical procedure in organic synthesis.
- Mohammadpoor-Baltork,Khosropour
-
p. 2433 - 2439
(2007/10/03)
-
- 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.
-
p. 189 - 193
(2007/10/03)
-
- An efficient and simple procedure for preparation of esters and anhydrides from acid chlorides in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) under solvent-free conditions
-
A manipulatively one-pot and rapid method for the synthesis of aliphatic and aromatic ester and anhydride from acid chloride and alcohol or potassium salt of carboxylic acid under solvent-free conditions is reported. The reaction has been carried out in excellent yield and short reaction time in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) under solvent-free conditions.
- Hajipour,Mazloumi
-
-
- 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
-
p. 5851 - 5854
(2007/10/03)
-
- 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
-
p. 280 - 282
(2007/10/03)
-
- An efficient and simple procedure for acetylation of alcohols and phenols with acetic anhydride catalysed by expansive graphite
-
Acetylation of alcohols and phenols with acetic anhydride has been carried out in excellent yield under catalysis of expansive graphite.
- Jin, Tong-Shou,Ma, Yan-Ran,Li, Tong-Shuang,Zhang, Zhan-Hui,Duan, Guang-Bo
-
p. 109 - 110
(2007/10/03)
-
- Montmorillonite clay catalysis. Part 10. K-10 and KSF-catalysed acylation of alcohols, phenols, thiols and amines: Scope and limitation
-
Montmorillonite K-10 and KSF are highly efficient catalysts for the acetylation of a variety of alcohols, thiols, phenols and amines with acetic anhydride. Amino groups can be selectively acetylated in the presence of hydroxy groups, while the hydroxy groups can be preferentially acetylated in the presence of thiol groups. No selectivity is observed between primary and secondary hydroxy groups in the presence of K-10 and KSF. The catalysts are found not to be efficient for acetylation of tertiary alcohols. This method is simple and convenient with minimum environmental impact. The catalysts are also effective for the acylation of alcohols, thiols, phenols and amines with acetyl chloride and benzoyl chloride. Cyclic anhydrides such as succinic anhydride, maleic anhydride and phthalic anhydride and p-toluene sulfonyl chloride show less reactivity than acetic anhydride and acyl chlorides.
- Li, Tong-Shuang,Li, Ai-Xiao
-
p. 1913 - 1917
(2007/10/03)
-
- Sulfamic acid catalysed acetylation of alcohols and phenols with acetic anhydride
-
An easy acetylation of alcohols and phenols with acetic anhydride has been carried out in excellent yield under catalysis of sulfamic acid.
- Jin, Tong-Shou,Ma, Van-Ran,Zhang, Zhan-Hui,Li, Tong-Shuang
-
p. 3173 - 3177
(2007/10/03)
-
- Montmorillonite K-10 and KSF as remarkable acetylation catalysts
-
Montmorillonite K-10 and KSF catalyse the acetylation of alcohols, thiols, phenols and amines with acetic anhydride in excellent yield.
- Li, Ai-Xiao,Li, Tong-Shuang,Ding, Tian-Hui
-
p. 1389 - 1390
(2007/10/03)
-
- Ozone-mediated Reaction of Anilides and Phenyl Esters with Nitrogen Dioxide: Enhanced Ortho-reactivity and Mechanistic Implications
-
In the presence of ozone, anilides 1 can be nitrated rapidly with nitrogen dioxide in chloroform at 0 deg C to give a high proportion of ortho-nitro derivatives (ortho:para = 1.2-4.4) in good yields.The phenyl esters 15 can be similarly nitrated on the aromatic ring without significant cleavage of the ester bond, giving a mixture of isomeric nitro derivatives in which the ortho-isomer predominantes (ortho:para = 1.1-1.5).The oridin of the enhanced ortho reactivity is discussed in terms of an electron-transfer process involving the nitrogen trioxide as initial electrophile.
- Suzuki, Hitomi,Tatsumi, Atsuo,Ishibashi, Taro,Mori, Tadashi
-
p. 339 - 344
(2007/10/02)
-
- An Open Transition State in Carbonyl Acyl Group Transfer in Aqueous Solution
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The second-order rate constants have been measured for the reaction of substituted phenolate ions with 2,4-dinitrophenyl acetate, 2,4-dinitrophenyl 4-methoxy-2,6-dimethylbenzoate and acetic anhydride in aqueous solution at 25 deg C.The data are over a wide range of phenolate ion basicity and obey good Broensted equations which have βnuc values of, respectively, 0.57 +/- 0.03, 0.15 +/- 0.07 and 0.59 +/- 0.05.The principal conclusion of this work is that the identity reaction of 2,4-dinitrophenolate ion with 2,4-dinitrophenyl 4-methoxy-2,6-dimethylbenzoate has anopen transition state, namely one with very weak bonds to entering and departing ligands.The transition state possesses a Kreevoy tightness parameter (τ) of 0.18.The open transition state arises from the stabilising effect of the acyl group substituents on the benzoylium ion and their destabilising effect on the putative tetrahedral intermediate as well as the weak basicities of the nucleophile and nucleofuge.This is the first example of an open transition state in an acyl group transfer which does not require the assistance of a negatively charged internal nucleophile.The data for 2,4-dinitrophenyl acetate may be employed to calculate an identity rate constant (kii) for the reaction of 2,4-dinitrophenolate ion with the ester.This data may be fitted to a theoretical Lewis-Kreevoy plot (log kii vs. pKi) possessing both positive and negative values of βii (slope of the line).Microscopic medium effects place a limit to the accuracy of predictions of rate constants, including kii, from linear free energy relationships.
- Ba-Saif, Salem A.,Colthurst, Matthew,Waring, Mark A.,Williams, Andrew
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p. 1901 - 1908
(2007/10/02)
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- A Kinetic Study of the Hydrolysis of Aryl Esters by the pH-Stat Method
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The rates of hydrolysis of a series of aryl acrylates and aryl acetates in water at 24 deg C have been monitored by the pH stat method.The second-order rate coefficients for base-induced reactions (kOH) determined by this method are consistent with literature values determined under buffered conditions and conform to the conventional BAC2 mechanism for ester hydrolysis.
- Marsh, Mary Rose,Gold, Victor,Hall, C. Dennis,Sghibartz, Christopher
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p. 1801 - 1814
(2007/10/02)
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- The Stereoselective Retardation of the Alkaline Hydrolysis of Organic Esters by Binuclear Cu(II) Complexes with Cyclodextrins
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The alkaline hydrolysis of p-nitrophenyl acetate (p-NPA) in 1.0 mol dm-3 NaOH at 25 deg C was almost completely retarded by the addition of a binuclear Cu(II) complex with α-cyclodextrin Cu2α-CD).The dissociation constant for an inclusion complex of Cu2α-CD with p-NPA was determined to be 0.059 mmol dm-3, which is about one 200th that for an inclusion complex of α-CD with p-NPA.The alkaline hydrolysis of o- and m-nitrophenyl acetates was also retarded by Cu2α-CD, though the extent of retardation was much less than that for p-NPA.A binuclear Cu(II) complex with β-cyclodextrin (Cu2β-CD) also caused a stereoselective deceleration of the alkaline hydrolysis of the esters.However, the stereoselectivity of Cu2β-CD was not so remarkable as that of Cu2α-CD.Dissociation constants for inclusion complexes of Cu2α-CD with several alcohols and other organic substrates were determined by the kinetic examination of the competitive inhibition effect of the substrates on the association of Cu2α-CD with p-NPA.Cu2α-CD formed stable inclusion complexes with such disk-like molecules as cyclohexanol, cycloheptanol, and p-nitrobenzyl alcohol.The geometry of a Cu2α-CD-p-NPA inclusion complex was presumed on the basis of these results.
- Matsui, Yoshihisa,Suemitsu, Daisuke
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p. 1658 - 1662
(2007/10/02)
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