- SN2 mechanism for alcoholysis, aminolysis, and hydrolysis of acetyl chloride
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First-order solvolysis rate constants are reported for solvolyses of acetyl chloride in methanol and MeOD, and in binary aqueous mixtures with acetone, acetonitrile, ethanol, methanol, and trifluoroethanol at 0°C. Product selectivities (S = [MeCOOR]/[MeCOOH] x [water]/[alcohol]) are reported for solvolyses in ethanol/ and methanol/water at 0°C. Solvolyses of acetyl chloride show a high sensitivity to changes in solvent ionizing power, consistent with C-Cl bond cleavage. As the solvent is varied from pure ethanol (or methanol) to water, S values and rate-rate profiles show no evidence for the change in reaction channel observed for solvolyses of benzoyl and trimethylacetyl chlorides. However, using rate ratios in 40% ethanol/water and 97% trifluoroethanol/ water (solvents of similar ionizing power but different nucleophilicities) to compare sensitivities to nucleophilic attack, solvolyses of acetyl chloride are over 20-fold more sensitive to nucleophilic attack than benzoyl chloride. The solvent isotope effect of 1.29 (MeOH/MeOD) for acetyl chloride is similar to that for p-methoxybenzoyl chloride (1.22) and is lower than for benzoyl chloride (1.55). Second-order rate constants for aminolyses of acetyl chloride with m-nitroaniline in methanol at 0°C show that acetyl chloride behaves similarly to p-methoxybenzoyl chloride, whereas benzoyl chloride is 40-fold more sensitive to the added amine. The results indicate mechanistic differences between solvolyses of acetyl and benzoyl chlorides, and an SN2 mechanism is proposed for solvolyses and aminolyses by m-nitroaniline of acetyl chloride (i.e. these reactions are probably not carbonyl additions, but a strong sensitivity to nucleophilic attack accounts for their high rates).
- Bentley, T. William,Llewellyn, Gareth,McAlister, J. Anthony
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Read Online
- An Environmentally Benign, Catalyst-Free N?C Bond Cleavage/Formation of Primary, Secondary, and Tertiary Unactivated Amides
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Herein, we report an operationally simple, cheap, and catalyst-free method for the transamidation of a diverse range of unactivated amides furnishing the desired products in excellent yields. This protocol is environmentally friendly and operates under extremely mild conditions without using any promoter or additives. Significantly, this strategy has been implied in the chemoselective synthesis of a pharmaceutical molecule, paracetamol, on a gram-scale with excellent yield. We anticipate that this universally applicable strategy will be of great interest in drug discovery, biochemistry, and organic synthesis.
- Kumar, Vishal,Dhawan, Sanjeev,Girase, Pankaj Sanjay,Singh, Parvesh,Karpoormath, Rajshekhar
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p. 5627 - 5639
(2021/11/11)
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- 2-Arylamino-6-ethynylpurines are cysteine-targeting irreversible inhibitors of Nek2 kinase
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Renewed interest in covalent inhibitors of enzymes implicated in disease states has afforded several agents targeted at protein kinases of relevance to cancers. We now report the design, synthesis and biological evaluation of 6-ethynylpurines that act as covalent inhibitors of Nek2 by capturing a cysteine residue (Cys22) close to the catalytic domain of this protein kinase. Examination of the crystal structure of the non-covalent inhibitor 3-((6-cyclohexylmethoxy-7H-purin-2-yl)amino)benzamide in complex with Nek2 indicated that replacing the alkoxy with an ethynyl group places the terminus of the alkyne close to Cys22 and in a position compatible with the stereoelectronic requirements of a Michael addition. A series of 6-ethynylpurines was prepared and a structure activity relationship (SAR) established for inhibition of Nek2. 6-Ethynyl-N-phenyl-7H-purin-2-amine [IC50 0.15 μM (Nek2)] and 4-((6-ethynyl-7H-purin-2-yl)amino)benzenesulfonamide (IC50 0.14 μM) were selected for determination of the mode of inhibition of Nek2, which was shown to be time-dependent, not reversed by addition of ATP and negated by site directed mutagenesis of Cys22 to alanine. Replacement of the ethynyl group by ethyl or cyano abrogated activity. Variation of substituents on the N-phenyl moiety for 6-ethynylpurines gave further SAR data for Nek2 inhibition. The data showed little correlation of activity with the nature of the substituent, indicating that after sufficient initial competitive binding to Nek2 subsequent covalent modification of Cys22 occurs in all cases. A typical activity profile was that for 2-(3-((6-ethynyl-9H-purin-2-yl)amino)phenyl)acetamide [IC50 0.06 μM (Nek2); GI50 (SKBR3) 2.2 μM] which exhibited >5-10-fold selectivity for Nek2 over other kinases; it also showed > 50% growth inhibition at 10 μM concentration against selected breast and leukaemia cell lines. X-ray crystallographic analysis confirmed that binding of the compound to the Nek2 ATP-binding site resulted in covalent modification of Cys22. Further studies confirmed that 2-(3-((6-ethynyl-9H-purin-2-yl)amino)phenyl)acetamide has the attributes of a drug-like compound with good aqueous solubility, no inhibition of hERG at 25 μM and a good stability profile in human liver microsomes. It is concluded that 6-ethynylpurines are promising agents for cancer treatment by virtue of their selective inhibition of Nek2. This journal is
- Bayliss, Richard,Boxall, Kathy,Carbain, Benoit,Coxon, Christopher R.,Fry, Andrew M.,Golding, Bernard T.,Griffin, Roger J.,Hardcastle, Ian R.,Harnor, Suzannah J.,Mas-Droux, Corine,Matheson, Christopher J.,Newell, David R.,Richards, Mark W.,Sivaprakasam, Mangaleswaran,Turner, David,Cano, Céline
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supporting information
p. 707 - 731
(2020/08/24)
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- Iodine and Br?nsted acid catalyzed C–C bond cleavage of 1,3-diketones for the acylation of amines
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A metal-free N-acylation method of anilines with 1,3-diketones has been developed, by using iodine and p-toluene sulfonic acid as the co-catalysts. The reaction can proceed in 1,4-dioxane at elevated temperature to produce the corresponding amides with 48–89% yields. Further, the gram-scale experiment was carried out under the standard conditions and the possible mechanism was proposed.
- Zhou, Xiao-Yu,Chen, Xia,Yang, Dan
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supporting information
p. 177 - 184
(2019/11/26)
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- Probing 2H-Indazoles as Templates for SGK1, Tie2, and SRC Kinase Inhibitors
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The broader and systematic application of a novel scaffold is often hampered by the unavailability of a short and reliable synthetic access. We investigated a new strategy for the design and synthesis of an array of N2-substituted aza-2H-indazole derivatives as potential kinase inhibitors. Guided by a rational ligand alignment approach to qualify the so-far underrepresented aza-2H-indazole scaffold, indazoles were connected at the N2 position with a phenyl spacer and an arylsulfonamide or amide linkage. Initial profiling against a panel of 30 kinases confirmed the in silico predicted selectivity bias. A synthesized focused library of 52 different aza-2H-indazole derivatives showed good initial selective inhibition against SGK1, Tie2, and SRC kinases, with the best representatives having IC50 values in the range of 500 nm. In a comparative computational study, these data were analyzed and rationalized in light of docking studies.
- Schoene, Jens,Gazzi, Thais,Lindemann, Peter,Christmann, Mathias,Volkamer, Andrea,Nazaré, Marc
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p. 1514 - 1527
(2019/08/07)
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- Synthesis of acetamides from aryl amines and acetonitrile by diazotization under metal-free conditions
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An efficient and metal-free coupling reaction has been developed that affords acetamides from the corresponding aryl amines and acetonitrile. This method tolerates a wide range of functional groups and is selective toward aryl amines. Preliminary mechanistic studies were conducted.
- Duan, Pan,Guo, Yu,Kang, Huan,Li, Yi-Na,Wen, Xianghao,Xiao, Fang,Zeng, Yao-Fu,Zhang, Na-Na
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supporting information
p. 2169 - 2172
(2019/11/25)
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- SO2F2-Activated Efficient Beckmann Rearrangement of Ketoximes for Accessing Amides and Lactams
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A novel, mild and practical protocol for the efficient activation of the Beckmann rearrangement utilizing the readily available and economical sulfuryl fluoride (SO2F2 gas) has been developed. The substrate scope of the operationally simple methodology has been demonstrated by 37 examples with good to nearly quantitative isolated yields (over 90 % yield in most cases) in a short time, including B(OH)2, COOH, NH2, and OH substituted substrates. A tentative mechanism was proposed involving formation and elimination of key intermediate, sulfonyl ester.
- Zhang, Guofu,Zhao, Yiyong,Xuan, Lidi,Ding, Chengrong
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supporting information
p. 4911 - 4915
(2019/07/31)
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- Biogenic CuFe2O4 magnetic nanoparticles as a green, reusable and excellent nanocatalyst for acetylation reactions under solvent-free conditions
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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
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p. 15200 - 15206
(2018/09/29)
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- Potent and Selective Inhibitors of 8-Oxoguanine DNA Glycosylase
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The activity of DNA repair enzyme 8-oxoguanine DNA glycosylase (OGG1), which excises oxidized base 8-oxoguanine (8-OG) from DNA, is closely linked to mutagenesis, genotoxicity, cancer, and inflammation. To test the roles of OGG1-mediated repair in these pathways, we have undertaken the development of noncovalent small-molecule inhibitors of the enzyme. Screening of a PubChem-annotated library using a recently developed fluorogenic 8-OG excision assay resulted in multiple validated hit structures, including selected lead hit tetrahydroquinoline 1 (IC50 = 1.7 μM). Optimization of the tetrahydroquinoline scaffold over five regions of the structure ultimately yielded amidobiphenyl compound 41 (SU0268; IC50 = 0.059 μM). SU0268 was confirmed by surface plasmon resonance studies to bind the enzyme both in the absence and in the presence of DNA. The compound SU0268 was shown to be selective for inhibiting OGG1 over multiple repair enzymes, including other base excision repair enzymes, and displayed no toxicity in two human cell lines at 10 μM. Finally, experiments confirm the ability of SU0268 to inhibit OGG1 in HeLa cells, resulting in an increase in accumulation of 8-OG in DNA. The results suggest the compound SU0268 as a potentially useful tool in studies of the role of OGG1 in multiple disease-related pathways.
- Tahara, Yu-Ki,Auld, Douglas,Ji, Debin,Beharry, Andrew A.,Kietrys, Anna M.,Wilson, David L.,Jimenez, Marta,King, Daniel,Nguyen, Zachary,Kool, Eric T.
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supporting information
p. 2105 - 2114
(2018/02/19)
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- Selective cleavage of the N-propargyl group from sulfonamides and amides under ruthenium catalysis
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The selective cleavage of the N-propargyl group from sulfonamides and amides under ruthenium catalysis is described. The reaction tolerates a broad range of functional groups, and the desired products were obtained in 10–95% yield.
- Wang, Jingjing,Li, Feng,Pei, Wenlong,Yang, Mixue,Wu, Yidan,Ma, Danyang,Zhang, Furong,Wang, Jianhui
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supporting information
p. 1902 - 1905
(2018/04/19)
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- Copper-(II) Catalyzed N-Formylation and N-Acylation of Aromatic, Aliphatic, and Heterocyclic Amines and a Preventive Study in the C-N Cross Coupling of Amines with Aryl Halides
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A Cu-(II) catalyzed N-formylation and N-acylation of amines with moderate to excellent yields, using N, N-dimethyl formamide (DMF) and N, N-dimethyl acetamide (DMA) as a formyl and acylating sources in the presence of 1,2,4-triazole is reported. This novel, highly efficient and simple protocol shows broad substrate scope for aliphatic, aromatic, and heterocyclic amines. In addition, the conditions to prevent N-formylation and N-acylation impurities in the C?N cross coupling of amines and aryl halides are described typically when DMF and DMA are used as solvents, with various catalysts, ligands, and bases.
- Sonawane, Rahul B.,Rasal, Nishant K.,Bhange, Dattatraya S.,Jagtap, Sangeeta V.
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p. 3907 - 3913
(2018/09/12)
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- Eco-friendly, catalyst and solvent-free, synthesis of acetanilides and N-benzothiazole-2-yl-acetamides
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An expeditious and green synthesis of acetamides in a solvent-free simple way is described, without catalyst or additives, and in good yield by an instantaneous reaction of anilines or 2-aminothiazoles and acetic anhydride without external heating, and with simple purification. Sixteen substituted acetanilides and four N-benzothiazole-2-yl-acetamides were formed, but aliphatic amines of low molecular weight were not as effective as aromatic ones, and only cyclohexylamine and the enaminone ethyl 3-amino-2-butenoate afforded the corresponding acetamides in good yield.
- Cunha, Silvio,De Santana, Louren?o L. B.
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p. 1137 - 1144
(2017/05/01)
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- Efficient Heterogeneous Gold(I)-Catalyzed Direct C(sp2)–C(sp) Bond Functionalization of Arylalkynes through a Nitrogenation Process to Amides
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The first heterogeneous gold(I)-catalyzed direct C(sp2)–C(sp) bond functionalization of arylalkynes through a nitrogenation process to amides has been achieved by using an ordered mesoporous silica (MCM-41)-immobilized phosphine gold(I) complex [MCM-41-PPh3-AuCl] as catalyst and silver carbonate (Ag2CO3) as cocatalyst with trimethylsilyl azide (TMSN3) as a nitrogen source, yielding a variety of amides in moderate to excellent yields under mild conditions. This heterogeneous phosphine gold(I) complex shows the same turnover numbers as the homogeneous chloro(triphenylphosphine)gold(I) (Ph3PAuCl) and can easily be recovered by simple filtration of the reaction solution and recycled at least eight times without significant loss of activity, providing a novel, efficient, practical and economic method for the synthesis of amides from alkynes. (Figure presented.).
- Nie, Quan,Yi, Feiyan,Huang, Bin,Cai, Mingzhong
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p. 3968 - 3976
(2017/11/20)
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- Metal-Free Oxidative C=C Bond Cleavage of Electron-Deficient Enamines Promoted by tert -Butyl Hydroperoxide
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A novel tert -butyl hydroperoxide (TBHP)-promoted oxidative C=C double-bond cleavage of enamines is described. Heating a solution of an electron-deficient enamine in chlorobenzene at 80 °C in the presence of TBHP for two hours led to cleavage of the C=C bond. This study offers a new strategy to carry out C=O double-bond formation by the use of TBHP.
- Adib, Mehdi,Pashazadeh, Rahim,Gohari, Seyed Jamal Adin,Shahsavari, Fatemeh
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supporting information
p. 1481 - 1485
(2017/08/15)
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- Nickel-(II)-Catalyzed N-Formylation and N-Acylation of Amines
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A highly efficient protocol of Ni(II) metal complex, [Ni(quin)2], catalyzing N-formylation and N-acylation of amines with moderate to excellent yields, using N,N-dimethylformamide and N,N-dimethylacetamide in the presence of imidazole, is described here. The protocol shows broad substrate scope for aliphatic, aromatic, and heterocyclic amines.
- Sonawane, Rahul B.,Rasal, Nishant K.,Jagtap, Sangeeta V.
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supporting information
p. 2078 - 2081
(2017/04/28)
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- Doping of copper (I) oxide onto a solid support as a recyclable catalyst for acetylation of amines/alcohols/phenols and synthesis of trisubstituted imidazole
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A study of copper-mediated C-heteroatom especially C-N and C-O bond formations using simpler methodologies has been carried out. In the present work, acetylation of various substrates such as amines, phenols and alcohols; synthesis of 2,4,5-trisubstituted imidazole is done using simple and easily available starting materials. Copper (I) oxide was synthesized in situ by the reduction of Fehling's solution with glucose followed by its anchoring onto different supports like silica, HAP, basic alumina and cellulose. Comparison and contrasts between the reactivity of copper (I) oxide supported onto different supports for these reactions are made. The reactivity of copper (I) oxide seems to be largely dependent on the nature of support and the most active catalyst for a particular reaction was further characterized by different spectroscopic techniques such as FTIR, XRD, TGA, XPS, SEM, TEM and AAS. The catalysts were found to be stable, easily recyclable without any significant loss in activity. Graphical abstract: Applications of solid supported copper (I) oxides (where solid support is silica, HAP, cellulose and basic alumina) are studied for various organic transformations with special emphasis on C-N and C-O bond formation reactions.[Figure not available: see fulltext.]
- Gupta, Manjulla,Gupta, Monika
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p. 231 - 241
(2016/01/09)
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- Photo-Fries rearrangement of aryl acetamides: Regioselectivity induced by the aqueous micellar green environment
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Photochemical reactions tend to give more than one photoproduct. However, such a reaction can be a powerful synthetic tool when it is possible to conduct it in regioselective conditions yielding a single photoproduct. Water-surfactant solutions as reaction media can be considered as an approach in this context because they show products with different features than those from isotropic solutions. Here we describe results obtained from studying the effect on the prototypical photoreaction, known as the photo-Fries reaction of several substituted acetanilides and α-naphthyl acetamide within surfactant micelles (ionic and non-ionic micelles). This reaction involves homolytic cleavage of a C-N bond to yield a singlet radical pair. The surfactant micelles control the rotational and translational mobility of the radical pair, resulting in noticeable photoproduct selectivity.
- Iguchi, Daniela,Erra-Balsells, Rosa,Bonesi, Sergio M.
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p. 105 - 116
(2016/01/20)
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- Selective N-acetylation of aromatic amines using acetonitrile as acylating agent
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A method for N-acetylation of amines has been developed using acetonitrile as an acylating agent and in situ generated trimethylsilyl iodide as the catalyst under microwave heating condition. The reaction is selective toward aromatic amines while aliphatic amines remain intact. The process eliminates the requirement of toxic acylating reagents like acetic anhydride and acetyl chloride.
- Saikia, Ujwal Pratim,Hussain, Farhaz L.,Suri, Mrinaly,Pahari, Pallab
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supporting information
p. 1158 - 1160
(2016/03/09)
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- Efficient conversion of acids and esters to amides and transamidation of primary amides using OSU-6
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OSU-6, an MCM-41 type hexagonal mesoporous silica with strong Bronsted acid properties, has been used to promote the high-yield conversion of carboxylic acids and esters to carboxamides as well as transamidations of primary amides in a one-pot solventless approach. A metal-free heterogeneous catalyst that promotes all of these processes has not been previously reported. OSU-6 enables these transformations to proceed in shorter times and at lower temperatures for a broad range of substrates. An added benefit is that the catalyst can be recycled and reused multiple times without significant loss of activity.
- Nammalwar, Baskar,Muddala, Nagendra Prasad,Watts, Field M.,Bunce, Richard A.
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p. 9101 - 9111
(2015/11/09)
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- Beckmann rearrangement of oximes using doped silica gel complex
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A new complex of perchloric acid absorbed on silica gel (doped silica gel) and dichloromethane was found to be very effective for converting ketoximes into their corresponding amides or lactams with excellent conversion via the Beckmann rearrangement. This method offers significant advantages such as efficiency and mild reaction conditions with shorter reaction time.
- Umanadh,Reddy, N. Srinivasa,Mukkanti, Khagga,Omprakash
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p. 1209 - 1211
(2015/02/19)
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- ZnAl2O4@SiO2 nanocomposite catalyst for the acetylation of alcohols, phenols and amines with acetic anhydride under solvent-free conditions
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A ZnAl2O4@SiO2 nanocomposite was prepared from metal nitrates and tetraethyl orthosilicate by the sol-gel process, and characterized by X-ray diffraction, Fourier transform infrared, transmission electron microscopy, and N2 adsorption-desorption measurements. The nanocomposite was tested as a heterogeneous catalyst for the acetylation of alcohols, phenols, and amines under solvent-free conditions. Under optimized conditions, efficient acetylation of these substrates with acetic anhydride over the ZnAl2O4@SiO2 nanocomposite was obtained. Acetylation of anilines and primary aliphatic amines proceeded rapidly at room temperature, while the reaction time was longer for the acetylation of alcohols and phenols, showing that an amine NH2 group can be selectively acetylated in the presence of alcoholic or phenolic OH groups. The catalyst can be reused without obvious loss of catalytic activity. The catalytic activity of the ZnAl2O4@SiO2 nanocomposite was higher than that of pure ZnAl2O4. The method gives high yields, and is clean, cost effective, compatible with substrates having other functional groups and it is suitable for practical organic synthesis.
- Farhadi, Saeed,Jahanara, Kosar
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p. 368 - 375
(2014/04/03)
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- Sol-gel derived LaFeO3/SiO2 nanocomposite: Synthesis, characterization and its application as a new, green and recoverable heterogeneous catalyst for the efficient acetylation of amines, alcohols and phenols
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LaFeO3/SiO2 nanocomposite was synthesized by the sol-gel process from metal nitrates and tetraethyl orthosilicate (TEOS) as the SiO2 source. The nanocomposite product was characterized by XRD, FT-IR, SEM, and surface area measurements and was used as a heterogeneous catalyst for the efficient acetylation of amines, alcohols and phenols to the corresponding acetates using acetic anhydride under solvent-free conditions. Among the various substrates, acetylation of amines was preceded rapidly, so that an amine group could be selectively acetylated in the presence of alcoholic or phenolic hydroxyl groups by the appropriate choice of reaction time. The catalyst can also be reused several times without the loss of activity. In addition, the catalytic activity of the LaFeO3/SiO2 nanocomposite was higher than that of the pure LaFeO3 nanoparticles. The method is high yielding, clean, cost effective, compatible with the substrates having other functional groups and very suitable for the practical organic synthesis.
- Farhadi, Saeed,Jahanara, Kosar,Sepahdar, Asma
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p. 1103 - 1112
(2014/08/05)
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- Novel trisubstituted acridines as human telomeric quadruplex binding ligands
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A novel series of trisubstituted acridines were synthesized with the aim of mimicking the effects of BRACO19. These compounds were synthesized by modifying the molecular structure of BRACO19 at positions 3 and 6 with heteroacyclic moieties. All of the derivatives presented in the study exhibited stabilizing effects on the human telomeric DNA quadruplex. UV-vis spectroscopy, circular dichroism, linear dichroism and viscosimetry were used in order to study the nature of the DNA binding in more detail. The results show that all of the novel derivatives were able to fold the single-stranded DNA sequences into antiparallel G-quadruplex structures, with derivative 15 exhibiting the highest stabilizing capability. Cell cycle analysis revealed that a primary trend of the "braco"-like derivatives was to arrest the cells in the S- and G 2M-phases of the cell cycle within the first 72 h, with derivative 13 and BRACO19 proving particularly effective in suppressing cell proliferation. All studies derivatives were less toxic to human fibroblast cell line in comparison with HT 29 cancer cell line.
- Ungvarsky, Jan,Plsikova, Jana,Janovec, Ladislav,Koval, Jan,Mikes, Jaromir,Mikesová, Lucia,Harvanova, Denisa,Fedorocko, Peter,Kristian, Pavol,Kasparkova, Jana,Brabec, Viktor,Vojtickova, Maria,Sabolova, Danica,Stramova, Zuzana,Rosocha, Jan,Imrich, Jan,Kozurkova, Maria
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- ANTI-VIRAL COMPOUNDS
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Described herein are compounds and related compositions for the treatment of viral infections, including RNA viral infection, and compounds that can modulate the RIG-I pathway in vertebrate cells,including compounds that can activate the RIG-I pathway.
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Paragraph 00316; 00317
(2018/09/18)
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- The beckmann rearrangement executed by visible-light-driven generation of vilsmeier-haack reagent
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A new and efficient approach for the Beckmann rearrangement is reported. The protocol involves eosin? Y catalyzed, visible-light-mediated in situ formation of the Vilsmeier-Haack reagent from CBr4 and a catalytic amount of DMF for activation of ketoximes at room temperature. The method is operationally simple and avoids the need for any corrosive, water-sensitive reagents and elevated temperatures. Georg Thieme Verlag Stuttgart New York.
- Srivastava, Vishnu P.,Yadav, Arvind K.,Yadav, Lal Dhar S.
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supporting information
p. 665 - 670
(2014/04/03)
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- A new ferrocene-based bulky pyridine as an efficient reusable homogeneous catalyst
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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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- Recyclable, highly efficient and low cost nano-MgO for amide synthesis under SFRC: A convenient and greener 'NOSE' approach
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A clean synthesis of amide derivatives has successfully been accomplished utilizing reusable nano-MgO under 'SFRC' (solvent free reaction condition). The 'green-ness' of this protocol makes it a benign alternative for the large scale synthesis.
- Das, Vijay Kumar,Devi, Rashmi Rekha,Thakur, Ashim Jyoti
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p. 118 - 125
(2013/06/26)
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- Nanoceria-catalyzed highly efficient procedure for N-formylation of amines at room temperature under solvent-free conditions
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Nanoceria-catalyzed simple and efficient protocol for the N-formylation of amines using formic acid at room temperature under solvent-free conditions shows high yield of desired product chemoselectivity and improvement in reaction time.
- Patil, Umakant B.,Singh, Abhilash S.,Nagarkar, Jayashree M.
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supporting information
p. 524 - 526
(2013/06/05)
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- Green and efficient method for the acylation of amines and phenols in the presence of hydrotalcite in water
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In this study a mild, efficient and environmentally friendly method has been developed for the synthesis of amides and esters in the presence of hydrotalcite in water at room temperature. Different types of amines and phenols have been used and in all cases the products were obtained in moderate to high yields after an easy work-up. This method follows the principles of green chemistry.
- Massah, Ahmad Reza,Toghyani, Mitra,Najafabadi, Batool Hojati
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p. 603 - 605,3
(2020/09/16)
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- Synthesis and evaluation of a photochromic surfactant for organic reactions in aqueous media
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A novel photochromic azobenzene-based surfactant was described for organic chemistry in water. The molecule 4-butylazobenzyl-4′-triazologlucuronic acid sodium salt thus synthesized can be isomerized from its trans to its cis form reversibly in solution by simple light irradiation. That property allowed the recyclability of a model acetylation reaction performed in the surfactant media, compared to the well-known, commercially available sodium dodecyl sulfate surfactant media.
- Drillaud, Nicolas,Banaszak-Léonard, Estelle,Pezron, Isabelle,Len, Christophe
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p. 9553 - 9561
(2013/01/15)
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- A facile and efficient method for the selective deacylation of N-arylacetamides and 2-chloro-Narylacetamides catalyzed by SOCl2
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Thionyl chloride efficiently and selectively promoted the deacylation of N-arylacetamides and 2-chloro-N-arylacetamides, under anhydrous conditions, without effecting the ester group, aminosulfonyl group, or benzyloxyamide group. This method, which has been successfully applied to a variety of substrates including different N-arylacetamides and 2-chloro-N-arylacetamides, has the attractive advantages of inexpensive reagents, satisfactory selectivity, excellent yields, short reaction time, and convenient workup. This new method can probably be used to selectively deacylate between aromatic amides and alkyl amides. Springer Science+Business Media B.V. 2011.
- Wang, Gong-Bao,Wang, Lin-Fa,Li, Chao-Zhang,Sun, Jing,Zhou, Guang-Ming,Yang, Da-Cheng
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experimental part
p. 77 - 89
(2012/05/20)
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- Nano rod-shaped and reusable basic Al2O3 catalyst for N-formylation of amines under solvent-free conditions: A novel, practical and convenient 'NOSE' approach
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An expeditious, simple, highly efficient, practical and green protocol for the N-formylation of alkyl/aryl amines and indole derivatives catalyzed by novel nano rod-shaped basic Al2O3 under solvent-free conditions has been developed. The catalyst is efficiently recycled up to the 5th run, an important point in the domain of green chemistry. The methodology provides cleaner conversion, shorter reaction times and high selectivity which makes the protocol attractive. The Royal Society of Chemistry 2012.
- Das, Vijay Kumar,Devi, Rashmi Rekha,Raul, Prasanta Kumar,Thakur, Ashim Jyoti
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supporting information; experimental part
p. 847 - 854
(2012/04/23)
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- Efficient amide formation from arylamines and esters promoted by AlCl 3/Et3N: An experimental and computational investigation
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Efficient and selective preparation of amides from arylamines and esters has been achieved with an AlCl3/Et3N pair under mild conditions. A large number of arylamines were successfully acylated to the corresponding amides in high yields and short reaction times. For instance, a 94% yield of p-bromoacetanilide was obtained from p-bromoaniline and ethyl acetate in 10 min at room temperature. In addition, a computational study on the N-acylation of amines was performed using density functional theory. It was found that the energy barrier for N-acylation of aniline is 10 kcal/mol higher than that of methylamine. In the presence of AlCl3, the activation energy for the N-acylation of aniline was reduced by 27.7 kcal/mol with the endothermic process becoming exothermic. Springer Science+Business Media B.V. 2012.
- Tong, Xinli,Ren, Zhangshun,Que, Xiaolong,Yang, Qiwu,Zhang, Wenqin
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p. 1961 - 1968
(2013/02/22)
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- Preparation of ionic liquid-based vilsmier reagent from novel multi-purpose dimethyl formamide-like ionic liquid and its application
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In continuation of research to explore the applied potential of DMF-like ionic liquid, the ionic liquid version of N,N-dimethyliminiumchloride (Vilsmier reagent) has been synthesized from DMF-like ionic liquid and tested effectively for its capacity to achieve more useful organic transformations. The results show that DMF-like ionic liquid is world's first task specific ionic liquid which has catalyzed numerous diverse type of reaction and is multipurpose in its application. Thus a new term for this DMF-like ionic liquid has been coined that is DMF-like "multipurpose" ionic liquid. Copyright
- Hullio, Ahmed Ali,Mastoi
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scheme or table
p. 1647 - 1657
(2012/09/21)
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- 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
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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
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experimental part
p. 2365 - 2372
(2011/10/31)
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- Thermally decomposed Ni-Fe-hydrotalcite: A highly active catalyst for the solvent-free N-acylation of different amines by acid chlorides
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A composite Ni-Fe catalyst obtained from the thermal decomposition of Ni-Fe-hydrotalcite at 600 °C shows very high activity in the solvent-free N-acylation of amines by different acid chlorides with high product yields under very mild reaction conditions (viz. room temperature, short reaction period and small amount of catalyst). The catalyst also shows excellent reusability in the reaction. The crystalline phases present in the catalyst are mixed oxides and hydroxides of nickel and iron. The high catalytic activity of the decomposed Ni-Fe-hydrotalcite is attributed to the formation of uniformly distributed Ni-Fe metal oxides and hydroxides.
- Choudhary,Dumbre
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experimental part
p. 1351 - 1356
(2012/01/06)
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- Citric acid catalysed Beckmann rearrangement, under solvent free conditions
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Citric acid is reported to be a highly efficient and eco-friendly catalyst for the Beckmann rearrangement under solvent free conditions.
- Thopate, Shankar Ramchandra,Kote, Santosh Rajaram,Rohokale, Sandeep Vasantrao,Thorat, Nitin Madhukar
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experimental part
p. 124 - 125
(2011/07/07)
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- Beckmann rearrangement of oximes using pivaloyl chloride/DMF complex
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A new complex of pivaloyl chloride and DMF was found to be very effective for converting ketoximes into their corresponding amides or lactams with excellent conversion via the Beckmann rearrangement. This method offers significant advantages such as efficiency and mild reaction conditions with shorter reaction time.
- Narahari, Srinivasa Reddy,Reguri, Buchi Reddy,Mukkanti
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experimental part
p. 4888 - 4891
(2011/10/05)
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- Microwave-assisted synthesis of nano-sized cadmium oxide as a new and highly efficient catalyst for solvent free acylation of amines and alcohols
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In present studies, a new and efficient method for synthesis of cadmium oxide nanoparticles by using microwave (MW) activation is reported. To ensure the specific efficiency of microwave irradiation versus conventional heating, the synthesis of Cd(OH)2 as precursor of CdO was carried out under similar temperature (80 °C), time and reaction conditions without microwave irradiation. The formation of CdO was characterized by XRD, TEM, FT-IR analysis. Catalytic activity of CdO nanopowder for acylation of alcohols, phenols and amines has been investigated. The results show that the reaction times and yields of desired products were improved by using CdO.
- Mazaheritehrani,Asghari,Orimi, R. Lotfi,Pahlavan
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experimental part
p. 2554 - 2564
(2010/10/21)
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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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- Synthesis, photophysical and NMR evaluations of thiourea-based anion receptors possessing an acetamide moiety
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The synthesis and photophysical evaluation of three diaryl thiourea-based anion receptors (4-6) for comparison with their urea counterparts (1-3) is outlined. These anion receptors posses an acetamide functionality on one of the aryl groups and an electron-withdrawing CF3 group on the other. By varying the position of the acetamide group, in the o-, m- and p-positions of 4-6, respectively, the anion binding ability was both tuneable and found to be, in some cases, significantly different from that seen for the urea analogues 1-3. The binding affinities of the receptors 4-6, as well as the binding stoichiometries, were evaluated using UV-vis absorption spectroscopy in MeCN. However, these receptors were not sufficiently emissive to quantify the anion recognition using fluorescence. The results confirmed strong binding of these receptors to anions such as fluoride, acetate, phosphate, pyrophosphate and chloride. Nevertheless, the overall results obtained did not conform to the anticipated trends seen for 1-3, which is most likely due to the enhanced binding affinity of the thiourea analogues 4-6. The binding interactions were also investigated by using 1H NMR which confirmed that these receptors interacted with the anions in a stepwise manner, where the primary anion binding interaction occurred at the thiourea side, which led to an activation of the acetamide moiety towards the second anion binding interaction, an example of an allosteric activation mode.
- Boyle, Elaine M.,McCabe, Thomas,Gunnlaugsson, Thorfinnur
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experimental part
p. 586 - 597
(2011/01/03)
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- Metal acetate/metal oxide in acetic acid: An efficient reagent for the chemoselective N-acetylation of amines under green conditions
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The use of catalytic amount of metal acetate or metal oxide in acetic acid is a new and highly efficient acetylating system for chemoselective N-acetylation of primary and secondary amines in excellent yields under reflux condition. No other solvent is required. The noted features of this method include mild reaction conditions, use of innocuous reagents, excellent yields, convenient work-up, and reuse of catalyst.
- Brahmachari, Goutam,Laskar, Sujay,Sarkar, Sajal
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experimental part
p. 288 - 295
(2010/10/18)
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- A green approach to chemoselective N-acetylation of amines using catalytic amount of zinc acetate in acetic acid under microwave irradiation
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It has been found for the first time that zinc acetate alone can act as a selective A'-acetylating agent without any solvent under closed vessel microwave irradiation. It is also observed that the use of a catalytic amount of this reagent in acetic acid is sufficient enough for smooth running of A'-acetylation of a number of structurally diverse amines, and the reaction is chemoselective with respect to phenols, thiols, acids and alcohols. Herein is reported a simple, efficient, cost-effective and environmentally benign alternative method for chemoselective A'-acetylation of amines using catalytic amount of zinc acetate in acetic acid under microwave irradiation. The reaction procedure requires no other solvent, and is rapid with good to excellent yields.
- Brahmachari,Laskar,Sarkar
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experimental part
p. 1274 - 1281
(2010/12/24)
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- A simple and highly efficient one-pot procedure for the synthesis of amides via beckmann rearrangements using 1-tosylimidazole (TsIm)
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A facile and highly efficient method for one-pot Beckmann rearrangement of ketoximes into N-substituted amides using N-(p-toluenesulfonyl)imidazole (TsIm) is described. In this method, ketoximes are refluxed with TsIm and Cs2CO3 in the presence of SiO2 as a recyclable catalyst in DMF affording the corresponding amides in high yields. This methodology is highly efficient and regioselective for various structurally diverse ketoximes including symmetrical and unsymmetrical as well as cyclic oximes. The results of quantum mechanical studies used to rationalize the experimental outcomes are discussed. Copyright Taylor & Francis Group, LLC.
- Rad, Mohammad Navid Soltani,Khalafi-Nezhad, Ali,Behrouz, Somayeh,Amini, Zohreh,Behrouz, Marzieh
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experimental part
p. 1658 - 1671
(2010/09/09)
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- Efficient procedure for beckmann rearrangement of ketoximes catalyzed by sulfamic acid/Zinc chloride
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The Beckmann rearrangement of a variety of ketoximes to corresponding amides catalyzed by sulfamic acid and zinc chloride was carried out in good yields at refluxing temperature in acetonitrile. Copyright Taylor & Francis Group, LLC.
- Li, Ji-Tai,Meng, Xian-Tao,Yin, Ying
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experimental part
p. 1445 - 1452
(2010/07/08)
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- Simple and efficient method for acetylation of alcohols, phenols, amines, and thiols using anhydrous NiCl2 under solvent-free conditions
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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.
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experimental part
p. 4384 - 4395
(2010/04/29)
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- Mild and useful method for n-acylation of amines
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Iodine is found to promote quantitative N-acylation of primary and secondary amines (aliphatic and aromatic) in a very short time with an equimolar amount of acetyl chloride and benzoyl chloride under solvent-free conditions at room temperature. This catalytic acylation of amines offers an additional useful method for the acetylation using acetyl chloride instead of acetic anhydride and other acetylating agents. This method is also useful in the N-acylation of heterocycles. Mild reaction condition, high selectivity, efficiency, and good yields are some of the major advantages of the procedure.
- Phukan, Kandarpa,Ganguly, Mausumi,Devi, Nirada
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experimental part
p. 2694 - 2701
(2009/12/06)
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- Silica supported zinc chloride catalyzed acetylation of amines, alcohols and phenols
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Silica supported zinc chloride (SiO2-ZnCl2) has been prepared and found to efficiently catalyze the acetylation of amines, alcohols and phenols by stirring in acetonitrile at 80°C under heterogeneous conditions. The catalyst can be separated from the reaction medium simply by filtration and re-used up to four times.
- Gupta, Raman,Kumar, Vineet,Gupta, Monika,Paul, Satya,Gupta, Rajive
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experimental part
p. 1739 - 1743
(2009/06/28)
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- The recognition and sensing of anions through "positive allosteric effects" using simple urea-amide receptors
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(Chemical Equation Presented) The design, synthesis, and X-ray crystallographic analysis of three simple diaryl-urea based anion receptors possessing an amide moiety on one of the aryl groups, and an electron withdrawing CF3 group on the other, is described. The three receptors differ only in the position of the amide functionality relative to the hydrogen bonding urea moiety (being para, meta, and ortho for 1, 2, and 3, respectively). This simple modification was shown to have a significant effect on the anion recognition ability, the strength of the recognition process, and the stoichiometry (host/guest) for these sensors. We demonstrate, by using both UV-vis absorption and 1H NMR spectroscopy, that these factors are caused by the ability of the amide moiety to both modulate the anion binding selectivity and the sensitivity of the urea moiety. We also demonstrate that, in the case of 1 and 2, this anion recognition at the urea moiety leads to concomitant activation (through enhanced inductive effect) in the amide functionality toward anions, which leads to the formation of an overall 1:2 (sensor/anion) binding stoichiometry for these receptors. This "activation" we describe as being an example of a "positive allosteric activation" by the urea site, caused directly by the first anion binding interaction, which to the best of our knowledge, has not been previously demonstrated for anion recognition and sensing.
- Dos Santos, Cidalia M. G.,McCabe, Thomas,Watson, Graeme W.,Kruger, Paul E.,Gunnlaugsson, Thorfinnur
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supporting information; experimental part
p. 9235 - 9244
(2009/04/06)
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- New, efficient, selective, and one-pot method for acylation of amines
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Hydrazine hydrate with acetic and propionic acids was an efficient reagent for acylation of primary and secondary amines at reflux temperatures. The reported one-pot method is high-yielding, simple, mild, and inexpensive. Copyright Taylor & Francis Group, LLC.
- Basanagouda, Mahantesha,Kulkarni, Manohar V.,Kalkhambkar, Raj G.,Kulkarni, Geeta M.
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p. 2929 - 2940
(2008/12/22)
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