- Decarboxylative Ritter-Type Amination by Cooperative Iodine (I/III)─Boron Lewis Acid Catalysis
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Recent years have witnessed important progress in synthetic strategies exploiting the reactivity of carbocations via photochemical or electrochemical methods. Yet, most of the developed methods are limited in their scope to certain stabilized positions in molecules. Herein, we report a metal-free system based on the iodine (I/III) catalytic manifold, which gives access to carbenium ion intermediates also on electronically disfavored benzylic positions. The unusually high reactivity of the system stems from a complexation of iodine (III) intermediates with BF3. The synthetic utility of our decarboxylative Ritter-type amination protocol has been demonstrated by the functionalization of benzylic as well as aliphatic carboxylic acids, including late-stage modification of different pharmaceutical molecules. Notably, the amination of ketoprofen was performed on a gram scale. Detailed mechanistic investigations by kinetic analysis and control experiments suggest two mechanistic pathways.
- Narobe, Rok,Murugesan, Kathiravan,Schmid, Simon,K?nig, Burkhard
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p. 809 - 817
(2022/01/15)
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- Beckmann rearrangement of ketoximes promoted by cyanuric chloride and dimethyl sulfoxide under a mild condition
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Synthesis of amides via Beckmann rearrangement of ketoximes promoted by cyanuric chloride (TCT)/DMSO under mild conditions has been reported. Conditions of the Beckmann rearrangement, e.g., solvents, the ratios of TCT/DMSO, and the temperature, were investigated using diphenylmethanone oxime as a substrate. The optimized conditions were adopted to afford fourteen amides with yields ranging from 20% to 99%. A plausible mechanism involving an active dimethyl alkoxysulfonium intermediate was proposed according to the mass spectrometry analysis. To our best knowledge, this is the first case of study on Beckmann rearrangement of ketoximes promoted by TCT/DMSO under a mild condition to afford amides efficiently.
- Ma, Ruonan,Chen, Xueyuan,Xiao, Zhiyin,Natarajan, Mookan,Lu, Chunxin,Jiang, Xiujuan,Zhong, Wei,Liu, Xiaoming
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supporting information
(2021/01/06)
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- Method for synthesizing amide compound through photocatalysis in water phase
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The invention discloses a method for synthesizing an amide compound through photocatalysis in a water phase. The method comprises the following steps: putting catalysis amounts of a free radical initiator, an amine derivative, a carboxylic acid derivative, a phase transfer catalyst, an inorganic base and water into a reaction container, carrying out a reaction in a photocatalysis reaction instrument at certain power under a room temperature condition, after a certain time, carrying out extraction by using a small amount of ethyl acetate, and carrying out recrystallization, so as to obtain theamide compound, wherein the free radical initiator is eosin, methyl orange, sodium persulfate, ammonium persulfate or potassium peroxodisulfate, the phase transfer catalyst is tetrabutylammonium bromide, and the power of the photocatalytic reaction instrument is 5W. By adopting the method disclosed by the invention, toxic thionyl chloride or phosphorus oxychloride is not needed for a chlorinationreaction, water is adopted as a solvent, a novel photocatalysis method is used, and the amide compound with a high yield can be prepared through a room-temperature reaction for 2-5 hours with an incandescent light bulb of 5W, and in addition, the method is simple in aftertreatment, and low in cost and is an ideal green synthesis method of amide compounds.
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Paragraph 0093
(2019/10/01)
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- Formation of carbon–nitrogen bonds in carbon monoxide electrolysis
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The electroreduction of CO2 is a promising technology for carbon utilization. Although electrolysis of CO2 or CO2-derived CO can generate important industrial multicarbon feedstocks such as ethylene, ethanol, n-propanol and acetate, most efforts have been devoted to promoting C–C bond formation. Here, we demonstrate that C–N bonds can be formed through co-electrolysis of CO and NH3 with acetamide selectivity of nearly 40% at industrially relevant reaction rates. Full-solvent quantum mechanical calculations show that acetamide forms through nucleophilic addition of NH3 to a surface-bound ketene intermediate, a step that is in competition with OH– addition, which leads to acetate. The C–N formation mechanism was successfully extended to a series of amide products through amine nucleophilic attack on the ketene intermediate. This strategy enables us to form carbon–heteroatom bonds through the electroreduction of CO, expanding the scope of products available from CO2 reduction.
- Jouny, Matthew,Lv, Jing-Jing,Cheng, Tao,Ko, Byung Hee,Zhu, Jun-Jie,Goddard, William A.,Jiao, Feng
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p. 846 - 851
(2019/09/03)
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- Tris(pyrazolyl)borate Cobalt-Catalyzed Hydrogenation of C=O, C=C, and C=N Bonds: An Assistant Role of a Lewis Base
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The combination of tris(pyrazolyl)borate cobalt complexes and Lewis base is developed as an efficient catalyst precursor in the homogeneous hydrogenation. A broad substrate scope including carbonyls, alkenes, enamines, and imines is reduced with 60 atm of H2 at 60 °C. Mechanistic studies support the hydrogenation operates through a frustrated Lewis pair (FLP)-like reduction process. These results highlight the development of novel non-noble metal catalytic processes, when combined with the diverse small molecule activation chemistry associated with FLPs.
- Lin, Yang,Zhu, De-Ping,Du, Yi-Ran,Zhang, Rui,Zhang, Suo-Jiang,Xu, Bao-Hua
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supporting information
p. 2693 - 2698
(2019/04/25)
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- Sustainable hydrogenation of aliphatic acyclic primary amides to primary amines with recyclable heterogeneous ruthenium-tungsten catalysts
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The hydrogenation of amides is a straightforward method to produce (possibly bio-based) amines. However current amide hydrogenation catalysts have only been validated in a rather limited range of toxic solvents and the hydrogenation of aliphatic (acyclic) primary amides has rarely been investigated. Here, we report the use of a new and relatively cheap ruthenium-tungsten bimetallic catalyst in the green and benign solvent cyclopentyl methyl ether (CPME). Besides the effect of the Lewis acid promotor, NH3 partial pressure is identified as the key parameter leading to high primary amine yields. In our model reaction with hexanamide, yields of up to 83% hexylamine could be achieved. Beside the NH3 partial pressure, we investigated the effect of the catalyst support, PGM-Lewis acid ratio, H2 pressure, temperature, solvent tolerance and product stability. Finally, the catalyst was characterized and proven to be very stable and highly suitable for the hydrogenation of a broad range of amides.
- Coeck, Robin,Berden, Sarah,De Vos, Dirk E.
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supporting information
p. 5326 - 5335
(2019/10/11)
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- Ozone and ozone/vacuum-UV degradation of diethyl dithiocarbamate collector: Kinetics, mineralization, byproducts and pathways
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The diethyl dithiocarbamate (DDC) collector, a precursor of toxic N-nitrosamines, is detected in flotation wastewaters usually at the ppm level. In this study, the O3 and O3/Vacuum-UV (O3/VUV) processes were compared to investigate the efficient removal of DDC with a low risk of N-nitrosamine formation. The results showed that 99.55% of DDC was removed at 20 min by O3/VUV, and the degradation rate constant was 3.99 times higher than that using O3-alone. The C, S and N mineralization extents of DDC using O3/VUV reached 36.36%, 62.69% and 79.76% at 90 min, respectively. O3/VUV achieved a much higher mineralization extent of DDC than O3-alone. After 90 min of degradation, O3/VUV achieved lower residual concentrations of CS2 and H2S, and released lower amounts of gaseous sulfur byproducts compared to O3-alone. The solid phase extraction and gas chromatography-mass spectrometry (SPE/GC-MS) analysis indicated that the main byproducts in O3/VUV degradation of DDC were amide compounds without the detection of N-nitrosamines. The avoidance of N-nitrosamine formation might be attributed to exposure of UV irradiation and enhanced formation of OH radicals in the O3/VUV system. The degradation pathways of DDC were proposed. This work indicated that O3/VUV was an efficient alternative treatment technique for the removal of DDC flotation collector with low risk of N-nitrosamine formation.
- Fu, Pingfeng,Ma, Yanhong,Yang, Huifen,Li, Gen,Lin, Xiaofeng
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p. 23579 - 23588
(2019/08/12)
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- Direct Observation of Acyl Nitroso Compounds in Aqueous Solution and the Kinetics of Their Reactions with Amines, Thiols, and Hydroxamic Acids
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Acyl nitroso compounds or nitrosocarhonyls (RC(O)N=O) are reactive short-lived electrophiles, and their hydrolysis and reactions with nucleophiles produce HNO. Previously, direct detection of acyl nitroso species in nonaqueous media has been provided by time-resolved infrared spectroscopy demonstrating that its half-life is about 1 ms. In the present study hydroxamic acids (RC(O)NHOH) are oxidized electrochemically in buffered aqueous solutions (pH 5.9-10.2) yielding transient species characterized by their maximal absorption at 314-330 nm. These transient species decompose via a first-order reaction yielding mainly HNO and the respective carboxylic acid and therefore are ascribed to RC(O)N=O. The sufficiently long half-life of RC(O)N=O in aqueous solution allows for the first time the study of the kinetics of its reactions with various nucleophiles demonstrating that the nucleophilic reactivity follows the order thiolate > hydroxamate > amine. Metal chelates of CH3C(O)NHOH catalyze the hydrolysis of CH3C(O)N=O at the efficacy order of CuII > ZnII > NiII > CoII where only CuII catalyzes the hydrolysis also in the absence of the hydroxamate. Finally, oxidation of hydroxamic acids generates HNO, and the rate of this process is determined by the half-life of the respective acyl nitroso compound.
- Maimon, Eric,Lerner, Ana,Samuni, Amram,Goldstein, Sara
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p. 7006 - 7013
(2018/09/06)
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- Method for preparing methallyl alcohol and amide simultaneously
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A method for preparing methallyl alcohol and amide simultaneously is characterized in that methylallyl carboxylate taken as a raw material and an amine compound taken as an ammonolysis agent react under the action of a catalyst to produce methallyl alcohol and an amide compound. The methylallyl carboxylate and the amine compound taken as the ammonolysis agent are firstly adopted, and the methallyl alcohol and the amide compound are obtained under the action of the catalyst. The reaction process is a bulk reaction, no solvents are added, almost no wastewater or salt are produced, and byproduct methyl allyl ether is not produced; the defect that a large number of wastewater is produced through hydrolysis is overcome due to adoption of ammonolysis, the methallyl alcohol and the amide compound are coproduced directly by use of ammonoysis, coupling production is realized, and the cost is reduced.
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Paragraph 0040-0041
(2017/11/29)
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- One-pot conversion of cyclohexanol to ?-caprolactam using a multifunctional Na2WO4-acidic ionic liquid catalytic system
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Na2WO4-acidic ionic liquid was used as a simple, ecofriendly, recyclable and efficient catalytic system for the one-pot conversion of cyclohexanol to ?-caprolactam. The effect of the structure of the ionic liquid on the catalytic activity of this system was investigated, and the results revealed that sulfonic acid-functionalized ionic liquids with HSO4?as an anion gave the best results. The highly efficient performance of this catalyst system was attributed to the phase-transfer behavior of the cation of the ionic liquid, the improved coordination of the substrate to bisperoxotungstate during the oxidation reaction, and the stabilization of the intermediate formed during the Beckmann rearrangement.
- Wang, Hefang,Jia, Liyuan,Hu, Rongbin,Gao, Meidan,Wang, Yanji
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- Direct Preparation of Amides from Amine Hydrochloride Salts and Orthoesters: A Synthetic and Mechanistic Perspective
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The conversion of a wide range of primary and secondary aliphatic and a few arylamine hydrochloride salts to their corresponding acetamides with trimethyl orthoacetate is described. Mechanistic studies using NMR and gas chromatography-mass spectrometry techniques indicate these reactions proceed via an O-methylimidate intermediate that undergoes in situ demethylation by chloride, affording the corresponding acetamides. Synthetically, this reaction represents a practical, high-yielding protocol with a simple workup for the rapid conversion of amine hydrochloride salts to acetamides.
- Di Grandi, Martin J.,Bennett, Caitlin,Cagino, Kristen,Muccini, Arnold,Suraci, Corey,Saba, Shahrokh
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supporting information
p. 2601 - 2607
(2015/11/28)
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- Carboxyl activation of 2-mercapto-4,6-dimethylpyrimidine through n-acyl-4,6-dimethylpyrimidine-2-thione: A chemical and spectrophotometric investigation
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2-Mercapto-4,6-dimethylpyrimidine, as effective carboxyl activating group, has been successfully proved by converting it into respective acyl derivatives and the subsequent conversion to the amides and esters respectively using amines, amino alcohols and alcohols. The aminolysis and esterification were monitored chemically and spectrophotometrically. This paved way to establish that the above mercaptopyrimidine derivative is an efficient carboxyl activating group applicable in solid phase peptide synthesis.
- Rajan
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p. 287 - 291
(2015/01/30)
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- A new gold-catalysed azidation of allenes
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A new gold-catalysed azidation reaction of allenes is presented as a new highly modular approach for the synthesis of substituted allyl derivatives containing nitrogen from simple precursors. This journal is The Royal Society of Chemistry.
- Hurtado-Rodrigo, Cesar,Hoehne, Stefanie,Munoz, Maria Paz
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supporting information
p. 1494 - 1496
(2014/02/14)
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- The oxidation of the alpha-carbon of amines in hydrothermal condition: An alternative synthetic route of compounds containing amide bond
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Here we report experimental evidence for the simple synthesis of N,N-diethylhydroxylamine and an amide bond formation reaction from oxidation of the alpha-carbon of tertiary amines by the reaction of triethylamine and hydrogen peroxide in hydrothermal conditions. It is proved that 120 C is a turning point: when the temperature is lower than that, the main product is N,N-diethylhydroxylamine as a result of a cope rearrangement reaction mechanism; on the contrary, the product is more complex and the main products are amides via a radical chain mechanism involving three steps: initiation, propagation, and oxidation, followed by decarbonylation and electrocyclization because the radical is easier to form under high temperature.
- Bai, Xueyin,Liu, Ziwei,Ye, Kaiqi,Wang, Yu,Zhang, Xianlong,Yue, Huijuan,Tian, Ge,Feng, Shouhua
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p. 319 - 321
(2014/01/06)
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- A mild, aromatization of cyclic compounds and oxidation of amino groups to carbonyls using o-iodoxybenzoic acid
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A new, mild and efficient method has been developed for the synthesis of aromatic compounds and some carbonyls via the oxidative aromatization of amino cyclic compound by using hypervalent iodine reagent in DMSO at ambient temperature. The facile synthetic accessibility and it is as mild as non-hazardous nature render o-iodoxybenzoic acid equivalent of Dess-Martin periodinane reagent in organic oxidations.
- Kacan,Cicek,Karabulut,Ozyildirim
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p. 7649 - 7650
(2013/08/23)
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- Chemoselective amide formation using O-(4-nitrophenyl)hydroxylamines and pyruvic acid derivatives
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A series of O-(4-nitrophenyl)hydroxylamines were synthesized from their respective oximes using a pulsed addition of excess NaBH3CN at pH 3 in 65a-75% yield. Steric hindrance near the oxime functional group played a key role in both the ease by which the oxime could be reduced and the subsequent reactivity of the respective hydroxylamine. Reaction of the respective hydroxylamines with pyruvic acid derivatives generated the desired amides in good yields. A comparison of phenethylamine systems bearing different leaving groups revealed significant differences in the rates of these systems and suggested that the leaving group ability of the Na-OR substituent plays an important role in determining their reactivity with pyruvic acid. Competition experiments (in 68% DMSO/phosphate buffered saline) using 1 equiv of N-phenethyl-O-(4-nitrophenyl)hydroxylamine and 2 equiv of pyruvic acid in the presence of other nucleophiles such as glycine, cysteine, phenol, hexanoic acid, and lysine demonstrated that significant chemoselectivity is present in this reaction. The results suggest that this chemoselective reaction can occur in the presence of excess α-amino acids, phenols, acids, thiols, and amines.
- Kumar, Sonali,Sharma, Rashi,Garcia, Megan,Kamel, Joseph,McCarthy, Caroline,Muth, Aaron,Phanstiel, Otto
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p. 10835 - 10845
(2013/02/23)
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- Continuous Method For Producing Fatty Acid Amides
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The invention relates to a continuous method for producing fatty acid amides, according to which at least one fatty acid of formula (I), [in-line-formulae]R3—COOH??(I)[/in-line-formulae] wherein R3 is an optionally substituted aliphatic hydrocarbon radical, is reacted with at least one amine of formula (II), [in-line-formulae]HNR1R2??(II)[/in-line-formulae] wherein R1 and R2 are independently hydrogen or a hydrocarbon radical comprising between 1 and 100 C atoms, to form an ammonium salt, and said ammonium salt is then reacted to form a fatty acid amide, under microwave irradiation in a reaction pipe, the longitudinal axis of the pipe being oriented in the direction of propagation of the microwaves of a monomode microwave applicator.
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Page/Page column 9
(2011/05/03)
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- Efficient iodine-mediated beckmann rearrangement of ketoximes to amides under mild neutral conditions
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Aryl ketoximes readily underwent Beckmann rearrangement to give N-substituted amides in excellent yields on electrophilic activation by elemental iodine in anhydrous acetonitrile under reflux. The main advantages of this environmentally friendly protocol include a high selectivity as a result of the absence of any accompanying deprotection to form the parent ketones as byproducts, mild neutral conditions, procedural simplicity, and particularly ease of isolation of the products.
- Ganguly, Nemai C.,Mondal, Pallab
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experimental part
p. 3705 - 3709
(2011/01/03)
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- PROCESS FOR STRAIGHTENING KERATIN FIBRES WITH A HEATING MEANS AND DENATURING AGENTS
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The invention relates to a process for straightening keratin fibres, comprising: (i) a step in which a straightening composition containing at least two denaturing agents is applied to the keratin fibres, (ii) a step in which the temperature of the keratin fibres is raised, using a heating means, to a temperature of between 110 and 250° C.
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- CeCl3·7H2O-NaI/SiO2 promoted Beckmann rearrangement (under solvent-free and microwave irradiation)
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CeCl3·7H2O-NaI/SiO2 system promoted Beckmann rearrangement of a variety of aldoximes and ketoximes was efficiently conducted under solvent-free and microwave irradiation conditions. This protocol afforded an alternative method for the preparation of amides by Beckmann rearrangement with advantages of short reaction time, high yield, no pollution, simple operation and easy work-up.
- Li, Zheng,Lu, Zhong,Ding, Runbo,Yang, Jingya
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p. 668 - 670
(2007/10/03)
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- Sulfamic acid as a cost-effective and recyclable catalyst for liquid Beckmann rearrangement, a green process to produce amides from ketoximes without waste
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Sulfamic acid (H2NSO3H) has been proved to be an efficient and green catalyst for liquid Beckmann rearrangement of ketoxime in dried acetonitrile. The use of basic neutralization agent has been avoided in this system due to its intrinsic zwitterionic property. Thus it is a green process for preparation of amide from ketoxime without producing any waste.
- Wang, Bo,Gu, Yanlong,Luo, Cheng,Yang, Tao,Yang, Liming,Suo, Jishuan
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p. 3369 - 3372
(2007/10/03)
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- Synthesis and pyrolysis of tetrahydro-1,4-oxazine-3,5-diones and tetrahydro-1,4-thiazine-3,5-diones
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The preparation and characterization of six 4-substituted tetrahydro-l,4-oxazine-3,5-diones and five 4-substituted tetrahydro-l,4-thiazine-3,5-diones is described. Upon flash vacuum pyrolysis at 700°C these give N-substituted acetamides and nitriles, and a mechanism for formation of these products is proposed.
- Aitken,Farrell,Kirton
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p. 1526 - 1531
(2007/10/03)
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- A facile beckmann rearrangement of oximes with AlCl3 in the solid state
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A facile and efficient synthetic procedure, for Beckmann rearrangement of oximes with AlCl3 in the absence of solvent is developed. We have been able to convert cyclohexanone oxime to εcaprolactam in a quantitative yield.
- Ghiaci,Hassan Imanzadeh
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p. 2275 - 2280
(2007/10/03)
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- Phosphoryl to carbonyl migration of amino groups in mixed anhydrides
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Mixed anhydrides derived from carboxylic and aminophosphoric acids, (RO)(R'2N)P(O)OC(O)R'' (1), undergo unimolecular fragmentation yielding carboxyamides, R''C(O)NR'2, and metaphosphate esters, ROPO2.The mechanism of the amino group transfer was studied for substrate 1a (1, R = R' = Me; R'' = Ph); solvent as well as substituent effects indicate little (if any) charge development in the transition state.The effects of solvents and Lewis acids on the reaction rate and the activation parameters determined for 1a can be explained best in terms of stabilizing interactions with either carboxyamide or metaphosphate being formed in the course of reaction.The transfer of a functional group from one acyl center to another was investigated for other anhydride systems and the relative contributions of the fragmentation vs. disproportionation of substrates are discussed.
- Symes, Jill,Modro, Tomasz A.
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p. 1702 - 1708
(2007/10/02)
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- The Selective N-Monoalkylation of Amides with Alkyl Halides in the Presence of Alumina and KOH
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The effects of alumina impregnated with KOH (KOH/Al2O3) and a mixture of alumina and powdered KOH (KOH+Al2O3) have been examined using the alkylation of benzamide under various conditions.In each case, alkylation occurs exclusively in the pores of the alumina, the extent depending upon the alumina-pore size.For both yield and selectivity for N-monoalkylation, KOH+Al2O3 is superior to KOH/Al2O3.Dioxane is the best of the solvents employed.It is proposed that, in dioxane, an enolate-like species, PhC(O-K+)=NR', exists as stable ion pair aggregates, which are true reactants in the pore.This method, using KOH/Al2O3 or KOH+Al2O3, has been applied to N-alkylation of the other amides, giving the N-monoalkylated products in substantial yields with extremely high selectivities. 2-Phenylacetamide is regioselectively N-monoalkylated in high yields.This regioselectivity is explained in terms of steric hindrance.
- Sukata, Kazuaki
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p. 838 - 843
(2007/10/02)
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- Nucleophilic Reactivity toward Acetyl Chloride in Water
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Rate constant ratios for the reactions of acetyl chloride with nucleophilic reagents in water containing 2.5percent (v/v) dioxane were determined by product analysis.The rate constants show a small dependence on the basicity of primary amines, with βnuc=0.25, and are assigned to rate-limiting attack of the nucleophile.Pyridines with pKa>5 behave similarly, with βnuc=0.24, but less basic pyridines react more slowly.Several "α-effect" amines and anionic oxygen nucleophiles show small rate enhancements that are attributed to increases in the rate of nucleophilic attack.The rate constants do not fit the N+ correlation equation, and it is concluded that the reactions of nucleophilic reagents with acyl compounds are not satisfactorily correlated by simple modifications of this equation.
- Palling, David J.,Jencks, William P.
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p. 4869 - 4876
(2007/10/02)
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- Polar Effects in Free-Radical Reactions. Carbamoylation and α-N-Amidoalkylation of Heteroaromatic Bases by Amides and Hydroxylamine-O-sulfonic Acid.
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The decomposition by Fe(II) salt of hydroxylamine-O-sulfonic acid (HSA) in the presence of formamide, alkylformamides, and N-alkylacetamides provides the amino radical cation *+NH3, which by hydrogen abstraction generates carbamoyl (*CON) and α-N-amidoalkyl (CON*C) radicals.Both kinds of radicals have a clear-cut nucleophilic character and selectively attack protonated heteroaromatic bases, such as 4-methylquinoline or quinoxaline, in the α-position or are oxidized by Fe(III) salts.Redox chain mechanisms are involved.The importance of the polar effects in the hydrogen abstraction, aromatic substitution, and oxidation by Fe(III) salt is discussed.
- Citterio, Attilio,Gentile, Anna,Minisci, Francesco,Serravalle, Marco,Ventura, Susanna
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p. 3364 - 3367
(2007/10/02)
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- Solute-Solute Interactions in Non-aqueous Solvents. Enthalpic Interaction Coefficients of Substituted Acetamides Dissolved in N,N-Dimethylformamide
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Enthalpies of dilution of acetamide, N-methylacetamide, N-ethylacetamide, N-propylacetamide, N-butylacetamide, N,N-dimethylacetamide, N,N-diethylacetamide, N,N-dipropylacetamide and N,N-dibutylacetamide dissolved in N,N-dimethyacetamide as solvent have been measured calorimetrically at 25 deg C.The results are interpreted in terms of McMillan-Mayer theory.The enthalpic interaction parameters are obtained for pairs, triplets and some quadruplets of solute molecules.All enthalpic pair interaction coefficients but one in this nonaqueous solvent are negative, whereas the triplet coefficients are positive.The concept of "solvophobic interaction" can be used to explain these results in connection with the assumption of the formation of solute-solvent associates.The enthalpic pair interaction coefficients can be described by the additivity approach of Savage and Wood.
- Bloemendal, M.,Somsen, G.
-
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- RUTHENIUM CATALYZED N-ALKYLATION OF AMIDES WITH ALCOHOLS.
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Amides reacted with primary alcohols in the presence of a catalytic amount of RuCl//2(PPh//3)//3 at 180 degree C to give the corresponding N-monoalkyl amides in fairly good yields. Thus, benzamide reacted with l-octanol to give N-octylbenzamide in 76% yield with excellent product selectivity. Little esterification of amides with alcohols occurred and selectivity to the N-alkylation was high. Most of the amides gave N-monoalkyl amides but no N,N-dialkyl amides. But formamide reacted with l-butanol to give N,N-dibutylformamide, as well as N-butylformamide, in low yield. RuCl//2(PPh//3)//3 was the most effective catalyst for this reaction and RuHCl(PPh//3)//3 also had some catalytic activity.
- Watanabe,Ohta,Tsuji
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p. 2647 - 2651
(2007/10/02)
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- NEW SYNTHETIC "TRICKS" USING OLD REAGENTS. A MILD METHOD FOR THE CONVERSION OF RCONHR' TO RCONHR''
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N-Alkyl-N-nitrosoamides, RCON(NO)R'react with primary aliphatic amines (NH2R''), in refluxing dichloromethane or at room temperature, to give RCONHR'' in 65-98percent yields.
- Garcia, Jordi,Vilarrasa, Jaume
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p. 1127 - 1128
(2007/10/02)
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- OXIDATION-REDUCTION MECHANISMS - INNER-SPHERE AND OUTER-SPHERE ELECTRON TRANSFER IN THE REDUCTION OF IRON(III), RUTHENIUM(III), AND OSMIUM(III) COMPLEXES BY ALKYL RADICALS. MECHANISMS -
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Alkyl radicals are readily oxidized by the tris(phenanthroline) and tris(bipyridine) complexes ML//3**3** plus of iron(III), ruthenium(III), and osmium(III) in acetonitrile solution, the second-order rate constants easily exceeding 10**6 M** minus **1s** minus **1 at 25 degree C. Two oxidative processes are identified as (a) ligand substitution on the coordinated 1,10-phenanthroline to yield various alkylphenanthrolines and (b) cation formation to afford alkenes and N-alkylacetamides (after hydrolysis). Cation formation is characterized by extensive skeletal rearrangement of neopentyl, isobutyl, and n-propyl groups, whereas ligand substitution by the same alkyl radicals occurs without any rearrangement.
- Rollick,Kochi
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p. 1319 - 1330
(2007/10/02)
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- The photochemical addition of N-haloamides to olefins: the influence of various factors on the competition between 1,2-addition and hydrogen abstraction
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In the photodecomposition of N-haloamides (ZCONRX) in the presence of olefins, the 1,2-addition chain competes with the hydrogen abstraction chain(s) leading to the parent amide (the quantum yields for these processes are greater than unity).The following factors were shown to have an influence on this competition as measured by the yield of 1,2-addition and the yield of parent amide in methylene chloride solutions: (i) the N-halogen (higher yields of addition with X=Cl than with X=Br); (ii) the electronegativity of Z (increase of the yield of addition as the electronegativity of Z increases); (iii) the temperature (higher yields of addition at lower temperatures, and at -70 degC, better yields of addition (>90percent, R=H) for X=Br than for X=Cl); and (iv) the size of R (dramatic decrease of the yield of 1,2-addition in going from R=H to R=CH3).Surprisingly, the presence of a scavenger for HX had no influence on the yield of 1,2-addition.Both the size and electronegativity of Z had an effect on the stereochemistry of 1,2-addition to cyclohexene.High yields of addition to a variety of olefins were obtained with N-chloroamides such as ClCH2CONHCl, C2H5OCONHCl, CF3CONHCl.Their addition to enol ethers at -70 degC led to the synthesis of α-amido acetals or ketals (aldehydes or ketones) and to an α-amido glycoside in good yields.
- Lessard, Jean,Mondon, Martine,Touchard, Daniel
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p. 431 - 450
(2007/10/02)
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- The kinetics and mechanism of acid catalysed hydrolysis of lactams
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The acid-catalysed hydrolysis of lactams of ring size 4-7, and of N-ethylacetamide, has been studied at various temperatures in 0-70percent aqueous sulfuric acids.The kinetics have been analysed by means of the r-hydration parameter treatment and the transition-state activity coefficient (TSAC) approach.Except for the β-lactam, all substrates show a strong positive rate dependence on water activity, indicating a tetrahedral intermediate type of mechanism (A0T2), similar to that found for simple (acyclic) amide hydrolyses; only the β-lactam shows a negative rate - water activity dependence, which is interpreted in terms of a unimolecular (AND1) mechanism, involving rate-determining acylium ion formation.Similarly, all substrates except the β-lactam show a pronounced destabilization of the transition-state as acidity is increased, typical of oxonium ion species.The behaviour of the β-lactam resembles that of methyl mesitoate hydrolysis.Basicity constants for lactams of ring size 4-9 show a definite dependence on ring size, with the δ-lactam being unusually basic.Both rate and pK dependence on ring size are discussed in terms of ring strain and steric effects.The activation parameters, particularly ΔS, are fully consistent with the conclusions drawn concerning transition-state hydration.
- Wan, Peter,Modro, Tomasz A.,Yates, Keith
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p. 2423 - 2432
(2007/10/02)
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