- Metal array fabrication based on ultrasound-induced self-assembly of metalated dipeptides
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Pd- and Pt-bound bis-metalated peptides were synthesised by the condensation of Pd- or Pt-aldimine-complex-bound glutamic acids to afford the four possible metal isomers of bis-Pd and bis-Pt-homometalated dipeptides and PdPt- and PtPd-heterometalated dipeptides without metal disproportionation. Ultrasound-induced self-assembly of these bis-metalated peptides proceeded effectively to afford supramolecular gels that displayed well-ordered metal arrays. The formation of parallel β-sheet type aggregates through interpeptide amide-amide hydrogen bonding was confirmed by IR, scanning electron microscopy (SEM), and synchrotron X-ray diffraction analyses (WAXS and SAXS). The mechanism of the ultrasound-induced self-assembly of the metalated dipeptides was elucidated via kinetic and association experiments by 1H NMR, in which ultrasound-triggered dissociation of intramolecular hydrogen bonds between the chloride ligands of the Pd- and Pt-complexes and amides initially occurred. This was followed by the formation of intermolecular amide-amide hydrogen bonds, which afforded the corresponding oligomeric peptide self-assembly as the nucleus for supramolecular aggregation. The observed first-order relationship of the gelation rate versus the sonication frequency suggested that the microcavitation generated under sonication conditions acted as a crucial trigger and provided a reaction field for efficient self-assembly.
- Isozaki, Katsuhiro,Haga, Yusuke,Ogata, Kazuki,Naota, Takeshi,Takaya, Hikaru
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Read Online
- A photochemical C=C cleavage process: Toward access to backbone N-formyl peptides
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Photo-responsive modifications and photo-uncaging concepts are useful for spatiotemporal control of peptides structure and function. While side chain photo-responsive modifications are relatively common, access to photo-responsive modifications of backbone N-H bonds is quite limited. This letter describes a new photocleavage pathway, affording N-formyl amides from vinylogous nitroaryl precursors under physiologically relevant conditions via a formal oxidative C=C cleavage. The N-formyl amide products have unique properties and reactivity, but are difficult or impossible to access by traditional synthetic approaches.
- Ball, Zachary T.,Wang, Haopei
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p. 2932 - 2938
(2022/01/12)
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- Amide bond formation in aqueous solution: Direct coupling of metal carboxylate salts with ammonium salts at room temperature
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Herein, we report a green, expeditious, and practically simple protocol for direct coupling of carboxylate salts and ammonium salts under ACN/H2O conditions at room temperature without the addition of tertiary amine bases. The water-soluble coupling reagent EDC·HCl is a key component in the reaction. The reaction runs smoothly with unsubstituted/substituted ammonium salts and provides a clean product without column chromatography. Our reaction tolerates both carboxylate (which are unstable in other forms) and amine salts (which are unstable/volatile when present in free form). We believe that the reported method could be used as an alternative and suitable method at the laboratory and industrial scales. This journal is
- Nielsen, John,Tung, Truong Thanh
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supporting information
p. 10073 - 10080
(2021/12/10)
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- Catalytic asymmetric [3+2] cycloaddition of isomünchnones with methyleneindolinones
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An efficient enantioselective [3+2] cycloaddition of isomünchnones with methyleneindolinones that are generated by anin situintramolecular addition of the carbonyl group to rhodium carbenes is realized with a chiralN,N′-dioxide/Zn(ii) complex as a Lewis acid. A series of chiral oxa-bridged 3-spiropiperidines are obtained in high yields with excellent dr and excellent ee values.
- Feng, Xiaoming,Hu, Xinyue,Lin, Lili,Wang, Kaixuan,Xu, Chaoran,Zhou, Yuqiao
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supporting information
p. 8917 - 8920
(2021/09/10)
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- An Electrochemical Beckmann Rearrangement: Traditional Reaction via Modern Radical Mechanism
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Abstract: Electrosynthesis as a potential means of introducing heteroatoms into the carbon framework is rarely studied. Herein, the electrochemical Beckmann rearrangement, i. e. the direct electrolysis of ketoximes to amides, is presented for the first time. Using a constant current as the driving force, the reaction can be easily carried out under neutral conditions at room temperature. Based on a series of mechanistic studies, a novel radical Beckmann rearrangement mechanism is proposed. This electrochemical Beckmann rearrangement does not follow the trans-migration rule of the classical Beckmann rearrangement.
- Tang, Li,Wang, Zhi-Lv,He, Yan-Hong,Guan, Zhi
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p. 4929 - 4936
(2020/08/21)
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- ZnFe-LDH/GO nanocomposite coated on the glass support as a highly efficient catalyst for visible light photodegradation of an emerging pollutant
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This study reports the fabrication of ZnFe-layered double hydroxides with sulfate-intercalated anion (ZnFe-SO4-LDH) modified with graphene oxide (GO) by chemical co-precipitation method. They were then coated on the glass substrates (denoted as ZnFe-LDH/GO/GS). The XRD, SEM, EDX, X-ray Dot-mapping, FTIR, AFM, UV–Vis DRS, and PL analyses were used for the characterization of the as-synthesized sample. The photocatalytic implementation of the as-prepared photocatalyst was scrutinized for the degradation of phenazopyridine hydrochloride (PhP) from the solution under visible light irradiation. The prepared photocatalyst showed photocatalytic performance of elimination PhP, the degraded rate of pollutant could reach 60.01% in 150 min of photocatalysis process under the optimum conditions: initial PhP concentration of 15 mg/L, pH of 8 (natural pH), and 3 photocatalysts plates. The addition of 1 mmol/L of potassium persulfate (k2S2O8) caused the degradation efficiency of 93.95% within the 150 min of photocatalytic process. Trapping experiments indicated the influence order of O2 ?· > [rad]OH > h+ for the ROSs present in decomposition. The transformation of five intermediates of PhP produced in the photocatalytic degradation process was identified by the GC–MS technique. 60% COD removal efficiency was achieved after 300 min of photocatalytic reaction confirming mineralization of the PhP solution. Finally, a reusability test of ZnFe-LDH/GO/GS photocatalyst in the PhP degradation revealed that almost 12% drop occurred after five successive cycles.
- Motlagh, Parisa Yekan,Khataee, Alireza,Hassani, Aydin,Sadeghi Rad, Tannaz
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- An unexpected new pathway for nitroxide radical production via more reactve nitrogen-centered amidyl radical intermediate during detoxification of the carcinogenic halogenated quinones by N-alkyl hydroxamic acids
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We found previously that nitroxide radical of desferrioxamine (DFO?) could be produced from the interaction between the classic iron chelating agent desferrioxamine (DFO, an N-alkyl trihydroxamic acid) and tetrachlorohydroquinone (TCHQ), one of the carconogenic quinoind metabolites of the widely used wood preservative pentachlorophenol. However, the underlying molecular mechanism remains unclear. Here N-methylacetohydroxamic acid (N-MeAHA) was synthesized and used as a simple model compound of DFO for further mechanistic study. As expected, direct ESR studies showed that nitroxide radical of N-MeAHA (Ac-(CH3)NO?) can be produced from N-MeAHA/TCHQ. Interestingly and unexpectedly, when TCHQ was substituted by its oxidation product tetrachloro-1,4-benzoquinone (TCBQ), although Ac-(CH3)NO? could also be produced, no concurrent formation of tetrachlorosemiquinone radical (TCSQ?) and TCHQ was detected, suggesting that Ac-(CH3)NO? did not result from direct oxidation of N-MeAHA by TCSQ? or TCBQ as proposed previously. To our surprise, a new nitrogen-centered amidyl radical was found to be generated from N-MeAHA/TCBQ, which was observed by ESR with the spin-trapping agents and further unequivacally identified as Ac-(CH3)N? by HPLC-MS. The final product of amidyl radical was isolated and identified as its corresponding amine. Analogous radical homolysis mechanism was observed with other halogenated quinoid compounds and N-alkyl hydroxamic acids including DFO. Interestingly, amidyl radicals were found to induce both DNA strand breaks and DNA adduct formation, suggesting that N-alkyl hydroxamic acids may exert their potential side-toxic effects via forming the reactive amidyl radical species. This study represents the first report of an unexpected new pathway for nitroxide radical production via hydrogen abstration reaction of a more reactive amidyl radical intermediate during the detoxification of the carcinogenic polyhalogenated quinones by N-alkyl hydroxamic acids, which provides more direct experimental evidence to better explain not only our previous finding that excess DFO can provide effective but only partial protection against TCHQ (or TCBQ)-induced biological damage, and also the potential side-toxic effects induced by DFO and other N-alkyl hydroxamic acid drugs.
- Zhu, Ben-Zhan,Xu, Dan,Qin, Li,Huang, Chun-Hua,Xie, Lin-Na,Mao, Li,Shao, Jie,Kalyanaraman, Balaraman
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p. 150 - 159
(2019/11/28)
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- Regioselective Intramolecular Allene Amidation Enabled by an EDA Complex**
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The addition of radicals to unsaturated precursors is a powerful tool for the synthesis of both carbo- and heterocyclic organic building blocks. The recent advent of mild ways to generate N-centered radicals has reignited interest in exploiting highly regio-, chemo-, and stereoselective transformations that employ these reactive intermediates. While the additions of aminyl, iminyl, and amidyl radicals to alkenes and alkynes have been well-studied, analogous additions to allenes are scarce. Allenes offer several attractive features, including potential for selective amidation at three distinct sites via judicious choice of precursor or radical source, the opportunity for axial-to-point chirality transfer, and productive trapping of vinyl or allyl radical intermediates to diversify functionality in the products. In this article, we report a regioselective addition of amidyl radicals to allenes to furnish an array of valuable N-heterocycle scaffolds.
- Liu, Lu,Ward, Robert M.,Schomaker, Jennifer M.
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p. 13783 - 13787
(2020/10/06)
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- Synthesis of diverse libraries of carboxamides via chemoselective N-acylation of amines by carboxylic acids employing Br?nsted acidic IL [BMIM(SO3H)][OTf]
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Chemoselective N-acylation of amines with carboxylic acids as acyl electrophiles and Br?nsted acidic IL [BMIM(SO3H)][OTf] as promoter is reported under both thermal and microwave irradiation to produce libraries of carboxamides in good to excellent yields after a simple workup. The protocol is compatible with structurally diverse 1° and 2° amines and works in the presence of sensitive functional groups such as thiols and phenols. The potential for recycling and reuse of the IL is also demonstrated.
- Savanur, Hemantkumar M.,Malunavar, Shruti S.,Prabhala, Pavankumar,Sutar, Suraj M.,Kalkhambkar, Rajesh G.,Laali, Kenneth K.
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supporting information
(2019/09/30)
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- Environment-friendly synthesis method of anthrapyridone dye
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The invention relates to an environment-friendly synthesis method of anthrapyridone dye. The method comprises the following steps: (1) adding ethyl acetate, monomethylamine and a phase transfer catalyst sequentially to a pressure vessel, and performing stirring for dissolution so as to obtain a first mixture; (2) heating the first mixture to 80-110 DEG C for a reaction, then performing cooling to40-70 DEG C, proceeding the reaction, performing pressure relief, determining the terminal point of the reaction, and performing cooling and filtration so as to obtain an intermediate A; (3) adding DMF, 1,4-dihydroxy anthraquinone and an auxiliary agent to the intermediate A, performing heating to 130-150 DEG C for a reaction, then performing cooling to 30-40 DEG C, and performing filtration so asto obtain an intermediate B; and (4) adding aromatic amine or alicyclic amine to the intermediate B, and performing a condensation reaction in the presence of boric acid until the terminal point. Through implementation of the environment-friendly synthesis method of anthrapyridone dye, good economic, social and ecologically environmental benefits can be achieved.
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Paragraph 0021-0027; 0029
(2019/05/15)
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- Anion–π Interactions in Light-Induced Reactions: Role in the Amidation of (Hetero)aromatic Systems with Activated N-Aryloxyamides
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The importance of anion–π interactions as a driving force for chemical and biological processes is increasingly being recognized. In this communication, we describe for the first time its key participation in light-induced reactions. We show, in particular, how transient complexes formed through noncovalent anion–π interactions between electron-poor N-aryloxyamides and multiply-charged anions (such as carbonate or phosphate) can undergo facile light-promoted N?O cleavage, affording amidyl radicals that can subsequently be trapped by (hetero)aromatics.
- Buglioni, Laura,Mastandrea, Marco M.,Frontera, Antonio,Pericàs, Miquel A.
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supporting information
p. 11785 - 11790
(2019/08/16)
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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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- 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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- Pivotal role of intramolecular catalysis in the selective acetylation of alkyl amines
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Preparation of amides by the use of esters as the "acyl donor" is less explored because they are less reactive and usually more steric demanding than conventional acid halides and anhydrides. Here, we report that 3-acetoxy-2-naphthoic acid, an aspirin analogue, can be used as a mild amine acetylating agent in ethanol at 25°C. The reaction is sensitive to steric and polar effects of the attacking amine, and the rate constants can be appropriately fitted by the Pavelich-Taft correlation. Density functional theory calculations used to study all reaction steps indicate that the o-carboxy group plays a pivotal role, guiding the attacking amine and accelerating the reaction. The reaction can be conveniently used for the acylation of a variety of primary and secondary amines.
- Nishida, Elvis N.,Vitto, Ramon,Peixoto, R?mulo C.R.,Nome, Faruk,Souza, Bruno S.
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- A Vinylogous Photocleavage Strategy Allows Direct Photocaging of Backbone Amide Structure
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Side-chain modifications that respond to external stimuli provide a convenient approach to control macromolecular structure and function. Responsive modification of backbone amide structure represents a direct and powerful alternative to impact folding and function. Here, we describe a new photocaging method using histidine-directed backbone modification to selectively modify peptides and proteins at the amide N-H bond. A new vinylogous photocleavage method allows photorelease of the backbone modification and, with it, restoration of function.
- Mangubat-Medina, Alicia E.,Martin, Samuel C.,Hanaya, Kengo,Ball, Zachary T.
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supporting information
p. 8401 - 8404
(2018/06/29)
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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 0036-0037
(2017/11/29)
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- A hydrophilic inorganic framework based on a sandwich polyoxometalate: Unusual chemoselectivity for aldehydes/ketones with in situ generated hydroxylamine
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A hydrophilic inorganic porous catalyst was prepared via the hydrothermal method. The combination of [WZn3(H2O)2(ZnW9O34)2]12- and Co(ii) provides a synergistical catalytic way to promote oximation of aldehyde/ketone with in situ generated hydroxylamine that initially produces an oxime, which further either dehydrates into a nitrile or undergoes a Beckmann rearrangement to form an amide.
- Xing, Songzhu,Han, Qiuxia,Shi, Zhuolin,Wang, Shugai,Yang, Peipei,Wu, Qiang,Li, Mingxue
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supporting information
p. 11537 - 11541
(2017/09/18)
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- Visible-Light-Mediated Synthesis of Amidyl Radicals: Transition-Metal-Free Hydroamination and N-Arylation Reactions
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The development of photoredox reactions of aryloxy-amides for the generation of amidyl radicals and their use in hydroamination-cyclization and N-arylation reactions is reported. Owing to the ease of single-electron-transfer reduction of the aryloxy-amides, the organic dye eosin Y was used as the photoredox catalyst, which results in fully transition-metal-free processes. These transformations exhibit a broad scope, are tolerant to several important functionalities, and have been used in the late-stage modification of complex and high-value N-containing molecules.
- Davies, Jacob,Svejstrup, Thomas D.,Fernandez Reina, Daniel,Sheikh, Nadeem S.,Leonori, Daniele
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supporting information
p. 8092 - 8095
(2016/07/16)
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- Phosphovanadomolybdic acid catalyzed desulfurization-oxygenation of secondary and tertiary thioamides into amides using molecular oxygen as the terminal oxidant
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In the presence of phosphovanadomolybdic acids, e.g., H6PV3Mo9O40, desulfurization-oxygenation of various kinds of structurally diverse secondary and tertiary thioamides proceeded efficiently using molecular oxygen as the terminal oxidant, affording the corresponding amides in moderate to excellent yields. In addition, 18O-labeled amides could readily be synthesized using H218O as the oxygen source.
- Xu, Ning,Jin, Xiongjie,Suzuki, Kosuke,Yamaguchi, Kazuya,Mizuno, Noritaka
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p. 4865 - 4869
(2016/07/06)
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- Fragmentation of Protonated N-(3-Aminophenyl)Benzamide and Its Derivatives in Gas Phase
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An ion of m/z 110.06036 (ion formula [C6H8NO]+; error: 0.32 mDa) was observed in the collision induced dissociation tandem mass spectrometry experiments of protonated N-(3-aminophenyl)benzamide, which is a rearrangement product ion purportedly through nitrogen-oxygen (N–O) exchange. The N–O exchange rearrangement was confirmed by the MS/MS spectrum of protonated N-(3-aminophenyl)-O18-benzamide, where the rearranged ion, [C6H8NO18]+ of m/z 112 was available because of the presence of O18. Theoretical calculations using Density Functional Theory (DFT) at B3LYP/6-31?g(d) level suggest that an ion-neutral complex containing a water molecule and a nitrilium ion was formed via a transition state (TS-1), followed by the water molecule migrating to the anilide ring, eventually leading to the formation of the rearranged ion of m/z 110. The rearrangement can be generalized to other protonated amide compounds with electron-donating groups at the meta position, such as, –OH, –CH3, –OCH3, –NH(CH3)2, –NH-Ph, and –NHCOCH3, all of which show the corresponding rearranged ions in MS/MS spectra. However, the protonated amide compounds containing electron-withdrawing groups, including –Cl, –Br, –CN, –NO2, and –CF3, at the meta position did not display this type of rearrangement during dissociation. Additionally, effects of various acyl groups on the rearrangement were investigated. It was found that the rearrangement can be enhanced by substitution on the ring of the benzoyl with electron-withdrawing groups. [Figure not available: see fulltext.]
- Zu, Chengli,Mukhopadhyay, Sukrit,Hanley, Patrick S.,Xia, Shijing,Bell, Bruce M.,Grigg, David,Gilbert, Jeffrey R.,O’Brien, John P.
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p. 917 - 926
(2016/05/02)
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- I2/Aqueous TBHP-Catalyzed Coupling of Amides with Methylarenes/Aldehydes/Alcohols: Metal-Free Synthesis of Imides
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We present a metal-free method for the synthesis of imides by the direct coupling of NH-amides with methylarenes under iodine/aqueous TBHP conditions. The optimized conditions worked very well with benzaldehydes and benzyl alcohol and furnished the corresponding imides in good to excellent yields. A series of control and radical scavenger experiments were also performed, which suggested the involvement of radical pathways. The labeling experiment in the presence of 18O-labeled H2O suggested water as a source of oxygen in the imides.
- Aruri, Hariprasad,Singh, Umed,Kumar, Sanjay,Kushwaha, Manoj,Gupta, Ajai Prakash,Vishwakarma, Ram A.,Singh, Parvinder Pal
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supporting information
p. 3638 - 3641
(2016/08/16)
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- An eco-friendly and highly efficient route for N-acylation under catalyst-free conditions
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An eco-friendly, simple, mild, chemoselective and highly efficient procedure for the acylation of primary and secondary amine function in various structurally and electronically aliphatic and aromatic compounds affording their corresponding N-Ac derivatives is developed. Mild conditions, simplicity and easier work-up are the main advantages of this method.
- Ouarna, Souad,K'tir, Hacène,Lakrout, Salah,Ghorab, Hamida,Amira, A?cha,Aouf, Zineb,Berredjem, Malika,Aouf, Nour-Eddine
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p. 913 - 919
(2015/10/28)
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- Highly efficient synthesis of amides from ketoximes using trifluoromethanesulphonic anhydride
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Trifluoromethanesulphonic anhydride (triflic anhydride: TA) has been successfully used as a reagent for Beckmann rearrangement in the conversion of a variety of ketoximes into amides without any additive or base. This reagent works well for the synthesis of a library of amides with excellent yields.
- Kalkhambkar, Rajesh G.,Savanur, Hemantkumar M.
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p. 60106 - 60113
(2015/07/27)
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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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- Direct catalytic synthesis of ε-caprolactam from cyclohexanol using [n-C16H33N (CH3)3]H2PW12O40 as a catalyst
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ε-Caprolactam was synthesized directly from cyclohexanol via a tandem catalytic process using [n-C16H33N(CH3)3]H2PW12O40 as a catalyst. The highly efficient performance of the catalysts is due to the phase-transfer function of cation, improved coordination with peroxotungsten during oxidation and stabilization function of heteropoly anion on the intermediate formed during Beckmann rearrangement. A ε-caprolactam yield of 73.9% was obtained with a cyclohexanol conversion of 97.1% under optimized conditions.
- Wang, Hefang,Hu, Rongbin,Yang, Yongfang,Gao, Meidan,Wang, Yanji
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- Alkene anti-Dihydroxylation with Malonoyl Peroxides
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Malonoyl peroxide 1, prepared in a single step from the commercially available diacid, is an effective reagent for the anti-dihydroxylation of alkenes. Reaction of 1 with an alkene in the presence of acetic acid at 40 °C followed by alkaline hydrolysis leads to the corresponding diol (35-92%) with up to 13:1 anti-selectivity. A mechanism consistent with experimental findings is proposed that accounts for the selectivity observed.
- Alamillo-Ferrer, Carla,Davidson, Stuart C.,Rawling, Michael J.,Theodoulou, Natalie H.,Campbell, Matthew,Humphreys, Philip G.,Kennedy, Alan R.,Tomkinson, Nicholas C. O.
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supporting information
p. 5132 - 5135
(2015/11/03)
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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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- One-pot oximation-Beckmann rearrangement of ketones and aldehydes to amides of industrial interest: Acetanilide, caprolactam and acetaminophen
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High yielding one-pot oximation-Beckmann rearrangement of ketones to amides in ktrifluoroacetic acid has been conducted on several ketones and aldehydes. The substrate reactivity showed to depend on both oximation and Beckmann rearrangement reaction rate. In this synthetic procedure, trifluoroacetic acid acts as solvent, acid catalyst and organocatalyst and can be easily recycled.
- Aricò, Fabio,Quartarone, Giuseppe,Rancan, Elia,Ronchin, Lucio,Tundo, Pietro,Vavasori, Andrea
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- SILICA PARTICLES COATED WITH BETA-CYCLODEXTRIN FOR THE REMOVAL OF EMERGING CONTAMINANTS FROM WASTEWATER
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Provided is a silica particle coated with β-cyclodextrin, wherein said cyclodextrin is attached to said silica particle via at least one crosslinking agent and/or at least one copolymer. Also provided are methods of removing contaminants from a flowing or stationary liquid phase comprising the step of contacting said liquid phase with the silica particle coated with β-cyclodextrin.
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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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- Heterogeneous Beckmann rearrangements catalyzed by a sulfonated imidazolium salt of phosphotungstate
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The heteropolyanion-based ionic liquid (IL) material [MIMPS] 3PW12O40, propane sulfoacid-functionalized imidazolium salt of phosphotungstate, was used as a solid catalyst for liquid-phase Beckmann rearrangements of ketoximes in the presence of zinc chloride. The resultant liquid-solid biphasic rearrangement reaction of cyclohexanone oxime shows a high yield 83 % with good recyclability. The testing of control catalysts, reaction conditions, oxime substrates, and recycling property were carried out and the results are discussed. Graphical Abstract: The heteropolyanion-based ionic liquid (IL) material [MIMPS]3PW 12O40, propane sulfoacid-functionalized imidazolium salt of phosphotungstate, was used as a solid catalyst for liquid-phase Beckmann rearrangements of ketoximes in the presence of zinc chloride. The resultant liquid-solid biphasic rearrangement reaction of cyclohexanone oxime shows a high yield 83% with good recyclability. The testing of control catalysts, reaction conditions, oxime substrates, and recycling property were carried out, and the results are discussed.[Figure not available: see fulltext.]
- Zhang, Xuan,Mao, Dan,Leng, Yan,Zhou, Yu,Wang, Jun
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p. 193 - 199
(2013/03/13)
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- Efficient synthesis of N-methylamides and amines via 4-(alkylamino)benzyl- N-methylamine as a new protecting group
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4-(Alkylamino)benzyl-N-methylamine is a good protecting group for the synthesis of N-methylamides and amines. The N-debenzylation of N-methylamides and amines can be carried out selectively and efficiently under condition using trifluoroacetic acid (TFA).
- Lee, Sang-Hak,Mu, Yu,Kim, Gun-Woo,Kim, Jin-Seok,Park, Seok-Hwi,Jin, Tian,Lee, Kee-Young,Ham, Won-Hun
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p. 1749 - 1764
(2013/09/12)
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- Tuning the solid-state emission of the analogous GFP chromophore by varying alkyl chains in the imidazolinone ring
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New analogues of green fluorescent protein (GFP) chromophore m GFP-C n (n = 1, 3, 5, 11) with alkyl chains of different lengths in the imidazolinone rings were synthesized and their crystal structures were determined. These GFP-like chromophores are all emissive in the solid state. And the solid-state emission quantum yields of increase by extending the lengths of alkyl chains, owing to the fact that the intermolecular pi-pi interactions are significantly weakened based on their crystal structures.
- Shen, Xiang,Huang, Guangxi,Li, Kan,Zhang, Guanxin,Zhang, Deqing
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p. 1197 - 1203
(2013/09/23)
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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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- Isopropenyl acetate, a remarkable, cheap and acylating agent of amines under solvent- and catalyst-free conditions: A systematic investigation
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Isopropenyl acetate was proved to be an efficient reagent for acetylation of amine in the absence of solvent and catalyst. The corresponding acetamides were obtained in very high yields without any purification.
- Pelagalli, Romina,Chiarotto, Isabella,Feroci, Marta,Vecchio, Stefano
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supporting information; experimental part
p. 2251 - 2255
(2012/09/08)
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- C-H bond amination by photochemically generated transient borylnitrenes at room temperature: A combined experimental and theoretical investigation of the insertion mechanism and influence of substituents
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A number of azidoboranes having substitution patterns that are derived from catechol (3), pinacol (4a), 1,2-diaminoethane (4b,c), 1,2-ethanedithiol (4d), and 1,2,4,5-tetrahydroxybenzene as well as acyclic dialkoxy species (5) were synthesized and, in the case of 4c (N,N′-ditosyl-2-azido-1,3,2- diazaborolane), also structurally characterized. The azidoboranes were photolyzed in cyclohexane solvent in order to investigate the tendency of the generated borylnitrenes to undergo intermolecular C-H insertion reactions. The yields of intermolecular insertion products ranged from very good (4a) to vanishingly small, depending on the substitution of the azidoborane. For a number of borylnitrenes the zero-field splitting parameter D was measured in organic glasses at 4 K. The small primary kinetic isotope effect (k H/kD = 1.35) measured for 4a in mixtures of [H 12]cyclohexane and [D12]cyclohexane suggests that the insertion reaction is concerted and involves the singlet state of the borylnitrene. Computations at the CBS-QB3 and CCSD(T)/TZ2P levels of theory show that the relative energies of singlet and triplet states of a wide variety of borylnitrenes and even their nature as minima or saddle points depend strongly on the substituents. Photolysis of the most reactive azidoborane, 4a, in methane in a flow reactor at atmospheric pressure produces an intermolecular insertion product in low yields, in agreement with the expectation of intersystem crossing to the less reactive triplet state of the borylnitrene.
- Filthaus, Matthias,Schwertmann, Larissa,Neuhaus, Patrik,Seidel, Ruediger W.,Oppel, Iris M.,Bettinger, Holger F.
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experimental part
p. 3894 - 3903
(2012/07/13)
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- HEPATITIS C VIRUS NS3 PROTEASE INHIBITORS
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The present invention relates to macrocyclic compounds of Formula (I) that are useful as inhibitors of the hepatitis C virus (HCV) NS3 protease, their synthesis, and their use for treating or preventing HCV infections.
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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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- Vapor-phase Beckmann rearrangement of cyclohexanone oxime over halide cluster catalysts
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When a silica gel-supported tungsten halide cluster with an octahedral metal framework, (H3O)2[(W6Cl 8)Cl6]·6H2O/SiO2, is treated in a helium stream in the temperature range 250-350 °C, catalytic activity for the Beckmann rearrangement of cyclohexanone oxime develops. Niobium and tantalum clusters with the same metal framework also catalyze the reaction. Cyclopentanone oxime and acetone oxime also undergo Beckmann rearrangements over the tungsten cluster. The weak Br?nsted acidity (H0 ≈ +1.5) of the hydroxo ligand, which is developed on the activated cluster, is favorable for the rearrangement.
- Nagashima, Sayoko,Kamiguchi, Satoshi,Ohguchi, Satoshi,Chihara, Teiji
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experimental part
p. 135 - 138
(2012/02/03)
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- Bromodimethylsulfonium bromide (BDMS) in ionic liquid: a mild and efficient catalyst for Beckmann rearrangement
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Bromodimethylsulfonium bromide (BDMS)-catalyzed Beckmann rearrangement of a variety of ketoximes has been carried out in the imidazolium-based ionic liquid [bmim]PF6 under mild conditions without using any additional cocatalyst or solvent to afford excellent conversion and selectivity. The ionic liquid is recovered and reused for up to three runs without any loss of efficiency.
- Yadav, Lal Dhar S.,Garima,Srivastava, Vishnu P.
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scheme or table
p. 739 - 743
(2010/04/05)
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- Bromodimethylsulfonium bromide-ZnCl2: A mild and efficient catalytic system for beckmann rearrangement
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Bromodimethylsulfonium bromide, in combination with zinc chloride, has been shown to be an excellent catalytic system for liquid-phase Beckmann rearrangement of various ketoximes into the corresponding amides/lactams in acetonitrile at reflux temperature with good to excellent yields. Georg Thieme Verlag Stuttgart - New York.
- Yadav, Lal Dhar S.,Patel, Rajesh,Srivastava, Vishnu P.
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experimental part
p. 1771 - 1776
(2010/08/05)
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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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- A mild and efficient way to prepare ε-caprolactam by using a novel salt related with ionic liquids
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The Beckmann rearrangement of several ketoximes has been performed by treatment with tosyl chloride, using ionic liquids as both solvent and catalyst, without the need of any other promoter. High levels of conversion and selectivity were observed in the majority of experiments. Work-up is very simple and the product can be isolated in high yields. When the method was applied to cyclohexanone oxime, the novel salt [TMG][TsO] instead of the ionic liquid was used. This procedure afforded a conversion of 100% to obtain pure ε-caprolactam in a 98% yield. [TMG][TsO] is easy to prepare, cheap, and not corrosive. It can be recovered and reused.
- Vilas, Miguel,Tojo, Emilia
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experimental part
p. 4125 - 4128
(2010/08/19)
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- PROCESS FOR PREPARING SECONDARY AMIDES BY CARBONYLATION OF A CORRESPONDING TERTIARY AMINE
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The present invention relates to a process for preparing secondary amides with good selectivity by carbonylating a corresponding tertiary amine with carbon monoxide in a reaction mixture in the presence of a metal catalyst and in the presence of a halogen containing promoter. The metal catalyst comprises palladium. A same or even a much better catalytic activity can be obtained with palladium than with the much more expensive rhodium, especially when the palladium is used in a low concentration. Moreover, also a good selectivity can be achieved.
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Page/Page column 4
(2010/06/14)
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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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- Studies of the rates of thermal decomposition of glycine, alanine, and serine
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Rates of thermal decomposition of glycine, alanine, and serine are described by the equation of first order reaction in the temperature range 200-300°C. Apparent rate constants and apparent activation energies of decomposition of α-amino acids were evaluated. It was found that the main gaseos reaction product is carbon dioxide.
- Yablokov,Smel'tsova,Zelyaev,Mitrofanova
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body text
p. 1704 - 1706
(2011/05/14)
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- A facile synthesis of 2,3-disubstituted furo[2,3-b]pyridines
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In a three-step sequence starting from readily available starting materials, 2,3-carbon disubstituted furo[2,3-b]pyridines can be accessed in good yields and purity. Furo[2,3-b]pyridines bearing ester, amide and ketone groups at the 2-position can be prepared with a variety of aryl and alkyl groups at the 3-position.
- Beutner, Gregory L.,Kuethe, Jeffrey T.,Yasuda, Nobuyoshi
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supporting information; experimental part
p. 781 - 784
(2009/05/11)
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- FUSED POLYCYCLIC COMPOUNDS AND ORGANIC LIGHT-EMITTING DEVICE USING THE SAME
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A fused polycyclic compounds is represented by the general formula (I): wherein X1 to X18 each represent, independently of one another, a hydrogen atom, a halogen atom, a cyano group, a nitro group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted aralkyl group, a substituted amino group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group.
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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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