- Regio- and diastereoselective synthesis of trans-dihydrofuran-3carboxamides by radical addition of 1,3-dicarbonyl compounds to acrylamides using manganese(III) acetate and determination of exact configuration by X-ray crystallography
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In this study, we investigated the radical addition of 1,3-dicarbonyl compounds to acrylamide derivatives including phenyl, 2-thienyl and 5-methyl-2-furyl groups mediated by manganese(III) acetate. trans-3-Carboxamide-dihydrofurans were obtained in modarate to good yields, as well as regio- and diastereoselectievly. Structural analyses of these compounds were made by NMR techniques such as HMBC and NOSY spectra. Also, exact configuration and structures of these (7b, 7i and 7j) compounds were determined by X-ray crystallography.
- Yilmaz, Mehmet,Ustalar, Ash,U?an, Bedriye,Pekel, A. Tar?k
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Read Online
- Ammonium salts from polymer-bound N-hydroxysuccinimide as solid-supported reagents for EDC-mediated amidations
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New ammonium and alkylammonium salts derived from a polymeric N-hydroxysuccinimide (P-HOSu) have been prepared and used for the amidation of carboxylic acids and amino acids mediated by 1-ethyl-3-(3′-dimethylamino-propyl)carbodiimide hydrochloride (EDC). These polymer-supported ammonium salts afforded the corresponding amides in good yield, without detectable α-racemization and with easy recovery of the P-HOSu after the amidation reaction, being especially suitable for the amidation of Fmoc-protected amino acids.
- Chinchilla, Rafael,Dodsworth, David J.,Nájera, Carmen,Soriano, José M.
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- The HWE reaction in solid - liquid two phase system for the synthesis of α,β-unsaturated amides
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The Horner-Wadsworth-Emmons (HWE) reaction of the diethyl ester of 2-amino-2-oxoethylphosphonic acid 1 as well as of diethyl ester of the 2-dimethylamino-2-oxoethylphosphonic acid 2 with some aldehydes and ketones 3 in liquid-solid two phase system is used for the preparation of α,β-unsaturated amides 4, 5. The synthesis is carried out in mild conditions (room temperature, KOH, K2CO3, CaO) in the absence of a catalyst or in the absence of a solvent, and leads in very high (E)-stereoselectivity and in high yields to en-amides.
- Petrova, Jordanka,Momchilova, Snezhana,Vassilev, Nikolay G.
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- Facile and highly selective conversion of nitriles to amides via indirect acid-catalyzed hydration using TFA or AcOH-H2SO4
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(Chemical Equation Presented) Both aliphatic and aromatic nitriles are conveniently and selectively converted in a single step, via an indirect acid-catalyzed hydration, into the corresponding amides in 1-8 h using a TFA-H2SO4 mixture as a reagent system. Although the same reagent did not work for the sterically hindered nitriles such as mesitonitrile, the transformation could be accomplished by changing TFA to AcOH at higher temperatures (>90°C).
- Moorthy, Jarugu Narasimha,Singhal, Nidhi
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Read Online
- Iron-catalyzed hydroaminocarbonylation of alkynes: Selective and efficient synthesis of primary α,β-unsaturated amides
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α,β-Unsaturated primary amides are important intermediates and building blocks in organic synthesis. Herein, we report a ligand-free iron-catalyzed hydroaminocarbonylation of alkynes using NH4HCO3 as the ammonia source, enabling the highly efficient and regioselective synthesis of linear α,β-unsaturated primary amides. Various aromatic and aliphatic alkynes are transformed into the desired linear α,β-unsaturated primary amides in good to excellent yields. Further studies show that using NH4HCO3 as the ammonia source is key to obtain good yields and selectivity. The utility of this route is demonstrated with the synthesis of linear α,β-unsaturated amides including vanilloid receptor-1 antagonist TRPV-1.
- Huang, Zijun,Jiang, Xiongwei,Lan, Donghui,Li, Yuehui,Pi, Shaofeng,Tan, Zhengde,Tang, Jia,Xie, Tianle,Yi, Bing,Zhang, Minmin
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supporting information
(2022/02/22)
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- Nitrogen Atom Transfer Catalysis by Metallonitrene C?H Insertion: Photocatalytic Amidation of Aldehydes
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C?H amination and amidation by catalytic nitrene transfer are well-established and typically proceed via electrophilic attack of nitrenoid intermediates. In contrast, the insertion of (formal) terminal nitride ligands into C?H bonds is much less developed and catalytic nitrogen atom transfer remains unknown. We here report the synthesis of a formal terminal nitride complex of palladium. Photocrystallographic, magnetic, and computational characterization support the assignment as an authentic metallonitrene (Pd?N) with a diradical nitrogen ligand that is singly bonded to PdII. Despite the subvalent nitrene character, selective C?H insertion with aldehydes follows nucleophilic selectivity. Transamidation of the benzamide product is enabled by reaction with N3SiMe3. Based on these results, a photocatalytic protocol for aldehyde C?H trimethylsilylamidation was developed that exhibits inverted, nucleophilic selectivity as compared to typical nitrene transfer catalysis. This first example of catalytic C?H nitrogen atom transfer offers facile access to primary amides after deprotection.
- Schmidt-R?ntsch, Till,Verplancke, Hendrik,Lienert, Jonas N.,Demeshko, Serhiy,Otte, Matthias,Van Trieste, Gerard P.,Reid, Kaleb A.,Reibenspies, Joseph H.,Powers, David C.,Holthausen, Max C.,Schneider, Sven
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- Organocatalytic Trans Semireduction of Primary and Secondary Propiolamides: Substrate Scope and Mechanistic Studies
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We report a chemoselective, phosphine-catalyzed semireduction of primary and secondary propiolamides. In the presence of stoichiometric pinacolborane and catalytic n-tributylphosphine, a variety of propiolamides were successfully converted to the corresponding acrylamides in excellent yield with (E)-stereoselectivity. The reaction condition is tolerant of various functional groups including alkene, alkyne, ketone, or ester. Deuterium labeling studies established that the hydride from activated pinacolborane is added to the α-carbon and the proton on the amide nitrogen is abstracted by the ?-carbon to furnish the (E)-acrylamides. DFT calculations revealed a clear energetic driving force for the (E)- over the (Z)-isomer. (Figure presented.).
- Grams, R. Justin,Lawal, Monsurat M.,Szwetkowski, Connor,Foster, Daniel,Rosenblum, Carol Ann,Slebodnick, Carla,Welborn, Valerie Vaissier,Santos, Webster L.
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supporting information
p. 172 - 178
(2021/10/14)
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- Pd(II)-Catalyzed CC Bond Cleavage by a Formal Group-Exchange Reaction
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A chelation-assisted palladium-catalyzed CC bond cleavage of α, β-unsaturated ketone to form alkenyl nitrile in the presence of nitrile is disclosed on the basis of a formal group-exchange reaction formulated as C1C2 + C3 → C1C3 + C2, differing from normal alkene oxidative cleavage and metathesis type. The isolated key active Pd(II) complex as well as deuterium-labeled experiment revealed the necessity of the chelation group, and a plausible catalytic pathway was proposed.
- Ye, Runyou,Zhu, Maoshuai,Yan, Xufei,Long, Yang,Xia, Ying,Zhou, Xiangge
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p. 8678 - 8683
(2021/07/26)
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- Systematic study on acylation of methyl 3-aminocrotonate with acid chlorides of aliphatic, aromatic and α, β-unsaturated acids: A comparative evaluation of the preference for regio- And stereoselectivity vis-à-vis 3-aminocrotononitrile
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Acylation of methyl 3-aminocrotonate 1a in benzene with a variety of aliphatic and aromatic acid chlorides including α, β-unsaturated acid chloride in the presence of an added organic base, (either pyridine or triethylamine) is reported. The preferred N, C-site selectivity in these reactions has been compared with the terminal selectivity of the products obtained previously on acylation of methyl 3-aminocrotononitrile 1b. A strong preference either for N- or C- selectivity in N, C-acylation has been observed for both 1a and 1b based on the choice of acid chlorides and added organic base. Interestingly, irrespective of the enamine 1a or 1b, acylation with α, β-unsaturated acid chlorides in the presence of triethylamine afforded 3,4-dihydropyridin-(2H)-one via [3.3] sigmatropic rearrangement of the corresponding intermediary N(E)-enamide. Accrued results show methyl 3-aminocrotonate to be a better precursor for preparation of enamides (N-acylated products) whereas 3-aminocrotononitrile is found to be a preferred choice for preparation of enaminones (C-acylated products). An attempt is made to offer a preliminary theoretical interpretation for observed site selectivity.
- Mahalanabis, Kumar K.,Mukherjee, Attreyee
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p. 291 - 302
(2021/09/28)
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- Ruthenium-Catalyzed Oxidative Cross-Coupling Reaction of Activated Olefins with Vinyl Boronates for the Synthesis of (E, E)-1,3-Dienes
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An oxidative cross-coupling reaction between activated olefins and vinyl boronate derivatives has been developed for the highly stereoselective construction of synthetically useful (E,E)-1,3-dienes. The highlight of this reaction is that exclusive stereoselectivity (only E,E-isomer) was achieved from a base-free, ligand-free, and mild catalytic condition with a less expensive [RuCl2(p-cymene)]2 catalyst.
- Dethe, Dattatraya H.,Beeralingappa, Nagabhushana C.,Uike, Amar
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p. 3444 - 3455
(2021/02/16)
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- Manganese Catalyzed Enantioselective Epoxidation of α,β-Unsaturated Amides with H2O2
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Herewith, we report the enantioselective epoxidation of electron-deficient cis- and trans-α,β-unsaturated amides with the environmentally benign oxidant H2O2. The catalysts - manganese complexes with bis-amino-bis-pyridine and structurally related ligands - exhibit reasonably high efficiency (up to 100 TON) and excellent chemo- and enantioselectivity (up to 100% and 99% ee, respectively). Crucially, the cis-enamides epoxidation enantioselectivity and yield are dramatically enhanced by the presence of NH-moiety, which effect can be explained by the hydrogen bonding interaction between the cis-enamide substrate and the manganese based oxygen transferring species. (Figure presented.).
- Ottenbacher, Roman V.,Kurganskiy, Vladimir I.,Talsi, Evgenii P.,Bryliakov, Konstantin P.
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supporting information
p. 2778 - 2782
(2021/04/29)
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- Identification of a novel toxicophore in anti-cancer chemotherapeutics that targets mitochondrial respiratory complex i
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Disruption of mitochondrial function selectively targets tumour cells that are dependent on oxidative phosphorylation. However, due to their high energy demands, cardiac cells are disproportionately targeted by mitochondrial toxins resulting in a loss of cardiac function. An analysis of the effects of mubritinib on cardiac cells showed that this drug did not inhibit HER2 as reported, but directly inhibits mitochondrial respiratory complex I, reducing cardiac-cell beat rate, with prolonged exposure resulting in cell death. We used a library of chemical variants of mubritinib and showed that modifying the 1H-1,2,3-triazole altered complex I inhibition, identifying the heterocyclic 1,3-nitrogen motif as the toxicophore. The same toxicophore is present in a second anti-cancer therapeutic carboxyamidotriazole (CAI) and we demonstrate that CAI also functions through complex I inhibition, mediated by the toxicophore. Complex I inhibition is directly linked to anti-cancer cell activity, with toxicophore modification ablating the desired effects of these compounds on cancer cell proliferation and apoptosis.
- Allen, Timothy E. H.,Chung, Injae,Fischer, Peter,Hardy, Rachel,Harvey, Robert F.,Hirst, Judy,Kellam, Barrie,Macfarlane, Marion,Mistry, Sarah,Pryde, Kenneth R.,Serreli, Riccardo,Stephenson, Zo? A.,Stoneley, Mark,Willis, Anne E.
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- Contra-thermodynamic E → Z isomerization of cinnamamides via selective energy transfer catalysis
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A bio-inspired, photocatalytic E → Z isomerization of cinnamides is reported using inexpensive (?)-riboflavin (vitamin B2) under irradiation at λ = 402 nm. This operationally simple transformation is compatible with a range of amide derivatives including –NR2, –NHSO2R and N(Boc)2 (up to 99:1 Z:E). Selective energy transfer from the excited state photocatalyst to the starting E-isomer ensures that directionality is achieved: The analogous process with the Z-isomer is inefficient due to developing allylic strain causing chromophore deconjugation. This is supported by X-ray analysis and Stern-Volmer photo-quenching studies. Preliminary validation of the method in manipulating the conformation of a simple model Leu-enkephalin penta-peptide is disclosed via the incorporation of a cinnamamide-based amino acid.
- Becker, Marc R.,Morack, Tobias,Robertson, Jack,Metternich, Jan B.,Mück-Lichtenfeld, Christian,Daniliuc, Constantin,Burley, Glenn A.,Gilmour, Ryan
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- Donor-acceptor fluorophores as efficient energy transfer photocatalysts for [2 + 2] photodimerization
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Mild [2 + 2] photodimerization of enone substrates was induced by donor-acceptor fluorophores. Enone substrates were activated efficiently for anti-head to head dimerizations with a high yield (up to 83%) and high selectivity. The adjustable excited state potential also allows donor-acceptor fluorophores to be used for isomerization of the above substrates, confirming the potential of donor-acceptor fluorophores as energy transfer photocatalysts.
- Chen, Feng,Chen, Hao,Liu, Xue-Fen,Luo, Shu-Ping,Ren, Chen-Chao,Wu, Qing-An,Xu, Liang-Xuan,Yu, Xiao-Cong
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p. 3707 - 3716
(2020/06/03)
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- Pd-catalyzed oxidative Heck-type arylation of vinyl ketones, alkenes, and acrylates with Sb-aryl-tetrahydrodibenz[c,f][1,5]azastibocines
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The Pd-catalyzed cross-coupling reactions of Sb-aryl-1,5-azastibocines with alkenes are described. The reactions of azastibocines with alkenes such as vinyl ketones, alkenes, and acrylates in the presence of 10 mol% PdCl2 at 80 °C in DMA under aerobic conditions produced Heck adducts in moderate-to-excellent yields. Single-crystal X-ray and NMR analysis revealed that the aryl donors in this reaction, the Sb-aryl-1,5-azastibocines, are hypervalent compounds that display N–Sb intramolecular non-bonding interaction. These are the first examples of Pd-catalyzed Heck-type arylations using heterocyclic hypervalent organoantimony compounds. Although the reactions proceeded efficiently with the azastibocines, they hardly progressed with trivalent and pentavalent triarylantimony reagents.
- Murata, Yuki,Kakusawa, Naoki,Arakawa, Yukako,Hayashi, Yukako,Morinaga, Shun,Ueda, Masaaki,Hyodo, Tadashi,Matsumura, Mio,Yamaguchi, Kentaro,Kurita, Jyoji,Yasuike, Shuji
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- Catalytic, transition-metal-free semireduction of propiolamide derivatives: Scope and mechanistic investigation
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We report a transition-metal-free trans-selective semireduction of alkynes with pinacolborane and catalytic potassium tert-butoxide. A variety of 3-substituted primary and secondary propiolamides, including an analog of FK866, a potent nicotinamide mononucleotide adenyltransferase (NMNAT) inhibitor, are reduced to the corresponding (E)-3-substituted acrylamide derivatives in up to 99% yield with >99:1 E/Z selectivity. Mechanistic studies suggest that an activated Lewis acid-base complex transfers a hydride to the α-carbon followed by rapid protonation in a trans fashion.
- Grams, R. Justin,Garcia, Christopher J.,Szwetkowski, Connor,Santos, Webster L.
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supporting information
p. 7013 - 7018
(2020/09/12)
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- Nitromethane as a nitrogen donor in Schmidt-type formation of amides and nitriles
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The Schmidt reaction has been an efficient and widely used synthetic approach to amides and nitriles since its discovery in 1923. However, its application often entails the use of volatile, potentially explosive, and highly toxic azide reagents. Here, we report a sequence whereby triflic anhydride and formic and acetic acids activate the bulk chemical nitromethane to serve as a nitrogen donor in place of azides in Schmidt-like reactions. This protocol further expands the substrate scope to alkynes and simple alkyl benzenes for the preparation of amides and nitriles.
- Jiao, Ning,Liu, Jianzhong,Qiu, Xu,Song, Song,Wei, Jialiang,Wen, Xiaojin,Zhang, Cheng,Zhang, Ziyao
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supporting information
p. 281 - 285
(2020/01/28)
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- Amidoxime modified PAN supported palladium complex: A greener and efficient heterogeneous catalyst for heck reaction
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Development of a facile and greener approach for Heck reaction using a modified PAN supported palladium catalyst is described. The preparation of the catalyst involves a simple process through amidoxime modification of nitrile group in Polyacrylonitrile (PAN), followed by the complexation with Palladium chloride (PdCl2). The resulting supported catalyst was characterized by spectroscopic analyses and further by computational studies. This polymer supported Palladium complex displayed excellent catalytic activity in Heck coupling reaction of a series of activated alkenes and aryl halides and afforded the corresponding coupling products upto 96% isolated yield. After the reaction, the catalyst was easily recovered by simple filtration and recycled with excellent stability and activity even after 5 runs. This is the first report on the use of amidoxime functionalized PAN- Palladium (II) complex as a heterogeneous catalyst in Heck coupling reaction.
- Sruthi, Pambingal Rajan,Sarika, Vijayalekshmi,Suku, Arya,Krishnan, Aravind,Anas, Saithalavi
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- Water as a Hydrogenating Agent: Stereodivergent Pd-Catalyzed Semihydrogenation of Alkynes
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Palladium-catalyzed transfer semihydrogenation of alkynes using H2O as the hydrogen source and Mn as the reducing reagent is developed, affording cis- and trans-alkenes selectively under mild conditions. In addition, this method provides an efficient way to access various cis-1,2-dideuterioalkenes and trans-1,2-dideuterioalkenes by using D2O instead of H2O.
- Zhao, Chuan-Qi,Chen, Yue-Gang,Qiu, Hui,Wei, Lei,Fang, Ping,Mei, Tian-Sheng
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supporting information
p. 1412 - 1416
(2019/03/07)
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- Amidation of aldehydes using mono-cationic half-sandwich rhodium(III) complexes with functionalized phenylhydrazone ligands
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A series of mono-cationic half-sandwich rhodium(III) complexes have been synthesized in methanol using phenylhydrazone-derived ligands (L1–L6) and the starting precursor [(η5-C5Me5)2Rh2(μ-Cl)2Cl2] in a 2:1 molar ratio. The N,N′-phenylhydrazone complexes have been isolated as tetraphenylborate salts. All complexes were characterized by elemental analysis, FT-IR, UV–visible, NMR spectroscopy and mass spectrometry. The molecular structure of complex [(η5-C5Me5)Rh(L1)Cl](BPh4) (1) was confirmed by single-crystal X-ray structure analysis. Complex [(η5-C5Me5)Rh(L3)Cl](BPh4) (3) was used as an efficient catalyst for the amide formation reaction, with up to 99% conversion after 2 h in toluene at 110 °C in the presence of hydroxyl amine hydrochloride and sodium bicarbonate.
- Devika, Neelakandan,Ananthalakshmi, Subbiah,Raja, Nandhagopal,Gupta, Gajendra,Therrien, Bruno
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- Mechanochemical synthesis of primary amides from carboxylic acids using TCT/NH4SCN
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A facile and effective approach toward the synthesis of primary amides from carboxylic acids has been developed. In the presence of 2,4,6-trichloro-1,3,5-triazine, a combination of ammonium thiocyanate and potassium carbonate led to the rapid conversion of carboxylic acids into the corresponding amides within five minutes grinding at room temperature. The use of ammonium thiocyanate as the amine source is unprecedented and exclusive formation of primary amides is observed only under the liquid-assisted grinding conditions.
- Jaita, Subin,Phakhodee, Wong,Chairungsi, Neeranuch,Pattarawarapan, Mookda
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supporting information
p. 3571 - 3573
(2018/09/10)
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- Bioactivity and structure–activity relationship of cinnamic acid derivatives and its heteroaromatic ring analogues as potential high-efficient acaricides against Psoroptes cuniculi
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A series of cinnamic acid derivatives and its heteroaromatic ring analogues were synthesized and evaluated for acaricidal activity in vitro against Psoroptes cuniculi, a mange mite. Among them, eight compounds showed the higher activity with median lethal concentrations (LC50) of 0.36–1.07 mM (60.4–192.1 μg/mL) and great potential for the development of novel acaricidal agent. Compound 40 showed both the lowest LC50 value of 0.36 mM (60.4 μg/mL) and the smallest median lethal time (LT50) of 2.6 h at 4.5 mM, comparable with ivermectin [LC50 = 0.28 mM (247.4 μg/mL), LT50 = 8.9 h], an acaricidal drug standard. SAR analysis showed that the carbonyl group is crucial for the activity. The type and chain length of the alkoxy in the ester moiety and the steric hindrance near the ester group significantly influence the activity. The esters were more active than the corresponding thiol esters, amides, ketones or acids. Replacement of the phenyl group of cinnamic esters with α-pyridyl or α-furanyl significantly increase the activity. Thus, a series of cinnamic esters and its heteroaromatic ring analogues with excellent acaricidal activity emerged.
- Chen, Dong-Dong,Zhang, Bing-Yu,Liu, Xiu-Xiu,Li, Xing-Qiang,Yang, Xin-Juan,Zhou, Le
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p. 1149 - 1153
(2018/03/05)
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- Nitrile Hydration Reaction Using Copper Iodide/Cesium Carbonate/DBU in Nitromethane-Water
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The catalytic nitrile hydration (amide formation) in a copper iodide/cesium carbonate/1,8-diazabicyclo[5.4.0]undec-7-ene/nitromethane-water system is described. The protocol is robust and reliable; it can be applied to a broad range of substrates with high chemoselectivity.
- Kuwabara, Jun,Sawada, Yoshiharu,Yoshimatsu, Mitsuhiro
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supporting information
p. 2061 - 2065
(2018/09/14)
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- Selective and facile synthesis of α,β-unsaturated nitriles and amides with N-hydroxyphthalimide as the nitrogen source
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The direct conversion of α,β-unsaturated aldehydes to corresponding nitriles promoted by Pd(OAc)2 and phthalic acid which was hydrolyzed from N-hydroxyphthalimide (NHPI) has been disclosed. Additionally, it was found that when water was used as the solvent, α,β-unsaturated amides was obtained as the main products in good to excellent yields. It was first reported that NHPI was utilized as the nitrogen source to synthesize α,β-unsaturated nitriles and amides from aldehydes. Control experiment demonstrated that aldehydes undergo a process of oximation and dehydration to form nitriles and amides.
- Yan, Yiyan,Xu, Xiaohe,Jie, Xiaokang,Cheng, Jingya,Bai, Renren,Shuai, Qi,Xie, Yuanyuan
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p. 2793 - 2796
(2018/06/25)
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- Kryptofix 5 as an inexpensive and efficient ligand for the palladium-catalyzed Mizoroki-Heck reaction
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A novel complex of PdCl2 with a multidentate cryptand ligand, Kryptofix 5, has been prepared and characterized by various techniques including 1H- and 13C NMR spectroscopy, Fourier transform infrared (FT-IR), Raman, ultraviolet and visible (UV-VIS) spectroscopy, inductively coupled plasma (ICP), CHN elemental and energy dispersive X-ray analysis (EDX). This heat- and air-stable complex was utilized as a highly active catalyst for the Mizoroki-Heck reaction of aryl halides with various olefins. Interestingly, it was found that aryl bromides as well as aryl iodides were efficiently cross-coupled with terminal alkenes at 130?°C in 10?min. Furthermore, the least reactive aryl chlorides reacted with styrene to obtain the desired products in acceptable yields.
- Movassagh, Barahman,Ranjbari, Shabnam
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- Photocatalytic E → Z isomerization of polarized alkenes inspired by the visual cycle: Mechanistic dichotomy and origin of selectivity
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Iteratively executed with exquisite spatial and temporal control, the selective isomerization of polarized alkenes underpins a plethora of complex biological processes ranging from natural product biosynthesis through to the mammalian visual cycle. However, nature's proficiency conceals the inherent difficulties in replicating this contrathermodynamic transformation in the laboratory. Recently, we disclosed the first highly Z-selective isomerization of polarized alkenes, employing the cinnamoyl chromophore as a retinal surrogate under UV-irradiation (402 nm) with (-)-riboflavin (Vitamin B2) as an inexpensive, organic photocatalyst (J. Am. Chem. Soc. 2015, 137, 11254-11257). This study was inspired by the propensity of crystalline (-)-riboflavin in the eyes of vertebrates to invert the intrinsic directionality of retinal isomerization. Herein, we extend this methodology to include a bioinspired, catalytic E → Z isomerization of α,β-unsaturated nitriles, thereby mimicking the intermediate Opsin-derived, protonated Schiff base in the visual cycle with simple polarized alkenes. Replacement of the iminium motif by a cyano group is well tolerated and gives an additional degree of versatility for postisomerization functionalization. Broad substrate scope is demonstrated (up to 99:1 Z:E) together with evidence of mechanistic dichotomy via both singlet and triplet energy transfer mechanisms. Kinetic studies, temperature dependent photostationary state correlations and investigation of substituent-based electronic perturbation of the alkene identified polarization combined with increased Z-isomer activation barriers as the selectivity governing factors in catalysis. This investigation demonstrates the importance of internal structural preorganization on photostationary composition and explicates the augmented Z-selectivity upon hydrogen-alkyl exchange at the β-position of the alkene.
- Metternich, Jan B.,Artiukhin, Denis G.,Holland, Mareike C.,Von Bremen-Kuhne, Maximilian,Neugebauer, Johannes,Gilmour, Ryan
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p. 9955 - 9977
(2018/05/31)
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- Adenylation Activity of Carboxylic Acid Reductases Enables the Synthesis of Amides
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Carboxylic acid reductases (CARs) catalyze the reduction of a broad range of carboxylic acids to aldehydes using the cofactors adenosine triphosphate and nicotinamide adenine dinucleotide phosphate, and have become attractive biocatalysts for organic synthesis. Mechanistic understanding of CARs was used to expand reaction scope, generating biocatalysts for amide bond formation from carboxylic acid and amine. CARs demonstrated amidation activity for various acids and amines. Optimization of reaction conditions, with respect to pH and temperature, allowed for the synthesis of the anticonvulsant ilepcimide with up to 96 % conversion. Mechanistic studies using site-directed mutagenesis suggest that, following initial enzymatic adenylation of substrates, amidation of the carboxylic acid proceeds by direct reaction of the acyl adenylate with amine nucleophiles.
- Wood, Alexander J. L.,Weise, Nicholas J.,Frampton, Joseph D.,Dunstan, Mark S.,Hollas, Michael A.,Derrington, Sasha R.,Lloyd, Richard C.,Quaglia, Daniela,Parmeggiani, Fabio,Leys, David,Turner, Nicholas J.,Flitsch, Sabine L.
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supporting information
p. 14498 - 14501
(2017/10/18)
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- General and Efficient Intermolecular [2+2] Photodimerization of Chalcones and Cinnamic Acid Derivatives in Solution through Visible-Light Catalysis
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[2+2] Photocycloaddition, for example, the dimerization of chalcones and cinnamic acid derivatives, is a unique strategy to construct cyclobutanes, which are building blocks for a variety of biologically active molecules and natural products. However, most attempts at the above [2+2] addition have focused on solid-state, molten-state, or host–guest systems under ultraviolet-light irradiation in order to overcome the competition of facile geometric isomerization of nonrigid olefins. We report a general and simple method to realize the intermolecular [2+2] dimerization reaction of these acyclic olefins to construct cyclobutanes in a highly regio- and diastereoselective manner in solution under visible light, which provides an efficient solution to a long-standing problem.
- Lei, Tao,Zhou, Chao,Huang, Mao-Yong,Zhao, Lei-Min,Yang, Bing,Ye, Chen,Xiao, Hongyan,Meng, Qing-Yuan,Ramamurthy, Vaidhyanathan,Tung, Chen-Ho,Wu, Li-Zhu
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p. 15407 - 15410
(2017/11/13)
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- Phosphinous Acid-Assisted Hydration of Nitriles: Understanding the Controversial Reactivity of Osmium and Ruthenium Catalysts
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The synthesis and catalytic behavior of the osmium(II) complexes [OsCl2(η6-p-cymene)(PR2OH)] [R=Me (2 a), Ph (2 b), OMe (2 c), OPh (2 d)] in nitrile hydration reactions is presented. Among them, the best catalytic results were obtained with the phosphinous acid derivative [OsCl2(η6-p-cymene)(PMe2OH)] (2 a), which selectively provided the desired primary amides in excellent yields and short times at 80 °C, employing directly water as solvent, and without the assistance of any basic additive (TOF values up to 200 h?1). The process was successful with aromatic, heteroaromatic, aliphatic, and α,β-unsaturated organonitriles, and showed a high functional group tolerance. Indeed, complex 2 a represents the most active and versatile osmium-based catalyst for the hydration of nitriles reported so far in the literature. In addition, it exhibits a catalytic performance similar to that of its ruthenium analogue [RuCl2(η6-p-cymene)(PMe2OH)] (4). However, when compared to 4, the osmium complex 2 a turned out to be faster in the hydration of less-reactive aliphatic nitriles, whereas the opposite trend was generally observed with aromatic substrates. DFT calculations suggest that these differences in reactivity are mainly related to the ring strain associated with the key intermediate in the catalytic cycle, that is, a five-membered metallacyclic species generated by intramolecular addition of the hydroxyl group of the phosphinous acid ligand to the metal-coordinated nitrile.
- González-Fernández, Rebeca,Crochet, Pascale,Cadierno, Victorio,Menéndez, M. Isabel,López, Ramón
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p. 15210 - 15221
(2017/10/12)
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- Hemilability-Driven Water Activation: A NiII Catalyst for Base-Free Hydration of Nitriles to Amides
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The NiII complex 1 containing pyridyl- and hydroxy-functionalized N-heterocyclic carbenes (NHCs) is synthesized and its catalytic utility for the selective nitrile hydration to the corresponding amide under base-free conditions is evaluated. The title compound exploits a hemilabile pyridyl unit to interact with a catalytically relevant water molecule through hydrogen-bonding and promotes a nucleophilic water attack to the nitrile. A wide variety of nitriles is hydrated to the corresponding amides including the pharmaceutical drugs rufinamide, Rifater, and piracetam. Synthetically challenging α-hydroxyamides are accessed from cyanohydrins under neutral conditions. Related catalysts that lack the pyridyl unit (i.e., compounds 2 and 4) are not active whereas those containing both the pyridyl and the hydroxy or only the pyridyl pendant (i.e., compounds 1 and 3) show substantial activity. The linkage isomer 1′ where the hydroxy group is bound to the metal instead of the pyridyl group was isolated under different crystallization conditions insinuating a ligand hemilabile behavior. Additional pKa measurements reveal an accessible pyridyl unit under the catalytic conditions. Kinetic studies support a ligand-promoted nucleophilic water addition to a metal-bound nitrile group. This work reports a Ni-based catalyst that exhibits functional hemilability for hydration chemistry.
- Singh, Kuldeep,Sarbajna, Abir,Dutta, Indranil,Pandey, Pragati,Bera, Jitendra K.
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p. 7761 - 7771
(2017/06/06)
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- Direct Catalytic Desaturation of Lactams Enabled by Soft Enolization
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A direct catalytic method is described for the α,β-desaturation of N-protected lactams to their conjugated unsaturated counterparts under mildly acidic conditions. The reaction is consistently operated at room temperature and tolerates a wide range of functional groups, showing reactivity complementary to that of prior desaturation methods. Lactams with various ring sizes and substituents at different positions all reacted smoothly. The synthetic utility of this method is demonstrated in a concise synthesis of Rolipram. In addition, linear amides also prove to be competent substrates, and the phthaloyl-protected product serves as a convenient precursor to access various conjugated carboxylic acid derivatives. Strong bases are avoided in this desaturation approach, and the key is to merge soft enolization with a Pd-catalyzed oxidation process.
- Chen, Ming,Dong, Guangbin
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p. 7757 - 7760
(2017/06/21)
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- Pd0.09Ce0.91O2-Δ: A sustainable ionic solid-solution precatalyst for heterogeneous, ligand free Heck coupling reactions
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A quick and easy method for the preparation of Pd2+ metal ion substituted in ceria, Pd0.09Ce0.91O2-δ solid solution oxide, is described. The Pd0.09Ce0.91O2-δ solid solution oxide was fully characterized by XRD, ICP-OES, BET, XPS, SEM, EDX, TEM, TGA and Raman spectroscopy. All characterization techniques strongly suggested that Pd2+ was successfully incorporated into the lattice structure of ceria. The effect of the reaction conditions on the catalytic properties of the Pd0.09Ce0.91O2-δ solid solution catalyst initially was studied in detail with the model Heck reaction of iodobenzene and methylacrylate to obtain optimum reaction conditions. The Pd0.09Ce0.91O2-δ solid solution catalyst then afforded substituted alkenes in good to excellent yields under these optimum reaction conditions. Steric and electronic effects were also studied, and were found to influence the catalytic activity. Characterization of the used catalyst suggests that Pd2+ in Pd0.09Ce0.91O2-δ is reduced in situ to Pd0 when employed in the Heck cross-coupling reactions. The catalyst was easily recovered by centrifuge and reused three times without significant loss of catalytic efficiency.
- Mpungose, Philani P.,Sehloko, Neo I.,Dasireddy, Venkata D.B.C.,Mahadevaiah, Narayanappa,Maguire, Glenn E.,Friedrich, Holger B.
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- Synthesis and catalytic applications of ruthenium(ii)-phosphino-oxime complexes
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In this work, the preparation of the first ruthenium complexes containing a phosphino-oxime ligand is presented. Thus, the reaction of cis-[RuCl2(DMSO)4] (3) with 2.4 equivalents of 2-Ph2PC6H4CH=NOH (1) in refluxing THF led to the clean formation of the octahedral ruthenium(ii) derivative cis,cis,trans-[RuCl2{κ2-(P,N)-2-Ph2PC6H4CH=NOH}2] (5), whose structure was unambiguously confirmed by means of a single-crystal X-ray diffraction study. Complex 5 could also be synthesized from the reaction of the dimer [{RuCl(μ-Cl)(η6-p-cymene)}2] (4) with an excess of 1 in refluxing toluene. Treatment of 4 with 2 equivalents of 1, in CH2Cl2 at r.t., allowed also the preparation of the half-sandwich Ru(ii) derivative [RuCl{κ2-(P,N)-2-Ph2PC6H4CH=NOH}(η6-p-cymene)][PF6] (6). In addition, complexes 5 and 6 proved to be active catalysts for the rearrangement of aldoximes to primary amides, as well as for the α-alkylation/reduction of acetophenones with primary alcohols, with the former showing the best performances in both processes.
- Francos, Javier,Menéndez-Rodríguez, Lucía,Tomás-Mendivil, Eder,Crochet, Pascale,Cadierno, Victorio
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p. 39044 - 39052
(2016/06/01)
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- Synthesis and biological evaluation of (E)-cinnamic acid, (E)-2-styrylthiazole and (E)-2-[2-(naphthalen-1-yl)vinyl]thiazole derivatives
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Cinnamyl- and thiazole-based compounds have been shown to exhibit diverse medicinal properties and a series of twelve (E)-2-styrylthiazole and (E)-2-[(naphthalen-1-yl)vinyl]thiazole derivatives, which are conjugates of both systems and which satisfy the “Lipinski rule of 5”, have been synthesised and subjected to in vitro biological screening. While insignificant inhibition (60-98% viability at 10 μM) of HeLa (cervical cancer) cells was noted, all five of the (E)-2-[naphthalen-1-yl)vinyl]thiazole derivatives proved remarkably active against SH-SY5Y (neuroblastoma) cells with IC50 values ranging from 2.09 to 8.64 μM. Two of the seven (E)-2-styrylthiazoles were found to be moderately active (with IC50 values of 10.8 and 11.7 mM), whereas the remaining five analogues exhibit significant proliferation of SH-SY5Y cells (with IC50 values of 180-1000 mM). The results warrant further studies on the effects of styrylthiazoles on the differentiation and extension of SH-SY5Y cells in order to assess their activity in neurological degenerative diseases.
- Olawode, Emmanuel O.,Tandlich, Roman,Prinsloo, Earl,Isaacs, Michelle,Hoppe, Heinrich,Seldon, Ronnett,Warner, Digby F.,Steenkamp, Vanessa,Kaye, Perry T.
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p. 284 - 296
(2018/05/09)
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- Synthesis and biological evaluation of (E)-cinnamic acid, (E)-2-styrylthiazole and (E)-2-[2-(naphthalen-1-yl)vinyl]thiazole derivatives
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Cinnamyl- and thiazole-based compounds have been shown to exhibit diverse medicinal properties and a series of twelve (E)-2-styrylthiazole and (E)-2-[(naphthalen-1-yl)vinyl]thiazole derivatives, which are conjugates of both systems and which satisfy the "Lipinski rule of 5", have been synthesised and subjected to in vitro biological screening. While insignificant inhibition (60-98% viability at 10 μM) of HeLa (cervical cancer) cells was noted, all five of the (E)-2-[naphthalen-1- yl)vinyl]thiazole derivatives proved remarkably active against SH-SY5Y (neuroblastoma) cells with IC50 values ranging from 2.09 to 8.64 μM. Two of the seven (E)-2-styrylthiazoles were found to be moderately active (with IC50 values of 10.8 and 11.7 mM), whereas the remaining five analogues exhibit significant proliferation of SH-SY5Y cells (with IC50 values of 180-1000 mM). The results warrant further studies on the effects of styrylthiazoles on the differentiation and extension of SH-SY5Y cells in order to assess their activity in neurological degenerative diseases.
- Olawode, Emmanuel O.,Tandlich, Roman,Prinsloo, Earl,Isaacs, Michelle,Hoppe, Heinrich,Seldon, Ronnett,Warner, Digby F.,Steenkamp, Vanessa,Kaye, Perry T.
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p. 284 - 296
(2018/03/09)
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- Chlorophosphines as auxiliary ligands in ruthenium-catalyzed nitrile hydration reactions: Application to the preparation of β-ketoamides
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The catalytic hydration of nitriles into amides, in water under neutral conditions, has been studied using a series of arene-ruthenium(ii) complexes containing commercially available chlorophosphines as auxiliary ligands, i.e. compounds [RuCl2(η6-p-cymene)(PR2Cl)] (R = aryl, heteroaryl or alkyl group). In the reaction medium, the coordinated chlorophosphines readily undergo hydrolysis to generate the corresponding phosphinous acids PR2OH, which are well-known "cooperative" ligands for this catalytic transformation. Among the complexes employed, best results were obtained with [RuCl2(η6-p-cymene){P(4-C6H4F)2Cl}]. Performing the catalytic reactions at 40 °C with 2 mol% of this complex, a large variety of organonitriles could be selectively converted into the corresponding primary amides in high yields and relatively short times. The application of [RuCl2(η6-p-cymene){P(4-C6H4F)2Cl}] in the preparation of synthetically useful β-ketoamides is also presented.
- González-Fernández, Rebeca,González-Liste, Pedro J.,Borge, Javier,Crochet, Pascale,Cadierno, Victorio
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p. 4398 - 4409
(2016/07/06)
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- Poly(amic acid) salt-stabilized silver nanoparticles as efficient and recyclable quasi-homogeneous catalysts for the aqueous hydration of nitriles to amides
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Water-soluble silver nanoparticles stabilized by poly(amic acid) salt (Ag-PAAS) were synthesized by a one-pot method and were characterized by using UV-vis absorption, transmission electron microscopy, powder X-ray diffraction, and ζ potential measurements. The Ag-PAAS catalyzed selective hydration of nitriles to amides in water allowed for not only highly efficient quasi-homogeneous catalytic reactions under mild conditions, but also an easy recovery and reuse of the catalyst attributed to the pH response of the PAAS.
- Li, Jun,Tang, Guannan,Wang, Yuchen,Wang, Ya,Li, Zixi,Li, Hengfeng
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p. 358 - 364
(2016/01/12)
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- Clean synthesis of primary to tertiary carboxamides by CsOH-catalyzed aminolysis of nitriles in water
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Using CsOH as the only catalyst and utilizing its "cesium effect", a clean synthesis of a wide range of primary, secondary, and tertiary carboxamides was achieved by aminolysis reactions of nitriles with ammonia, primary, or secondary amines in water. Studies on the control reactions revealed that the reactions with ammonia most probably proceed via an aminolysis path by the initial addition of ammonia to Cs-activated nitriles to form unsubstituted amidine intermediates, while the reactions with primary or secondary amines may proceed via a hydration/transamidation path by the initial hydration of the Cs-activated nitriles to form primary carboxamide intermediates followed by their transamidation with amines through the formation of substituted amidine intermediates.
- Li, Yang,Chen, Haonan,Liu, Jianping,Wan, Xujun,Xu, Qing
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supporting information
p. 4865 - 4870
(2016/10/06)
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- Supported Gold Nanoparticles-Catalyzed Microwave-Assisted Hydration of Nitriles to Amides under Base-Free Conditions
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Polystyrene-supported gold (Au@PS) nanoparticles were synthesized by the reduction deposition approach and well characterized by UV-visible, XRD, TEM, SAED, EDX, and XPS studies. The Au@PS was applied as catalyst for the hydration of nitriles to amides in water under microwave irradiation. Several functionalized aromatic, heterocyclic and aliphatic nitriles were found to be active for synthesis of the corresponding amides where no activation of water by base, ligand and support is needed. Easy recovery, negligible leaching and recyclability for up to eight runs are added advantages of the catalyst under water-mediated reaction conditions. (Figure presented.).
- Kumar, Sandeep,Sharma, Saurabh,Das, Pralay
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supporting information
p. 2889 - 2894
(2016/09/16)
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- A method from the aldehyde amide
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The invention discloses a method for synthesizing amides from aldehyde. The method comprises the following steps: adding aldehyde, hydroxylamine hydrochloride, alkali and water to a reaction vessel to react at room temperature for half an hour; adding a water-soluble iridium complex after aldehyde is completely transformed into oxime, cooling a reactant to the room temperature after the reaction mixture reacts at 80-120 DEG C for several hours, removing water through selective evaporation, and obtaining a target product through column separation. Compared with existing methods for synthesizing amides by generating oxime through one-pot reaction between aldehyde and hydroxylamine in water and then carrying out rearrangement, the method has the advantages that the used catalyst is low in load and does not contain phosphine ligands severely polluting the environment, so that the reaction can be carried out in the air, without nitrogen protection; therefore the reaction meets the green chemical requirements and has an extensive development prospect.
- -
-
Paragraph 0060; 0061; 0062; 0063
(2017/04/08)
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- Highly efficient and recyclable copper based ionic liquid catalysts for amide synthesis
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A series of Cu based ionic liquids was synthesized by the reaction of 1-butyl-3-methylimidazolium salts and copper(ii) salts. These ionic liquids were investigated as catalysts in the synthesis of amides (primary, secondary and tertiary amides). For easy separation and recycling, the Cu based ionic liquids were decorated on nanocrystalline silicalite. The materials were characterized using powder X-ray diffraction, nitrogen adsorption, scanning and transmission electron microscopy, thermogravimetric analysis, and nuclear magnetic resonance, Fourier transform infrared and UV-visible spectroscopy. The Cu based ionic liquids decorated on nanocrystalline silicalite were found to be efficient and recyclable catalysts for the amide synthesis. The catalysts were found to be stable and show negligible loss of the activity even after five cycles.
- Rani, Poonam,Srivastava, Rajendra
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p. 7162 - 7170
(2016/08/09)
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- Iron-facilitated oxidative radical decarboxylative cross-coupling between α-oxocarboxylic acids and acrylic acids: An approach to α,β-unsaturated carbonyls
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The first Fe-facilitated decarboxylative cross-coupling reaction between α-oxocarboxylic acids and acrylic acids in aqueous solution has been developed. This transformation is characterized by its wide substrate scope and good functional group compatibility utilizing inexpensive and easily accessible reagents, thus providing an efficient and expeditious approach to an important class of α,β-unsaturated carbonyls frequently found in bioactive compounds. The synthetic potential of the coupled products is also demonstrated in subsequent functionalization reactions. Preliminary mechanism studies suggest that a free radical pathway is involved in this process: the generation of an acyl radical from α-oxocarboxylic acid via the excision of carbon dioxide followed by the addition of an acyl radical to the α-position of the double bond in acrylic acid then delivers the α,β-unsaturated carbonyl adduct through the extrusion of another carbon dioxide.
- Jiang, Qing,Jia, Jing,Xu, Bin,Zhao, An,Guo, Can-Cheng
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p. 3586 - 3596
(2015/04/22)
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- Palladium(II) complexes with a phosphino-oxime ligand: Synthesis, structure and applications to the catalytic rearrangement and dehydration of aldoximes
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The treatment of [PdCl2(COD)] (COD = 1,5-cyclooctadiene) with 1 and 2 equivalents of 2-(diphenylphosphino)benzaldehyde oxime in dichloromethane at room temperature led to the selective formation of [PdCl2{κ2-(P,N)-2-Ph2PC6H4CHNOH}] (1) and [Pd{κ2-(P,N)-2-Ph2PC6H4CHNOH}2][Cl]2 (2), respectively, which represent the first examples of Pd(II) complexes containing a phosphino-oxime ligand. These compounds, whose structures were fully confirmed by X-ray diffraction methods, were active in the catalytic rearrangement of aldoximes. In particular, using 5 mol% complex 1, a large variety of aldoximes could be cleanly converted into the corresponding primary amides at 100 °C, employing water as solvent and without the assistance of any cocatalyst. Palladium nanoparticles are the active species in the rearrangement process. In addition, when the same reactions were performed employing acetonitrile as solvent, selective dehydration of the aldoximes to form the respective nitriles was observed. For comparative purposes, the catalytic behaviour of an oxime-derived palladacyclic complex has also been briefly evaluated.
- Menéndez-Rodríguez, Lucía,Tomás-Mendivil, Eder,Francos, Javier,Nájera, Carmen,Crochet, Pascale,Cadierno, Victorio
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p. 3754 - 3761
(2015/07/01)
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- A magnetic porous chitosan-based palladium catalyst: A green, highly efficient and reusable catalyst for Mizoroki-Heck reaction in aqueous media
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A novel, biodegradable and environmentally benign magnetic porous chitosan-thienyl imine palladium(ii) complex, MPCS-TI/Pd, was prepared and characterized by FT-IR, SEM, TEM, EDX, XRD, BET, VSM and TG-DTA analysis. This complex, with high surface areas and low catalyst loading, was found to be a highly active and robust heterogeneous catalyst for the Mizoroki-Heck reaction of aryl bromides and chlorides with various terminal olefins in aqueous media in good to excellent yields. The catalyst was easily separated using an external magnet and the recovered catalyst was reused for seven cycles without significant loss of catalytic activity.
- Movassagh, Barahman,Rezaei, Nasrin
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supporting information
p. 7988 - 7997
(2015/10/12)
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- Rearrangement of aldoximes to amides in water under air atmosphere catalyzed by water-soluble iridium complex [Cp*Ir(H2O) 3][OTf]2
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In the presence of the water-soluble iridium complex [Cp*Ir(H 2O)3][OTf]2, a variety of aldoximes, including aromatic, aliphatic, conjugated unsaturated and non-conjugated unsaturated, were converted into their corresponding amides in water with good to excellent yields. Further, the one-pot synthesis of amides from aldehydes, hydroxylamine hydrochloride and sodium carbonate via a tandem condensation-rearrangement reaction in water was also accomplished. Compared with the reported organometallic catalysts for the rearrangement of aldoximes to amides in water, the present catalyst exhibited some advantages such as being phosphorus ligand-free, having low catalyst loading, and operational convenience under air atmosphere. This journal is the Partner Organisations 2014.
- Sun, Chunlou,Qu, Panpan,Li, Feng
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p. 988 - 996
(2014/04/03)
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- Investigation of binap-based hydroxyphosphine arene-ruthenium(II) complexes as catalysts for nitrile hydration
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The binap-based hydroxyphosphine-(η6-arene)-ruthenium(ii) complexes [RuX{η6:κ1(P)-PPh2-binaphthyl}{PPh2(OH)}][OTf] (X = OTf (4), Cl (5)) have been evaluated as potential catalysts for the selective hydration of nitriles to primary amides. The triflate derivative 4 proved to be the most active, being able to hydrate a large variety of aromatic, heteroaromatic, α,β-unsaturated and aliphatic nitriles in pure water at 100°C. The utility of complex 4 to promote the catalytic rearrangement of aldoximes has also been demonstrated. In addition, insights about the role played by the hydroxyphosphine ligand PPh2(OH) during the catalytic reactions are given.
- Toms-Mendivil, Eder,Menndez-Rodrguez, Luca,Francos, Javier,Crochet, Pascale,Cadierno, Victorio
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p. 63466 - 63474
(2015/02/19)
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- Bronsted acid mediated nitrogenation of propargylic alcohols: An efficient approach to alkenyl nitriles
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A novel and efficient approach to alkenyl nitriles from readily available propargylic alcohols has been developed. This nitrogenation reaction is transition-metal-free and could be conducted under air at ambient temperature, which makes this protocol promising and practical. Moreover, NH4Br is disclosed as an efficient additive to promote the stereoselectivity of this reaction. the Partner Organisations 2014.
- Huang, Xiaoqiang,Jiao, Ning
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supporting information
p. 4324 - 4328
(2014/06/23)
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- Efficient and selective nitrile hydration reactions in water catalyzed by an unexpected dimethylsulfinyl anion generated in situ from CsOH and DMSO
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Unexpected dimethylsulfinyl anions (I), generated in situ from the superbase system CsOH-DMSO, was found to be a highly active catalyst for controllable nitrile hydration reactions in water, which selectively afforded the versatile amides via interesting Cs-activated I-catalyzed direct and indirect hydration mechanisms involving an O-transfer process from DMSO onto the nitriles. the Partner Organisations 2014.
- Chen, Haonan,Dai, Wujie,Chen, Yi,Xu, Qing,Chen, Jianhui,Yu, Lei,Zhao, Yajuan,Ye, Mingde,Pan, Yuanjiang
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supporting information
p. 2136 - 2141
(2014/04/17)
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- Thiazolyl-phosphine hydrochloride salts: Effective auxiliary ligands for ruthenium-catalyzed nitrile hydration reactions and related amide bond forming processes in water
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A series of water-soluble N-protonated thiazolyl-phosphine hydrochloride salts have been synthesized and coordinated to the ruthenium(ii) fragment [RuCl2(η6-p-cymene)]. The resulting complexes were evaluated as potential catalysts for the selective hydration of nitriles to primary amides in environmentally friendly aqueous medium. The best results in terms of activity were achieved when tris(5-(2-aminothiazolyl))phosphine trihydrochloride was used as ligand. Using the Ru(ii) complex 9 derived from this salt (3 mol%), the catalytic reactions proceeded cleanly in pure water at 100 °C without the assistance of any additive, affording the desired amides in high yields (>78%) after short reaction periods (0.5-7 h). The process was operative with both aromatic, heteroaromatic, α,β-unsaturated and aliphatic nitriles, and tolerated several functional groups. The utility of 9 in promoting the formation of primary amides in water by catalytic rearrangement of aldoximes and direct coupling of aldehydes with NH2OH·HCl has also been demonstrated.
- Garcia-Alvarez, Rocio,Zablocka, Maria,Crochet, Pascale,Duhayon, Carine,Majoral, Jean-Pierre,Cadierno, Victorio
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p. 2447 - 2456
(2013/09/12)
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- Convenient synthesis of various substituted homotaurines from alk-2-enamides
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Various substituted homotaurines (=3-aminopropane-1-sulfonic acids) 6 were readily synthesized in satisfactory to good yields via the Michael addition of thioacetic acid to alk-2-enamides 3 (→4), followed by LiAlH4 reduction (→5) and performic acid oxidation (Scheme 1). The configuration of 'anti'-disubstituted homotaurine 'anti'-6h was deduced from the 3-(acetylthio)alkanamide (=S-(3-amino-1,2-dimethyl-3-oxopropyl) ethanethioate)'anti'-4h formed in the Michael addition, which was identified via the Karplus equation analysis, and confirmed by X-ray diffraction analysis. The current route is an efficient method to synthesize diverse substituted homotaurines, including 1-, 2-, and N-monosubstituted, as well as 1,2-, 1,N-, 2,N-, and N,N-disubstituted homotaurines (Table). Copyright
- Nai, Youfeng,Xu, Jiaxi
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p. 1355 - 1365
(2013/08/23)
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- Solid-supported ruthenium(0): An efficient heterogeneous catalyst for hydration of nitriles to amides under microwave irradiation
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Solid-supported ruthenium(0) was synthesized by the reduction deposition method and used as a heterogeneous catalyst for the hydration of nitriles to amides under microwave irradiation. A wide range of aromatic, α,β-unsaturated and aliphatic nitriles were efficiently converted to their corresponding primary amides under milder conditions. The catalyst was found to be very stable under moisture and microwave irradiation, easily separable from the reaction mixture, to cause negligible metal contamination of the product and was recyclable up to ten times without significant loss of catalytic activity.
- Kumar, Sandeep,Das, Pralay
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supporting information
p. 2987 - 2990
(2013/10/01)
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- Ruthenium-catalyzed one-pot synthesis of primary amides from aldehydes in water
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The readily available arene-ruthenium(ii) complex [RuCl2(η 6-C6Me6){P(NMe2)3}] (5 mol%) proved to be an efficient catalyst for the direct synthesis of primary amides from aldehydes and hydroxylamine hydrochloride (NH2OH· HCl) in water at 100 °C. The process, which requires the presence of NaHCO3 to catch the HCl released during the formation of the key aldoxime intermediates, was operative with both aromatic, heteroaromatic, α,β-unsaturated and aliphatic aldehydes, and tolerated several functional groups. A greener approach using commercially available NH 2OH solution (50 wt.% in water) is also presented.
- Garcia-Alvarez, Rocio,Diaz-Alvarez, Alba E.,Crochet, Pascale,Cadierno, Victorio
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p. 5889 - 5894
(2013/05/09)
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- Palladium chloride catalyzed photochemical Heck reaction
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PdCl2 catalyzed carbon-carbon bond formation (Heck reaction) between substituted aryl halides and olefins was carried out without a ligand, under irradiation with UV-visible light. The results demonstrated that UV-visible light accelerated the rate of the reaction, leading to an excellent yield of corresponding products. The recovered palladium nanoparticles could be thermally recycled several times. PdCl2 gave excellent conversion up to the fifth addition of substrate.
- Waghmode, Suresh B.,Arbuj, Sudhir S.,Wani, Bina N.,Gopinath
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supporting information
p. 348 - 351
(2013/06/04)
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