- Asymmetric Reduction of Electron-Rich Ketones with Tethered Ru(II)/TsDPEN Catalysts Using Formic Acid/Triethylamine or Aqueous Sodium Formate
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The asymmetric transfer hydrogenation (ATH) of ketones under aqueous conditions using tethered Ru(II)/6-arene/diamine catalysts is described, as is the ATH of electron-rich substrates containing amine and methoxy groups on the aromatic rings. Although such substrates are traditionally challenging ones for ATH, the tethered catalysts work very efficiently. In the case of amino-substituted ketones, aqueous conditions give excellent results; however, for methoxy-substituted substrates, the more established formic acid/triethylamine system gives superior results.
- Soni, Rina,Hall, Thomas H.,Mitchell, Benjamin P.,Owen, Matthew R.,Wills, Martin
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Read Online
- High-Throughput Experimentation and Continuous Flow Evaluation of Nucleophilic Aromatic Substitution Reactions
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Nucleophilic aromatic substitution (SNAr) reactions were optimized using high-throughput experimentation techniques for execution under flow conditions. A total of 3072 unique reactions were evaluated with an analysis time of ~3.5 s per reaction using a system that combines a liquid handling robot for reaction mixture preparation with desorption electrospray ionization (DESI) mass spectrometry (MS) for analysis. The reactions were performed in bulk microtiter arrays with and without incubation. In-house developed software was used to process the data and generate heat maps of the results. This information was then used to select the most promising conditions for continuous synthesis under microfluidic reactor conditions. Our results show that this HTE approach provides robust guidance for narrowing the range of conditions needed for optimization of SNAr reactions.
- Aremu, Deborah,Avramova, Larisa,Cooks, R. Graham,Jaman, Zinia,Logsdon, David L.,Sobreira, Tiago J. P.,Szilágyi, Botond,Thompson, David H.
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Read Online
- Palladium-catalyzed selective amination of haloaromatics on KF-alumina surface
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An efficient palladium-catalyzed amination, including polyaminations of aromatic bromides mediated on a surface of KF-alumina, is reported. The solvent-free one-pot protocol avoids the use of a strong base (sodium tert-butoxide) making it applicable to substrates containing a base-sensitive functional group. It proceeds without concomitant reductive bromination and provides access to selective amination of polyhaloaromatics.
- Basu, Basudeb,Das, Pralay,Nanda, Ashish K.,Das, Sajal,Sarkar, Sajal
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Read Online
- A novel and unusual method for C[sbnd]N bond formation between benzene ring and various amines
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A new approach to form C[sbnd]N bond without metal catalysis was developed. 4-acetylbenzoyl isocyanate reacted with various amines through a mild method to form C[sbnd]N bond. This reaction was amenable to scale-up and it afforded the corresponding products with good to excellent yields and tolerates a wide range of functional groups.
- Wang, Peng,Wang, Chen,Zhu, Zhenzhen,Xu, Sicong,Hou, Yunlei,Zhao, Yanfang
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- Design, Synthesis and Antitubercular Activity of Novel Isoniazid?Cyclic?Amine?Azachalcones Hybrids
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In this work, it is described the design of twenty-four heterocyclic amine-azachalcones compounds through molecular hybridization of chalcone scaffold and fragments of isoniazid, fluoroquinolones, and linezolid with antituberculosis potential. The new compounds were synthesized via Claisen-Schmidt condensation, providing yields of 36-95%. Fifteen compounds showed antituberculosis activity against Mycobacterium tuberculosis H37Rv strain. Two amine-azachalcones 15 and 17 showed relevant biological activity with minimum inhibitory concentration (MIC) values of 6.62 and 4.85 μM, respectively. Compound 12 showed the best profile of antitubercular activity with MIC = 9.54 μM and selectivity index (SI) = 9.33. It was found that morpholine group is important to increase potency of antimycobacterial activity but also to add some toxicity to the chalcone molecular framework. The results described herein would be a guide in the designing of novel and optimized antitubercular derivatives based on the chalcone scaffold.
- Barbosa, Sandro L.,Baroni, Adriano C. M.,Croda, Júlio,Gomes, Giovana B.,Guerrero, Palimécio G.,Moreira, Flora M. F.,Oliveira, Jefferson R. S.,Perdomo, Renata T.,Shiguemoto, Cristiane Y. K.,das Neves, Amarith R.
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p. 1284 - 1295
(2020/10/14)
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- General Paradigm in Photoredox Nickel-Catalyzed Cross-Coupling Allows for Light-Free Access to Reactivity
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Self-sustained NiI/III cycles are established as a potentially general paradigm in photoredox Ni-catalyzed carbon–heteroatom cross-coupling reactions through a strategy that allows us to recapitulate photoredox-like reactivity in the absence of light across a wide range of substrates in the amination, etherification, and esterification of aryl bromides, the latter of which has remained, hitherto, elusive under thermal Ni catalysis. Moreover, the accessibility of esterification in the absence of light is especially notable because previous mechanistic studies on this transformation under photoredox conditions have unanimously invoked energy-transfer-mediated pathways.
- Nocera, Daniel G.,Qin, Yangzhong,Sun, Rui
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supporting information
p. 9527 - 9533
(2020/04/08)
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- COMPOUNDS AND METHODS OF THEIR USE
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Provided are agents capable of binding the KIX domain of CBP or MED15 to inhibit the binding between SREBP1 and the KIX domain of MED15 or CBP. Also provided are compositions containing the agents and methods of their use.
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Page/Page column 85
(2020/05/19)
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- A group of diphosphine-thiosemicarbazone complexes of palladium: Efficient precursors for catalytic C–C and C–N coupling reactions
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Reaction of 4-R-benzaldehyde thiosemicarbazone (denoted in general as HL-R; where H stands for the dissociable acidic proton and R (R = OCH3, CH3, H, Cl and NO2) for the substituent) with [Pd(dppe)(EtOH)2]2+, generated in situ via interaction of [Pd(dppe)Cl2] (dppe = 1,2-bis(diphenylphosphino)ethane) with AgNO3 in hot ethanol, in the presence of triethylamine affords a group of orange complexes of the type [Pd(dppe)(L-R)]NO3. Structures of [Pd(dppe)Cl2] and [Pd(dppe)(L-OCH3)]NO3 have been determined by X-ray crystallography. In the [Pd(dppe)(L-R)]NO3 complexes, the thiosemicarbazone ligands are coordinated to the metal center as monoanionic bidentate N,S-donors forming five-membered chelate rings. The [Pd(dppe)(L-R)]NO3 complexes show intense absorptions in the visible and ultraviolet regions, which have been analyzed by TDDFT calculations. All the [Pd(dppe)(L-R)]NO3 complexes are found to efficiently catalyze Suzuki-type C–C and Buchwald-type C–N coupling reactions.
- Thapa, Kiran,Paul, Piyali,Bhattacharya, Samaresh
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p. 232 - 239
(2018/11/06)
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- Piperidine ring containing chalcone compound as well as preparation and application of piperidine ring containing chalcone compound
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The invention provides a piperidine ring containing chalcone compound. The piperidine ring containing chalcone compound is prepared by mixing fluoroacetophenone and piperidine, heating, refluxing, then mixing with an aromatic aldehyde compound, and heating and refluxing to react in a solvent under the alkaline action. The preparation condition is mild, the operation is convenient, the cost is low,and the industrial application prospect is broad. The provided piperidine ring containing chalcone compound shows better anti-breast cancer activity, lays a foundation for the screening and developing of new drugs, has an important practical value, and can be applied to preparing drugs for treating breast cancer; the structural general formula is shown in the description.
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Paragraph 0009; 0018-0021
(2019/07/04)
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- Application of hydrazino and hydrazido linkers to connect benzenesulfonamides with hydrophilic/phobic tails for targeting the middle region of human carbonic anhydrases active site: Selective inhibitors of hCA IX
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Herein we report the design and synthesis of three different sets of novel benzenesulfonamides (5a-e, 7a-e and 10a-d) incorporating hydrophilic/hydrophobic tails by hydrazido or hydrazino linkers. The newly synthesized benzenesulfonamides were examined in vitro for their inhibitory activity towards four human (h) carbonic anhydrase (hCA, EC 4.2.1.1) isoforms, hCA I, II, IX and XII using a stopped-flow CO2 hydrase assay. All these isoforms were inhibited by the sulfonamides (5a-e, 7a-e and 10a-d) with variable degrees in the following KI ranges: 76.8–357.4 nM for hCA I, 8.2–94.6 nM for hCA II, 2.0–46.3 nM for hCA XI, and 8.3–88.3 nM for hCA XII. The sulfonamide 7d exhibited potent anti-proliferative activity against breast MCF-7 cancer cell line under both normoxic and hypoxic conditions with IC50 values equal 3.32 ± 0.06 and 8.53 ± 0.32 μM, respectively, which are comparable to the reference drug doxorubicin (IC50 = 2.36 ± 0.04 and 8.39 ± 0.25 μM, respectively). Furthermore, 7d was screened for cell cycle disturbance and apoptosis induction in MCF-7 cells. It was found to persuade cell cycle arrest at G2-M stage as well as to alter the Sub-G1 phase, also, 7d resulted in a significant increase in the percent of annexinV-FITC positive apoptotic cells from 1.03 to 18.54%. Molecular docking study was carried out for 7d within the hCA IX and hCA XII active sites to rationalize the obtained inhibition results.
- Allam, Heba Abdelrasheed,Fahim, Samar H.,F.Abo-Ashour, Mahmoud,Nocentini, Alessio,Elbakry, Mohamed E.,Abdelrahman, Mohamed A.,Eldehna, Wagdy M.,Ibrahim, Hany S.,Supuran, Claudiu T.
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p. 547 - 556
(2019/07/04)
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- Exploring Tandem Ruthenium-Catalyzed Hydrogen Transfer and SNAr Chemistry
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A hydrogen-transfer strategy for the catalytic functionalization of benzylic alcohols via electronic arene activation, accessing a diverse range of bespoke diaryl ethers and aryl amines in excellent isolated yields (38 examples, 70% average yield), is reported. Taking advantage of the hydrogen-transfer approach, the oxidation level of the functionalized products can be selected by judicious choice of simple and inexpensive additives.
- Polidano, Kurt,Reed-Berendt, Benjamin G.,Basset, Ana?s,Watson, Andrew J. A.,Williams, Jonathan M. J.,Morrill, Louis C.
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p. 6716 - 6719
(2017/12/26)
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- An efficient heterogeneous ligand free C-N coupling reaction catalyzed by palladium supported on magnetic nanoparticles
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The catalytic activity of palladium supported on magnetic nanoparticles in the amination coupling reaction of different nitrogen containing substrates with aryl halides was investigated. C-N bond formation was achieved in moderate to excellent yields and the catalyst could be separated by magnetic decantation.
- Rafiee, Ezzat,Ataei, Ali,Joshaghani, Mohammad
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p. 219 - 222
(2015/12/31)
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- ANTI-HCMV COMPOSITIONS AND METHODS
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Novel compounds useful for treating and/or preventing HCMV infections are provided.
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Page/Page column 41
(2016/06/06)
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- Magnetic silica supported copper: A modular approach to aqueous Ullmann-type amination of aryl halides
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One-pot synthesis of a magnetic silica supported copper catalyst has been described via in situ generated magnetic silica (Fe3O 4@SiO2); the catalyst can be used for the efficacious amination of aryl halides in aqueous medium under microwave irradiation.
- Nasir Baig,Varma, Rajender S.
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p. 6568 - 6572
(2014/02/14)
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- Synthesis and structural characterization of palladium(II) thiosemicarbazone complex: Application to the Buchwald-Hartwig amination reaction
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A simple route to synthesize mononuclear palladium(II) thiosemicarbazone complex has been described. Elemental analysis, spectral methods and single crystal X-ray diffraction analysis were used to confirm the composition of the complex. The new complex acts as an active homogeneous catalyst for the Buchwald-Hartwig amination reaction of a wide range of aryl and heteroaryl halides (bromides and chlorides), including activating, neutral and deactivating substrates, with various secondary amines under optimized conditions.
- Prabhu, Rupesh Narayana,Ramesh, Rengan
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p. 1120 - 1124
(2013/03/13)
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- Ruthenium-catalyzed transfer hydrogenation of amino- and amido-substituted acetophenones
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The ruthenium-catalyzed transfer hydrogenation of electron-rich amino-substituted acetophenones is reported. Variation of the reductant, ligands, base, and solvent allowed reaction optimization. A key discovery was the use of 1,4-butanediol as an irreversible reducing agent, which significantly improved the conversion. A range of amino- and amido-substituted aryl ketones were explored, and they all gave the corresponding alcohols in good yield, which demonstrates the wider applicability of this process. The ruthenium-catalyzed reduction of electron-rich amino-substituted acetophenones with 1,4-butanediol as an irreversible reducing agent is reported. Optimization of the conditions and variation of the amino substituent are explored as is the use of amido- and sulfonamidoacetophenones with varying results. Copyright
- Watson, Andrew J. A.,Fairbanks, Antony J.
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supporting information
p. 6784 - 6788
(2013/11/06)
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- Cobalt-catalyzed electrophilic amination of arylzincs with N-chloroamines
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Roles reversed: An efficient cobalt-catalyzed electrophilic amination of arylzinc reagents has been achieved. A variety of functionalized arylzincs and N-chloroamines were coupled under mild conditions (see scheme). Both secondary and tertiary arylamines were obtained in moderate to excellent yields. Copyright
- Qian, Xin,Yu, Zailu,Auffrant, Audrey,Gosmini, Corinne
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p. 6225 - 6229
(2013/07/05)
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- Amination of electron deficient aryl chlorides promoted by nano sized Mg(OH)2 under transition metals free condition
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This paper presents the amination reactions of electron deficient aryl chlorides promoted by Mg(OH)2 without transition metals. Only using stoichiometric amount of nano sized Mg(OH)2, good to moderate isolated yields could be achieved in N-methylpyrrolidone (NMP) after 24 h at 150 °C.
- Cui, Zhi Hao,Meng, Zi Hui,Mi, Yan Qing,Wang, Peng,Wang, Qi,Zhao, Lin Man,Cui, Ke Jian,Yu, Fang,Xu, Zhi Bin
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experimental part
p. 137 - 140
(2012/06/18)
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- Microwave enhanced Claisen-Schmidt condensation: A green route to chalcones
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Chalcones have been synthesized under microwave irradiation by Claisen-Schmidt condensation between 4-piperidinoacetophenone and appropriately substituted benzeldehydes using NaOH-Al2O3 under solvent free conditions. Neat reactions on microwave irradiation (MWI) under solvent free conditions result in enhancement of yield and reaction rates. High conversion is obtained in absence of solvent. The protocol offers several advantages such as simple procedure, fast reaction rate, mild reaction conditions and excellent yield. Structure elucidation of synthesized compounds has been accomplished by elemental analysis and spectral data. All the compounds have been screened for antimicrobial activity by the cup-plate method.
- Singh, Jayant P.,Dulawat, Mangalshree,Jaitawat, Neetu,Chundawat, Sumer S.,Devpura, Anju,Dulawat, Shiv S.
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p. 1623 - 1627
(2013/01/15)
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- Antimalarial Activity of Newly Synthesized Chalcone Derivatives In Vitro
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Twenty-seven novel chalcone derivatives were synthesized using Claisen-Schmidt condensation and their antimalarial activity against asexual blood stages of Plasmodium falciparum was determined. Antiplasmodial IC50 (half-maximal inhibitory concentration) activity of a compound against malaria parasites in vitro provides a good first screen for identifying the antimalarial potential of the compound. The most active compound was 1-(4-benzimidazol-1-yl-phenyl)-3-(2, 4-dimethoxy-phenyl)-propen-1-one with IC50 of 1.1μg/mL, while that of the natural phytochemical, licochalcone A is 1.43μg/mL. The presence of methoxy groups at position 2 and 4 in chalcone derivatives appeared to be favorable for antimalarial activity as compared to other methoxy-substituted chalcones. Furthermore, 3, 4, 5-trimethoxy groups on chalcone derivative probably cause steric hindrance in binding to the active site of cysteine protease enzyme, explaining the relative lower inhibitory activity.
- Yadav, Neesha,Dixit, Sandeep K.,Bhattacharya, Amit,Mishra, Lokesh C.,Sharma, Manish,Awasthi, Satish K.,Bhasin, Virendra K.
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experimental part
p. 340 - 347
(2012/08/29)
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- A study of the Willgerodt-Kindler reaction to obtain thioamides and α-ketothioamides under solvent-less conditions
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In this paper, the results obtained in the synthesis of thioamides and α-ketothioamides by a modification of the Willgerodt-Kindler reaction, under solvent-free and noncatalyst conditions using IR energy as a source of activation, are presented. The use of IR energy in these reactions has been shown to lead to a mixture of thioamide and α-ketothioamide as the main products in most cases, with the latter predominating. The yields of α-ketothioamides from most of these reactions are better than those reported previously. To the best of our knowledge, this is the first time that IR energy has been applied to promote the Willgerodt-Kindler reaction.
- Valdez-Rojas, Jose Ernesto,Rios-Guerra, Hulme,Ramirez-Sanchez, Alma Leticia,Garcia-Gonzalez, Guadalupe,Alvarez-Toledano, Cecilio,Lopez-Cortes, Jose Guadalupe,Toscano, Ruben A.,Penieres-Carrillo, Jose Guillermo
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supporting information; experimental part
p. 567 - 573
(2012/08/08)
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- Selective functionalization of sp3 C - H bonds adjacent to nitrogen using (diacetoxyiodo)benzene (DIB)
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(Chemical Equation Presented) A PhI(OAc)2 mediated selective functionalization of sp3C - H bonds adjacent to a nitrogen atom has been reported. When piperidine derivates were used, direct diacetoxylation of α and β sp3 C - H adjacent to a nitrogen atom were observed to afford various cis-2,3-diacetoxylated piperidines. On the other hand, tetrahydroisoquinoline derivatives gave various α-C - H functionalized products in the presence of PhI(OAc)2. Nitroalkanes, dialkyl malonates, and β-keto ester are active participants in this coupling reaction. Meanwhile, α-amino nitriles can also be obtained by oxidative coupling of amineswithmalononitrile. 2009 American Chemical Society.
- Shu, Xing-Zhong,Xia, Xiao-Feng,Yang, Yan-Fang,Ji, Ke-Gong,Liu, Xue-Yuan,Liang, Yong-Min
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supporting information; experimental part
p. 7464 - 7469
(2010/01/06)
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- Study of the microwave-assisted hydrolysis of nitriles and esters and the implementation of this system in rapid microwave-assisted Pd-catalyzed amination
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Microwave-assisted hydrolysis of benzonitriles and methyl benzoates has been studied using a toluene/concd aq KOH two phase system in the presence and absence of phase transfer catalyst. Conditions to allow and avoid smooth hydrolysis could be identified. Based on the latter, the first microwave protocol which allows the rapid Pd-catalyzed amination of aliphatic amines with chlorobenzenes containing sensitive functional groups has been developed.
- Van Baelen, Gitte,Maes, Bert U.W.
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p. 5604 - 5619
(2008/09/21)
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- Synthesis of novel substituted 1,3-diaryl propenone derivatives and their antimalarial activity in vitro
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The synthesis of novel 1,3-diaryl propenone derivatives and their antimalarial activity in vitro against asexual blood stages of human malaria parasite, Plasmodium falciparum, are described. Chalcone derivatives were prepared via Claisen-Schmidt condensation of substituted aldehydes with substituted methyl ketones. Antiplasmodial IC50 (half maximal inhibitory concentration) activity of these compounds ranged between 1.5 and 12.3 μg/ml. The chloro-series, 1,2,4-triazole substituted chalcone was found to be the most effective in inhibiting the growth of P. falciparum in vitro while pyrrole and benzotriazole substituted chalcones showed relatively less inhibitory activity. This is the first report on antiplasmodial activity of chalcones with azoles on acetophenone ring.
- Mishra, Nidhi,Arora, Preeti,Kumar, Brajesh,Mishra, Lokesh C.,Bhattacharya, Amit,Awasthi, Satish K.,Bhasin, Virendra K.
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p. 1530 - 1535
(2008/09/21)
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- Structure-activity relationship study of a novel necroptosis inhibitor, necrostatin-7
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Necroptosis is a regulated caspase-independent cell death mechanism characterized by morphological features resembling non-regulated necrosis. Necrotatin-7 (Nec-7), a novel potent small-molecule inhibitor of necroptosis, is structurally distinct from previously described necrostatins (Nec-1, Nec-3, Nec-4 and Nec-5). Here, we describe a series of structural modifications and the structure-activity relationship (SAR) of the Nec-7 series for inhibiting necroptosis.
- Zheng, Weihong,Degterev, Alexei,Hsu, Emily,Yuan, Junying,Yuan, Chengye
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body text
p. 4932 - 4935
(2009/05/26)
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- α-Methylation at benzylic fragment of N-aryl-N′-benzyl ureas provides TRPV1 antagonists with better pharmacokinetic properties and higher efficacy in inflammatory pain model
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SAR studies for N-aryl-N′-benzyl urea class of TRPV1 antagonists have been extended to cover α-benzyl alkylation. Alkylated compounds showed weaker in vitro potencies in blocking capsaicin activation of TRPV1 receptor, but possessed improved pharmacokinetic properties. Further structural manipulations that included replacement of isoquinoline core with indazole and isolation of single enantiomer led to TRPV1 antagonists like (R)-16a with superior pharmacokinetic properties and greater potency in animal model of inflammatory pain.
- Gomtsyan, Arthur,Bayburt, Erol K.,Keddy, Ryan,Turner, Sean C.,Jinkerson, Tammie K.,Didomenico, Stanley,Perner, Richard J.,Koenig, John R.,Drizin, Irene,McDonald, Heath A.,Surowy, Carol S.,Honore, Prisca,Mikusa, Joe,Marsh, Kennan C.,Wetter, Jill M.,Faltynek, Connie R.,Lee, Chih-Hung
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p. 3894 - 3899
(2008/02/09)
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- Study of ultrasound promoted aromatic nucleophilic substitution of halobenzenes with amines
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The sonochemical nucleophilic aromatic substitution of substituted haloarenes with different amines were studied. The reaction course was found to be strongly depended on basicity, bulkiness, and boiling point of amines as well as on the electron-withdrawing property of the substituents.
- Meciarova, Maria,Toma, Stefan,Podlesna, Jana,Kiripolsky, Michal,Cisarova, Ivana
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- Scope and Limitations of the Pd/BINAP-Catalyzed Amination of Aryl Bromides
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Mixtures of Pd2(dba)3 or Pd(OAc)2 and BINAP catalyze the cross-coupling of amines with a variety of aryl bromides. Primary amines are arylated in high yield, and certain classes of secondary amines are also effectively transformed. The process tolerates the presence of several functional groups including methyl and ethyl esters, enolizable ketones, and nitro groups provided that cesium carbonate is employed as the base. Most reactions proceed to completion with 0.5-1.0 mol % of the palladium catalyst; in some cases, catalyst levels as low as 0.05 mol % Pd may be employed. Reactions are considerably faster if Pd(OAc)2 is employed as the precatalyst, and the order in which reagents are added to the reaction has a substantial effect on reaction rate. It is likely that the catalytic process proceeds via bis(phosphine)palladium complexes as intermediates. These complexes are less prone to undergo undesirable side reactions which lead to diminished yields or catalyst deactivation than complexes of the corresponding monodentate triarylphosphines.
- Wolfe, John P.,Buchwald, Stephen L.
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p. 1144 - 1157
(2007/10/03)
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- A new paradigm for biohydroxylation by Beauveria bassiana ATCC 7159
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The biohydroxylation of a series of amides and related amino, keto and hydrocarbon substrates by the fungal biocatalyst Beauveria bassiana ATCC 7159 has been examined. The product distributions, together with data obtained from selective inhibition experiments using the cyt.P-450 inhibitors isosafrole, 1-aminobenzotriazole and phenylacetylene, suggest that B. bassiana contains a range of hydroxylase enzymes with different substrate specificities. A paradigm is presented for the interpretation of the results of microbial hydroxylation and for the application of existing active site models for B. bassiana.
- Holland, Herbert L.,Morris, Terence A.,Nava, Phillip J.,Zabic, Mirjana
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p. 7441 - 7460
(2007/10/03)
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- A facile route to aryl amines: Nucleophilic substitution of aryl triflates
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The aromatic nucleophilic substitution (S(N)Ar) between aryl triflates and secondary amines has been studied. In the absence of solvent, the reaction proceeds at room temperature for nitro and cyano activated aryl triflates and requires higher temperatures in the case of carboxy activation. Variable triflate reactivity could be explained in terms of frontier molecular orbital theory. This methodology has been applied for the synthesis of substituted piperidyl pyridines.
- Schio, Laurent,Lemoine, Guy,Klich, Michel
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p. 1559 - 1562
(2007/10/03)
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- Amination of aryl bromides catalysed by supported palladium
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Palladium particles immobilised onto a metal oxide support or Pd(0), Pd(II) and [Pd(NH3)4]2+ in NaY zeolite have been prepared and characterised. They exhibit a good activity towards the amination of aryl bromides using secondary amines such as piperidine and diethyl amine with a good regio-selectivity for these reactions. Low Pd concentrations (1 mol%) are required to observe a reasonable regio-selectivity. The catalysts can easily be separated from the reaction mixture (filtration) and reused without loss of activity and selectivity. The electronic nature of the aryl halides plays an important role for both the reaction yields and the regio-control of the reaction. It depends on the relation of the direct amination via a benzyne intermediate versus the Pd-catalysed route.
- Djakovitch, Laurent,Wagner, Michael,Koehler, Klaus
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p. 225 - 234
(2007/10/03)
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- Aromatic nucleophilic substitutions under microwave irradiation
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In order to study the effect of microwave irradiation over aromatic nucleophilic substitutions at atmospheric pressure and in a homogeneous medium, experiments with disubstituted-benzenes and the nucleophiles piperidine and potassium t-butoxide, in refluxing DMSO or DMF, were carried out. The aromatic nucleophilic substitutions under microwave irradiation were 2.7 to 12 times faster than under conventional reflux.
- Salmoria, Gean V.,Dall'Oglio, Evandro,Zucco, Cesar
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p. 2471 - 2474
(2007/10/03)
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- Esters and amides of substituted phenyl acetic acids
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Esters and amides of substituted phenyl acetic acids having the formula wherein Q is a deprotonated residue of a polymer or macromolecular structure having a molecular weight of at least 1000 containing at least two primary and/or secondary amino groups and/or hydroxy groups;, n is an integer of at least 2;, R1 and R2 are independently selected from, hydrogen, halogen, alkyl, alkenyl, alkinyl or halo alkyl;, R3 is one or more substituents selected from halogen, alkyl, alkenyl or alkinyl, cycloalkyl, oxo-substituted alkylcycloalkyl, haloalkyl, alkoxy, alkenyloxy, alkinyloxy, alkylamino, alkenylamino, alkinylamino, alkysulfonyl, alkenylsulfonyl, alkinylsulfonyl, alkylsulfinyl, alkenylsulfinyl, alkinylsulfinyl, alkylsulfenyl, alkenylsulfenyl, alkinylsulfenyl, pyrrolyl, piperidinyl, benzoyl, imidazolpyridinyl, isoindolyl, oxo-substituted isoindolyl, thionylcarbonyl, phenyl, phenoxy and halo-substituted phenoxy, are useful in the treatment of colonic polyps.
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- Reductive one batch synthesis of N-arylpiperidines from primary amines and glutaraldehyde
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The construction of the piperidine ring about an aromatic nitrogen atom, by a 5C + N reductiye condensation reaction, using glutaraldehyde (pentanedial) and sodium borohydride in acidic water/methanol medium is described. The reaction is fast, affords good to excellent yields and appears insensitive to electronic effects and severe steric hindrance; it is found to be compatible with a large variety of aryl substituents, including nitro and oxo groups.
- Verardo,Giumanini,Favret,Strazzolini
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p. 447 - 450
(2007/10/02)
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- Studies of Tetriary Amine Oxides. 9. Thermal Rearrangement of 1-(4-Substituted-phenyl)piperidine N-Oxides to the Corresponding N-Hydroxylamines
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(4-Substituted - phenyl)piperidine N-oxides undergo a thermal rearrangement to O-arylhydroxylamines.Electron withdrawing substituents are essential for the rearrangement and must be ortho or para relative to the N-O function.The reaction has been found to be first order in substrate when rates were measured in dioxane, and the activation parameters were calculated.The order of reactivity in this rearrangement is NO2 >> CN > COPh > COMe > COOEt > CONH2.The rates correlate very well with ?- constants and the ρ value was positive and large (+3.6) pointing to a highly po lar activated complex with an electron-rich reaction center.All results strongly support an intramolecular cyclic mechanism.
- Khuthier, Abdul-Hussain,Al-Mallah, Khawla Y.,Hanna, Salim Y.,Abdulla, Noor-Aldeen I.
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p. 1710 - 1713
(2007/10/02)
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