- Iodine-Catalyzed Double [4+2] Oxidative Annulations for the Synthesis of Bipyrazines from Ketones and Diamines by a Domino Strategy
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An iodine-catalyzed double [4+2] oxidative annulation of ketones and diamines is described. A multi-pathway coupled domino strategy has been developed for the synthesis of substituted dimeric pyrazines under metal-free conditions. One C?C and four C?N bonds are formed during this double [4+2] oxidative annulation process from two ketones and two diamines. (Figure presented.).
- Ding, Yuxin,Zhang, Ruiqin,Ma, Renchao,Ma, Yongmin
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p. 355 - 361
(2021/10/19)
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- Catalytic activity of Mg-Al hydrotalcites and derived mixed oxides for imination reactionsviaan oxidative-dehydrogenation mechanism
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The catalytic activities of Mg-Al hydrotalcites and derived Mg-Al mixed oxides were studied for the imination of benzylic substrates (benzyl amine and benzyl alcohol), with aniline as a model reaction, to establish a green and cost-effective catalytic (precious metal free) process for imination and tandem reactions utilizing alcohols as reagents. The Mg-Al mixed oxide (Mg/Al ratio = 3.0) was found to be an efficient catalyst for imination reactions to synthesize cross-imines with high selectivity as well as for tandem reactions of alcohols. Basic sites of catalysts adsorb benzylic substrates through the hydrogen of their functional groups (-NH2/-OH) and activate (weaken) benzylic C-H bonds for hydride elimination. Thus, basic sites catalyze the reaction by activating benzylic substrates for oxidative-dehydrogenation (i.e., deprotonation followed by hydride elimination with the help of oxygen) to produce reactive imine/carbonyl intermediates, which undergo subsequent nucleophilic reactions with amine.
- Vala, Naresh,Joshi, Pradyuman A.,Mishra, Manish
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supporting information
p. 8859 - 8868
(2020/06/08)
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- Photocatalytic coupling of amines to imidazoles using a Mo-ZnIn2S4 catalyst
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Substituted imidazoles are traditionally synthesized by co-condensation of multiple feedstocks. Herein, we report a new route for the synthesis of substituted imidazoles via photocyclization of readily available amines at room temperature. The reaction is achieved by the visible-light-induced C-C/C-N bond coupling and subsequent dehydrogenation reaction over Mo-ZnIn2S4 as a heterogeneous photocatalyst. A wide range of amines were converted into the corresponding tri- and tetra-substituted imidazoles with up to 96% total yields. The simplicity, high efficiency and mild condition merits of this new reaction will enable it to be useful in synthetic transformations.
- Wang, Min,Li, Lihua,Lu, Jianmin,Luo, Nengchao,Zhang, Xiaochen,Wang, Feng
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p. 5172 - 5177
(2017/11/09)
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- Convenient one-step synthesis of cis-2,4,5-triarylimidazolines from aromatic aldehydes with urea
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A simple and efficient method has been developed for the synthesis of cis-2,4,5-triarylimidazolines based on a one-step procedure of aldehydes and urea in the presence of cesium carbonate. Taylor & Francis Group, LLC.
- Wang, Fei,Liao, Qian,Xi, Chanjuan
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experimental part
p. 905 - 913
(2012/02/01)
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- Cycloaddition reactions of 1,3-diazabuta-1,3-dienes with alkynyl ketenes
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The cycloaddition reactions of 'all-carbon' 1,3-diazabuta-1,3-dienes with a few conjugated and unconjugated alkynyl ketenes are described. The reactions provide some interesting azetidinones and dihydropyrimidinones bearing an alkynyl moiety. The regiochemistry of cycloadduct is related with the degree of conjugation of the alkynyl ketene. Moreover, two alternative approaches to 'all-carbon' 1,3-diazabuta-1,3-dienes are reported.
- Abbiati, Giorgio,Contini, Alessandro,Nava, Donatella,Rossi, Elisabetta
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experimental part
p. 4664 - 4670
(2009/10/09)
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- Nuclear factor-κB mediated inhibition of cytokine production by imidazoline scaffolds
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The mammalian nuclear transcription factor NF-κB is responsible for the transcription of multiple cytokines, including the pro-inflammatory cytokines tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6). Elevated levels of pro-inflammatory cytokines play an important role in the pathogenesis of inflammatory disorders such as rheumatoid arthritis (RA). Inhibition of the pro-inflammatory transcription factor NF-κB has therefore been identified as a possible therapeutic treatment for RA. We describe herein the synthesis and biological activity of a series of imidazoline-based scaffolds as potent inhibitors of NF-κB mediated gene transcription in cell culture as well as inhibitors of TNF-α and IL-6 production in interleukin 1 beta (IL-1β) stimulated human blood.
- Kahlon, Daljinder K.,Lansdell, Theresa A.,Fisk, Jason S.,Hupp, Christopher D.,Friebe, Timothy L.,Hovde, Stacy,Jones, A. Daniel,Dyer, Richard D.,Henry, R. William,Tepe, Jetze J.
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supporting information; experimental part
p. 1302 - 1309
(2009/12/26)
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- A convenient preparation of enantiomerically pure (+)-(1R,2R)- and (-)-(1S,2S)-1,2-diamino-1,2-diphenylethanes
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A gram-scale preparation of (1S,2S)- and (1R,2R)-1,2-diamino-1,2- diphenylethanes, (1S,2S)-1 and (1R,2R)-1, is reported via (±)-iso-amarine 4. Strategically, the activation of (±)-iso-amarine 4 for hydrolysis to the required diamines and enantiomeric resolution is achieved simultaneously by formation of two separable diastereoisomeric N-acylamidines 5 and 6 derived from direct DCC-mediated coupling of (±)-iso-amarine 4 with (R)-acetylmandelic acid. iso-Amarine 4 is conveniently obtained from amarine 3, and a one-pot synthesis of the latter is reported from benzaldehyde and hexamethyldisilazane as catalysed by benzoic acid.
- Braddock, D. Christopher,Redmond, Joanna M.,Hermitage, Stephen A.,White, Andrew J. P.
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p. 911 - 916
(2007/10/03)
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- Alumina-ammonium acetate as an efficient reagent for the one-pot synthesis of cis-2,4,5-triarylimidazolines from aromatic aldehydes
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A simple, efficient, and new method has been developed for the synthesis of 2,4,5-triarylimidazolines from aldehydes through a one-pot reaction of aldehydes in the presence of alumina-ammonium acetate under solvent-free conditions using microwave irradiation. This method is easy, rapid, one-pot and good to high-yielding reaction for the synthesis of 2,4,5-triarylimidazolines.
- Kaboudin, Babak,Saadati, Fariba
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p. 353 - 357
(2007/10/03)
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- Synthesis and SAR of novel 4,5-diarylimidazolines as potent P2X7 receptor antagonists
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The synthesis and SAR of a series of potent P2X7 receptor antagonists is described. The synthesis featured high-throughput solution- and solid-phase techniques including a microwave induced imidazoline formation. A series of 4,5-diarylimidazoline libraries were prepared using high-throughput solid-phase and microwave techniques. The compounds were evaluated as P2X 7 antagonists and their SAR is described.
- Merriman, Gregory H.,Ma, Liang,Shum, Patrick,McGarry, Daniel,Volz, Frank,Sabol, Jeffrey S.,Gross, Alexandre,Zhao, Zhicheng,Rampe, David,Wang, Lin,Wirtz-Brugger, Friederike,Harris, Bruce A.,Macdonald, Douglas
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p. 435 - 438
(2007/10/03)
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- Studies on the synthesis of 1-aminoalkylphosphonates from aldehydes using silica-supported ammonium hydrogen carbonate
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Studies on the use of silica-supported ammonium hydrogen carbonate as an efficient reagent for the synthesis of 1-amino-phosphonates under microwave irradiation in solvent-free conditions is reported. Investigations showed that this reaction proceeds by the formation of methanediamine as an intermediate. The reaction in the absence of diethyl phosphite gave cis-imidazolines as the major products.
- Kaboudin, Babak,Saadati, Fariba
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p. 1249 - 1252
(2007/10/03)
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- Synthesis of N,N-di(arylmethylidene)arylmethanediamines by flash vacuum pyrolysis of arylmethylazides
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Flash vacuum pyrolysis of arylmethylazides 7a-d gave 2,4-diazapentadienes 5a-d in high yield (76-92%). The thermal cyclization of 5a-d gave cis-imidazolines 1a-d, further heating or Swern oxidation of 1a-d gave dehydrogenated products, imidazoles 2a-d.
- Chou, Chin-Hsing,Chu, Li-Tse,Chiu, Shao-Jung,Lee, Chin-Fan,She, Yao-Teng
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p. 6581 - 6584
(2007/10/03)
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- Microwave-assisted rapid and selective synthesis of cis- and trans-2,4,5-triarylimidazolines from aromatic aldehydes
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Microwave irradiation of a mixture of aromatic aldehydes and hexamethyldisilazane in the presence of a solid catalyst such as alumina afforded methanediamines which were efficiently converted to either cis- or trans-2,4,5-triarylimidazolines depending on the base used. A one-pot selective synthesis of cis- and transimidazolines from aromatic aldehydes was achieved under microwave irradiation.
- Uchida, Hitoshi,Tanikoshi, Hirofumi,Nakamura, Shuichi,Reddy, Paidi Yella,Toru, Takeshi
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p. 1117 - 1120
(2007/10/03)
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- Solvent-free efficient synthesis of 2,4,5-triarylimidazolines from aromatic aldehydes and hexamethyldisilazane
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A one-step preparation of 2,4,5-triarylimidazolines from aromatic aldehydes was accomplished by heating with hexamethyldisilazane under solvent-free conditions. This reaction provides a convenient preparative method for triarylimidazolines having a variety of aryl groups.
- Uchida, Hitoshi,Shimizu, Takashi,Reddy, Paidi Yella,Nakamura, Shuichi,Toru, Takeshi
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p. 1236 - 1240
(2007/10/03)
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- Regioselective synthesis of cis- and trans-2,4,5-triarylimidazolines and 2,4,5-triarylimidazoles from available reagents
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Novel data were obtained concerning the reaction of aromatic aldehydes with ammonia. A preparative method for the synthesis of new substituted 1,3,5-triaryl-2,4-diazapenta-1,4-dienes was developed. These products are the starting reactants for syntheses of cis- and trans-2,4,5-triaryl-2-imidazolines and 2,4,5-triarylimidazoles.
- Lozinskaya,Tsybezova,Proskurnina,Zefirov
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p. 674 - 678
(2007/10/03)
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- Hexamethyldisilazane as an amination agent: One-pot synthesis of isoamarine and its pyridine analogue
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The ability of hexamethyldisilazane to convert aldehydes into Schiff bases was adapted to the one-pot syntheses of isoamarine and its pyridine analogue.
- Mistryukov
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- ASYMMETRIC REDUCTION OF ACETOPHENONE WITH CHIRAL REAGENTS FROM LITHIUM TETRAHYDROALUMINATE AND CHIRAL 1,2-DIOL OR DIAMINE AS STUDIED BY ALUMINUM-27 NUCLEAR MAGNETIC RESONANCE
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Asymmetric reduction of acetophenone with chiral reagents from lithium tetrahydroaluminate and (1S,2S)-1,2-diphenylethanediol or (1S,2S)-N,N'-diethyl-1,2-diphenylethanediamine in the presence or absence of added ethanol is studied by aluminum-27 NMR spectroscopy.
- Yamashita, Junzo,Tomiyama, Shigemi,Hashimoto, Harukichi,Kitahara, Keiichi,Sato, Hisao
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p. 749 - 752
(2007/10/02)
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