- Diastereoselective construction of cyclopent-2-enone-4-ols from aldehydes and 1,2-allenones catalyzed by N-heterocyclic carbene
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Cyclopent-2-enone-4-ols have been prepared highly diastereoselectively from readily available aromatic aldehydes and 1,2-allenones catalyzed by N-heterocyclic carbene. Mechanistic studies showed that there are four possible pathways.
- Ma, Dengke,Fu, Chunling,Ma, Shengming
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Read Online
- Functionalizing tetraphenylpyrazine with perylene diimides (PDIs) as high-performance nonfullerene acceptors
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Perylene diimide (PDI)-based small molecular acceptors with a three-dimensional structure are thought to be essential for efficient photocurrent generation and high power conversion efficiencies (PCEs). Herein, a couple of new perylene diimide acceptors (
- Li, Gang,Yang, Shufan,Liu, Tao,Li, Jiewei,Yang, Wenbin,Luo, Zhenghui,Yan, Cenqi,Li, Dandan,Wang, Xinyu,Cui, Guanwei,Yang, Tao,Xu, Liang,Zhan, Shun-Ze,Huo, Lijun,Yan, He,Tang, Bo
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Read Online
- Insights into the synthesis of hexaaminobenzene hydrochloride: An entry to hexaazatriphenylenes
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Polycyclic N-heteroaromatic systems and particularly, the dipyrazino[2,3-f:2′,3′-h]quinoxaline also known as 1,4,5,8,9,12-hexaazatriphenylene (HAT) displays very useful optoelectronic properties. Its synthesis through condensation of functionalized 1,2-diketones and hexaaminobenzene is often applied on laboratory scale. Hexaaminobenzene could be prepared from 4-nitroaniline but, despite its many applications, the experimental protocol is not trivial and should by carefully controlled in each step. In this work, we presented an efficient and reproducible 4 steps synthesis of hexaaminobenzene hydrochloride and a comprehensive analysis of reactions conditions and products formed in all synthetic steps. As evidence, this aromatic polyamine was effectively condensed with 1,2-di(4-bromophenyl)-1,2-ethanedione affording a synthetically versatile HAT derivative for the application in the design of organic materials.
- Comba, María Betina,Libonatti, Bernardo,Mangione, María Inés,Spanevello, Rolando A.,Vázquez, Darián
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- Organocatalytic Synthesis of Substituted Vinylene Carbonates
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The organocatalytic synthesis of substituted vinylene carbonates from benzoins and acyloins was studied using diphenyl carbonate as a carbonyl source. A range of N-Heterocyclic Carbene (NHC) precursors were screened and it was found that imidazolium salts were the most active for this transformation. The reaction occurs at 90 °C under solvent-free conditions. A wide range of substituted vinylene carbonates (symmetrical and unsymmetrical, aromatic or aliphatic), including some derived from natural products, were prepared with 20–99% isolated yields (24 examples). The reaction was also developed using thermomorphic polyethylene-supported organocatalysts as recoverable and recyclable species. The use of such species facilitates the workup and allows the synthesis of vinylene carbonates on the preparative scale (>30 g after 5 runs). (Figure presented.).
- Onida, Killian,Haddleton, Alice J.,Norsic, Sébastien,Boisson, Christophe,D'Agosto, Franck,Duguet, Nicolas
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supporting information
p. 5129 - 5137
(2021/09/18)
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- ORGANIC COMPOUNDS AND ORGANIC LIGHT EMITTING DISPLAY DEVICE USING THE SAME
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The present disclosure relates to an organic compound and an organic light emitting display device using the same wherein the organic compound is represented by Chemical Formula 1 and a display device using the organic compound. The organic compound represented by Chemical Formula 1 has excellent electron transport properties and durability and is used for an electron transport layer of an organic light emitting element, thereby lowering a driving voltage and improving the luminous efficiency and lifetime. (In the above Chemical Formula 1, at least two of X1, X2 and X3 are N, Y1 and Y2 are each independently a substituted or unsubstituted phenylene group or a single bond, at least one of Ar1 and Ar2 is selected from a substituted or unsubstituted triazine group, a functional group represented by Chemical Formula 2 and a functional group represented by Chemical Formula 3.)
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Paragraph 0131; 0132
(2021/07/02)
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- Synthesis and in vitro anticancer activities of selenium N-heterocyclic carbene compounds
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Fourteen novel selenium N-heterocyclic carbene (Se-NHC) compounds derived from 4,5-diarylimidazole were designed, synthesized, and evaluated as antiproliferative agents. Most of them were more effective toward A2780 ovarian cancer cells than HepG2 hepatocellular carcinoma cells. Among them, the most active compound 2b was about fourfold more active than the positive control ebselen against A2780 cells. In addition, this compound displayed twofold higher cytotoxicity to A2780 cells than to IOSE80 normal ovarian epithelial cells. Further studies revealed that 2b could induce reactive oxygen species production, damage mitochondrial membrane potential, block the cells in the G0/G1 phase, and finally promote A2780 cell apoptosis.
- Huang, Sheng,Sheng, Xinyu,Bian, Mianli,Yang, Zhibin,Lu, Yunlong,Liu, Wukun
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p. 435 - 444
(2021/07/14)
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- Application of N-heterocyclic carbene selenium-gold compound in preparation of carbapenem-resistant acinetobacter baumannii drug
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The invention discloses application of an N-heterocyclic carbene selenium-gold compound in preparation of a novel antibacterial drug resistant to carbapenem acinetobacter baumannii infection, and belongs to the technical field of drug preparation. According to the N-heterocyclic carbene selenium-gold compound, selenium-containing imidazole N-heterocyclic carbene selenium is used for replacing a thiosaccharide ligand in a gold nofen structure; the reaction activity of Au-Se in the N-heterocyclic carbene selenium-gold compound is higher than that of an Au-S bond, so that the Au-S bond in a Jinnofen structure can be prevented from being easily damaged by reducing mercaptan to a certain extent; and toxic and side effects are caused by metabolism before reaching a target spot. In-vitro antibacterial activity shows that IC50 of the compounds H7 and H8 in inhibition of carbapenem-resistant acinetobacter baumannii is 3.34 mu M and 4.67 mu M, MIC of the same are both 10 mu M, and MBC of the same are both 20 mu M. The animal in-vivo administration also shows a good anti-drug-resistant bacterium effect, which proves that the compound can significantly prolong the survival time of mice infected by drug-resistant bacteria, and has important practical application value.
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Paragraph 0024; 0029-0032
(2021/07/21)
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- Zinc salt-catalyzed reduction of α-aryl imino esters, diketones and phenylacetylenes with water as hydrogen source
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The zinc salt-catalyzed reduction of α-aryl imino esters, diketones and phenylacetylenes with water as hydrogen source and zinc as reductant was successfully conducted. The presented method provides a low-cost, environmentally friendly and practical preparation of α-aryl amino esters, α-hydroxyketones and phenylethylenes. By using D2O as deuterium source, the corresponding products were obtained in high efficiency with excellent deuterium incorporation rate, which gives a cheap and safe tool for access to valuable deuterium-labelled compounds. This journal is
- Shen, Guoli,Liu, Haojie,Chen, Jingchao,He, Zhenxiu,Zhou, Yongyun,Wang, Lin,Luo, Yang,Su, Zhimin,Fan, Baomin
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supporting information
p. 3601 - 3610
(2021/05/04)
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- Preparation and Application of Silica Films Supported Imidazolium-Based Ionic Liquid as Efficient and Recyclable Catalysts for Benzoin Condensations
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Abstract: Two silica films -immobilized imidazolium-based ionic liquids (TMICl @silica films) were prepared, characterized and utilized as efficient catalysts for the benzoin reaction. Combined characterization results from FT-IR, elemental analysis, N2 adsorption–desorption isotherms and SEM, suggested that the imidazolium-based ionic liquids were successfully immobilized on the silica films. Moreover, the catalytic performance tests demonstrated that silica films immobilized imidazolium-based ionic liquids (ILs) exhibited excellent activity for the benzoin reactions of aromatic aldehydes. The influence of catalyst concentration, temperature and reaction duration on the catalytic activity were investigated by employing 0.7TMICl @silica film(catalyst C) as the catalyst. The results also showed that the benzoin condensations of aromatic aldehydes could give desired products with satisfactory yields under the optimized conditions. Additionally, the catalyst can be effortlessly separated by filtration and reused more than five times without significant loss of activity. Graphic Abstract: [Figure not available: see fulltext.]
- Qian, Cunwei,Yao, Changsheng,Yang, Liujun,Yang, Bo,Liu, Shuchun,Liu, Zongtang
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p. 1389 - 1396
(2019/11/21)
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- Pendant Alkoxy Groups on N-Aryl Substitutions Drive the Efficiency of Imidazolylidene Catalysts for Homoenolate Annulation from Enal and Aldehyde
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Hydrogen-transfer in the tetrahedral intermediate generated from an imidazolylidene catalyst and α,β-unsaturated aldehyde forms a conjugated Breslow intermediate. This is a critical step affecting the efficiency of the NHC-catalyzed γ-butyrolactone formation via homoenolate addition to aryl aldehydes. A novel type of imidazolylidene catalyst with pendant alkoxy groups on the ortho-N-aryl groups is described. Catalyst of this sort facilitates the formation of the conjugated Breslow intermediate. Studies of the rate constants for homoenolate annulation affording γ-butyrolactones, reveal that introduction of the oxygen atoms in the appropriate position of the N-aryl substituents can increase the efficiency of imidazolylidene catalysts. Structural and mechanistic studies revealed that pendant alkoxy groups can be located close to the proton of the tetrahedral intermediate, thereby facilitating the proton transfer.
- Kyan, Ryuji,Mase, Nobuyuki,Narumi, Tetsuo,Sato, Kohei
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supporting information
p. 19031 - 19036
(2020/08/25)
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- Synthesis and properties of triphenylamine functionalized tetrathiafulvalene
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A hybrid conjugated molecule TTPA-TTF was designed and synthesized by combing a tetrathiafulvalene core with tetra-triphenylamine derivative functionalized at the 4,4′,5,5′- positions. Studies revealed TTPA-TTF exhibits good thermal stability and hole mob
- Tian, Xia,Qian, Fang,Wu, Min,Liang, Xiaozhong,Zhang, Fang,Li, Da,Guo, Kunpeng,Liu, Zhike,Li, Jie
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supporting information
(2020/04/24)
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- Fast-Synthesis of α-Phosphonyloxy Ketones as Drug Scaffolds in a Capillary Microreactor
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A simple, room temperature approach for the fast single-step synthesis of α-phosphonyloxy ketone, a drug scaffold, has been developed which involves highly reactive species i.e., 1,2-dicarbonyls that readily react with trialkyl phosphites and formic acids in batch as well as in continuous-flow with the flow rate of 3 ml/min (tR = ~4 s). The present approach reduced the synthesis time from hours to minutes in batch, which was further lowered to a few seconds precisely controlled by single capillary microfluidics. A wide range of 1,2-dicarbonyl derivatives were smoothly transformed to their corresponding α-phosphonyloxy ketones in moderate to good yields (50–82 %) under optimized flow-reaction conditions. Further, the α-phosphonyloxy ketones produced can be utilized in batch process to form benzoin, oxazole core, and α,α′-diarylated carbonyl compounds in 82 %, 50 %, and 54 % yields, respectively, which are alternative key precursors/scaffolds of natural products and active pharmaceutical ingredients (APIs).
- Ramanjaneyulu, Bandaru T.,Vidyacharan, Shinde,Yim, Se Jun,Kim, Dong-Pyo
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supporting information
p. 7730 - 7734
(2019/12/24)
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- The Direct Conversion of α-Hydroxyketones to Alkynes
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Alkynes are highly important functional groups in organic chemistry, both as part of target structures and as versatile synthetic intermediates. In this study, a protocol for the direct conversion of α-hydroxyketones to alkynes is reported. In combination with the variety of synthetic methods that generate the required starting materials by forming the central C-C bond, it enables a highly versatile fragment coupling approach toward alkynes. A broad scope for this novel transformation is shown alongside mechanistic insights. Furthermore, the utility of our protocol is demonstrated through its application in concert with varied α-hydroxyketone syntheses, giving access to a broad spectrum of alkynes.
- Ghiringhelli, Francesca,Nattmann, Lukas,Bognar, Sabine,Van Gemmeren, Manuel
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p. 983 - 993
(2019/01/24)
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- Benzoin compound preparing method
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The invention provides a benzoin compound preparing method. Specifically, the benzoin compound preparing method takes mesoporous material immobilized imidazolium salt ion liquid as catalysts to catalyze aromatic aldehydes into various benzoin compounds. T
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Paragraph 0068; 0069
(2019/05/02)
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- Tetra pyridine pheryl pyrazine, and preparation method and applications thereof
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The invention belongs to the technical field of organic polymer luminescent material, and provides tetra pyridine pheryl pyrazine which is used for solving problems in the prior art that conventionalaggregation-induction-induced emission ligand preparatio
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Paragraph 0032-0035
(2019/09/14)
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- A new rhodium(I) NHC complex inhibits TrxR: In vitro cytotoxicity and in vivo hepatocellular carcinoma suppression
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Thioredoxin reductase (TrxR) is often overexpressed in different types of cancer cells including hepatocellular carcinoma (HCC) cells and regarded as a target with great promise for anticancer drug research and development. Here, we have synthesized and characterized nine new designed rhodium(I) N-heterocyclic carbene (NHC) complexes. All of them were effective towards cancer cells, especially complex 1e was more active than cisplatin and manifested strong antiproliferative activity against HCC cells. In vivo anticancer studies showed that 1e significantly repressed tumor growth in an HCC nude mouse model and ameliorated liver lesions in a chronic HCC model caused by CCl4. Notably, a mechanistic study revealed that 1e can strongly inhibit TrxR system both in vitro and in vivo. Furthermore, 1e promoted intracellular ROS accumulation, damaged mitochondrial membrane potential, promoted cancer cell apoptosis and blocked the cells in the G1 phase.
- Fan, Rong,Bian, Mianli,Hu, Lihong,Liu, Wukun
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supporting information
(2019/10/01)
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- Four-phenyl pyrazine small molecule derivatives, four-phenyl pyrazine polymer and aggregation induced material
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The invention discloses a tetrapherylpyrazine low-molecular-weight derivate, a tetrapherylpyrazine polymer and an aggregation-induced emission material. The tetrapherylpyrazine low-molecular-weight derivate is of a structure as shown in a formula (1), whe
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Paragraph 0159-0162
(2017/08/14)
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- Base-Free Asymmetric Transfer Hydrogenation of 1,2-Di- and Monoketones Catalyzed by a (NH)2P2-Macrocyclic Iron(II) Hydride
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The hydride isonitrile complex [FeH(CNCEt3)(1 a)]BF4 (2) containing a chiral P2(NH)2 macrocycle (1 a), in the presence of 2-propanol as hydrogen donor, catalyzes the base-free asymmetric transfer hydrogenation (ATH) of prostereogenic ketones to alcohols and the hemihydrogenation of benzils to benzoins, which contain a base-labile stereocenter. Benzoins are formed in up to 83 % isolated yield with enantioselectivity reaching 95 % ee. Ketones give the same enantioselectivity observed with the parent catalytic system [Fe(CNCEt3)2(1 a)] (3 a) that operates with added NaOtBu.
- De Luca, Lorena,Mezzetti, Antonio
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supporting information
p. 11949 - 11953
(2017/09/20)
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- De Novo Synthesis of α-Hydroxy Ketones by Gallic Acid-Promoted Aerobic Coupling of Terminal Alkynes with Diazonium Salts
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An unprecedented metal-free direct preparation of unprotected α-hydroxy ketones from terminal alkynes under mild conditions with diazonium salts as the arene source and without the requirement of irradiation is described. The process is general and fully compatible with a wide variety of substitution in both reactants. Experimental and computational evidence strongly suggest the involvement of radical species in the transformation.
- Alcaide, Benito,Almendros, Pedro,Fernández, Israel,Herrera, Fernando,Luna, Amparo
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supporting information
p. 17227 - 17230
(2017/11/23)
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- NaBrO3/bmim[HSO4]: a versatile system for the selective oxidation of 1,2-diols, α-hydroxyketones, and alcohols
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Abstract: Sodium bromate with bmim[HSO4] has been found to be an excellent oxidizing agent in aqueous medium. NaBrO3:bmim[HSO4] oxidized 1,2-diols, α-hydroxyketones, and alcohols to the corresponding carbonyl compounds in excellent yields. This method offers advantages such as low cost reagents, aqueous reaction conditions, moderate temperatures and short reaction times and hence environmentally benign reaction. Moreover, the ionic liquid bmim[HSO4] could be recycled for at least three times without loss of significant activity. Graphical abstract: [Figure not available: see fulltext.]
- Khurana, Jitender M.,Lumb, Anshika,Chaudhary, Ankita
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p. 381 - 386
(2017/02/10)
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- Synthesis and photoluminescence properties of star-shaped 2,3,6,7-tetrasubstituted benzo[1,2-b:4,5-b′]difurans
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A new reaction of α-haloketones with hydroquinones leading to highly fluorescent star-shaped 2,3,6,7-tetrasubstituted benzodifurans is described. Thus 2,3,6,7-tetrakis(4-bromophenyl)-4,8-didecylbenzo[1,2-b:4,5-b′]difuran, the core of benzodifuran stars, w
- Bosiak, Mariusz J.,Trzaska, Piotr,K?dziera, Dariusz,Adams, J?rg
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p. 199 - 208
(2016/03/19)
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- Self-supported N-heterocyclic carbenes and their use as organocatalysts
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The study of N-heterocyclic carbenes (NHCs) as organocatalysts has proliferated in recent years, and they have been found to be useful in a variety of reactions. In an attempt to further expand their utility and to study their recyclability, we designed and synthesized a series of self-supported NHCs in which the catalytic carbene groups form part of a densely functionalized polymer backbone, and studied them as organocatalysts. Of the self-Supported NHCs examined, a benzimidazole derived polymer with flexible linkers connecting the catalytic groups was found to be the most efficient organocatalyst in a model benzoin condensation reaction, and thus it was used in a variety of such reactions, including some involving catalyst recycling. Furthermore, it was also used to catalyze a set of redox esterification reactions involving conjugated unsaturated aldehydes. In all of these reactions the catalyst afforded good yield of the desired product and its polymeric nature facilitated product purification.
- Ma, Shuang,Toy, Patrick H.
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- Triphenylamine-functionalized tetraphenylpyrazine: Facile preparation and multifaceted functionalities
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Aggregation-induced emission (AIE) is a unique photo-physical phenomenon and has become an emerging and hot research area. With the enthusiastic efforts paid by researchers, hundreds of AIE-active luminogens (AIEgens) have been generated but heterocyclic AIEgens are rarely reported. Recently, we enriched the family of AIEgens and reported a pyrazine-based AIEgen of tetraphenylpyrazine (TPP), which could be facilely functionalized by a post-synthetic strategy. In this work, we further expanded the TPP-based AIE system by covalently attaching one, two or four electron-donating triphenylamine moieties to the TPP core via Suzuki coupling, and TPP-TPA, TPP-2TPA and TPP-4TPA were produced, respectively. Thanks to their donor-π-acceptor structures, these luminogens exhibit multi-functional properties, such as excellent thermal stability (up to 504°C), large molar absorptivity, bright emission in the solid state (quantum yields up to 35.2%), solvatochromism, and high two-photon absorption cross-sections (up to 480 GM). Furthermore, using TPP-TPA as the emitting layer, a triple-layer device was fabricated and a turn-on voltage, maximum luminance, current efficiency, power efficiency, and external quantum efficiency of 3.7 V, 17 459 cd m-2, 5.49 cd A-1, 3.18 lm W-1 and 2.88% were realized, respectively. These results indicate a huge potential to develop high-tech applications based on these TPP-based AIEgens.
- Chen, Ming,Nie, Han,Song, Bo,Li, Lingzhi,Sun, Jing Zhi,Qin, Anjun,Tang, Ben Zhong
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supporting information
p. 2901 - 2908
(2016/04/26)
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- A new protocol for one-pot synthesis of tetrasubstituted pyrroles using tungstate sulfuric acid as a reusable solid catalyst
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A variety of tetrasubstituted pyrroles were synthesized in good yields in a one-pot, three-component reaction of α-hydroxyketones, malononitrile, and ammonium acetate using tungstate sulfuric acid (TSA) under solvent-free conditions.
- Farahi, Mahnaz,Davoodi, Mahdiyeh,Tahmasebi, Mina
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p. 1582 - 1584
(2018/03/22)
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- Highly enantioselective hydrogenation of o-alkoxy tetrasubstituted enamides catalyzed by a Rh/(R, S)-josiphos catalyst
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Rh/(R,S)-JosiPhos complex-catalyzed asymmetric hydrogenation of o-alkoxy tetrasubstituted enamides has been achieved, and it furnished a set of β-amino alcohol analogues in high yields and excellent enantiomeric excesses (>99% conversion, up to 99% ee).This method provides valuable chiral building blocks in chiral pharmaceuticals and useful motifs for catalysts.
- Meng, Jingjing,Gao, Min,Lv, Hui,Zhang, Xumu
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supporting information
p. 1842 - 1845
(2015/04/27)
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- Synthesis of functionalized γ-lactones via a three-component cascade reaction catalyzed by consecutive N-heterocyclic carbene systems
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Two consecutive N-heterocyclic carbene (NHC) catalytic systems were combined in a one-pot cascade reaction for the assembly of aromatic aldehydes and 2-haloenals into a structurally complex γ-lactone backbone. To our knowledge, this is the first report of NHC-catalyzed [3 + 2] annulation of α,β-unsaturated acylazoliums with 1,2-bisnucleophiles.
- Zhao, Qian,Han, Bo,Wang, Biao,Leng, Hai-Jun,Peng, Cheng,Huang, Wei
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p. 26972 - 26976
(2015/03/30)
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- Unexpected transformation of aldehydes into benzoins with Copper(I)/Samarium
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The reductive coupling of aldehydes to afford pinacolic alcohols using all kinds of reducing agents involving samarium is well known. In this report, however, treatment of aromatic aldehydes with Cu(I)/Sm system produces benoins and/or benzils in good yields. A possible mechanism is proposed where Cu(I) not only activates the Sm metal but also promotes the dehydrogenation of the intermediates, during which a Cu(III) species may be involved. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications for the following free supplemental resource(s): Full experimental and spectral details.]
- Liu, Yongjun,Wang, Hui,Fu, Yulong,Qi, Yan,Yang, Kuiwei
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p. 259 - 266
(2013/12/04)
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- Poly(4-vinylimidazolium) iodides: A highly recyclable organocatalyst precursor for benzoin condensation reaction
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The development of highly efficient, recyclable poly(4-vinylimidazolium) iodides (2) for the benzoin condensation reaction under mild reaction conditions is discussed: poly(4-vinyl N-heterocyclic carbene)s (3) obtained from 2 showed higher catalytic activity than monomeric 4-vinyl N-heterocyclic carbene and could be successfully recovered and reused over seven times without loss of performance. the Partner Organisations 2014.
- Seo, Ue Ryung,Chung, Young Keun
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p. 32371 - 32374
(2014/08/18)
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- NHC-initiated cascade, metal-free synthesis of quinoxaline derivatives under solvent-free conditions
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2,3-Diaryl quinoxaline derivatives have been efficiently synthesized by cascade, metal-free, and solvent-free reaction of aryl aldehydes with aryl 1,2-diamines initiated by N-heterocyclic carbene. Compared with reported methods, this procedure has the advantages of easy work-up, reduced energy consumption, and elimination of solvent waste, hazards, and toxicity. A group of potentially bioactive compounds has been prepared for biomedical screening.
- Gao, Lijiu,Liu, Rui,Yu, Chenxia,Yao, Changsheng,Li, Tuanjie,Xiao, Zhaoxin
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p. 2131 - 2138
(2014/05/06)
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- One-pot asymmetric synthesis of substituted tetrahydrofurans via a multicatalytic benzoin/Michael/acetalization cascade
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A sequential benzoin/Michael/acetalization tandem reaction catalyzed by NHC and amine together has been developed to assemble aromatic aldehydes and enals into chiral tetrahydrofuran derivatives bearing multiple functional groups and stereogenic centers with high stereoselectivity of up to 95:5 dr and 96% ee. The high yield and stereocontrol of this process may be due to both acid-promoted symmetrization of racemic acyloins and iminium ion activation of enals.
- He, Gu,Wu, Fengbo,Huang, Wei,Zhou, Rui,Ouyang, Liang,Han, Bo
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supporting information
p. 2311 - 2319
(2014/07/21)
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- N-Heterocyclic carbene-catalyzed double acylation of enones with benzils
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Thiazolium carbene-catalyzed reaction of aromatic 1,2-diketones with enones in aprotic solvents gave double acylation products in good yields, whereas hydroacylation products formed by Stetter reaction were not detected at all. These results suggested the generation of aroyloxyenamine species from the 1,2-diketones instead of hydroxyenamines (Breslow intermediates). This journal is
- Takaki, Ken,Ohno, Akira,Hino, Makoto,Shitaoka, Takashi,Komeyama, Kimihiro,Yoshida, Hiroto
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supporting information
p. 12285 - 12288
(2014/12/11)
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- Selective reduction of carbonyl groups in the presence of low-valent titanium reagents
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The chemoselective reduction of several structurally diverse compounds containing carbonyl groups was achieved in the presence of low-valent titanium reagents. This novel synthetic method provides easy access to highly selective reduction of carbonyl groups, and possesses several advantages including one-step procedure, convenient manipulation, good to excellent yields, and short reaction times.
- Lin, Wei,Hu, Ming-Hua,Feng, Xian,Fu, Lei,Cao, Cheng-Pao,Huang, Zhi-Bin,Shi, Da-Qing
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p. 2238 - 2242
(2014/04/17)
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- Visible light mediated homo- and heterocoupling of benzyl alcohols and benzyl amines on polycrystalline cadmium sulfide
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The oxidative coupling of sp3 hybridized carbon atoms by photocatalysis is a valuable synthetic method as stoichiometric oxidation reagents can be avoided and dihydrogen is the only byproduct of the reaction. Cadmium sulfide, a readily available semiconductor, was used as a visible light heterogeneous photocatalyst for the oxidative coupling of benzyl alcohols and benzyl amines by irradiation with blue light. Depending on the structure of the starting material, good to excellent yields of homocoupling products were obtained as mixtures of diastereomers. Cross-coupling between benzyl alcohols and benzyl amines gave product mixtures, but was selective for the coupling of tetrahydroisoquinolines to nitromethane. The results demonstrate that CdS is a suitable visible light photocatalyst for oxidative bond formation under anaerobic conditions.
- Mitkina, Tatiana,Stanglmair, Christoph,Setzer, Wolfgang,Gruber, Michael,Kisch, Horst,Koenig, Burkhard
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supporting information; experimental part
p. 3556 - 3561
(2012/06/01)
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- N-heterocyclic carbene-catalyzed annulation of α-cyano-1,4-diketones with ynals
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In this paper, the first stereoselective annulation reaction between r-cyano-1,4-diketones and ynals, mediated by catalytic amounts of a triazolium salt precatalyst and cocatalytic amounts of a weak carboxylate base, is disclosed. The title transformation proceeds smoothly under mild reaction conditions and generates three contiguous stereogenic centers, one of which is a quaternary acetal carbon. This reaction tolerates a wide variety of electronically distinct substituents on both reaction partners and affords privileged bicyclic scaffolds in 61-90% isolated yields and with up to 20:1 diastereomeric preference.
- Romanov-Michailidis, Fedor,Besnard, Celine,Alexakis, Alexandre
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supporting information
p. 4906 - 4909,4
(2012/12/12)
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- N-heterocyclic carbene-catalyzed annulation of α-cyano-1,4-diketones with ynals
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In this paper, the first stereoselective annulation reaction between r-cyano-1,4-diketones and ynals, mediated by catalytic amounts of a triazolium salt precatalyst and cocatalytic amounts of a weak carboxylate base, is disclosed. The title transformation proceeds smoothly under mild reaction conditions and generates three contiguous stereogenic centers, one of which is a quaternary acetal carbon. This reaction tolerates a wide variety of electronically distinct substituents on both reaction partners and affords privileged bicyclic scaffolds in 61-90% isolated yields and with up to 20:1 diastereomeric preference.
- Romanov-Michailidis, Fedor,Besnard, Céline,Alexakis, Alexandre
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supporting information
p. 4906 - 4909
(2013/01/15)
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- One-pot synthesis of quinoxalines starting from aldehydes under metal-free conditions
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An efficient and convenient synthesis of quinoxalines from easily available aldehydes was performed as a one-pot procedure in good to excellent yields under metal-free conditions, via sequential benzoin condensation, aerobic formation of benzils and condensation of the latter with 1,2-diaminobenzenes.
- Hu, Zhong-Yuan,Du, Ding,Tang, Wei-Fang,Lu, Tao
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experimental part
p. 2262 - 2264
(2012/08/07)
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- N-heterocyclic carbene catalyzed one-pot synthesis of 2,3- diarylquinoxalines
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A one-pot efficient and facile protocol for the direct synthesis of quinoxaline derivatives via tandem N-heterocyclic carbene (NHC)-catalyzed umpolung of aldehydes/oxidation of the benzoins to benzils/condensation of benzils with benzene-1,2-diamines has been developed. Georg Thieme Verlag Stuttgart New York.
- Lin, Yang,Lei, Xiaoli,Yang, Qin,Yuan, Jiangjun,Ding, Qiuping,Xu, Jingshi,Peng, Yiyuan
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supporting information
p. 2699 - 2706
(2012/11/13)
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- Synthesis and properties of novel spirobifluorene-cored dendrimers
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Two novel spirobifluorene-cored dendrimers containing polyphenylene dendrons with the carbazole (spiro-Cz) and cyano surface groups (spiro-CN) were synthesized and characterized. Both the dendrimers show good solubility in common organic solvents. Spiro-Cz is amorphous even when it is obtained directly from organic solvents and an extremely high glass transition temperature of 332 °C is detected. These dendrimers can be reversibly oxidized and reduced in electrochemical measurements. They are blue fluorescent with small red-shift in solid film absorption and fluorescence spectra. These advantageous merits are suggested to benefit from the combined contribution from the spirobifluorene core and the bulky polyphenylene dendrons. They were used as emitting layer to fabricate organic light-emitting diodes (OLEDs). Deep-blue electroluminescence was obtained for both dendrimers devices.
- Ren, Huicai,Tao, Qian,Gao, Zhanxian,Liu, Di
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experimental part
p. 136 - 142
(2012/03/27)
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- Synthesis and luminescent properties of perylene bisimide-cored dendrimers with carbazole surface groups
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A group of perylene bisimide (PBI) cored dendrimers were designed and synthesized. The polyphenylene dendrons containing carbazole functional groups at periphery were attached to the PBI core with expectation to control the intermolecular interaction and to tune the charge transporting ability of dendrimers. Their photophysical, electrochemical and thermal properties were investigated. The spectral data showed that energy transfer and photoinduced charge transfer coexist between the carbazole peripheries and the PBI core, competing to influence the luminescent properties of these dendrimers. The red OLEDs were fabricated with these dendrimers as non-doped emitting layer by solution method. The dendrimers bearing carbazoles exhibited improved EL performance than those model compounds. The improved charge balance state caused by these carbazole units is suggested to be responsible for the EL performance.
- Ren, Huicai,Li, Jiuyan,Wang, Renjie,Zhang, Ting,Gao, Zhanxian,Liu, Di
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experimental part
p. 3639 - 3646
(2012/05/20)
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- Synthesis and properties of novel perylenebisimide-cored dendrimers
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A group of perylenebisimide-cored dendrimers with polyphenylene dendrons at four bay positions were synthesized and characterized. The electron-deficient pentafluorophenyl or cyano groups were grafted at the dendrimer surface with the aim to further increase the n-type features of the resulted dendrimers. The electrochemical and optical properties were investigated. All the dendrimers show good solubility and film-forming properties, high EA values of 3.8-3.9 eV, and high fluorescent quantum yields. All these merits indicate that they are potential multifunctional materials for application in optoelectronic devices such as solar cells or organic light-emitting devices.
- Ren, Huicai,Li, Jiuyan,Zhang, Ting,Wang, Renjie,Gao, Zhanxian,Liu, Di
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experimental part
p. 298 - 303
(2012/07/14)
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- An organocatalytic ionic liquid
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The carbene concentration in 1-ethyl-3-methylimidazolium-acetate ionic liquid is sufficiently high to act as a catalyst in benzoin condensation, hydroacylation and also in oxidation of an alcohol by using CO2 and air. This observation reveals the potential of ionic liquid organocatalysts, uniting the beneficial properties of these two families of compounds.
- Kelemen, Zsolt,Holloczki, Oldamur,Nagy, Jozsef,Nyulaszi, Laszlo
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supporting information; experimental part
p. 5362 - 5364
(2011/09/13)
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- NHC triggered cascade metal-free synthesis of 2,3-diarylated indoles under solvent-free conditions
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A new cascade strategy to the synthesis of 2,3-diarylated indoles via the metal-free reaction of aryl aldehyde and aryl amine triggered by N-heterocyclic carbene (NHC) under solvent-free conditions, has been disclosed. The protocol has the advantages of easy work-up, high yields, wide application scope, and an environmentally benign procedure compared with the reported methods.
- Yao, Changsheng,Wang, Donglin,Lu, Jun,Qin, Bingbin,Zhang, Honghong,Li, Tuanjie,Yu, Chenxia
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supporting information; experimental part
p. 6162 - 6165
(2011/11/30)
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- Facile route to benzils from aldehydes via NHC-catalyzed benzoin condensation under metal-free conditions
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A simple and efficient one-pot procedure for the synthesis of α-diketones from aldehydes via benzoin condensation under the influence of a catalytic amount of azolium salt combined with DBU has been developed. Thus, aldehyde was allowed to react with the azolium salt/DBU catalytic system at room temperature, and then the reaction mixture was heated to 70 °C under air atmosphere to afford the corresponding 1,2-diketone in good yield. This would be an efficient alternative method of synthesizing α-diketones from aldehydes under metal-free conditions. Crown Copyright
- Shimakawa, Yuuki,Morikawa, Takashi,Sakaguchi, Satoshi
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supporting information; experimental part
p. 1786 - 1789
(2010/05/19)
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- Synthesis and characterization of a novel benziloxime ligand and its iron(III) and nickel(II) complexes
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The synthesis of a novel benziloxime ligand, 4,4′- dibromobenzilmonoxime (DBBOH) (1) and its complexes [Fe(DBBO)3] (2) and Na[Ni(DBBO)3] (3) are described. The ligand (DBBOH) was prepared in MeOH from the reaction of 4,4′-dibromobenzil with hydroxylamine hydrochloride in the presence of sodium acetate. Reaction of sodium salt of 4,4′-dibromobenzilmonoxime (DBBONa) in MeOH with Fe(NO3) 3.9H2O and Ni(NO3)2.6H2O yielded [Fe(DBBO)3] (2) as yellow and Na[Ni(DBBO)3] (3) as brown precipitates respectively. The ligand, 4,4′-dibromobenzilmonoxime (DBBOH) (1) and its complexes [Fe(DBBO)3] (2) and Na[Ni(DBBO) 3] (3) were characterized by elemental analysis, 1H-NMR and 13C-NMR, IR, and electronic spectral studies. The analysis of IR, 1H-and 13C-NMR spectral data of Fe(III) and Ni(II) complexes suggest that 4,4′-dibromobenzilmonoximate is bonded to iron(III) and nickel(II) ions through the oxygen atom of the carbonyl, and the nitrogen atom of the imine groups. The electronic spectral data of the complexes in CHCl3 are in good agreement with the octahedral coordination of Fe(III) and Ni(II) ions. The ligand field parameters for these complexes, i.e. splitting energy and Racah parameter were calculated to be 21560 cm-1 and 707 cm-1 for [Fe(DBBO)3] (2), 13440 cm-1 and 610 cm-1 forNa[Ni(DBBO)3] (3) respectively.
- Soleimani, Esmaiel
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experimental part
p. 332 - 337
(2011/04/22)
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- Methylene-bridged bis(benzimidazolium) salt as a highly efficient catalyst for the benzoin reaction in aqueous media
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Benzoin reactions are catalyzed effectively by a methylene-bridged bis(benzimidazolium) salt to yield α-hydroxy ketones, and the reactions proceed in water as the aqueous medium under mild conditions. The Royal Society of Chemistry.
- Iwamoto, Ken-Ichi,Kimura, Hitomi,Oike, Masaaki,Sato, Masayuki
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experimental part
p. 912 - 915
(2008/10/09)
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- Microwave assisted benzoin condensation using thiamine as catalyst
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α-Hydroxyketones were prepared in appreciable yields at a very high speed, (by the benzoin condensation) under microwave irradiation using a catalytic amount of thiamine hydrochloride, from various aromatic as well as heteroaromatic aldehydes. They can be used as intermediates in NCE synthesis.
- Bag, Seema,Vaze, Vidula V.,Degani, Mariam S.
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p. 267 - 269
(2007/10/03)
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- 1-Benzhydryl-3-phenylurea and 1-benzhydryl-3-phenylthiourea derivatives: New templates among the CB1 cannabinoid receptor inverse agonists
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New 1-benzhydryl-3-phenylurea derivatives and their 1-benzhydryl-3- phenylthiourea isosteres were synthesized and evaluated for their human CB 1 and CB2 cannabinoid receptor affinity. These compounds proved to be selective CB1 cannabinoid receptor ligands, acting as inverse agonists in a [35S]-GTPγS assay. The affinity of 3,5,5′-triphenylimidazolidine-2,4-dione and 3,5,5′-triphenyl-2- thioxoimidazolidin-4-one derivatives, possessing the 1-benzhydryl-3-phenylurea and 1-benzhydryl-3-phenylthiourea moiety, respectively, was also evaluated. In conclusion, the 1-benzhydryl-3-phenylurea scaffold seems to be a new interesting template of CB1 cannabinoid receptor inverse agonists.
- Muccioli, Giulio G.,Wouters, Johan,Scriba, Gerhard K. E.,Poppitz, Wolfgang,Poupaert, Jacques H.,Lambert, Didier M.
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p. 7486 - 7490
(2007/10/03)
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- Substituted 5,5′-diphenyl-2-thioxoimidazolidin-4-one as CB 1 cannabinoid receptor ligands: Synthesis and pharmacological evaluation
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A set of 30 substituted 5,5′-diphenyl-2-thioxoimidazolidin-4-one (thiohydantoins) derivatives was synthesized, and their affinity for the human CB1 cannabinoid receptor has been evaluated. These compounds are derived from the previously described cannabinoid ligands 5,5′- diphenylimidazolidine-2,4-dione (hydantoins). The replacement of the oxygen by a sulfur leads to an increase of the affinity while the function-i.e., inverse agonism-determined by [35S]-GTPγS experiments remains unaffected. Finally, to evaluate the molecular parameters that could influence the affinity of the thiohydantoins, molecular electrostatic potential as well as lipophilicity calculations were undertaken on representative thiohydantoins and hydantoins derivatives. In conclusion, 5,5′-bis-(4-iodophenyl)-3-butyl-2- thioxoimidazolidin-4-one (31) and 3-allyl-5,5′-bis(4-bromophenyl)-2- thioxoimidazolidin-4-one (32) possess the highest affinity for the CB 1 cannabinoid receptor described to date for the hydantoin and thiohydantoins series when compared in a same bioassay.
- Muccioli, Giulio G.,Martin, Diana,Scriba, Gerhard K. E.,Poppitz, Wolfgang,Poupaert, Jacques H.,Wouters, Johan,Lambert, Didier M.
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p. 2509 - 2517
(2007/10/03)
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- One-step assembly of functionalized γ-butyrolactones from benzoins or benzaldehydes via an N-heterocyclic carbene-mediated tandem reaction
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(Chemical Equation Presented) We describe here a direct, efficient, one-step construction of γ,γ-difunctionalized γ-butyrolactones from benzoins or benzaldehydes via a tandem reaction promoted by 1,3-dimethyl imidazolin-2-ylidene, an N-heterocyclic carbene (NHC).
- Ye, Wei,Cai, Guanliang,Zhuang, Zeyang,Jia, Xueshun,Zhai, Hongbin
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p. 3769 - 3771
(2007/10/03)
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- Versatile access to benzhydryl-phenylureas through an unexpected rearrangement during microwave-enhanced synthesis of hydantoins
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(Equation presented) A new access to benzhydryl-phenylureas is described. These new interesting urea derivatives were obtained by reaction of substituted benzils with substituted phenylureas under microwave irradiation. Phenylthiourea, when reacted with benzil, gave 3-phenyl-thiohydantoin. Moreover, benzylurea, as phenethylurea, gave the corresponding 3-substituted hydantoin derivatives, demonstrating that only phenylurea derivatives can result in benzhydryl-phenylureas under the applied conditions. This new reaction proved to be an easy access to substituted 1-benzhydryl-3-phenyl-ureas.
- Muccioli, Giulio G.,Wouters, Johan,Poupaert, Jacques H.,Norberg, Bernadette,Poppitz, Wolfgang,Scriba, Gerhard K. E.,Lambert, Didier M.
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p. 3599 - 3602
(2007/10/03)
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