- Recyclable Supported Carbene Catalysts for High-Yielding Self-Condensation of Furaldehydes into C10 and C12 Furoins
-
Two highly efficient and recyclable heterogeneous azolium catalyst systems, one grafted (g) onto the inorganic oxide (Silica) and the other onto the organic polymer [Merrifield's peptide or chloromethylated polystyrene (PS) resin], have been developed and employed to catalyze quantitative self-coupling (umpolung condensation) reactions of furfural and 5-hydroxymethylfurfural (HMF) into C10 and C12 furoins, respectively. Supported benzimidazolium ([BI]) salts bearing a long-chain alkyl substituent (i.e.; C12 dodecyl) on the azolium nitrogen atom, upon activation with a suitable base to generate the corresponding N-heterocyclic carbene (NHC) catalyst, are found to be far more effective catalysts for furaldehyde self-coupling reactions than the analogous catalysts carrying a short-chain alkyl substituent (i.e.; C1 methyl). Thus, supported NHC catalysts generated in situ from Silica-g-[BI]-C12 or PS-g-[BI]-C12-benzyl/base afford the C10 and C12 furoins in about 97% and 94% yield, respectively. By adopting a catalyst recycling procedure that involves activation of the precatalyst with a base to generate the NHC catalyst, catalysis in conversion of furaldehydes into furoins, and recycle of the catalyst by quenching the reaction with HCl to convert the catalyst back to the precatalyst, excellent recyclability has been achieved without loss of the catalytic activity after 10 cycles by maintaining essentially a constant furoin yield of 96-97% for all 10 cycles performed with both supported catalyst systems.
- Wang, Lu,Chen, Eugene Y.-X.
-
-
Read Online
- Recyclable montmorillonite-supported thiazolium ionic liquids for high-yielding and solvent-free upgrading of furfural and 5-hydroxymethylfurfural to C10 and C12 furoins
-
Six Na+/montmorillonite (MMT)-supported thiazolium (TM) ionic liquids (ILs), MMT-[TM], which are precatalysts to N-heterocyclic carbene (NHC) catalysts, have been synthesized and employed to catalyze the highly selective condensation of furfural (FF) and 5-hydroxymethylfurfural (HMF) into C10 and C12 furoins, respectively. Among them, five supported [TM] salts carrying the electron-donating group exhibit excellent catalytic activity. Thus, supported NHC catalysts, generated in situ from activation of MMT-[TM] with Et3N, afford C10 and C12 furoins in 97-99% and 97-98% yield, respectively. This condensation reaction is also carried out under solvent-free conditions, and the catalysts can be readily recycled, showing no noticeable loss in their catalytic activity over four consecutive recycles. Thus, these desired features possessed by the current catalyst system have enabled the development of the greener and more environmentally benign process for the upgrading of FF and HMF.
- Yan, Bing,Zang, Hongjun,Jiang, Yi,Yu, Songbai,Chen, Eugene Y.-X.
-
-
Read Online
- Hybrid catalysts based on N-heterocyclic carbene anchored on hierarchical zeolites
-
Hybrid materials have been synthesized by anchoring a N-heterocyclic carbene (NHC) precursor on different inorganic zeolitic supports with hierarchical porosity, in particular hierarchical HZSM-5 and SAPO-5. Hierarchical porous inorganic supports have been obtained both by top-down and bottom-up approaches and the role of hierarchical porosity has been evaluated. A detailed physico-chemical characterization has been performed on the organic-inorganic hybrids using a multi-technique approach (XRD, volumetric and thermogravimetric analysis, ssNMR and FTIR) in order to establish a structure-property relationship. The hybrids were tested in the benzoin condensation reaction of furfural, a base catalyzed reaction.
- Gianotti, Enrica,Miletto, Ivana,Ivaldi, Chiara,Paul, Geo,Marchese, Leonardo,Meazza, Marta,Rios, Ramon,Raja, Robert
-
-
Read Online
- Total Synthesis of (+)-Hyacinthacine A1Using a Chemoselective Cross-Benzoin Reaction and a Furan Photooxygenation-Amine Cyclization Strategy
-
We report the shortest synthesis of glycosidase inhibitor (+)-hyacinthacine A1 using a highly chemoselective N-heterocyclic carbene-catalyzed cross-benzoin reaction as well as a furan photooxygenation-amine cyclization strategy. This is the first such cyclization on a furylic alcohol, an unprecedented reaction due to the notorious instability of the formed intermediates. The photooxygenation strategy was eventually incorporated into a three-step one-pot process that formed the requisite pyrrolizidine framework of (+)-hyacinthacine A1.
- Parmar, Karnjit,Haghshenas, Pouyan,Gravel, Michel
-
supporting information
p. 1416 - 1421
(2021/02/20)
-
- N-PEGylated Thiazolium Salt: A Green and Reusable Homogenous Organocatalyst for the Synthesis of Benzoins and Acyloins
-
N-PEGylated-thiazolium salt is used as efficient catalyst for the benzoin condensation. The catalyst was synthesized by reaction of activated polyethylene glycol 10,000 (PEG-10000) with 4-methyl-5-thiazoleethanol (sulfurol). Reaction mixture undergoes temperature-assisted phase transition and catalyst separated by simple filtration. After reaction course, catalyst can be recycled and reused without any apparent loss of activity which makes this process cost effective and hence ecofriendly. Synthesized benzoins and acyloins by this method have been characterized on the basis of melting point and 1H-NMR spectral studies. Graphic Abstract: [Figure not available: see fulltext.]
- Haghighi, Ali Javaheri,Mokhtari, Javad,Karimian, Khashayar
-
p. 1646 - 1652
(2020/10/19)
-
- Synthesis of 1,10-decanediol diacetate and 1-decanol acetate from furfural
-
A green and efficient method was developed for upgrading furfural to 1,10-decanediol diacetate and 1-decanol acetate. 92% yield of the acetates was obtained through the tandem benzoin condensation and hydrodeoxygenation reaction. During the benzoin condensation, furfural was catalyzed into furoin in a quantitative yield by the immobilized NHC catalyst under solvent-free conditions. After dissolving the furoin intermediate in acetic acid, the Sc(OTf)3and Pd/C catalytic system was introduced for hydrodeoxygenation. The effects of reaction factors have been investigated in detail and the hydrodeoxygenation process has been explored by1H-NMR and GC-MS.
- Deng, Chen-Qiang,Jiang, Qin-Zhu,Deng, Jin,Fu, Yao
-
supporting information
p. 2169 - 2176
(2021/03/26)
-
- Sol-gel synthesis of ceria-zirconia-based high-entropy oxides as high-promotion catalysts for the synthesis of 1,2-diketones from aldehyde
-
Efficient Lewis-acid-catalyzed direct conversion of aldehydes to 1,2-diketones in the liquid phase was enabled by using newly designed and developed ceria–zirconia-based high-entropy oxides (HEOs) as the actual catalysts. The synergistic effect of various cations incorporated in the same oxide structure (framework) was partially responsible for the efficiency of multicationic materials compared to the corresponding single-cation oxide forms. Furthermore, a clear, linear relationship between the Lewis acidity and the catalytic activity of the HEOs was observed. Due to the developed strategy, exclusively diketone-selective, recyclable, versatile heterogeneous catalytic transformation of aldehydes can be realized under mild reaction conditions.
- Dinjar, Kristijan,Djerdj, Igor,Koj?inovi?, Jelena,Kukovecz, ákos,Markovi?, Berislav,Mileti?, Aleksandar,Nagy, Sándor Balázs,Sapi, Andras,Stenzel, David,Széchenyi, Aleksandar,Szenti, Imre,Tang, Yushu,Tatar, Dalibor,Varga, Gábor,Ziegenheim, Szilveszter
-
-
- Method for preparing sebacic acid ester and derivatives thereof (by machine translation)
-
. Uses the compound of the formula, as the raw material, in the acid solvent selective hydrodeoxygenation to obtain.decanediol and n-decanol: and the method (I) is characterized in that the product is cheap and easily available, product in yield, high in purity, and suitable for industrial production 1,10 - in a simple, process route . The product obtained by the method has the advantages of high yield, high yield and low pollution, to the environment, and the corresponding alcohol, is obtained by saponification reaction. (by machine translation)
- -
-
Paragraph 0064-0072
(2020/05/01)
-
- Oxazolium Salts as Organocatalysts for the Umpolung of Aldehydes
-
Oxazolium salts were successfully employed for the first time as organocatalysts for benzoin, Stetter, and redox esterification reactions. An N-mesityl oxazolium salt catalyzed homobenzoin reaction of aromatic, heteroaromatic, and aliphatic aldehydes delivered α-hydroxy ketones in high yields. This new type of catalyst proved remarkably effective for the Stetter reaction of challenging substrates such as β-alkyl-α,β-unsaturated ketones and electron-rich aromatic aldehydes in comparison to common thiazolium and triazolium salts.
- Garapati, Venkata Krishna Rao,Gravel, Michel
-
supporting information
p. 6372 - 6375
(2018/10/15)
-
- Thiazole ionic liquid catalysis of furfural coupling into furoin
-
Furfural is an important platform compound and is a precursor for preparation of biology liquid fuel and many other important fine chemical products. However, furfural is mainly prepared by dehydration of C5 sugar. Though furfural is latent fuel for means of transportation, furfural is alkane with low carbon number and has characteristics of high fluctuation and low energy density. Thus, furfuralcannot become an ideal fuel additive. According to the invention, without a solvent, a thiazole ionic liquid with anions as weak acid radicals is utilized for catalysis of furfural coupling into furoin. Usually, an ionic liquid has the property of catalyzing furfural coupling into furoin only with the addition of alkali. As anions of the ionic liquid used in the reaction are weak acid radicals, the ionic liquid with weak acid radicals can complete catalytic action of the furfural coupling reaction and can achieve an ideal catalytic effect.
- -
-
Paragraph 0016; 0017; 0018; 0019; 0020; 0021; 0022-0027
(2018/03/24)
-
- Difuran-substituted quinoxalines as a novel class of PI3Kα H1047R mutant inhibitors: Synthesis, biological evaluation and structure-activity relationship
-
Phosphatidylinositol 3-kinase α (PI3Kα) is the most frequently mutated kinase in human cancers, making it an attractive therapeutic target for cancer treatment. We identified a structurally novel PI3Kα H1047R mutant inhibitor Hit-01 (EC50 = 76.0 μM) through a high-throughput screening campaign. Chemical optimizations enabled us to discover compound 7b, which strongly inhibited PI3Kα H1047R mutant with an EC50 value of 0.137 μM, over 500-fold more potent than Hit-01. Western blotting analysis suggested that 7b could decrease the phosphorylation level of p-AKT, another proof that 7b inhibited PI3Kα H1047R function. Cell viability assay revealed that 7b inhibited HCT116 cancer cell growth with an IC50 value of 11.23 μM. In addition, 7b was found to arrest cell cycle at G1 phase and induce cell apoptosis via up-regulation of caspase-3, caspase-8 and caspase-9 protein expressions. Collectively, all these data demonstrated that 7b could be a promising lead for the development of structurally novel PI3Kα inhibitors.
- Zhang, Ning,Yu, Zhimei,Yang, Xiaohong,Zhou, Yan,Tang, Qing,Hu, Ping,Wang, Jia,Zhang, Shao-Lin,Wang, Ming-Wei,He, Yun
-
-
- COMPOUNDS AND USES THEREOF IN THE TREATMENT OF CANCERS AND OTHER MEDICAL CONDITIONS
-
There are provided compounds, their preparation and their use in the treatment of medical conditions including cancers and immune disorders.
- -
-
Paragraph 0101; 0103; 0118; 00128
(2017/02/09)
-
- CO2-assisted synthesis of non-symmetric α-diketones directly from aldehydes: Via C-C bond formation
-
CO2-assisted various symmetric and non-symmetric α-diketones have been synthesized directly from the corresponding aldehydes using transition metal-free catalysts. This method can even be applied to synthesize pharmaceuticals directly from aldehydes. The crucial role of CO2 has been investigated in detail and the mechanism is proposed on the basis of experiments and DFT calculations.
- Hirapara, Pradipbhai,Riemer, Daniel,Hazra, Nabanita,Gajera, Jignesh,Finger, Markus,Das, Shoubhik
-
supporting information
p. 5356 - 5360
(2017/11/22)
-
- Chemo- and Diastereoselective N-Heterocyclic Carbene-Catalyzed Cross-Benzoin Reactions Using N-Boc-α-amino Aldehydes
-
N-Boc-α-amino aldehydes are shown to be excellent partners in cross-benzoin reactions with aliphatic or heteroaromatic aldehydes. The chemoselectivity of the reaction and the facial selectivity on the amino aldehyde allow cross-benzoin products to be obtained in good yields and good diastereomeric ratios. The developed method is utilized as the key step in a concise total synthesis of d-arabino-phytosphingosine.
- Haghshenas, Pouyan,Gravel, Michel
-
p. 4518 - 4521
(2016/09/28)
-
- SUPPORTED CATALYST FOR ALDEHYDE COUPLING REACTION, METHOD FOR PERFORMING ALDEHYDE COUPLING REACTION, AND METHOD FOR REGENERATING SUPPORTED CATALYST FOR ALDEHYDE COUPLING REACTION
-
A supported catalyst for aldehyde coupling reaction, comprising a carrier having supported thereon a catalyst comprising at least one azolium compound selected from the group consisting of a thiazolium salt, an imidazolium salt, a benzimidazolium salt and a triazolium salt, the azolium compound having, at a nitrogen atom thereof, a substituent selected from the group consisting of an aliphatic group having 6 or more carbon atoms and an aromatic group having 6 or more carbon atoms.
- -
-
Paragraph 0020
(2016/12/22)
-
- Synthesis and biological evaluation of novel 1,2,4-triazine derivatives bearing carbazole moiety as potent α-glucosidase inhibitors
-
A new series of 1,2,4-triazine derivatives bearing carbazole moiety 7a-7p were designed, synthesized, and evaluated for their α-glucosidase inhibitory activity. The majority of the screened compounds displayed potent α-glucosidase inhibitory activity, with IC50 values in the range of 4.27 ± 0.07-47.75 ± 0.25 μM as compared to the standard drug acarbose. Among the series, compound 7k represented the most potent α-glucosidase inhibitory activity with IC50 values of 4.27 ± 0.07 μM. Kinetic analysis revealed that compound 7k is a non-competitive inhibitor with a Ki of 4.43 μM. Furthermore, the binding interactions of compound 7k with α-glucosidase was confirmed through molecular docking. This study showed these 1,2,4-triazine derivatives bearing carbazole moiety as a new class of α-glucosidase inhibitors.
- Wang, Guangcheng,Wang, Jing,He, Dianxiong,Li, Xin,Li, Juan,Peng, Zhiyun
-
p. 2806 - 2809
(2016/06/09)
-
- An interchangeable homogeneous ? heterogeneous catalyst system for furfural upgrading
-
Intercalation of benzimidazolium cations [BI]+ into the nanogalleries of Na+/montmorillonite (MMT) clay leads to generation of recyclable supported precatalysts [BI]+/MMT, which, upon treatment with a base, catalyze furfural self-condensation coupling reaction into furoin in almost constant yields of >96% over the three cycles investigated. This catalyst system combines the best features of both homogeneous and heterogeneous catalyst systems, as it performs the homogeneous molecular catalysis by the discharged N-heterocyclic carbene catalyst in solution and then recovers the catalyst through in situ heterogenization after the reaction via re-intercalation of the charged precatalyst. The [12,12BI]+/MMT catalyst system carrying two long-chain C12 dodecyl substituents on the [BI] nitrogen atoms is particularly effective for achieving both high product yield and catalyst recyclability.
- Wang, Lu,Chen, Eugene Y.-X.
-
supporting information
p. 5149 - 5153
(2015/12/05)
-
- Cocamidopropyl betaine catalyzed benzoin condensation and pseudo-four-component reaction of the in situ formed benzoin in water
-
An improved synthesis of benzoins, as key synthetic building blocks, and substituted pyrroles in micelle medium using a very small amount of cocamidopropyl betaine in water is described. In this one-pot strategy, benzoin condensation of aldehydes and further pseudo-four-component reaction of the in situ formed benzoin with 1,3-dicarbonyls, and ammonium acetate gave excellent yields of the desired pyrrole products.
- Tamaddon, Fatemeh,Alizadeh, Masoomeh
-
p. 525 - 530
(2015/04/14)
-
- Synthesis of functionalized γ-lactones via a three-component cascade reaction catalyzed by consecutive N-heterocyclic carbene systems
-
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
-
p. 26972 - 26976
(2015/03/30)
-
- The synthesis of new donor-acceptor polymers containing the 2,3-di(2-furyl) quinoxaline moiety: Fast-switching, low-band-gap, p- and n-dopable, neutral green-colored materials
-
Three donor-acceptor type π-conjugated polymers were synthesized electrochemically:poly[2,3-di(2-furyl)-5,8-bis(2-(3,4-ethylenedioxythiophene)) quinoxaline] (PFETQ), poly[2,3-di(2-furyl)-5,8-bis(2-thienyl) quinoxaline] (PFTQ) and poly[2,3-di(2-furyl)-5,8-bis(2-(3-methoxythiophene)) quinoxaline] (PFMTQ). All of the synthesized polymers, contained the 2,3-di(2-furyl) quinoxaline moiety in the backbone as the acceptor unit and different thiophene derivatives as the donor units. The electroactivity of the monomers and the electrochemical properties of their polymers were investigated by cyclic voltammetry. The presence of the strong electron-donating ethylenedioxy and methoxy groups on the aromatic structure increased the electron density. Thus, the oxidation potential of FETQ and FMTQ shifted to a lower value than that of FTQ. The optical properties of the polymers were investigated by UV-vis-NIR spectroscopy. Both PFETQ and PFMTQ reveal two distinct absorption bands in the red and blue regions of the visible spectrum, while PFTQ has only one dominant wavelength at 596 nm in the visible region. The colorimetry analysis revealed that while PFTQ has a light blue color, PFETQ and PFMTQ are green in the neutral state. The optical band gaps, defined as the onset of the π-π? transition, were found to be 1.15 eV for PFETQ, 1.2 eV for PFMTQ and 1.34 eV for PFTQ. Moreover, all three polymers showed both n-doping and fast switching times.
- Xu, Zhen,Wang, Min,Fan, Weiyu,Zhao, Jinsheng,Wang, Huaisheng
-
p. 271 - 280
(2015/03/04)
-
- Chemiluminescence determination of human serum albumin based on Co2+-catalyzed 2-(4-tert-butylphenyl)-4,5-di(2-furyl) imidazole/H2O2 system
-
In this paper, the chemiluminescence (CL) reaction of 2-(4-tert-butylphenyl)-4,5-di(2-furyl) imidazole (t-BDFI) and H2O2 was investigated in alkaline medium. The H2O2 could directly oxidize t-BDFI to produce CL emission. The effects of some metal ions on CL of the t-BDFI/H2O2 system were examined. The results indicated that the addition of Co2+ into the t-BDFI/H2O2 CL system could induce significant enhancement of the CL signal. A CL system of t-BDFI/H2O2/Co2+ was developed. The experiment on the effect of human serum albumin (HSA) on the t-BDFI/H2O2/Co2+ CL system was carried out, and the result indicated that HSA could effectively inhibit the CL signal of this reaction. The inhibited CL intensity is linearly related to the logarithm of concentration of HSA. The linear range of the calibration curve is 5.0 × 10-8 to 1.0 × 10-6 mol L-1, and the corresponding detection limit (3σ) is 2.1 × 10-8 mol L-1. Based on this study, a novel CL method has been developed for the determination of HSA with high sensitivity and good selectivity. The proposed method has been successfully applied to the determination of HSA in human serum samples. This may intrigue researchers into gaining a new interest in investigating the CL property of heterocyclic imidazole derivatives.
- Kang, Jing,Shen, Jimin,Chen, Zhonglin,Nan, Jun,Huang, Xiao,Han, Lu,Hao, Weiping
-
p. 89569 - 89576
(2015/11/10)
-
- Upgrading biogenic furans: Blended C10-C12 platform chemicals via lyase-catalyzed carboligations and formation of novel C12 - Choline chloride-based deep-eutectic-solvents
-
Benzaldehyde lyase (BAL) results in an efficient biocatalyst for the umpolung carboligation of furfural, HMF, and mixtures of them, leading to blended C10-C12 platform chemicals. Subsequently, the mixing and gentle heating (100°C) of the formed hydroxy-ketone with choline chloride leads to the formation of a novel biomass-derived deep-eutectic-solvent.
- Donnelly, Joseph,Müller, Christoph R.,Wiermans, Lotte,Chuck, Christopher J.,Domínguez De María, Pablo
-
p. 2714 - 2718
(2015/05/27)
-
- Bis(amino)cyclopropenylidene (BAC) catalyzed aza-benzoin reaction
-
A bis(amino)cyclopropenylidene (BAC) catalyzed aza-benzoin reaction between aldehydes and phosphinoyl imines has been developed. The reaction is general with a wide range of aromatic aldehydes and aromatic imines. The reaction displays excellent chemoselectivity favoring aza-benzoin products over homobenzoin products. (Chemical Equation Presented).
- Wilde, Myron M. D.,Gravel, Michel
-
supporting information
p. 5308 - 5311
(2015/02/19)
-
- Chemoselective N-heterocyclic carbene-catalyzed cross-benzoin reactions: Importance of the fused ring in triazolium salts
-
Morpholinone- and piperidinone-derived triazolium salts are shown to catalyze highly chemoselective cross-benzoin reactions between aliphatic and aromatic aldehydes. The reaction scope includes ortho-, meta-, and para-substituted benzaldehyde derivatives with a range of electron-donating and -withdrawing groups as well as branched and unbranched aliphatic aldehydes. Catalytic loadings as low as 5 mol % give excellent yields in these reactions (up to 99%).
- Langdon, Steven M.,Wilde, Myron M.D.,Thai, Karen,Gravel, Michel
-
supporting information
p. 7539 - 7542
(2014/06/10)
-
- BIOREFINING COMPOUNDS AND ORGANOCATALYTIC UPGRADING METHODS
-
The invention provides new methods for the direct umpolung self-condensation of 5-hydroxymethylfurfural (HMF) by organocatalysis, thereby upgrading the readily available substrate into 5,5'-di(hydroxymethyl) furoin (DHMF). While many efficient catalyst systems have been developed for conversion of plant biomass resources into HMF, the invention now provides methods to convert such nonfood biomass directly into DHMF by a simple process as described herein. The invention also provides highly effective new methods for upgrading other biomass furaldehydes and related compound to liquid fuels. The methods include the organocatalytic self-condensation (umpolung) of biomass furaldehydes into (C8-C12)furoin intermediates, followed by hydrogenation, etherification or esterification into oxygenated biodiesel, or hydrodeoxygenation by metal-acid tandem catalysis into premium hydrocarbon fuels.
- -
-
Page/Page column 30; 35
(2014/01/18)
-
- From Furfural to Fuel: Synthesis of Furoins by Organocatalysis and their Hydrodeoxygenation by Cascade Catalysis
-
The synthesis of furoins from biomass-derived furfural and 2-methylfurfural is demonstrated in high yields in green and renewable solvents using N-heterocyclic carbene organocatalysts. The resulting furoin molecules are used as precursors for fuels using cascade catalysis, first by using Pd/C with acidic co-catalysts under very mild conditions to yield oxygenated C12molecules. Two main products were formed, which we identified as 1,2-bis(5-methyltetrahydrofuran-2-yl)ethane and 1-(5-methyltetrahydrofuran-2-yl)heptanol. The use of a Pd/Zeolite-β catalyst under more extreme conditions resulted in the complete hydrodeoxygenation of 5,5′-dimethylfuroin to dodecanes in high yields (76 %) and exceptional selectivity (94 %) for n-dodecane.
- Wegenhart, Benjamin L.,Yang, Linan,Kwan, Soon Cheong,Harris, Remi,Kentt?maa, Hilkka I.,Abu-Omar, Mahdi M.
-
p. 2742 - 2747
(2016/12/23)
-
- Synthesis of new chiral keto alcohols by baker's yeast
-
Fourteen chiral α- and β-keto alcohols 2a-2r were synthesized by the asymmetric reduction of their corresponding diketones 1a-1r via baker's yeast. In addition, ten corresponding racemic α-keto alcohols were synthesized by the benzoin condensation of their corresponding aldehydes, which were used for the determination of the ee values through their chiral resolution on chiral HPLC. Amongst the 15 diketones, 1j and chiral α-keto alcohols 2i, 2j and chiral β-keto alcohol 2r are novel compounds. Six keto alcohols 2b, 2c, 2d, 2f, 2h and 2p were synthesized by baker's yeast for the first time. There are some studies in the literature where baker's yeast was applied to the diketones 1a, 1g, 1e, 1k and 1n under various conditions different to those reported herein. The yields and the ee values of these studies were not as high as ours. All of the keto alcohols synthesized were characterized by IR, NMR (1H and 13C), and MS. The relationship between the structure of the diketone and the yield, diastereoselectivity and enantiomeric excess is also discussed.
- Yildiz, Tuelay,Canta, Nurguel,Yusufoglu, Ayse
-
p. 340 - 347
(2014/04/03)
-
- One-pot asymmetric synthesis of substituted tetrahydrofurans via a multicatalytic benzoin/Michael/acetalization cascade
-
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
-
supporting information
p. 2311 - 2319
(2014/07/21)
-
- Two structurally analogous ruthenium complexes as naked-eye and reversible molecular "light switch" for G-quadruplex DNA
-
A pair of symmetrical furyl based ruthenium(II) complexes ([Ru(phen) 2dpq-df]2 + (1) and [Ru(bpy)2dpq-df] 2 + (2) (phen = 1,10-phenanthroline, bpy = 2,2′-bipyridine, dpq-df = dipyrido (3,2-a:2′,3′-c) quinoxaline-difuran) have been prepared and characterized. The binding properties of both complexes toward G-quadruplex DNA have been investigated by fluorescence spectroscopy, UV-Vis spectroscopy, circular dichroism (CD), fluorescence resonance energy transfer (FRET) melting assays and molecular docking studies. The experimental results indicated that both Ru-complexes exhibited a remarkable "light switch" effect in the presence of hybrid G-quadruplex DNA. Interestingly, the "light switch" can be repeated off and on through the successive addition of Cu2 + ions and EDTA, and all these behaviors can be observed even by the naked eyes. Moreover, FRET melting assay revealed that both complexes could be potential stabilizers for G-quadruplex architectures. The computational studies not only confirmed that the two complex molecules bound to one G-quadruplex DNA molecule, but also explained the "light switch" effect.
- Lu, Xiao-Hui,Shi, Shuo,Yao, Jun-Liang,Gao, Xing,Huang, Hai-Liang,Yao, Tian-Ming
-
-
- Effects of alkyl or alkoxy side chains on the electrochromic properties of four ambipolar donor-acceptor type polymers
-
Four donor-acceptor type π-conjugated polymers, poly[2,3-di(2-furyl)-5,8-bis(2-(4-butoxythiophene))quinoxaline] (PFBOTQ), poly[2,3-di(5-methylfuran-2-yl)-5,8-bis(2-(4-butoxythiophene))quinoxaline] (PMFBOTQ), poly[2,3-di(2-furyl)-5,8-bis(2-(4-butylthiophene))quinoxaline] (PFBTQ) and poly[2,3-di(5-methylfuran-2-yl)-5,8-bis(2-(4-butylthiophene))quinoxaline] (PMFBTQ) containing 2,3-di(2-furyl)quinoxaline or 2,3-di(5-methylfuran-2-yl)quinoxaline moiety in the backbone as the acceptor unit and different thiophene derivatives as donor units are synthesized electrochemically. The four polymers are characterized by cyclic voltammetry (CV), UV-Vis-NIR spectroscopy, scanning electron microscopy (SEM) and step profiler. Both PFBOTQ and PMFBOTQ with strong electron-donating butoxy groups have lower oxidation potentials than PFBTQ and PMFBTQ, respectively. Electrochemical measurements and spectroelectrochemistry analyses demonstrate that all four polymers exhibit both p- and n-type doping processes. Both PFBOTQ and PMFBOTQ exhibit a green color in the neutral state, whereas PFBTQ with two absorption bands at 349 nm and 541 nm shows a light purplish red color and PMFBTQ with one obvious absorption band at 349 nm, as well as a shoulder peak located at around 500 nm shows a light brown-red color in the neutral state. Furthermore, as typical donor-acceptor polymers, all four polymers present robust stabilities, low optical band gaps, excellent optical contrasts in the NIR region, satisfactory coloration efficiencies and fast switching times, which make these four polymers outstanding candidates for electrochromic applications.
- Liu, Yanxia,Wang, Min,Zhao, Jinsheng,Cui, Chuansheng,Liu, Jifeng
-
p. 52712 - 52726
(2015/02/18)
-
- 2,2'-FUROIN DERIVATIVES AND USE THEREOF TO LIGHT SKIN
-
The invention relates to the use of compounds of the formula (I), in which R1, R2, m and n have the meanings indicated in the Claims, and/or physiologically acceptable salts, tautomers, stereoisomers and/or solvates thereof, including mixtures thereof in all ratios, for the inhibition of tyrosinase and for lightening the skin. The invention also relates to the use of the compounds of the formula (I) in the prophylaxis, therapy or progress control of pigment disorders of the skin. The invention furthermore relates to preparations comprising the compounds of the formula (I) in combination with at least one further active compound and to a process for the preparation of the preparations by mixing the compounds of the formula (I) with a vehicle which is physiologically acceptable for topical applications.
- -
-
Paragraph 0241
(2013/07/05)
-
- The catalytic versatility of low toxicity dialkyltriazolium salts: In situ modification facilitates diametrically opposed catalysis modes in one pot
-
The ability of triazolium salts to serve as a precatalyst for both an acid and a powerful base/nucleophile (controlled by additives) has been exploited in a process characterised by a unique in situ catalyst modification strategy. The Royal Society of Chemistry 2013.
- Myles, Lauren,Gathergood, Nicholas,Connon, Stephen J.
-
supporting information
p. 5316 - 5318
(2013/06/27)
-
- Thiazolium-functionalized polystyrene monolithic microreactors for continuous-flow umpolung catalysis
-
Thiazolium salt pre-catalysts have been immobilized on silica and monolithic polystyrene and their activity was tested under batch conditions in three model umpolung reactions, namely the benzoin condensation of benzaldehyde, the acyloin-type condensation of biacetyl, and the Stetter reaction of biacetyl with trans-chalcone. A prerequisite of the study has been the utilization of environmentally benign water and ethanol solvents. After having established the higher performance of polystyrene monolithic thiazolium carbene catalysts, their effectiveness has been tested under the flow regime by fabricating the corresponding monolithic microreactors (pressure-resistant stainless-steel columns). Importantly, it has been demonstrated by a brief substrate scope study that the polymeric matrix and the continuous flow regime synergistically contribute to preserve the activity of the carbene catalysts over time, thus permitting the long-term operation (up to 7 days) of the prepared monolithic reactors for the production of valuable compounds via the umpolung strategy.
- Bortolini, Olga,Cavazzini, Alberto,Dambruoso, Paolo,Giovannini, Pier Paolo,Caciolli, Lorenzo,Massi, Alessandro,Pacifico, Salvatore,Ragno, Daniele
-
p. 2981 - 2992
(2013/10/08)
-
- One-pot synthesis of quinoxalines starting from aldehydes under metal-free conditions
-
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
-
experimental part
p. 2262 - 2264
(2012/08/07)
-
- N-heterocyclic carbene catalyzed one-pot synthesis of 2,3- diarylquinoxalines
-
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
-
supporting information
p. 2699 - 2706
(2012/11/13)
-
- Determination Co2+ in vitamin B12 based on enhancement of 2-(4-substituted-phenyl)-4,5-di(2-furyl) imidazole and H 2O2 chemiluminescence reaction
-
In this paper, three kinds of imidazole derivatives, 2-(4-methylphenyl)-4, 5-di(2-furyl) imidazole (MDFI), 2-(4-nitrophenyl)-4,5-di(2-furyl) imidazole (NDFI), and 2-(4-tert-butylphenyl)-4,5-di(2-furyl) imidazole (t-BDFI) were synthesized. In an alkaline medium, the chemiluminescence (CL) reaction of imidazole derivatives with H2O2 has been investigated. It was also found that MDFI/H2O2 and t-BDFI/H 2O2 systems gave strong CL. When Co2+ was added into the two CL systems, the CL intensity was remarkably enhanced. In the optimum conditions, the CL intensity is linearly related to the logarithm of concentration of Co2+. The linear ranges are 5 × 10 -9-2.5 × 10-7 mol/L for MDFI/H2O 2 system and 5 × 10-9-2.5 × 10-7 mol/L for t-BDFI/H2O2 system, and the corresponding detection limits are 1.2 × 10-9 mol/L and 1.1 × 10 -9 mol/L, respectively. The method was applied to the determination of Co2+ in vitamin B12 injection. Furthermore, the CL mechanism was also discussed.
- Han, Lu,Zhang, Yumin,Kang, Jing,Tang, Jieli,Zhang, Yihua
-
scheme or table
p. 146 - 152
(2011/11/12)
-
- Synthesis of thermoregulated phase-separable triazolium ionic liquids catalysts and application for Stetter reaction
-
A series of polyether-substituted triazolium ionic liquids catalysts have been first synthesized for resolving the problem of separation and reuse of Stetter catalysts. The catalysts possess the properties of critical solution temperature (CST) and inverse temperature-dependent solubility in toluene/heptane solvents. Based on these properties, the catalysts can achieve the catalytic process named as thermoregulated phase-separable catalysis (TPSC) with the characteristic of homogeneous reaction at higher temperature and phase-separation at lower temperature. The novel TPSC system has been successfully applied for Stetter reaction of furfural or butanal with ethyl acrylate. The experimental results have showed that the novel catalysts exhibit excellent TPSC with high recycling efficiency.
- Yu, Feng-Li,Zhang, Rui-Li,Xie, Cong-Xia,Yu, Shi-Tao
-
experimental part
p. 9145 - 9150
(2011/01/12)
-
- Polyether-substituted thiazolium ionic liquid catalysts - A thermoregulated phase-separable catalysis system for the Stetter reaction
-
A series of polyether-substituted thiazolium ionic liquids have been synthesized and used as catalysts in the Stetter reaction. The ionic liquids are a thermoregulated phase-separable catalysis (TPSC) system, because they possess the properties of critical solution temperature (CST) and inverse temperature-dependent solubility in toluene-heptane. The results showed that the novel TPSC system exhibits high recycling efficiency, and provides a potential route for a environmentally benign Stetter reaction. The Royal Society of Chemistry 2010.
- Yu, Fengli,Zhang, Ruili,Xie, Congxia,Yu, Shitao
-
experimental part
p. 1196 - 1200
(2010/10/20)
-
- Facile route to benzils from aldehydes via NHC-catalyzed benzoin condensation under metal-free conditions
-
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
-
supporting information; experimental part
p. 1786 - 1789
(2010/05/19)
-
- Finding furfural hydrogenation catalysts via predictive modelling
-
We combine multicomponent reactions, catalytic performance studies and predictive modelling to find transfer hydrogenation catalysts. An initial set of 18 ruthenium-carbene complexes were synthesized and screened in the transfer hydrogenation of furfural to furfurol with isopropyl alcohol complexes gave varied yields, from 62% up to >99.9%, with no obvious structure/activity correlations. Control experiments proved that the carbene ligand remains coordinated to the ruthenium centre throughout the reaction. Deuterium-labelling studies showed a secondary isotope effect (kH:kD = 1.5). Further mechanistic studies showed that this transfer hydrogenation follows the so-called monohydride pathway. Using these data, we built a predictive model for 13 of the catalysts, based on 2D and 3D molecular descriptors. We tested and validated the model using the remaining five catalysts (cross-validation, R2 = 0.913). Then, with this model, the conversion and selectivity were predicted for four completely new ruthenium-carbene complexes. These four catalysts were then synthesized and tested. The results were within 3% of the model's predictions, demonstrating the validity and value of predictive modelling in catalyst optimization.
- Strassberger, Zea,Mooijman, Maurice,Ruijter, Eelco,Alberts, Albert H.,Maldonado, Ana G.,Orru, Romano V. A.,Rothenberg, Gadi
-
experimental part
p. 2201 - 2210
(2010/11/05)
-
- A facile route to ruthenium-carbene complexes and their application in furfural hydrogenation
-
A number of new N-heterocyclic carbene (NHC) ligands were synthesized via a multicomponent reaction, wherein an aldehyde or ketone, a primary amine and an a-acidic isocyanide were reacted, giving the corresponding 2H-2-imidazolines. These were easily alkylated with an alkyl halide at position N-3, yielding the final NHC precursors, that were then complexed with Ru in situ. The resulting complexes are shown to be active and selective catalysts for the transfer hydrogenation of furfural to furfurol, using isopropanol as the hydrogen source. Importantly, the carbene ligand remains coordinated to the ruthenium center throughout the reaction. Copyright
- Strassberger, Zea,Mooijman, Maurice,Ruijter, Eelco,Alberts, Albert H.,De Graaff, Corien,Orru, Romano V.A.,Rothenberg, Gadi
-
experimental part
p. 142 - 146
(2010/11/19)
-
- Study on the reactivity of aldehydes in electrolyzed ionic liquids: Benzoin condensation - Volatile organic compounds (VOCs) vs. room temperature ionic liquids (RTILs)
-
The benzoin condensation of aromatic and heteroaromatic aldehydes, catalyzed by electrochemically generated N-heterocyclic carbenes, has been set up in the absence of organic solvents and bases. α-Hydroxy ketones have been isolated in good to elevated yields, in short reaction times. Aldol products and carbene-aldehyde adducts have been obtained in elevated yields from linear and short branched aldehydes, respectively. A comparison with the use of classical organic solvents has been reported Copyright
- Chiarotto,Feroci,Orsini,Feeney,Inesi
-
supporting information; experimental part
p. 3287 - 3292
(2011/02/23)
-
- Thiazolium-tethering rotaxane-catalyzed asymmetric benzoin condensation: Unique asymmetric field constructed by the cooperation of rotaxane components
-
Asymmetric benzoin condensation of aromatic aldehydes with two kinds of optically active rotaxanes possessing thiazolium salt moieties was studied. A binaphthyl group as the chiral auxiliary was introduced in either the wheel or the axle component of the rotaxanes. Rate of the catalytic benzoin condensation of benzaldehyde with a rotaxane catalyst without the binaphthyl moiety was compared with its axle component to understand the effect of wheel component. Among several solvents used, methanol was the best solvent, which showed the highest yield (98%) of benzoin in the presence of 5 mol% of either the rotaxane and the axle catalysts. The benzoin condensations of aromatic aldehydes catalyzed by the chiral rotaxanes were studied in detail and found to give optically active benzoins with 0-32% e.e. in 5-92% yield depending on the structure of the rotaxane and the reaction conditions employed. From the results, two intrarotaxane chirality transfers are confirmed: (i) through-space chirality transfer from wheel to axle and (ii) through-bond chirality transfer controlled with an achiral wheel. Because these asymmetric reaction fields are specific to the rotaxane structure, the importance and possibility of the rotaxane field as a particular reaction field are demonstrated. Copyright Taylor & Francis Group.
- Tachibana, Yuya,Kihara, Nobuhiro,Nakazono, Kazuko,Takata, Toshikazu
-
scheme or table
p. 1182 - 1205
(2010/09/04)
-
- Methylene-bridged bis(benzimidazolium) salt as a highly efficient catalyst for the benzoin reaction in aqueous media
-
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
-
experimental part
p. 912 - 915
(2008/10/09)
-
- A reductase-mimicking thiourea organocatalyst incorporating a covalently bound NADH analogue: Efficient 1,2-diketone reduction with in situ prosthetic group generation and recycling
-
A new class of bifunctional organocatalyst promotes the chemoselective reduction of diketone electrophiles at catalytic loadings in the presence of an inorganic co-reductant. The Royal Society of Chemistry.
- Procuranti, Barbara,Connon, Stephen J.
-
p. 1421 - 1423
(2008/02/03)
-
- Thiazolium salt immobilized on ionic liquid: An efficient catalyst and solvent for preparation of α-hydroxyketones
-
Aldehydes were efficiently converted to acyloins and benzoins using a new ionic liquid, 3-[2-(1-butyl-1H-imidazol-1,3-ium-3-yl)ethyl]-4,5-dimethyl-1,3- thiazol-3-ium dibromide 1. This ionic liquid is introduced as a catalyst and a solvent. Acyloins and benzoins were easily isolated from the reaction mixture via simple extraction, and the ionic liquid could be recycled for further use. Also, -hydroxy ketones with an aromatic and aliphatic substituent were prepared starting from aromatic and aliphatic aldehydes in the presence of ionic liquid 1.
- Mohanazadeh, Farajollah,Aghvami, Majid
-
p. 2467 - 2475
(2008/02/10)
-
- Bisphenols from furfurals by organocatalysis and gold catalysis
-
Four different benzoins were formed from furfurals by organocatalysis with heterocyclic carbenes, reduced to the diols and converted into propargyl ethers. The gold-catalyzed cyclization exclusively gave bisphenols of the bisdihydroisobenzofuran type. Georg Thieme Verlag Stuttgart.
- Hashmi, A. Stephen K.,W?lfle, Michael,Teles, J. Henrique,Frey, Wolfgang
-
p. 1747 - 1752
(2008/02/07)
-
- STABLE, AQUEOUS-PHASE, BASIC CATALYSTS AND REACTIONS CATALYZED THEREBY
-
A catalytic process for converting biomass-derived carbohydrates to liquid alkanes, alkenes, and/or ethers is described. The process uses combinations of self- and crossed-aldol condensation reactions, dehydration reactions, and hydrogenation reactions, over specified metal-containing catalysts, to yield alkane, alkene, and ether products from carbohydrate reactants.
- -
-
Page/Page column 15
(2008/06/13)
-
- Synthesis of 2,3-di(furan-2-yl)-5,6-dihydro-1,4-dioxine
-
Furoin transfers into enol-form under the alkali environment, responds with 1,2 saturated dihalide to obtain 2,3-di(furan-2-yl)-5,6-dihydro-1,4-dioxine. The structure of the compound was confirmed on the bases of elemental analysis and spectral studies. And tetrabutylammonium bromide has been found to promote the yields significantly.
- Yazhuo, Li,Feng, Zhang,Xuefeng, Jia,Dawei, Gao,Jikui, Sun,Yumin, Zhang,Tianqi, Zhao,Xiaodong, Chen
-
p. 361 - 364
(2007/10/03)
-