- 1,1,2,2-tetraphenyldisilane as a diversified radical reagent
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Reactivity of 1,1,2,2-tetraphenyldisilane as a radical reagent in ethanol was studied in reduction of alkyl bromides, addition to olefin and alkylation onto heteroaromatic bases with alkyl bromides. The present organodisilane showed moderate to good reactivities for these three types of radical reactions.
- Yamazaki, Osamu,Togo, Hideo,Matsubayashi, Sou,Yokoyama, Masataka
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- Nanosized ferric hydroxide catalyzed c-o cross-coupling of phenol and halides to generate phenoxy ether
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The iron-based catalyst can effectively catalyze the phenolic hydroxyl C-O bond formation reaction to give the corresponding phenoxy ethers. The reaction of phenol and methyl chloroacetate, for example, gives phenoxy acetic acid methyl ester in 98 % yield under the optimal reaction conditions. Among the iron-based catalysts, nanosized ferric hydroxide prepared through sol-gel method gives the best catalytic activity.
- Sun, Hongbin,Sun, Yuanhua,Tian, Xiaohua,Zhao, Yunxia,Qi, Xuan
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- Selective synthesis of p-ethylphenol by gas-phase alkylation of phenol with ethanol
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The selective synthesis of p-ethylphenol from gas-phase alkylation of phenol with ethanol was studied on zeolites HZSM5 and HMCM22 at 523 K. Phenol reacted directly with ethanol to form ethylphenylether by O-alkylation, and p- and o-ethylphenol isomers by C-alkylation; secondary products were m-ethylphenol and dialkylated compounds. Both zeolites presented similar activity and formed low amounts of ethylphenylether and dialkylated products, but exhibited different ethylphenol isomers distribution. In fact, for a contact time of 99.3gh/mol the selectivity to p-ethylphenol was 51.4% on HMCM22 and only 14.2% on HZSM5. The superior performance of zeolite HMCM22 for selectively producing p-ethylphenol was due to its narrower pore channels that suppressed the formation of dialkylated products and hampered by diffusional constraints the formation of o-ethylphenol. The maximum p-ethylphenol yield obtained on HMCM22 was 41% at a contact time of 250gh/mol; for higher contact times, p-ethylphenol was increasingly converted to m-ethylphenol. All the samples deactivated on stream because of coke formation. The carbon amount built on HMCM22 diminished when contact time was increased thereby indicating that coke was mainly formed from the reactants. Additional catalytic runs showed that phenol was the main responsible of catalyst deactivation, probably because of its strong adsorption on surface active sites.
- Sad,Duarte,Padró,Apesteguía
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- Electrogenerated base-promoted synthesis of organic carbonates from alcohols and carbon dioxide
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Electrogenerated bases promote the reaction between primary alcohols and carbon dioxide to give organic carbonates in excellent yields. Secondary alcohols are converted in moderate yields, whereas tertiary alcohols and phenols are unreactive. 1,2-Diols give a mixture of both cyclic and linear diand monocarbonates. These latter are intermediates in the reaction pathway leading to the cyclic derivatives.
- Casadei, Maria Antonietta,Cesa, Stefania,Rossi, Leucio
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- Synthesis of novel greener functionalized ionic liquids containing appended hydroxyl
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Novel "greener" functionalized ionic liquids have been prepared by the reaction of 1,2-epoxy propane and dilute sulfuric acid with [EMIm]Br or [BMIm]Br formed by alkyl bromide (RBr) and 1-methylimidazole. This kind of ionic liquid could be possibly used as green solvent and catalyst, especially as phase-transfer catalyst in organic chemistry (e.g., the synthesis of ethoxybenzene). Their chemical structures were characterized by 1H NMR, 13C NMR, and IR. Copyright Taylor & Francis Group, LLC.
- Feng, Guo Ren,Peng, Jia Jian,Qiu, Hua Yu,Jiang, Jian Xiong,Tao, Lan,Lai, Guo Qiao
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- Hexadecane Conversion on an Alumina–Nickel Catalyst
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Abstract: The conversion of hexadecane on a 4% Ni/Al2O3 catalyst in a temperature range of 20–300°C was studied using IR spectroscopy and catalytic methods. It was found that the dehydrogenation of hexadecane occurred at 20–100°C with the subsequent formation of aromatic products, but the rates of these processes were very low. As the reaction temperature was increased to 200°C, the 4% Ni/Al2O3 catalyst exhibited a maximum activity and high selectivity for the formation of 1-hexadecene, and aromatic compounds and cracking products were present in the reaction products. As the reaction temperature was further increased, the catalytic activity significantly decreased. This was due to the fact that polyaromatic deposits gradually accumulated on the catalyst surface in a temperature range of 200–300°C.
- Chesnokov,Chichkan,Paukshtis,Chesalov, Yu. A.,Krasnov
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- Simple and Rapid Determination of the Activation Parameters of Organic Reactions by Temperature-Dependent NMR Spectroscopy I. Application to Irreversible Reactions
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A rapid and convenient method for the evaluation of activation enthalpies and entropies of reactions in solutions was contrived. This was realized by the stepwise elevation of the temperature of a reaction system using a variable temperature apparatus of NMR spectrometer. A repetition of rapid collection of FIDs (Free Inductive Decays) at every plateau part of temperature at regular intervals allows us to determine the time-conversion curve, from which the rates at various temperatures were obtained as the first derivatives. Several examples of applications are shown.
- Satoh, Masahiro,Hirota, Minoru
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- Structure-Activity Relationship Studies to Identify Affinity Probes in Bis-aryl Sulfonamides That Prolong Immune Stimuli
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Agents that safely induce, enhance, or sustain multiple innate immune signaling pathways could be developed as potent vaccine adjuvants or coadjuvants. Using high-throughput screens with cell-based nuclear factor κB (NF-κB) and interferon stimulating response element (ISRE) reporter assays, we identified a bis-aryl sulfonamide bearing compound 1 that demonstrated sustained NF-κB and ISRE activation after a primary stimulus with lipopolysaccharide or interferon-α, respectively. Here, we present systematic structure-activity relationship (SAR) studies on the two phenyl rings and amide nitrogen of the sulfonamide group of compound 1 focused toward identification of affinity probes. The murine vaccination studies showed that compounds 1 and 33 when used as coadjuvants with monophosphoryl lipid A (MPLA) showed significant enhancement in antigen ovalbumin-specific immunoglobulin responses compared to MPLA alone. SAR studies pointed to the sites on the scaffold that can tolerate the introduction of aryl azide, biotin, and fluorescent rhodamine substituents to obtain several affinity and photoaffinity probes which will be utilized in concert for future target identification and mechanism of action studies.
- Chan, Michael,Lao, Fitzgerald S.,Chu, Paul J.,Shpigelman, Jonathan,Yao, Shiyin,Nan, Jason,Sato-Kaneko, Fumi,Li, Vicky,Hayashi, Tomoko,Corr, Maripat,Carson, Dennis A.,Cottam, Howard B.,Shukla, Nikunj M.
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- Ionic liquids as reagent and reaction medium: Preparation of alkyl aryl ethers
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Room temperature ionic liquid, [bmIm]OH, is used as a green recyclable reaction medium and reagent for the alkylation of phenols in excellent yields. The recovered ionic liquid was reused five to six times with consistent activity.
- Mohanazadeh, Farajollah,Aghvami, Majid
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- Selective hydrogenation of substituted styrene to alkylbenzene catalyzed by Al2O3 nanoparticles
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A straightforward and suitable protocol is described for the conversion of substituted styrene to alkylbenzenes in the presence of Al2O3 nanoparticles (nano-Al2O3) as heterogeneous solid catalysts using N2H4·H2O as a hydrogen source under mild reaction conditions. A complete conversion of styrene is obtained using nano-Al2O3 as a heterogeneous catalyst. Besides, this catalyst system is also successfully applied to promote the broad range of styrene substituted derivatives to their respective alkylbenzene compounds in moderate to higher conversions. The reaction is discovered to be heterogeneous in nature and nano-Al2O3 can be reused for three runs with no diminish in its performance. Besides, the analyses of the fresh and three times reused nano-Al2O3 solid by various analytical techniques. Transmission electron microscope indicates that the structural features, surface morphology, and particle size endure unchanged throughout the reaction. Some of the significant features of this procedure are mild reaction conditions, price effectiveness of the catalyst (Pd or Pt free catalyst), high conversion, functional group endurance, absence of noble metals/additives, and reusability of the catalyst. The scope of the reaction procedure can be extended to various linear and cyclic alkenes. Graphical abstract: [Figure not available: see fulltext.]
- Kaleeswari, Kalairajan,Tamil Selvi, Arunachalam
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- N-ARYL SULFONAMIDE DERIVATIVES AS VACCINE ADJUVANT
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Bis-aryl sulfonamide compounds and methods of using those compounds, e.g., in a method of enhancing or prolonging an immune response, are provided. For example, the compounds may be employed with a vaccine and optionally at least one other adjuvant and/or one or more TLR ligands, at least one MAP kinase inhibitor, or any combination thereof.
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Page/Page column 101-102
(2021/02/26)
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- Removal of Alkyl Sulfonates Using DABCO
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During the route development of a midstage clinical candidate, we were challenged with a presence of alkyl sulfonates, which were identified as potential genotoxic impurities in our active pharmaceutical ingredient (API). As a result, we initiated a development effort to identify a method to remove the alkyl sulfonates that would be amenable for scale-up. Herein, we report our effort toward the development of a general approach using DABCO (1,4-diazabicyclo[2.2.2]octane) to remove alkyl sulfonates that is both efficient and convenient from the bench to scale-up.
- Corazzata, Kaitlyn,Langston, Alexander,Lee, Elaine C.,Mo, Shunyan,Rose, Peter J.,Snodgrass, Joseph
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supporting information
(2021/11/30)
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- Mustard Carbonate Analogues as Sustainable Reagents for the Aminoalkylation of Phenols
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N,N-dialkyl ethylamine moiety can be found in numerous scaffolds of macromolecules, catalysts, and especially pharmaceuticals. Common synthetic procedures for its incorporation in a substrate relies on the use of a nitrogen mustard gas or on multistep syntheses featuring chlorine hazardous/toxic chemistry. Reported herein is a one-pot synthetic approach for the easy introduction of aminoalkyl chain into different phenolic substrates through dialkyl carbonate (β-aminocarbonate) chemistry. This new direct alcohol substitution avoids the use of chlorine chemistry, and it is efficient on numerous pharmacophore scaffolds with good to quantitative yield. The cytotoxicity via MTT of the β-aminocarbonate, key intermediate of this synthetic approach, was also evaluated and compared with its alcohol precursor.
- Annatelli, Mattia,Trapasso, Giacomo,Salaris, Claudio,Salata, Cristiano,Castellano, Sabrina,Aricò, Fabio
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supporting information
p. 3459 - 3464
(2021/05/24)
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- Light assisted O-alkylation of phenols to ethers using layered double oxides catalyst under green and mild conditions
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O-alkylation of phenols with dialkyl carbonates to ethers over layered double oxides (LDOs) catalyst under light irradiation is described. A base additive is not required when using the longer-chain diethyl carbonate as an alkylating agent owing to the sufficient basicity provided by LDOs. The synergism of substrate phenols molecules absorbing light to reach the first excited states with acid–base pairs of catalyst enhanced the interaction of reactant molecules with the surface of LDOs, simultaneously accelerating the cleavage of phenolic hydroxyl groups. A variety of phenols are tolerated in this system. This work reports a simple and environmentally benign catalytic process for the dehydrogenation of phenolic hydroxyl groups.
- Wang, Ruiyi,Wang, Xiaoyu,Zheng, Zhanfeng
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- Mechanistic basis for tuning iridium hydride photochemistry from H2evolution to hydride transfer hydrodechlorination
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The photochemistry of metal hydride complexes is dominated by H2 evolution, limiting access to reductive transformations based on photochemical hydride transfer. In this article, the innate H2 evolution photochemistry of the iridium hydride complexes [Cp?Ir(bpy-OMe)H]+ (1, bpy-OMe = 4,4'-dimethoxy-2,2′-bipyridine) and [Cp?Ir(bpy)H]+ (2, bpy = 2,2'-bipyridine) is diverted towards photochemical hydrodechlorination. Net hydride transfer from 1 and 2 to dichloromethane produces chloromethane with high selectivity and exceptional photochemical quantum yield (Φ ≤ 1.3). Thermodynamic and kinetic mechanistic studies are consistent with a non-radical-chain reaction sequence initiated by "self-quenching"electron transfer between excited state and ground state hydride complexes, followed by proton-coupled electron transfer (PCET) hydrodechlorination that outcompetes H-H coupling. This unique photochemical mechanism provides a new hope for the development of light-driven hydride transfer reactions.
- Barrett, Seth M.,Chambers, Matthew B.,Dempsey, Jillian L.,Kurtz, Daniel A.,Miller, Alexander J. M.,Pitman, Catherine L.,Stratakes, Bethany M.
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p. 6442 - 6449
(2020/07/15)
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- Transition-Metal-Free C-C, C-O, and C-N Cross-Couplings Enabled by Light
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Transition-metal-catalyzed cross-couplings to construct C-C, C-O, and C-N bonds have revolutionized chemical science. Despite great achievements, these metal catalysts also raise certain issues including their high cost, requirement of specialized ligands, sensitivity to air and moisture, and so-called "transition-metal-residue issue". Complementary strategy, which does not rely on the well-established oxidative addition, transmetalation, and reductive elimination mechanistic paradigm, would potentially eliminate all of these metal-related issues. Herein, we show that aryl triflates can be coupled with potassium aryl trifluoroborates, aliphatic alcohols, and nitriles without the assistance of metal catalysts empowered by photoenergy. Control experiments reveal that among all common aryl electrophiles only aryl triflates are competent in these couplings whereas aryl iodides and bromides cannot serve as the coupling partners. DFT calculation reveals that once converted to the aryl radical cation, aryl triflate would be more favorable to ipso substitution. Fluorescence spectroscopy and cyclic voltammetry investigations suggest that the interaction between excited acetone and aryl triflate is essential to these couplings. The results in this report are anticipated to provide new opportunities to perform cross-couplings.
- Liu, Wenbo,Li, Jianbin,Querard, Pierre,Li, Chao-Jun
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p. 6755 - 6764
(2019/05/06)
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- Piperazine adenosine monophosphate activated protein kinase (AMPK) agonist and medical application thereof
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The invention discloses a piperazine compound with AMPK agonist activity, and a preparation method and medical application of the piperazine compound. The piperazine compound is a compound shown as aformula (I) (please see the specifications for the formula), and a pharmaceutically acceptable salt or ester or a prodrug or N-oxide or solvate thereof. The compound can be used for preparing drugs for preventing or treating AMPK-mediated diseases.
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Paragraph 0459; 0461-0462
(2019/11/12)
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- Highly selective conversion of guaiacol to: Tert -butylphenols in supercritical ethanol over a H2WO4 catalyst
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The conversion of guaiacol is examined at 300 °C in supercritical ethanol over a H2WO4 catalyst. Guaiacol is consumed completely, meanwhile, 16.7% aromatic ethers and 80.0% alkylphenols are obtained. Interestingly, tert-butylphenols are produced mainly with a high selectivity of 71.8%, and the overall selectivity of 2,6-di-tert-butylphenol and 2,6-di-tert-butyl-4-ethylphenol is as high as 63.7%. The experimental results indicate that catechol and 2-ethoxyphenol are the intermediates. Meanwhile, the WO3 sites play an important role in the conversion of guaiacol and the Br?nsted acid sites on H2WO4 enhance the conversion and favour a high selectivity of the tert-butylphenols. The recycling tests show that the carbon deposition on the catalyst surface, the dehydration and partial reduction of the catalyst itself are responsible for the decay of the H2WO4 catalyst. Finally, the possible reaction pathways proposed involve the transetherification process and the alkylation process during guaiacol conversion.
- Mai, Fuhang,Cui, Kai,Wen, Zhe,Wu, Kai,Yan, Fei,Chen, Mengmeng,Chen, Hong,Li, Yongdan
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p. 2764 - 2771
(2019/02/01)
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- A new alkylation of aryl alcohols by boron trifluoride etherate
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The ethylation of aryl alcohols by an ethyl moiety of boron trifluoride etherate is described. The reaction proceeded cleanly and afforded good yields of the corresponding aryl ethyl ethers. It tolerated the presence of functional groups such as aryl, alkyl, halogens, nitro, nitrile, and amino. However, the presence of amino or nitro groups ortho to a hydroxyl group of an aryl compound drastically reduced the yields of the anticipated products due to the chelation of the aforementioned functional groups with boron trifluoride etherate. A nitrogen atom in the aromatic ring system, as exemplified by hydroxypyridine and 8-hydroxyquinoline, completely inhibited the reaction. Resorcinol, hydroquinone, and aryl alcohols with aldehyde functions decomposed under the reaction conditions.
- Jumbam, Ndze Denis,Maganga, Yamkela,Masamba, Wayiza,Mbunye, Nomthandazo I.,Mgoqi, Esethu,Mtwa, Sphumusa
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- Decarbonylation through Aldehydic C-H Bond Cleavage by a Cationic Iridium Catalyst
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We report the decarbonylation of aldehydes through an aldehydic C-H bond cleavage catalyzed by a cationic iridium/bisphosphine catalyst. The reaction proceeds under relatively mild conditions to give the corresponding hydrocarbon products in moderate to high yields. In addition, this cationic iridium catalyst system can be applied to an asymmetric hydroacylation of ketones.
- Shirai, Tomohiko,Sugimoto, Kazuki,Iwasaki, Masaya,Sumida, Ryuki,Fujita, Harunori,Yamamoto, Yasunori
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p. 972 - 976
(2019/05/10)
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- Chemoselective deoxygenation of ether-substituted alcohols and carbonyl compounds by B(C6F5)3-catalyzed reduction with (HMe2SiCH2)2
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B(C6F5)3-catalyzed deoxygenation of ether-substituted alcohols and carbonyl compounds has been developed using (HMe2SiCH2)2 as the reductant. This unique reagent shows distinct superiority over traditional one silicon-centered hydrosilanes, giving the corresponding alkanes in high yields with good tolerance of ethers, aryl halides and alkenes. The control experiments suggest that (HMe2SiCH2)2 might facilitate the approach in an intramolecular Si/O activation manner.
- Yang, Wenyu,Gao, Lu,Lu, Ji,Song, Zhenlei
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supporting information
p. 4834 - 4837
(2018/05/23)
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- Copper(I)-USY as a Ligand-Free and Recyclable Catalyst for Ullmann-Type O-, N-, S-, and C-Arylation Reactions: Scope and Application to Total Synthesis
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The copper(I)-doped zeolite CuI-USY proved to be a versatile, efficient, and recyclable catalyst for various Ullmann-type coupling reactions. Easy to prepare and cheap, this catalytic material enables the arylation and heteroarylation of diverse O-, N-, S-, and C-nucleophiles under ligand-free conditions while exhibiting large functional group compatibility. The facility of this catalyst to promote C-O bond formation was further demonstrated with the total synthesis of 3-methylobovatol, a naturally occurring diaryl ether of biological relevance. From a mechanistic viewpoint, two competitive pathways depending on the nature of the nucleophile and consistent with the obtained results have been proposed.
- Garnier, Tony,Danel, Mathieu,Magné, Valentin,Pujol, Anthony,Bénéteau, Valérie,Pale, Patrick,Chassaing, Stefan
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p. 6408 - 6422
(2018/05/31)
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- Synthesis of NHC Pincer Hydrido Nickel Complexes and Their Catalytic Applications in Hydrodehalogenation
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The C(carbene)N(amino)N(amine)-pincer nickel(II) bromides 1a-c were hydrogenated to the corresponding nickel(II) hydrides 2a-c by (EtO)3SiH/NaOtBu or NaBH4. These nickel(II) hydrides 2a-c were characterized by NMR and IR spectroscopy as well as X-ray diffraction. The catalytic performance of complex 2b for hydrodehalogenation reactions was explored. With a combination of 3 mol % catalyst loading, (EtO)3SiH/NaOtBu/toluene/80 °C and different reaction times, organic halides were successfully reduced to the related alkanes. A catalytic radical mechanism is proposed and partially verified by experiments.
- Wang, Zijing,Li, Xiaoyan,Sun, Hongjian,Fuhr, Olaf,Fenske, Dieter
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p. 539 - 544
(2018/03/08)
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- Dimethyl sulfoxide-accelerated reductive deamination of aromatic amines with t-BuONO in tetrahydrofuran
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An efficient method for the conversion of aryl amines into arenes by a one-pot reductive deamination has been achieved. It was found the reductive deamination using t-BuONO in tetrahydrofuran could be accelerated by dimethyl sulfoxide and provided the deamination products with good yields under mild conditions. A plausible mechanism is discussed.
- Fang, Lu,Qi, Liang,Ye, Longfei,Pan, Zhentao,Luo, Wenjun,Ling, Fei,Zhong, Weihui
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p. 579 - 583
(2018/11/27)
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- Novel sulfonamide compound, preparation method, and use of novel sulfonamide compound as protein tyrosine phosphatase 1B inhibitor
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The invention relates to a novel sulfonamide compound in a structure of a general formula I as shown in the specification, or pharmaceutically acceptable salt and a preparation method of the novel sulfonamide compound, and further relates to a drug composition containing the compound as shown as the general formula I or the pharmaceutically acceptable salt of the compound, and a use of the compound or the pharmaceutically acceptable salt for preparing a drug for preventing and/or treating symptoms or diseases such as hyperglycemia and diabetes mellitus type 2 since the compound as shown as the general formula I or the pharmaceutically acceptable salt of the compound has activity of inhibiting a protein tyrosine phosphatase 1B (PTP 1B).
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Paragraph 0019
(2017/12/29)
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- Benzene C-H Etherification via Photocatalytic Hydrogen-Evolution Cross-Coupling Reaction
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Aryl ethers can be constructed from the direct coupling between the benzene C-H bond and the alcohol O-H bond with the evolution of hydrogen via the synergistic merger of photocatalysis and cobalt catalysis. Utilizing the dual catalyst system consisting of 3-cyano-1-methylquinolinum photocatalyst and cobaloxime, intermolecular etherification of arenes with various alcohols and intramolecular alkoxylation of 3-phenylpropanols with formation of chromanes are accomplished. These reactions proceed at remarkably mild conditions, and the sole byproduct is equivalent hydrogen gas.
- Zheng, Yi-Wen,Ye, Pan,Chen, Bin,Meng, Qing-Yuan,Feng, Ke,Wang, Wenguang,Wu, Li-Zhu,Tung, Chen-Ho
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supporting information
p. 2206 - 2209
(2017/05/12)
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- B(C6F5)3-Catalyzed Chemoselective Defunctionalization of Ether-Containing Primary Alkyl Tosylates with Hydrosilanes
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Catalytic C(sp3)?O bond cleavage promoted by B(C6F5)3 /Et3SiH proceeds preferentially with primary tosylates in the presence of primary and secondary silyl ethers and aryl ethers. This reactivity difference enables the chemoselective defunctionalization of several 1,n-diols, and the efficiency of the new procedure is highlighted by the selective deoxygenation of the hydroxymethyl group of an orthogonally protected carbohydrate. Tosylates with an adjacent phenyl group are cleaved with anchimeric assistance.
- Chatterjee, Indranil,Porwal, Digvijay,Oestreich, Martin
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supporting information
p. 3389 - 3391
(2017/03/17)
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- Intermolecular C–O Coupling Using Hemicucurbituril Supported Ionic Liquid Phase Catalyst
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Abstract: Hemicucurbituril supported ionic liquid phase catalyst (HmCucSILP) has been synthesized by anchoring multilayer of ionic liquid ([Bmim]Cl) containing Pd(OAc)2 and X-phos on the surface of hemicucurbit[6]uril. The HmCucSILP was effectively employed in intermolecular C–O coupling of aryl halides with sodium alkoxides for the synthesis of alkyl aryl ethers. Graphical Abstract: [Figure not available: see fulltext.]
- Kurane, Rajanikant,Bansode, Prakash,Khanapure, Sharanabasappa,Kale, Dolly,Salunkhe, Rajashri,Rashinkar, Gajanan
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p. 2485 - 2494
(2016/11/25)
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- Masked N-Heterocyclic Carbene-Catalyzed Alkylation of Phenols with Organic Carbonates
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An easily prepared masked N-heterocyclic carbene, 1,3-dimethylimidazolium-2-carboxylate (DMI-CO2), was investigated as a “green” and inexpensive organocatalyst for the alkylation of phenols. The process made use of various low-toxicity and renewable alkylating agents, such as dimethyl- and diethyl carbonate, in a focused microwave reactor. DMI-CO2 was found to be a very active catalyst and excellent yields of a range of aryl alkyl ethers were obtained under relatively benign conditions. The observed difference in the conversion behavior of phenol methylation, in the presence of either the carbene or 1,8-diazabicycloundec-7-ene (DBU) catalyst, was rationalized on the basis of mechanistic investigations. The primary mode of action for the N-heterocyclic carbene is nucleophilic catalysis. Activation of the dialkyl carbonate electrophile results in concomitant evolution of an organo-soluble alkoxide, which deprotonates the phenolic starting material. In contrast, DBU is initially protonated by the phenol and thus consumed. Subsequent regeneration and participation in nucleophilic catalysis only becomes significant after some phenolate alkylation occurs.
- Lui, Matthew Y.,Yuen, Alexander K. L.,Masters, Anthony F.,Maschmeyer, Thomas
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p. 2312 - 2316
(2016/10/24)
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- Orthogonal Discrimination among Functional Groups in Ullmann-Type C-O and C-N Couplings
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The copper-catalyzed arylation of nucleophiles has been established as an efficient methodology for the formation of C-C and C-heteroatom bonds. Considering the advances during the last two decades, the ligand choice plays a key role in such transformations and can strongly influence the catalytic efficiency. The applicability of these Ullmann-type coupling reactions regarding the orthogonal selectivity of different functional groups constitutes a challenging subject for current synthetic strategies. Herein, we report a useful toolkit of Cu-based catalysts for the chemoselective arylation of a wide-range of nucleophiles in competitive reactions using aryl iodides and bromides. We show in this work that the arylation of all kinds of amides can be orthogonal to that of amines (aliphatic or aromatic) and phenol derivatives. This high chemoselectivity can be governed by the use of different ligands, yielding the desired coupling products under mild conditions. The selectivity trends are maintained for electronically biased iodobenzene and bromobenzene electrophiles. Radical clock experiments discard the occurrence of radical-based mechanisms.
- Rovira, Mireia,Soler, Marta,Güell, Imma,Wang, Ming-Zheng,Gómez, Laura,Ribas, Xavi
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supporting information
p. 7315 - 7325
(2016/09/09)
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- Novel, potent, selective and cellular active ABC type PTP1B inhibitors containing (methanesulfonyl-phenyl-amino)-acetic acid methyl ester phosphotyrosine mimetic
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Protein tyrosine phosphatase 1B (PTP1B) which plays an important role in the negative regulation of insulin and leptin pathway has emerged as a novel promising therapeutic target for the treatment of type 2 diabetes mellitus and obesity. Upon careful study, a series of novel scaffold and simple synthesis method inhibitors were discovered based on the analysis of X-ray crystal structures of PTP1B/inhibitor complexes and docking simulations. Among them, compound P7 exhibited high inhibitory activity (IC50 = 222 nM) with moderate selectivity (8-fold) over T-cell PTPase (TCPTP) through interacting with the A, B and C binding sites of PTP1B enzyme. Further studies on cellular activities revealed that compound P7 could enhance insulin-mediated IRβ phosphorylation and insulin-stimulated glucose uptake.
- Liu, Peihong,Du, Yongli,Song, Lianhua,Shen, Jingkang,Li, Qunyi
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p. 7079 - 7088
(2015/11/11)
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- Air-stable palladium(0) phosphine sulfide catalysts for Ullmann-type C-N and C-O coupling reactions
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This paper describes an efficient procedure for palladium(0)-catalyzed N-arylation and O-arylation of aryl halides by Ullmann-type cross coupling reaction under mild reaction conditions in a short reaction time. Two phosphine sulphide ligands and their corresponding Pd(0) complexes namely [Pd(p2S2)(dba)] and [Pd(pp3S4)(dba)], were synthesized, where p2S2 is 1,2-bis(diphenylphosphino)ethane disulfide, pp3S4 is tris[2-(diphenylphosphino)ethyl]phosphine tetrasulfide and dba is dibenzylideneacetone. Optimal reaction conditions were determined for the arylation reactions using iodobenzene and benzimidazole by varying temperature, solvent, base and catalyst loading. The cross coupling reactions were carried out taking iodobenzenes/bromobenzenes and a wide variety of substituted aryl amines/phenols/alcohols with different steric and electronic properties to afford the desired N-aryl amines/diaryl ethers/alkyl aryl ethers in good to excellent yield (70-94%).
- Majumder, Arpi,Gupta, Ragini,Mandal, Mrinmay,Babu, Madhu,Chakraborty, Debashis
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- The ortho-substituent effect on the Ag-Catalysed decarboxylation of benzoic acids
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A combined experimental and computational investigation on the Ag-catalysed decarboxylation of benzoic acids is reported herein. The present study demonstrates that a substituent at the ortho position exerts dual effects in the decarboxylation event. On one hand, ortho-substituted benzoic acids are inherently destabilised starting materials compared to their meta- And para-substituted counterparts. On the other hand, the presence of an ortho-electron-withdrawing group results in an additional stabilisation of the transition state. The combination of both effects results in an overall reduction of the activation energy barrier associated with the decarboxylation event. Furthermore, the Fujita- Nishioka linear free energy relationship model indicates that steric bulk of the substituent can also exert a negative effect by destabilising the transition state of decarboxylation.
- Grainger, Rachel,Cornella, Josep,Blakemore, David C.,Larrosa, Igor,Campanera, Josep M.
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supporting information
p. 16680 - 16687
(2015/03/05)
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- Ligand-free Ullmann-type C-heteroatom couplings under practical conditions
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A new practical ligand-free protocol for copper-catalyzed C-heteroatom cross-coupling reactions (Ullmann-type) is described. The use of dimethyl sulfoxide (DMSO) as the solvent overcomes the need to use organic auxiliary ligands; thus, DMSO is revealed as a nontoxic and superior solvent for Ullmann-type coupling reactions. This method allows the arylation of a wide range of amides, alcohols, and amines under practical conditions with bromobenzene and iodobenzene derivatives and will likely find direct application in current organic synthesis. The competitive reactivity among different functional groups is reported and rationalized, and the possibility to achieve selective arylation reactions is demonstrated. Copyright
- Gueell, Imma,Ribas, Xavi
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supporting information
p. 3188 - 3195
(2014/06/09)
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- SNAAP sulfonimidate alkylating agent for acids, alcohols, and phenols 1
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Stable, crystalline ethyl N-tert-butyl-4-nitrobenzenesulfonimidate has been prepared in high yield by direct O-ethylation of N-tert-butyl-4- nitrobenzenesulfonamide with iodoethane and silver(I) oxide in dichloromethane. This sulfonimidate directly ethylates various acids to esters; the stronger the acid, the faster it alkylates and in higher yield. It readily ethylates alcohols and phenols to ethers at room temperature in the presence of tetrafluoroboric acid catalyst without molecular rearrangements or racemization. We have defined these reactions as SNAAP alkylations: [substitution, nucleophilic of acids, alcohols and phenols]. The hard sulfonimidate alkylating agent is chemoselective, preferring oxygen > nitrogen > sulfur. The sulfonamide byproduct of alkylation is readily recycled to the sulfonimidate. Georg Thieme Verlag Stuttgart . New York.
- Maricich, Tom J.,Allan, Matthew J.,Kislin, Brett S.,Chen, Andrea I-T.,Meng, Fan-Chun,Bradford, Christine,Kuan, Nai-Chia,Wood, Jeremy,Aisagbonhi, Omonigho,Poste, Alethea,Wride, Dustin,Kim, Sylvia,Santos, Therese,Fimbres, Michael,Choi, Dianne,Elia, Haydi,Kaladjian, Joseph,Abou-Zahr, Ali,Mejia, Arturo
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p. 3361 - 3368
(2014/01/06)
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- Synthesis, reactivity, and catalytic application of a nickel pincer hydride complex
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The nickel(II) hydride complex [(MeN2N)Ni-H] (2) was synthesized by the reaction of [(MeN2N)Ni-OMe] (6) with Ph2SiH2 and was characterized by NMR and IR spectroscopy as well as X-ray crystallography. 2 was unstable in solution, and it decomposed via two reaction pathways. The first pathway was intramolecular N-H reductive elimination to give MeN2NH and nickel particles. The second pathway was intermolecular, with H2, nickel particles, and a five-coordinate Ni(II) complex [(MeN2N)2Ni] (8) as the products. 2 reacted with acetone and ethylene, forming [( MeN2N)Ni-OiPr] (9) and [(MeN 2N)Ni-Et] (10), respectively. 2 also reacted with alkyl halides, yielding nickel halide complexes and alkanes. The reduction of alkyl halides was rendered catalytically, using [(MeN2N)Ni-Cl] (1) as catalyst, NaOiPr or NaOMe as base, and Ph2SiH2 or Me(EtO)2SiH as the hydride source. The catalysis appears to operate via a radical mechanism.
- Breitenfeld, Jan,Scopelliti, Rosario,Hu, Xile
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experimental part
p. 2128 - 2136
(2012/06/01)
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- CYCLOALKYL METHOXYBENZYL PHENYL PYRAN DERIVATIVES AS SODIUM DEPENDENT GLUCOSE CO TRANSPORTER (SGLT2) INHIBITORS
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The invention relates to the cycloalkyl methoxybenzyl phenyl pyran derivatives as Sodium dependent glucose co transporter (SGLT) inhibitors, particularly SGLT2 and method of treating diseases, conditions and/or disorders inhibited by SGLT2 with them, and processes for preparing them.
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Page/Page column 19-20
(2012/03/26)
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- Fluoroform-derived CuCF3 for low-cost, simple, efficient, and safe trifluoromethylation of aryl boronic acids in air
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Easy does it: Aryl boronic acids undergo smooth and selective trifluoromethylation with low-cost fluoroform-derived CuCF3 in DMF in non-dried air. The reaction occurs under mild conditions (1 atm, room temperature), exhibits unprecedented funct
- Novak, Petr,Lishchynskyi, Anton,Grushin, Vladimir V.
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supporting information; experimental part
p. 7767 - 7770
(2012/08/29)
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- Sulfur and nitrogen mustard carbonate analogues
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Sulfur and nitrogen half-mustard compounds lose their aggressive properties when the chlorine atom is replaced by a carbonate moiety. The anchimeric effect of the novel mustard carbonate analogues is investigated. The reaction follows first-order kinetics, does not need any base, and occurs with -OH, -NH and acidic -CH nucleophiles. Most of these molecules are unexplored and might provide a novel strategy for the preparation of compounds previously not easily accessible. Copyright
- Arico, Fabio,Chiurato, Matteo,Peltier, Josephine,Tundo, Pietro
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scheme or table
p. 3223 - 3228
(2012/07/31)
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- Selective one-pot synthesis of symmetrical and unsymmetrical di- and triarylamines with a ligandless copper catalytic system
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The one-pot synthesis of symmetrical or unsymmetrical di- or triarylamines using aryl iodides or bromides and LiNH2 as ammonia source is reported. This highly selective method is based, for the first time, on a copper-catalyzed system, which does not require the presence of any additional ligand.
- Tlili, Anis,Monnier, Florian,Taillefer, Marc
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body text
p. 6408 - 6410
(2012/07/27)
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- Palladium-catalyzed hydrodechlorination of ary chlorides and its mechanism
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Successful hydrodechlorinations of aryl chlorides were carried out in the presence of palladium catalyst supported by dppf (1,1′- bis(diphenylphosphino)ferrocene) and sodium formate in DMA (N,N- dimethylacetamide). A series of substituted aryl chlorides as substrates were studied to investigate the influence of electronic effects on the reaction. It was found that the substrates with electron-donating groups are more active than those with electron-withdrawing groups. A proposed mechanism of hydrodechlorination via decarboxylation and reductive elimination was discussed with the supported of in situ IR data. It is suggested that the decarboxylation is the key step of the reaction. This inference of the mechanism is consistent with the results from the in situ IR experiments.
- Zhang, Chen,Li, Xiaoyan,Sun, Hongjian
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experimental part
p. 133 - 136
(2011/04/15)
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- Three component reaction of arynes with cyclic ethers and active methines: Synthesis of ω-trichloroalkyl phenyl ethers
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Synthesis of ω-chlorinated alkyl phenyl ethers by tandem reaction of arynes with cyclic ethers and active methines was achieved. Reaction of benzenediazonium 2-carboxylate with tetrahydropyran or tetrahydrofuran in refluxing chloroform afforded 6,6,6-trichlorohexyl phenyl ether or 5,5,5-trichloropentyl phenyl ether in 40% and 61% yields, respectively. When dichloroacetonitrile was used as a reactant, 5,5-dichloro-5-cyanopentyl phenyl ether was obtained in 61% yield. While benzenediazonium carboxylate did not react with epoxides, reaction of benzyne derived from 2-(trimethylsilyl)phenyl triflate with epoxides afforded 3,3,3-trichloropropyl phenyl ethers in good yields as isomeric mixtures. The reaction of oxetanes with benzyne was also reported.
- Okuma, Kentaro,Fukuzaki, Yuta,Nojima, Akiko,Sou, Ayumi,Hino, Haruna,Matsunaga, Nahoko,Nagahora, Noriyoshi,Shioji, Kosei,Yokomori, Yoshinobu
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experimental part
p. 1238 - 1247
(2010/12/20)
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- ETHOXYPHENYLMETHYL INHIBITORS OF SGLT2
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The present invention relates to new ethoxyphenylmethyl modulators of SGLT2, pharmaceutical compositions thereof, and methods of use thereof. (Formula I)
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Page/Page column 30
(2010/05/13)
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- Selective one-pot access to symmetrical or unsymmetrical diaryl ethers by copper-catalyzed double arylation of a simple oxygen source
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Great CO-mbination: A novel method is reported for the controlled one-pot synthesis of various symmetrical or unsymmetrical diaryl ethers by double arylation of a simple inorganic oxygen source (see scheme). This versatile and highly selective process is based on the use of a cheap and low toxicity copper catalytic system.
- Tlili, Anis,Monnier, Florian,Taillefer, Marc
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supporting information; experimental part
p. 12299 - 12302
(2011/02/16)
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- Etherification of darylmethanols and 1-phenylalkan-1-ols over platinum on carbon
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In the presence of platinum on carbon (Pt/C), diarylmethanols and donor substituted 1-phenylalkan-1-ols undergo cross-etherification with primary and secondary alcohols.
- Thiemann, Thies
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experimental part
p. 515 - 525
(2010/04/23)
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- A comparative study on the binding behaviors of β-cyclodextrin and its two derivatives to four fanlike organic guests
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(Figure Presented) Four fanlike organic compounds, 1-ethoxybenzene (EOB), 1-butoxybenzene (BOB), 1-dodecyloxybenzene (DOB), and 1-(dodecyloxy)-2- methoxybenzene (DOMB), were chosen as guests, and β-cyclodextrin (β-CD) and its two derivatives, mono(2-O-2-methyl)-β-CD and mono(2-O-2-hydroxy-propyl)-β-CD, were chosen as hosts. Energy changes involved in host-guest inclusion processes were clearly obtained by applying semiempirical PM3 calculations. According to this, probable structures of the host-guest inclusion complexes were proposed. The inclusion systems in aqueous solution were investigated by UV-vis spectroscopy and nuclear magnetic resonance (1H NMR) titration, and the formation constants (K) of the inclusion complexes were determined using the Benesi-Hildebrand equation. Moreover, two solid inclusion complexes of β-CD with EOB and DOB were prepared and characterized by Fourier transform infrared spectra, X-ray powder diffraction, 1H NMR, electrospray ionization mass spectrometry, and thermogravimetric analyses. Results showed that the host-guest stoichiometrics in the inclusion complexes were all 1:1 both in solid state and in aqueous solution. As for the same host, the values of K increased in the order EOB BOB DOB, in strong association with the fan handle in the fanlike molecules; that is to say, the K values increased with increasing carbon chain length of substituent on benzene ring. In addition, the K values of DOMB complexes were larger than those of DOB complexes for the same CD, indicating that the introduction of an extra o-methoxyl group on DOB further stabilized the CD inclusion complexes. The decomposition activation energies of EOB-β-CD and DOB-β-CD were very similar but significantly larger than that of free β-CD.
- Le, Xin Song,Hai, Ming Wang,Xue, Qing Guo,Bai, Lei
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supporting information; experimental part
p. 8305 - 8316
(2009/04/11)
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- Transformation of tertiary amines into alkylating reagents by treatment with 2-chloro-4,6-dimethoxy-1,3,5-triazine. A synthetic application of side-reaction accompanying coupling by means of 4-(4,6-dimethoxy-[1,3,5] triazin-2-yl)-4-methyl-morpholin-4-ium chloride (DMTMM)
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Mild reaction conditions are described for the preparation of a number of alkyl chlorides and 2-dialkyl(aryl)amino-4,6-dirnethoxy-1,3,5-triazines by dealkylation of quaternary triazinylammonium chlorides formed as reactive intermediates in reaction of tertiary amines with 2-chloro-4,6-dimethoxy-1,3,5- triazine. The high selectivity of substitution was observed within the reactivity order of the alkyl groups: benzyl ～ allyl > methyl > n-alkyl. Studies on dealkylation of S-(-)-J-dimethyl-(1-phenylethyl)amine to R-(+)-1-chloro-1-phenylethane revealed that reaction proceeded with an inversion of configuration on the carbon atom as may be expected for SN2 type substitution. The scope of reaction was extended by exchange of anion in quaternary triazinylammonium chlorides with 1-, SCN-, C6H5O-, CH3COO- followed by N-dealkylation step.
- Kolesinska,Kaminski
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experimental part
p. 2115 - 2123
(2009/04/07)
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- Solvent-free Williamson synthesis: An efficient, simple, and convenient method for chemoselective etherification of phenols and bisphenols
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Etherification of phenols with dimethyl- and diethylsulfates and benzyl chloride was performed efficiently in the presence of a suitable solid base, NaHCO3 or K2CO3, under solvent-free conditions. The reaction proceeded rapidly at low temperature, and the corresponding ethers were obtained with high purity and excellent yield. Selective etherification of electron-poor phenols in the presence of electron-rich ones and also selective mono-etherification of bisphenols are the noteworthy advantages of this method. This method is environmentally friendly. Copyright Taylor & Francis Group, LLC.
- Massah, Ahmad R.,Mosharafian, Masumeh,Momeni, Ahamad R.,Aliyan, Hamid,Naghash, H. Javaherian,Adibnejad, Mohamad
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p. 1807 - 1815
(2008/02/02)
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- Process for making diaryl carbonate
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Diphenyl carbonate is produced by reacting phenol with diethyl carbonate in a series of fixed bed reactors each of which is connected at different position on a distillation column via side draw and return streams. The composition of material in a distillation column varies along the length of the column, which is predictable under a given set of conditions of temperature and pressure, thus withdrawing streams at different stages in the column, allows the reactor receiving the feed from a particular stage to be operated under conditions to maximize the desired reaction, while allowing the unreacted or byproduct to go back into the distillation and be sent to a stage (by the equilibrium of the distillation) where they are favorably treated in a reactor.
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Page/Page column 4-7
(2008/06/13)
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- Process for producing organic carbonates
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A process for producing various organic carbonates by performing transesterification and disproportionation reactions in dual vapor/liquid phase mode preferably in the presence of solid catalyst composition selected from the group consisting of oxides, hydroxides, oxyhydroxides or alkoxides of two to four elements from Group IV, V and VI of the Periodic Table supported on porous material which has surface hydroxyl groups and the method of reactivating catalyst deactivated by polymer deposition by contacting the deactivated catalyst with a solution of hydroxy containing compound in a solvent such as benzene or THF.
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Page/Page column 8
(2008/06/13)
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- ALKYLATION OF HYDROXYARENES WITH OLEFINS, ALCOHOLS AND ETHERS IN IONIC LIQUIDS
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Hydroxyarenes are alkylated using an ionic liquid catalyst system with olefins, alcohols, or ethers as alkylating agents. The ionic liquid catalyst system comprises chloroindate (III) anions. The reactions may be conducted at moderate temperatures and pressures to yield commercially relevant alkylated hydroxyarene compounds.
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Page/Page column 22
(2008/06/13)
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- Efficient methods for the preparation of alkyl-aryl and symmetrical or unsymmetrical dialkyl ethers between alcohols and phenols or two alcohols by oxidation-reduction condensation
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Oxidation-reduction condensation via alkoxydiphenylphosphines (diphenylphosphinite esters) (1), generated in situ from chlorodiphenylphosphine (2) and alcohols, 2,6-dimethyl-1,4-benzoquinone (3), and phenols proceeds smoothly to afford alkyl-aryl ethers in good to high yields under neutral conditions. In a similar fashion, a new and efficient method for the preparation of symmetrical or unsymmetrical dialkyl ethers in good to high yields is established via tetrafluoro-1,4-benzoquinone (fluoranil) (4), alcohols, and 1 formed in situ from nBuLi-treated alcohols and 2. This method is applicable also to the etherification of chiral secondary or tertiary alcohols with retention or inversion of configurations. The inverted ethers are afforded by treating chiral alkoxydiphenylphosphines and achiral alcohols, while the reaction of achiral alkoxydiphenylphosphines and chiral alcohols forms retained ethers.
- Shintou, Taichi,Mukaiyama, Teruaki
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p. 7359 - 7367
(2007/10/03)
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- N- and O-arylation with triphenylantimony ortho-phenylenedioxides
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2,2,2-Triphenyl-1,3,2-benzodioxastibolanes react with alcohols, phenols, and amines in the presence of copper salts to give the corresponding O- and N-phenyl derivatives. Cyclic SbV dialkoxide containing an electron-withdrawing nitro group in t
- Stolyarova,Shavyrin,Finet,Fedorov
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p. 1736 - 1739
(2007/10/03)
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