- 4,4'-TETRAMETHYLDIAMINODIPHENYLMETHANOL FROM TETRABASE WITH HEMIN IN ACETIC ACID
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4,4'-Tetramethyldiaminodiphenylmethanol was formed in 90 percent yield by oxidizing Tetrabase with hemin and hydrogen peroxide at 4 deg C in acetic acid (80 percent).
- Ohkoshi, Atsushi,Takahashi, Katsunobu,Matsushima, Ayako,Abe, Kazuya,Inada, Yuji
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- New ferrocenyl-containing organic hole-transporting materials for perovskite solar cells in regular (n-i-p) and inverted (p-i-n) architectures
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Three triphenylamine derivatives containing ferrocenyl groups (JW6, JW7 and JW8) were synthesized by facile syntheses. Their HOMO levels match the valence band energy of CH3NH3PbI3. The introduction of ferrocenyl was aimed to obtain hole transporting materials with high mobility for perovskite solar cells. JW7 shows higher hole mobility (4.2 × 10?4 cm2 V?1 s?1) than JW6 (1.3 × 10?4 cm2 V?1 s?1) and JW8 (1.5 × 10?4 cm2 V?1 s?1). Their film-forming properties are affected by their molecule structures. The methoxyl and N,N-dimethyl terminal substituents of JW7 and JW8 are beneficial for having better solubility than JW6. The regular mesoporous TiO2-based perovskite solar cells (n-i-p) and the inverted planar heterojunction perovskite solar cells (p-i-n) fabricated using JW7 show the highest power conversion efficiency of 9.36% and 11.43% under 100 mW cm?2 AM1.5G solar illumination. For p-i-n cells, the standard HTM PEDOT-based cell reaches an efficiency of 12.86% under the same conditions.
- Jia, Jingwen,Duan, Liangsheng,Chen, Yu,Zong, Xueping,Sun, Zhe,Wu, Quanping,Xue, Song
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- Reactions of aniline with alkali metal diphenylketyls and dianions derived from benzophenone and Michler's ketone
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Potassium diphenylketyl and benzophenone dianion react with aniline to afford N-(diphenylmethylene) aniline. Under analogous conditions, the corresponding sodium and lithium derivatives undergo disproportionation with formation of triphenylmethanol, benzo
- Turaeva,Kurbatov
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- Accelerating Amine-Catalyzed Asymmetric Reactions by Intermolecular Cooperative Thiourea/Oxime Hydrogen-Bond Catalysis
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The ability of intermolecular cooperative thiourea/oxime hydrogen-bond catalysis for improving and accelerating asymmetric aminocatalysis is presented. The two readily available hydrogen-bond-donating catalysts operates in synergy with a chiral amine catalyst to accomplish highly stereoselective transformations. The synergistic catalyst systems simultaneously activate both electrophiles and nucleophiles, and make the transformations more chemo- and stereoselective. This was exemplified by performing co-catalytic enantioselective direct intermolecular α-alkylation reactions of aldehydes, direct aldol reactions, and asymmetric conjugate reactions, which gave the corresponding products in high yields and enantiomeric ratios.
- Afewerki, Samson,Córdova, Armando,Ibrahem, Ismail,Ma, Guangning,Zhang, Kaiheng
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supporting information
p. 3043 - 3049
(2021/07/22)
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- FLUOROGENIC AMINO ACIDS
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Provided herein are compounds (i.e., fluorogenic amino acids (FgAAs), e.g., compounds of Formulae (I), (II), (III), and (IV)) that can be used in fluorescent labeling of biomolecules (e.g., proteins) and/or cells. Also described herein are methods of labeling and detecting biomolecules and/or cells by incorporating the FgAA compounds described herein into the biomolecules and/or cells (e.g., by enzymatic incorporation). Also provided herein are biomolecules, cells, compositions, and kits comprising the FgAA compounds described herein.
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Paragraph 00290
(2021/06/22)
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- Intramolecular Hydrogen-Bonding Modulates the Nucleophilic Reactivity of Ammonium-Peroxycarboxylates
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The ammonium-peroxycarboxylic acid mesylates derived from γ-aminobutyric acid, β-alanine, and β-piperidinopropionic acid were synthesized and characterized by spectroscopic methods and X-ray crystallography. To study the nucleophilic reactivities of the corresponding ammonium- and amino-peroxycarboxylates, the kinetics of their reactions with a series of benzhydrylium ions (Ar2CH+) were investigated in alkaline, aqueous solutions at 20 °C. Using sequential-mixing stopped-flow UV/Vis photometry, the rates of the reactions of the short-lived nucleophiles with Ar2CH+ were determined and analyzed by the linear free energy relationship lg k = sN(N + E) furnishing nucleophilicity parameters (N, sN) of the peroxycarboxylates. Quantum chemical calculations indicate that the reactivity of the zwitterionic ammonium-peroxycarboxylates is attenuated by intramolecular N–H···O hydrogen bonding.
- Mayer, Robert J.,Ofial, Armin R.
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supporting information
p. 6010 - 6017
(2018/11/10)
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- Hydrogenation of Carbonyl Derivatives with a Well-Defined Rhenium Precatalyst
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The first efficient and general rhenium-catalyzed hydrogenation of carbonyl derivatives was developed. The key to the success of the reaction was the use of a well-defined rhenium complex bearing a tridentate diphosphinoamino ligand as the catalyst (0.5 mol %) at 70 °C in the presence of H2 (30 bar). The mechanism of the reaction was investigated by DFT(PBE0-D3) calculations.
- Wei, Duo,Roisnel, Thierry,Darcel, Christophe,Clot, Eric,Sortais, Jean-Baptiste
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- Selective detection of nerve agent simulants by using triarylmethanol-based chromogenic chemodosimeters
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A family of triarylcarbinols 1-11 has been synthesised, and the chromogenic behaviour of the members in the presence of nerve-agent simulants diethylcyanophosphonate (DCNP) and diisopropylfluorophosphate (DFP) in acetonitrile and in buffered mixed water/acetonitrile solutions has been investigated. Hydrophobic polyethylene oxide films of these compounds have been prepared. Some of these triarylcarbinols act as OFF/ON chemodosimeters for the nerve agent simulants. The sensing mechanism includes phosphorylation of the hydroxyl group in the triarylcarbinol derivatives, followed by a dephosphatation reaction induced by the electron-donor groups present in the structure. The existence of additional tert-butyldimethylsilyl ether groups in compounds 2 and 3 permits these reagents to act as double probes by allowing selective signalling of DFP. The reactivity between 1 and 4-6 with DFP and DCNP in acetonitrile or water/acetonitrile solutions under pseudo first-order kinetic conditions was studied to determine rate constants (k) and the half-life times (t1/2) for the corresponding reactions. Films containing compound 2 were used to detect simulants both in solution and in the vapour phase. Finally, a logic device was designed that incorporated compounds 2, 14, and 15 that allowed detection of DFP (a Sarin and Soman simulant) and DCNP (a Tabun simulant), even in the presence of possible interferents such as acids. Triarylmethanol derivatives as visual OFF/ON chromodosimeters of nerve-agent simulants (DCNP and DFP), even in water/acetonitrile (3:1 v/v) solutions, were investigated. The developed compounds were able to act as double probe systems and allowed the selective signalling of DFP. Films of compound 2 were used to detect the simulants in solution and in the vapour phase. Copyright
- Costero, Ana M.,Parra, Margarita,Gil, Salvador,Gotor, Raul,Martinez-Manez, Ramon,Sancenon, Felix,Royo, Santiago
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p. 4937 - 4946,10
(2020/08/24)
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- Chemo-and stereoselective iron-catalyzed hydrosilylation of ketones
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The reduction of ketones with polymethylhydrosiloxane (PMHS) gives the corresponding alcohols in good to excellent yield applying iron-based catalyst systems. In the case of prochiral ketones, the use of Fe(OAc) 2/(S,S)-Me-DuPhos leads to high enantioselectivity up to 99% ee. The reaction proceeds in the presence of several functional groups such as esters, halides as well as conjugated double bonds, with high chemoselectivity. The advantage of this protocol is that the reaction requires no activating agents or additives.
- Addis, Daniele,Shaikh, Nadim,Zhou, Shaolin,Das, Shoubhik,Junge, Kathrin,Beller, Matthius
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experimental part
p. 1687 - 1691
(2011/08/05)
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- Asymmetric SN 1 α-Alkylation of cyclic ketones catalyzed by functionalized chiral ionic liquid (FCIL) organocatalysts
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Ionic liquid works better: The first intermolecular asymmetric α-alkylation of cyclic ketones was realized by using functionalized chiral ionic liquids as catalysts. The reaction proceeded with good to excellent yields and high ee. Highly stereoselective desymmetrization of 4-substituted cyclohexanones with >99:1 d.r. and up to 87 % ee were achieved by using this protocol. (Chemical Equation Representation).
- Zhang, Long,Cui, Lingyun,Li, Xin,Li, Jiuyuan,Luo, Sanzhong,Cheng, Jin-Pei
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supporting information; experimental part
p. 2045 - 2049
(2010/06/15)
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- New chelating stilbazonium-like dyes from Michler's ketone
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(Chemical Equation Presented) A series of "push-pull" salts substituted with an electron-donating bis(N,N-dimethyl)aniline unit and different electron-withdrawing methyl or chelating pyridinium units have been designed and synthesized from Michler's ketone. The spectroscopic and electronic properties were investigated and compared to their DAST homologues. The studies revealed that a lower HOMO-LUMO gap is obtained in all cases, showing the ability of our donor to increase the "push-pull" effect. Two chromophores with a terpyridine as acceptor end group have also been prepared.
- Dumur, Frederic,Mayer, Cedric R.,Dumas, Eddy,Miomandre, Fabien,Frigoli, Michel,Secheresse, Francis
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p. 321 - 324
(2008/09/19)
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- Solvent Nucleophilicity
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The rates of the reactions of benzhydrylium ions (diarylcarbenium ions) with solvent mixtures of variable composition (water/acetonitrile, methanol/acetonitrile, ethanol/acetonitrile, ethanol/water, and trifluoroethanol/water) have been determined photometrically by conventional UV-vis spectroscopy, stopped-flow methods, and laser flash techniques. It has been shown that the first-order rate constants follow the previously published relationship log k(20°C) = s(N+E), where E is an empirical electrophilicity parameter, N is an empirical nucleophilicity parameter, and s is a nucleophile-specific slope parameter. From plots of log k versus E of the benzhydrylium ions are derived the solvent nucleophilicity parameters s and N, the latter of which are designated as N1 to emphasize that their use in the quoted correlation equation gives rise to first-order rate constants. A linear correlation between N1 and Kevill's solvent nucleophilicity NT based on S-methyldibenzothiophenium ions is reported, which allows one to interconvert the two sets of data. Because the N1 values are directly comparable to the previously reported nucleophilicity parameters N for π-systems (www.cup.uni-muenchen.de/oc/mayr/), the systematic design of Friedel-Crafts reactions with solvolytically generated carbocations becomes possible.
- Minegishi, Shinya,Kobayashi, Shinjiro,Mayr, Herbert
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p. 5174 - 5181
(2007/10/03)
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- A study on equilibrium and kinetics of carbocation-to-carbinol conversion for di- and tri- arylmethane dye cations in aqueous solutions: Relative stabilities of dye carbocations and mechanism of dye carbinol formation
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Arylmethane dye cations form a structurally interesting set of stable carbocations. A detailed study on rate-equilibria of carbinol formation from two diarylmethane and nine triarylmethane dye carbocations in aqueous solutions has been carried out using spectrophotometric measurements. The conclusions reached are : (i) The stability order found (auramine O>crystal violet = methyl violet > victoria blue R > victoria pure blue BO = ethyl violet > pararosaniline > brilliant green > malachite green > carbocation form of Michler's hydrol > methyl green), seems to be determined by an interplay of dye carbocation / carbinol conformation and stereoelectronic effects of substituents; and (ii) carbinol formation is general base catalysed and occurs by the rate determining attack of a H2O molecule on the dye carbocation centre via two kinetic pathways one mediated by another H2O molecule and the other by a OH ion.
- Sen Gupta,Mishra,Radha Rani
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p. 703 - 708
(2007/10/03)
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- A Reinvestigation of the Meerwein-Ponndorf-Verley Reduction: A Highly Efficient Variation Using Zirconium Catalysts
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A new variation of the Meerwein-Ponndorf-Verley reduction based on mechanistic considerations is presented.Under optimized conditions 1-(4-dimethylaminophenyl)ethanol was used as the reducing alcohol (2-4 equiv.), Zr(O-tBu)4 as the catalyst (0.2 equiv.), and toluene or cyclohexane as the solvent.Aldehydes and ketones (if not extremely sterically hindered) were reduced to the corresponding alcohols at room temperature mostly within 2-4 h in essentially quantitative yield. α,β-Unsaturated carbonyl compounds cleanly react in a 1,2-mode to afford the corresponding allylic alcohols. - Key Words: Reductions / Meerwein-Ponndorf-Verley reaction / Catalysis / Zirconium tetra-tert-butoxide / β-Hydride shift / Kinetics
- Knauer, Birgit,Krohn, Karsten
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p. 677 - 684
(2007/10/02)
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