72920-03-7Relevant articles and documents
Additive-freeN-methylation of amines with methanol over supported iridium catalyst
Liu, Xiang,Loh, Teck-Peng,Qiang, Wenwen,Wang, Jing,Ye, Sen,Zhu, Longfei
, p. 3364 - 3375 (2021/06/06)
An efficient and versatile zinc oxide-supported iridium (Ir/ZnO) catalyst was developed to catalyze the additive-freeN-methylation of amines with methanol. Mechanistic studies suggested that the high catalytic reactivity is rooted in the small sizes (1.4 nm) of Ir nanoparticles and the high ratio (93%) of oxidized iridium species (IrOx, Ir3+and Ir4+) on the catalyst. Moreover, the delicate cooperation between the IrOxand ZnO support also promoted its high reactivity. The selectivity of this catalyticN-methylation was controllable between dimethylation and monomethylation by carefully tuning the catalyst loading and reaction solvent. Specifically, neat methanol with high catalyst loading (2 mol% Ir) favored the formation ofN,N-dimethylated amine, while the mesitylene/methanol mixture with low catalyst loading (0.5 mol% Ir) was prone to producing mono-N-methylated amines. An environmentally benign continuous flow system with a recycled mode was also developed for the efficient production ofN-methylated amines. With optimal flow rates and amine concentrations, a variety ofN-methylamines were produced with good to excellent yields in this Ir/ZnO-based flow system, providing a starting point for the clean and efficient production ofN-methylamines with this cost-effective chemical process.
A Metal-Free Direct Arene C?H Amination
Wang, Tao,Hoffmann, Marvin,Dreuw, Andreas,Hasagi?, Edina,Hu, Chao,Stein, Philipp M.,Witzel, Sina,Shi, Hongwei,Yang, Yangyang,Rudolph, Matthias,Stuck, Fabian,Rominger, Frank,Kerscher, Marion,Comba, Peter,Hashmi, A. Stephen K.
supporting information, p. 2783 - 2795 (2021/04/05)
The synthesis of aryl amines via the formation of a C?N bond is an essential tool for the preparation of functional materials, active pharmaceutical ingredients and bioactive products. Usually, this chemical connection is only possible by transition metal-catalyzed reactions, photochemistry or electrochemistry. Here, we report a metal-free arene C?H amination using hydroxylamine derivatives under benign conditions. A charge transfer interaction between the aminating reagents TsONHR and the arene substrates enables the chemoselective amination of the arene, even in the presence of various functional groups. Oxygen was crucial for an effective conversion and its accelerating role for the electron transfer step was proven experimentally. In addition, this was rationalized by a theoretical study which indicated the involvement of a dioxygen-bridged complex with a “Sandwich-like” arrangement of the aromatic starting materials and the aminating agents at the dioxygen molecule. (Figure presented.).
Selective N -monomethylation of primary anilines with the controllable installation of N -CH2D, N -CHD2, and N -CD3units
Meng, Jing,Wang, Yi-Feng,Wang, Zhijuan,Xia, Hui-Min,Xu, Ai-Qing,Zhang, Feng-Lian
supporting information, p. 4922 - 4926 (2020/07/30)
The selective N-monomethylation of primary anilines was realized by the use of the Me3N-BH3/N,N-dimethylformamide (DMF) system as the methyl source. This method also allows for the controllable introduction of N-CH2D, N-CHD2, and N-CD3 units with high lev
Palladium-Catalyzed Methylation of Nitroarenes with Methanol
Wang, Lin,Neumann, Helfried,Beller, Matthias
supporting information, p. 5417 - 5421 (2019/04/04)
A procedure for the synthesis of N-methyl-arylamines directly from nitroarenes using methanol as green methylating agent was developed. The key to success is the use of a specific catalyst system consisting of palladium acetate and the ligand 1-[2,6-bis(isopropyl)phenyl]-2-[tert-butyl(2-pyridinyl)phosphino]-1H-Imidazole (L1). The generality of this protocol is demonstrated in the synthesis of more than 20 N-methyl-arylamines under comparably mild conditions. Combining this novel methodology with subsequent coupling processes using the same catalyst allows for efficient diversification of aromatic nitro compounds to a broad variety of amines including drug molecules.
Selective Monomethylation of Amines with Methanol as the C1 Source
Choi, Geunho,Hong, Soon Hyeok
supporting information, p. 6166 - 6170 (2018/04/30)
The N-monomethyl functionality is a common motif in a variety of synthetic and natural compounds. However, facile access to such compounds remains a fundamental challenge in organic synthesis owing to selectivity issues caused by overmethylation. To address this issue, we have developed a method for the selective, catalytic monomethylation of various structurally and functionally diverse amines, including typically problematic primary aliphatic amines, using methanol as the methylating agent, which is a sustainable chemical feedstock. Kinetic control of the aliphatic amine monomethylation was achieved by using a readily available ruthenium catalyst at an adequate temperature under hydrogen pressure. Various substrates including bio-related molecules and pharmaceuticals were selectively monomethylated, demonstrating the general utility of the developed method.
Introduction of the 4,4,4-Trifluorobut-2-ene Chain Exploiting a Regioselective Tsuji-Trost Reaction Catalyzed by Palladium Nanoparticles
Hemelaere, Rémy,Desroches, Justine,Paquin, Jean-Fran?ois
supporting information, p. 1770 - 1773 (2015/04/14)
A palladium-nanoparticle-catalyzed Tsuji-Trost reaction of 4,4,4-trifluorobut-2-en-1-yl acetate and ethyl(4,4,4-trifluorobut-2-en-1-yl)carbonate was accomplished with various nucleophiles including phenols, amines, and malonates. In the case of the phenols, isomerization of the double bond in the product (up to 20%) was observed as a side reaction. Further synthetic transformations including hydrogenation, the Diels-Alder reaction, and asymmetric dihydroxylation of a product were also examined.
Dual protonophore-chitinase inhibitors dramatically affect O. Volvulus molting
Gooyit, Major,Tricoche, Nancy,Lustigman, Sara,Janda, Kim D.
, p. 5792 - 5799 (2014/08/05)
The L3-stage-specific chitinase OvCHT1 has been implicated in the development of Onchocerca volvulus, the causative agent of onchocerciasis. Closantel, a known anthelmintic drug, was previously discovered as a potent and specific OvCHT1 inhibitor. As closantel is also a known protonophore, we performed a simple scaffold modulation to map out the structural features that are relevant for its individual or dual biochemical roles. Furthermore, we present that either OvCHT1 inhibition or protonophoric activity was capable of affecting O. volvulus L3 molting and that the presence of both activities in a single molecule yielded more potent inhibition of the nematode's developmental process.
N-Demethylation of N,N-Dimethylanilines by the benzotriazole N-Oxyl radical: Evidence for a two-step electron transfer-proton transfer mechanism
Baciocchi, Enrico,Bietti, Massimo,Lanzalunga, Osvaldo,Lapi, Andrea,Raponi, Daniele
supporting information; experimental part, p. 1378 - 1385 (2010/06/11)
"Chemical Equation Presented" The reaction of the benzotriazole N-oxyl radical (BTNO) with a series of 4-X-N,N-dimethylanilines (X = CN, CF 3, CO2CH2CH3, CH3, OC6H5, OCH3) has been investigated in CH 3CN. Product analysis shows that the radical, 4-X-C6H 4N(CH3)CH2·, is first formed, which can lead to the N-demethylated product or the product of coupling with BTNO. Reaction rates were found to increase significantly by increasing the electron-donating power of the aryl substituents (p+ = -3.8). With electron-donating substituents (X = CH3, OC6H5, OCH3), no intermolecular deuterium kinetic isotope effect (DKIE) and a substantial intramolecular DKIE are observed. With electron-withdrawing substituents (X = CN, CF3, CO2CH2CH 3), substantial values of both intermolecular and intramolecular DKIEs are observed. These results can be interpreted on the basis of an electron-transfer mechanism from the N,N-dimethylanilines to the BTNO radical followed by deprotonation of the anilinium radical cation (ET-PT mechanism). By applying the Marcus equation to the kinetic data for X = CH3, OC 6H5, OCH3 (rate-determining ET), a reorganization energy for the ET reaction was determined (λ BTNO/DMA= 32.1 kcal mol- 1). From the self-exchange reorganization energy for the BTNO/BTNO- couple, a self-exchange reorganization energy value of 31.9 kcal mol-1 was calculated for the DMA·+/DMA couple.
Design and synthesis of novel dihydroquinoline-3-carboxylic acids as HIV-1 integrase inhibitors
Sechi, Mario,Rizzi, Giuseppe,Bacchi, Alessia,Carcelli, Mauro,Rogolino, Dominga,Pala, Nicolino,Sanchez, Tino W.,Taheri, Laleh,Dayam, Raveendra,Neamati, Nouri
experimental part, p. 2925 - 2935 (2009/09/05)
Previously, we discovered linomide analogues as novel HIV-1 integrase (IN) inhibitors. Here, to make possible structure-activity relationships, we report on the design and synthesis of a series of substituted dihydroquinoline-3-carboxylic acids. The crystal structure of the representative compound 2c has also been solved. Among the eight new analogues, 2e showed a potency in inhibiting IN strand transfer catalytic activity similar to the reference diketo acid inhibitor L-731,988 (IC50 = 0.9 μM vs. 0.54 μM, for 2e and L-731,988, respectively). Furthermore, none of the compounds showed significant cytotoxicity in two tested cancer cell lines. These compounds represent an interesting prototype of IN inhibitors, potentially involved in a metal chelating mechanism, and further optimization is warranted.
A kinetic study of the reaction of N,N-dimethylanilines with 2,2-diphenyl-1-picrylhydrazyl Radical: A Concerted Proton-Electron Transfer?
Baciocchi, Enrico,Calcagni, Alessandra,Lanzalunga, Osvaldo
, p. 4110 - 4115 (2008/09/21)
(Chemical Equation Presented) The reactivity of the 2,2-diphenyl-1- picrylhydrazyl radical (dpph?) toward the N-methyl C-H bond of a number of 4-X-substituted-N,N-dimethylanilines (X = OMe, OPh, CH3, H) has been investigated in MeCN, in the absence and in the presence of Mg(ClO4)2, by product, and kinetic analysis. The reaction was found to lead to the N-demethylation of the N,N-dimethylaniline with a rate quite sensitive to the electron donating power of the substituent (ρ+ = -2.03). With appropriately deuterated N,N-dimethylanilines, the intermolecular and intramolecular deuterium kinetic isotope effects (DKIEs) were measured with the following results. Intramolecular DKIE [(k H/kD)intra] was found to always be similar to intermolecular DKIE [(kH/kD)inter]. These results suggest a single-step hydrogen transfer mechanism from the N-C-H bond to dpph? which might take the form of a concerted proton-electron transfer (CPET). An electron transfer (ET) step from the aniline to dpph ? leading to an anilinium radical cation, followed by a proton transfer step that produces an α-amino carbon radical, appears very unlikely. Accordingly, a rate-determining ET step would require no DKIE or at least different inter and intramolecular isotope effects. On the other hand, an equilibrium-controlled ET is not compatible with the small slope value (-0.22 kcal-1 K-1) of the log kH/ΔG° plot. Furthermore, the reactivity increases by changing the solvent to the less polar toluene whereas the reverse would be expected for an ET mechanism. In the presence of Mg2+, a strong rate acceleration was observed, but the pattern of the results remained substantially unchanged: inter and intramolecular DKIEs were again very similar as well as the substituent effects. This suggests that the same mechanism (CPET) is operating in the presence and in the absence of Mg2+. The significant rate accelerating effect by Mg2+ is likely due to a favorable interaction of the Mg2+ ion with the partial negatively charged α-methyl carbon in the polar transition state for the hydrogen transfer process.
