4107-98-6Relevant articles and documents
Substituent Effects. 7. Microscopic Dissociation Constants of 4-Amino- and 4-(Dimethylamino)benzoic Acid
Graaf, B.van de,Hoefnagel, A. J.,Wepster, B. M.
, p. 653 - 657 (1981)
The termodynamic microscopic dissociation constants of the title compounds have determined from the two macroscopic constants K1 and K2 and KA, the carboxylic acid dissociation constant of the cation.The latter were calculated by starting from the experimental value for 4-(trimethylammonio)benzoic acid using our knowledge of the substituent effects of charged substituents.In water, the zwitterion equilibrium contains 10.5percent zwitterion for 4-aminobenzoic acid and 19.4percent for 4-(dimethylamino)benzoic acid.In 50percent and 75percent ethanol the zwitterion content is very low.Extended Hine equations are applied to show the contributions of the several substituent interactions in the individual species, and to predict the percent zwitterion in other acids.Glycine is also discussed.In water, ?-4-NH2 = -0.62 and ?-4-NMe2 = -0.69; the latter value is rather different from that commonly tabulated.
Desymmetric enantioselective reduction of cyclic 1,3-diketones catalyzed by a recyclable p-chiral phosphinamide organocatalyst
Qin, Xu-Long,Li, Ang,Han, Fu-She
supporting information, p. 2994 - 3002 (2021/03/01)
The P-stereogenic phosphinamides are a structurally novel skeletal class which has not been investigated as chiral organocatalysts. However, chiral cyclic 3-hydroxy ketones are widely used as building blocks in the synthesis of natural products and bioactive compounds. However, general and practical methods for the synthesis of such chiral compounds remain underdeveloped. Herein, we demonstrate that the P-stereogenic phosphinamides are powerful organocatalysts for the desymmetric enantioselective reduction of cyclic 1,3-diketones, providing a useful method for the synthesis of chiral cyclic 3-hydroxy ketones. The protocol displays a broad substrate scope that is amenable to a series of cyclic 2,2-disubstituted five- and six-membered 1,3-diketones. The chiral cyclic 3-hydroxy ketone products bearing an all-carbon chiral quaternary center could be obtained with high enantioselectivities (up to 98% ee) and diastereoselectivities (up to 99:1 dr). Most importantly, the reactions could be practically performed on the gram scale and the catalysts could be reused without compromising the catalytic efficiency. Mechanistic studies revealed that an intermediate formed from P-stereogenic phosphinamide and catecholborane is the real catalytically active species. The results disclosed herein bode well for designing and developing other reactions using P-stereogenic phosphinamides as new organocatalysts.
Preparation method of N-alkylated derivative of primary amine compound
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Paragraph 0021; 0057, (2021/07/09)
The invention relates to a preparation method of an N-alkylated derivative of a primary amine compound. The method comprises the following steps: uniformly mixing a primary amine compound, an alcohol compound and a catalyst in a reactor, and heating to react for a period of time to generate an N-alkylated substituted tertiary amine compound; wherein the catalyst is a copper-cobalt bimetallic catalyst, and the carrier of the catalyst is Al2O3. According to the method, alcohol is adopted as an alkylating reagent and is low in price and easy to obtain, a byproduct is water, no pollution is caused to the environment, and the overall reaction atom economy is high; the catalyst is simple in preparation method, low in cost, high in reaction activity and good in structural stability; meanwhile, by using the copper-cobalt bimetallic catalyst, the use of strong base additives can be avoided, and the requirement on reaction equipment is low; and the reaction post-treatment is convenient, and the catalyst can be recycled and is environment-friendly.
C–N Cross-coupling Reactions of Amines with Aryl Halides Using Amide-Based Pincer Nickel(II) Catalyst
Albkuri, Yahya M.,RanguMagar, Ambar B.,Brandt, Andrew,Wayland, Hunter A.,Chhetri, Bijay P.,Parnell, Charlette M.,Szwedo, Peter,Parameswaran-Thankam, Anil,Ghosh, Anindya
, p. 1669 - 1678 (2019/12/27)
Abstract: An approach to C–N cross-coupling reactions of aryl halides with amines in the presence of an amide-based pincer nickel(II) catalyst (2) is described. For 3?h reactions at 110?°C with 0.2?mol% catalyst, aryl bromides gave higher turnover numbers (TON) than the corresponding chlorides or iodides. Both primary and secondary amines could be used with the former giving higher TON. However, sterically hindered amines showed lower TON. In elucidating the mechanism of this nickel complex-catalyzed C–N cross coupling reaction it was found that the rate of reaction was unchanged in the presence of radical quenchers and a plausible Ni(I)–Ni(III) pathway is proposed. Graphic Abstract: [Figure not available: see fulltext.]Nickel pincer catalyst proved to be excellent catalyst for the C-N cross-coupling reaction with the high turnover number (TON) for 1° and 2° amines and different nonactivated aryl halides under optimum conditions.
N-Arylphenothiazines as strong donors for photoredox catalysis – pushing the frontiers of nucleophilic addition of alcohols to alkenes
Speck, Fabienne,Rombach, David,Wagenknecht, Hans-Achim
supporting information, p. 52 - 59 (2019/01/28)
A new range of N-phenylphenothiazine derivatives was synthesized as potential photoredox catalysts to broaden the substrate scope for the nucleophilic addition of methanol to styrenes through photoredox catalysis. These N-phenylphenothiazines differ by their electron-donating and electron-withdrawing substituents at the phenyl group, covering both, σ and π-type groups, in order to modulate their absorbance and electrochemical characteristics. Among the synthesized compounds, alkylaminylated N-phenylpheno-thiazines were identified to be highly suitable for photoredox catalysis. The dialkylamino substituents of these N-phenylpheno-thiazines shift the estimated excited state reduction potential up to ?3.0 V (vs SCE). These highly reducing properties allow the addition of methanol to α-methylstyrene as less-activated substrate for this type of reaction. Without the help of an additive, the reaction conditions were optimized to achieve a quantitative yield for the Markovnivkov-type addition product after 20 h of irradiation.
Photoinduced Cross-Coupling of Amines with 1,2-Diiodobenzene and Its Application in the Synthesis of Carbazoles
Zhao, Xinxin,Chen, Ming,Huang, Binbin,Yang, Chao,Gao, Yuan,Xia, Wujiong
, p. 2981 - 2989 (2018/05/15)
A facile and efficient process for the preparation of various tertiary aminobenzenes and carbazole derivatives via photoinduced cross-coupling of amines with 1,2-diiodobenzene is reported. Mechanistic investigations indicate that the transformation proceeds via nucleo-philic addition of an amine to the benzyne intermediate accompanied with a proton transfer process, followed by an oxidative cyclization of the generated diphenylamine to furnish the corresponding carbazole products.
Energy Gap between the Poly-p-phenylene Bridge and Donor Groups Controls the Hole Delocalization in Donor-Bridge-Donor Wires
Wang, Denan,Talipov, Marat R.,Ivanov, Maxim V.,Rathore, Rajendra
supporting information, p. 16337 - 16344 (2016/12/27)
Poly-p-phenylene wires are critically important as charge-transfer materials in photovoltaics. A comparative analysis of a series of poly-p-phenylene (RPPn) wires, capped with isoalkyl (iAPPn), alkoxy (ROPPn), and dialkylamino (R2NPPn) groups, shows unexpected evolution of oxidation potentials, i.e., decrease (-260 mV) for iAPPn, while increase for ROPPn (+100 mV) and R2NPPn (+350 mV) with increasing number of p-phenylenes. Moreover, redox/optical properties and DFT calculations of R2NPPn/R2NPPn+? further show that the symmetric bell-shaped hole distribution distorts and shifts toward one end of the molecule with only 4 p-phenylenes in R2NPPn+?, while shifting of the hole occurs with 6 and 8 p-phenylenes in ROPPn+? and iAPPn+?, respectively. Availability of accurate experimental data on highly electron-rich dialkylamino-capped R2NPPn together with ROPPn and iAPPn allowed us to demonstrate, using our recently developed Marcus-based multistate model (MSM), that an increase of oxidation potentials in R2NPPn arises due to an interplay between the electronic coupling (Hab) and energy difference between the end-capped groups and bridging phenylenes (Δ?). A comparison of the three series of RPPn with varied Δ? further demonstrates that decrease/increase/no change in oxidation energies of RPPn can be predicted based on the energy gap Δ? and coupling Hab, i.e., decrease if Δ? ab (i.e., iAPPn), increase if Δ? > Hab (i.e., R2NPPn), and minimal change if Δ? ≈ Hab (i.e., ROPPn). MSM also reproduces the switching of the nature of electronic transition in higher homologues of R2NPPn+? (n ≥ 4). These findings will aid in the development of improved models for charge-transfer dynamics in donor-bridge-acceptor systems.
A Bis(silylene)-Substituted ortho-Carborane as a Superior Ligand in the Nickel-Catalyzed Amination of Arenes
Zhou, Yu-Peng,Raoufmoghaddam, Saeed,Szilvási, Tibor,Driess, Matthias
supporting information, p. 12868 - 12872 (2016/10/04)
The synthesis and structure of the first 1,2-bis(NHSi)-substituted ortho-carborane [(LSi:)C]2B10H10(termed SiCCSi) is reported (NHSi=N-heterocyclic silylene; L=PhC(NtBu)2). Its suitability to serve as a reliable bis(silylene) chelating ligand for transition metals is demonstrated by the formation of [SiCCSi]NiBr2and [SiCCSi]Ni(CO)2complexes. The CO stretching vibration modes of the latter indicate that the SiIIatoms in the SiCCSi ligand are even stronger σ donors than the PIIIatoms in phosphines and CIIatoms in N-heterocyclic carbene (NHC) ligands. Moreover, the strong donor character of the [SiCCSi] ligand enables [SiCCSi]NiBr2to act as an outstanding precatalyst (0.5 mol % loading) in the catalytic aminations of arenes, surpassing the activity of previously known molecular Ni-based precatalysts (1–10 mol %).
Copper-Catalyzed Electrophilic Amination of Organoaluminum Nucleophiles with O -Benzoyl Hydroxylamines
Zhou, Shuangliu,Yang, Zhiyong,Chen, Xu,Li, Yimei,Zhang, Lijun,Fang, Hong,Wang, Wei,Zhu, Xiancui,Wang, Shaowu
supporting information, p. 6323 - 6328 (2015/06/30)
A copper-catalyzed electrophilic amination of aryl and heteroaryl aluminums with N,N-dialkyl-O-benzoyl hydroxylamines that affords the corresponding anilines in good yields has been developed. The catalytic reaction proceeds very smoothly under mild conditions and exhibits good substrate scope. Moreover, the developed catalytic system is also well suited for heteroaryl aluminum nucleophiles, providing facile access to heteroaryl amines.
Donor-acceptor (D-A)-substituted polyyne chromophores: Modulation of their optoelectronic properties by varying the length of the acetylene spacer
Stefko, Martin,Tzirakis, Manolis D.,Breiten, Benjamin,Ebert, Marc-Olivier,Dumele, Oliver,Schweizer, W. Bernd,Gisselbrecht, Jean-Paul,Boudon, Corinne,Beels, Marten T.,Biaggio, Ivan,Diederich, Francois
supporting information, p. 12693 - 12704 (2013/10/01)
A series of donor-acceptor-substituted alkynes, 2 a-f, was synthesized in which the length of the π-conjugated polyyne spacer between the N,N-diisopropylanilino donor and the 1,1,4,4-tetracyanobuta-1,3-diene (TCBD) acceptor was systematically changed. The
