606-87-1Relevant academic research and scientific papers
Hydroborative reduction of amides to amines mediated by La(CH2C6H4NMe2-: O)3
Gong, Mingliang,Guo, Chenjun,Luo, Yunjie,Xie, Hongzhen,Zhang, Fangcao
, p. 779 - 791 (2022/01/22)
The deoxygenative reduction of amides to amines is a great challenge for resonance-stabilized carboxamide moieties, although this synthetic strategy is an attractive approach to access the corresponding amines. La(CH2C6H4NMe2-o)3, a simple and easily accessible lanthanide complex, was found to be highly efficient not only for secondary and tertiary amide reduction, but also for the most challenging primary reduction with pinacolborane. This protocol exhibited good tolerance for many functional groups and heteroatoms, and could be applied to gram-scale synthesis. The active species in this catalytic cycle was likely a lanthanide hydride.
Regioselective Synthesis of 2° Amides Using Visible-Light-Induced Photoredox-Catalyzed Nonaqueous Oxidative C-N Cleavage of N, N-Dibenzylanilines
Neerathilingam, Nalladhambi,Bhargava Reddy, Mandapati,Anandhan, Ramasamy
supporting information, p. 15117 - 15127 (2021/10/25)
A visible-light-driven photoredox-catalyzed nonaqueous oxidative C-N cleavage of N,N-dibenzylanilines to 2° amides is reported. Further, we have applied this protocol on 2-(dibenzylamino)benzamide to afford quinazolinones with (NH4)2S2O8 as an additive. Mechanistic studies imply that the reaction might undergo in situ generation of α-amino radical to imine by C-N bond cleavage followed by the addition of superoxide ion to form amides.
Method for catalyzing hydrodesulfurization of thioamide derivative
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Paragraph 0064-0068, (2021/07/09)
The invention provides a method for catalyzing hydrodesulfurization of a thioamide derivative, which comprises the following steps: sequentially adding a pentacarbonyl manganese bromide catalyst, a reaction substrate thioamide derivative, Lewis acid, a solvent and alkali into a polytetrafluoroethylene lined reaction tube, putting the reaction tube into a high-pressure kettle, introducing hydrogen to carry out catalytic hydrogenation reaction, cooling to room temperature, discharging gas, washing the reaction tube with ethyl acetate, passing through a silica gel small short column, carrying out spin drying, and carrying out column chromatography purification to obtain a target product. The monovalent manganese which is low in toxicity and good in chemical selectivity and biocompatibility is used as the catalyst to catalyze hydrodesulfurization of the thioamide derivative, the substrate range is wide, the yield of amine is high, and the method has high drug synthesis application value.
Reduction of Amides to Amines with Pinacolborane Catalyzed by Heterogeneous Lanthanum Catalyst La(CH2C6H4NMe2- o)3@SBA-15
Guo, Chenjun,Zhang, Fangcao,Yu, Chong,Luo, Yunjie
supporting information, p. 13122 - 13135 (2021/08/31)
Hydroboration of amides is a useful synthetic strategy to access the corresponding amines. In this contribution, it was found that the supported lanthanum benzyl material La(CH2C6H4NMe2-o)3@SBA-15 was highly active for the hydroboration of primary, secondary, and tertiary amides to amines with pinacolborane. These reactions selectively produced target amines and showed good tolerance for functional groups such as -NO2, -halogen, and -CN, as well as heteroatoms such as S and O. This reduction procedure exhibited the recyclable and reusable property of heterogeneous catalysts and was applicable to gram-scale synthesis. The reaction mechanisms were proposed based on some control experiments and the previous literature. This is the first example of hydroborative reduction of amides to amines mediated by heterogeneous catalysts.
BF3·Et2O as a metal-free catalyst for direct reductive amination of aldehydes with amines using formic acid as a reductant
Fan, Qing-Hua,Liu, Xintong,Luo, Zhenli,Pan, Yixiao,Xu, Lijin,Yang, Ji,Yao, Zhen,Zhang, Xin
supporting information, p. 5205 - 5211 (2021/07/29)
A versatile metal- and base-free direct reductive amination of aldehydes with amines using formic acid as a reductant under the catalysis of inexpensive BF3·Et2O has been developed. A wide range of primary and secondary amines and diversely substituted aldehydes are compatible with this transformation, allowing facile access to various secondary and tertiary amines in high yields with wide functional group tolerance. Moreover, the method is convenient for the late-stage functionalization of bioactive compounds and preparation of commercialized drug molecules and biologically relevant N-heterocycles. The procedure has the advantages of simple operation and workup and easy scale-up, and does not require dry conditions, an inert atmosphere or a water scavenger. Mechanistic studies reveal the involvement of imine activation by BF3and hydride transfer from formic acid.
Benzyne-Mediated Esterification Reaction
Li, Yang,Shi, Jiarong,Zhao, Jinlong
supporting information, p. 7274 - 7278 (2021/10/01)
A benzyne-mediated esterification of carboxylic acids and alcohols under mild conditions has been realized, which is made possible via a selective nucleophilic addition of carboxylic acid to benzyne in the presence of alcohol. After a subsequent transesterification with alcohol, the corresponding esters can be produced efficiently. This benzyne-mediated protocol can be used on the modification of Ibuprofen, cholesterol, estradiol, and synthesis of nandrolone phenylpropionate. In addition, benzyne can also be used to promote lactonization and amidation reaction.
Transition-Metal-Free and Base-Promoted Carbon-Heteroatom Bond Formation via C-N Cleavage of Benzyl Ammonium Salts
Liu, Long,Tang, Yuanyuan,Wang, Kunyu,Huang, Tianzeng,Chen, Tieqiao
, p. 4159 - 4170 (2021/03/09)
A facile and general method for constructing carbon-heteroatom (C-P, C-O, C-S, and C-N) bonds via C-N cleavage of benzyl ammonium salts under transition-metal-free conditions was reported. The combination of t-BuOK and 18-crown-6 enabled a wide range of substituted benzyl ammonium salts to couple readily with different kinds of heteroatom nucleophiles, i.e. hydrogen phosphoryl compounds, alcohols, thiols, and amines. Good functional group tolerance was demonstrated. The scale-up reaction and one-pot synthesis were also successfully performed.
Direct benzylation of amines with benzylic alcohols catalyzed by palladium/phosphine-borane catalyst system
Onodera, Gen,Kumagae, Hidenobu,Nakamura, Daiki,Hayasaki, Takuto,Fukuda, Tsutomu,Kimura, Masanari
supporting information, (2020/11/04)
Direct catalytic benzylation of amines with benzylic alcohols to give benzylamines has been newly developed by using palladium/phosphine-borane catalyst system. In this catalytic reaction, the linking between both phosphine and borane moieties in the ligand is very important. Hydroxy group of benzylic alcohols is activated by Lewis acidic borane to form a benzylpalladium intermediate which is attacked by amines to give benzylamine products.
Ultrasound-assisted construction of a Z-scheme heterojunction with g-C3N4 nanosheets and flower-like Bi2WO6 microspheres and the photocatalytic activity in the coupling reaction between alcohols and amines under visible light irradiation
Hao, Xueli,Li, Enbo,Li, Haiying,Li, Jingyi,Wang, Yan,Wang, Zhibao,Yu, Xiujuan,Zhang, Zhiying
, (2020/07/25)
Flower-like Bi2WO6 microspheres and bulk g-C3N4 were prepared by the hydrothermal method and high-temperature calcining method, respectively. A new method based on the combination of ultrasonic stripping and mechanical stirring was used to obtain uniform composite x-Bi2WO6/g-C3N4 (x is the Bi2WO6 mass ratio) photocatalysts with a Z-scheme heterojunction. In the reaction of benzyl alcohol and aniline to form imine, the optimal composite, 30percent-Bi2WO6/g-C3N4, showed a conversion rate of 87.6percent, which is much higher than that of pure Bi2WO6 and g-C3N4. Characterization by SEM and TEM showed that the ultrasonically stripped g-C3N4 significantly reduced the radial dimension compared to bulk g-C3N4. A uniformly dispersed photocatalytic material was formed, and it maintained a flower-like microsphere structure. Materials characterized by N2 adsorption–desorption isotherms (BET) showed that the specific surface area of the g-C3N4 nanosheets increased by approximately ten times after ultrasonic stripping. The photostability of the composite was verified by cyclic experiments. Under visible light irradiation, the activation energy of the coupling reaction between benzyl alcohol and aniline was found to be decreased by 29.8 kJ mol?1. A capture experiment was used to verify the active species in the photocatalytic system, with the reaction found to be mainly completed through the synergistic action of h+, e? and ?O2?.
ROMP-Boranes as Moisture-Tolerant and Recyclable Lewis Acid Organocatalysts
Vidal, Fernando,McQuade, James,Lalancette, Roger,J?kle, Frieder
supporting information, p. 14427 - 14431 (2020/10/13)
Although widely used in catalysis, the multistep syntheses and high loadings typically employed are limiting broader implementation of highly active tailor-made arylborane Lewis acids and Lewis pairs. Attempts at developing recyclable systems have thus far met with limited success, as general and versatile platforms are yet to be developed. We demonstrate a novel approach that is based on the excellent control and functional group tolerance of ring-opening metathesis polymerization (ROMP). The ROMP of highly Lewis acidic borane-functionalized phenylnorbornenes afforded both a soluble linear copolymer and a cross-linked organogel. The polymers proved highly efficient as recyclable catalysts in the reductive N-alkylation of arylamines under mild conditions and at exceptionally low catalyst loadings. The modular design presented herein can be readily adapted to other finely tuned triarylboranes, enabling wide applications of ROMP-borane polymers as well-defined supported organocatalysts.
