- Isomorphism of chiral ammonium salts Ph(All)N+Et(Me)X-·CHCl3
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The title ammonium salts (X = Br, I) were synthesized, the identity of crystal structures for them (space groups P212121, Z = 4) was found, spontaneous resolution of Ph(All)N+Et(Me)Br-·CHCl3 was performed, and the impossibility of replacement of the solvate molecule by CHBr3 or CH2Hal2 (Hal = Cl, Br, I) was demonstrated by 1H NMR and X-ray diffraction studies.
- Kostyanovsky, Remir G.,Lyssenko, Konstantin A.,Krutius, Oleg N.,Kostyanovsky, Vasily R.
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Read Online
- Catalyst-free photoinduced selective oxidative C(sp3)-C(sp3) bond cleavage in arylamines
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Due to the directional nature of sp3-hybridized orbitals and the absence of π-orbitals, the oxidative cleavage of the kinetically and thermodynamically stable C(sp3)-C(sp3) bond is extremely difficult and remains scarcely explored. In this work, under the double argument of quantum mechanics (QM) computations and meticulous experiments on our well-designed C-C single bond cleavage mechanism, we discovered a means of photoinduced selective oxidative C(sp3)-C(sp3) bond cleavage in arylamines, easily achieved by simple visible light irradiation using O2as a benign oxidant under very mild conditions. The utility of our methodology was demonstrated by the C(sp3)-C(sp3) bond cleavage in morpholine/piperazine arylamines with excellent functional group tolerance. Importantly, our methodology is noteworthy, not only in that it does not require any catalysts, but also in that it provides valuable possibilities for the scalable functionalization of clinical drugs and natural products.
- Duan, Wentao,Lian, Qi,Wang, Songping,Wei, Wentao,Zhou, Jingwei
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supporting information
p. 3261 - 3267
(2021/05/21)
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- Method for exciting C-C bond fracture acylation and application
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The invention provides a method for exciting C-C bond breakage acylation and application; the method comprises the following steps: mixing a compound with a structural formula shown in the specification with an organic solvent, and reacting in oxygen and
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Paragraph 0034-0042; 0205-0213
(2021/07/21)
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- Study on the mild, rapid and selective difluorocarbene-mediated triclassification of iododifluoroacetophenone with secondary amines and tree model for product classification
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Difluorocarbene is a very active and widely used intermediate in organic synthesis. In this work, a room temperature difluorocarbene-mediated triclassification reaction of iododifluoroacetophenone (2) and secondary amines with mild condition, short reaction time (only 10 min) and high selectivity had been studied, which produced one of the following three substances: N-CF2H derivatives (up to 87% yield), formamides (82–89% yield) or the recycled starting secondary amines. This phenomenon was related to the structural stability of the corresponding products. If unstable, it would be hydrolyzed to formamides first, and then further hydrolyzed to starting amines. Based on the geometric structure of the raw materials, the corresponding prediction tree model was established, which provided guidance for the further application of difluoromethylation of Vemurafenib (1ee) and AZD9291 (1ff).
- Chen, Xiu-Ping,Han, Jie,Hu, Yin-Jie,Li, Yun-Fang,Wang, Xiang-Cong,Ran, Jian-Xiong,Wang, Zhong-Hua,Wu, Fan-Hong
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- A substituent- And temperature-controllable NHC-derived zwitterionic catalyst enables CO2upgrading for high-efficiency construction of formamides and benzimidazoles
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Chemocatalytic upgrading of the greenhouse gas CO2 to valuable chemicals and biofuels has attracted broad attention in recent years. Among the reported approaches, N-formylation of CO2 with an amine is of great significance due to its versatility in the construction of N-containing linear and cyclic skeletons. Herein, a stable N-heterocyclic carbene-carboxyl adduct (NHC-CO2) was facilely prepared and could be used as a recyclable zwitterionic catalyst for efficient CO2 reductive upgrading via either N-formylation or further coupling with cyclization under mild conditions (25 °C, 1 atm CO2) using hydrosilane as a hydrogen source. More than 30 different alkyl and aromatic amines could be transformed into the corresponding formamides or benzimidazoles with remarkable yields (74%-98%). The electronic effect of the introduced substituent on NHC-CO2 was found to evidently affect the thermostability and nucleophilicity of the zwitterionic catalyst, which is directly correlated with its catalytic activity. Moreover, NHC-CO2 could supply CO2 by in situ decarboxylation at a specific temperature that is dependent on the introduced substituent type. Experimental and computational studies showed that the carboxyl species on NHC-CO2 was not only a nucleophilic center, but also a C1 source which rapidly captures or substitutes ambient CO2 during hydrosilylation. In addition, a simple and green conceptual process was designed for the product purification and catalyst recycling, with a good feasibility for small-scale production.
- Li, Hu,Li, Zhengyi,Wu, Hongguo,Yang, Song,Yu, Zhaozhuo,Zhang, Lilong,Zhu, Kaixun
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supporting information
p. 5759 - 5765
(2021/08/23)
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- Olefin functionalized IPr.HCl monomer as well as preparation method and application thereof
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The invention relates to an olefin functionalized IPr.HCl monomer, a preparation method thereof, a method for preparing an N-heterocyclic carbene functionalized organic polymer (PS-IPr-x) by using the olefin functionalized IPr.HCl monomer, and application of the N-heterocyclic carbene functionalized organic polymer as a heterogeneous catalyst for catalyzing reduction N-formylation of carbon dioxide and amine. A heterogeneous catalyst is prepared by using cheap and easily available DVB as a polymerization cross-linking agent through an AIBN-initiated olefin polymerization method, and has the advantages of low preparation cost and simple preparation method. Meanwhile, the catalytic activity of the catalyst is obviously higher than that of reported catalysts, and the catalyst has a wide practical application prospect.
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Paragraph 0069-0073; 0075; 0078
(2021/06/21)
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- Design of Lewis base functionalized ionic liquids for the N-formylation of amines with CO2 and hydrosilane: The cation effects
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A series of functionalized ionic liquids (ILs) were developed for the reductive functionalization of CO2 with amine and hydrosilane to afford formamides under mild conditions. It was found that 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)-based IL i.e. [DBUC12]Br showed high efficiency for the N-formylation reaction of amines without using any organic solvents or additives. Furthermore, control experiments suggested the cations with active hydrogen may weaken the nucleophilicity of anions through ion pairing interactions, thereby affecting the activation of hydrosilane. The reaction mechanism was then investigated by Density Functional Theory (DFT) calculations. This protocol represents a highly efficient and environmentally friendly example for catalytic conversion of CO2 into value-added chemicals such as formamide derivatives by employing DBU functionalized ILs.
- Li, Xiao-Ya,Fu, Hong-Chen,Liu, Xiao-Fang,Yang, Shu-Han,Chen, Kai-Hong,He, Liang-Nian
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p. 563 - 569
(2020/02/05)
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- Ligand-Enabled Ni-Al Bimetallic Catalysis for Nonchelated Dual C-H Annulation of Arylformamides and Alkynes
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A bifunctional secondary phosphine oxide (SPO) ligand-controlled method was developed for Ni-Al-catalyzed nonchelated dual C-H annulation of arylformamides with alkynes, providing a series of substituted amide-containing heterocycles in ≤97% yield. The SPO-bound bimetallic catalysis proved to be critical to the reaction efficiency.
- Luan, Yu-Xin,Wang, Yin-Xia,Ye, Mengchun,Zhang, Feng-Ping
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supporting information
(2020/03/19)
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- Synthesis of silyl formates, formamides, and aldehydesviasolvent-free organocatalytic hydrosilylation of CO2
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Carbon dioxide (CO2) was used as a C1 source to prepare silyl formates, formamides, and aldehydes. Tetrabutylammonium acetate (TBAA) catalyzed the solvent-freeN-formylation of amines with CO2and hydrosilane to give formamides including Weinreb formamide, Me(MeO)NCHO, which was successively converted into aldehydes by one-pot reactions with Grignard reagents.
- Ema, Tadashi,Hasegawa, Jun-Ya,Hiyoshi, Mahoko,Murata, Takumi,Ratanasak, Manussada
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supporting information
p. 5783 - 5786
(2020/06/03)
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- Selective: N-formylation/N-methylation of amines and N-formylation of amides and carbamates with carbon dioxide and hydrosilanes: Promotion of the basic counter anions of the zinc catalyst
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A catalyst composed of commercially available Zn(OAc)2 and 1,10-phenanthroline (phen) was effective in the N-formylation/N-methylation of amines using CO2 as the C1 source in the presence of hydrosilanes. An equimolar reaction of N-methylaniline with PhSiH3 under a CO2 atmosphere yielded the N-formylation product in 92% yield at 25 °C. Scale-up of the reaction using 10 mmol substrate was also successful in affording the desired product in 83% yield (1.1 g). This catalyst exhibits a high thermal stability and a turnover number (TON) of 385000 at 150 °C. In addition, the reaction of N-methylaniline in the presence of excess Ph2SiH2 produced N,N-dimethylaniline. Furthermore, our catalytic protocol was developed for the N-formylation of amides and carbamates, which have smaller pKa values and lower reactivities than the corresponding amines. The present Zn(OAc)2/phen catalyst was found to show versatility in the conversion of CO2 and amines into several functionalized organic chemicals under mild conditions. We propose that the basic counter anion (i.e., the acetate) of the catalyst activates both the Si-H and N-H bonds.
- Zhang, Qiao,Lin, Xiao-Tao,Fukaya, Norihisa,Fujitani, Tadahiro,Sato, Kazuhiko,Choi, Jun-Chul
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supporting information
p. 8414 - 8422
(2020/12/29)
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- Tetracoordinate borates as catalysts for reductive formylation of amines with carbon dioxide
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We report sodium trihydroxyaryl borates as the first robust tetracoordinate organoboron catalysts for reductive functionalization of CO2. These catalysts, easily synthesized from condensing boronic acids with metal hydroxides, activate main group element-hydrogen (E-H) bonds efficiently. In contrast to BX3 type boranes, boronic acids and metal-BAr4 salts, under transition metal-free conditions, sodium trihydroxyaryl borates exhibit high reactivity of reductive N-formylation toward a variety of amines (106 examples), including those with functional groups such as ester, olefin, hydroxyl, cyano, nitro, halogen, MeS-, ether groups, etc. The over-performance to catalyze formylation of challenging pyridyl amines affords a promising alternative method to the use of traditional formylation reagents. Mechanistic investigation supports electrostatic interactions as the key for Si/B-H activation, enabling alkali metal borates as versatile catalysts for hydroborylation, hydrosilylation, and reductive formylation/methylation of CO2.
- Du, Chen-Xia,Huang, Zijun,Jiang, Xiaolin,Li, Yuehui,Makha, Mohamed,Wang, Fang,Zhao, Dongmei
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supporting information
p. 5317 - 5324
(2020/09/17)
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- Engineering Porphyrin Metal-Organic Framework Composites as Multifunctional Platforms for CO2Adsorption and Activation
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As an effective solution toward the establishment of a sustainable society, the reductive transformation of CO2 into value-added products is certainly important and imperative. Herein, we report a porphyrin metal-organic framework composite Au@Ir-PCN-222, which is obtained through the in situ formation of Au nanoparticles in the coordination interspaces of Ir-PCN-222. Catalytic results show that Au@Ir-PCN-222 is highly efficient for CO2 reduction and aminolysis, giving rise to formamides in high yields and selectivities under room temperature and atmospheric pressure. Mechanistic studies disclose that the high efficiency of Au@Ir-PCN-222 is due to the synergistic catalysis of Au NPs and Ir-PCN-222, in which Au NPs can adsorb CO2 molecules on their surfaces and then increase the CO2 concentration in the cavities of the framework, and at the same time, Au NPs transfer electrons to Ir-porphyrin units and therefore increase the interactions with CO2 molecules.
- Liu, Jiewei,Fan, Yan-Zhong,Zhang, Kun,Zhang, Li,Su, Cheng-Yong
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p. 14548 - 14556
(2020/10/13)
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- Catalyst-free selective: N -formylation and N -methylation of amines using CO2 as a sustainable C1 source
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We herein describe catalyst-free selective N-formylation and N-methylation of amines using CO2 as a sustainable C1 source. By tuning the reaction solvent and temperature, the selective synthesis of formamides and methylamines is achieved in good to excellent yields using sodium borohydride (NaBH4) as a sustainable reductant.
- Zou, Qizhuang,Long, Guangcai,Zhao, Tianxiang,Hu, Xingbang
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supporting information
p. 1134 - 1138
(2020/03/11)
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- Iron-Catalyzed Selective N-Methylation and N-Formylation of Amines with CO2
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We herein describe an efficient iron-catalyzed selective N-methylation and N-formylation of amines with CO2 and silane using mono-phosphine as ligand. With commercially available [CpFe(CO)2]2 as catalyst, Fe-catalyzed methylation of amines was achieved with triphenylphosphine as a ligand. Using tributylphosphine as a ligand, Fe-catalyzed formylation of amines was realized at a lower temperature. The method was successfully applied in the late-stage methylation and formylation of drug molecules containing amine moiety. (Figure presented.).
- Li, Wen-Duo,Zhu, Dao-Yong,Li, Gang,Chen, Jie,Xia, Ji-Bao
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supporting information
p. 5098 - 5104
(2019/11/03)
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- Biomass-derived N-doped porous carbon: An efficient metal-free catalyst for methylation of amines with CO2
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Developing green, efficient, and low-cost catalysts for methylation of N-H by using CO2 as the C1 resource is highly desired yet remains a significant challenge. Herein, N-doped porous carbons (NPCs) were designed, synthesized, and proved to be an excellent metal-free catalyst for CO2-participated methylation conversion. NPCs were prepared via the pyrolysis of a mixture of tannic acid and urea. Both theoretical calculation and experiment demonstrate that the N species especially pyridinic N and pyrrolic N within NPCs can work as Lewis basic sites for attacking CO2 to weaken the CO bonds and lower the molecule conversion barrier, facilitating the subsequent methylation of N-H to produce, for example, N,N-dimethylaniline. Besides, the unique porous structure can enrich CO2 and accelerate mass transfer, synergistically promoting the conversion of CO2. The optimized NPC(1/5) catalyst, integrating the porous structure and strong Lewis basicity, exhibits excellent catalytic activity for CO2-based methylation reaction under mild conditions (1 bar CO2, 75 °C). Our work, for the first time, demonstrates the feasibility of using NPCs to catalyze the methylation of amino compounds to produce N,N-dimethylamine by exploiting CO2 as the C1 resource.
- Tang, Feiying,Wang, Liqiang,Liu, You-Nian
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supporting information
p. 6252 - 6257
(2019/12/03)
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- Catalyst-Free Transamidation of Aromatic Amines with Formamide Derivatives and Tertiary Amides with Aliphatic Amines
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A simple catalyst- and promoter-free protocol has been developed for the transamidation of weakly nucleophilic aromatic amines with formamide derivatives and low-reactivity tertiary amides with aliphatic amines. This strategy is advantageous because no catalyst or promoters are needed, no additives are required, separation and purification is easy, and the reaction is scalable. Significantly, this strategy was further applied to synthesize several pharmaceutical molecules on a gram scale, and excellent yields were achieved.
- Yin, Jiawen,Zhang, Jingyu,Cai, Changqun,Deng, Guo-Jun,Gong, Hang
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supporting information
p. 387 - 392
(2019/01/11)
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- The synthesis of cyanoformamides via a CsF-promoted decyanation/oxidation cascade of 2-dialkylamino-malononitriles
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A mild and efficient method for the synthesis of cyanoformamides from N,N-disubstituted aminomalononitriles with CsF as the promoter has been developed. This method features a wide substrate scope and high reaction efficiency, and will facilitate corresponding cyanoformamide-based biological studies and synthetic methodology development.
- Lei, Lin-Sheng,Xue, Cao-Gen,Xu, Xue-Tao,Jin, Da-Ping,Wang, Shao-Hua,Bao, Wen,Liang, Huan,Zhang, Kun,Asiri, Abdullah M.
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supporting information
p. 3723 - 3726
(2019/04/17)
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- An efficient method for the N-formylation of amines under catalyst- and additive-free conditions
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A simple catalyst- and additive-free method for the N-formylation of amines has been developed. The advantages of this protocol include a wide range of functional group tolerance, high efficiency and a lack of required extra promoters under mild conditions. This convenient strategy will provide a facile synthesis towards N-formamide natural products and pharmaceutical derivatives. A mechanism that involves difluorocarbene is proposed for this reaction.
- Xu, Zhuo-Wei,Xu, Wen-Yi,Pei, Xiao-Jun,Tang, Fei,Feng, Yi-Si
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supporting information
p. 1254 - 1258
(2019/04/10)
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- Imidazolium-Salt-Functionalized Covalent Organic Frameworks for Highly Efficient Catalysis of CO2 Conversion
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The conversion of CO2 into valuable chemicals is an ideal pathway for CO2 utilization in industry, although the development of highly efficient catalysts remains a challenge. Herein, the design and synthesis of two covalent organic frameworks (COFs) functionalized with imidazolium salts were reported as catalysts for CO2 conversion. The resultant COFs possessed highly crystalline structures, showed high stability and surface area, and contained dense catalytic active sites on the pore walls. They exhibited outstanding catalytic performances for the reaction of CO2 with epoxides without any solvent or cocatalyst under mild conditions and afforded a record turnover number of 495 000. In addition, the COFs could serve as effective catalysts in the reductive reaction of CO2 with amines. The results presented here thus demonstrate the exceptional potential of the functionalized COFs for various challenging CO2 transformations.
- Qiu, Jikuan,Zhao, Yuling,Li, Zhiyong,Wang, Huiyong,Shi, Yunlei,Wang, Jianji
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p. 2421 - 2427
(2019/05/15)
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- Mn-Catalyzed Selective Double and Mono-N-Formylation and N-Methylation of Amines by using CO2
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Functionalization of amines by using CO2 is of fundamental importance considering the abundance of amines and CO2. In this context, the catalytic formylation and methylation of amines represent convenient and successful protocols for selective CO2 utilization as a C1 building block. This study represents the first example of selective catalytic double N-formylation of aryl amines by using a dinuclear Mn complex in the presence of phenylsilane. This robust system also allows for selective formylation and methylation of amines under a range of conditions.
- Huang, Zijun,Jiang, Xiaolin,Zhou, Shaofang,Yang, Peiju,Du, Chen-Xia,Li, Yuehui
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p. 3054 - 3059
(2019/04/10)
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- Eco-friendly acetylcholine-carboxylate bio-ionic liquids for controllable: N-methylation and N-formylation using ambient CO2 at low temperatures
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Catalytic fixation of CO2 to produce valuable fine chemicals is of great significance to develop a green and sustainable circulation of excessive carbon in the environment. Herein, a series of non-toxic, biodegradable and recyclable acetylcholine-carboxylate bio-ionic liquids with different cations and anions were simply synthesized for producing formamides and methylamines using atmospheric CO2 as a carbon source, and phenylsilane as a hydrogen donor. The selectivity toward products was tuned by altering the reaction temperature under solvent or solvent-free conditions. N-Methylamines (ca. 96% yield) were obtained in acetonitrile at 50 °C, while N-formamides (ca. 99% yield) were attained without a solvent at 30 °C. The established bio-ionic liquid catalytic system found a wide range of applicability in substrates and possessed a high potentiality in scale-up to gram-grade production. The developed catalytic system was fairly stable, which could be easily reused without an apparent loss of reactivity, possibly due to the strong electrostatic interactions between the cation and anion. The combination of experimental and computational results explicitly elucidated the reaction mechanism: PhSiH3 activated by a bio-IL was favorable for the formation of silyl formate from hydrosilylation of CO2, followed by a reaction with an amine to give an N-formamide, while an N-methylamine was formed by further hydrosilylation of the N-formamide.
- Zhao, Wenfeng,Chi, Xiaoping,Li, Hu,He, Jian,Long, Jingxuan,Xu, Yufei,Yang, Song
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supporting information
p. 567 - 577
(2019/02/14)
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- Method for preparing N-formylated amine compounds
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The invention discloses a method for preparation N-formylated amine compounds. In the method, the amine compounds and 1,3-dihydroxy acetone are taken as reaction raw materials reacting in a reactor for 2-48 hours at the reaction temperature of 0-100DEG C in a reaction medium in the presence of composite catalysts and oxidants, and the N-formylated amine compounds are obtained. The method is simpleand moderate in reaction conditions, cost can be reduced, target products can be obtained with high yield, and the catalysts used have high catalytic activity and are easy to be separated from a reaction system and reuses; the method is environment friendly during the whole process, the reaction raw materials are easy to be converted from biodiesel by-product propylene glycol, and use of glycerolis facilitated.
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Paragraph 0040; 0048; 0049
(2018/11/03)
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- N-aryl formamide prepared by using ethyl bromodifluoroacetate as formylating reagent
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The invention discloses a compound of N-aryl formamide prepared by using ethyl bromodifluoroacetate as a formylating reagent. The compound is prepared by using N-alkyl arylamine as a raw material, ethyl bromodifluoroacetate as a formylating reagent and copper as a catalyst, adding different ligands, bases, etc., performing reaction under stirring in a reaction solvent at 100-120 DEG C for 10-14 hours; then filtering the reaction solution to obtain filtrate after reaction ending; concentrating the filtrate, removing the solvent by using a rotary evaporator to obtain a residue, treating the residue by silica gel column chromatography, eluting with an eluent, collecting the effluent according to the actual gradient; combining the effluent containing the product, concentrating the combined effluent to remove the solvent, and performing vacuum drying to obtain the target product. The compound has the advantages of simple and easily obtained raw materials, simple preparation process, less pollution, low energy consumption and high yield.
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Paragraph 0035
(2018/12/02)
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- Copper-Catalyzed N-Formylation of Amines through Tandem Amination/Hydrolysis/Decarboxylation Reaction of Ethyl Bromodifluoroacetate
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Ethyl bromodifluoroacetate (BrCF2COOEt) was first used as the N-formylating reagent in the copper-catalyzed N-formylation of amines. A range of primary, secondary, cyclic arylamines, and aliphatic amines underwent the N-formylation smoothly to furnish the N-formamides in moderate-to-excellent yields.
- Li, Xiao-Fang,Zhang, Xing-Guo,Chen, Fan,Zhang, Xiao-Hong
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p. 12815 - 12821
(2018/10/20)
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- Function-oriented ionic polymers having high-density active sites for sustainable carbon dioxide conversion
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On the basis of the development of function-oriented synthesis (FOS), we presented for the first time an efficient and one-pot construction of functional ionic polymers (FIPs) through the phenol-formaldehyde condensation process (pre-synthetic approach); FIPs had high density of Br?nsted acidic and ionic sites. Considering the electrophilic-nucleophilic dual activation of phenolic hydroxyl groups and bromide anions, the imidazolium-based FIP-Im exhibited high activity for metal-, solvent- and additive-free synthesis of cyclic carbonates from CO2 and epoxides under mild conditions. Then, to obtain higher ionic density and a more flexible skeleton, FIP-Im@QA was also prepared by implanting quaternary ammonium (QA) in the framework of FIP-IMvia the Williamson ether synthesis (post-synthetic modification), which demonstrated high efficiency in the N-formylation reaction of multitudinous secondary amines with CO2 and PhSiH3 at ambient temperature. More interestingly, these function-oriented catalysts were compatible with the target transformation under low CO2 concentration (15% in 85% N2, v/v) and were also reused for more than six times without a significant loss of activity and selectivity. Therefore, this study could not only facilitate the design and construction of FIPs, but also provide sustainable protocols for efficient production of value-added chemicals from CO2 under mild conditions.
- Chen, Yaju,Luo, Rongchang,Bao, Junhui,Xu, Qihang,Jiang, Jun,Zhou, Xiantai,Ji, Hongbing
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supporting information
p. 9172 - 9182
(2018/05/28)
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- Ru@PsIL-Catalyzed Synthesis of N-Formamides and Benzimidazole by using Carbon Dioxide and Dimethylamine Borane
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This work reports the synthesis and characterization of ruthenium nanoparticles (Ru NPs) supported on polymeric ionic liquids (PILs). This catalyst shows high catalytic activity towards the N-formylation of amines and synthesis of benzimidazoles from 1,2-diamines and carbon dioxide (CO2) by reductive dehydrogenation of dimethylamine borane. This methodology shows excellent functional group tolerance with broad substrate scope towards the synthesis of N-formamides and benzimidazoles. Interestingly, this protocol also provides the tandem reduction of 2-nitroamines and CO2 to synthesize benzimidazoles. It was proposed that the ionic liquid phase of the polymer plays pivotal roles such as assisting the stabilization of nanoparticles electrostatically, providing an ionic environment, and controlling the easy access of the substrates/reagents to the active sites. The developed methodology utilizes CO2 as a C1 source and water/ethanol as a green solvent system. Additionally, the catalyst was found to be recyclable in nature and shows five consecutive recycling runs without significant loss in its activity.
- Saptal, Vitthal B.,Sasaki, Takehiko,Bhanage, Bhalchandra M.
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p. 2593 - 2600
(2018/04/30)
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- Diverse catalytic reactivity of a dearomatized PN3P?-nickel hydride pincer complex towards CO2 reduction
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A dearomatized PN3P?-nickel hydride complex has been prepared using an oxidative addition process. The first nickel-catalyzed hydrosilylation of CO2 to methanol has been achieved, with unprecedented turnover numbers. Selective methylation and formylation of amines with CO2 were demonstrated by such a PN3P?-nickel hydride complex, highlighting its versatile functions in CO2 reduction.
- Li, Huaifeng,Gon?alves, Théo P.,Zhao, Qianyi,Gong, Dirong,Lai, Zhiping,Wang, Zhixiang,Zheng, Junrong,Huang, Kuo-Wei
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supporting information
p. 11395 - 11398
(2018/10/20)
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- DBU-Catalyzed Selective N-Methylation and N-Formylation of Amines with CO2 and Polymethylhydrosiloxane
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We describe herein an efficient organocatalytic system for the selective N-methylation and N-formylation of amines with carbon dioxide (CO2) as a sustainable C1 feedstock and polymethylhydrosiloxane (PMHS) as a cost-effectvie reducing reagent. High-yielding N-methylation products are obtained with low catalyst loading (1%) of DBU. Selective N-formylation of amines is achieved using the same catalytic system at a lower reaction temperature. (Figure presented.).
- Li, Gang,Chen, Jie,Zhu, Dao-Yong,Chen, Ye,Xia, Ji-Bao
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supporting information
p. 2364 - 2369
(2018/05/07)
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- Tungstate catalysis: Pressure-switched 2- and 6-electron reductive functionalization of CO2 with amines and phenylsilane
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An efficient and environmentally benign tungstate catalyst for reductive functionalization of CO2 with amines and phenylsilane was developed. By simply varying the pressure, 2-electron or 6-electron reduction of CO2 was successfully achieved with simultaneous C-N bond formation, thus leading to the formation of formamides and methylamines, respectively. That is, secondary and primary amines furnished the corresponding methylamines or dimethylamines in excellent yields under atmospheric pressure of CO2, while various formamides were formed in yields ranging from 52% to 98% when increasing the CO2 pressure to 2 MPa. 1H NMR studies and control experiments demonstrate that N-formylation proceeds through the formation of silyl formate, while N-methylation proceeds through an aminal intermediate generated by 4-electron reduction of CO2.
- Wang, Mei-Yan,Wang, Ning,Liu, Xiao-Fang,Qiao, Chang,He, Liang-Nian
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supporting information
p. 1564 - 1570
(2018/04/12)
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- B(C6F5)3: a robust catalyst for the activation of CO2 and dimethylamine borane for the N-formylation reactions
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In this work, B(C6F5)3 is utilized as an organocatalyst for the transition-metal-free N-formylation of amines using carbon dioxide (CO2) as a C1 source and dimethylamine borane (Me2NH·BH3) as a green hydrogen transfer source at 80 °C. Most reported works utilize silane and hydrogen for the N-formylation reactions using CO2 which have thus far been limited by low atom economy, high cost or the use of harsh reaction conditions. This catalytic protocol affords a broad range of formylated products in moderate to excellent yields under mild reaction conditions with a high TON and TOF. The bulky boron (B(C6F5)3) catalyst reacts with amines and forms a Frustrated Lewis Pair (FLP) and activates CO2 and Me2NH·BH3 molecules. Additionally, this boron catalyst shows high catalytic activity for the cyclization of o-phenylenediamines using CO2 and Me2NH·BH3 to synthesize benzimidazoles.
- Saptal, Vitthal B.,Juneja, Gaurav,Bhanage, Bhalchandra M.
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supporting information
p. 15847 - 15851
(2018/10/04)
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- Copper catalysis: Ligand-controlled selective: N -methylation or N -formylation of amines with CO2 and phenylsilane
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Cupric subcarbonate (Cu2(OH)2CO3) was found to be effective for the reductive functionalization of CO2 to produce formamides and methylamines with phenylsilane as reductant. Interestingly, N-formylation and N-methylation were switched on/off by subtly choosing the ligand: DPPB (1,4-bis(diphenylphosphino)butane) promoted N-methylation whereas Ph2CyP (diphenylcyclohexylphosphine) favored for N-formylation.
- Li, Xue-Dong,Xia, Shu-Mei,Chen, Kai-Hong,Liu, Xiao-Fang,Li, Hong-Ru,He, Liang-Nian
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supporting information
p. 4853 - 4858
(2018/11/21)
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- Method for preparing formamide and N-methylamines by carrying out selective reduction on carbon dioxide and amines regulated by ligand
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The invention relates to a method for preparing formamide and N-methylamines by carrying out selective reduction on carbon dioxide and amines regulated by a ligand. According to the method, copper salt is used as a catalyst, organic amine or organic phosphorus is used as the ligand, CO2 and a hydrosilane are respectively used as a C1 resource and a reducing agent, and amines are used as a nucleophilic reagent; a reaction is carried out in an organic solvent, the consumption of the catalyst is 1-5mol%, and the consumption of the ligand is 1-20 mol%, the reaction temperature is 20-80 DEG C, theCO2 pressure is 0.1-8.0 MPa, the reaction time is 10-48h, the highest yield of the formamide is up to 98%, and the highest yield of the N-methylamine is up to 95%. The method provided by the inventionhas the advantages that the ligand is used for a regulation method for selective reduction preparation of the formamide and the N-methylamines for the first time; the catalyst is low in price, easy to obtain and simple in composition; the renewable CO2 is used as a raw material, so that the use of the traditional toxic formylation and methylation reagents is avoided; the substrate is wide in application scope and is suitable for a variety of secondary amines.
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Paragraph 0127-0134
(2019/01/14)
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- Cooperative Catalytic Activation of Si?H Bonds: CO2-Based Synthesis of Formamides from Amines and Hydrosilanes under Mild Conditions
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A simple cooperative catalytic system was successfully developed for the solvent-free N-formylation of amines with CO2 and hydrosilanes under ambient conditions, which was composed of a Zn(salen) catalyst and quaternary ammonium salt. These commercially available binary components activated the Si?H bonds effectively, owing to the intermolecular synergistic effect between Lewis base and transition metal center (LB–TM), and subsequently facilitated the insertion of CO2 to form the active silyl formats, thereby leading to excellent catalytic performance at a low catalyst loading. Furthermore, the bifunctional Zn(salen) complexes, with two imidazolium-based ionic-liquid (IL) units at the 3,3′-position of salen ligand, acted as intramolecularly cooperative catalysts, and the solvent-regulated separation resulted in facile catalyst recycling and reuse.
- Luo, Rongchang,Lin, Xiaowei,Chen, Yaju,Zhang, Wuying,Zhou, Xiantai,Ji, Hongbing
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p. 1224 - 1232
(2017/03/29)
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- Catalyst-free: N -formylation of amines using BH3NH3 and CO2 under mild conditions
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The catalyst-free N-formylation of amines using CO2 as the C1 source and BH3NH3 as the reductant has been developed for the first time. The corresponding formylated products of both primary and secondary amines are obtained in good to excellent yields (up to 96% of isolated yield) under mild conditions.
- Zhao, Tian-Xiang,Zhai, Gao-Wen,Liang, Jian,Li, Ping,Hu, Xing-Bang,Wu, You-Ting
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supporting information
p. 8046 - 8049
(2017/07/22)
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- Metallosalen-Based Ionic Porous Polymers as Bifunctional Catalysts for the Conversion of CO2 into Valuable Chemicals
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A series of new metallosalen-based ionic porous organic polymers (POPs) were synthesized for the first time using a simple unique strategy based on the free-radical copolymerization reaction. Various techniques were used to characterize the physicochemical properties of these catalysts. These well-designed materials endowed high surface area, hierarchical porous structures, and enhanced CO2/N2 adsorptive selectivity. Moreover, these POPs having both metal centers (Lewis acid) and ionic units (nucleophile) could serve as bifunctional catalysts in the catalytic conversion of CO2 into high value-added chemicals without any additional co-catalyst under mild and solvent-free conditions, for example, CO2/epoxides cycloaddition and Nformylation of amines from CO2 and hydrosilanes. The results demonstrated that the irregular porous structure was very favorable for the diffusion of substrates and products, and the microporous structural property resulted in the enrichment of CO2 near the catalytic centers in the CO2-involved transformations. Additionally, the superhydrophobic property could not only enhance the chemoselectivity of products but also promote the stability and recyclability of catalysts.
- Luo, Rongchang,Chen, Yaju,He, Qian,Lin, Xiaowei,Xu, Qihang,He, Xiaohui,Zhang, Wuying,Zhou, Xiantai,Ji, Hongbing
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p. 1526 - 1533
(2017/04/14)
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- Electrostatic Catalyst Generated from Diazadiborinine for Carbonyl Reduction
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Since the seminal discovery by van der Waals in the late 19th century that weak attractive forces exist between even electrically neutral atoms or molecules, a number of noncovalent interactions have been recognized. Among them, electrostatic interactions such as hydrogen bonds play pivotal roles in countless chemical processes and biochemical living systems. By mimicking biocatalysis, various organocatalysts equipped with hydrogen-bond functionality have been developed; however, a challenge has persisted in designing catalysts exploiting other types of noncovalent interactions. Here, we report metal-free hydroboration reactions of carbonyl compounds and CO2 catalyzed by aromatic diazadiborinine. A joint experimental and computational study on the reaction mechanism suggests that adducts of diazadiborinine with carbonyl and CO2 formed at the initial stage of the reactions serve as actual catalysts. The former stabilizes the transition state by using the electrostatic interaction between the hydride of borane and the polar, hole-shaped structure of the adduct.
- Wu, Di,Wang, Ruixing,Li, Yongxin,Ganguly, Rakesh,Hirao, Hajime,Kinjo, Rei
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supporting information
p. 134 - 151
(2017/07/17)
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- Oxidative N-dealkylation of tertiary amines with tetraethylammonium periodate catalyzed by metal complexes
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The oxidative N-dealkylation of tertiary amines, N,N-dimethylaniline and N,N-diethylaniline, catalyzed by some sterically hindered FeIII complexes and tetraethylammonium periodate as oxidant gave the corresponding N-dealkylated and mono-oxygenated products in good yields. The presence of electronegative atoms on the catalyst complexes influenced the product yield. The presence of H-atom abstractor 2,6-di-tert-butyl-4-methylphenol did not influence product formation, thereby suggesting that the reaction proceeded predominantly via a one-electron transfer mechanism rather than via hydrogen abstraction. Tetraethylammonium periodate favoured oxygen transfer to the substrate.
- Bhat, Daisy,Sharma, Nidhi
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p. 233 - 236
(2017/03/13)
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- Visible-light-induced oxidative formylation of N-alkyl-N-(prop-2-yn-1-yl)anilines with molecular oxygen in the absence of an external photosensitizer
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Visible-light-induced oxidative formylation of N-alkyl-N-(prop-2-yn-1-yl)anilines with molecular oxygen in the absence of an external photosensitizer was developed and afforded the corresponding formamides in good yields under mild conditions. The investigation of the mechanism disclosed that both the starting material and the product act as photosensitizers, and 1O2 and O2- are generated through energy transfer and a single electron transfer pathway and play an important role in the reaction.
- Ji, Wangqin,Li, Pinhua,Yang, Shuai,Wang, Lei
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supporting information
p. 8482 - 8485
(2017/08/03)
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- Selective formylation and methylation of amines using carbon dioxide and hydrosilane catalyzed by alkali-Metal carbonates
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The formylation and methylation of amines with carbon dioxide and hydrosilanes are emerging yet important types of transformations for CO2. Catalytic methods effective for both reactions with wide substrate scopes are rare because of the difficulty in controlling the selectivity. Herein, we report that simple and readily available inorganic bases alkali-metal carbonates, especially cesium carbonatecatalyze both the formylation and methylation reactions efficiently under mild conditions. The selectivity can be conveniently controlled by varying the reaction temperature and silane. A “cesium effect” on both reactions was observed by comparing the catalytic activity of various alkali-metal carbonates. Combined experimental and computational studies suggested the following reaction mechanism: (i) activation of Si?H by Cs2CO3, (ii) insertion of CO2 into Si?H, (iii) formylation of amines by silyl formate, and (iv) reduction of formamides to methylamines.
- Fang, Chi,Lu, Chunlei,Liu, Muhua,Zhu, Yiling,Fu, Yao,Lin, Bo-Lin
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p. 7876 - 7881
(2018/05/23)
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- N-heterocyclic olefins as robust organocatalyst for the chemical conversion of carbon dioxide to value-added chemicals
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In this report, the activity of N-heterocyclic olefins (NHOs) as a newly emerging class of organocatalyst is investigated for the chemical fixation of carbon dioxide through reactions with aziridines to form oxazolidinones and the N-formylation of amines with polymethylhydrosiloxane (PMHS) or 9-borabicy-clo[3.3.1]nonane (9-BBN) as the reducing agent under mild conditions. The exocyclic carbon atoms of NHOs are highly nucleophilic owing to the electron-donating ability of the two nitrogen atoms. This high nucleophilicity of the NHOs activates CO2 molecules to form zwitterionic NHO–carboxylate (NHO– CO2) adducts, which are active in formylation reactions as well as the carboxylation of aziridines to oxazolidinones.
- Saptal, Vitthal B.,Bhanage, Bhalchandra M.
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p. 1980 - 1985
(2017/07/13)
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- Supported nano-gold-catalyzed N-formylation of amines with paraformaldehyde in water under ambient conditions
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A simple and efficient Au/Al2O3 catalyst was prepared by the co-precipitation method for the oxidative N-formylation of amines with paraformaldehyde. Under the optimized reaction conditions, excellent amine conversion and N-formamide selectivity can be obtained with up to 97% yield with water as the solvent under ambient conditions. This catalyst tolerated a wide range of primary amines and second amines, and it can be reused for at least five runs without obvious deactivation.
- Ke, Zhengang,Zhang, Yan,Cui, Xinjiang,Shi, Feng
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p. 808 - 816
(2016/02/12)
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- A Practical and General Base-Catalyzed Carbonylation of Amines for the Synthesis of N-Formamides
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A highly practical and general base-catalyzed carbonylation of amines to the corresponding N-formamides has been realized. Cheap inorganic bases, including GroupIA and IIA metal hydroxides, alkoxides, carbonates, and phosphates, were effective catalysts for the transformation. In the presence of 10-40mol% of KOH or K2CO3, various amines were converted into the corresponding N-formamides in good-to-excellent yields using CO as the formylation reagents. Metal-free carbonylation: A simple and practical procedure for the catalytic carbonylation of amines has been developed (see scheme). In the presence of 10-40mol% of KOH or K2CO3, various amines have been converted into the corresponding N-formamides in good-to-excellent yields by using CO as the formylation reagent.
- Li, Wanfang,Wu, Xiao-Feng
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supporting information
p. 14943 - 14948
(2015/10/19)
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- Mn-promoted aerobic oxidative C-C bond cleavage of aldehydes with dioxygen activation: A simple synthetic approach to formamides
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A novel Mn-promoted aerobic oxidative C-C bond cleavage of aldehydes with dioxygen activation has been developed. The usage of molecular oxygen (1 atm) as oxidant, reactant, and an initiator to trigger this transformation makes this transformation very green and practical. A plausible radical process is proposed on the basis of mechanistic studies. Furthermore, this method provides a practical, neutral, and mild synthetic approach to formamides, which are important units in biologically active molecules.
- Zhang, Chun,Xu, Zejun,Shen, Tao,Wu, Guolin,Zhang, Liangren,Jiao, Ning
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supporting information; experimental part
p. 2362 - 2365
(2012/06/29)
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- Oxoiminium Ions for N-Demethylation: 1-Oxo-2,2,6,6,-tetramethylpiperidinium Chloride
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In an attempt to assess the synthetic utylity of oxoiminium ions as oxidizing agents and to delineate their reaction mechanisms, we reacted 1-oxo-2,2,6,6-tetramethylpiperidinium chloride (1) with several N,N-dialkylanilines.With N,N-dimethylaniline the only basic product was N-nethylaniline while N- methylformanilide was the only neutral product.The relative amounts of base and neutral product proved to be sensitive to the amount of water present in the reaction medium.With N-alkyl-N-methylanilines, the basic products were N-alkylanilines from exlusive loss of the N-methyl group.The neutral products were the N-alkylformanilides.The alkyl groups studied were ethyl, n-butyl, isopropyl, and benzyl.With N-tert-butyl-N-methylaniline, there was no observed reaction, and N,N-diethylaniline was found to be significantly less reactive than N,N-dimethylaniline.This study has shown that 1 is selective in N-demethylation of anilines in the presence of other alkyl groups either on the same nitrogen or on separate nitrogens.These results have been interpreted in terms of important steric interactions resulting from formation of an adduct en route to an intermediate iminium ion.
- Hunter, Duncan H.,Racok, Julie S.,Rey, Allan W.,Ponce, Yolanda Zea
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p. 1278 - 1281
(2007/10/02)
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- CARBONYLATION OF AMINES CATALYZED BY ORGANOZINC COMPOUND
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Dietylzinc was found to catalyze the carbonylation of amines including aromatic amines to give the corresponding formamides in good yields.
- Yoshida, Yasuhiko,Asano, Shoichi,Inoue, Shohei
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p. 1073 - 1076
(2007/10/02)
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- Reaction of Ortho Esters with Secondary Amines
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The scope of the reaction of ortho esters with secondary amines has been explored.With p-toluenesulfonic acid as catalyst, N-alkylanilines and orthoformates gave high yields of N-alkylformanilides and N,N-dialkylanilines in contrast to previous work with other acid catalysts where ortho amides were produced in low yield.Aliphatic cyclic amines (e.g., morpholine, piperidine) and orthoformates gave the corresponding ortho amides.This constitutes a new convenient synthesis of these useful reagents.
- Swaringen, Roy A.,Eaddy, John F.,Henderson, Thomas R.
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p. 3986 - 3989
(2007/10/02)
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- EFFECT OF THE STRUCTURE OF N-SUBSTITUTED 1,3-OXAAZACYCLOPENTANES ON THEIR REACTIVITY IN FREE-RADICAL ISOMERIZATION
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During the thermal decomposition of tert-butyl peroxide (120 - 150 deg C) in a medium of N-substituted 1,3-oxaazacyclopentanes the latter change into the N,N-disubstituted amides of carboxylic acids by a mechanism of an unbranched chain reaction with quadratic termination at the rearranged radicals.The effect of the nature and the position of the substituents on the reactivity of 1,3-oxaazacyclopentanes in the free-radical isomerization reaction was investigated.The kinetic data and activation parameters characterizing the reactivity of 1,3-oxaazacyclopentanes were determined.
- Lapshova, A. A.,Zorin, V. V.,Zlotskii, S. S.,Karakhanov, R. A.,Rakhmankulov, D. L.
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p. 325 - 330
(2007/10/02)
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