- Reactivity of heterocyclic α-aminomethylsilanes with alcohols
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[Figure not available: see fulltext.] Alkoxylation of N-substituted heterocyclic aminomethylsilyl moieties was studied using primary and tertiary alcohols. The reaction of 4-(silylmethyl)morpholine and 1-(silylmethyl)azepane under catalyst- and solvent-free conditions leads to the formation of dialkoxy- and trialkoxyaminomethylsilyl derivatives. The methanolysis of 4-(silylmethyl)morpholine resulted in trimethoxyaminomethylsilane formation as the main product and two byproducts, i.e., tetramethoxysilane and N-methylmorpholine.
- Pypowski, Krzysztof,Mojzych, Mariusz
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p. 320 - 324
(2021/03/31)
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- Homoleptic Bis(trimethylsilyl)amides of Yttrium Complexes Catalyzed Hydroboration Reduction of Amides to Amines
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Homoleptic lanthanide complex Y[N(TMS)2]3 is an efficient homogeneous catalyst for the hydroboration reduction of secondary amides and tertiary amides to corresponding amines. A series of amides containing different functional groups such as cyano, nitro, and vinyl groups were found to be well-tolerated. This transformation has also been nicely applied to the synthesis of indoles and piribedil. Detailed isotopic labeling experiments, control experiments, and kinetic studies provided cumulative evidence to elucidate the reaction mechanism.
- Ye, Pengqing,Shao, Yinlin,Ye, Xuanzeng,Zhang, Fangjun,Li, Renhao,Sun, Jiani,Xu, Beihang,Chen, Jiuxi
-
supporting information
p. 1306 - 1310
(2020/02/22)
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- Reduction of Amides to Amines under Mild Conditions via Catalytic Hydrogenation of Amide Acetals and Imidates
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A simple and general protocol was developed for selective conversion of amides into amines. Amides were converted into amide acetals and imido esters by O-alkylation and then hydrogenated without isolation into amines under very mild reaction conditions over standard hydrogenation catalysts. Triethyloxonium tertafluoroborate, methyl trifluoromethanesulfonate, dimethyl sulfate and ethyl chloroformate were validated as alkylating agent. The synthetic utility of this approach was demonstrated by the selective carbonyl reduction of peptide groups. Carbonyl reduction of peptide group proceeds chemoselective without racemization of the neighboring chiral center. (Figure presented.).
- Kadyrov, Renat
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p. 185 - 191
(2018/11/23)
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- A BEt3-Base catalyst for amide reduction with silane
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Reported herein is the development of a simple but practical catalytic system for the selective reduction of amides with hydrosilane or hydrosiloxane. Low-cost and readily available triethylborane (1.0 M in THF), in combination with a catalytic amount of an alkali metal base, was found to catalyze the reduction of all three amide classes (tertiary, secondary, and primary amides) to form amines under mild conditions. In addition, the selective transformation of secondary amides to aldimines and primary amides to nitriles can also be achieved by using a proper combination of BEt3 and base. The scope of these BEt3-base-catalyzed amide hydrosilylation reactions has been explored in depth. Preliminary results of mechanistic studies suggest a modified Piers' silane Si-H···B activation mode wherein the hydride abstraction by BEt3 is promoted by the coordination of an alkoxide or hydroxide anion to the Si center.
- Yao, Wubing,Fang, Huaquan,He, Qiaoxing,Peng, Dongjie,Liu, Guixia,Huang, Zheng
-
-
- A BEt3-Base Catalyst for Amide Reduction with Silane
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Reported herein is the development of a simple but practical catalytic system for the selective reduction of amides with hydrosilane or hydrosiloxane. Low-cost and readily available triethylborane (1.0 M in THF), in combination with a catalytic amount of an alkali metal base, was found to catalyze the reduction of all three amide classes (tertiary, secondary, and primary amides) to form amines under mild conditions. In addition, the selective transformation of secondary amides to aldimines and primary amides to nitriles can also be achieved by using a proper combination of BEt3 and base. The scope of these BEt3-base-catalyzed amide hydrosilylation reactions has been explored in depth. Preliminary results of mechanistic studies suggest a modified Piers' silane Si-H···B activation mode wherein the hydride abstraction by BEt3 is promoted by the coordination of an alkoxide or hydroxide anion to the Si center.
- Yao, Wubing,Fang, Huaquan,He, Qiaoxing,Peng, Dongjie,Liu, Guixia,Huang, Zheng
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p. 6084 - 6093
(2019/05/24)
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- Selective synthesis of formamides, 1,2-bis(N-heterocyclic)ethanes and methylamines from cyclic amines and CO2/H2 catalyzed by an ionic liquid-Pd/C system
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The reduction of CO2 with amines and H2 generally produces N-formylated or N-methylated compounds over different catalysts. Herein, we report the selective synthesis of formamides, 1,2-bis(N-heterocyclic)ethanes, and methylamines, which is achieved over an ionic liquid (IL, e.g., 1-butyl-3-methylimidazolium tetrafluoroborate, [BMIm][BF4])-Pd/C catalytic system. By simply varying the reaction temperature, formamides and methylamines can be selectively produced, respectively, in high yields. Interestingly, 1,2-bis(N-heterocyclic)ethanes can also be obtained via the McMurry reaction of the formed formamide coupled with subsequent hydrogenation. It was found that [BMIm][BF4] can react with formamide to form a [BMIm]+-formamide adduct; thus combined with Pd/C it can catalyze McMurry coupling of formamide in the presence of H2 to afford 1,2-bis(N-heterocyclic)ethane. Moreover, Pd/C-[BMIm][BF4] can further catalyze the hydrogenolysis of 1,2-bis(N-heterocyclic)ethane to access methylamine. [BMIm][BF4]-Pd/C was tolerant to a wide substrate scope, giving the corresponding formamides, 1,2-bis(N-heterocyclic)ethanes or methylamines in moderate to high yields. This work develops a new route to produce N-methylamine and opens the way to produce 1,2-bis(N-heterocyclic)ethane from cyclic amine as well.
- Li, Ruipeng,Zhao, Yanfei,Wang, Huan,Xiang, Junfeng,Wu, Yunyan,Yu, Bo,Han, Buxing,Liu, Zhimin
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p. 9822 - 9828
(2019/11/11)
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- Remarkably high catalyst efficiency of a disilaruthenacyclic complex for hydrosilane reduction of carbonyl compounds
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A disilaruthenacyclic complex (1) showed extremely high catalytic activity for hydrosilane reduction of aldehydes and ketones to silyl ethers and secondary and tertiary amides to the corresponding amines. An σ-CAM mechanism was proposed to explain the activity.
- Tahara, Atsushi,Sunada, Yusuke,Takeshita, Takashi,Inoue, Ryoko,Nagashima, Hideo
-
supporting information
p. 11192 - 11195
(2018/10/24)
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- Borinic Acid Catalysed Reduction of Tertiary Amides with Hydrosilanes: A Mild and Chemoselective Synthesis of Amines
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A reduction of various aryl, alkyl, and α,β-unsaturated amides with phenylsilane, catalysed by a borinic acid, is reported. The unprecedented reaction was carried out under very mild conditions and led to useful amines. Furthermore, the reaction tolerates a variety of functional groups. Initial investigations implicated that an intermediate diarylhydroborane is involved in the reaction mechanism.
- Chardon, Aurélien,Mohy El Dine, Tharwat,Legay, Rémi,De Paolis, Micha?l,Rouden, Jacques,Blanchet, Jér?me
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supporting information
p. 2005 - 2009
(2017/02/19)
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- Rhenium-Loaded TiO2: A Highly Versatile and Chemoselective Catalyst for the Hydrogenation of Carboxylic Acid Derivatives and the N-Methylation of Amines Using H2 and CO2
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Herein, we report a heterogeneous TiO2-supported Re catalyst (Re/TiO2) that promotes various selective hydrogenation reactions, which includes the hydrogenation of esters to alcohols, the hydrogenation of amides to amines, and the N-methylation of amines, by using H2 and CO2. Initially, Re/TiO2 was evaluated in the context of the selective hydrogenation of 3-phenylpropionic acid methyl ester to afford 3-phenylpropanol (pH2 =5 MPa, =5 MPa, T=180 °C), which revealed a superior performance over other catalysts that we tested in this study. In contrast to other typical heterogeneous catalysts, hydrogenation reactions with Re/TiO2 did not produce dearomatized byproducts. DFT studies suggested that the high selectivity for the formation of alcohols in favor of the hydrogenation of aromatic rings is ascribed to the higher affinity of Re towards the COOCH3 group than to the benzene ring. Moreover, Re/TiO2 showed a wide substrate scope for the hydrogenation reaction (19 examples). Subsequently, this Re/TiO2 catalyst was applied to the hydrogenation of amides, the N-methylation of amines, and the N-alkylation of amines with carboxylic acids or esters.
- Toyao, Takashi,Siddiki,Morita, Yoshitsugu,Kamachi, Takashi,Touchy, Abeda S.,Onodera, Wataru,Kon, Kenichi,Furukawa, Shinya,Ariga, Hiroko,Asakura, Kiyotaka,Yoshizawa, Kazunari,Shimizu, Ken-Ichi
-
supporting information
p. 14848 - 14859
(2017/10/27)
-
- A new route to N-aromatic heterocycles from the hydrogenation of diesters in the presence of anilines
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The hydrogenation of dicarboxylic acids and their esters in the presence of anilines provides a new synthesis of heterocycles. [Ru(acac)3] and 1,1,1-tris(diphenylphosphinomethyl)ethane (triphos) gave good to excellent yields of the cyclic amines at 220 °C. When aqueous ammonia was used with dimethyl 1,6-hexadienoic acid, ?-caprolactam was obtained in good yield. A side reaction involving alkylation of the amine by methanol was suppressed by using diesters derived from longer chain and branched alcohols. Hydrogenation of optically pure diesters (dimethyl (R)-2-methylbutanedioate and dimethyl (S)-2-methylbutanedioate) with aniline afforded racemic 3-methyl-1-phenylpyrrolidine in 78% yield.
- Shi, Yiping,Kamer, Paul C. J.,Cole-Hamilton, David J.,Harvie, Michelle,Baxter, Emma F.,Lim, Kate J. C.,Pogorzelec, Peter
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p. 6911 - 6917
(2017/10/05)
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- Continuous N-alkylation reactions of amino alcohols using γ-Al2O3 and supercritical CO2: Unexpected formation of cyclic ureas and urethanes by reaction with CO2
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The use of γ-Al2O3 as a heterogeneous catalyst in scCO2 has been successfully applied to the amination of alcohols for the synthesis of N-alkylated heterocycles. The optimal reaction conditions (temperature and substrate flow rate) were determined using an automated self-optimising reactor, resulting in moderate to high yields of the target products. Carrying out the reaction in scCO2 was shown to be beneficial, as higher yields were obtained in the presence of CO2 than in its absence. A surprising discovery is that, in addition to cyclic amines, cyclic ureas and urethanes could be synthesised by incorporation of CO2 from the supercritical solvent into the product.
- Streng, Emilia S.,Lee, Darren S.,George, Michael W.,Poliakoff, Martyn
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p. 329 - 337
(2017/03/15)
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- Catalytic Hydrogenation for Producing Amines from Carboxylic Acid Amides, Carboxylic Acid Diamides, Di-, Tri-, or Polypeptides, or Peptide Amides
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The present invention relates to a process for the preparation of amines, comprising the following steps: a. reaction of a (i) carboxylic acid amide of the general formula (I), or (ii) carboxylic acid diamide of the general formula (II), or (iii) di-, tri- or polypeptide, or (iv) peptide amide with carboxy-terminal amide function with an alkylating agent, b. addition of a hydrogenation catalyst to the reaction mixture in a molar ratio of from 1:10 to 1:100 000, based on carboxylic acid amide, carboxylic acid diamide, di-, tri- or polypeptide or peptide amide, c. reaction of the reaction mixture with hydrogen, where a hydrogen pressure of from 0.1 bar to 200 bar is established and where a temperature in a range of from 0° C. to 250° C. is established.
- -
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Page/Page column 183-184
(2016/10/11)
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- Transition metal-free methylation of amines with formaldehyde as the reductant and methyl source
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A simple transition metal-free procedure using formaldehyde for the N,N-dimethylation and N-methylation of primary and secondary anilines is reported. The reaction showed limitations on sterically hindered and electron-withdrawing anilines, but is successful on amines with electron-donating substituents. Formaldehyde acts as both the reducing agent and the carbon source in the reaction.
- Man, Nikki Y.T.,Li, Wanfang,Stewart, Scott G.,Wu, Xiao-Feng
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p. 345 - 347
(2015/11/25)
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- Sustainable heterogeneous platinum catalyst for direct methylation of secondary amines by carbon dioxide and hydrogen
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Pt and MoOx co-loaded TiO2 is found to be highly effective for direct methylation of aliphatic and aromatic secondary amines by CO2 and H2 under solvent-free conditions. This is the first additive-free and reusable heterogeneous catalytic system with acceptable turnover number. Over and over: A heterogeneous Pt catalyst for direct methylation of aromatic amines by CO2 and H2 with high reusability and an order of magnitude higher turnover number than previous catalysts has been demonstrated (see scheme).
- Kon, Kenichi,Siddiki, S. M. A. Hakim,Onodera, Wataru,Shimizu, Ken-Ichi
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p. 6264 - 6267
(2014/06/09)
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- A practical procedure for reduction of primary, secondary and tertiary amides to amines
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A mild and general procedure for reduction of primary, secondary, and tertiary amides using catalytic triruthenium dodecacarbonyl and 1,1,3,3-tetramethyldisiloxane as reductant is described. The reaction is tolerant of numerous functional groups, and the amine products can often be isolated by direct crystallization as hydrochloride salts. The catalyst and silane are commercially available, air stable, and inexpensive, making the procedure accessible for both laboratory and large-scale applications. Copyright
- Reeves, Jonathan T.,Tan, Zhulin,Marsini, Maurice A.,Han, Zhengxu S.,Xu, Yibo,Reeves, Diana C.,Lee, Heewon,Lu, Bruce Z.,Senanayake, Chris H.
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supporting information
p. 47 - 52
(2013/03/13)
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- Cesium carbonate-catalyzed reduction of amides with hydrosilanes
-
Cesium carbonate has been found to be an effective catalyst for the reduction of tertiary carboxamides with the simple, commercially available PhSiH3 under solvent-free conditions. The catalytic system can effectively reduce a range of amides under relatively mild conditions (from room temperature to 80 C) to yield the corresponding amines in good to excellent yields (71-100%) and thus has the potential for practical applications.
- Xie, Weilong,Zhao, Mengdi,Cui, Chunming
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p. 7440 - 7444
(2014/04/03)
-
- Selective reduction of amides to amines by boronic acid catalyzed hydrosilylation
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Not a 'B'ore! Benzothiophene-based boronic acids catalyze the reduction of tertiary, secondary, and primary amides in the presence of a hydrosilane. The reaction demonstrates good functional-group tolerance. Copyright
- Li, Yuehui,Molina De La Torre, Jesus A.,Grabow, Kathleen,Bentrup, Ursula,Junge, Kathrin,Zhou, Shaolin,Brueckner, Angelika,Beller, Matthias
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p. 11577 - 11580
(2013/11/06)
-
- Highly efficient gold nanoparticle catalyzed deoxygenation of amides, sulfoxides, and pyridine N-oxides
-
Selective deoxygenation is one of the most important reactions in the areas of total synthesis, biological chemistry, and transformation of renewable biomass resources.To date, many useful methods for the selective deoxygenation of oxygen-containing organic molecules, such as amides, nitro compounds, epoxides, sulfoxides, and those with Noxide groups, have been developed. However, these methods often include stoichiometric reactions. Some successful catalysts have been reported,but most of them are homogeneous systems and still suffer from low activities and selectivities, harsh reaction conditions, and tedious workup procedures. Therefore, further development of highly efficient heterogeneous catalysts for selective deoxygenations is highly desired.
- Mikami, Yusuke,Noujima, Akifumi,Mitsudome, Takato,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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experimental part
p. 1768 - 1772
(2011/03/21)
-
- Dialkylamino and nitrogen heterocyclic analogues of hexadecylphosphocholine and cetyltrimetylammonium bromide: Effect of phosphate group and environment of the ammonium cation on their biological activity
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A series of dialkylamino and nitrogen heterocyclic analogues of hexadecylphosphocholine and cetyltrimethylammonium bromide have been synthesized. The prepared compounds exhibit significant cytotoxic, antifungal and antiprotozoal activities. Alkylphosphocholines possess higher antifungal activity against Candida albicans in comparison with quaternary ammonium compounds. However, quaternary ammonium compounds exhibit significant higher activity against human tumor cells and Acanthamoeba lugdunensis compared to alkylphosphocholines. In addition, their haemolytic toxicity has been investigated. The relationship between structure and biological activity of the tested compounds is discussed.
- Lukac, Milos,Mojzis, Jan,Mojzisova, Gabriela,Mrva, Martin,Ondriska, Frantisek,Valentova, Jindra,Lacko, Ivan,Bukovsky, Marian,Devinsky, Ferdinand,Karlovska, Janka
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scheme or table
p. 4970 - 4977
(2010/02/27)
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- METHODS AND COMPOSITIONS FOR REPELLING ARTHROPODS
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A method for repelling arthropods involving treating an object or area with an arthropod repelling effective amount of at least one compound having the formula wherein X is O, S, NH, N-NH2, N-CH3 or CH2, R' is H or alkyl, R" is alkyl, n is 0, 1, 2, 3 or 4, and mixtures thereof, optionally including a earner material or earner. The compound is preferably selected from homopiperazine, 1-methylhomopiperazine, 1-methylpyrrolidine, (R)- (-)-2-methylpiperazine, (S)-(+)-2-methylpiperazine, 2-methylpiperazine, 1 -methylpiperazine, pyrrolidine, 1-methylpiperidine, piperidine, 1-ethylpiperazine, 1-methylimidazolidine, 1- methylthiomorpholine, 1,4-dimethylpiperazine, homopiperidine, imidazolidine, 4- methylpiperidine, thiomoφholine, l-amino-4-methylpiperazine, 4-methylmoipholine, azocane, 2,6-dimethylpiperazine, 2,5-dimethylpiperazine, piperazine, 1-methylhomopiperidine, or mixtures thereof.
- -
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Page/Page column 25
(2008/12/07)
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- PROCESS FOR THE PRODUCTION OF LACTAMS
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A homogeneous process for the hydrogenation of dicarboxylic acid and/or derivative thereof with an amine in the presence of a catalyst comprising: (a) ruthenium or osmium; and (b) an organic phosphine; and wherein the hydrogenation is carried out in the presence of water.
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Page/Page column 11
(2008/06/13)
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- Transition-metal complex-catalyzed reduction of amides with hydrosilanes: A facile transformation of amides to amines
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The reaction of amides with hydrosilanes is catalyzed by a variety of transition-metal complexes in the presence or absence of halides and amines as co-catalysts to afford the corresponding amines in good yields.
- Igarashi, Mamoru,Fuchikami, Takamasa
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p. 1945 - 1947
(2007/10/03)
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- N-alkylation of amines under microwave irradiation: Modified eschweiler-clarke reaction
-
The N-alkylation of hexahydroazepine and benzylamine is performed under microwave irradiation in the presence of formic acid and different aldehydes or ketones. Good yields were obtained with reactive carbonyl compounds.
- Torchy,Barbry
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p. 292 - 293
(2007/10/03)
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- Hydrogenation of amides by the use of bimetallic catalysts consisting of group 8 to 10, and group 6 or 7 metals
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Hydrogenation of amides can be catalyzed by bimetallic systems, which consist of Group 8 to 10 late transition-metals and Group 6 or 7 early transition-metals, under the mild conditions to afford the corresponding amines selectively in good to excellent yields.
- Hirosawa, Chitaru,Wakasa, Noriko,Fuchikami, Takamasa
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p. 6749 - 6752
(2007/10/03)
-
- Fast N-methylation of amines under microwave irradiation
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Primary and secondary amines are quickly N-methylated by methanal and formic acid under microwave irradiation.
- Barbry, Didier,Torchy, Severine
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p. 3919 - 3922
(2007/10/03)
-
- Study on the Effect of the Structure of the Leaving Group in the E1cb Mechanism of the Base-Promoted β-Elimination Reactions from N-alkylammonium Ions
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Studies of acid-base catalysis, H/D exchange, and solvent isotope effect on the β-elimination reactions with formation of p-nitrostyrene in acetohydroxamate/acetohydroxamic acid buffers at pH 9.05, H2O, μ = 1 M KCl, from N-alkylammonium ions with different leaving groups, such as N-methylpyrrolidine 1, N-ethylpyrrolidine 2, N-isopropylpyrrolidine 3, N-methylpiperidine 5, and N-methylazepane 6, show a change a partially reversible E1cb mechanism with 1, 2, and 4 to an irreversible E1cb mechanism with 3, 5, and 6.The change in the rate-determining step is related to the increased steric requirement of the leaving group.A steric acceleration from the carbanion intermediate to product step is proposed.
- Alunni, S.,Tijskens, P.
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p. 8371 - 8374
(2007/10/02)
-
- Structural and Mechanistic Effects on the Rates of Ring-Opening Reactions in the 5-16-Membered-Ring Region
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Partial rate coefficients have been determined for the reaction of cyclic dimethylammonium ions with sodium methoxide in the 7-16-membered-ring region.Three second-order parallel reactions take place and lead to exocyclic demethylation (A), ring-opening substitution (B), and ring-opening olefin-forming elimination (C).The results were compared with the behavior of the five- and six-membered rings.Reaction A shows negligible dependence on ring size.In contrast, reactions B and C are affected by ring size through ring strain and geometry of the transition state: the latter factor is held responsible for major differences in the reactivity profiles between such reactions.
- Cerichelli, Giorgio,Illuminati, Gabriello,Lillocci, Claudio
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p. 3952 - 3957
(2007/10/02)
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