- Palladium-Catalyzed Reductive Aminocarbonylation of Benzylammonium Triflates with o-Nitrobenzaldehydes for the Synthesis of 3-Arylquinolin-2(1 H)-ones
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A palladium-catalyzed straightforward procedure for the synthesis of 3-arylquinolin-2(1H)-ones has been developed. The synthesis proceeds through a palladium-catalyzed reductive aminocarbonylation reaction of benzylic ammonium triflates with o-nitrobenzaldehydes, and a wide range of 3-arylquinolin-2(1H)-ones was obtained in moderate to good yields with very good functional group compatibility.
- Liu, Yongzhu,Qi, Xinxin,Wu, Xiao-Feng
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p. 13824 - 13832
(2021/10/12)
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- Heterogeneous Catalyzed Chemoselective Reductive Amination of Halogenated Aromatic Aldehydes
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The chemoselective conversion of a specific functional group in a multifunctional substrate is of great importance in the chemical industry to obtain cost efficient, sustainable and waste free processes. This work focuses on the chemoselective amination of halogenated aromatic aldehydes with dimethyl amine towards halogenated aromatic amines, a raw material used in the production of for example agrochemical active ingredients. It was found that by combining palladium, a metal known for dehalogenation reactions, and copper, known for its direct hydrogenation of aldehydes to alcohols, in one heterogeneous bimetallic catalyst, a synergistic effect is obtained. By depositing copper onto a palladium on carbon catalyst with a Cu/Pd ratio of at least 1 : 1, the yield could be increased from 66 % (Pd/C) to 98 % (PdCu/C). Moreover, this highly active and stable catalyst also showed suppressed dehalogenation side-reactions in several other chemical conversions such as hydrogenation of nitro functional groups and hydrogenation of aldehydes.
- Dumoleijn, Kim N. R.,Villa, Alberto,Marelli, Marcello,Prati, Laura,Moonen, Kristof,Stevens, Christian V.
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p. 3021 - 3026
(2021/05/18)
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- Simplified preparation of a graphene-co-shelled Ni/NiO@C nano-catalyst and its application in theN-dimethylation synthesis of amines under mild conditions
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The development of Earth-abundant, reusable and non-toxic heterogeneous catalysts to be applied in the pharmaceutical industry for bio-active relevant compound synthesis remains an important goal of general chemical research.N-methylated compounds, as one of the most essential bioactive compounds, have been widely used in the fine and bulk chemical industries for the production of high-value chemicals. Herein, an environmentally friendly and simplified method for the preparation of graphene encapsulated Ni/NiO nanoalloy catalysts (Ni/NiO@C) was developed for the first time, for the highly selective synthesis ofN-methylated compounds using various functional amines and aldehydes under easy to handle, and industrially applicable conditions. A large number of primary and secondary amines (more than 70 examples) could be converted to the correspondingN,N-dimethylamines with the participation of different functional aldehydes, with an average yield of over 95%. A gram-scale synthesis also demonstrated a similar yield when compared with the benchmark test. In addition, it was further proved that the catalyst could easily be recycled because of its intrinsic magnetism and reused up to 10 times without losing its activity and selectivity. Also, for the first time, the tandem synthesis ofN,N-dimethylamine products in a one-pot process, using only a single earth-abundant metal catalyst, whose activity and selectivity were more than 99% and 94%, respectively, for all tested substrates, was developed. Overall, the advantages of this newly developed method include operational simplicity, high stability, easy recyclability, cost-effectiveness of the catalyst, and good functional group compatibility for the synthesis ofN-methylation products as well as the industrially applicable tandem synthesis process.
- Liu, Jianguo,Ma, Longlong,Song, Yanpei,Zhang, Mingyue,Zhuang, Xiuzheng
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supporting information
p. 4604 - 4617
(2021/06/30)
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- Chemoselective Reduction of Tertiary Amides by 1,3-Diphenyl disiloxane (DPDS)
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A convenient procedure for the chemoselective reduction of tertiary amides at room temperature in the presence of air and moisture using 1,3-diphenyldisiloxane (DPDS) is developed. The reaction conditions tolerate a significant number of functional groups including esters, nitriles, secondary amides, carbamates, sulfoxides, sulfones, sulfonyl fluorides, halogens, aryl-nitro groups, and arylamines. The conditions reported are the mildest to date and utilize EtOAc, a preferred solvent given its excellent safety profile and lower environmental impact. The ease of setup and broad chemoselectivity make this method attractive for organic synthesis, and the results further demonstrate the utility of DPDS as a selective reducing agent.
- Aldrich, Courtney C.,Hammerstad, Travis A.,Hegde, Pooja V.,Wang, Kathleen J.
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- Hydrosilylative reduction of primary amides to primary amines catalyzed by a terminal [Ni-OH] complex
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A terminal [Ni-OH] complex1, supported by triflamide-functionalized NHC ligands, catalyzes the hydrosilylative reduction of a range of primary amides into primary amines in good to excellent yields under base-free conditions with key functional group tolerance. Catalyst1is also effective for the reduction of a variety of tertiary and secondary amides. In contrast to literature reports, the reactivity of1towards amide reduction follows an inverse trend,i.e., 1° amide > 3° amide > 2° amide. The reaction does not follow a usual dehydration pathway.
- Pandey, Pragati,Bera, Jitendra K.
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p. 9204 - 9207
(2021/09/20)
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- Zirconium-hydride-catalyzed site-selective hydroboration of amides for the synthesis of amines: Mechanism, scope, and application
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Developing mild and efficient catalytic methods for the selective synthesis of amines is a longstanding research objective. In this respect, catalytic deoxygenative amide reduction has proven to be promising but challenging, as this approach necessitates selective C–O bond cleavage. Herein, we report the selective hydroboration of primary, secondary, and tertiary amides at room temperature catalyzed by an earth-abundant-metal catalyst, Zr-H, for accessing diverse amines. Various readily reducible functional groups, such as esters, alkynes, and alkenes, were well tolerated. Furthermore, the methodology was extended to the synthesis of bio- and drug-derived amines. Detailed mechanistic studies revealed a reaction pathway entailing aldehyde and amido complex formation via an unusual C–N bond cleavage-reformation process, followed by C–O bond cleavage.
- Han, Bo,Jiao, Haijun,Wu, Lipeng,Zhang, Jiong
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p. 2059 - 2067
(2021/09/02)
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- Manganese-Catalyzed Hydroborations with Broad Scope
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Reductive transformations of easily available oxidized matter are at the heart of synthetic manipulation and chemical valorization. The applications of catalytic hydrofunctionalization benefit from the use of liquid reducing agents and operationally facile setups. Metal-catalyzed hydroborations provide a highly prolific platform for reductive valorizations of stable C=X electrophiles. Here, we report an especially facile, broad-scope reduction of various functions including carbonyls, carboxylates, pyridines, carbodiimides, and carbonates under very mild conditions with the inexpensive pre-catalyst Mn(hmds)2. The reaction could be successfully applied to depolymerizations.
- Ghosh, Pradip,Jacobi von Wangelin, Axel
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supporting information
p. 16035 - 16043
(2021/06/16)
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- Cu2O-catalyzed C–S coupling of quaternary ammonium salts and sodium alkane-/arene-sulfinates
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A new protocol for the synthesis of (enantioenriched) benzylic sulfones via the Cu2O-catalyzed C–S bond cross coupling of alkane-/arene-sulfinates and (enantioenriched) benzylic quaternary ammonium salts has been developed. The product benzylic sulfones were obtained in good to high yields (75–96%). Chiral arylmethyl sulfones with high enantiomeric excess (90–94% ee) were also synthesized in the presence of Cu2O and 1,1′-bis-(diphenylphosphino)ferrocene (dppf).
- Chen, Hongyi,Huang, Youming,Zeng, Qingle,Zheng, Wenting
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supporting information
(2020/08/28)
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- A Novel Route to Synthesize N,N-Dimethyl Arylmethylamines from Aryl Aldehydes, Hexamethylenetetramine and Hydrogen?
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Developing simple and green routes to access valuable chemicals is of significance. Herein, we present a green and novel route to synthesize N,N-dimethyl arylmethylamines (DAMAs) from hexamethylenetetramine (HMTA) and aryl aldehydes in the presence of hydrogen, and a series of DAMAs can be obtained in good yields. This approach opens the precedent for HMTA as N,N-dimethylamine source to synthesize chemicals with N,N-dimethylamine group, which has promising applications for N-containing chemicals synthesis.
- Ke, Zhengang,Yu, Bo,Wu, Yunyan,Zhao, Yanfei,Yang, Peng,Guo, Shien,Liu, Zhimin
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supporting information
p. 842 - 846
(2020/05/14)
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- Electrochemical Dehydrogenative Imidation of N-Methyl-Substituted Benzylamines with Phthalimides for the Direct Synthesis of Phthalimide-Protected gem-Diamines
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A general and green electrochemical dehydrogenative method for the imidation of N-methyl benzylamines with phthalimides with excellent regioselectivities is reported for the first time. This operationally simple method offers a valuable tool to obtain str
- Lian, Fei,Sun, Caocao,Xu, Kun,Zeng, Chengchu
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supporting information
p. 156 - 159
(2019/01/11)
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- Controlled Reduction of Carboxamides to Alcohols or Amines by Zinc Hydrides
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New protocols for controlled reduction of carboxamides to either alcohols or amines were established using a combination of sodium hydride (NaH) and zinc halides (ZnX2). Use of a different halide on ZnX2 dictates the selectivity, wherein the NaH-ZnI2 system delivers alcohols and NaH-ZnCl2 gives amines. Extensive mechanistic studies by experimental and theoretical approaches imply that polymeric zinc hydride (ZnH2)∞ is responsible for alcohol formation, whereas dimeric zinc chloride hydride (H?Zn?Cl)2 is the key species for the production of amines.
- Ong, Derek Yiren,Yen, Zhihao,Yoshii, Asami,Revillo Imbernon, Julia,Takita, Ryo,Chiba, Shunsuke
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supporting information
p. 4992 - 4997
(2019/03/13)
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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
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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
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p. 6084 - 6093
(2019/05/24)
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- Selective synthesis of mono- and di-methylated amines using methanol and sodium azide as C1 and N1 sources
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A Ru(ii) complex mediated synthesis of various N,N-dimethyl and N-monomethyl amines from organic azides using methanol as a methylating agent is reported. This methodology was successfully applied for a one-pot reaction of bromide derivatives and sodium azide in methanol. Notably, by controlling the reaction time several N-monomethylated and N,N-dimethylated amines were synthesized selectively. The practical applicability of this tandem process was revealed by preparative scale reactions with different organic azides and synthesis of an anti-vertigo drug betahistine. Several kinetic experiments and DFT studies were carried out to understand the mechanism of this transformation.
- Chakrabarti, Kaushik,Mishra, Anju,Panja, Dibyajyoti,Paul, Bhaskar,Kundu, Sabuj
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supporting information
p. 3339 - 3345
(2018/07/29)
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- Selective catalytic amination of halogenated aldehydes with calcined palladium catalysts
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This work focuses on understanding the influence of the conditions used in the calcination step of palladium catalysts on the performance of this catalyst in the reductive amination of halogen-containing substrates. The results show that increasing the calcination temperatures (from 100 °C to 400 °C) has a detrimental effect on catalytic activity but a strong positive effect on the selectivity (from 45 to 96%), avoiding the undesired dehalogenation reaction. TEM investigation showed that the reason for the different selectivity can be addressed to different Pd mean particles size and particle size distribution. In particular, larger Pd particles obtained at the highest calcination temperature (400 °C) showed the best selectivity to halogenated benzylamines (96%), with a good stability in terms of both activity and selectivity as confirmed by performing recycling tests.
- Villa, Alberto,Dumoleijn, Kim,Evangelisti, Claudio,Moonen, Kristof,Prati, Laura
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p. 15202 - 15206
(2018/04/30)
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- Visible-Light-Mediated α-Oxygenation of 3-(N,N-Dimethylaminomethyl)-Indoles to Aldehydes
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The visible-light-mediated oxygenation of 3-N,N-(dimethylaminomethyl)-indoles bearing various substituents afforded a series of 3-carbaindole derivatives. Herein we describe the reaction scope, a plausible mechanism and a practical application of this transformation in the formal synthesis of (–)-vincorine is described as well.
- Stanek, Filip,Paw?owski, Robert,Mlynarski, Jacek,Stodulski, Maciej
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supporting information
p. 6624 - 6628
(2018/10/20)
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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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- Direct Synthesis of N,N-Dimethylated and β-Methyl N,N-Dimethylated amines from nitriles using methanol: Experimental and computational studies
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Direct and selective synthesis of N,N-dimethylated amines from nitriles using methanol as C1 building blocks is reported using an air- and moisture-stable ruthenium complex. Following this process, various aromatic as well as aliphatic nitriles were converted to the corresponding N-methylated amines. Interestingly, tandem C-methylation as well as N-methylation was achieved by introducing multiple methyl groups. The practical aspect of this process was revealed by preparative-scale reactions with different nitriles and the synthesis of anti-allergic drug "avil". Several kinetic experiments and detailed DFT calculations were carried out to understand the mechanism of this process.
- Paul, Bhaskar,Shee, Sujan,Panja, Dibyajyoti,Chakrabarti, Kaushik,Kundu, Sabuj
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p. 2890 - 2896
(2018/04/14)
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- Lewis Acid-Catalyzed Reductive Amination of Aldehydes and Ketones with N,N-Dimethylformamide as Dimethylamino Source, Reductant and Solvent
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A practical zinc acetate dihydrate-catalyzed reductive amination of various carbonyl compounds with N,N-dimethylformamide (DMF) as dimethylamino (Me2N) source, reductant and solvent has been developed. This reaction shows broad substrate scope,
- Yang, Luo,Lin, Jie,Kang, Lei,Zhou, Wang,Ma, Da-You
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supporting information
p. 485 - 490
(2018/01/15)
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- Efficient and versatile catalytic systems for the n-methylation of primary amines with methanol catalyzed by n-heterocyclic carbene complexes of iridium
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Efficient and versatile catalytic systems were developed for the N-methylation of both aliphatic and aromatic primary amines using methanol as the methylating agent. Iridium complexes bearing an Nheterocyclic carbene (NHC) ligand exhibited high catalytic performance for this type of transformation. For aliphatic amines, selective N,N-dimethylation was achieved at low temperatures (50-90 °C). For aromatic amines, selective N-monomethylation and selective N,N-dimethylation were accomplished by simply changing the reaction conditions (presence or absence of a base with an appropriate catalyst). These findings can be used to develop methods for synthesizing useful amine compounds having N-methyl or N,N-dimethyl moieties.
- Toyooka, Genki,Tuji, Akiko,Fujita, Ken-Ichi
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p. 4617 - 4626
(2019/02/01)
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- Pd-Catalyzed Suzuki coupling reactions of aryl halides containing basic nitrogen centers with arylboronic acids in water in the absence of added base
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The Pd-catalyzed Suzuki coupling reactions of a series of aryl chlorides and aryl bromides containing basic nitrogen centers with arylboronic acids in water in the absence of added base are reported. The reactions proceed either partially or entirely under acidic conditions. After surveying twenty-two phosphorus ligands, high yields of products were obtained with aryl chlorides only when a bulky ligand, 2-(di-tert-butyl-phosphino)-1-phenyl-1H-pyrrole (cataCXiumPtB) was used. In contrast, aryl bromides produced high yields of products in the absence of both added base and added ligand. In order to explore the Suzuki coupling process entirely under acidic conditions, a series of reactions were conducted in buffered acidic media using several model substrates. 4-Chlorobenzylamine, in the presence of cataCXiumPtB, produced high yields of product at buffered pH 6.0; the yields dropped off precipitously at buffered pH 5.0 and lower. The fall-off in yield was attributed to the decomposition of the Pd-ligand complex due to the protonation of the ligand in the more acidic aqueous media. In contrast, in the absence of an added ligand, 4-amino-2-chloropyridine produced quantitative yields at buffered pH 3.5 and 4.5 while 4-amino-2-bromopyridine produced quantitative yields in a series of buffered media ranging from pH 4.5 to 1.5. These substrates are only partially protonated in acidic media and can behave as active Pd ligands in the Suzuki catalytic cycle.
- Li, Zhao,Gelbaum, Carol,Campbell, Zachary S.,Gould, Paul C.,Fisk, Jason S.,Holden, Bruce,Jaganathan, Arvind,Whiteker, Gregory T.,Pollet, Pamela,Liotta, Charles L.
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p. 15420 - 15432
(2017/12/15)
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- Ionic liquid/H2O-mediated synthesis of mesoporous organic polymers and their application in methylation of amines
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Mesoporous Tr?ger's base-functionalized polymers (Meso-TBPs) were prepared using a sulfonic acid group functionalized ionic liquid/H2O system, with surface areas up to 431 m2 g-1 and pore sizes of 3-15 nm. Ir(ii) coordinated Meso-TBPs exhibited extraordinary catalytic performance in the N-methylation of amines using methanol.
- Yu, Xiaoxiao,Yang, Zhenzhen,Zhang, Hongye,Yu, Bo,Zhao, Yanfei,Liiu, Zhenghui,Ji, Guipeng,Liu, Zhimin
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supporting information
p. 5962 - 5965
(2017/07/10)
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- Efficient Cobalt-Catalyzed Methylation of Amines Using Methanol
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The methylation of amines using methanol is a promising route to synthesize N-methylamines, and the development of cheap and efficient catalytic system for this reaction is of great significance. Herein, we reported a cobalt (Co)-based catalytic system, which was in situ formed from commercially available Co precursor and a tetradentate phosphine ligand P(CH2CH2PPh2)3 combined with K3PO4. This catalystic system was very effective for the selective production of dimethylated products from aliphatic amines and monomethylated ones from aromatic amines. The reaction mechanism was further investigated by control and isotope labelling experiments. (Figure presented.).
- Liu, Zhenghui,Yang, Zhenzhen,Yu, Xiaoxiao,Zhang, Hongye,Yu, Bo,Zhao, Yanfei,Liu, Zhimin
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supporting information
p. 4278 - 4283
(2017/10/23)
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- Graphene-enhanced platinum-catalysed hydrosilylation of amides and chalcones: A sustainable strategy allocated with in situ heterogenization and multitask application of H2PtCl6
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We describe a new sustainable strategy for the comprehensive utilization of a platinum catalyst in different organic transformations, in which an organosilicon/graphene-supported platinum catalyst prepared from a simple hydrosilylation-type reduction could be further used in the 1,4-hydrosilylation of chalcones. The rationally designed and in situ formed Pt@G@Si nanocatalyst is demonstrated to be highly effective in the 1,4-hydrosilylation of α,β-unsaturated enones, allowing for the facile synthesis of a variety of otherwise inaccessible substituted silyl enolates. In addition, with the aid of platinum catalyst residue and TBAF, the one-pot downstream Michael addition of substituted silyl enolates to alkyl acrylates is also reported in this work.
- Li, Ning,Dong, Xiao-Yun,Zhang, Jing-Lei,Yang, Ke-Fang,Zheng, Zhan-Jiang,Zhang, Wei-Qiang,Gao, Zi-Wei,Xu, Li-Wen
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p. 50729 - 50738
(2017/11/10)
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- Chemoselective Reduction of Tertiary Amides to Amines Catalyzed by Triphenylborane
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Triphenylborane (BPh3) was found to catalyze the reduction of tertiary amides with hydrosilanes to give amines under mild condition with high chemoselectivity in the presence of ketones, esters, and imines. N,N-Dimethylacrylamide was reduced to provide the α-silyl amide. Preliminary studies indicate that the hydrosilylation catalyzed by BPh3may be mechanistically different from that catalyzed by the more electrophilic B(C6F5)3.
- Mukherjee, Debabrata,Shirase, Satoru,Mashima, Kazushi,Okuda, Jun
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supporting information
p. 13326 - 13329
(2016/10/30)
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- Catalytic reduction of amides to amines by electrophilic phosphonium cations via FLP hydrosilylation
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A catalytic methodology for the conversion of amides to amines is reported. Of the 25 examples described, 14 examples involve the reduction of N-trifluoroacetamides to the corresponding trifluoroethylamines. These reductions are achieved by catalytic hydrosilylation of the amide mediated by an electrophilic phosphonium cation (EPC) catalyst.
- Augurusa, Alessandra,Mehta, Meera,Perez, Manuel,Zhu, Jiangtao,Stephan, Douglas W.
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supporting information
p. 12195 - 12198
(2016/10/21)
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- IMPROVED PROCESS FOR THE REDUCTIVE AMINATION AND SELECTIVE HYDROGENATION OF SUBSTRATES CONTAINING A SELECTED HALOGEN
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Disclosed is a process for performing a chemical reaction selected from reductive amination and hydrogenation of a first functional group in an organic feed substrate, which feed substrate comprises at least one further functional group containing a halogen atom, wherein the halogen atom is selected from the list consisting of chlorine, bromine, iodine, and combinations thereof, in the presence of hydrogen and a heterogeneous catalyst comprising at least one metal from the list of Pd, Rh, and Ru, together with at least a second metal from the list consisting of Ag, Ni, Co, Sn, Cu and Au. The process is preferably applied for the reductive amination of 2-chloro- benzaldehyde to form 2-chloro-benzyldimethylamine, as an intermediate in the production of agrochemically active compounds and microbiocides of the methoximinophenylglyoxylic ester series. Further disclosed is a composition rich in 2-chloro-benzyldimethylamine, further comprising an amount of 2- chloro-benzyl alcohol and being low in chlorotoluene isomers.
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Page/Page column 32
(2015/03/28)
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- METHOD FOR PRODUCING N-SUBSTITUTED AMINE COMPOUNDS THROUGH CATALYZED ALKYLATION
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The invention relates to a method for producing a N-substituted amine compound by catalyzed alkylation. The method uses amine and alcohol or two kinds of amines as the reaction materials, employs composite metal oxides catalyst at a reaction temperature of 80-180° C. to catalyze the reaction for 6-36 hours, so as to produce the N-substituted amine compound. The reaction condition of the method of the invention is relatively moderate, using a catalyst made of cheap non-noble metals, which is non-caustic and easy to be separated and reused. The reaction does not need any medium and has relatively high conversion rate and selectivity.
- -
-
Paragraph 0044
(2014/02/16)
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- Cu(II)-promoted palladium-catalyzed C-H ortho-arylation of N, N-dimethylbenzylamines
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A novel protocol for palladium-catalyzed arylation of the C(sp 2)-H bond directed by a N,N-dimethylaminomethyl group in the presence of AgOAc and Cu(OAc)2·H2O is described. Various aryl iodides proved to be efficient coupl
- Feng, Ruokun,Yao, Jinzhong,Liang, Zunjun,Liu, Zhanxiang,Zhang, Yuhong
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p. 3688 - 3696
(2013/06/04)
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- A general catalytic methylation of amines using carbon dioxide
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Putting CO2 to work: Carbon dioxide is shown to be a general and selective methylating reagent for secondary and primary, aromatic and aliphatic amines under reductive conditions. A variety of tertiary amines are obtained from CO2 and commercially available silanes in high yields with good tolerance to nitrile, olefin, ether, ester, and hydroxy groups. Copyright
- Li, Yuehui,Fang, Xianjie,Junge, Kathrin,Beller, Matthias
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supporting information
p. 9568 - 9571
(2013/09/23)
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- Development of a general non-noble metal catalyst for the benign amination of alcohols with amines and ammonia
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The N-alkylation of amines or ammonia with alcohols is a valuable route for the synthesis of N-alkyl amines. However, as a potentially clean and economic choice for N-alkyl amine synthesis, non-noble metal catalysts with high activity and good selectivity are rarely reported. Normally, they are severely limited due to low activity and poor generality. Herein, a simple NiCuFeOx catalyst was designed and prepared for the N-alkylation of ammonia or amines with alcohol or primary amines. N-alkyl amines with various structures were successfully synthesized in moderate to excellent yields in the absence of organic ligands and bases. Typically, primary amines could be efficiently transformed into secondary amines and N-heterocyclic compounds, and secondary amines could be N-alkylated to synthesize tertiary amines. Note that primary and secondary amines could be produced through a one-pot reaction of ammonia and alcohols. In addition to excellent catalytic performance, the catalyst itself possesses outstanding superiority, that is, it is air and moisture stable. Moreover, the magnetic property of this catalyst makes it easily separable from the reaction mixture and it could be recovered and reused for several runs without obvious deactivation. Copyright
- Cui, Xinjiang,Dai, Xingchao,Deng, Youquan,Shi, Feng
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supporting information
p. 3665 - 3675
(2013/03/29)
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- New catalyst systems for iron-catalyzed hydrosilane reduction of carboxamides
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A heptanuclear iron carbonyl cluster, [Fe3(CO) 11(μ-H)]2Fe(DMF)4 (4), is found to be a highly efficient catalyst for the reduction of various carboxamides by 1,2-bis(dimethylsilyl)benzene (BDSB), which makes possible reducing the amount of the catalyst, shortening the reaction time, and lowering the reaction temperatures.
- Tsutsumi, Hironori,Sunada, Yusuke,Nagashima, Hideo
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supporting information; experimental part
p. 6581 - 6583
(2011/07/08)
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- LiCl-Promoted Pd(ii)-catalyzed ortho carbonylation of N,N- dimethylbenzylamines
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Palladium-catalyzed highly regioselective carbonylation of substituted N,N-dimethylbenzylamines with the assistance of LiCl was developed. The ortho-functionalized N,N-dimethylbenzylamine was further transformed into ortho-methyl benzoate under mild conditions. These two transformations could be combined into one pot to produce the desired product in moderate yield. Applications of this methodology to synthesize the fragments of variolaric acid were also studied.
- Li, Hu,Cai, Gui-Xin,Shi, Zhang-Jie
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supporting information; experimental part
p. 10442 - 10446
(2011/01/08)
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- Remarkable enhancement effect of potassium tert-butoxide/THF solution in base-induced Sommelet-Hauser rearrangements
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A solution of potassium tert-butoxide in THF was shown to remarkably enhance the base-induced Sommelet-Hauser rearrangement of N-benzylic amino acid-derived ammonium ylides.
- Tayama, Eiji,Takedachi, Keisuke,Iwamoto, Hajime,Hasegawa, Eietsu
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supporting information; experimental part
p. 9389 - 9395
(2011/01/12)
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- Superelectrophilic intermediates in nitrogen-directed aromatic borylation
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The first examples of borylation under conditions of borenium ion generation from hydrogen-bridged boron cations are described. The observable H-bridged cations are generated by hydride abstraction from N,N-dimethylamine boranes Ar(CH2)nNMe2BH3 using Ph3C+ (C6F5)4B - (TrTPFPB) as the hydride acceptor. In the presence of excess TrTPFPB, the hydrogen-bridged cations undergo internal borylation to afford cyclic amine borane derivatives with n = 1-3. The products are formed as the corresponding cyclic borenium ions according to reductive quenching experiments and 11B and 1H NMR spectroscopy in the case with Ar = C6H5 and n = 1. The same cyclic borenium cation is also formed from the substrate with Ar = o-C6H4SiMe3 via desilylation, but the analogous system with Ar = o-C6H 4CMe3 affords a unique cyclization product that retains the tert-butyl substituent. An ortho-deuterated substrate undergoes cyclization with a product-determining isotope effect of kH/kD 2.8. Potential cationic intermediates have been evaluated using B3LYP/6-31G* methods. The computations indicate that internal borylation from 14a occurs via a C-H insertion transition state that is accessible from either the borenium π complex or from a Wheland intermediate having nearly identical energy. The Ar = o-C6H4SiMe3 example strongly favors formation of the Wheland intermediate, and desilylation occurs via internal SiMe3 migration from carbon to one of the hydrides attached to boron.
- De Vries, Timothy S.,Prokofjevs, Aleksandrs,Harvey, Jeremy N.,Vedejs, Edwin
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supporting information; experimental part
p. 14679 - 14687
(2010/01/06)
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- Practical access to amines by platinum-catalyzed reduction of carboxamides with hydrosilanes: Synergy of dual Si-H groups leads to high efficiency and selectivity
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The synergetic effect of two Si-H groups leads to efficient reduction of carboxamides to amines by platinum catalysts under mild conditions. The rate of the reaction is dependent on the distance of two Si-H groups; 1,1,3,3-tetramethyldisiloxane (TMDS) and 1,2-bis(dimethylsilyl)benzene are found to be an effective reducing reagent. The reduction of amides having other reducible functional groups such as NO2, CO2R, CN, CdC, Cl, and Br moieties proceeds with these groups remaining intact, providing a reliable method for the access to functionalized amine derivatives. The platinum-catalyzed reduction of amides with polymethylhydrosiloxane (PMHS) also proceeds under mild conditions. The reaction is accompanied by automatic removal of both platinum and silicon wastes as insoluble silicone resin, and the product is obtained by simple extraction. A mechanism involving double oxidative addition of TMDS to a platinum center is discussed.
- Hanada, Shiori,Tsutsumi, Emi,Motoyama, Yukihiro,Nagashima, Hideo
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supporting information; experimental part
p. 15032 - 15040
(2010/01/29)
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- Hydrosilane reduction of tertiary carboxamides by iron carbonyl catalysts
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Fox in the carboxamide: Reduction of tertiary carboxamides to their corresponding amines is catalyzed by [Fe(CO)5] or [Fe 3(CO)12], using 1,1,3,3tetramethyldlsiloxane (TMDS) as the reducing agent. The reaction proceeds under either thermal or photochemical conditions. Unlike the hydrosilane reduction of amides using platinum or ruthenlum catalysts, TMDS preferentially reduces a nitro group, even in the presence of competing amides.
- Sunada, Yusuke,Kawakami, Hiroko,Imaoka, Tsuyoshi,Motoyama, Yukihiro,Nagashima, Hideo
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supporting information; experimental part
p. 9511 - 9514
(2010/03/24)
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- Indirect ortho functionalization of substituted toluenes through ortho olefination of N,N-dimethylbenzylamines tuned by the acidity of reaction conditions
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Highly regioselective olefination of substituted N,N-dimethylbenzylamines was developed by tuning the acidity of reaction conditions based on analysis of their features. The ortho-functionalized N,N-dimethylbenzylamines were further transformed into 3-(2′
- Cai, Guixin,Fu, Ye,Li, Yizhou,Wan, Xiaobing,Shi, Zhangjie
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p. 7666 - 7673
(2008/02/09)
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- Synthesis of quaternary salts of ammonia from cinnamic acids and their plant growth retardant activity
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A series of N,N-dimethyl-N-benzyl ammonium chloride cinnamides (1a-e) were prepared from the reaction between cinnamyl chlorides (4a-e) and N,N-dimethylphenylmethanamines (6a-e). These salts were tested for their biological activity on germination, seedling growth and adventitious root formation on hypocotyl cuttings of Vigina radiata (SML-668) and were found to be markedly inhibit germination and seedling growth of mungbean seeds under laboratory conditions.
- Sharma,Kaur, Sukhvir
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p. 612 - 614
(2008/12/20)
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- Dual Si-H effects in platinum-catalyzed silane reduction of carboxamides leading to a practical synthetic process of tertiary-amines involving self-encapsulation of the catalyst species into the insoluble silicone resin formed
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Combination of commercially available platinum catalysts with siloxanes containing more than two Si-H groups is found to be an efficient catalyst system for the reduction of carboxamides to amines. In particular, facile removal of silicon and platinum residues from the product can be achieved by the use of polymethylhydrosiloxanes as reducing reagents.
- Hanada, Shiori,Motoyama, Yukihiro,Nagashima, Hideo
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p. 6173 - 6177
(2007/10/03)
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- Aminoborohydrides. 12. Novel tandem SNAr amination-reduction reactions of 2-halobenzonitriles with lithium N,N-dialkylaminoborohydrides
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A novel tandem amination-reduction reaction has been developed in which 2-(N,N-dialkylamino)benzylamines are generated from 2-halobenzonitriles and lithium N,N-dialkylaminoborohydride (LAB) reagents. These reactions are believed to occur through a tandem SNAr amination-reduction mechanism wherein the LAB reagent promotes halide displacement by the N,N-dialkylamino group, and the nitrile is subsequently reduced. This one-pot procedure is complimentary to existing synthetic methods and is an attractive synthetic tool for the nucleophilic aromatic substitution of halobenzenes with less nucleophilic amines. The (N,N-dialkylamino)benzylamine products of this reaction are easily isolated after a simple aqueous workup procedure in very good to excellent yields.
- Thomas,Collins,Cuzens,Spiciarich,Goralski,Singaram
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p. 1999 - 2004
(2007/10/03)
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- Thermodynamics, kinetics, and mechanism of exchange of cyclopalladated ligands
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The exchange between cyclopalladated complexes and free ligands has been studied in acetic acid. An equilibrium study of the system based on N,N-dimethylbenzylamine derivatives [PdX(YZC6H2CH2NMe2)]2 + 2C6D5CD2NMe2 ? [PdX-(C6D4CD2NMe2)]2 + 2YZC6H2DCH2NMe2 (K1) has revealed that Pd(II) binds preferably with the electron-poorest ligand at equilibrium; K1 is 114, 0.59, 0.125, 0.008, and 0.0034 for 4-Y (5-Z) = MeO (MeO), H (Me), H (H), H (Cl), and H (NO2), respectively, at 55°C in D3CCOOD/CDCl3, X = MeCO2-. A procedure for regioselective ortho palladation of bifunctional derivatives such as 1-(3,4-dimethoxyphenyl)-2-methyl-3-(4-nitrophenyl)-2-azapropane (7) is put forward. In aprotic chloroform, Pd(II) acetate metalates the electron-rich ring of 7 to yield 8a, but the electron-poor ring is ortho palladated in acetic acid to yield 9a. A dissociative exchange mechanism is proposed on the basis of a kinetic study of reactions between [PdX-(YZC6H2CH2NMe2)]2 and 2-phenylpyridine or azobenzene to afford the corresponding cyclopalladated complexes. Preequilibrium measurements have indicated that in the former case the reactive species are monomers formed via acetate-bridge cleavage by 2-phenylpyridine but in the latter case the complexes react as dimers. Despite this, all of the reactions are first order in complex and zero order in entering ligand. The rate constants of the 2-phenylpyridine case at 75°C are (104k) 12.6, 3.9, 2.35, 2.6, 0.44, and 0.0225 s-1 for 4-Y (5-Z) = MeO (MeO), H (Me), H (H), H (MeO), H (Cl), and H (NO2), respectively. On the basis of substituent and solvent kinetics isotope effects, values of activation parameters, and data obtained previously, it has been suggested that cleavage of the Pd-N bond of the leaving ligand occurs first, followed by acidolysis of the Pd-C bond. Both steps can contribute to the overall rate. The two are followed by the rapid activation of the C-H bond of the incoming ligand. Reasons for the pseudonucleophilic behavior of Pd(II) toward C-H bonds of benzylamines in acetic acid have been evaluated on the basis of the proposed mechanism.
- Ryabov, Alexander D.
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p. 1252 - 1260
(2008/10/08)
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- 2-Pyrazolyl-benzophenones
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2-Pyrazolyl-benzophenones, e.g. those of the formula STR1 R = H or alkyl Ro = H, alkyl, (HO, alkoxy, amino)-alkyl, aralkyl, or aryl R', r" = h, alkyl, alkoxy, halo or CF3 Am = open or cyclic amino Corresponding ketals, or therapeutically useful acid addition salts thereof exhibit antianxiety and antidepressant effects.
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- 2-Pyrazolyl-benzophenones
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2-Pyrazolyl-benzophenones, e.g. those of the formula STR1 CORRESPONDING KETALS, CARBINOLS, ACYL DERIVATIVES OR THERAPEUTICALLY USEFUL ACID ADDITION SALTS THEREOF EXHIBIT ANTIANXIETY AND ANTI-DEPRESSANT EFFECTS.
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- Pyrazolobenzazepines
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6-Aryl-1- or 2H,4H-pyrazolo[4,3-d](2)-benzazepines, e.g. those of the formula STR1 R = H or alkyl R° = H, alkyl, (HO, alkoxy, amino)-alkyl, aralkyl, aryl or acyl, R' = h, oh or alkyl R" = h, alkyl, alkoxy, halo or CF3 N-oxides thereof or therapeutically useful acid addition salts of such compounds exhibit antianxiety and antidepressant effects.
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- Pyrazolobenzazepines
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6-Aryl-1- or 2H,4H-pyrazolo[4,3-d](2) -benzazepines, e.g. those of the formula STR1 N-oxides thereof or therapeutically useful acid addition salts of such compounds exhibit antianxiety and antidepressant effects.
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- Pyrazolobenzazepines
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6-Aryl-1 or 2H,4H-pyrazolo[4,3-d](2)-benzazepines, e.g. those of the formula SPC1 R = h or alkyl Ro = H, alkyl, (HO, alkoxy, amino)-alkyl, aralkyl or aryl R' = h, oh or alkyl R" = h, alkyl, alkoxy, halo or CF3 5,6-dihydro- or 5-alkyl
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- Antidepressive and antianxiety composition comprising 2-pyrazolyl-benzophenones
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2-Pyrazolyl-benzophenones, e.g. those of the formula SPC1 Ro = H, alkyl, (HO, alkoxy, amino)- alkyl, aralkyl or aryl R = h or alkyl R',r" = h, alkyl,alkoxy, halo or CF3 Am = open or cyclic amino group Corresponding ketals, carbinols,
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