- Synthesis of Unprotected 2-Arylglycines by Transamination of Arylglyoxylic Acids with 2-(2-Chlorophenyl)glycine
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The transamination of α-keto acids with 2-phenylglycine is an effective methodology for directly synthesizing unprotected α-amino acids. However, the synthesis of 2-arylglycines by transamination is problematic because the corresponding products, 2-arylglycines, transaminate the starting arylglyoxylic acids. Herein, we demonstrate the use of commercially available l-2-(2-chlorophenyl)glycine as the nitrogen source in the transamination of arylglyoxylic acids, producing the corresponding 2-arylglycines without interference from the undesired self-transamination process.
- Inada, Haruki,Shibuya, Masatoshi,Yamamoto, Yoshihiko
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p. 11047 - 11059
(2020/10/12)
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- Method for continuously and quickly preparing DL-phenylglycine and analogue thereof
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The invention provides a method for continuously and quickly preparing DL-phenylglycine and an analogue thereof. The method comprises the steps of adding 2-hydroxyl-phenylacetonitrile and an analoguethereof (cyanohydrin for short) and an aqueous ammonium bicarbonate solution into a microchannel reactor for a reaction, controlling the reaction temperature to be 80-130 DEG C, and controlling the reaction pressure to be 0.5-2.0 MPa, wherein the standing time of the reactants in a microchannel is 1-8 min, and an aqueous solution of 5-phenyl-hydantoin and an analogue thereof (hydantoin for short)is obtained; adding the hydantoin and alkali into the microchannel reactor for a reaction, controlling the reaction temperature to be 120-200 DEG C, and controlling the reaction pressure to be 1.0-3.5MPa, wherein the standing time of the reactants in the microchannel is 1-8 min, and then a saline solution of phenylglycine and an analogue thereof is obtained; conducting acidification neutralization and crystallization to obtain the phenylglycine and the analogue thereof. According to the method, the microchannel reactor is adopted, the reaction time is greatly shorted, the reaction speed is increased, pyrolysis and polymerization of the cyanohydrin are reduced, no by-products are generated, the products are high in yield, clean and environmentally friendly, and the production cost is lowered.
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- Preparation method for D, L-phenylglycine and analogue thereof
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The invention provides a preparation method for D, L-phenylglycine and an analogue thereof. According to the method, benzaldehyde, an analogue thereof and hydrocyanic acid are adopted as raw materials and subjected to cyanidation reaction, and then 2-hydroxy-benzyl cyanide or 2-hydroxy-benzyl cyanide analogue (cyanohydrin for short) is generated. Cyanohydrin reacts with carbon dioxide and the aqueous solution of ammonia, and then 5-phenyl-hydantoin and an analogue thereof (hydantoin for short) are generated. hydantoin is successively subjected to steam stripping, alkaline hydrolysis, steam stripping, decolorization, neutralization, crystallization, washing, centrifuging, drying and the like to obtain D, L-phenylglycine and the analogue thereof. Compared with the prior art, the preparation method for D, L-phenylglycine and the analogue thereof can significantly and effectively reduce the pollution, and fewer inorganic salt by-products are generated. Meanwhile, the prepared D, L-phenylglycine and the analogue thereof are high in product yield and high in purity. Counted in benzaldehyde and the analogue thereof, the yield of D, L-phenylglycine and the analogue thereof is larger than or equal to 96%, and the product purity is larger than or equal to 99%. Meanwhile, the process flow is simple and feasible, so that the method is worthy of market popularization and application.
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Paragraph 0037; 0038
(2017/03/17)
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- Ru-catalyzed C[sbnd]H functionalization of phenylglycine derivatives: Synthesis of isoquinoline-1-carboxylates and isoindoline-1-carboxylates
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The reaction of N-unprotected methylesters of phenylglycine derivatives (1a–1f) with electron-rich internal alkynes (2a–2e), catalyzed by [Ru(cymene)Cl2]2 (10%), gives the corresponding 3,4-disubstituted isoquinoline-1-carboxylates 3 through C[sbnd]H/N[sbnd]H oxidative coupling. The C[sbnd]H bond activation step is assisted by carboxylates, and N-fluoro-2,4,6-trimethylpyridinium triflate works as the terminal oxidant. The process shows a remarkable tolerance to the presence of diverse electron-releasing and electron-attracting functional groups at the phenyl ring of the amino acid. In addition, the reaction of phenylglycine derivatives (1a–1f) with methyl acrylate (4a) catalyzed by [Ru(cymene)Cl2]2 (10%) under the same experimental conditions, gives the corresponding 3,N-disubstituted isoindoline-1-carboxylates 5 through C[sbnd]H/N[sbnd]H coupling. Isoindolines 5 are obtained as a mixture of diastereoisomers, with moderate to high values of diastereomeric excess (up to 80%).
- Ruiz, Sara,Sayago, Francisco J.,Cativiela, Carlos,Urriolabeitia, Esteban P.
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p. 407 - 418
(2016/12/16)
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- CATALYST COMPOUNDS
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The present invention relates to an iridium-based catalyst compound for hydrogenating reducible moieties, especially imines and iminiums, the catalyst compounds being defined by the formulas: where ring B is either itself polycyclic, or ring B together with R is polycyclic. The catalysts of the invention are particularly effective in reductive amination procedures 10 which involve the in situ generation of the imine or iminium under reductive hydrogenative conditions.
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Paragraph 0314; 0324
(2015/03/28)
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- Primary amines by transfer hydrogenative reductive amination of ketones by using cyclometalated IrIII catalysts
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Cyclometalated iridium complexes are found to be versatile catalysts for the direct reductive amination (DRA) of carbonyls to give primary amines under transfer-hydrogenation conditions with ammonium formate as both the nitrogen and hydrogen source. These complexes are easy to synthesise and their ligands can be easily tuned. The activity and chemoselectivity of the catalyst towards primary amines is excellent, with a substrate to catalyst ratio (S/C) of 1000 being feasible. Both aromatic and aliphatic primary amines were obtained in high yields. Moreover, a first example of homogeneously catalysed transfer-hydrogenative DRA has been realised for β-keto ethers, leading to the corresponding β-amino ethers. In addition, non-natural α-amino acids could also be obtained in excellent yields with this method. Reduce the work! A broad range of ketones have been successfully aminated to afford primary amines under transfer-hydrogenation conditions by using ammonium formate as the amine source and 0.1 mol % of a cyclometalated IrIII catalyst (see scheme). Copyright
- Talwar, Dinesh,Salguero, Noemi Poyatos,Robertson, Craig M.,Xiao, Jianliang
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supporting information
p. 245 - 252
(2014/01/17)
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- CATALYST COMPOUNDS
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The present invention relates to an iridium-based catalyst compound for hydrogenating reducible moieties, especially imines and iminiums, the catalyst compounds being defined by the formulas: where ring B is either itself polycyclic, or ring B together with R is polycyclic. The catalysts of the invention are particularly effective in reductive amination procedures 10 which involve the in situ generation of the imine or iminium under reductive hydrogenative conditions.
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Paragraph 00163; 00173
(2013/11/05)
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- Synthesis, insecticidal and acaricidal activities of novel 2-arylpyrroles
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To search for novel 2-arylpyrroles with unique biological activities, a series of novel 2-arylpyrrole derivatives were designed and synthesized, and their structures were characterized by 1H and 13C NMR spectroscopy, MS spectrometry, and elemental analysis. Their insecticidal activities against Lepidopteran pests (e.g. Mythimna separata) and acaricidal activities against mites (e.g. Tetranychus urticae) were evaluated. The results of bioassays indicate that some of these title compounds exhibited excellent insecticidal and acaricidal activities. For example, 4-bromo-1-((chloromethoxy) methyl)-2-(4-chloro phenyl)-5-(trifluoromethyl)pyrrole-3-carbonitrile (6a), 4-bromo-2-(4-chlorophenyl)-1-((2-fluoroethoxy)-methyl)-5-(trifluoromethyl) pyrrole-3-carbonitrile (6d) showed insecticidal activity against Mythimna separata and 4-bromo-2-(4-chlorophenyl)-1-((isopropoxymethoxy)methyl)-5- (trifluoro methyl)pyrrole-3-carbonitrile (7d) showed acaricidal activity against Tetranychus urticae. They were more effective than Chlorfenapyr, which has been the only commercialized member of a new class of chemicals of 2-arylpyrroles.
- Liu, Aiping,Tang, Ming,Yu, Shuying,Liu, Xingping,Wang, Xiaoguang,Pei, Hui,Wu, Daoxin,Hu, Li,Ou, Xiaoming,Huang, Mingzhi
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p. 117 - 123
(2013/03/14)
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- Enhanced reduction of C-N multiple bonds using sodium borohydride and an amorphous nickel catalyst
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Amorphous nickel powder (Ni0) was utilised as a catalyst under mild, aqueous, basic conditions for enhancing the sodium borohydride-mediated reduction of C-N multiple bonds such as oximes, imines, hydrazones and nitriles to produce the corresponding amines in good to excellent yields.
- Liu, Shouxin,Yang, Yihua,Zhen, Xiaoli,Li, Junzhang,He, Huimin,Feng, Juan,Whiting, Andrew
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experimental part
p. 663 - 670
(2012/01/15)
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- Convenient method for reduction of C-N double bonds in oximes, imines, and hydrazones using sodium Borohydride-Raney ni system
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(Chemical Equation Presented) A practical method has been developed for reduction of C-N double bond in oximes, imines, and hydrazones with sodium borohydride catalyzed by Raney Ni. The reactions were carried out in basic aqueous solution, and the desired products were obtained in moderate yields after a simple procedure. This method can be applied to synthesize simpler aliphatic or aromatic amines and its analogs. Copyright Taylor & Francis Group, LLC.
- Yang, Yihua,Liu, Shouxin,Li, Junzhang,Tian, Xia,Zhen, Xiaoli,Han, Jianrong
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experimental part
p. 2540 - 2554
(2012/07/27)
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- Synthesis and κ binding affinity of 1-(pyrrolidin-1-ylmethyl)-2-(N-methyl)-4--1,2,3,4-tetrahydroisoquinolin-3(2H)-ones
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Diastereomeric forms of 1-(pyrrolidin-1-ylmethyl)-2-(N-methyl)-4--1,2,3,4-tetrahydroisoquinolin-3-(2H)-ones 3a and its chloro analog 3c were synthesized.Compounds 3a,c are related to the κ-selective opiate ICI 199441 1 by linking the benzylic CH2 to the ortho position of the phenyl in 1.Compared with morphine, these compounds had lost in κ and μ affinities; only cis-3a showed a modest κ affinity. 1-Pyrrolidin-1-ylmethyl-N--1,2,3,4-tetrahydroisoquinoline 2, which is also a cyclic congener of 1, was reported to display high κ and μ affinity, and so a conformational study was undertaken on 1, 2 and 3a.This showed that while active 2 extensively superposed on 1, 3a assumes another geometry which does now allow a fit with the pharmacophoric moieties of 1 and 2. tetrahydroisoquinolin-3(2H)-one / κ-opiate receptor / rigid congener
- Pinna, G. A.,Gavini, E.,Cignarella, G.,Scolastico, S.,Fadda, P.
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p. 515 - 520
(2007/10/02)
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- Mechanism of the Racemization of Amino Acids. Kinetics of Racemization of Arylglycines
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In a study of the rates of racemization of substituted arylglycines at pH 10, the Hammett ? value was found to be surprisingly low, 1.15, suggesting a concerted reaction or charge stabilization in a manner other than by the substituent.The rate of methine hydrogen exchange was, however, the same as the rate of racemization, which argues against a concerted reaction mechanism.A pH profile study demonstrated that the most reactive species was the zwitterion +NH3CH(C6H5)CO2-> in basic media.The racemization reaction showed general-base catalysis when the buffer concentration was changed at constant ionic strength.Within the aryl series, the entropy of activation was more significant than the enthalpy of activation.The ΔS(excit.) ranged from -24.5 to +29.0 eu, while ΔH(excit.) values ranged from 19.9 to 20.4 kcal.Racemization of arylglycines followed reversible first-order kinetics similar to that found for aliphatic amino acids in solution.The extent of racemization was studied as a function of pH.The details of the mechanism of this reaction are presented in light of these data.
- Smith, Grant Gill,Sivakua, Thipamon
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p. 627 - 634
(2007/10/02)
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- 7-α-Amino-substituted acylamino-3-(1-carboxymethyltetrazol-5-ylthiomethyl)-3-cephem-4-carboxylic acids
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Certain 7-acylamido-3-(1-carboxy-loweralkyl-tetrazol-5-ylthiomethyl)-3-cephem-4-carboxylic acids and their salts and easily hydrolyzed esters of the 4-carboxyl group were synthesized and found to be potent antibacterial agents which exhibited good aqueous solubility. In a preferred embodiment the 7-substituent was 2'-aminomethylphenylacetamido.
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