- Catalytic Activity of Some Bifunctional Compounds on the Hydrolysis of a Nitrile Group; a New Effective Method for Hydrolysis of α-Aminophenylacetonitrile to Phenylglycinamide
-
Various bifunctional compounds, 2-mercaptoethanol, glutathione, cysteine, and ethane-1,2-dithiol showed catalytic activity on the hydrolysis of the nitrile group of α-aminophenylacetonitrile.
- Goo, Yang M.,Lee, Young B.
-
-
Read Online
- Asymmetric Transformation of (RS)-2-Phenylglycine via Formation of Salt with (1S)-10-Camphorsulfonic Acid
-
An asymmetric transformation of (RS)-2-phenylglycine was carried out via formation of a salt with (1S)-10-camphorsulfonic acid in acetic acid, propanoic acid, or butanoic acid by heating at 100 deg C without using any catalysts such as aldehydes.The rate of epimerization of a more soluble salt of (S)-Phg with (S)-CS was estimated to be the lowest in acetic acid and highest in butanoic acid.The asymmetric transformation in propanoic acid, however, was achieved successfully to give the salt of (R)-Phg with (S)-CS with 100percent optical purity in 82percent yield.Optically pure (R)-Phg was obtained from the salt in 80percent yield based on the (RS)-Phg used as the starting material.
- Shiraiwa, Tadashi,Sakata, Shinji,Fujishima, Keiko,Kurokawa, Hidemoto
-
-
Read Online
- Design, synthesis, and biological activities of novel 2-alkylpyrrole derivatives
-
To investigate the alkyl analog of insecticide chlorfenapyr, two series of 2-alkyl-4-bromo-5-(trifluoromethyl)pyrrole-3-carbonitriles were synthesized with a cycloaddition as the key step. The target products were characterized by 1H-NMR spectroscopy, elemental analysis, or HRMS. The insecticidal, herbicidal, and antifungal activities of the target compounds were evaluated and found that these compounds did not show much insecticidal activity, but compounds 4, 10, and 11 had very good fungicidal activities against Alternaria solani and Fusarium oxysporum. Moreover, compound 4 had an outstanding inhibition effect against pigweed.
- Li, Yongqiang,Wang, Ziwen,Zhang, Pengxiang,Liu, Yuxiu,Xiong, Lixia,Wang, Qingmin
-
-
Read Online
- Optical Resolution by Preferential Crystallization of 1,1,3,3-Tetramethylbutylammonium Salt of N-Formyl-DL-α-phenylglycine
-
Infrared spectrum, solubility, and ternary phase diagram of solubility indicated that 1,1,3,3-tetramethylbutylammonium salt (DL-TMB salt) of N-formyl-DL-α-phenylglycine is a conglomerate.In order to resolve DL-TMB salt efficiently, crystallization of D- and L-TMB salts was examined by free energy of critical nucleation in supersaturated solutions.Successive preferential crystallization of DL-TMB salt was experimented at 10 deg C for racemic solution in ethanol with the degree of supersaturation of 130percent, and D- and L-α-phenylglycine with 100percent optical purity were obtained from pure D- and L-TMB salts.
- Shiraiwa, Tadashi,Miyazaki, Hideya,Imai, Tomoki,Sunami, Michio,Kurokawa, Hidemoto
-
-
Read Online
- Development of anti-inflammatory peptidomimetics based on the structure of human alpha1-antitrypsin
-
Human α1-antitrypsin (hAAT) has two distinguishing functions: anti-protease activity and regulation of the immune system. In the present study we hypothesized that those two protein functions are mediated by different structural domains on the hAAT surface. Indeed, such biologically active immunoregulatory sites (not associated with canonical anti-protease activity) on the surface of hAAT were identified by in silico methods. Several peptides were derived from those immunoregulatory sites. Four peptides exhibited impressive biological effects in pharmacological concentration ranges. Peptidomimetic (14) was developed, based on the structure of the most druggable and active peptide. The compound exhibited a potent anti-inflammatory activity in vitro and in vivo. Such a compound could be used as a basis for developing novel anti-inflammatory drug candidates and as a research tool for better understanding hAAT functions.
- Lior, Yotam,Shtriker, Efrat,Kahremany, Shirin,Lewis, Eli C.,Gruzman, Arie
-
supporting information
(2021/11/16)
-
- Direct reductive amination of ketones with ammonium salt catalysed by Cp*Ir(iii) complexes bearing an amidato ligand
-
A series of half-sandwich Ir(iii) complexes1-6bearing an amidato bidentate ligand were conveniently synthesized and applied to the catalytic Leuckart-Wallach reaction to produce racemic α-chiral primary amines. With 0.1 mol% of complex1, a broad range of ketones, including aryl ketones, dialkyl ketones, cyclic ketones, α-keto acids, α-keto esters and diketones, could be transformed to their corresponding primary amines with moderate to excellent yields (40%-95%). Asymmetric transformation was also attempted with chiral Ir complexes3-6, and 16% ee of the desired primary amine was obtained. Despite the unsatisfactory enantio-control achieved so far, the current exploration might stimulate more efforts towards the discovery of better chiral catalysts for this challenging but important transformation.
- Dai, Zengjin,Pan, Ying-Min,Wang, Shou-Guo,Yin, Qin,Zhang, Xumu
-
supporting information
p. 8934 - 8939
(2021/11/04)
-
- Synthesis of Unprotected 2-Arylglycines by Transamination of Arylglyoxylic Acids with 2-(2-Chlorophenyl)glycine
-
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
-
p. 11047 - 11059
(2020/10/12)
-
- Validated HPLC and stability-indicating densitometric chromatographic methods for simultaneous determination of camylofin dihydrochloride and paracetamol in their binary mixture
-
Two accurate, sensitive, precise and selective HPLC and stability-indicating TLC methods were developed for the simultaneous determination of camylofin-2HCl and paracetamol. Forced acid, alkali and oxidative degradation of camylofin-2HCl?were tried where complete degradation was achieved using 5?N HCl. HPLC method was developed to determine the mixture of the two drugs using Zorbax NH2 column and a mobile phase of 0.5percent triethylamine and pH 3.0 adjusted with 0.1percent phosphoric acid and methanol (70:30 v/v) over concentration ranges of 3–90 and 10–95?μg/mL for camylofin-2HCl and paracetamol, respectively.TLC method was used for the separation of camylofin from its acid degradate and paracetamol using chloroform–methanol–acetone–conc. ammonia (8:2:2:0.1, by volume) as developing system and band scanning at 254 nm over concentration ranges of 5–40?μg/band for camylofin-2HCl and 0.1–0.5?μg/band for paracetamol. The validation of two methods was carried out according to ICH guideline. Accuracy ranged between 98.47 and 100.67percent for the two methods with acceptable precision RSDpercent ranging between 0.66 and 1.47percent.
- Abdel Razeq, Sawsan A.,Khalil, Israa A.,Mohammd, Samah A.
-
p. 2587 - 2597
(2020/06/17)
-
- Novel synthetic method of D/L-phenyl glycine
-
The invention relates to a novel synthetic method of D/L-phenyl glycine. An existing synthetic method of D/L-phenylglycine is used for producing D/L-phenyl glycine by using highly toxic raw materials,and the synthetic method is harmful. According to the synthesis method, benzene is used as a solvent and a raw material. The method comprises the following steps: firstly, performing Friedel-Crafts alkylation reaction between benzene and dichloroacetic acid or bromochloroacetic acid under the catalystic function of a catalyst, wherein the reaction temperature of Friedel-Crafts alkylation reactionis 55-60 DEG C, the reaction time is 7h, and after Friedel-Crafts alkylation reaction, a benzene solution of alpha-chlorophenylacetic acid or alpha-bromophenylacetic acid is obtained; separating thereaction product into a water phase by using 20% ammonia water; adding urotropin into the water phase to carry out catalytic reactions at a temperature of 75-80 DEG C for 12 hours, controlling the temperature to be 70-80 DEG C, neutralizing the solution by 30% sulfuric acid until the pH value is equal to 6.5 to obtain a D/L-phenyl glycine water solution, and performing suction filtration to obtaina filter cake, namely D/L-phenyl glycine. Cyanide is not used, production is safe, energy consumption is reduced, and the raw material quality standard of downstream products is met.
- -
-
Paragraph 0022-0025
(2020/04/22)
-
- Reductive amination of ketonic compounds catalyzed by Cp*Ir(III) complexes bearing a picolinamidato ligand
-
Cp*Ir complexes bearing a 2-picolinamide moiety serve as effective catalysts for the direct reductive amination of ketonic compounds to give primary amines under transfer hydrogenation conditions using ammonium formate as both the nitrogen and hydrogen source. The clean and operationally simple transformation proceeds with a substrate to catalyst molar ratio (S/C) of up to 20,000 at relatively low temperature and exhibits excellent chemoselectivity toward primary amines.
- Tanaka, Kouichi,Miki, Takashi,Murata, Kunihiko,Yamaguchi, Ayumi,Kayaki, Yoshihito,Kuwata, Shigeki,Ikariya, Takao,Watanabe, Masahito
-
p. 10962 - 10977
(2019/09/03)
-
- Method for continuously and quickly preparing DL-phenylglycine and analogue thereof
-
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.
- -
-
Paragraph 0025-0030
(2019/07/04)
-
- A cyanohydrin continuous method for rapid preparation DL - phenyl glycine and its analogue
-
The present invention provides a cyanohydrin continuous method for rapid preparation DL - phenyl glycine and its similar method, including: (1) ammoniation reaction: the 2 - hydroxy - benzyl cyanide and the like (hereinafter referred to as the cyanohydrin) with ammonia water fed to the microchannel reactor to carry out the reaction, the reaction temperature is controlled 50 - 200 °C, pressure is 0.5 - 2.5 mpa, the reactant in the residence time in the micro channel is 0.5 - 8 min, to obtain 2 - amino - benzyl cyanide and the like (hereinafter referred to as melamine) aqueous solution; (2) alkaline hydrolysis reaction: step (1) of the melamine obtained with the alkali are fed to the microchannel reactor to carry out the reaction, the reaction temperature is controlled 90 - 200 °C, pressure is 1.0 - 3.0 mpa, the reactant in the dwell time in the micro channel for 10 - 60 minutes, to obtain DL - phenyl glycine and analogs thereof. The invention adopts the micro-channel reactor, accelerate the ammoniation and alkaline hydrolysis reaction rate, reduces the cyanohydrin and melamine pyrolytic-polymerization, without catalyst, improves the yield of the product, the production cost is reduced.
- -
-
Paragraph 0027; 0030; 0033; 0036; 0039; 0042; 0045; 0048
(2019/07/04)
-
- Catalytic Conversion of Alcohols to Carboxylic Acid Salts and Hydrogen with Alkaline Water
-
A [RuH(CO)(py-NP)(PPh3)2]Cl (1) catalyst is found to be effective for catalytic transformation of primary alcohols, including amino alcohols, to the corresponding carboxylic acid salts and two molecules of hydrogen with alkaline water. The reaction proceeds via acceptorless dehydrogenation of alcohol, followed by a fast hydroxide/water attack to the metal-bound aldehyde. A pyridyl-type nitrogen in the ligand architecture seems to accelerate the reaction.
- Sarbajna, Abir,Dutta, Indranil,Daw, Prosenjit,Dinda, Shrabani,Rahaman, S. M. Wahidur,Sarkar, Abheek,Bera, Jitendra K.
-
p. 2786 - 2790
(2017/05/31)
-
- Photoredox activation of carbon dioxide for amino acid synthesis in continuous flow
-
Although carbon dioxide (CO 2) is highly abundant, its low reactivity has limited its use in chemical synthesis. In particular, methods for carbon-carbon bond formation generally rely on two-electron mechanisms for CO 2 activation and require highly activated reaction partners. Alternatively, radical pathways accessed via photoredox catalysis could provide new reactivity under milder conditions. Here we demonstrate the direct coupling of CO 2 and amines via the single-electron reduction of CO 2 for the photoredox-catalysed continuous flow synthesis of α-Amino acids. By leveraging the advantages of utilizing gases and photochemistry in flow, a commercially available organic photoredox catalyst effects the selective α-carboxylation of amines that bear various functional groups and heterocycles. The preliminary mechanistic studies support CO 2 activation and carbon-carbon bond formation via single-electron pathways, and we expect that this strategy will inspire new perspectives on using this feedstock chemical in organic synthesis.
- Seo, Hyowon,Katcher, Matthew H.,Jamison, Timothy F.
-
p. 453 - 456
(2017/05/05)
-
- CATALYST COMPOUNDS
-
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.
- -
-
Paragraph 0314; 0324
(2015/03/28)
-
- Primary amines by transfer hydrogenative reductive amination of ketones by using cyclometalated IrIII catalysts
-
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
-
supporting information
p. 245 - 252
(2014/01/17)
-
- Synthesis of arylglycines from CO2 through α-amino organomanganese species
-
In the presence of three readily available chemicals, Mn powder, BF 3·OEt2, and LiCl, N-acyl-N,O-acetals were successfully converted into the corresponding α-amino acids (arylglycine derivatives) under 1 atm of a CO2 atmosphere in high yields. The LiCl additive is necessary in order to increase the solubility and the nucleophilicity of an organomanganese intermediate. The products thus obtained were transformed into free α-amino acids in two steps.
- Mita, Tsuyoshi,Chen, Jianyang,Sato, Yoshihiro
-
p. 2200 - 2203
(2014/05/06)
-
- CATALYST COMPOUNDS
-
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.
- -
-
Paragraph 00163; 00173
(2013/11/05)
-
- Biocatalytic asymmetric synthesis of unnatural amino acids through the cascade transfer of amino groups from primary amines onto keto acids
-
Flee to the hills: An unfavorable equilibrium in the amino group transfer between amino acids and keto acids catalyzed by α-transaminases was successfully overcome by coupling with a ω-transaminase reaction as an equilibrium shifter, leading to efficient asymmetric synthesis of diverse unnatural amino acids, including L-tert-leucine and D-phenylglycine. Copyright
- Park, Eul-Soo,Dong, Joo-Young,Shin, Jong-Shik
-
p. 3538 - 3542
(2014/01/06)
-
- Ethyl 2,2-bis(4-methylphenylsulfonamido)acetate to aromatic α-amino acids: Stable substrates for catalytic arylation reactions
-
This paper reports the development of a novel methodology for the catalytic synthesis of aromatic α-amino acids, which involves the addition of aryl-organoboron reagents to α,α-ditosylamino esters derived from ethyl glyoxylate, using transition metal catalysts, like Rh and Pd. A library of α-amino esters (12 with Pd and 8 with Rh), was synthesized with moderate to excellent yields. A highest enantioselectivity of 30% ee was obtained using Hayashi's ligand. This method was applied to the synthesis of phenylglycine.
- Marques, Carolina S.,Burke, Anthony J.
-
supporting information
p. 10091 - 10097
(2013/11/06)
-
- Thermal recording material
-
A thermal recording material comprises a support and a thermal recording layer formed thereon, the thermal recording layer containing an electron-donating dye precursor and an electron-receiving developer that causes said dye precursor to develop a color, wherein said thermal recording layer contains vapor-phase synthesis silica, preferably, the vapor-phase synthesis silica has a specific surface area, measured by a BET method, of 50 to 200 m2/g and further is doped with aluminum oxide, and the thermal recording layer further contains the above vapor-phase synthesis silica and a diphenyl sulfones-bridged type compound, and the thermal recording material is excellent in anti-sticking property and image stability.
- -
-
-
- Enhanced reduction of C-N multiple bonds using sodium borohydride and an amorphous nickel catalyst
-
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
-
experimental part
p. 663 - 670
(2012/01/15)
-
- Convenient method for reduction of C-N double bonds in oximes, imines, and hydrazones using sodium Borohydride-Raney ni system
-
(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
-
experimental part
p. 2540 - 2554
(2012/07/27)
-
- METHOD FOR PRODUCING A RADIOPHARMACEUTICAL
-
A method produces a radiopharmaceutical. In the method, an H—Li exchange is made by adding an alkyllithium to an isocyanide, wherein the α-H atom of the isocyanide is replaced with an Li atom. 11CO2 is added and bonded to the α-C atom of the isocyanide. By a two-stage hydrolysis, the Li atom is replaced with an H atom and an amino group is formed from the isocyanide group, for example, by adding NH4Cl and HI. The reaction is continuously performed in particular in a microfluidic structure so that reaction times of less than 300 seconds can be achieved for the partial steps. Because the produced radiopharmaceutical has only a low half-life, the short production time has a positive effect on the yield of radioactive pharmaceutical.
- -
-
Page/Page column 2-3
(2012/06/16)
-
- NOVEL ORGANIC METAL COMPLEX AND PROCESS FOR PREPARING AMINE COMPOUND
-
[Problem] The present invention aims to provide a novel organometallic compound that can be used as a general-use highly active catalyst with superior selectivity for functional groups. [Means for Solving Problem] The present invention relates to an organometallic compound having a novel specific structure of general formula (1): and to a general-use highly active catalyst used in reductive amination reaction with superior selectivity for functional groups that comprises said organometallic compound, and to a process for preparing amine compounds by reductive amination reaction using said catalyst.
- -
-
Page/Page column 14
(2010/09/18)
-
- Direct, facile synthesis of N-acyl-α-amino amides from α-keto esters and ammonia
-
N-Acyl-α-amino amides were prepared, without the necessity of chromatographic purification, in a single step by heating the corresponding α-keto ester in methanolic ammonia. The Royal Society of Chemistry.
- Ntaganda, Rukundo,Milovic, Tamara,Tiburcio, Jorge,Thadani, Avinash N.
-
scheme or table
p. 4052 - 4054
(2009/03/11)
-
- Asymmetric synthesis of amino acids by Cr(II) complexes of natural amino acids
-
Stoichiometric reduction of the C,N double bond of oxime precursors of α-amino acids was performed in aqueous media by Cr(II) complexes of natural amino acids. The reduction of oximes of α-ketophenylacetic, α-keto-β-phenylpropionic and α-ketopropionic acids proceeded up to >90% conversion and 2-30% enantiomeric excess. 1:2 complexes of Cr(II) with l-alanine, l-valine, l-aspartic acid, l-histidine and l-phenylalanine were used as reducing agents. The reduction of α-(oximino)phenylacetic acid showed increasing e.e. (and decreasing conversion) with increasing temperature.
- Micskei, Károly,Holczknecht, Orsolya,Hajdu, Csongor,Patonay, Tamás,Marchis, Valér,Meo, Milena,Zucchi, Claudia,Pályi, Gyula
-
p. 143 - 148
(2007/10/03)
-
- Catalytic Leuckart-Wallach-type reductive amination of ketones
-
A Cp*Rh(III) complex catalyzes reductive amination of ketones using HCOONH4 at 50-70°C to give the corresponding primary amines in high yields. The reaction is clean and operationally simple and proceeds at a lower temperature and with higher chemoselectivity than the original Leuckart-Wallach reaction. The new method has been applied to the synthesis of α-amino acids directly from α-keto acids.
- Kitamura, Masato,Lee, Donghyun,Hayashi, Shinnosuke,Tanaka, Shinji,Yoshimura, Masahiro
-
p. 8685 - 8687
(2007/10/03)
-
- A practical asymmetric synthesis of homochiral α-arylglycines
-
Enantioselective reduction of a series of substituted aryl trichloromethyl ketones with the CBS-catecholborane reagent afforded homochiral aryl trichloromethyl carbinols which have been elaborated to give homochiral α-arylglycines in high e.e.
- Mellin-Morliere, Christelle,Aitken, David J.,Bull, Steven D.,Davies, Stephen G.,Husson, Henri-Philippe
-
p. 149 - 155
(2007/10/03)
-
- A facile synthesis of substituted phenylglycines
-
A convenient scaleable process for the preparation of substituted phenylglycines 2 by a modified Strecker reaction is described. Bisulfite- mediated addition of benzylamine and cyanide anion to substituted benzaldehydes 3 gave the aminonitriles 4 which were hydrolysed in two steps to the N-protected amino acid 1. Debenzylation using catalytic transfer hydrogenation gave the title compounds in good yield.
- Davies, Antony J.,Ashwood, Michael S.,Cottrell, Ian F.
-
p. 1095 - 1102
(2007/10/03)
-
- Asymmetric synthesis with chiral hydrogenolysable amines : A new route to enantiomerically pure amino diols
-
Enantiomerically pure amino diols are obtained via diastereoselective reduction of chiral enamino and imino esters (3a), (3b), and (3c).
- Segat, Fabienne,Lingibe, Olivier,Graffe, Bernadette,Sacquet, Marie-Claude,Lhommet, Gerard
-
p. 1451 - 1455
(2007/10/03)
-
- Chemoselective N-deprotection of tert-butyl 2-(trifluoroacetylamino) esters under PTC conditions: Synthesis of tert-butyl 2-aminocarboxylates
-
Trifluoroacetamide 1 is alkylated in good yields (77-83%) by tert-butyl 2-bromocarboxylates 3 under solid-liquid phase transfer catalysis (PTC) conditions [anhydrous K2CO3, triethyl(benzyl)ammonium chloride (TEBA; 10%), MeCN, 80°C]. The resulting tert-butyl 2-(trifluoroacetylamino) carboxylates 5 are chemoselectively hydrolysed in 75-95% yields to the corresponding tert-butyl 2-amino carboxylates, isolated as hydrochlorides 8, under liquid-liquid PTC conditions [CH2Cl2 or Et2O, aqueous 20% KOH, TEBA (10%), 25-40°C].
- Albanese, Domenico,Corcella, Francesco,Landini, Dario,Maia, Angelamaria,Penso, Michele
-
p. 247 - 249
(2007/10/03)
-
- Electrophilic amination of 2-azadienes
-
2-Azadienes 1 bearing a trialkylsilyloxy group on position 3 can be regarded as carboxylic acid synthons. Their cycloadditions with several classes of nitroso compounds have been studied in detail as well as the transformation of the adducts into α-amino acids. The study showed that arylnitroso compounds such as nitrosobenzene reacted with 2-azadienes to give adducts that are potential precursors of α-N-arylamino acids. We have outlined an important limitation to the use of α-chloronitroso compounds. They are not compatible with highly functionalized dienes like 2-azadienes. On the other hand α-cyanonitroso and acylnitroso compounds reacted with azadienes to give adducts which were readily converted into α-amino acid derivatives.
- Gouverneur,Ghosez
-
p. 7585 - 7598
(2007/10/03)
-
- α-Aminonitrile hydration in the presence of hydrogen peroxide in aqueous basic medium
-
α-Aminonitriles are hydrated into α-aminoamides in the presence of hydrogen peroxide in sodic or ammoniacal basic medium. While the hydration mechanism is close to the mechanism described previously in the case of aromatic nitrites, we showed that, in weakly basic conditions, the amine function of α-aminonitrile is competitively oxidized via a peroxyimidic acid by an intramolecular process. In the case of 2-aminopropanenitrile, this reaction leads to pyruvamide oxime. Furthermore, the study of structurereactivity relationships in the hydration of aliphatic and aromatic monofunctional nitriles and α-aminonitriles showed that the reactivity of the substrates towards hydroperoxide onion, which mostly depends on inductive effects of the substituents, is sufficiently enhanced to allow hydration of tertiary α-aminonitriles with low steric hindrance and regioselective hydration of dissymmetric α-aminodinitriles. Eisevier,.
- Taillades, Jacques
-
-
- Reactions of nucleophilic substitution involving solid organic halogen compounds under shear deformation at high pressure
-
Under conditions of shear deformation and high pressures (SD + HP), reactions of nucleophilic substitution were studied: 1) the replacement of aliphatic halogen atom with alkaline metal halides (halo-substituted aliphatic carboxylic acids, 1-bromoadamantane); 2) the replacement of halogen atom in aromatic nucleus (halobenzoic acids, dihalobenzenes) with halogen of salt; 3) the replacement of aliphatic halogen with hydroxyl (hydrolysis in a solid phase); 4) the replacement of halogen with amino group under deformation of the samples of ammonium α-halocarboxylates to give the corresponding amino acids.It was found that the exchange of the halogen atoms bonded with aliphatic carbon is most intensive in the mixtures of alkaline metal iodides with bromo-substituted acetic acid and propionic acids: the exchange reaction in these mixtures is observed even during grinding in the mortar. Unlike the liquid phase, under conditions of SD + HP exchange of the halogen atom of the aromatic nucleus with alkaline metal halides, proceeds successfully, and the reactivity of halides increases in the series Na K Rb Cs.Under SD + HP, 1-Br-adamantane reacts with water to form 1-adamantanol.A high reactivity of the water adsorbed by the reagents is observed. - Key words: shear deformation, high pressure, halogen derivatives of carboxylic acids, dihalobenzenes, alkaline metal halides, ammonium salts of halogen derivatives of carboxylic acids, amino acids, halo-substituted adamantanes, adamantanol, nucleophilic substitution reaction, hydrolysis, ball mill.
- Zharov, A. A.,Chistotina, N. P.,Gaziev, R. G.,Yakovleva, I. I.
-
p. 1050 - 1055
(2007/10/02)
-
- Primordial Amino Acids by Reductive Amination of α-Oxo Acids in Conjunction with the Oxidative Formation of Pyrite
-
The theory of an autotrophic origin of life postulates a primordial formation of amino acids by a mild and specific chemical energy source, namely by the reductive amination of α-oxo acids in conjunction with the oxidative formation of pyrite.Here we show experimental proof for this reaction, which involves carbon dioxide as catalyst.
- Hafenbradi, D.,Keller, M.,Waechtershaeuser, G.,Stetter, K. O.
-
p. 5179 - 5182
(2007/10/02)
-
- Complexation of Amino Acids by Cyclotetrachromotropylene in Aqueous Solution - Importance of CH-? and ?-? Interactions
-
The stability constants K of the 1:1 host to guest complexes formed between the cyclic tetramer, cyclotetrachromotropylene, and amino acids in water at pD 7.0 and 25 deg C were determined by 1H nmr spectroscopy.The results indicate that the interactions between the aromatic ?-bonds of the host and the C-H bonds (for aliphatic amino acids) and aromatic ?-bonds (for aromatic amino acids) of the guests are the major factors responsible for the complexation.There is a linear relationship between log K and the number of C-H bonds interacting with the hydrophobic host cavity.
- Poh, Bo-Long,Tan, Chi Ming
-
p. 3453 - 3462
(2007/10/02)
-
- 3-Oxo- and 3-Imino-4-substituted-1,2,5-thiadiazolidine 1,1-Dioxides: Synthesis, Spectral Properties, and Selected Chemistry
-
A general synthesis for the preparation of 3-oxo- and 3-imino-4-substituted-1,2,5-thiadiazolidine 1,1-dioxides has been developed beginning with an aldehyde, metal cyanide, and sulfamide.The selected chemistry and spectral properties of these compounds are detailed, as well as an X-ray crystallographic structure of a representative member of each class of heterocyclic compound. 3-Imino-4-phenyl-1,2,5-thiadiazolidine 1,1-dioxide crystallizes in space group P212121, with a=5.156 (1) Angstroem, b=7.418 (2) Angstroem, c=24.407 (5) Angstroem, and Z=4.4-(1'-Naphthyl)-3-oxo-1,2,5-thiadiazolidine 1,1-dioxide crystallizes in space group P21/c, with a=19.018 (7) Angstroem, b=5.335 (1) Angstroem, c=11.544 (3) Angstroem, β=103.63 (2) deg, and Z=4.
- Lee, Chai-Ho,Korp, James D.,Kohn, Harold
-
p. 3077 - 3083
(2007/10/02)
-
- Carbon Dioxide. A Reagent for the Protection of Nucleophilic Centers and the Simultaneous Activation for Electrophilic Attack. Part 4. The α-Substitution of (i) Benzyl Alcohol and (ii) Benzylamine
-
Benzyl alcohol is converted into a variety of α-substituted derivatives by a one-pot sequence involving lithiation of an intermediate hemicarbonate ester.Benzylamine is similarly converted by a one-pot sequence to α-substituted benzylamines: here an intermediate carbamate salt is involved.
- Katritzky, Alan R.,Fan, Wei-Qiang,Akutagawa, Kunihiko
-
p. 415 - 418
(2007/10/02)
-
- RACEMIZATION OF PHENYLGLYCINE CATALYZED BY PYRIDOXAL. CATALYTIC EFFECT OF PHOSPHATE ION
-
The racemization reaction of phenylglycine catalyzed by pyridoxal was investigated.The reaction was found to be catalyzed by the phosphate buffer and the detailed kinetic analysis demonstrated that two catalytic terms, kA2-> and KAB2->3-> were implied in the present racemization of phenylglycine.The values of kA and kAB were determined from the dependency of the observed rates on the concentrations of HPO42- and PO43- to be 1.5E-3 s-1 M-1 and 3.1E-1 s-1 M-2, respectively.The latter is the first example of the third order catalytic term in the pyridoxal dependent amino acid racemization.
- Tabushi, Iwao,Kuroda, Yasuhisa,Yamada, Masahiko
-
p. 5695 - 5698
(2007/10/02)
-
- Electron transfer reactions. Reaction of Δ2-oxazoline-5-ones and related substrates with potassium
-
The reaction of several Δ2-oxazolin-5-ones (1a-c, 12) and bioxazolinones (17, 26) with potassium in THF has been investigated.Treatment of 1a with potassium in THF gave a mixture of dibenzamide (11a), N-benzoyl-C-phenylglycine (6a), and C-phenylglycine (10a).A higher yield of 11a was obtained, together with benzoic acid (9), when the reaction of 1a wascarried out in THF saturated with oxygen.The reaction of 1b gave a mixture of β-phenylalanine (10b) and 9, whereas 1c gave a mixture of N-benzoyl-C,C-diphenylglycine (6c) and N-benzoyl-C,C-diphenylmethylamine (5c).Similarly, the reaction of 12 gave a mixture of α-benzamidocinnamic ac id (15) and 9.The reaction of the bioxazolinone 17 with potassium gave a mixture of 11a, 6a, and 10a, along with an appreciable yield of 2,3,5,6-tetraphenylpyrazine (25), whereas 26 under analogous conditions gave a mixture of 15, 6b, and benzamide (29).Reasonable mechanisms, involving the initial formation of radical anion intermediates and their subsequent transformation to give the observed products, have been suggested.Potassium superoxide oxidation of some of these substrates gives similar product mixtures.Cyclic voltammetric studies have been carried out to measure the reduction potentials of 1a-c, 12, 17, and 26 in the generation of their radical anions.The radical anions of these substrates were also generated pulse radiolytically in methanol and their spectra showed absorption maxima in the region 295-350 nm.
- Muneer, Mohammed,Tikare, Ravindra K.,Kamat, Prashant V.,George, Manapurathu V.
-
p. 1624 - 1630
(2007/10/02)
-
- THE SYNTHESIS OF AMINO ACIDS BY REACTION OF AN ELECTROPHILIC GLYCINE CATION EQUIVALENT WITH CARBON NUCLEOPHILES
-
Acetate 1, a glycine cation equivalent, is reacted with organocopper reagents to yield products 2 which can readily be converted to the higher amino acids.This method provides access to aryl-substituted amino acids as well as amino acids containing a β-tertiary carbon.
- O'Donnell, Martin J.,Falmagne, Jean-Bernard
-
p. 699 - 702
(2007/10/02)
-
- The Synthesis of Amino Acids via Organoboranes
-
The reaction of the acetate (1) with organoboranes provides a convenient, new route to amino acids.
- O'Donnell, Martin J.,Falmagne, Jean-Bernard
-
p. 1168 - 1169
(2007/10/02)
-
- STEREOSELECTIVE REDUCTION OF RACEMIC N-HYDROXYAMINO ACIDS BY OPTICALLY ACTIVE THIOLS-IRON(II)
-
Kinetic resolution of racemic N-hydroxyamino acids by the reduction with optically active thiols and a catalytic amount of ferrous ion gave optically active amino acids presumably through enantiodifferentiating coordination of substrates to thiol-Fe(II) complexes.
- Nambu, Yoko,Endo, Takeshi
-
p. 999 - 1002
(2007/10/02)
-
- Anodic Oxidation of Amines. IX. Anodic Oxidation Process of α-Amino Acids in Aqueous Buffer of pH 10
-
Anodic oxidation of α-amino acids with and without a β-hydroxy group was investigated by cyclic voltammetry and controlled potential electrolysis in aqueous carbonate buffer of pH 10.The first wave of the α-amino acids is developed at nearly the same potentials as those observed for the corresponding simple aliphatic amines, showing that a β-hydroxy group does not significantly decrease the first oxidation potential, in contrast to the case of β-alkanolamines.Decarboxylation accompanied by dealkylation is the main reaction process, and a small amount of C-C bond fission also occurs only in the case of the β-hydroxy amino acids.Keywords - α-amino acid; anodic oxidation; decarboxylation; carbon-nitrogen bond fission; carbon-carbon bond fission; aldehyde; N-methyl-α-amino acid; N,N-dimethyl-α-amino acid.
- Masui, Masaichiro,Kamada, Yoshiyuki,Iizuka, Taeko,Ozaki, Shigeko
-
p. 4740 - 4745
(2007/10/02)
-
- Mechanism of the Racemization of Amino Acids. Kinetics of Racemization of Arylglycines
-
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
-
p. 627 - 634
(2007/10/02)
-
- Method for the Racemization of Optically Active Amino Acids
-
A practical method for the racemization of optically active amino acids has been developed.A wide variety of optically active α-amino acids, including neutral amino acids, acidic amino acids, basic amino acids, and imino acids, could be racemized by heating in a medium of acetic acid at 80-100 deg C for 1 h in the presence of 0.05 molar equiv of an aliphatic or an aromatic aldehyde.The factors influencing the racemization were investigated.Phenylglycine, (p-hydroxyphenyl)glycine, and serine could be racemized without complete dissolution of the optically active isomers.Thus, isolation of the racemic modification was easily achieved by simple filtration of the racemic modification suspended in the reaction mixture.The mechanism of the racemization is discussed.
- Yamada, Shigeki,Hongo, Chikara,Yoshioka, Ryuzo,Chibata, Ichiro
-
p. 843 - 846
(2007/10/02)
-
