- 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)
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- 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
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p. 10962 - 10977
(2019/09/03)
-
- One-Pot Enantioselective Synthesis of d-Phenylglycines from Racemic Mandelic Acids, Styrenes, or Biobased l-Phenylalanine via Cascade Biocatalysis
-
Enantiopure d-phenylglycine and its derivatives are an important group of chiral amino acids with broad applications in thepharmaceutical industry. However, the existing synthetic methods for d-phenylglycine mainly rely on toxic cyanide chemistry and multistep processes. To provide green and safe alternatives, we envisaged cascade biocatalysis for the one-pot synthesis of d-phenylglycine from racemic mandelic acid, styrene, and biobased l-phenylalanine, respectively. Recombinant Escherichia coli (LZ110) was engineered to coexpress four enzymes to catalyze a 3-step reaction in one pot, transforming mandelic acid (210 mM) to give enantiopure d-phenylglycine in 29.5 g L?1 (195 mM) with 93% conversion. Using the same whole-cell catalyst, twelve other d-phenylglycine derivatives were also produced from the corresponding mandelic acid derivatives in high conversion (58–94%) and very high ee (93–99%). E. coli (LZ116) expressing seven enzymes was constructed for the transformation of styrene to enantiopure d-phenylglycine in 80% conversion via a one-pot 6-step cascade biotransformation. Twelve substituted d-phenylglycines were also produced from the corresponding styrene derivatives in high conversion (45–90%) and very high ee (92–99%) via the same cascade reactions. A nine-enzymeexpressing E. coli (LZ143) was engineered to transform biobased l-phenylalanine to enantiopure d-phenylglycine in 83% conversion via a one-pot 8-step transformation. Preparative biotransformations were also demonstrated. The high-yielding synthetic methods use cheap and green reagents (ammonia, glucose, and/or oxygen), and E. coli whole-cell catalysts, thus providing green and useful alternative methods for manufacturing d-phenylglycine. (Figure presented.).
- Zhou, Yi,Wu, Shuke,Li, Zhi
-
supporting information
p. 4305 - 4316
(2017/11/21)
-
- 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)
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- 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)
-
- Large α-aminonitrilase activity screening of nitrilase superfamily members: Access to conversion and enantiospecificity by LC-MS
-
A high-throughput screening for the identification of nitrilases demonstrating activity towards alpha-aminonitriles is reported. A LC-MS assay giving access to both conversion and enantiospecificity was developed. 588 candidate enzymes were screened as cell lysates against six alpha-aminonitriles in 96-well microplates. The candidate enzymes were selected following two criteria, their sequence identity with a set of known nitrilases or their phylogenetic position among the nitrilase superfamily. Five enzymes were identified and found to hydrolyse alpha-aminonitrile into the corresponding alpha-aminoacid. The substrate range was found to be very narrow as only two different alpha-aminonitriles, 2-aminovaleronitrile and 2-amino-2- phenylacetonitrile, were found to be substrates. The biocatalytic capabilities of three enzymes were further investigated and the best result was obtained with an enzyme from Burkholderia xenovorans catalysing the enantiospecific hydrolysis of 2-aminovaleronitrile into (S)-norvaline with excellent conversion and enantiomeric excess.
- Bordier, Franck,Stam, Mark,Darii, Ekaterina,Tricot, Sabine,Fossey, Aurelie,Rohault, Johanna,Debard, Adrien,Mariage, Aline,Pellouin, Virginie,Petit, Jean-Louis,Perret, Alain,Vallenet, David,Salanoubat, Marcel,Weissenbach, Jean,Vergne-Vaxelaire, Carine,De Berardinis, Veronique,Zaparucha, Anne
-
-
- 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)
-
- Efficient access to (1H)-isoindolin-1-one-3-carboxylic acid derivatives by orthopalladation and carbonylation of methyl arylglycinate substrates
-
The orthopalladation of methyl arylglycinate derivatives has been studied. The reaction proceeds efficiently for different electron-withdrawing and electron-releasing substituents at the aryl ring. The carbonylation of the orthopalladated complexes affords, in a single step, substituted (1H)-isoindolin-1-one-3-carboxylates. These compounds constitute valuable synthetic intermediates and can be transformed diastereoselectively into octahydroisoindole-1-carboxylic acid derivatives, an important scaffold in the synthesis of many biologically active compounds.
- Nieto, Sonia,Sayago, Francisco J.,Laborda, Pedro,Soler, Tatiana,Cativiela, Carlos,Urriolabeitia, Esteban P.
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experimental part
p. 4185 - 4191
(2011/07/08)
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- Synthesis of new imidazolidin-2,4-dione and 2-thioxoimidazolidin-4-ones via C-phenylglycine derivatives
-
Hydantoins and their derivatives constitute a group of pharmaceutical compounds with anticonvulsant and antiarrhythmic properties, and are also used against diabetes. N-3 and C-5 substituted imidazolidines are examples of such products. As such, we have developed a synthesis of 2,4-dione and 2-thioxo-4-one imidazolidinic derivatives by reaction of amino acids with C-phenylglycine, phenyl isocyanate and phenyl isothiocyanate. Four amino-derivatives IG(1-4) and eight imidazolidinic derivatives, IM(1-8), were obtained in yields of 70-74%. The mass, infrared, 1H and 13C-NMR spectra of representative products are discussed.
- De Sousa Luis, Jose Alixandre,Barbosa Filho, Jose Maria,Lira, Bruno Freitas,Medeiros, Isac Almeida,De Morais, Liana Clebia Soares Lima,Dos Santos, Alexsandro Fernandes,De Oliveira, Cledualdo Soares,De Athayde-Filho, Petronio Filgueiras
-
experimental part
p. 128 - 137
(2010/05/18)
-
- Practical and convenient enzymatic synthesis of enantiopure α-amino acids and amides
-
Catalyzed by the nitrile hydratase and the amidease in Rhodococcus sp. AJ270 cells under very mild conditions, a number of α-aryl- and α-alkyl-substituted DL-glycine nitriles 1 rapidly underwent a highly enantioselective hydrolysis to afford D-(-)-α-amino acid amides 2 and L-(+)-α-amino acids 3 in high yields with excellent enantiomeric excesses in most cases. The overall enantioselectivity of the biotransformations of nitriles originated from the combined effects of a high L-enantioselective amidase and a low enantioselective nitrile hydratase. The influence of the substrates on both reaction efficiency and enantioselectivity was also discussed in terms of steric and electronic effects. Coupled with chemical hydrolysis of D-(-)-α-phenylglycine amide, biotransformation of DL-phenylglycine nitrile was applied in practical scale to produce both D- and L-phenylglycines in high optical purity.
- Wang, Mei-Xiang,Lin, Shuang-Jun
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p. 6542 - 6545
(2007/10/03)
-
- Synthesis of arylglycines by reaction of diethyl N-Boc-iminomalonate with organomagnesium reagents
-
Diethyl N-Boc-iminomalonate (3), prepared on multigram scale, served as a stable and highly reactive electrophilic glycine equivalent which reacted with organomagnesium compounds affording substituted aryl N-Boc-aminomalonates. Subsequent hydrolysis produced arylglycines.
- Calí,Begtrup
-
-
- Highly efficient and enantioselective synthesis of L-arylglycines and D-arylglycine amides from biotransformations of nitriles
-
Under very mild conditions, the Rhodococcus sp. AJ270-catalysed biotransformation of arylglycine nitriles 1, prepared easily from the reaction of substituted benzaldehydes, ammonium chloride and potassium cyanide, proceeded efficiently to produce optically active D-arylglycine amides 2 and L-arylglycines 3 in excellent yields with enantiomeric excesses higher than 99%.
- Wang, Mei-Xiang,Lin, Shuang-Jun
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p. 6925 - 6927
(2007/10/03)
-
- A facile synthesis of substituted phenylglycines
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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.
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p. 1095 - 1102
(2007/10/03)
-
- A simple and efficient diastereoselective Strecker synthesis of optically pure α-arylglycines
-
A simple and economical method for the synthesis of highly functionalised α-amino nitriles, precursors to α-arylglycines with high optical purity is reported. For this purpose, (R) or (S)-2-amino-2- phenylethanol were used as chiral auxiliaries in a 1,3 Strecker reaction. Reactions were studied with a broad range of reagent systems for the generation of cyano nucleophile. Methodology has been extended for the synthesis of (S)-α-(2-iodo-5-nitrophenyl)glycine, (S)-α-(4- methoxyphenyl)glycine and (R)-β-(4-methoxyphenyl)alanine.
- Dave, Rajesh H.,Hosangadi, Bhaskar D.
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p. 11295 - 11308
(2007/10/03)
-
- Efficient chemoenzymatic synthesis of enantiomerically pure α-amino acids
-
A general two-step chemoenzymatic synthesis for enantiomerically pure natural and nonnatural α-amino acids is presented. In the first step of the sequence, the ubiquitous educts aldehyde, amide and carbon monoxide react by palladium-catalyzed amidocarbonylation to afford the racemic N-acyl amino acids in excellent yields. In the second step, enzymatic enantioselective hydrolysis yields the free optically pure a-amino acid and the other enantiomer as the N-acyl derivative, both in optical purities of 85-99.5% ee. The advantage of the chemoenzymatic process compared to other amino acid synthesis are demonstrated by the preparation of various functionalized (-OR, -Cl, -F, -SR) α-amino acids on a 10-g scale.
- Beller, Matthias,Eckert, Markus,Geissler, Holger,Napierski, Bernd,Rebenstock, Heinz-Peter,Holla, E. Wolfgang
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p. 935 - 941
(2007/10/03)
-
- Syntheses of optically active α-amino nitrites by asymmetric transformation of the second kind using a principle of O. Dimroth
-
A mixture of solids As and Bs in equilibrium with the dissolved compounds A1 and B1 is transformed completely into one pure solid, say Bs, if the dissolved compounds A1?B1 are equilibrating in solution. This is applied to transform 1:1 mixtures of solid diastereomeric amygdalates (2-hydroxy-2-phenylacetates; mandelates) (R,R)-3 + (S,R)-3 prepared from racemic α-amino nitriles (R,S)-1 with (R)-mandelic acid 2 into stereochemically pure single diastereomers (R,R)-3, or (S,R)-3 (de > 97%) ('asymmetric transformation of the second kind by application of Dimroth's principle'). Decomposition of the amygdalates (R,R)-3, or (S,R)-3, with aqueous base affords the enantiomerically pure α-amino nitriles (A)-1, or (S)-1 (ten examples). The chiral auxiliary (R)-mandelic acid is recovered almost quantitatively. The optically active α-amino nitriles are hydrolyzed to amides 6, and further to α-N-alkylamino acids 7. N-Benzylamino acids 7 are hydrogenated to α-amino acids 8. Some of the optically active α-amino nitriles 1 are reduced to optically active 1,2-diamines 9. In most cases, absolute configurations could be assigned by comparison of the specific rotations observed with those of authentic compounds.
- Hassan, Nasser A.,Bayer, Erwin,Jochims, Johannes C.
-
p. 3747 - 3757
(2007/10/03)
-
- The reaction between C- and/or N-terminal protected α-aminoacid and sodium hydrogen telluride
-
Sodium hydrogen telluride selectively removed C-terminal alkyl group of C- and/or N-terminal protected α-aminoacids with yields ranging from 70% to 95%.
- Li,Zhou,Ma
-
p. 553 - 559
(2007/10/02)
-
- Synthesis and κ binding affinity of 1-(pyrrolidin-1-ylmethyl)-2-(N-methyl)-4--1,2,3,4-tetrahydroisoquinolin-3(2H)-ones
-
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.
-
p. 515 - 520
(2007/10/02)
-
- Asymmetric Synthesis of α-Amino Acids and α-N-Hydroxyamino Acids from N-Acylbornane-10,2-sultams: 1-Chloro-1-nitrosocyclohexane as a Practical +> Equivalent
-
Successive treatment of N-acylsultams 3 with sodium hexamethyldisilazide, 1-chloro-1-nitrosocyclohexane (1), and aq.HCl gave diastereoisomerically pure, crystalline N-hydroxyamino-acid derivatives 5.These were converted into various amino acids 7, N-hydroxyamino acids 8, and an N-Boc-amino acid 9. (S,S)-Isoleucine (17) and (S,S)-2-acetamido-3-phenylbutyric acid (23) were obtained from N-crotonoylsultam 15 via 1,4-addition of an organomagnesium or organocopper reagent followed by enolate 'amination' with 1.
- Oppolzer, Wolfgang,Tamura, Osamu,Deerberg, Joerg
-
p. 1965 - 1978
(2007/10/02)
-
- Synthesis of Optically Active Arylglycines by Photolysis of Optically Active (β-Hydroxyamino) Carbene-Chromium(0) Complexes
-
Photolysis of chromium complexes having the optically active amino alcohol (1R,2S)-(-)- or (1S,2R)-(+)-2-amino-1,2-diphenylethanol as the amino group produced aryl-substituted oxazinones in good yield with reasonable diastereoselectivity.Facile separation of diastereoisomers followed by mild reductive cleavage produced several arylglycines, having either electron-donating or withdrawing groups on the aromatic ring, in good overall yield and with excellent enantiomeric excess.
- Vernier, Jean-Michel,Hegedus, Louis S.,Miller, David B.
-
p. 6914 - 6920
(2007/10/02)
-
- An Efficient and Practical Synthesis of L-α-Amino Acids Using (R)-Phenylglycinol as a Chiral Auxiliary
-
L-α-Amino acids including L-α-arylglycines were conveniently and stereoselectively synthesized via the α-amino carbonitriles given by the Strecker reaction of (R)-2-amino-2-phenylethanol with aldehydes and hydrogen cyanide.The stereoselectivity of these α-amino carbonitriles was thermodynamically controlled.
- Inaba, Takashi,Kozono, Ichiro,Fujita, Makoto,Ogura, Katsuyuki
-
p. 2359 - 2365
(2007/10/02)
-
- 1-Aryl-N2-alkyl-ethanediamines as isosters of adrenergic arylethanolamines.
-
A family of 1-aryl-N2-alkyl-ethanediamines 1 isosteric with the N-alkyl-arylethanolamines are described. Although the prepared compounds were generally less potent than the N-alkyl-arylethanolamines, the 1-aryl-N'-(phenylmethyl)-N-alkyl-1,2-ethanediamines derivatives 6, are more active than the debenzylated free amino analogs 1, which may be indicative of the importance of the lipophilicity of the substituent at the alpha position to the aromatic ring.
- Berger,Nudelman
-
p. 229 - 233
(2007/10/02)
-
- Asymmetric synthesis of α-amino acids and α-N-hydroxyamino acids via electrophilic amination of bornanesultam-derived enolates with 1-chloro-1-nitrosocyclohexane
-
Successive treatment of N-acylsultams 3 with NaN(TMS)2, 1-chloro-1-nitrosocyclohexane (1) and 1N aq. HCl gave diastereomerically pure, crystalline N-hydroxyamino acid derivatives 4. Products 4 were converted to various amino acids 6, an N-BOC-amino acid 8 and to N-hydroxyamino acids 9. (S,S)-Isoleucine (16) was obtained from N-crotonoylsultam 13 via an organomagnesium-1,4-addition/enolate trapping process generating two stereogenic centers.
- Oppolzer,Tamura
-
p. 991 - 994
(2007/10/02)
-
- THE SYNTHESIS OF AMINO ACIDS BY REACTION OF AN ELECTROPHILIC GLYCINE CATION EQUIVALENT WITH NEUTRAL CARBON NUCLEOPHILES
-
Seven neutral carbon nucleophiles (active aromatics, allylsilanes and a silyl enol ether) were reacted with the glycine cation equivalent 12 in the presence of TiCl4 to yield α-substituted amino acid derivatives in moderate yield (1-61.5 mmolar scale).Deprotection of the Schiff base ester products led to the corresponding amino acids.
- O'Donell, Martin J.,Benett, William D.
-
p. 5389 - 5402
(2007/10/02)
-
- ASYMMETRIC INDUCTIVE SYNTHESIS OF α-AMINOARYLACETIC ACIDS IN CHIRAL MICELLAR SYSTEM
-
In the micellar solution of chiral surfactant N-hexadecyl-N-methylephedrine bromide, seven α-aminoarylacetic acids were synthesized from corresponding aldehydes, the e.e.percent being about 28percent.
- Zhang, Yongmin,Li, Weixing
-
p. 1685 - 1690
(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)
-
- 7-α-Amino-substituted acylamino-3-(1-carboxymethyltetrazol-5-ylthiomethyl)-3-cephem-4-carboxylic acids
-
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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-
- Therapeutic L- and DL- phenylglycines to treat diseases or disorders of reduced blood flow or oxygen availability
-
L- and DL- Phenylglycines of the formula STR1 and pharmaceutically acceptable salts thereof, wherein R is hydrogen or methyl and R1 is NH2, OH or completes a carboxylic ester group, useful in treating certain cardiovascular diseases, diabetes and obesity.
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