- Reductive amination of ketonic compounds catalyzed by Cp*Ir(III) complexes bearing a picolinamidato ligand
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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)
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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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- Enantioselective hydrocyanation of N-protected aldimines
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Enantioselective hydrocyanation of N-benzyloxycarbonyl aldimines catalyzed by a Ru[(S)-phgly]2[(S)-binap]/C6H5OLi system or a bimetallic complex [Li{Ru[(S)-phgly]2[(S)-binap]}]Cl affords the amino nitriles in 92 - 99% ee. The reaction is carried out in tert-C 4H9OCH3 with a substrate-to-catalyst molar ratio in the range of 500 - 5000 at -20 to 0°C. Primary, secondary, and tertiary alkyl imines as well as the aryl and heteroaryl substrates are smoothly cyanated to produce the desired products in high yield.
- Uemura, Masato,Kurono, Nobuhito,Ohkuma, Takeshi
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supporting information; experimental part
p. 882 - 885
(2012/04/05)
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- COMPOSITIONS AND METHODS FOR CYCLOFRUCTANS AS SEPARATION AGENTS
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The present invention relates to derivatized cyclofructan compounds, compositions comprising derivatized cyclofructan compounds, and methods of using compositions comprising derivatized cyclofructan compounds for chromatographic separations of chemical species, including enantiomers. Said compositions may comprise a solid support and/or polymers comprising derivatized cyclofructan compounds.
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Page/Page column 45-49; 61
(2010/12/31)
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- One-pot, regioselective synthesis of substituted arylglycines for kinetic resolution by penicillin G acylase
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Amido-alkylation of electron-rich arenes with phenylacetamide and glyoxylic acid offers an in-expensive route to a large variety of N-phenylacetylated arylglycines that are suited for immediate enzymatic resolution by penicillin G acylase. When performed under mild conditions at 5 °C in acetic acid/HCl, this simple one-pot operation resulted in the formation of single regioisomers only (≥98%). Subsequent kinetic resolution of the amino acid derivatives by penicillin G acylase at pH 8.0 occurred generally with E values >100 and thus furnished free (S)-configurated arylglycines with high enantiomeric purity. The corresponding enantiopure (R)-substrates, easily separable by a phase-selective extraction process, provided the corresponding (R)-enantiomers upon conventional hydrolysis. This one-pot, two-step procedure for arylglycine synthesis, resolution and work-up requires a minimum of equipment and grants rapid access to both enantiopure (S)- and (R)-antipodes of non-natural α-amino acids in small-to large-scale quantities.
- Grundmann, Peter,Fessner, Wolf-Dieter
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experimental part
p. 1729 - 1735
(2009/07/24)
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- Catalytic Leuckart-Wallach-type reductive amination of ketones
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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
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p. 8685 - 8687
(2007/10/03)
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- Synthesis of arylglycines by reaction of diethyl N-Boc-iminomalonate with organomagnesium reagents
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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
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- Peptides with an insulin-like action
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Peptides with an insulin-like action, of formula I: STR1 in which G is a hydrogen atom, an amino add residue, or a monosubstituted or polysubstituted amino acid; D is an amino acid residue, a phosphoamino acid residue, a monosaccharide residue, or a covalent bond; E is --NH--(CH2)n --NR52, a glycerol residue, or --NH--(CH2)p --R6 --R7 ; R1 is (C1 -C4)-alkyl or =O; R2 is a sulfhydryl protecting group, (C1 -C3)-alkyl, or a hydrogen atom; R3 and R4, independently of one another, are a hydrogen atom or methyl; R5, each being identical or different, is a hydrogen atom, 1 to 6 monosaccharide residues, or 1 to 6 monosubstituted or polysubstituted monosaccharide residues; R6 is O PO4 H, PO2 H, NHCOO, S or OCOO; R7 is a hydrogen atom, 1 to 6 monosaccharide residues, or 1 to 6 monosubstituted or polysubstituted monosaccharide residues; w is an integer 1 or 2; their preparation and use for treatment of diabetes mellitus or insulin-independent diabetes.
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- New hydantoinases from thermophilic microorganisms - Synthesis of enantiomerically pure D-amino acids
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A series of 14 D-α-amino acids were prepared in high chemical and optical yields from the corresponding racemic hydantoins by employing two novel hydantoinases from thermophilic microorganisms.
- Keil,Schneider,Rasor
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p. 1257 - 1260
(2007/10/02)
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- An Efficient and Practical Synthesis of L-α-Amino Acids Using (R)-Phenylglycinol as a Chiral Auxiliary
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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
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p. 2359 - 2365
(2007/10/02)
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- Stereoselective synthesis of L-amino acids via Strecker and Ugi reactions on carbohydrate templates
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L-Amino acid derivatives are stereoselectively synthesized in high yield using 2,3,4-tri-O-pivaloyl-α-D-arabinopyranosylamine or 2,3,4-tri-O-pivaloyl-β-L-fucopyranosylamine as the chiral auxiliary in Strecker and Ugi reactions.
- Kunz,Pfrengle,Ruck,Sager
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p. 1039 - 1042
(2007/10/02)
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- THE SYNTHESIS OF AMINO ACIDS BY REACTION OF AN ELECTROPHILIC GLYCINE CATION EQUIVALENT WITH CARBON NUCLEOPHILES
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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
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p. 699 - 702
(2007/10/02)
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- The Synthesis of Amino Acids via Organoboranes
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The reaction of the acetate (1) with organoboranes provides a convenient, new route to amino acids.
- O'Donnell, Martin J.,Falmagne, Jean-Bernard
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p. 1168 - 1169
(2007/10/02)
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- Nonproteinogenic Amino Acids, III. - Syntheses of the Enantiomerically Pure 2-(2-Thienyl)- and 2-(3-Thienyl)glycines. - Molecular Structure of the Intermediate Schiff's Bases
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The syntheses of enantiomerically pure D-(-)- and L-(+)-2-(2-thienyl)- and 2-(3-thienyl)glycines (6a-d) are described.Preparing the amino nitriles 4 directly from 2-thiophenecarbaldehyde (1a) or 3-thiophenecarbaldehyde (1b), respectively, and (4S,5S)-(+)-5-amino-2,2-dimethyl-4-phenyl-1,3-dioxane (2), and hydrocyanic acid (one-step procedure), the aminonitriles 4a and 4b, respectively, are formed in excess.By crystallization they are obtained diastereomerically pure leading to enantiomerically pure D-amino acids 6a and 6b.If, however, the intermediate Schiff's bases 3 are isolated as crystals and then converted with hydrocyanic acid into the respective aminonitriles 4 (two-step procedure), the diastereomeric aminonitriles 4c and 4d, respectively, crystallize resulting in enantiomerically pure L-amino acids 6a and 6d.X-ray structure analyses of the Schiff's bases 3c and 3e revealed the previously postulated E-configuration of the C=N bond and its chiral shielding by the phenyl substituent at C4.
- Weinges, Klaus,Brachmann, Helga,Stahnecker, Peter,Rodewald, Hans,Nixdorf, Matthias,Irngartinger, Hermann
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p. 566 - 578
(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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