- 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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- 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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- Highly selective tripeptide thrombin inhibitors
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Tripeptide aldehydes such as Boc-D-Phe-Pro-Arg-H (5l) exhibit potent direct inhibition of thrombin. This distinction offers important insight for the design of more potent and selective serine protease inhibitors which may be useful pharmacological tools and hold promise for development of clinically useful agents. The structure-activity relationships (SAR) on a series of anticoagulant peptides with high selectivity for the enzyme thrombin are discussed. The SAR is centered on a series of di- and tripeptide arginine aldehydes based on the structure of 5l. The structural and conformational role of the amino acid residue in position 1 was investigated by substitution with conformationally restricted aromatic amino acids, aromatic acids, and a dipeptide isostere containing the ψ[CH2N] amide bond replacement. Many of these peptides demonstrate potent antithrombotic activity along with selectivity toward thrombin, determined by comparison of in vitro inhibitory effects on trypsin, plasmin, factor Xa, and tissue plasminogen activator. Compound 5f, D-1-Tiq-Pro-Arg-H · sulfate is highly active and the most selective tripeptide aldehyde inhibitor of thrombin reported to date.
- Shuman,Rothenberger,Campbell,Smith,Gifford-Moore,Gesellchen
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p. 314 - 319
(2007/10/02)
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- Orally absorbable cephalosporine antibiotics. 1. Structure-activity relationships of benzothienyl- and naphthylglycine derivatives of 7-aminodeacetoxycephalosporanic acid
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A structure-activity relationship study of a number of orally absorbed cephalosporins together with their syntheses is described. These new cephalosporins are benzothienyl- and naphthylglycine derivatives of 7-aminodeacetoxycephalosporanic acid. Several different synthetic methods for the glycine side chains, their protection, and the final acylations are reported. Several of these analogues were more active than cephalexin both in vitro and r538w2 =(R)-7-(3-Benzothienylglycylamido)-3-methyl-3-cephem-4-carb oxylic in vivo against commonly encountered Gram-positive bacteria. (R)7-(3-Benzothienylglycylamido)-3-methyl-3-cephem-4-carboxylic acid has emerged as a potent antibacterial agent and is currently undergoing preclinical evaluation.
- Kukolja,Draheim,Pfeil,et al.
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p. 1886 - 1896
(2007/10/02)
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- Δ3 -3-Vinyl or substituted vinyl-4-carboxy cephalosporins
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The invention is concerned with Δ3 -4-carboxy cephalosporin antibiotics possessing a 3-vinyl or substituted 3-vinyl groups as well as with phosphorous intermediates useful in the preparation thereof.
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- 3-Vinyl-7β-(2,2-disubstituted acetamido)-cephalosporins
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The invention is concerned with Δ3 -4-carboxy cephalosporin antibiotics possessing a 3-vinyl group and having 2,2-disubstituted acetamido group at the 7-position.
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