Pd/Cu dual catalysis: highly enantioselective access to α-substituted α-amino acids and α-amino amides

2018 ◽  
Vol 54 (6) ◽  
pp. 599-602 ◽  
Author(s):  
Xiaohong Huo ◽  
Jingke Fu ◽  
Xiaobo He ◽  
Jianzhong Chen ◽  
Fang Xie ◽  
...  
Keyword(s):  
Amino Acids ◽  
Catalyst System ◽  
Asymmetric Allylation ◽  
Cu Catalyst ◽  
Dual Catalysis ◽  
High Yields ◽  
Amino Amides

In this work, we have developed a synergistic Pd/Cu catalyst system for the asymmetric allylation of glycine iminoesters/amides, affording a range of α-substituted α-amino acids/amides in high yields and with excellent enantioselectivities (88 → 99% ee).

Canonical interrelationships in morphological characters, yield and nutritional components of corn

2021 ◽  
Vol 8 ◽  
pp. 1-17
Author(s):  
Ivan Carvalho ◽  
José Antonio Gonzalez da Silva ◽  
Murilo Vieira Loro ◽  
Marlon Vinícius Rosa Sarturi ◽  
Danieli Jacoboski Hutra ◽  
...  
Keyword(s):  
Amino Acids ◽  
Bioactive Compounds ◽  
Yield Components ◽  
Zinc Content ◽  
Essential Amino Acids ◽  
Morphological Characters ◽  
Soluble Solids ◽  
World Population ◽  
Canonical Correlations ◽  
High Yields

The increase in the world population, the need to increase food production, both in quantity and quality, becomes increasingly prominent. The objective of this work was to identify the canonical correlations between yield components, morphological characters, micronutrients, bioactive compounds and amino acids in corn. The experimental design used was a randomized block containing 11 treatments arranged in three replications. The treatments consisted of 11 Top Crosses hybrid genotypes, these being made through crosses directed between a narrow genetic base tester hybrid for specific combining ability with 11 S5 inbred lines. It is inferred that groups considered yield components, secondary traits, bioactive compounds, micronutrients and amino acids are dependent. Promising characters are identified for the corn breeding for high yields, nutritional and energetic quality of corn grains. The indirect selection of grains with additions in essential amino acids can be directed to plants with superiority in height, mass and width of grains, phenols, flavonoids, soluble solids and zinc content.

Stereoselective and Site-Specific Allylic Alkylation of Amino Acids and Small Peptides via a Pd/Cu Dual Catalysis

2017 ◽  
Vol 139 (29) ◽  
pp. 9819-9822 ◽  
Author(s):  
Xiaohong Huo ◽  
Rui He ◽  
Jingke Fu ◽  
Jiacheng Zhang ◽  
Guoqiang Yang ◽  
...  
Keyword(s):  
Amino Acids ◽  
Allylic Alkylation ◽  
Small Peptides ◽  
Site Specific ◽  
Dual Catalysis

ChemInform Abstract: A Highly Efficient Cu-Catalyst System for N-Arylation of Azoles in Water.

ChemInform ◽  
2012 ◽  
Vol 43 (40) ◽  
pp. no-no
Author(s):  
Deping Wang ◽  
Fuxing Zhang ◽  
Daizhi Kuang ◽  
Jiangxi Yu ◽  
Junhua Li
Keyword(s):  
Catalyst System ◽  
Highly Efficient ◽  
Cu Catalyst

scholarly journals Synthesis of Imidazol-2-yl Amino Acids by Using Cells from Alkane-Oxidizing Bacteria

2003 ◽  
Vol 69 (3) ◽  
pp. 1670-1679 ◽  
Author(s):  
Annett Mikolasch ◽  
Elke Hammer ◽  
Frieder Schauer
Keyword(s):  
Amino Acids ◽  
Chemical Structure ◽  
Rhodococcus Erythropolis ◽  
Nocardia Asteroides ◽  
Side Chain ◽  
Butanoic Acid ◽  
Transformation Pathway ◽  
Nuclear Magnetic Resonance Spectrometry ◽  
Magnetic Resonance Spectrometry ◽  
High Yields

ABSTRACT Sixty-one strains of alkane-oxidizing bacteria were tested for their ability to oxidize N-(2-hexylamino-4-phenylimidazol-1-yl)-acetamide to imidazol-2-yl amino acids applicable for pharmaceutical purposes. After growth with n-alkane, 15 strains formed different imidazol-2-yl amino acids identified by chemical structure analysis (mass and nuclear magnetic resonance spectrometry). High yields of imidazol-2-yl amino acids were produced by the strains Gordonia rubropertincta SBUG 105, Gordonia terrae SBUG 253, Nocardia asteroides SBUG 175, Rhodococcus erythropolis SBUG 251, and Rhodococcus erythropolis SBUG 254. Biotransformation occurred via oxidation of the alkyl side chain and produced 1-acetylamino-4-phenylimidazol-2-yl-6-aminohexanoic acid and the butanoic acid derivative. In addition, the acetylamino group of these products and of the substrate was transformed to an amino group. The product pattern as well as the transformation pathway of N-(2-hexylamino-4-phenylimidazol-1-yl)-acetamide differed in the various strains used.

scholarly journals Epimerization-free C-term Activation of Peptide Fragments by Ball-Milling

2020 ◽  
Author(s):  
Yves Yeboue ◽  
Marion Jean ◽  
Gilles Subra ◽  
Jean Martinez ◽  
Frédéric Lamaty ◽  
...  
Keyword(s):  
Amino Acids ◽  
Ball Milling ◽  
High Yield ◽  
Coupling Agents ◽  
Peptide Fragment ◽  
Peptide Fragments ◽  
Solution Synthesis ◽  
High Yields ◽  
Synthesis Approach ◽  
Yield And Purity

Ball-milling enabled to perform [2+1], [2+2], and [2+3] peptide couplings with high yields and, if any, very low epimerization. Very good results were obtained with peptide fragments containing highly epimerization-prone and/or highly hindered amino acids at C-term such as phenylglycine, cysteine and valine. Ball-milling was clearly identified as the key element to obtain both high yield and purity along with low epimerization. Indeed, the ball-milling conditions proved to be superior to the classical solution synthesis approach on a various array of widely used coupling agents. These results open avenues for the development of highly efficient, convergent and flexible peptide synthesis strategies based on peptide fragment couplings mediated by ball-milling.

scholarly journals Epimerization-free C-term Activation of Peptide Fragments by Ball-Milling

2020 ◽  
Author(s):  
Yves Yeboue ◽  
Marion Jean ◽  
Gilles Subra ◽  
Jean Martinez ◽  
Frédéric Lamaty ◽  
...  
Keyword(s):  
Amino Acids ◽  
Ball Milling ◽  
High Yield ◽  
Coupling Agents ◽  
Peptide Fragment ◽  
Peptide Fragments ◽  
Solution Synthesis ◽  
High Yields ◽  
Synthesis Approach ◽  
Yield And Purity

Ball-milling enabled to perform [2+1], [2+2], and [2+3] peptide couplings with high yields and, if any, very low epimerization. Very good results were obtained with peptide fragments containing highly epimerization-prone and/or highly hindered amino acids at C-term such as phenylglycine, cysteine and valine. Ball-milling was clearly identified as the key element to obtain both high yield and purity along with low epimerization. Indeed, the ball-milling conditions proved to be superior to the classical solution synthesis approach on a various array of widely used coupling agents. These results open avenues for the development of highly efficient, convergent and flexible peptide synthesis strategies based on peptide fragment couplings mediated by ball-milling.

scholarly journals Isoquinolone Synthesis via Zn(OTf)2-Catalyzed Aerobic Cyclocondensation of 2-(1-Alkynyl)-benzaldehydes with Arylamines

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 683 ◽  
Author(s):  
Dost Muhammad Khan ◽  
Ruimao Hua
Keyword(s):  
Lewis Acid ◽  
Catalyst System ◽  
Oxygen Atmosphere ◽  
High Yields

A zinc(II) triflate-catalyzed cyclocondensation of ortho-alkynylbenzaldehydes with arylamines in the presence of base under an oxygen atmosphere affording isoquinolones in good to high yields has been developed. The advantages of the present catalyst system include the use of an air-stable and cheap commercially available Lewis acid as the catalyst, high atom utilization and easily available starting materials.

scholarly journals Decarbonylation through Aldehydic C–H Bond Cleavage by a Cationic Iridium Catalyst

Synlett ◽  
2019 ◽  
Vol 30 (08) ◽  
pp. 972-976 ◽  
Author(s):  
Tomohiko Shirai ◽  
Kazuki Sugimoto ◽  
Masaya Iwasaki ◽  
Ryuki Sumida ◽  
Harunori Fujita ◽  
...  
Keyword(s):  
Bond Cleavage ◽  
Catalyst System ◽  
Mild Conditions ◽  
Iridium Catalyst ◽  
Reaction Proceeds ◽  
High Yields

We report the decarbonylation of aldehydes through an aldehydic C–H bond cleavage catalyzed by a cationic iridium/bisphosphine catalyst. The reaction proceeds under relatively mild conditions to give the corresponding hydrocarbon products in moderate to high yields. In addition, this cationic iridium catalyst system can be applied to an asymmetric hydroacylation of ketones.

scholarly journals Applications of tert-butanesulfinamide in the asymmetric synthesis of amines

2003 ◽  
Vol 75 (1) ◽  
pp. 39-46 ◽  
Author(s):  
J. A. Ellman
Keyword(s):  
Amino Acids ◽  
Asymmetric Synthesis ◽  
Nucleophilic Addition ◽  
Amino Alcohols ◽  
Wide Range ◽  
Aldehydes And Ketones ◽  
Directing Group ◽  
High Yields ◽  
Direct Condensation

tert-Butanesulfinamide is prepared using catalytic enantioselective methods in two steps from the extremely inexpensive oil waste by-product, tert-butyl disulfide. Direct condensation of tert-butanesulfinamide with aldehydes and ketones provides tert-butanesulfinyl imines in uniformly high yields. The tert-butanesulfinyl group activates the imines for the addition of many different classes of nucleophiles, serves as a powerful chiral directing group, and after nucleophilic addition is readily cleaved by treatment with acid. A wide range of highly enantioenriched amines, including α-branched and α,α-dibranched amines, α- and β-amino acids, 1,2 and 1,3-amino alcohols and α-trifluoromethyl amines are efficiently synthesized using this methodology.

scholarly journals Copper nanoparticles on controlled pore glass (CPG) as highly efficient heterogeneous catalysts for “click reactions”

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Abdolrahim A. Rafi ◽  
Ismail Ibrahem ◽  
Armando Córdova
Keyword(s):  
Copper Nanoparticles ◽  
Heterogeneous Catalysts ◽  
Catalyst System ◽  
Terminal Alkynes ◽  
Click Reactions ◽  
Dipolar Cycloadditions ◽  
Organic Azides ◽  
Controlled Pore Glass ◽  
Pore Glass ◽  
High Yields

AbstractWe herein report that supported copper nanoparticles (CuNPs) on commercially available controlled pore glass (CPG), which exhibit high mechanical, thermal and chemical stability as compared to other silica-based materials, serve as a useful heterogeneous catalyst system for 1,3-dipolar cycloadditions (“click” reactions) between terminal alkynes and organic azides under green chemistry conditions. The supported CuNPs-CPG catalyst exhibited a broad substrate scope and gave the corresponding triazole products in high yields. The CuNPs-CPG catalyst exhibit recyclability and could be reuced multiple times without contaminating the products with Cu.

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