- Synthesis of Unnatural α-Amino Acid Derivatives via Light-Mediated Radical Decarboxylative Processes
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Unnatural amino acids (UAAs) are key building blocks with widespread application across several scientific fields. Therefore, it is highly attractive to develop straightforward and simple methodologies capable of granting quick access to these species. Herein we report a light-mediated protocol for the synthesis of UAA via radical decarboxylative processes. This methodology, which employs readily available and abundant starting materials – such as carboxylic and α-keto acids – proceeds under very mild reaction conditions and shows a high functional group tolerance. In addition, the products of the radical reaction can be readily derivatized to grant rapid access to complex UAAs. (Figure presented.).
- Merkens, Kay,Aguilar Troyano, Francisco José,Djossou, Jonas,Gómez-Suárez, Adrián
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supporting information
p. 2354 - 2359
(2020/05/06)
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- Synthetic method of L-high phenylalanine
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The invention relates to a synthetic method of L-high phenylalanine, and belongs to the technical field of compound synthesis. The synthetic method comprises the following steps: (1) dehydrating: making raw materials react with phosphorus trichloride to be made into L--aspartic anhydride hydrochloride; (2) carrying out acylation: taking sulfonated graphene as a catalyst, and performing a Friedel-Crafts reaction with benzene; (3) carrying out reduction: carrying out a hydrogenation reaction on carbonyl groups under the catalysis of palladium-carbon to obtain L-high phenylalanine hydrochloride; (4) performing neutralization: using alkaline water to neutralize hydrochloride, carrying out cooling crystallization and centrifugal filtration to obtain the product, namely L-high phenylalanine. The L-high phenylalanine disclosed by the invention is greatly reduced in catalyst amount, is 0.5 to 20% of the mass of a substrate, and further easy to separate and high in purity of an acylated product and further reduces influence on a subsequent carbonyl reduction reaction, the purity of the final product (HPLC) reaches up to more than 99.5%, and the overall yield can reach more than 90%, so that the L-high phenylalanine has good industrial production prospects.
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Paragraph 0026; 0029-0030; 0035; 0036; 0037; 0038-0102
(2017/07/20)
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- A highly diastereoselective decarboxylative mannich reaction of β-keto acids with optically active N-sulfinyl α-imino esters
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A range of protected γ-oxo-α-amino esters have been prepared in a highly regio- and stereoselective manner through the decarboxylative Mannich reaction of β-keto acids with optically active N-tert-butanesulfinyl α-imino esters in the presence of 3 mol % La(OTf)3 or 5 mol % Y(OTf)3 at 20 °C. Preliminary mechanistic studies indicate that the reaction proceeds through imine addition followed by decarboxylation.
- Yang, Cui-Feng,Shen, Chen,Wang, Jian-Yong,Tian, Shi-Kai
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supporting information; experimental part
p. 3092 - 3095
(2012/08/28)
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- Synthesis of novel chiral oxazoline ligands and application in the highly enantioselective diethylzinc addition to N-diphenylphosphinoylimines
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Two sets of novel chiral oxazoline ligands were designed and conveniently prepared from readily available l-aspartic acid and evaluated in enantioselective diethylzinc addition to N-diphenylphosphinoyl imines. In the presence of stoichiometric amounts of these ligands, high enantioselectivities (up to 95% ee) and yields (up to 85%) were achieved for several aromatic imines in toluene at room temperature. Furthermore, the effect of the structure of the ligand on the reaction was studied.
- Yan, Gexin,Wu, Yong,Lin, Wenqing,Zhang, Xiaomei
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p. 2643 - 2648
(2008/04/05)
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- Highly functionalised organolithium and organoboron reagents for the preparation of enantiomerically pure α-amino acids
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Homochiral, highly functionalised organolithium reagents derived from l-serine have been generated and reacted with electrophiles. The novel enantiomerically pure adducts thus obtained were then converted, through β-amino alcohols, into novel non-proteinogenic α-amino acids. The methodology also made available a novel boronic acid which was then employed as a Suzuki cross-coupling partner, elaborating a new pathway to phenylalanine analogues.
- Barfoot, Christopher W.,Harvey, Joanne E.,Kenworthy, Martin N.,Kilburn, John Paul,Ahmed, Mahmood,Taylor, Richard J.K.
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p. 3403 - 3417
(2007/10/03)
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- Highly Functionalized Organolithium Reagents for Enantiomerically Pure α-Amino Acid Synthesis
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(Equation presented) Highly functionalized L-serine-derived organolithium reagents have been generated and reacted with a variety of electrophiles, delivering novel enantiomerically pure adducts. These adducts were then converted into homochiral amino alcohols and novel nonproteinogenic α-amino acids, including an aspartic acid mimic that has been synthesized in an enantiomerically pure form for the first time.
- Kenworthy, Martin N.,Kilburn, John Paul,Taylor, Richard J. K.
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- Catalytic, enantioselective alkylation of α-imino esters: The synthesis of nonnatural α-amino acid derivatives
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Methodology for the practical synthesis of nonnatural amino acids has been developed through the catalytic, asymmetric alkylation of α-imino esters and N1O-acetals by enol silanes, ketene acetals, alkenes, and allylsilanes using chiral transiti
- Ferraris,Young,Cox,Dudding,Drury III,Ryzhkov,Taggi,Lectka
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- 2-AMINO-4-PHENYL-4-OXO-BUTYRIC ACID DERIVATIVES
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Use in the prevention and/or in the treatment of neurodegenerative diseases of 2-amino-4-phenyl-4-oxo-butyric acid derivatives which act as kynureninase enzyme inhibitors and/or kynurenine-3-hydroxylase enzyme inhibitors. Several of these derivatives are new and, as such, constitute a further object of this invention, together with the process for their preparation and the pharmaceutical compositions containing them.
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- Amino Acid Anhydride Hydrochlorides as Acylating Agents in Friedel-Crafts Reaction: A Practical Synthesis of L-Homophenylalanine
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The use of amino acid hydrochlorides as acylating agents in Friedel-Crafts reaction is presented for the first time. A practical and convenient route to L-homophenylalanine from L-aspartic acid in 3 steps in 80 percent overall yield with >99 percent ee is thus achieved.
- Lin, Wenqing,He, Ze,Zhang, Haile,Zhang, Xiaomei,Mi, Aiqiao,Jiang, Yaozhong
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p. 1007 - 1009
(2007/10/03)
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- Catalytic, enantioselective alkylations of N,O- and N,N-acetals and hemiacetals
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We report the first examples of catalytic, enantioselective alkylation of N,O-acetals to produce useful amino acid derivatives 5 in high yield (73- 93%) and enantioselectivity (70-96%). We have extended the utility of our reaction to include a simple one-pot procedure from readily available starting materials. We also provide several different N-based protecting groups that greatly increase the flexibility of the reaction. In addition, we have elucidated novel mechanistic information including the discovery of unique transilylations that start off the catalytic reactions of enol silane nucleophiles with N,O-acetals. These details will guide us in further explorations of the reaction's scope and utility.
- Ferraris, Dana,Young, Brandon,Dudding, Travis,Drury III, William J.,Lectka, Thomas
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p. 8869 - 8882
(2007/10/03)
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- Synthesis of α-Amino Acids by Reaction of t-Butyl N-(t-Butoxycarbonyl)iminoacetate With C-Nucleophiles
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The reaction of t-butyl N-(t-butoxycarbonyl)iminoacetate with Grignard reagents or enamines yields N-(t-butoxycarbonyl)amino acid t-butyl esters which can be easily converted into the free amino acids by treatment with acids.
- Muenster, Peter,Steglich, Wolfgang
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p. 223 - 225
(2007/10/02)
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