- One-pot, two-step synthesis of unnatural α-amino acids involving the exhaustive aerobic oxidation of 1,2-diols
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Herein, we report the nor-AZADO-catalyzed exhaustive aerobic oxidations of 1,2-diols to α-keto acids. Combining oxidation with transamination using dl-2-phenylglycine led to the synthesis of free α-amino acids (AAs) in one pot. This method enables the rapid and flexible preparation of a variety of valuable unnatural AAs, such as fluorescent AAs, photoactivatable AAs, and other functional AAs for bioorthogonal reactions.
- Inada, Haruki,Furukawa, Keisuke,Shibuya, Masatoshi,Yamamoto, Yoshihiko
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supporting information
p. 15105 - 15108
(2019/12/26)
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- Preparative Asymmetric Synthesis of Canonical and Non-canonical α-amino Acids Through Formal Enantioselective Biocatalytic Amination of Carboxylic Acids
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Chemical and biocatalytic synthesis of non-canonical α-amino acids (ncAAs) from renewable feedstocks and using mild reaction conditions has not efficiently been solved. Here, we show the development of a three-step, scalable and modular one-pot biocascade for linear conversion of renewable fatty acids (FAs) into enantiopure l-α-amino acids. In module 1, selective α-hydroxylation of FAs is catalyzed by the P450 peroxygenase P450CLA. By using an automated H2O2 supplementation system, efficient conversion (46 to >99%; TTN>3300) of a broad range of FAs (C6:0 to C16:0) into valuable α-hydroxy acids (α-HAs; >90% α-selective) is shown on preparative scale (up to 2.3 g L?1 isolated product). In module 2, a redox-neutral hydrogen borrowing cascade (alcohol dehydrogenase/amino acid dehydrogenase) allowed further conversion of α-HAs into l-α-AAs (20 to 99%). Enantiopure l-α-AAs (e.e. >99%) including the pharma synthon l-homo-phenylalanine can be obtained at product titers of up to 2.5 g L?1. Based on renewables and excellent atom economy, this biocascade is among the shortest and greenest synthetic routes to structurally diverse and industrially relevant ncAAs. (Figure presented.).
- Dennig, Alexander,Blaschke, Fabio,Gandomkar, Somayyeh,Tassano, Erika,Nidetzky, Bernd
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supporting information
(2019/02/09)
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- Direct Synthesis of Free α-Amino Acids by Telescoping Three-Step Process from 1,2-Diols
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A practical telescoping three-step process for the syntheses of α-amino acids from the corresponding 1,2-diols has been developed. This process enables the direct synthesis of free α-amino acids without any protection/deprotection step. This method was also effective for the preparation of a 15N-labeled α-amino acid. 1,2-Diols bearing α,β-unsaturated ester moieties afforded bicyclic α-amino acids through intramolecular [3 + 2] cycloadditions. A preliminary study suggests that the resultant α-amino acids are resolvable by aminoacylases with almost complete selectivity.
- Inada, Haruki,Shibuya, Masatoshi,Yamamoto, Yoshihiko
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supporting information
p. 709 - 713
(2019/01/25)
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- PRODUCTION METHOD OF α-HYDROXYCARBOXYLIC ACID
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PROBLEM TO BE SOLVED: To provide an efficient production method of an α-hydroxycarboxylic acid in a mild condition, and to provide a production method of a biodegradable plastic from a raw material containing the α-hydroxycarboxylic acid. SOLUTION: In a synthesis method of an α-hydroxycarboxylic acid, which is a production method of the α-hydroxycarboxylic acid by oxidizing a 1,2-diol compound in a reaction system using a nitroxy radical including a skeleton represented by formula(1), water, and an organic solvent, the organic solvent is a compound unmixable with water (R1-R4 are respectively and independently 1-6C hydrocarbon groups). In the synthesis method of the α-hydroxycarboxylic acid, the reaction system has a pH value of 1.0-8.0, and includes a phosphate buffer solution or an acetate buffer solution, and at least one selected from a hypohalite and a halite is added to the reaction system, and further at least one selected from a tetraalkylammonium salt and a fatty acid is added thereto. COPYRIGHT: (C)2016,JPOandINPIT
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Paragraph 0042; 0045; 0063
(2016/10/07)
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- Chemoselective catalytic oxidation of 1,2-diols to α-hydroxy acids controlled by TEMPO-ClO2 charge-transfer complex
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Chemoselective catalytic oxidation from 1,2-diols to α-hydroxy acids in a cat. TEMPO/cat. NaOCl/NaClO2 system has been achieved. The use of a two-phase condition consisting of hydrophobic toluene and water suppresses the concomitant oxidative cleavage. A study of the mechanism suggests that the observed selectivity is derived from the precise solubility control of diols and hydroxy acids as well as the active species of TEMPO. Although the oxoammonium species TEMPO+Cl- is hydrophilic, the active species dissolves into the organic layer by the formation of the charge-transfer (CT) complex TEMPO-ClO2 under the reaction conditions.
- Furukawa, Keisuke,Shibuya, Masatoshi,Yamamoto, Yoshihiko
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supporting information
p. 2282 - 2285
(2015/05/13)
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- Carboxylation with CO2 via brook rearrangement: Preparation of α-hydroxy acid derivatives
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In the presence of CsF, a wide range of α-substituted α-siloxy silanes were carboxylated under a CO2 atmosphere (1 atm) via Brook rearrangement. A variety of α-substituents including aryl, alkenyl, and alkyl groups were tolerated to afford α-hydroxy acids in moderate-to-high yields. One-pot synthesis from aldehydes using PhMe2SiLi and CO 2 was also possible, providing α-hydroxy acids without the isolation of an α-hydroxy silane.
- Mita, Tsuyoshi,Higuchi, Yuki,Sato, Yoshihiro
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- Kinetic resolution of mandelate esters via stereoselective acylation catalyzed by lipase PS-30
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By using lipase PS-30 as catalyst, the kinetic resolution of a series of racemic mandelate esters has been achieved via stereoselective acylation. The value of kinetic enantiomeric ratio (E) reached up to 197.5. Substituent effect is briefly discussed.
- Chen, Peiran,Yang, Wenhong
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supporting information
p. 2290 - 2294
(2014/04/17)
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- Organocatalytic one-pot oxidative cleavage of terminal diols to dehomologated carboxylic acids
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The organocatalytic one-pot oxidative cleavage of terminal 1,2-diols to one-carbon-unit-shorter carboxylic acids is described. The combination of 1-Me-AZADO (cat.), NaOCl (cat.), and NaClO2 caused smooth one-pot oxidative cleavage under mild conditions. A broad range of substrates including carbohydrates and N-protected amino diols were converted without epimerization. Terminal triols and tetraols respectively underwent cleavage of their C-2 and C-3 moieties to afford their corresponding two- and three-carbon-unit-shorter carboxylic acids.
- Shibuya, Masatoshi,Doi, Ryusuke,Shibuta, Takuro,Uesugi, Shun-Ichiro,Iwabuchi, Yoshiharu
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supporting information
p. 5006 - 5009
(2013/01/15)
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- Synthesis of α-hydroxy carboxylic acids via a nickel(II)- Catalyzed hydrogen transfer process
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A new catalytic system for β-alkylation of lactic acid with primary alcohols has been developed. In the presence of nickel(II) acetate tetrahydrate [Ni(OAc)2(H2O)4] and base, lactic acid reacts with primary alcohols to afford the corresponding coupled α-hydroxy carboxylic acids in good to excellent yields via a hydrogen transfer process without any hydrogen acceptor or hydrogen donor. Copyright
- Tang, Guo,Cheng, Chien-Hong
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supporting information; experimental part
p. 1918 - 1922
(2011/10/12)
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- A practical and inexpensive 'convertible' isonitrile for use in multicomponent reactions
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N-tert-Butylamides are readily converted into the corresponding carboxylic acids by simple nitrosation. The process, which occurs under mild nonaqueous conditions, leaves carboxylic esters untouched and transforms multicomponent reaction products into useful building blocks for further synthetic elaboration.
- Le, Hoang V.,Fan, Lijun,Ganem, Bruce
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p. 2209 - 2211
(2011/05/09)
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- Direct asymmetric hydrogenation of 2-oxo-4-arylbut-3-enoic acids
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A challenging direct asymmetric hydrogenation of (E)-2-oxo-4-arylbut-3- enoic acids to give 2-hydroxy-4-arylbutanoic acids (85.4-91.8% ee) was achieved with a Ru catalyst based on SunPhos as the chiral ligand. Further investigation of the reaction revealed that partial isomerization of 2-hydroxy-4-arylbutenoic acids was involved in the hydrogenation process. Employing the reaction conditions to the hydrogenation of 2-oxo-4-phenylbutanoic acid resulted in better enantioselectivity (91.8% ee) and efficiency (TON = 2000, TOF = 200 h-1), which offers a useful method for the synthesis of a common intermediate for ACE inhibitors.
- Zhu, Lvfeng,Meng, Qinghua,Fan, Weizheng,Xie, Xiaomin,Zhang, Zhaoguo
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supporting information; experimental part
p. 6027 - 6030
(2010/11/18)
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- Cyano-phosphorylation of aldehydes catalyzed by a nucleophilic N-heterocyclic carbene
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The first method for cyano-phosphorylation of aldehydes with diethyl cyanophosphonate in the presence of N-heterocyclic carbene prepared from 1,3-bis(2,4,6-trimethylphenyl)imidazolium chloride and KOt-Bu, as a nucleophilic catalyst, is described.
- Fukuda, Yoshimasa,Maeda, Yuka,Kondo, Kazuhiro,Aoyama, Toyohiko
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p. 397 - 398
(2007/10/03)
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- Decomposition of sodium trichloroacetate in the presence of quaternary ammonium under microwave irradiation: A convenient one-pot synthesis of α-hydroxy acids in water
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A good yielding phase-transfer-catalyzed procedure for one-pot preparation of α-hydroxy acids from carbonyl compounds and sodium trichloroacetate by in situ addition and hydrolysis under microwave irradiation is described. Decomposition of sodium trichloroacetate is strongly accelerated by the presence of quaternary ammonium. The reaction can be conducted in water. Copyright Taylor & Francis Group, LLC.
- Yu, Haitao,Fang, Yun,Xia, Yongmei,Wu, Jing
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p. 2421 - 2426
(2007/10/03)
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- Biocatalytic racemization of (hetero)aryl-aliphatic α- hydroxycarboxylic acids by Lactobacillus spp. proceeds via an oxidation-reduction sequence
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The biocatalytic racemization of a range of (hetero)aryl- and (di)aryl-aliphatic α-hydroxycarboxylic acids has been achieved by using whole resting cells of Lactobacillus spp. The essentially mild (physiological) reaction conditions ensure the suppression of undesired side reactions, such as elimination, decomposition or condensation. Cofactor/inhibitor studies using a cell-free extract of Lactobacillus paracasei DSM 20207 reveal that the addition of redox cofactors (NAD+/NADH) leads to a distinct increase in the racemization rate, while strong inhibition is observed in the presence of Thio-NAD+, which suggests that the racemization proceeds by an oxidation-reduction sequence rather than involvement of a "racemase" enzyme. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Nestl, Bettina M.,Glueck, Silvia M.,Hall, Melanie,Kroutil, Wolfgang,Stuermer, Rainer,Hauer, Bernhard,Faber, Kurt
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p. 4573 - 4577
(2007/10/03)
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- METHOD FOR PRODUCING CHIRAL alpha HYDROXYCARBOXYLIC CRYSTALLINE ACIDS
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The invention relates to a method for producing chiral alpha-hydroxycarboxylic crystalline acids consisting in transforming cyanhydrins (R) or (S) into alpha-hydroxycarboxylic acids (R) or (S), respectively by enzymatic hydrolysis in the presence of Rhodococcus erythropolis NCIMB 11540.
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Page/Page column 10-11
(2008/06/13)
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- An inexpensive carbohydrate derivative used as a chiral auxiliary in the synthesis of α-hydroxy carboxylic acids
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Protected α-hydroxy carboxylic acids were synthesized in moderate yield and high diastereoselectivity by alkylation of glycolate (α-hydroxy acetate) enolates using a D-fructose-derived chiral auxiliary. The new chiral center was assigned the R configuration based on comparisons of optical rotations and on one crystal structure analysis. This alkylation methodology is compatible with several hydroxyl protecting groups. The free hydroxy acids were obtained upon removal of the protecting group from the hydroxyl functionality followed by saponification.
- Yu, Hongwu,Ballard, C.Eric,Boyle, Paul D,Wang, Binghe
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p. 7663 - 7679
(2007/10/03)
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- Hydrogenation of α-oxo carboxylic acid derivatives over nickel and palladium catalysts
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Hydrogenation of a number of α-oxo carboxylic acid derivatives over nickel catalysts and palladium black at 20-90°C has been studied. Hydrogenation of sodium 2-oxo-4-phenyl-3-butenoate over nickel catalysts results in reduction of the double bond and keto group to afford sodium 2-hydroxy-4-phenylbutanoate. Hydrogenation of the same substrate over palladium black can be stopped at the stage of formation of sodium 2-oxo-4-phenylbutanoate. Under similar conditions, ethyl 2,2-diethoxy-4-phenyl-3-butenoate shows a low reactivity. Sodium 2-oxo-4-(3-pyridyl)-3-butenoate is hydrogenated over palladium catalysts with formation of sodium 2-hydroxy-4-(3-pyridyl)-3-butenoate, whereas the reaction with analogous furan derivatives is accompanied by cleavage of the furan ring. One-step procedures have been developed for preparation of (9-fluorenyl)hydroxyacetic acid and 1-(9-fluorenyl)-1,2-ethanediol by hydrogenation of (9-fluorenyl)oxo-acetic acid (or its sodium salt) and methyl (9-ffuorenyl)oxoacetate, respectively. 1998 MAHK "Hayka/Interperiodica".
- Slavinskaya,Sile,Korchagova,Katkevich,Lipsbergs,Lukevits
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p. 1750 - 1754
(2007/10/03)
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- New way for the preparation of 4-phenyl-2-oxobutyric acid ethyl ester
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New way for the preparation of 4-phenyl-2-oxobutyric acid ethyl ester 1 has been elaborated. The four-steps synthesis from ethyl pyruvate involves the consecutive condensation of ethyl pyruvate with benzaldehyde, hydrogenation of benzylidenepyruvic acid sodium salt 2a to 4-phenyl-2-hydroxybutyric acid 3 on Ni catalysts, esterification of 3 and oxidation of the ester to 1 with CrO3.
- Siavinska,Sile,Korchagova,Katkevich,Lukevics
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p. 2229 - 2233
(2007/10/03)
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- Ruthenium-catalysed reductive cleavage of allylic esters with formic acid and triethylamine. Application to short-step synthesis of α-hydroxy acids
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Ruthenium-catalysed reductive cleavage reactions of allylic carboxylates and carbonates with formic acid and triethylamine to give olefins were explored.As an application of the ruthenium-catalysed processes, a new synthetic route to α-hydroxy acids has been discovered.The reductive cleavage of allylic esters is considered to proceed through ?-allylruthenium intermediates. Key words: Ruthenium; Catalysis; Reductive cleavage; Allyl; Formic acid
- Maruyama, Yooichiroh,Sezaki, Takao,Tekawa, Masafumi,Sakamoto, Toshiaki,Shimizu, Isao,Yamamoto, Akio
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p. 257 - 264
(2007/10/02)
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- Facile Synthesis of α-Hydroxycarboxylic Acids by Ruthenium-Catalyzed Reduction od Diaalyl α-Oxalylcarboxylates with Formic Acid
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Reaction of diallyl α-oxalylcarboxylates with catalytic amounts of ruthenium complexes gave α-hydroxycarboxylic acids in good yields.
- Shimizu, Isao,Tekawa, Masafumi,Maruyama, Yooichiroh,Yamamoto, Akio
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p. 1365 - 1366
(2007/10/02)
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- 1-Chloroalkyl p-Tolyl Sulfoxides as Useful Agents for Homologation of Carbonyl Compounds: Conversion of Carbonyl Compounds to α-Hydroxy Acids, Esters, and Amides and α,α'-Dihydroxy Ketones
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One-carbon homologation of carbonyl compounds to α-hydroxy acids, esters, and amides by the use of 1-chloroalkyl p-tolyl sulfoxide as a hydroxycarbonyl anion equivalent is reported.Oxidation of the vinyl chlorides, the intermediates of the above-mentioned
- Satoh, Tsuyoshi,Onda, Ken-ichi,Yamakawa, Koji
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p. 4129 - 4134
(2007/10/02)
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- Production of 2-hydroxy substituted arylalkanoic acids and esters by enzymatic hydrolysis
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Enantiomerically pure (2R)-2-hydroxy arylalkanoic acid esters and (2S)-2-hydroxy arylalkanoic acids are prepared by the Pseudomonas lipase-catalyzed selective hydrolyxis of racemic (2RS)-2-hydroxy arylalkanoic acid esters in solution or suspension in an aqueous medium at a controlled pH of from about 5 to about 9.
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- Process for racemization of optically active 4-phenylbutanoic acid esters
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A process for the racemization of optically active 4-phenylbutanoic acid esters which comprises treating optically active 4-phenylbutanoic acid esters of the general formula (1) STR1 wherein R1 represents a hydroxy group, a hydroxy group protected by vinyl ester, or a lower acyloxy group and R2 represents a lower alkyl group with a base selected from the group consisting of alkali metal alcoholates, alkali metal hydrides, and alkali metal amides is provided.
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