- Iron catalyzed efficient synthesis of poly-functional primary amines via the direct use of ammonia
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An iron catalyzed three-component reaction of alkyl diazoesters, isatins and ammonia is reported. This reaction provided convenient access to non-protected β-hydroxy-α-aminoesters with adjacent quaternary stereocenters. This transformation is achieved via trapping of ammonium ylide which is generated from a diazocompound and ammonia under mild reaction conditions. Poly-functional group unprotected amines are obtained exclusively with up to 77% yield and 62?:?38 dr.
- Ma, Chaoqun,Chen, Jianghui,Xing, Dong,Sheng, Yuan,Hu, Wenhao
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Read Online
- Enantioselective [3 + 2] Annulation of Enals with 2-Aminoacrylates Catalyzed by N-Heterocyclic Carbene
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A novel and convenient strategy for the enantioselective synthesis of γ-lactam derivatives via N-heterocyclic carbene catalyzed formal [3 + 2] annulation of enals with 2-aminoacrylates is disclosed. This activation mode provides a complementary approach to the synthesis of various γ-lactam derivatives in good yields with excellent diastereo- and enantioselectivities. In this process, two consecutive stereocenters are constructed, and a quaternary carbon center is also established.
- Li, Xing-Shuo,Zhao, Liang-Liang,Wang, Xiao-Ke,Cao, Li,Shi, Xiao-Qian,Zhang, Rui,Qi, Jing
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Read Online
- Synthesis of some new 5-arylidene-2,4-thiazolidinedione esters
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Compounds containing the 1,3-thiazolidine-2,4-dione scaffold are gaining increasing scientific interest as potential interventional agents for a variety of disease states. A four-step synthesis of ethyl-(2-(5-arylidine-2,4- dioxothiazolidin-3-yl)acetyl)glycinates, alaninates, butanoates, valinates and norvalinates is described. The synthesis began by converting 1,3-thiazolidine-2,4-dione into its potassium salt, which was treated with ethyl (2-chloroacetamido)glycinates, alaninates, butanoates, valinates and norvalinates, respectively, to obtain the penultimate products. These products were then subjected to a Knoevenagel condensation reaction with different aldehydes to obtain the desired products in low to excellent yields.
- Tshiluka, Ndivhuwo R.,Bvumbi, Mpelegeng V.,Ramaite, Isaiah I.,Mnyakeni-Moleele, Simon S.
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p. 161 - 175
(2021/03/17)
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- Stereospecific Synthesis of 3,4-Dihydro-2 H-naphtho-1,4-oxazin-2-ones by Unification of Benzoxepine-4-carboxylates with Chiral Amino Acid Ethyl Esters
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A novel and efficient stereocontrolled method has been developed for the preparation of chiral 3,4-dihydro-2H-naphtho[1,2-b][1,4]oxazin-2-ones by the reaction of benzoxepine-4-carboxylates with chiral amino acid ethyl esters for the first time. The chiral 3,4-dihydro-2H-naphtho-1,4-oxazinones have been achieved in one step by the formation of C-N, C-C, and C-O bonds.
- Bhimapaka, China Raju,Kasagani, Veera Prasad,Kurma, Siva Hariprasad
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supporting information
p. 2976 - 2983
(2020/03/23)
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- Reductive Alkylation of Amines with Carboxylic Ortho Esters
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We have demonstrated for the first time that carboxylic ortho esters could be used as an alkylating agent in the reductive alkylation of amines. A variety of amines, including amino acid esters, were alkylated affording mono-alkylated products with high selectivity in practical to high yields using standard heterogeneous catalysts. By applying acyclic ortho esters alkylation was completed at room temperature. (Figure presented.).
- Kadyrov, Renat,Moebus, Konrad
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supporting information
p. 3352 - 3357
(2020/07/04)
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- Palladium-Catalyzed Allylic Alkylation of Aldimine Esters with Vinyl-Cyclopropanes to Yield α,α-Disubstituted α-Amino Acid Derivatives
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A synthetically useful approach for the synthesis of functionalized α, α-disubstituted α-amino acid derivatives via palladium-catalyzed 1,7 addition of readily available aldimine esters to vinylcyclopropanes is reported. This methodology was operated under mild conditions, affording α-allylic α-amino esters in good to excellent yields and excellent regio- and stereoselectivity. This transformation displays broad functional-group tolerance and enantioselective allylic alkylation has also been realized using a chiral phosphine ligand to provide the desired product. (Figure presented.).
- Wang, Jiahua,Dai, Zonghao,Xiong, Cheng,Zhu, Jin,Lu, Jinrong,Zhou, Qingfa
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supporting information
p. 5105 - 5111
(2019/11/11)
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- Resveratrol amino acid ester derivative and preparation method thereof
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The invention discloses a resveratrol amino acid ester derivative and a preparation method thereof, and belongs to the technical field of fine chemical substance synthesis. The structure of the resveratrol amino acid ester derivative is represented by a formula shown in the description. The resveratrol amino acid ester derivative is synthesized from resveratrol, R amino acid, R' alcohol, dichlorosulfoxide and di(p-nitrobenzene) carbonate with 4-dimethylaminopyridine (DMAP) as a catalyst and acetonitrile as a solvent, wherein the R amino acid is one of alpha-alanine, beta-alanine and gamma-aminobutyric acid, and the R' alcohol is one of methanol, ethanol and n-propanol. The technical problem that resveratrol is difficult to preserve is solved, the pharmacological toxicity introduced by a resveratrol substituent group is lowered, and the resveratrol amino acid ester derivative has the pharmaceutical effects of resveratrol and amino acid. It is expected that the above novel compound playsa great role in beauty treatment and production of fatigue-relieving and blood pressure-lowering medicines.
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Paragraph 0059; 0066; 0067
(2019/07/04)
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- Synthesis, insecticidal activities and SAR studies of novel anthranilic diamides containing trifluoroethoxyl substituent and chiral amino acid moieties
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Ryanodine receptors (RyRs) activator has become one class of popular insecticide because of its unique mode of action. In order to find more new RyRs activators as insecticidal agents, a series of 18 novel chiral anthranilic diamides were designed by introducing the D-alanine acid and D-serine acid esters as well as trifluoroethoxyl group into the anthranilic diamide skeleton and synthesized successfully based on anthranilic diamide and FKI-1033 structures. The structures of the title compounds Ia–i and IIa–i were confirmed by melting points, 1H NMR, 13C NMR, elemental analysis and specific optical rotation analysis. The preliminary bioassay results indicated that most of the title compounds exhibited considerable larvicidal activities against oriental armyworm at 10 mg/L, especially Ib, Ie and IIh showed remarkable insecticidal activities at 0.5 mg/L. The larvicidal activity against diamondback moth of Ia and IId were 80% and 90% respectively at 0.0001 mg/L, which was similar to that of chlorantraniliprole. The relationship between structure and insecticidal activity was analyzed to reveal a possible co-regulated effect of the chiral amino acid ester, halogen atom or cyano group, and trifluoroethyloxyl group of the skeleton structures of the title compounds, which will provide useful information for guiding the design and discovery of new RyRs activators and insecticidal agrochemicals.
- Zhou, Shaa,Zhou, Sha,Xie, Yongtao,Meng, Xiangde,Wang, Baolei,Xiong, Lixia,Yang, Na,Li, Zhengming
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supporting information
p. 1254 - 1256
(2017/11/24)
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- Site-Selective γ-C(sp3)?H and γ-C(sp2)?H Arylation of Free Amino Esters Promoted by a Catalytic Transient Directing Group
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The first selective PdII-catalysed γ-C(sp3)?H and γ-C(sp2)?H arylation of free amino esters using a commercially available catalytic transient directing group. A variety of free amino esters, including α-amino esters and β-amino esters, amino monoesters and amino bis-esters, are shown to react with a diverse range of simple aryl and heteroaryl iodide reagents.
- Lin, Hua,Wang, Chao,Bannister, Thomas D.,Kamenecka, Theodore M.
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supporting information
p. 9535 - 9541
(2018/07/14)
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- Stereochemistry and conformation of skyllamycin, a non-ribosomally synthesized peptide from streptomyces sp. Acta 2897
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Skyllamycin is a non-ribosomally synthesized cyclic depsipeptide from Streptomyces sp. Acta 2897 that inhibits PDGF-signaling. The peptide scaffold contains an N-terminal cinnamoyl moiety, a β-methylation of aspartic acid, three β-hydroxylated amino acids and one rarely occurring α-hydroxy glycine. With the exception of α-hydroxy glycine, the stereochemistry of the amino acids was assigned by comparison to synthetic reference amino acids applying chiral GC-MS and Marfey-HPLC analysis. The stereochemistry of α-hydroxy glycine, which is unstable under basic and acidic conditions, was determined by conformational analysis, employing a combination of data from NOESY-NMR spectroscopy, simulated annealing and free MD simulations. The simulation procedures were applied for both R- and S-configured α-hydroxy glycine of the skyllamycin structure and compared to the NOESY data. Both methods, simulated annealing and free MD simulations independently support S-configured α-hydroxy glycine thus enabling the assignment of all stereocenters in the structure of skyllamycin and devising the role of two-component flavin dependent monooxygenase (Sky39) as S-selective.
- Schubert, Vivien,Di Meo, Florent,Saaidi, Pierre-Loic,Bartoschek, Stefan,Fiedler, Hans-Peter,Trouillas, Patrick,Suessmuth, Roderich D.
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p. 4948 - 4955
(2014/05/06)
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- Enantioselective synthesis of 1,2,4-triazolines by chiral iron(ii)-complex catalyzed cyclization of α-isocyano esters and azodicarboxylates
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Enantioselective cyclization of α-isocyano esters with azodicarboxylates catalyzed by FeII-N,N′-dioxide complexes has been developed. Under mild conditions, a variety of 1,2,4-triazoline derivatives was obtained in high yields and enantioselectivities.
- Wang, Min,Liu, Xiaohua,He, Peng,Lin, Lili,Feng, Xiaoming
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supporting information
p. 2572 - 2574
(2013/04/10)
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- Peroxisome proliferator-activated receptor-γ mediates the anti-inflammatory effect of 3-hydroxy-4-pyridinecarboxylic acid derivatives: Synthesis and biological evaluation
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Seven 3-hydroxy-4-pyridinecarboxylic acid derivatives (HPs), aza-analogues of salicylic acid and structurally close to other potent inflammatory pyridine compounds such as aminopyridinylmethanols and aminopyridinamines, were synthesized, and their anti-inflammatory activity was evaluated. The synthesis was performed by adopting a general procedure involving an intramolecular Diels-Alder cycloaddition of oxazoles with acrylic acid to form various substituted pyridinic acids. The newly synthesized HPs did not exhibit cytotoxic activity on human monocytes-derived macrophages at concentrations up to 10 2 μM. Anti-inflammatory activity of the compounds was screened in vitro by evaluating the capability to inhibit cytokines release from lipopolysaccharide (LPS) stimulated human macrophages. 3-Hydroxy-1-methyl-4- pyridinecarboxylic acid (24) was found to be the most active HP. At 10 μM concentration, HP 24 reduced LPS-induced and nuclear factor-κB activation and cyclooxygenase-2 expression, while increased intracellular reactive oxygen species generation and peroxisome proliferator-activated receptor (PPAR-γ) mRNA transcript level. Indeed, pre-treatment of LPS-exposed human macrophages with PPAR-γ specific antagonist completely prevented HP 24-induced TNF-α and IL8 down regulation, demonstrating that the PPARγ pathway is mandatory for the HP 24 anti-inflammatory effect. Finally, daily treatment with HP 24 ameliorated the outcome of DSS-induced colitis in mice, significantly reducing colonic MPO activity and IL-1β tissue levels.
- Brun, Paola,Dean, Annalisa,Di Marco, Valerio,Surajit, Pathak,Castagliuolo, Ignazio,Carta, Davide,Ferlin, Maria Grazia
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p. 486 - 497
(2013/06/04)
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- Enantioselective benzoylation of α-amino esters using (S)-1-benzoyl-2-(α-acetoxyethyl)benzimidazole, a chiral benzimidazolide
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(Chemical Equation Presented) A new chiral benzimidazolide is developed as a nonenzymatic acylating agent for enantioselective benzoylation of racemic α-amino esters. The process is highly efficient, which exhibits uniformly high enantioselectivity for α-amino esters with or without aryl substituents under mild reaction conditions. The chiral benzimidazolide is inexpensive and is easily accessible.
- Karnik, Anil V.,Kamath, Suchitra S.
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p. 7435 - 7438
(2008/02/11)
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- Iron porphyrins catalyze the synthesis of non-protected amino acid esters from ammonia and diazoacetates
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Iron complexes of porphyrins (and corroles to a lesser extent) are the first catalysts to utilize ammonia for the synthesis of N-free amino acid esters. The Royal Society of Chemistry 2006.
- Aviv, Iris,Gross, Zeev
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p. 4477 - 4479
(2008/09/19)
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- Mimicking enzymatic transaminations: Attempts to understand and develop a catalytic asymmetric approach to chiral α-amino acids
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Attempts are made to build a bridge between asymmetric catalysis and enzymatic reactions by mechanistic investigations and the development of a catalytic and enantioselective approach to amination of α-keto esters by primary amines catalyzed by chiral Lewis acids as a model for transamination enzymes. Different Lewis acids can catalyze the half-transamination of α-keto esters using primary amine nitrogen sources such as pyridoxamine and 4-picolylamine. The mechanistic studies of the Lewis-acid catalyzed half-transamination using deuterium-labelled compounds show the incorporation of deuterium atoms in several positions of the α-amino acid derivative, indicating that the enol of the α-keto ester plays an important role along the reaction path. The catalytic enantioselective reactions are dependent on the pKa-value of the solvent since enantioselectivities were only obtained in solvents with high pKa-values relative to methanol. However, stronger acidic conditions generally gave better yields, but poor enantioselectivities. A series of chiral Lewis acids were screened as catalysts for the enantioselective half-transamination reactions and moderate yields and enantioselectivities of up to 46% ee were obtained.
- Bachmann, Stephan,Knudsen, Kristian Rahbek,Jorgensen, Karl Anker
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p. 2044 - 2049
(2007/10/03)
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- Catalytic enantioselective transamination of alpha-keto esters: an organic approach to enzymatic reactions.
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The half-transamination reaction of alpha-keto esters with pyridoxamine or 4-picolylamine was found to be catalysed by different metal catalysts in organic solvents giving moderate yields and enantioselectivities of up to 37% ee for methyl-3-indole pyruvate.
- Knudsen, Kristian Rahbek,Bachmann, Stephan,Jorgensen, Karl Anker
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p. 2602 - 2603
(2007/10/03)
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- Small molecules useful in the treatment of inflammatory disease
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Novel compounds of the formula I which are useful for treating or preventing inflammatory and immune cell-mediated diseases. Exemplary compounds are: 5-(R)-(4-bromobenzyl)-3-(3-chloro-5-nitrophenyl)-5-methylimidazoline-2,4-dione; and, 5-(R)-(4-bromobenzyl
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Page column 27
(2010/02/05)
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- 2-(Ethoxycarbonylmethyl)-1H-naphtho[1,8-de]-1,2,3-triazine anion: A new glycine enolate equivalent
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The titled triazine can be alkylated with LDA and a variety of alkyl halides: Subsequent reduction with aluminium amalgam cleaves the naphthotriazine moiety to afford substituted α amino acids in excellent overall yields; the sequence defines a novel methodology that can be applied under non-acidic and largely non-aqueous conditions. (C) 2000 Elsevier Science Ltd.
- Anilkumar,Chandrasekhar,Sridhar
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p. 6665 - 6668
(2007/10/03)
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- N-carboalkoxy-2-nitrobenzenesulfonamides: A practical preparation of N- Boc-, N-Alloc-, and N-Cbz-protected primary amines
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N-Carboalkoxy-2-nitrobenzenesulfonamides, readily prepared by acylation of 2-nitrobenzenesulfonamide (o-NsNH2), can be alkylated by either conventional or Mitsunobu protocols. Since the o-nosyl group can be deprotected under mild conditions, a variety of N-carboalkoxy derivatives of primary amines may be prepared in excellent yields from the corresponding alcohols and/or halides. In addition, allyloxycarbonyl (Alloc), t- butoxycarbonyl (t-Boc), and benzyloxycarbonyl (Cbz) groups can be deprotected in the presence of the o-nosyl group, allowing the resultant N-alkylated 2- nitrobenzenesulfonamides to be used for further preparation of secondary amines.
- Fukuyama, Tohru,Cheung, Mui,Kan, Toshiyuki
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p. 1301 - 1303
(2007/10/03)
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- Synthesis of Tc-D,D-HMPAO and Tc-L,L-HMPAO and their comparison of chemical and biological properties
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Tc-D,D- and Tc-L,L-HMPAO were synthesized. The stability of Tc-D,D- and Tc-L,L-HMPAO in vitro is similar to that of d,l-isomers by the spectrophotometric and three strips methods. Cerebral uptake (%D in brain) for the L,L-isomer is higher than the D,D- and d,l-isomer in rats. Delayed studies shows that Tc-L,L-HMPAO reveals less washout and reflects a higher cerebral deposition properties than the D,D- and d,l-isomer.
- Ding, Hueisch-Jy,Huang, Ying-Fong,Tzeng, Cherng-Chyi,Wei, Li-Mei,Yeh, Si-Jung
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p. 3199 - 3202
(2007/10/03)
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- (3R)- AND (3S)-METHYLPIPERAZINE-2,5-DIONE DERIVATIVES AS USEFUL INTERMEDIATES IN THE ENANTIOSELECTIVE SYNTHESIS OF α-AMINO ESTERS
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Treatment of (3S)-3-methylpiperazine-2,5-dione 1 with lithium hexamethyldisilazide (LHMDS) followed by alkylation with several alkyl bromides affords (3S,6S)-3-methyl-6-alkyl derivatives 3 (a-e) in d.e. greater than 98percent.The same reaction sequence carried out on the (3R)-derivative 2 leads to a diastereoisomeric mixture of (3R,6S)-4 (a-e) and (3R,6R)-5 (a-e), the ratio 5 : 4 depending on the alkylating reagent.The configuration at C-6 (of 3, 4 and 5) has been assigned on the basis of 1H-NMR spectroscopic data and conformational analysis performed by the MMPMI program.Cleavage of the heterocyclic ring of 3 (b, d) and 5 (b, d) leads to the corresponding (S)- and (R)-α-amino esters respectively.
- Orena, Mario,Porzi, Gianni,Sandri, Sergio
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p. 2125 - 2152
(2007/10/02)
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- Reduction of azides to amines with borohydride exchange resin - Nickel acetate
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Borohydride exchange resin (BER) - nickel acetate system in methanol readily reduces both aliphatic and aromatic azides to the corresponding amines in excellent yields.
- Yoon,Choi,Shon
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p. 3047 - 3053
(2007/10/02)
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- A New Chiral Glycine Synthon. Synthesis, X-Ray Structure of (-)-(2S,4R)-2-Ethoxycarbonyl-4-phenyl-1,3-oxazolidine and Diastereoselective Nucleophilic Ring Opening to (R)-Ethyl α-Amino Carboxylates.
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Condensation of (R)-N-benzyl-2-phenylglycinol 1 with the methyl hemiacetal of ethyl glyoxylate leads to (2S,4R)-2-ethoxycarbonyl-4-phenyl-1,3-oxazolidine 2 as the major product, obtained as a pure enantiomer after column chromatography.Compound 2 is stereoselectively cleaved by dialkylzinc reagents, prepared from alkylmagnesium iodides and ZnCl2, with moderate to good d.e. (72-94 percent).These compounds, after separation by column chromatography and debenzylation by hydrogenolysis in the presence of 10percent Pd on carbon, lead to enantiomerically pure ethyl α-amino carboxylates with good chemical yields. Key words: Chiral Oxazolidines, alpha-amino Esters, Chiral Glycine Synthon, Ring Opening, Asymmetric Synthesis
- Andres, Celia,Gonzalez, Alfonso,Pedrosa, Rafael,Perez-Encabo,Garcia-Granda, Santiago,et al.
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p. 4743 - 4746
(2007/10/02)
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- Preferential Formation of Amino Acid Esters in Aqueous Alcohol Solutions: Solvolysis of 6,6'-Bis(aminoacylamino)-2,2'-bipyridine by Metal Coordination
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Exclusive formation of amino acid esters took place at an appreciable rate in the CuII-catalysed solvolysis of 6,6'-(α-alanylamino or α-phenylalanylamino)-2,2'-bipyridine in alcohol-borate buffer (pH 7.2) solutions at 20 deg C via formation of an amide-O-coordinated complex, even though appreciable amounts of water (0-40percent v/v) were present in the solution.
- Araki, Koji,Kuboki, Takashi,Yamada, Masaki,Shiraishi, Shinsaku
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p. 1060 - 1062
(2007/10/02)
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- ENANTIOSELECTIVE HYDROLYSIS BY BAKER'S YEAST - II. ESTERS OF N-ACETYL AMINO ACIDS
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D-N-Acetyl amino acid esters were obtained via enantioselective hydrolysis of their racemates by use of fermenting yeast.Evidence is given that proteinases are the enzymes involved.
- Glaenzer, B. I.,Faber, K.,Griengl, H.
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p. 771 - 778
(2007/10/02)
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- EFFET DE LA CONCENTRATION EN ACIDE FLUORHYDRIQUES DANS LA PYRIDINE SUR LA REGIO-SELECTITE DE LA FLUORATION PAR DEAMINATION D'α-AMINO-ESTERS : SYNTHESES DE COMPOSES CARBOXYLES-β-FLUORES.
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Fluorodeamination of α-amino-esters with sodium nitrite in HF-pyridine gives mainly β-fluoro-esters.The molar ratio HF-pyridine is the main parameter for the α-β regioselectivity.
- Hamman, Sylvain,Beguin, Claude G.
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- Reaction of 4-Chloro-3-nitrocoumarin with Glycine and Alanine, and the Synthesis of 1-Benzopyranopyrimidine-3,5-dione
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A considerable improvement of the yields obtained in substitution of halogens in 4-chloro-3-nitrocoumarin by amino acid or amino acid ester residues was achieved over literature claims.Electrochemical reduction of the nitro group in these products brought about a ring closure leading to benzopyranopyrimidinones, which are obtained in excellent yields.
- Stunic', Z.,Trkovnik, M.,Lac'an, M.,Jankovic',R.
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p. 511 - 513
(2007/10/02)
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