- Synthesis of new amides based on N-Phthaloyl-α-Amino Acids
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N-phthaloyl derivatives of aliphatic α-amino acids were synthesized using phthalanhydride under standard conditions. The optimization reaction carried out by the thermal method to obtain the amides of these N-phthaloyl amino acids resulted in transimitted rather than amidation. The target amides of N-phthaloyl-α-amino acids were obtained by acylation of the amine with the corresponding acid chloroanhydrides in dichloromethane. These results were compared with the results of a similar acylation in a non-polar solvent (benzene). The dependence of the direction of the reaction on the duration of the acylation and the amount of amine used was established. The conditions for the formation of the corresponding N-phthaloyl-α-amino acid amides and asymmetric phthalic acid diamides were found. It is noteworthy that the formation of diamides is directly proportional to the equivalent amount of amine and the duration of the reaction, which makes it possible to purposefully control the synthesis in one reactor.
- Tukhtaev,Yusupov,Vinogradova
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p. 3049 - 3058
(2021/05/28)
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- General Access to Modified α-Amino Acids by Bioinspired Stereoselective γ-C?H Bond Lactonization
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α-Amino acids represent a valuable class of natural products employed as building blocks in biological and chemical synthesis. Because of the limited number of natural amino acids available, and of their widespread application in proteomics, diagnosis, drug delivery and catalysis, there is an increasing demand for the development of procedures for the preparation of modified analogues. Herein, we show that the use of bioinspired manganese catalysts and H2O2 under mild conditions, provides access to modified α-amino acids via γ-C?H bond lactonization. The system can efficiently target 1°, 2° and 3° γ-C?H bonds of α-substituted and achiral α,α-disubstituted α-amino acids with outstanding site-selectivity, good to excellent diastereoselectivity and (where applicable) enantioselectivity. This methodology may be considered alternative to well-established organometallic procedures.
- Vicens, Laia,Bietti, Massimo,Costas, Miquel
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supporting information
p. 4740 - 4746
(2020/12/25)
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- Chiral sensors for determining the absolute configurations of α-amino acid derivatives
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A simple strategy for configurational assignments of alpha-amino acids has been developed by comparison of the proton NMR chemical shift values of the alpha hydrogens of N-phthaloyl protected alpha-amino acids in the presence of (R)-CSA 1 and (S)-CSA 1, respectively. Highly resolved NMR spectra can be obtained directly on the mixed solution of the chiral solvating agents with N-phthaloyl protected alpha-amino acids in NMR tubes, giving well distinguishable proton signals without interference which dramatically improve the accuracy of assignment and hasten the assigning procedure. The strategy is widely applicable for varied natural and non-natural amino acids.
- Chen, Zhongxiang,Fan, Hongjun,Yang, Shiwei,Bian, Guangling,Song, Ling
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p. 6933 - 6939
(2018/10/02)
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- Chelation-Assisted Palladium-Catalyzed γ-Arylation of Aliphatic Carboxylic Acid Derivatives
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A palladium(II)-catalyzed protocol for the highly regioselective remote γ-C–H arylation of aliphatic carboxylic acid has been disclosed. The 8-aminoquinoline moiety as an intramolecular bidentate chelator was found to be suitable for this γ-C–H arylation. Various aryl iodides successfully produced the regioselectively mono-arylated products with negligible diarylation. Functional group tolerance and easy-to-handle reaction conditions make this method attractive. (Figure presented.).
- Dey, Aniruddha,Pimparkar, Sandeep,Deb, Arghya,Guin, Srimanta,Maiti, Debabrata
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supporting information
p. 1301 - 1307
(2017/04/18)
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- Enantiomerically Pure [2.2]Paracyclophane-4-thiol: A Planar Chiral Sulfur-Based Building Block Readily Available by Resolution with an Amino Acid Chiral Auxiliary
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Acyl chloride of N-phthaloyl-(S)-isoleucine is an efficient chiral auxiliary for the resolution of (±)-[2.2]paracyclophane-4-thiol. A preparative protocol, based on the conversion into diastereoisomeric thiolesters and separation by two fractional crystallizations and column chromatography, was developed. Deprotection with LiAlH4 allowed isolation of the individual thiol enantiomers in good yield (~40%) and high enantiomeric purity (ee >93%). The absolute configurations were determined by comparison of the optical rotation value of the products with literature data and were confirmed by X-ray crystallography.
- Vincent, Adrien,Deschamps, Damien,Martzel, Thomas,Lohier, Jean-Fran?ois,Richards, Christopher J.,Gaumont, Annie-Claude,Perrio, Stéphane
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p. 3961 - 3966
(2016/05/24)
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- Phthaloyl amino acids as anti-inflammatory and immunomodulatory prototypes
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A series of phthalimide analogs were synthesized by derivatization of phthalic anhydride, a highly toxic substance, using a "one pot" condensation reaction to α-amino acids. All phthaloyl amino acid derivatives presented anti-oral inflammatory activity, but compounds 2e and 2g were found to possess the best activities comparable to thalidomide.Most of the compounds effectively suppressed nitric oxide production inmurine cells stimulatedwith lipopolysaccharide. N-phthaloyl amino acids did not exhibit any significant cytotoxicity in vitro when tested against tumor cells as well as a spleen cell culture of BALB/c mice. Compounds 2a, 2g, and 2h were able to inhibit TNF-α and IL-1β production by macrophages. At the same concentration, thalidomide did not exhibit significant inhibitory activity. Springer Science+Business Media 2013.
- Leite, Ana Cristina Lima,Barbosa, Fabio Fernandes,Cardoso, Marcos Verissimo De Oliveira,Moreira, Diogo R. M.,Coelho, Lucas Cunha D.,Da Silva, Elany Barbosa,Filho, Gevanio Bezerra De Oliveira,De Souza, Valdenia Maria Oliveira,Pereira, Valeria Rego A.,Reis, Luiza De C.,Ferreira, Paulo Michel Pinheiro,Pessoa, Claudia,Wanderley, Almir Goncalves,Mota, Fernanda Virginia B.,Da Silva, Teresinha G.
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p. 1701 - 1708
(2014/05/06)
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- Unexpected stereoselective synthesis of (Z)-β-alkenyl substituted β-amino phosphonates through β,γ-dihydrogen shift reaction catalyzed by a copper(I) complex and iodine [Cu(MeCN)4]PF 6/I2
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A series of dialkyl a-diazophosphonates has been prepared from natural amino acids. The diazo decomposition of these diazophosphonate compounds with tetrakis(acetonitrile)copper(I) hexafluorophosphate/iodine, [Cu(MeCN) 4]PF6/I2, as catalyst has been investigated. It was found that the diazo decomposition of dialkyl a-diazophosphonates gave a mixture of β,γ-dihydrogen shift and 1,2-hydride migration products and afforded β-alk- enyl-substituted β-amino phosphonates with the Z configuration. The mechanism of this novel diazo decomposition process was discussed.
- Cai, Yan,Lyu, Hairong,Yu, Chengbin,Miao, Zhiwei
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supporting information
p. 596 - 602
(2014/05/20)
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- Novel phthalimide derivatives with TNF-α and IL-1β expression inhibitory and apoptotic inducing properties
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Modulation of the immune system is an emerging concept in the control of tumor growth. Bearing in mind the pharmacological properties of thalidomide and its phthalimide derivatives, we describe here the structural design, synthesis and pharmacological evaluation of N-acylhydrazones derived from phthalimide. The ability of these N-acylhydrazones in inhibiting the secretion of TNF-α in stimulated cells as well as in inhibiting the transcription of the TNF-α gene was evaluated. We identified N-acylhydrazones 6b and 9c, which substantially impaired TNF-α secretion, expression and reduced IL-1β production similar to thalidomide or Revlimid. N-Acylhydrazone 9c was also able to induce apoptosis in Jurkat cells, however it does not have either antiproliferative properties or cytotoxicity for mouse splenocytes. Beyond that, we have assayed the ability of these compounds to induce cell death and a number of them are able to induce apoptosis.
- Coêlho, Lucas Cunha Duarte,De Oliveira Cardoso, Marcos Veríssimo,Moreira, Diogo Rodrigo Magalh?es,De Moraes Gomes, Paulo André Teixeira,Cavalcanti, Suellen Melo Tibúrcio,Oliveira, Arsenio Rodrigues,De Oliveira Filho, Gevanio Bezerra,Pessoa De Siqueira, Lucianna Rabelo,De Oliveira Barbosa, Miria,De Oliveira Borba, Elizabeth Fernanda,Da Silva, Teresinha Gon?alves,Kaskow, Belinda,Karimi, Mahdad,Abraham, Lawrence J.,Leite, Ana Cristina Lima
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p. 758 - 765
(2014/06/10)
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- Rhodium(II)-catalyzed intramolecular carbonyl ylide formation of α-diazo-β-ketoesters derived from N-phthaloyl-α-amino acids
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Starting from L-alanine, L-phenylalanine, L-leucine, L -norleucine, or L-isoleucine, 2-diazo-3-oxo-4-phthalimido-alkanoates 8 were prepared in three steps. Considerable racemization occurred at the stage of the 3-oxo-4-phthalimido-alkanoates 7. Dirhodium tetraacetate effectively catalyzed the intramolecular formation of carbonyl ylides 9, which in the absence of a trapping reagent underwent a [3+3] cycloaddition reaction to form the dimers 10. Carbonyl ylides 9 underwent [3+2] cycloaddition reactions with several electron-deficient alkenes and alkynes to give oxygen and nitrogen containing multicyclic systems 12-16. The keto group of the αoxy-β-ketoester moiety of cycloadducts 2 and 12 is easily hydrated to give the gem-diol. ARKAT-USA, Inc.
- Enssle, Marc,Buck, Stefan,Werz, Roland,Maas, Gerhard
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p. 149 - 171
(2013/09/24)
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- Diastereoselective synthesis of γ-phthalimido-β-hydroxy esters and n-protected 4-amino-1,3-diols starting from natural α-amino acids
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An efficient diastereoselective synthes.is of γ-phthalimido-β- hydroxy esters and N-protected 4-amino-1,3- diols, starting from natural amino acids is described. The key synthetic strategies involve diastereoselective reduction of γ-phthalimido-β-keto esters with NaBH4 as hydride reducing. The diastereoselective reduction has been found to be highly selective if carried out in methanol at -78°C. Furthermore, the resulting diastereomeric mixture of the reduced products was successfully and cleanly separated by column chromatography.
- Essersi, Amel,Touati, Ridha,Hassine, Bechir Ben
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scheme or table
p. 69 - 72
(2010/08/05)
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- Methyl 2-((succinimidooxy)carbonyl)benzoate (MSB): a new, efficient reagent for N-phthaloylation of amino acid and peptide derivatives.
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A new, efficient, and readily available reagent, methyl 2-((succinimidooxy)carbonyl)benzoate (MSB), for N-phthaloylation of amino acids and amino acid derivatives is described. The phthaloylation procedure is simple and racemization-free and gives excellent results with alpha-amino acids, alpha-amino alcohols, dipeptides, alpha-amino carboxamides, and alpha-amino esters.
- Casimir, J Richard,Guichard, Gilles,Briand, Jean-Paul
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p. 3764 - 3768
(2007/10/03)
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- Flash vacuum pyrolysis of stabilised phosphorus ylides. Part 7. Cyclisation of amino acid derived α-phthalimidoacyl ylides to give pyrroloisoindolediones
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A series of 11 amino acid-derived stabilised ylides 12-14 and 16 have been prepared and characterised. In one case, for compound 17, an X-ray structure determination supports formulation of the compounds as phosphonium enolates. Flash vacuum pyrolysis (FVP) of 12 and 13 at 500°C results in loss of R23PO between the ylide function and one carbonyl of the phthalimido group to give products characterised spectroscopically as the pyrroloisoindolediones 18. The identity of these is also supported by the results of 13C and 15N labelling experiments, but owing to their high reactivity complete separation from the phosphine oxide was not generally possible even when Bu3PO rather than Ph3PO was involved. Chromatographic purification of 29, similarly produced by FVP of 14, led to partial hydrolysis, rearrangement and decarboxylation to give 30. FVP of 12 at 750°C gave the 1-unsubstituted pyrroloisoindolediones 19 in two cases.
- Aitken, R. Alan,Cooper, Harris R.,Mehrotra, Amit P.
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p. 475 - 483
(2007/10/03)
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- Stereoselective Reactions of α-Imide Substituted Radicals
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The Barton esters 17 and 18, synthesized from the corresponding amino acid derivatives 6 and 14, were irradiated in situ with or without an external trap.Thus, thiopyridines 22 and 23, phenylselenides 24 and 25, esters 26 and 27 as well as deuterated products 34 and 35 were isolated when the radicals 20 and 21 were trapped with Barton esters 17 and 18 or with PhSeSePh, methyl acrylate or Bu3SnD.In all cases the anti isomers were isolated as the major products in moderate to excellent selectivity.The stereochemical course of the radical can be explained by the allylic strain model.
- Damm, Wolfgang,Hoffmann, Ursula,Macko, Ludwig,Neuburger, Markus,Zehnder, Margareta,Giese, Bernd
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p. 7029 - 7048
(2007/10/02)
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- Photochemistry of N-Phthaloyl α-Amino Acid Esters: A New Approach to β,γ-Unsaturated α-Amino Acid, Dihydrobenzazepinedione, and Pyrrolizidinone Derivatives
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The N-phthaloyl-α-amino acid methyl esters of 2-aminobutyric acid (2a), valine (2b), norvaline (2c), tert-leucine (2d), isoleucine (2e), allo-isoleucine (2f), leucine (2g), methionine (2h), alanine (2i), and phenylalanine (2k) were synthesized in enantiomerically pure form via the N-phthaloyl-α-amino acids (1a-k), and their photochemistry was studied.Except 2i and 2k, which proved to be photostable, all compounds were converted into three types of products, depending on the substitution pattern: a) isomerization products (derivatives of β,γ-unsaturated α-amino acids) 3a, b, c, and e, b) ring expansion products (benzazepinedione esters) 4a and c, and c) cyclization products (5d from the tert-leucine derivative 2d).High diastereoselectivities (d.r. >95:5) were observed for all reactions except the transformations of the 2-aminobutyric acid derivative 2a.The absolute configuration of the α-stereogenic center was retained during photolysis, as proven for the isodehydrovaline (type a product) 3b.PCC oxidation (to give 7b) and hydrogenation afforded 2b with an optical rotation comparable to the starting material.Treatment of 3b with an acid or a base led to epimerization (3b') or isomerization of the C=C bond (6b), respectively.The diastereomeric dihydrobenzazepinedione esters 4a, b were formed with d.r. = 33:67 (cis:trans) and in 60percent yield during photolysis of 2a.The isoleucine derivative 2e, however, was converted into the cis isomer 4a with high diastereoselectivity (d.r. >95:5), whereas the corresponding allo substrate 2f was only converted into the trans-isomer 4b.Ethylene was extruded during irradiation of the latter substrates and during irradiation of the norvaline derivative 2c, whereas propene extrusion from the leucine derivative 2g led to the formation of the unsubstituted type b product 4c.The methionine derivative 1h was the only N-phthaloylamino acid which did not show photodecarboxylation, instead two ξ-hydrogen abstraction products were formed: the hydroxy acid 9h and the tetracylic lactone 10h.The methionine ester 2h was only converted into the ring expansion products 11h, h' presumably by a photo electron transfer step.The chronology of the double hydrogen transfer reaction (γ- followed by δ-H abstraction, leading to type a products) was determined by using the deuterium labeled compound (+/-)-2b.Key Words: Photochemistry / α-Amino acids / Amino acids, β,γ-unsaturated / Photoisomerization / Benzazepinedione esters / Selectivity, enantio-, diastereo-
- Griesbeck, Axel G.,Mauder, Harald,Mueller, Ingrid
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p. 2467 - 2476
(2007/10/02)
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