- 3-Alkyl-1,2-cyclopentanediones by Negishi cross-coupling of a 3-bromo-1,2-cyclopentanedione silyl enol ether with alkylzinc reagents: An approach to 2-substituted carboxylic acid γ-lactones, homocitric and lycoperdic acids
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Negishi cross-coupling of the silyl-protected 3-bromoenol of 1,2-cyclopentanedione with primary and secondary alkylzinc reagents using Pd-catalysts affords 3-alkyl substituted 1,2-cyclopentanediones in good yield. The method was applied to obtain 3-methyl
- Paju, Anne,Kostomarova, Diana,Matkevit?, Katharina,Laos, Marit,Pehk, T?nis,Kanger, T?nis,Lopp, Margus
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- Synthesis of l-[4-11C]Asparagine by Ring-Opening Nucleophilic 11C-Cyanation Reaction of a Chiral Cyclic Sulfamidate Precursor
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The development of a convenient and rapid method to synthesize radiolabeled, enantiomerically pure amino acids (AAs) as potential positron emission tomography (PET) imaging agents for mapping various biochemical transformations in living organisms remains
- Xu, Youwen,Cankaya, Aylin Sibel,Hoque, Ruma,Lee, So Jeong,Shea, Colleen,Kersting, Lena,Schueller, Michael,Fowler, Joanna S.,Szalda, David,Alexoff, David,Riehl, Barbara,Gleede, Tassilo,Ferrieri, Richard A.,Qu, Wenchao
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supporting information
p. 6848 - 6853
(2018/04/25)
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- μ-Oxo-Dinuclear-Iron(III)-Catalyzed O-Selective Acylation of Aliphatic and Aromatic Amino Alcohols and Transesterification of Tertiary Alcohols
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A highly chemoselective and reactive μ-oxo-dinuclear iron(III) salen catalyst for transesterification was developed. The developed iron complex catalyzed acylation of aliphatic amino alcohols with nearly perfect O-selectivity, even when using activated esters, for which chemoselectivity is more difficult to control. In addition, O-selective transesterification of aromatic amino alcohols was achieved for the first time. The high activity of the iron complex enabled the use of sterically congested tertiary alcohols, including unprecedented tert-butanol.
- Horikawa, Rikiya,Fujimoto, Chika,Yazaki, Ryo,Ohshima, Takashi
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supporting information
p. 12278 - 12281
(2016/08/24)
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- Chemical investigations in the synthesis of O-serinyl aminoribosides
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Glycosylation involving d-ribose derivatives and various N-protected tert-butyl l-serinates can be achieved efficiently by careful choice of the activation method at the anomeric position and of the Lewis acid promoter. The conditions described allow the major formation of the β-anomer required for further elaboration to liposidomycin and caprazamycin analogues.
- Ginisty, Maryon,Gravier-Pelletier, Christine,Le Merrer, Yves
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p. 142 - 150
(2007/10/03)
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- Access to any site-directed isotopomer of methionine, selenomethionine, cysteine, and selenocysteine - Use of simple, efficient modular synthetic reaction schemes for isotope incorporation
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Simple modular reaction schemes that allow access to any isotopomer of protected serine and homoserine have been worked out. These systems could be simply converted into cysteine, selenocysteine, homocysteine, homoselenocysteine, the essential amino acid methionine, and selenomethionine by Mitsunobu chemistry. These sulfur- and selenium-containing amino acids fulfil many essential roles in the living organism. In addition, homoserine could be converted in a few steps into optically active L-vinylglycine. As well as the stable isotopes 13C, 15N, 17O, and 18O, the radioactive isotopes of sulfur, selenium and carbon can also be easily introduced in a site-directed fashion. In view of the wide scope of the Mitsunobu reaction, we feel that many more important systems with the carbon skeleton of serine and homoserine should be preparable through this basic chemistry in any site-directed isotopically labeled form. Wiley-VCH Verlag GmbH & Co, KGaA, 69451 Weinheim, Germany, 2004.
- Siebum, Arjan H. G.,Woo, Wei Sein,Raap, Jan,Lugtenburg, Johan
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p. 2905 - 2913
(2007/10/03)
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- A versatile scaffold for a library of liposidomycins analogues: A crucial and potent glycosylation step
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A key step for the synthesis of a diazepanone scaffold dedicated to a library of MraY inhibitors is described. It involves the O-glycosylation of a conveniently protected L-serine by a D-ribofuranose derivative. High yield and selectivity were obtained.
- Gravier-Pelletier, Christine,Ginisty, Maryon,Le Merrer, Yves
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p. 189 - 193
(2007/10/03)
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- Derivatized Amino Acids Relevant to Native Peptide Synthesis by Chemical Ligation and Acyl Transfer
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Three amino acids were converted into the derivatives 5.2 (from glycine), 6.4a and 6.4b (from alanine), and 8.3a and 8.3b (from O-benzyl serine). These N-alkylated amino acids, which can be deprotected after conversion of the carboxyl into an amide, correspond to the general structure 2.1, a compound class of use in the study of peptide segment coupling by the ligation-acyl transfer method.
- Clive, Derrick L. J.,Hisaindee, Soleiman,Coltart, Don M.
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p. 9247 - 9254
(2007/10/03)
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- Selective nitrolytic deprotection of N-BOC-amines and N-BOC-amino acids derivatives
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The extension of the deprotection procedure using HNO3 in CH2Cl2 to a number of appropriately selected N-BOC-masked amines and derivatives of natural amino acids was investigated. The method was found to work effectively with almost all tested substrates, with the exception of activated aromatic amines and heterocycles which underwent unavoidable faster oxidation. Alanine, phenylalanine, serine and lysine derivatives were efficiently deprotected, as well as dipeptide Ala-Phe, preserving the configuration of the substrates and without affecting copresent Z and ester functions, with a remarkable selectivity towards acid sensitive t-butyl esters. The obtained amino acids esters, isolated and characterized in the form of nitrates salts, proved to be suitable intermediates to be used in peptide synthesis.
- Strazzolini, Paolo,Melloni, Tiziana,Giumanini, Angelo G
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p. 9033 - 9043
(2007/10/03)
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- A novel and efficient route towards α-GalNAc-Ser and α-GalNAc-Thr building blocks for glycopeptide synthesis
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Michael addition of serine and threonine derivatives 4a-4c to 3,4,6-tri- O-benzyl-2-nitro-D-galactal (1) afforded the corresponding 2-deoxy-2-nitro- α-D-galactopyranosides 5a-5c in good yield and stereoselectivity. 2-deoxy-2- nitroglycosides 5a and 5b were reduced to the 2-acetamido compounds by platinized Raney nickel T4. Manipulation of the protecting groups afforded known N-Fmoc-O-(2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-α-D- galactopyranosyl)-L-serine (8a) and -threonine (8b), valuable building blocks for O-glycopeptide synthesis.
- Winterfeld, Gottfried A.,Ito, Yukishige,Ogawa, Tomoya,Schmidt, Richard R.
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p. 1167 - 1171
(2007/10/03)
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- Synthesis of lysophosphatidylserine with 19:4 acyl group, as a novel sodium-potassium ATPase inhibitor, in relation to DLIS-2, an endogenous digoxin-like substance
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A lysophosphatidylserine with 19:4 acyl group proposed as a candidat of DLIS-2, an endogenous digoxin-like substance was chemically synthesized. The synthetic compound showed a significant activity of Na+,K+-ATPase inhibition, which has been accepted as a major indicator activity for the essential hypertension.
- Inami,Teshima,Emura,Shiba
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p. 4033 - 4036
(2007/10/02)
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