- Antibiotic N′,N″-dibenzyleremomycin with a reduced 1,2-peptide bond
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Eremomycin derivatives with benzylated amino groups of both residues of eremosamine and with (R) or (S)-2-amino-4-methylpentyl substituted for N-methyl-D-Leu, the first amino acid residue of its heptapeptide, were synthesized in order to study the role of
- Printsevskaya,Olsuf'eva,Lazhko,Preobrazhenskaya
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Read Online
- Synthesis of Enantiomerically Pure 3-Substituted Piperazine-2-acetic Acid Esters as Intermediates for Library Production
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The piperazine heterocycle is broadly exploited in FDA-approved drugs and biologically active compounds, but its chemical diversity is usually limited to ring nitrogen substitutions, leaving the four carbon atoms underutilized. Using an efficient six-step synthesis, chiral amino acids were transformed into 3-substituted piperazine-2-acetic acid esters as diastereomeric mixtures whose cis and trans products (dr 0.56 a? 2.2:1, respectively) could be chromatographically separated. From five amino acids (both antipodes) was obtained a complete matrix of 20 monoprotected chiral 2,3-disubstituted piperazines, each as a single absolute stereoisomer, all but one in multigram quantities. In keeping with our overall purpose of constructing more Csp3-enriched compound libraries for drug discovery, these diverse and versatile piperazines can be functionalized on either nitrogen atom, allowing them to be used as scaffolds for parallel library synthesis and as intermediates for the production of novel piperazine compounds.
- Reddy Guduru, Shiva Krishna,Chamakuri, Srinivas,Raji, Idris O.,MacKenzie, Kevin R.,Santini, Conrad,Young, Damian W.
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p. 11777 - 11793
(2018/09/27)
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- Binding cooperativity between a ligand carbonyl group and a hydrophobic side chain can be enhanced by additional H-bonds in a distance dependent manner: A case study with thrombin inhibitors
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One of the underappreciated non-covalent binding factors, which can significantly affect ligand-protein binding affinity, is the cooperativity between ligand functional groups. Using four different series of thrombin inhibitors, we reveal a strong positiv
- Said, Ahmed M.,Hangauer, David G.
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supporting information
p. 405 - 424
(2015/05/05)
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- Cu(I)-catalyzed synthesis of dihydropyrimidin-4-ones toward the preparation of β- And β3-amino acid analogues
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A copper(I)-catalyzed synthesis of substituted dihydropyrimidin-4-ones from propargyl amides via the formation of ketenimine intermediate has been successfully developed; the synthesis afforded good isolated yields (80-95%). The mild reaction conditions at room temperature allow the reaction to proceed to completion in a few hours without altering the stereochemistry. Further, by involving a variety of reactive nucleophiles, the obtained substituted dihydropyrimidin-4-ones were elegantly transformed into the corresponding β- and β3-amino acid analogues.
- Rajagopal, Basker,Chen, Ying-Yu,Chen, Chun-Chi,Liu, Xuan-Yu,Wang, Huei-Ren,Lin, Po-Chiao
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supporting information
p. 1254 - 1264
(2014/03/21)
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- Synthesis of new (-)-bestatin-based inhibitor libraries reveals a novel binding mode in the S1 pocket of the essential malaria M1 metalloaminopeptidase
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The malarial PfA-M1 metallo-aminopeptidase is considered a putative drug target. The natural product dipeptide mimetic, bestatin, is a potent inhibitor of PfA-M1. Herein we present a new, efficient, and high-yielding protocol for the synthesis of bestatin derivatives from natural and unnatural N-Boc-d-amino acids. A diverse library of bestatin derivatives was synthesized with variants at the side chain of either the α-hydroxyβ-amino acid (P1) or the adjacent naturalα-amino acid (P1′). Surprisingly, we found that extended aromatic side chains at the P1 position resulted in potent inhibition against PfA-M1. To understand these data, we determined the X-ray cocrystal structures of PfA-M1 with two derivatives having either a Tyr(OMe) 15 or Tyr(OBzl) 16 at the P1 position and observed substantial inhibitor-induced rearrangement of the primary loop within the PfA-M1 pocket that interacts with the P1 side chain. Our data provide important insights for the rational design of more potent and selective inhibitors of this enzyme that may eventually lead to new therapies for malaria.
- Velmourougane, Geetha,Harbut, Michael B.,Dalal, Seema,McGowan, Sheena,Oellig, Christine A.,Meinhardt, Nataline,Whisstock, James C.,Klemba, Michael,Greenbaum, Doron C.
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experimental part
p. 1655 - 1666
(2011/05/16)
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- Deglycobleomycin A6 analogues modified in the methylvalerate moiety
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Previous studies have indicated that the methylvalerate subunit of bleomycin (BLM) plays an important role in facilitating DNA cleavage by BLM and deglycoBLM. Eleven methylvalerate analogues have been synthesized and incorporated into deglycoBLM congeners by the use of solid-phase synthesis. The effect of the valerate moiety in the deglycoBLM analogues has been studied by comparison with the parent deglycoBLM A5 using supercoiled DNA relaxation and sequence-selective DNA cleavage assays. All of the deglycoBLM analogues were found to effect the relaxation of the plasmid DNA. Those analogues having aromatic C4-substituents exhibited cleavage efficiency comparable to that of deglycoBLM A5. Some, but not all, of the deglycoBLM analogues were also capable of mediating sequence-selective DNA cleavage.
- Cai, Xiaoqing,Zaleski, Paul A.,Cagir, Ali,Hecht, Sidney M.
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scheme or table
p. 3831 - 3844
(2011/08/02)
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- Preparation of α-hydroxy-β-Fmoc amino acids from N-Boc amino acids
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A general method for the conversion of N-Boc amino acids into their homologated α-hydroxy-β-Fmoc amino acids is described. The protocol involved preparation of the amino aldehyde by reduction of the corresponding Weinreb amides, hydrocyanation, and hydrol
- Johnson, Erik P.,Hubieki, M. Patricia,Combs, Andrew P.,Teleha, Christopher A.
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experimental part
p. 4023 - 4026
(2012/01/12)
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- β-isocupreidine-catalyzed Baylis-Hillman reaction of chiral N-Boc-α-amino aldehydes
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β-Isocupreidine (β-ICD)-catalyzed Baylis-Hillman reaction of chiral N-Boc-α-amino aldehydes and 1,1,1,3,3,3-hexafluoroisopropyl acrylate (HFIPA) takes place without racemization and exhibits the match-mismatch relationship between the substrate and the catalyst. In the case of acyclic amino aldehydes, α,-substrates show excellent syn selectivity and high reactivity in contrast to L-substrates. On the other hand, in the case of cyclic amino aldehydes, D-substrates rather than L-substrates show excellent anti selectivity and high reactivity.
- Nakano, Ayako,Takahashi, Keisuke,Ishihara, Jun,Hatakeyama, Susumi
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p. 5357 - 5360
(2007/10/03)
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- The synthesis of an exhaustively stereodiversified library of cis-1,5 enediols by silyl-tethered ring-closing metathesis.
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[reaction: see text] This report describes the parallel synthesis of all 16 stereoisomers of the cis-1,5 enediol module 1. Compounds 1 derive from 2 by silicon-tethered ring-closing metathesis. Such libraries of stereodiversified ligands provide a unique
- Harrison,Verdine
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p. 2157 - 2159
(2007/10/03)
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- Chiral aminal templates: Diastereoselective addition to hydrazones; an asymmetric synthesis of α-amino aldehydes
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The monohydrazone of glyoxal may be derivatized into a chiral aminal with diamine 7. The resulting chiral reagent 13 reacts with complete diastereocontrol with organolithium reagents in THF. This sterically controlled reaction may be altered to chelation
- Alexakis,Lensen,Tranchier,Mangeney,Feneau-Dupont,Declercq
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p. 1038 - 1050
(2007/10/02)
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- AN EFFICIENT METHOD FOR PREPARATION OF OPTICALLY ACTIVE N-PROTECTED α-AMINO ALDEHYDES FROM N-PROTECTED α-AMINO ALCOHOLS
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N-Protected α-amino aldehydes of high optical purity were prepared in excellent yields from corresponding α-amino alcohols by 1,1,1-tris(acetoxy)-1,1-dihydro-1,2-benzodioxol-3(H)-one (periodinane) oxidation.
- Soucek, Milan,Urban, Jan
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p. 693 - 696
(2007/10/02)
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- A Convenient and Versatile Synthesis of Chiral Aliphatic and Allylic Amines
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Preparation of optically pure aliphatic and allylic amines from amino acids is described.Wittig olefination of α-Boc-amino aldehydes affords Boc-prodected allylic amines which can be deprotected to the corresponding chiral unsaturated amines.Catalytic reduction of the Wittig product prior to deprotection affords aliphatic amines of high optical purity.
- Saari, Walfred S.,Fisher, Thorsten E.
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p. 453 - 454
(2007/10/02)
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- New Methods and Reagents in Organic Synthesis. 67. A General Synthesis of Derivatives of Optically Pure 2-(1-Aminoalkyl)thiazole-4-carboxylic Acids
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Preparations of 2-(1-aminoalkyl)thiazole-4-carboxylic acids (thiazole amino acids), important constituents of a series of cytotoxic cyclic peptides from marine organisms, have been conveniently and efficiently achieved as their N- and C-protected derivatives 6 from N-Boc or N-Z α-amino acids 1 in five steps.Esterification of 1 with methyl iodide followed by reduction with lithium chloride-sodium borohydride afforded N-protected amino alcohols 3.Selective reduction of the α-ester functions of the glutamic acid derivatives (Z-D- and Z-L-Glu(O-t-Bu)-OMe and O-t-Bu) was also achieved under the above reduction conditions.Dimethyl sulfoxide oxidation, followed by condensation with cysteine methyl ester afforded the thiazolidine derivatives 5, which were conveniently dehydrogenated with manganese dioxide, called chemical manganese dioxide (CMD) and produced for batteries, to give the desired thiazole amino acid derivetives 6.The glutamine derivatives (Z-D- and Z-L-(gln)Thz-OMe) were prepared from the corresponding glutamic acid derivatives (Z-D- and Z-L-6f).No appreciable racemization was observed in the above conversion, which was proven by HPLC of the 3,5-dinitrobenzoyl derivatives of thiazole amino acids 6 using a chiral column.
- Hamada, Yasumasa,Shibata, Makoto,Sugiura, Tsuneyuki,Kato, Shinji,Shioiri, Takayuki
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p. 1252 - 1255
(2007/10/02)
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