- Chemo- and Diastereoselective N-Heterocyclic Carbene-Catalyzed Cross-Benzoin Reactions Using N-Boc-α-amino Aldehydes
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N-Boc-α-amino aldehydes are shown to be excellent partners in cross-benzoin reactions with aliphatic or heteroaromatic aldehydes. The chemoselectivity of the reaction and the facial selectivity on the amino aldehyde allow cross-benzoin products to be obtained in good yields and good diastereomeric ratios. The developed method is utilized as the key step in a concise total synthesis of d-arabino-phytosphingosine.
- Haghshenas, Pouyan,Gravel, Michel
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- Fluorinated Olefinic Lactams: The Case of Amino Acids - Preparation and Mechanistic Studies
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Herein, we report the synthesis of analogues of amino acids with a monofluorovinyl moiety. Interestingly, we have found that cyclization of the obtained products proceeds easily in all cases. The cyclization process has not previously been observed at this reaction stage, and such fluorinated lactams derived from phenylalanine, valine, alanine have not been described before.
- Bartoszak-Adamska, El?bieta,Go?dyn, Mateusz,Koroniak, Henryk,Koroniak-Szejn, Katarzyna,Salamon-Krokosz, Katarzyna,Siod?a, Tomasz
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- Efficient Entropy-Driven Inhibition of Dipeptidyl Peptidase III by Hydroxyethylene Transition-State Peptidomimetics
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Dipeptidyl peptidase III (DPP3) is a ubiquitously expressed Zn-dependent protease, which plays an important role in regulating endogenous peptide hormones, such as enkephalins or angiotensins. In previous biophysical studies, it could be shown that substr
- Ivkovic, Jakov,Jha, Shalinee,Lembacher-Fadum, Christian,Puschnig, Johannes,Kumar, Prashant,Reithofer, Viktoria,Gruber, Karl,Macheroux, Peter,Breinbauer, Rolf
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supporting information
p. 14108 - 14120
(2021/09/09)
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- A rapid and efficient one-pot method for the reduction of N-protected α-amino acids to chiral α-amino aldehydes using CDI/DIBAL-H
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N-Protected amino acids can be easily converted into chiral α-amino aldehydes in a one-pot reaction by activation with CDI followed by reduction with DIBAL-H. This method delivers Boc-, Cbz- and Fmoc-protected amino aldehydes from proteinogenic amino acids in very good isolated yields and complete stereointegrity.
- Ivkovic, Jakov,Lembacher-Fadum, Christian,Breinbauer, Rolf
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p. 10456 - 10460
(2015/11/10)
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- Synthesis of proline analogues as potent and selective cathepsin S inhibitors
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Cathepsin S is a potential target of autoimmune disease. A series of proline derived compounds were synthesized and evaluated as cathepsin S inhibitors. We discovered potent cathepsin S inhibitors through structure-activity relationship studies of proline analogues. In particular, compound 19-(S) showed promising in vitro/vivo pharmacological activities and properties as a selective cathepsin S inhibitor.
- Kim, Mira,Jeon, Jiyoung,Song, Jiyeon,Suh, Kwee Hyun,Kim, Young Hoon,Min, Kyung Hoon,Lee, Kwang-Ok
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p. 3140 - 3144
(2013/06/26)
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- A palladium iodide-catalyzed carbonylative approach to functionalized pyrrole derivatives
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A novel and convenient approach to functionalized pyrroles is presented, based on Pd-catalyzed oxidative heterocyclization-alkoxycarbonylation of readily available N-Boc-1-amino-3-yn-2-ols. Reactions were carried out in alcoholic solvents at 80-100 °C and under 20 atm (at 25 °C) of a 4:1 mixture of CO-air, in the presence of the PdI2-KI catalytic system (2-5 mol % of PdI2, KI/PdI2 molar ratio = 10). In the case of N-Boc-1-amino-3-yn-2-ols 3, bearing alkyl or aryl substituents, the carbonylation reaction led to a mixture of Boc-protected and N-unsubstituted pyrrole-3-carboxylic esters 4 and 5, respectively. This mixture could be conveniently and quantitatively converted into deprotected pyrrole-3-carboxylic esters 5 by a simple basic treatment. In the case of diastereomeric (3RS,4RS)- and (3RS,4SR)-N-Boc-3-amino-2-methyldec-5-yn-4-ol (syn-3f and anti-3f, respectively, whose relative configuration was determined by X-ray crystallographic analysis), no particular difference was observed in the reactivity of the two diastereomers between them and with respect to the diastereomeric mixture (3S,4S) + (3S,4R). Interestingly, N-Boc-2-alkynyl-1- amino-3-yn-2-ols 6, bearing an additional alkynyl substituent α to the hydroxyl group, spontaneously underwent N-deprotection under the reaction conditions and regioselective water addition to the alkynyl group at C-3 of the corresponding pyrrole-3-carboxylic ester derivative, thus directly affording highly functionalized pyrrole derivatives 7 in one step. In a similar manner, a novel functionalized dihydropyrrolizine derivative 9 was directly synthesized starting from (S)-7-(pyrrolidin-2-yl)trideca-5,8-diyn-7-ol 8.
- Gabriele, Bartolo,Veltri, Lucia,Mancuso, Raffaella,Salerno, Giuseppe,Maggi, Sabino,Aresta, Brunella Maria
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experimental part
p. 4005 - 4016
(2012/06/18)
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- Development and comparison of the substrate scope of Pd-catalysts for the aerobic oxidation of alcohols
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(Chemical Equation Presented) Three catalysts for aerobic oxidation of alcohols are discussed and the effectiveness of each is evaluated for allylic, benzylic, aliphatic, and functionalized alcohols. Additionally, chiral nonracemic substrates as well as chemoselective and diastereoselective oxidations are investigated. In this study, the most convenient system for the Pd-catalyzed aerobic oxidation of alcohols is Pd(OAc)2 in combination with triethylamine. This system functions effectively for the majority of alcohols tested and uses mild conditions (3 to 5 mol % of catalyst, room temperature). Pd(IiPr)(OAc)2(H2O) (1) also successfully oxidizes the majority of alcohols evaluated. This system has the advantage of significantly lowering catalyst loadings but requires higher temperatures (0.1 to 1 mol % of catalyst, 60°C). A new catalyst is also disclosed, Pd(IiPr)(OPiv)2 (2). This catalyst operates under very mild conditions (1 mol %, room temperature, and air as the O2 source) but with a more limited substrate scope.
- Schultz, Mitchell J.,Hamilton, Steven S.,Jensen, David R.,Sigman, Matthew S.
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p. 3343 - 3352
(2007/10/03)
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- 1,3,4-oxadiazole derivatives and process for producing the same
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Oxadiazole derivatives represented by formula (I): (wherein R1represents a hydrogen atom or an amino-protective group; R2, R3, and R4each independently represents an alkyl group, a cycloalkyl group, a phenyl gro
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- Remarkable three-step-one-pot solution phase preparation of novel imidazolines utilizing a UDC (Ugi/de-Boc/cyclize) strategy
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This communication reveals the novel solution phase synthesis of an array of biologically relevant imidazolines in a remarkable 'three-step-one-pot' procedure, utilizing a Ugi/de-Boc/cyclization (UDC) strategy. Transformations are carried out in excellent yield by condensation of N-Boc-α-amino-aldehydes and supporting Ugi reagents. The described protocol represents a highly attractive solution phase procedure for the rapid generation of this class of molecule.
- Hulme, Christopher,Ma, Liang,Romano, Joseph,Morrissette, Matthew
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p. 7925 - 7928
(2007/10/03)
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- 1,4-DIAMINO-2,3-DIHYDROXYBUTANES
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There are provided novel 1,4 Diamine 2,3 Dihydroxybutanes useful as antiviral agents, pharmaceutical compositions containing them and processes for preparing such compounds.
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