- Silole Amino Acids with Aggregation-Induced Emission Features Synthesized by Hydrosilylation
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The synthesis of silole amino acids was achieved through hydrosilylation of alkene or alkyne-containing amino acids with 1-methyl-2,3,4,5-tetraphenyl-1H-silole, using Karstedt's catalyst with yield up to 95 % and without epimerization. After selective deprotection of carboxylic acid or amine functions respectively, C- or N-peptide coupling with an alanine moiety proved their possible incorporation into peptides. A model tripeptide was synthesized by solid phase synthesis with the N-Fmoc protected silole amino acid version. The silole moiety can be also grafted on a precursor peptide directly on the solid support. These amino acids and peptides exhibit AIE properties with λem ca. 500 nm and Δλ ca. 100 nm. This approach constitutes an alternative and promising strategy for incorporation of such AIE fluorogens to peptides.
- Arribat, Mathieu,Rémond, Emmanuelle,Richeter, Sébastien,Gerbier, Philippe,Clément, Sébastien,Cavelier, Florine
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Read Online
- ACYCLIC STEREOCONTROLLED SYNTHESIS OF (-)-DETOXININE
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Allylic oxidation of (2S)-N-t-butoxycarbonyl-2-amino-4-pentenoic acid methyl ester afforded, stereoselectively, a (2S,3R)-2-amino-3-hydroxyl derivative, which was converted to the unusual amino acid (-)-detoxinine via a chelation controlled aldol condensation followed by a pyrrolidine ring formation.
- Ohfune, Yasufumi,Nishio, Hideki
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Read Online
- Microelectrode Arrays, Dihydroxylation, and the Development of an Orthogonal Safety-Catch Linker
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Construction of larger molecular libraries on an addressable microelectrode array requires a method for recovering and characterizing molecules from the surface of any electrode in the array. This method must be orthogonal to the synthetic strategies needed to build the array. We report here a method for achieving this goal that employs the site-selective dihydroxylation reaction of a simple olefin.
- Yeh, Nai-Hua,Krueger, Ruby,Moeller, Kevin D.
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p. 5440 - 5444
(2021/07/26)
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- Aliphatic chain-containing macrocycles as diazonamide A analogs
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[Figure not available: see fulltext.] Aliphatic alkyl chain-containing 12–14-membered macrocycles have been designed as structural analogs of antimitotic natural product diazonamide A. Macrocycles were synthesized from 5-bromooxazole in 7 to 9 linear step
- Vitkovska, Viktorija,Zogota, Rimants,Kalnins, Toms,Zelencova, Diana,Suna, Edgars
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p. 586 - 602
(2020/06/10)
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- PROTEIN TYROSINE PHOSPHATASE INHIBITORS AND METHODS OF USE THEREOF
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Provided herein are compounds, compositions, and methods useful for inhibiting protein tyrosine phosphatase, e.g., protein tyrosine phosphatase non-receptor type 2 (PTPN2) and/or protein tyrosine phosphatase non-receptor type 1 (PTPN1), and for treating related diseases, disorders and conditions favorably responsive to PTPN 1 or PTPN2 inhibitor treatment, e.g., a cancer or a metabolic disease.
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Paragraph 00836
(2020/09/27)
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- The secondary structure of a heptapeptide containing trifluoromethyl-λ6-tetrafluorosulfanyl substituted amino acids
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Site specific introduction of the polar hydrophobic trifluoromethyl-λ6-tetrafluorosulfanyl (CF3SF4) group can effectively control the secondary structure of a heptapeptide, the minimum repeat unit of an α-helix. The struct
- Ikeda, Akari,Capellan, Aimée,Welch, John T.
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p. 8079 - 8082
(2019/09/19)
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- Divergent Access to Histone Deacetylase Inhibitory Cyclopeptides via a Late-Stage Cyclopropane Ring Cleavage Strategy. Short Synthesis of Chlamydocin
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A unified step-economical strategy for accessing histone deacetylase inhibitory peptides is proposed, based on the late-stage installation of multiple zinc-binding functionalities via the cleavage of the strained cyclopropane ring in the common pluripoten
- Elek, Gábor Zoltán,Koppel, Kaur,Zubrytski, Dzmitry M.,Konrad, Nele,J?rving, Ivar,Lopp, Margus,Kananovich, Dzmitry G.
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p. 8473 - 8478
(2019/10/16)
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- COMPOUNDS AS L-CYSTINE CRYSTALLIZATION INHIBITORS AND USES THEREOF
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A method of preventing or inhibiting L-cystine crystallization is disclosed, using the compounds of formula I: [in-line-formulae]R1a—[O]v-(-A-L-)m-A-[O]v—R1b [/in-line-formulae] wherein A, L, R1a, R1b, m, and v are as described herein. The compounds may be prepared as pharmaceutical compositions, and may be used for the prevention and treatment of conditions that are causally related to L-cystine crystallization, such as comprising (but not limited to) kidney stones.
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Paragraph 0319; 0321
(2018/11/21)
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- Design, synthesis and biological evaluation of C(4) substituted monobactams as antibacterial agents against multidrug-resistant Gram-negative bacteria
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A series of novel pyridone conjugated monobactams with various substituents at the (4) position were synthesized and evaluated for their antibacterial activities against a panel of multidrug-resistant (MDR) Gram-negative bacteria in vitro. Compounds 46d, 54 and 75e displayed good to moderate activities against P. aeruginosa, among which the activity of 75e against P. aeruginosa was comparable to that of BAL30072 under iron limitation condition. Compounds 35, 46d, 54, 56a, 56c and 56d exhibited good to excellent antibacterial activities against E. coli and K. pneumoniae, which were comparable or superior to that of BAL30072. In vitro liver microsomal stability was further evaluated and the results manifested that Compounds 35, 46d and 54 were metabolically stable in human liver microsomes.
- Kou, Qunhuan,Wang, Ting,Zou, Feng,Zhang, Shuhua,Chen, Qian,Yang, Yushe
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- Cross-Metathesis Approach to the Tricyclic Marine Alkaloids (-)-Fasicularin and (-)-Lepadiformine A
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A cross-metathesis protocol has been developed to provide facile access to highly hindered trisubstituted α-branched olefins, which when coupled with a cationic azaspirocyclization reaction, generates the marine alkaloids (-)-fasicularin 2 and a pro-forma synthesis of (-)-lepadiformine A 1.
- Burnley, James,Wang, Zhen J.,Jackson, W. Roy,Robinson, Andrea J.
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p. 8497 - 8505
(2017/08/23)
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- Tridentate Directing Groups Stabilize 6-Membered Palladacycles in Catalytic Alkene Hydrofunctionalization
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Removable tridentate directing groups inspired by pincer ligands have been designed to stabilize otherwise kinetically and thermodynamically disfavored 6-membered alkyl palladacycle intermediates. This family of directing groups enables regioselective remote hydrocarbofunctionalization of several synthetically useful alkene-containing substrate classes, including 4-pentenoic acids, allylic alcohols, homoallyl amines, and bis-homoallylamines, under Pd(II) catalysis. In conjunction with previous findings, we demonstrate regiodivergent hydrofunctionalization of 3-butenoic acid derivatives to afford either Markovnikov or anti-Markovnikov addition products depending on directing group choice. Preliminary mechanistic and computational data are presented to support the proposed catalytic cycle.
- O'Duill, Miriam L.,Matsuura, Rei,Wang, Yanyan,Turnbull, Joshua L.,Gurak, John A.,Gao, De-Wei,Lu, Gang,Liu, Peng,Engle, Keary M.
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supporting information
p. 15576 - 15579
(2017/11/14)
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- NOVEL QUINOLINE-SUBSTITUTED COMPOUND
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An object to be achieved by the present invention is to provide a novel compound having EGFR inhibitory effects and cell growth inhibitory effects, as well as a medication useful for the prevention and/or treatment of cancer based on the EGFR inhibitory effects. The present invention provides a compound represented by Formula (I) below, or a salt thereof.
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Paragraph 0536-0538
(2016/10/10)
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- Optically Pure, Structural, and Fluorescent Analogues of a Dimeric Y4 Receptor Agonist Derived by an Olefin Metathesis Approach
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The dimeric peptide 1 (BVD-74D, as a diastereomeric mixture) is a potent and selective neuropeptide Y Y4 receptor agonist. It represents a valuable candidate in developing traceable ligands for pharmacological studies of Y4 receptors
- Liu, Mengjie,Mountford, Simon J.,Richardson, Rachel R.,Groenen, Marleen,Holliday, Nicholas D.,Thompson, Philip E.
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supporting information
p. 6059 - 6069
(2016/07/26)
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- Z-SELECTIVE OLEFIN METATHESIS OF PEPTIDES
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The invention relates generally to the synthesis of modified amino acids and modified peptides in the presence of cyclometalated catalysts. The invention has utility in the fields of catalysis, organic synthesis, polymer chemistry, and industrial and fine
- -
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Paragraph 0379; 0380; 0381
(2016/08/03)
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- NOVEL QUINOLINE -SUBSTITUTED COMPOUND
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An object to be achieved by the present invention is to provide a novel compound having EGFR inhibitory effects and cell growth inhibitory effects, as well as a medication useful for the prevention and/or treatment of cancer based on the EGFR inhibitory effects. The present invention provides a compound represented by Formula (I) below, or a salt thereof.
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Paragraph 0355; 0356
(2016/08/10)
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- Insight into Transannular Cyclization Reactions to Synthesize Azabicyclo[X.Y.Z]alkanone Amino Acid Derivatives from 8-, 9-, and 10-Membered Macrocyclic Dipeptide Lactams
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An efficient method for synthesizing different functionalized azabicyclo[X.Y.0]alkanone amino acid derivatives has been developed employing electrophilic transannular cyclizations of 8-, 9-, and 10-membered unsaturated macrocycles to form 5,5-, 6,5-, 7,5-, and 6,6-fused bicylic amino acids, respectively. Macrocycles were obtained by a sequence featuring peptide coupling of vinyl-, allyl-, homoallyl-, and homohomoallylglycine building blocks followed by ring-closing metathesis. X-ray crystallographic analyses of the 8-, 9-, and 10-membered macrocyclic lactam starting materials as well as certain bicyclic amino acid products provided insight into their conformational preferences as well as the mechanism for the diastereoselective formation of specific azabicycloalkanone amino acids by way of transannular iodolactamization reactions. (Chemical Equation Presented).
- Atmuri, N. D. Prasad,Lubell, William D.
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p. 4904 - 4918
(2015/06/02)
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- Z-selective olefin metathesis on peptides: Investigation of side-chain influence, preorganization, and guidelines in substrate selection
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Olefin metathesis has emerged as a promising strategy for modulating the stability and activity of biologically relevant compounds; however, the ability to control olefin geometry in the product remains a challenge. Recent advances in the design of cyclom
- Mangold, Shane L.,Oleary, Daniel J.,Grubbs, Robert H.
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p. 12469 - 12478
(2014/11/07)
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- Efficient synthesis of novel glutamate homologues and investigation of their affinity and selectivity profile at ionotropic glutamate receptors
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A convenient synthesis of four new enantiomerically pure acidic amino acids is reported and their affinity at ionotropic glutamate receptors was determined. The new compounds are higher homologues of glutamic acid in which the molecular complexity has bee
- Pinto, Andrea,Tamborini, Lucia,Mastronardi, Federica,Ettari, Roberta,Romano, Diego,Nielsen, Birgitte,De Micheli, Carlo,Conti, Paola
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supporting information
p. 1980 - 1982
(2014/04/17)
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- Synthesis, structure, and function of pcp pincer transition-metal-complex- bound norvaline derivatives
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A PCP pincer palladium-complex-bound norvaline, Boc-l-[Pd]Nva-OMe, was synthesized and fully characterized by NMR, FT-ICR-MS, and X-ray crystallography. Selective N- and C-terminus transformations of Boc-l-[Pd]Nva-OMe were performed by conventional deprotection-condensation procedures to afford lipophilic palladium-bound norvaline derivatives without metal detachment. The N-/C-bisfunctionalized palladium-bound norvaline showed self-assembly properties, as evidenced by supramolecular gel formation. The catalytic activity of the supramolecular gel was assessed in the 1,4-conjugate addition of phenylboronic acid.
- Takaya, Hikaru,Iwaya, Takashi,Ogata, Kazuki,Isozaki, Katsuhiro,Yokoi, Tomoya,Yoshida, Ryota,Yasuda, Nobuhiro,Seike, Hirofumi,Takenaka, Toshio,Nakamura, Masaharu
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supporting information
p. 1910 - 1914
(2013/09/24)
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- Synthesis and self-assembly of NCN-pincer Pd-complex-bound norvalines
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The NCN-pincer Pd-complex-bound norvalines Boc-D/L-[PdCl(dpb)]Nva-OMe (1) were synthesized in multigram quantities. The molecular structure and absolute configuration of 1 were unequivocally determined by single-crystal X-ray structure analysis. The robustness of 1 under acidic/basic conditions provides a wide range of N-/C-terminus convertibility based on the related synthetic transformations. Installation of a variety of functional groups into the N-/C-terminus of 1 was readily carried out through N-Boc- or C-methyl ester deprotection and subsequent condensations with carboxylic acids, R 1COOH, or amines, R2NH2, to give the corresponding N-/C-functionalized norvalines R1-D/L-[PdCl(dpb)]Nva- R2 2-9. The dipeptide bearing two Pd units 10 was successfully synthesized through the condensation of C-free 1 with N-free 1. The robustness of these Pd-bound norvalines was adequately demonstrated by the preservation of the optical purity and Pd unit during the synthetic transformations. The lipophilic Pd-bound norvalines L-2, Boc-L-[PdCl(dpb)]Nva-NH-n-C 11H23, and L-4, n-C4H9CO-L- [PdCl(dpb)]Nva-NH-n-C11H23, self-assembled in aromatic solvents to afford supramolecular gels. The assembled structures in a thermodynamically stable single crystal of L-2 and kinetically stable supramolecular aggregates of L-2 were precisely elucidated by cryo-TEM, WAX, SAXS, UV/Vis, IR analyses, and single-crystal X-ray crystallography. An antiparallel β-sheet-type aggregate consisting of an infinite one-dimensional hydrogen-bonding network of amide groups and π-stacking of PdCl(dpb) moieties was observed in the supramolecular gel fiber of L-2, even though discrete dimers are assembled through hydrogen bonding in the thermodynamically stable single crystal of L-2. The disparate DSC profiles of the single crystal and xerogel of L-2 indicate different thermodynamics of the molecular assembly process. Metalated amino acids: A series of NCN-pincer Pd-complex-bound norvaline derivatives was successfully synthesized without loss of the optical purity and Pd unit. Efficient self-assembly properties of these Pd-norvalines were found to afford well-regulated Pd arrays both in the single crystal and in the supramolecular gel. A solvent-dependent configuration control of the Pd array was corroborated by means of single-crystal X-ray crystallography and cryo-TEM analysis. Copyright
- Ogata, Kazuki,Sasano, Daisuke,Yokoi, Tomoya,Isozaki, Katsuhiro,Yoshida, Ryota,Takenaka, Toshio,Seike, Hirofumi,Ogawa, Tetsuya,Kurata, Hiroki,Yasuda, Nobuhiro,Takaya, Hikaru,Nakamura, Masaharu
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supporting information
p. 12356 - 12375
(2013/09/23)
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- Stereoselective synthesis of unsaturated and functionalized L-NHBoc amino acids, using wittig reaction under mild phase-transfer conditions
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The stereoselective synthesis of a new amino acid phosphonium salt was described by quaternization of melting triphenylphosphine with the β-iodo NHBoc-amino ester, derived from l-aspartic acid. The deprotection of the carboxylic acid function to afford the phosphonium salt with a free carboxylic acid group was achieved by a palladium-catalyzed desallylation reaction. This phosphonium salt was used in the Wittig reaction with aromatic or aliphatic aldehydes and trifluoroacetophenone, under solid-liquid phase-transfer conditions in chlorobenzene and in the presence of K3PO4 as weak base, to afford the corresponding unsaturated amino acids without racemization. Thus, the reaction with substituted aldehydes allows to graft various functionalized groups on the lateral chain of the amino acid, such as trifluoromethyl, cyano, nitro, ferrocenyl, boronato, or azido. In addition, the reaction of the amino acid Wittig reagent with α,β-unsaturated aldehydes leads to amino acids bearing a diene on the lateral chain. Finally, this amino acid phosphonium salt appears to be a new powerful tool for the preparation of unsaturated and non-proteinogenic α-amino acids, directly usable for the synthesis of customized peptides.
- Remond, Emmanuelle,Bayardon, Jerome,Ondel-Eymin, Marie-Joelle,Juge, Sylvain
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p. 7579 - 7587
(2012/10/29)
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- Exploring Leishmania major Inositol Phosphorylceramide Synthase (LmjIPCS): Insights into the ceramide binding domain
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The synthesis of set of ceramide analogues exploring hydrophobicity in the acyl chains and the degree and nature of hydroxylation is described. These have been assayed against the parasitic protozoan enzyme LmjIPCS. These studies showed that whilst the C-3 hydroxyl group was not essential for turnover it provided enhanced affinity. Reflecting the membrane bound nature of the enzyme a long (C13) hydrocarbon ceramide tail was necessary for both high affinity and turnover. Whilst the N-acyl chain also contributed to affinity, analogues lacking the amide linkage functioned as competitive inhibitors in both enzyme and cell-based assays. A model that accounts for this observation is proposed.
- Mina, John G.,Mosely, Jackie A.,Ali, Hayder Z.,Denny, Paul W.,Steel, Patrick G.
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supporting information; experimental part
p. 1823 - 1830
(2011/04/26)
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- Progress towards the synthesis of piperazimycin A: synthesis of the non-proteogenic amino acids and elaboration into dipeptides
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This Letter describes the synthesis of the five non-proteogenic amino acids required for the total synthesis of piperazimycin A, and synthetic elaboration into multiple dipeptides. Importantly, this Letter details the first example of an elusive piperazic acid-piperazic acid coupling to form this key C5-C14 dipeptide.
- Phillip Kennedy,Lindsley, Craig W.
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scheme or table
p. 2493 - 2496
(2010/06/14)
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- HIV PROTEASE INHIBITORS
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Compounds of Formula I are disclosed: (I), wherein XA, k, R1, R2, R3, R4, R5, R5A, R6, R6A, R7 and R8 are defined herein. The compounds encompassed by Formula I include compounds which are HIV protease inhibitors and other compounds which can be metabolized in vivo to HIV protease inhibitors. The compounds and their pharmaceutically acceptable salts are useful for the prophylaxis or treatment of infection by HIV and the prophylaxis, treatment, or delay in the onset of AIDS. The compounds and their salts can be employed as ingredients in pharmaceutical compositions, optionally in combination with other antivirals, immunomodulators, antibiotics or vaccines.
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Page/Page column 115
(2009/05/29)
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- SUBSTITUTED AMINO CARBOXYLIC ACIDS
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Disclosed are compounds and pharmaceutically acceptable salts of formula (I): which are useful in the treatment of metabolic disorders related to insulin resistance, leptin resistance, or hyperglycemia. Compounds of the invention include inhibitors of Protein tyrosine phosphatases, in particular Protein tyrosine phosphatase-1B (PTP-1B), that are useful in the treatment of diabetes and other PTP mediated diseases, such as cancer, neurodegenerative diseases and the like. Also disclosed are pharmaceutical compositions comprising compounds of the invention and methods of treating the aforementioned conditions using such compounds.
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Page/Page column 226-227
(2008/06/13)
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- Catalytic asymmetric phase-transfer reactions using tartrate-derived asymmetric two-center organocatalysts
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A new highly versatile asymmetric two-center catalyst, tartrate-derived diammonium salt (TaDiAS), was designed and a catalyst library containing more than 70 new two-center catalysts was constructed. A variety of (S,S)- and (R,R)-TaDiAS were easily synthesized from diethyl L- and D-tartrate, respectively, using common and inexpensive reagents under operationally simple reaction conditions. TaDiAS was used in phase-transfer alkylations and Michael additions to afford various optically active α-amino acid equivalents in up to 93% yield. Moreover, dramatic counter anion effects were observed in phase-transfer catalysis (PTC) for the first time, making it possible to further improve reactivity and selectivity. These findings validate the usefulness of three-dimensional fine-tuning of the catalyst (acetal, Ar, and counter anion) for optimization. Recovery and reuse of the catalyst was also possible using simple procedures. The present asymmetric PTC was successfully applied to enantioselective syntheses of serine protease inhibitor aeruginosin 298-A and its analogues.
- Ohshima, Takashi,Shibuguchi, Tomoyuki,Fukuta, Yuhei,Shibasaki, Masakatsu
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p. 7743 - 7754
(2007/10/03)
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- Photolysis of diacyl peroxides: A radical-based approach for the synthesis of functionalized amino acids
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(Matrix presented) Photolysis of the amino acid derived symmetrical and unsymmetrical diacyl peroxides at 254 nm at low temperature (-78 to -196°C) generates various bis(amino acids) in a concise manner and with orthogonal protection. The methodology was
- Spantulescu, M. Daniel,Jain, Rajendra P.,Derksen, Darren J.,Vederas, John C.
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p. 2963 - 2965
(2007/10/03)
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- Enantioselective syntheses of aeruginosin 298-A and its analogues using a catalytic asymmetric phase-transfer reaction and epoxidation
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We developed a versatile synthetic process for aeruginosin 298-A as well as several attractive analogues, in which all stereocenters were controlled by a catalytic asymmetric phase-transfer reaction and epoxidation. Furthermore, drastic counteranion effects in phase-transfer catalysis were observed for the first time, making it possible to three-dimensionally fine-tune the catalyst (ketal part, aromatic part, and counteranion). Copyright
- Ohshima, Takashi,Gnanadesikan, Vijay,Shibuguchi, Tomoyuki,Fukuta, Yuhei,Nemoto, Tetsuhiro,Shibasaki, Masakatsu
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p. 11206 - 11207
(2007/10/03)
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- Hydroboration-Suzuki cross coupling of unsaturated amino acids; the synthesis of pyrimine derivatives
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Hydroboration of protected allylglycines with 9-BBN followed by Suzuki cross coupling of the resulting organoboranes proceeded smoothly giving a range of new bis-homophenylalanine and related derivatives in good yields (9 examples, 53-64%). One of the Suzuki coupling products has been elaborated to give the N-Cbz-protected natural product pyrimine. The hydroboration-Suzuki coupling of vinylglycine derivatives was also studied but was less efficient than with the allylglycine derivatives: the best results were obtained using disiamylborane·DMS as the hydroborating agent.
- Collier, Philip N,Campbell, Andrew D,Patel, Ian,Taylor, Richard J.K
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p. 6117 - 6125
(2007/10/03)
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- Versatile synthons for optically pure alpha-amino aldehydes and alpha-amino acids: (+)- and (-)-4,5-dialkoxy-2-oxazolidinones.
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Both enantiomers of trans-5-benzyloxy-4-methoxy- (BMOx) and trans-4,5-dimethoxy-2-oxazolidinones (DMOx), which are readily accessible from simple 2-oxazolone heterocycles, represent good candidates for a new class of chiral synthons for use in the preparation of optically pure alpha-amino aldehydes and alpha-amino acids, respectively.
- Morita,Nagasawa,Yahiro,Matsunaga,Kunieda
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p. 897 - 899
(2007/10/03)
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- The direct synthesis of novel enantiomerically pure α-amino acids in protected form via Suzuki cross-coupling
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Protected allylglycine has been hydroborated and the intermediate organoborane employed in Suzuki coupling reactions with a number of olefinic, aromatic and heteroaromatic bromides and iodides to produce a range of novel α-amino acids in good, unoptimised yields. (C) 2000 Elsevier Science Ltd.
- Collier,Campbell,Patel,Taylor
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p. 7115 - 7119
(2007/10/03)
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- 1,5-dimethyl-4-phenylimidazolidin-2-one-derived iminic glycinimides: Useful new reagents for practical asymmetric synthesis of α-amino acids
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New 1,5-dimethyl-4-phenylimidazolidin-2-one-derived acyclic chiral iminic glycine reagents have been prepared and diastereoselectively alkylated with activated alkyl halides and electrophilic olefins in the presence of lithium chloride under (a) strong bases (LHMDS, KOBu(t)) and low temperature (-78 °C,) conditions; (b) solid-liquid phase-transfer catalysis reaction (LiOH, TBAB, -20 °C) conditions, and (c) in the presence of organic bases (DBU, BEMP, TMG, -20 °C). In the case of dielectrophiles C- and N-alkylation takes place to afford heterocyclic derivatives. Hydrolysis of alkylated products has been carried out (a) in two-step procedures with LiOOH or LiOH followed by acidic hydrolysis or Dowex purification, (b) in one single-step under refluxing water to give the corresponding α-amino acid, (c) in the presence of DBU in methanol to provide N-protected α-amino acids methyl esters, or (d) by a protection-hydrolysis procedure to afford N-Boc-protected α-amino acids. The chiral imidazolidinone has generally been recovered in good yield. This methodology has been shown to be useful for the synthesis of acyclic and heterocyclic (S)- and (R)-α-amino acids.
- Guillena,Najera
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p. 7310 - 7322
(2007/10/03)
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- Enantioselective synthesis of unsaturated amino acids using p- methoxybenzylamine as an ammonia equivalent
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A versatile, non-alkylative enantioselective synthesis of unsaturated α-amino acids based on the Sharpless asymmetric epoxidation has been developed. Enantiomerically enriched trans epoxy alcohols bearing unsaturated substituents were prepared and submitted to regio- and stereospecific ring- opening with p-methoxybenzylamine as a nucleophile, leading to anti-3-(p- methoxybenzylamino)-1,2-diols which were further protected by reaction with Boc2O. The 1,2-diol fragment was then oxidatively cleaved by a sequential treatment with sodium periodate and sodium chlorite to afford the corresponding amino acid. Using this methodology, doubly N-protected (p- methoxybenzyl and Boc) allyl glycine, 3-butenyl glycine and 4-pentenyl glycine have been prepared in three synthetic steps from the corresponding allyl alcohols. As a demonstration of the orthogonal nature of the nitrogen protection, both protecting groups have been selectively removed from the fully protected amino ester. (C) 1999 Elsevier Science Ltd.
- Alcon, Montserrat,Moyano, Albert,Pericas, Miquel A.,Riera, Antoni
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p. 4639 - 4651
(2007/10/03)
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- Stereoselective, nonracemic synthesis of ω-borono-α-amino acids
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ω-Unsaturated α-amino acids are synthesized through condensation of allyl and propargyl bromides or of 9-bromoundecene with a Ni(II) complex of the Schiff base derived from glycine and BPB. Hydroboration with Ipc2BH followed by oxidation with acetaldehyde affords enantiomerically pure ω- borono-α-aminocarboxylic acids.
- Collet, Sylvain,Bauchat, Patrick,Danion-Bougot, Renee,Danion, Daniel
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p. 2121 - 2131
(2007/10/03)
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- Rapid syntheses of 3-amino-5-hydroxymethyl-γ-lactones from L- allylglycine
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(3R, 5R) and (3R, 5S) N-protected 3-amino-5-hydroxymethyl-γ-lactones were obtained by one dihydroxylation step from methyl N-protected L- allylglycinate.
- Girard, Anne,Greck, Christine,Genet, Jean Pierre
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p. 4259 - 4260
(2007/10/03)
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- N-(Boc)-L-(2-bromoallyl)-glycine: A versatile intermediate for the synthesis of optically active unnatural amino acids
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N(Boc)-L-(2-bromoallyl)-glycine (1) was synthesized from diethylacetamidomalonate and 2,3-dibromopropene in a one-pot procedure (75% overall yield). The enantiomers were efficiently separated via a tandem biocatalytic kinetic hydrolytic resolution. 1 was
- Leanna,Morton
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p. 4485 - 4488
(2007/10/02)
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- LES ORGANOCUPRATES DANS UNE NOUVELLE SYNTHESE D'AMINOACIDES ENANTIOMERIQUEMENT PURS
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A new general method of synthesis of optically pure α- amino esters was elaborated during studies on the reaction of organocuprates with tosyl and halogeno derivatives of L-serine and L-homoserine.
- Bajgrowicz, J. A.,Hallaoui, A. El,Jacquier, R.,Pigiere, Ch.,Viallefont, Ph.
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p. 1833 - 1845
(2007/10/02)
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