- Microwave-Assisted Ruthenium- and Rhodium-Catalyzed Couplings of α-Amino Acid Ester-Derived Phosphinamides with Alkynes
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Two different types of new phosphinamide α-amino ester derivatives have been prepared in moderate to high yields via ruthenium(II) and rhodium(III)-catalyzed ortho-C?H functionalization under microwave irradiation. Specifically, the ortho-alkenylated phosphinamides were produced through coupling of phosphinamides containing an α-substituted or α,α-disubstituted α-amino ester with internal alkynes under ruthenium catalysis. In contrast, Ru and the more effective Rh-catalyzed coupling of the α-unsubstituted glycine ester phosphinamide with alkynes resulted in formation of oxidative annulation products, phosphaisoquinolin-1-ones. The developed methods feature the use of easily accessible starting materials, short reaction time, exclusive E-stereoselectivity (for ortho-alkenylation) and good functional group tolerance. The alkenylation reaction was readily scaled up to gram scale. Furthermore, the obtained alkenylated phosphinamide could be transformed into P-containing dipeptides through hydrolysis of the ester group in the catalysis product and subsequent condensation with an α-amino ester.
- Li, Xue-Hong,Gong, Jun-Fang,Song, Mao-Ping
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supporting information
(2021/12/23)
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- Application of proteasome inhibitor in inhibition of novel coronavirus
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The invention provides application of a proteasome inhibitor in inhibition of a novel coronavirus or preparation of novel coronavirus inhibitors. The proteasome inhibitor has a structure represented by a formula (I) or isomers, pharmaceutically acceptable salts thereof and prodrugs thereof. According to the application, by applying the proteasome inhibitor to inhibition of the novel coronavirus, good inhibiting activity is obtained, and a novel treatment way of think is provided for diseases such as pneumonia caused by the novel coronavirus.
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Paragraph 0162-0165
(2021/06/22)
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- C2 symmetric copper (II) complexes of L-valine and L-phenyl alanine based chiral diimines for catalytic asymmetric Henry reaction
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New C2 symmetric chiral diimines were synthesized from the amino acids L-valine and L-phenyl alanine. In situ copper (II) complexes of the chiral diimine ligands were found to catalyze asymmetric Henry reaction. The chiral nitro aldols were formed in excellent yield (99%) and ee (99%). The synthetic utility of the chiral catalysts were screened with various substituted prochiral aromatic and heteroaromatic aldehydes. Possible catalytic cycle for the chiral diimine copper complex catalyzed asymmetric Henry reaction has been proposed. The stereoselectivity of the asymmetric Henry reaction was discussed based on the transition state in the catalytic cycle.
- Ananthi, Nallamuthu,Johnson, S. Jesu,Kumar, K. Vinoth,Nixon, Peter Daniel
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supporting information
(2021/05/19)
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- Modular Fragment Synthesis and Bioinformatic Analysis Propose a Revised Vancoresmycin Stereoconfiguration
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Elaborate fragments of the proposed stereostructure of the complex polyketide antibiotic vancoresmycin have been synthesized in a stereoselective fashion based on a modular and convergent approach. Significant nuclear magnetic resonance differences in one of these subunits compared with the natural product question the proposed stereoconfiguration. Consequently, an extensive bioinformatics analysis of the biosynthetic gene cluster was carried out, leading to a revised stereoconfigurational proposal for this highly potent antibiotic.
- Adamek, Martina,Essig, Sebastian,Kurz, Michael,Menche, Dirk,Sch?nenbroicher, Max,Seul, Maximilian,Spindler, Stefanie,Wingen, Lukas M.,Ziemert, Nadine
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supporting information
p. 1175 - 1180
(2021/01/13)
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- Translation of Mycobacterium Survival Strategy to Develop a Lipo-peptide based Fusion Inhibitor**
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The entry of enveloped virus requires the fusion of viral and host cell membranes. An effective fusion inhibitor aiming at impeding such membrane fusion may emerge as a broad-spectrum antiviral agent against a wide range of viral infections. Mycobacterium survives inside the phagosome by inhibiting phagosome–lysosome fusion with the help of a coat protein coronin 1. Structural analysis of coronin 1 and other WD40-repeat protein suggest that the trp-asp (WD) sequence is placed at distorted β-meander motif (more exposed) in coronin 1. The unique structural feature of coronin 1 was explored to identify a simple lipo-peptide sequence (myr-WD), which effectively inhibits membrane fusion by modulating the interfacial order, water penetration, and surface potential. The mycobacterium inspired lipo-dipeptide was successfully tested to combat type 1 influenza virus (H1N1) and murine coronavirus infections as a potential broad-spectrum antiviral agent.
- Sardar, Avijit,Lahiri, Aritraa,Kamble, Mithila,Mallick, Amirul I.,Tarafdar, Pradip K.
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supporting information
p. 6101 - 6106
(2021/02/01)
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- Palladium(II), silver(I), and gold(I) complexes of a new class of chiral bicyclic [1,2,3]-triazolooxazine derived N-heterocyclic carbenes (NHCs): Synthesis, structure and application studies
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A new class of chiral bicyclic [1,2,3]-triazolooxazine derived N-heterocyclic carbene (NHC) ligands was synthesised in its enantiopure form from commercially available, cheap amino acid without undertaking any chiral resolution. In particular, the bicycli
- Kumar Gangwar, Manoj,Dey, Shreyata,Prakasham,Ghosh, Prasenjit
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- Synthesis and Penicillin-binding Protein Inhibitory Assessment of Dipeptidic 4-Phenyl-β-lactams from α-Amino Acid-derived Imines
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Monocyclic β-lactams revive the research field on antibiotics, which are threatened by the emergence of resistant bacteria. A six-step synthetic route was developed, providing easy access to new 3-amino-1-carboxymethyl-4-phenyl-β-lactams, of which the penicillin-binding protein (PBP) inhibitory potency was demonstrated biochemically.
- Decuyper, Lena,Juki?, Marko,Sosi?, Izidor,Amoroso, Ana Maria,Verlaine, Olivier,Joris, Bernard,Gobec, Stanislav,D'hooghe, Matthias
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supporting information
p. 51 - 55
(2019/11/28)
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- Peptide-Catalyzed Fragment Couplings that Form Axially Chiral Non-C2-Symmetric Biaryls
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We have demonstrated that small, modular, tetrameric peptides featuring the Lewis-basic residue β-dimethylaminoalanine (Dmaa) are capable of atroposelectively coupling naphthols and ester-bearing quinones to yield non-C2-symmetric BINOL-type scaffolds with good yields and enantioselectivity. The study culminates in the asymmetric synthesis of backbone-substituted scaffolds similar to 3,3′-disubstituted BINOLs, such as (R)-TRIP, with good (94:6 e.r.) to excellent (>99.9:0.1 e.r.) enantioselectivity after recrystallization, and a diastereoselective net arylation of the minimally modified nonsteroidal anti-inflammatory drug (NSAID) naproxen.
- Coombs, Gavin,Sak, Marcus H.,Miller, Scott J.
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supporting information
p. 2875 - 2880
(2020/01/24)
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- Oxidative damage of proline residues by nitrate radicals (NO3): A kinetic and product study
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Tertiary amides, such as in N-acylated proline or N-methyl glycine residues, react rapidly with nitrate radicals (NO3) with absolute rate coefficients in the range of 4-7 × 108 M-1 s-1 in acetonitrile. The major pathway proceeds through oxidative electron transfer (ET) at nitrogen, whereas hydrogen abstraction is only a minor contributor under these conditions. However, steric hindrance at the amide, for example by alkyl side chains at the α-carbon, lowers the rate coefficient by up to 75%, indicating that NO3-induced oxidation of amide bonds proceeds through initial formation of a charge transfer complex. Furthermore, the rate of oxidative damage of proline and N-methyl glycine is significantly influenced by its position in a peptide. Thus, neighbouring peptide bonds, particularly in the N-direction, reduce the electron density at the tertiary amide, which slows down the rate of ET by up to one order of magnitude. The results from these model studies suggest that the susceptibility of proline residues in peptides to radical-induced oxidative damage should be considerably reduced, compared with the single amino acid.
- Nathanael, Joses G.,Nuske, Madison R.,Richter, Annika,White, Jonathan M.,Wille, Uta
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supporting information
p. 6949 - 6957
(2020/10/02)
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- Chiral Imidazolidin-4-one with catalytic amount of Dicationic ionic liquid act as a recoverable and reusable Organocatalyst for asymmetric Diels-Alder reaction
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Imidazolidin-4-one is used as a recoverable organocatalyst for the asymmetric Diels-Alder reaction in the presence of catalytic amount of dicationic ionic liquid and trifluoroacetic acid as a co-catalyst. The Diels-Alder reaction between model substrate cyclopentadiene and crotonaldehyde gave the product in 95% conversion and 87% ee of the endo-product. The catalyst was shown better reusability when the 20?mol% of dicationic ionic liquid was used and catalyst was reused upto 5 cycles, conversion remains upto 3 recycles but ee of endo-9 was slightly droped.
- Deepa,Yadav, Geeta Devi,Chaudhary, Pooja,Aalam, Mohd Jubair,Meena, Dhan Raj,Singh, Surendra
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- Mechanoresponsive, proteolytically stable and biocompatible supergelators from ultra short enantiomeric peptides with sustained drug release propensity
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Stimuli-responsive low molecular weight hydrogelators attract immense interest from diverse segments of biomedicine and biotechnology. Distinctly, herein we report newly synthesized enantiomeric ultrashort peptides of general formula Me-(CH2)8-CO-NH-CH(X)-COOH, where X = CH2Ph in hydrogelators I (l-Phe) and II (d-Phe) respectively, which display excellent self-assembling propensity in physiological buffer at room temperature. Interestingly these biomolecules were endowed with mechanoresponsiveness, injectability and high mechanical integrity as confirmed by rheological measurements. Importantly they revealed resistance towards proteolytic degradation. Indeed dose dependent cell viability studies using MTT assay in four different cell lines, namely PANC-1, S1, HCT-116 and MDAMB-231, further confirmed the biocompatibility of the hydrogelators in vitro. The structural aspect of β-sheets of the hydrogelators was concluded on the basis of temperature dependent NMR, IR, PXRD and computational studies. We developed a user friendly delivery system, hydrogel nanoparticles (HNPs), with our mechanoresponsive and biocompatible hydrogelators, as these particles exhibited promising influence due to their enhanced surface area. Also the HNPs revealed excellent drug release kinetics for the model drugs 5FU/doxorubicin under physiological conditions in a sustained manner depending on the physicochemical parameters of the drugs. Taking these results together we envision that our designed hydrogelators and the delivery vehicle generated therefrom might represent a promising tool for administration of significant drug concentrations at lesion sites for a prolonged period, thus providing a better strategy for quick pain relief, rapid recovery and reduced systemic side effects.
- Basu, Anindya,Christman, Ryann M.,Duttkonar, Anita,Harjit, Jeena,Mehra, Radha Rani,Mishra, Anil K.,Tiwari, Amit K.
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p. 6346 - 6354
(2020/05/13)
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- Synthesis and antimalarial activity of (S)-methyl-(7-chloroquinolin-4-ylthio)acetamidoalquilate derivatives
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The synthesis of five new (S)-methyl-(7-chloroquinolin-4-ylthio)acetamidoalquilate derivatives is carried out under a modified version of the Steglich esterification reaction between different l-amino acid methyl esters and 2-(7-chloroquinolin-4-ylthio)acetic acid. Two of the compounds showed significant inhibition (>50%) of β-hematin formation. The two active structures were tested in vivo as potential antimalarials in mice infected with Plasmodium berghei ANKA, a chloroquine susceptible strain. Compounds 6b and 6e exhibited antimalarial activity comparable to that of chloroquine.
- Colmenarez, Custodiana,Acosta, María,Rodríguez, Miguel,Charris, Jaime
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p. 161 - 166
(2020/01/09)
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- The synthesis and characterization of tetramic acid derivatives as Mdm2-p53 inhibitors
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We present syntheses, prediction of tautomer forms and activities of the second generation of the Mdm2-p53 inhibitors that are based on the tetramic acid scaffold. The inhibitors do not contain 6-chloroindole. Binding of these compounds to Mdm2 was checked by two orthogonal methods: the fluorescence polarization and the 1H-15N HSQC NMR titration experiments. We discovered that the 3-phenylthio-substituted tetramic acid derivatives exist in solution solely in their enol forms which is in contrast to the similar 3-aliphatic substituted derivatives. The inhibitory (Ki) and dissociation (KD) constants are in low micromolar ranges with the best binding compound 9a having KD = 2.9 μM. Furthermore, our data show that the compounds indeed bind to the p53-binding pocket of Mdm2 and do not cause dimerization of Mdm2. The current work provides solid base for further rational design of the Mdm2/p53 inhibitors.
- Muszak, Damian,?abuzek, Beata,Brela, Mateusz Z.,Twarda-Clapa, Aleksandra,Czub, Miroslawa,Musielak, Bogdan,Surmiak, Ewa,Holak, Tad A.
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p. 161 - 174
(2019/04/26)
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- Aldehyde-mediated bioconjugation: Via in situ generated ylides
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A technically simple approach for rapid, high-yielding and site-selective bioconjugation has been developed for both in vitro and cellular applications. This method involves the generation of maleimido-phosphonium ylides via 4-nitrophenol catalysis under physiological conditions followed by their Wittig reactions with aldehyde-appended biomolecules.
- Parmar, Sangeeta,Pawar, Sharad P.,Iyer, Ramkumar,Kalia, Dimpy
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supporting information
p. 14926 - 14929
(2019/12/24)
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- In search of bioinspired hydrogels from amphiphilic peptides: A template for nanoparticle stabilization for the sustained release of anticancer drugs
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The development of potent stimuli-responsive hydrogels has rapidly expanded in the last decades due to their diversified applications in the field of biomedicines. In accordance with this drift, herein, we aimed at modulating a series of amphiphilic peptide analogues with the general formula Me-(CH2)14-CO-NH-CH(X)-COOH, where X = CH2Ph in hydrogelators I (l-Phe) and II (d-Phe) and X = CH2Ph(OH) in hydrogelator III (l-Tyr), which displayed an excellent propensity to immobilize water at room temperature with a minimum gelation concentration of 0.04%/0.05%/0.02% w/v for hydrogelators I-III, respectively, regardless of their configuration at the C-terminal centre. To validate this threshold concentration difference, we performed computational analysis that demonstrated the ability of the side-chains of hydrogelators I and III to remain highly planar with the methylene units of the amphiphile and aromatic rings, promoting favourable correspondence through van der Waals forces and pi-pi stacking. Consequently hydrogelators I and III self-assembled in an ordered organisation superior to hydrogelator II. Furthermore, the spectroscopic and microscopic experiments revealed that the hydrogelators manifested a β-sheet conformation and nanofibrous morphology at the supramolecular level. As observed visually and additionally confirmed by differential scanning calorimetry (DSC) and rheological measurements, the hydrogels exhibited thermo-reversibility, injectability and high mechanical strength. Importantly, these biomaterials were also found to be resistant towards proteolytic degradation and non-cytotoxic in the cell line HEK 293 using a dose-dependant cell viability assay. To date, the development of a structured approach for the release of drugs in a predictable manner from an optimised formulation, using peptide-based hydrogel nanoparticles as a delivery system remains in its infancy. Hence, we developed hydrogel nanoparticles (HNPs) with our fabricated amphiphilic peptides that exploited the weak noncovalent interactions for their fabrication, unlike other cross-linked polymers that require strong covalent or ionic bonds for their formation. Interestingly, the as-synthesized nanoparticles showed an unprecedented ability to release the anticancer drugs 5-fluoro uracil/doxorubicin at physiological conditions depending on the physico-chemical parameters of the drugs. We believe that the reported injectable, biocompatible, amphiphilic peptide-based hydrogels hold future promise as a potential tool to transport drugs to a targeted site at a greater concentration, thus relieving the patient from surgical injury and simultaneously aiding in a faster recovery.
- Mehra, Radha Rani,Tiwari, Priyanka,Basu, Anindya,Duttkonar, Anita
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p. 11666 - 11678
(2019/07/31)
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- Benzoazepine-Fused Isoindolines via Intramolecular (3 + 2)-Cycloadditions of Azomethine Ylides with Dinitroarenes
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Aminobenzaldehydes bearing a pendant 3,5-dinitrophenyl group react thermally with N-substituted α-amino acids to form unprecedented benzoazepine-fused isoindolines. The reaction proceeds via a dearomatization/rearomatization sequence involving an intramolecular (3 + 2)-cycloaddition between the in situ formed azomethine ylide and the dinitroarene. Various glycine derivatives are tolerated as well as branched substrates based on cyclic, α-mono-, and α,α-disubstituted amino acids, giving single diastereomers in many cases. The method is scalable and gives products with a nitro group ready for further manipulation.
- Wales, Steven M.,Rivinoja, Daniel J.,Gardiner, Michael G.,Bird, Melissa J.,Meyer, Adam G.,Ryan, John H.,Hyland, Christopher J. T.
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supporting information
p. 4703 - 4708
(2019/06/27)
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- Hydroxyphosphinylacetic acid as a chiral auxiliary compound
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The aim of the presented research was to check whether 2-hydroxy-2-(ethoxyphenylphosphinyl)acetic acid is a versatile chiral phosphonic auxiliary (readily seen in 31P NMR). The preliminary studies indicate that this compound may be used as chiral derivatizing agents for amines and alcohols, since the separation of selected examples of diastereomeric alcohols and amines in 31P NMR spectra was found to be satisfactory. The preliminary research about using this compound as a CSA are also promising.
- Majewska, Paulina
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p. 585 - 590
(2019/01/04)
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- ((S)-3-Mercapto-2-methylpropanamido)acetic acid derivatives as metallo-β-lactamase inhibitors: Synthesis, kinetic and crystallographic studies
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The emergence and global spread of metallo-β-lactamase (MBL) mediated resistance to almost all β-lactam antibacterials poses a serious threat to public health. Since no clinically useful MBL inhibitors have been reported, there is an urgent need to develop new potent broad-spectrum MBL inhibitors effective against antibacterial resistance. Herein, we synthesized a set of 2-substituted ((S)-3-mercapto-2-methylpropanamido) acetic acid derivatives, some of which displayed potent inhibition with high ligand efficiency to the clinically relevant MBL subtypes, Verona Integron-encoded MBL (VIM)-2 and New Delhi MBL (NDM)-1. Kinetic studies revealed that the inhibitors are not strong zinc chelators in solution, and they bind reversibly to VIM-2 but dissociate very slowly. Crystallographic analyses revealed that they inhibit VIM-2 via chelating the active site zinc ions and interacting with catalytically important residues. Further cell- and zebrafish-based assays revealed that the inhibitors slightly increase susceptibility of E. coli cells expressing VIM-2 to meropenem, and they have no apparent toxicity to the viability of HEK293T cells and the zebrafish embryogenesis.
- Liu, Sha,Jing, Li,Yu, Zhu-Jun,Wu, Chengyong,Zheng, Yongxiang,Zhang, En,Chen, Qiang,Yu, Yamei,Guo, Li,Wu, Yong,Li, Guo-Bo
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p. 649 - 660
(2018/02/10)
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- Structure-activity relationship of clovamide and its related compounds for the inhibition of amyloid β aggregation
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Alzheimer's disease (AD), a neurodegenerative disorder, is characterized by aggregation of amyloid β-protein (Aβ). Aβ aggregates through β-sheet formation and induces cytotoxicity against neuronal cells. Inhibition of Aβ aggregation by naturally occurring compounds is thus a promising strategy for the treatment of AD. We have already reported that caffeoylquinic acids and phenylethanoid glycosides, which possess two or more catechol moieties, strongly inhibited Aβ aggregation. Clovamide (1) containing two catechol moieties, isolated from cacao beans (Theobroma cacao L.), is believed to exhibit preventive effects on Aβ aggregation. To investigate the structure-activity relationship of clovamide (1) for the inhibition of Aβ aggregation, we synthesized 1 and related compounds 2–11 through reaction between L-DOPA, D-DOPA, L-tyrosine, or L-phenylalanine and caffeic acid, p-coumaric acid, or cinnamic acid, and compounds 12 and 13 were derived from 1. Among tested compounds 1–13, those containing one or two catechol moieties exhibited potent anti-aggregation activity, whereas the non-catechol-type related compounds showed little or no activity. This suggests that at least one catechol moiety is essential for inhibition of Aβ42 aggregation, and this activity increases depending on the number of catechol moieties. Consequently, clovamide (1) and its related compounds may be a promising therapeutic option for inhibiting Aβ-mediated pathology in AD.
- Tsunoda, Tatsuhiko,Takase, Mio,Shigemori, Hideyuki
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p. 3202 - 3209
(2018/05/05)
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- Enantioseparation of Sulfoxides and Nitriles by Inclusion Crystallization with Chiral Organic Salts Based on l-Phenylalanine
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Enantioselective inclusion of aromatic sulfoxides and nitriles was achieved in a host framework created by organic salts comprising achiral benzoic acids and a chiral primary amine (1a) derived from l-phenylalanine. Tuning of the combined achiral acid component successfully changed the chiral recognition ability of the organic salts. The guest molecules were hydrogen-bonded to form three-component inclusion crystals, and the enantiomers of nitriles and sulfoxides were separated with high selectivity up to 92 and 98 % ee. As far as we know, this is the first example of the enantioseparation of non-functionalized aromatic nitriles.
- Kodama, Koichi,Kanai, Hayato,Shimomura, Yuki,Hirose, Takuji
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supporting information
p. 1726 - 1729
(2018/04/24)
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- Efficient synthesis of novel conjugated 1,3,4-oxadiazole-peptides
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We were interested in the design and synthesis of novel bioisosteric analogues of leuprolide acetate containing the oxadiazole moiety at the C- or N-terminal of the peptide. An efficient approach for the synthesis of 2-amino-1,3,4-oxadiazoles through the reaction of hydrazide with ammonium thiocyanate and desulfurization reaction of the thiosemicarbazides using different coupling reagents was employed. These compounds are bioisosteres of the amide bond. Furthermore, the coupling of 2-amino-1,3,4-oxadiazoles at the C-terminal of leuprolide analogues was carried out, using a coupling reagent in the solution phase. On the other hand, the addition of a 2-amino-1,3,4-oxadiazole to the N-terminal of the peptide sequence was carried out through the reaction of the 2-amino-1,3,4-oxadiazole with succinic anhydride that led to the formation of a carboxylic acid moiety. Addition of the synthesized oxadiazole containing carboxylic acid to the peptide sequence was performed using a coupling reagent and on the surface of the resin. The synthesized peptides containing the oxadiazole moiety at the C- or N-terminal of the peptide sequence are peptidomimetics of leuprolide acetate. All of the synthesized peptides were purified using preparative HPLC and their structures were confirmed using HR-MS (ESI).
- Golmohammadi, Farhad,Balalaie, Saeed,Hamdan, Fatima,Maghari, Shokoofeh
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supporting information
p. 4344 - 4351
(2018/03/21)
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- An Optically Active Polymer for Broad-Spectrum Enantiomeric Recognition of Chiral Acids
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Recognition of enantiomers of chiral acids by anion–π or lone pair–π interactions has not yet been investigated but is a significant and attractive challenge. This study reports an optically active polymer-based supramolecular system with capabilities of discriminating enantiomers of various chiral acids. The polymer featuring alternate π-acidic naphthalenediimides (NDIs) and methyl l-phenylalaninates in the backbone exhibits an unprecedented slow self-assembly process that is susceptible to perturbation by various chiral acids. Thus, the combination of anion–π or lone pair–π interactions and sensitivity of the polymeric self-assembly process to external chiral species endows the system with recognition capabilities. This is the first time that anion–π or lone pair–π interactions have been applied in the recognition of enantiomers of various chiral acids with a single system. The results shed light on new strategies for material design by integrating π-acidic aromatic systems and chiral building blocks to afford relevant advanced functions.
- Yan, Jijun,Kang, Chuanqing,Bian, Zheng,Ma, Xiaoye,Jin, Rizhe,Du, Zhijun,Gao, Lianxun
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supporting information
p. 5824 - 5829
(2017/04/28)
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- Synthesis and Deployment of an Elusive Fluorovinyl Cation Equivalent: Access to Quaternary α-(1′-Fluoro)vinyl Amino Acids as Potential PLP Enzyme Inactivators
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Developing specific chemical functionalities to deploy in biological environments for targeted enzyme inactivation lies at the heart of mechanism-based inhibitor development but also is central to other protein-tagging methods in modern chemical biology including activity-based protein profiling and proteolysis-targeting chimeras. We describe here a previously unknown class of potential PLP enzyme inactivators; namely, a family of quaternary, α-(1′-fluoro)vinyl amino acids, bearing the side chains of the cognate amino acids. These are obtained by the capture of suitably protected amino acid enolates with β,β-difluorovinyl phenyl sulfone, a new (1′-fluoro)vinyl cation equivalent, and an electrophile that previously eluded synthesis, capture and characterization. A significant variety of biologically relevant AA side chains are tolerated including those for alanine, valine, leucine, methionine, lysine, phenylalanine, tyrosine, and tryptophan. Following addition/elimination, the resulting transoid α-(1′-fluoro)-β-(phenylsulfonyl)vinyl AA-esters undergo smooth sulfone-stannane interchange to stereoselectively give the corresponding transoid α-(1′-fluoro)-β-(tributylstannyl)vinyl AA-esters. Protodestannylation and global deprotection then yield these sterically encumbered and densely functionalized quaternary amino acids. The α-(1′-fluoro)vinyl trigger, a potential allene-generating functionality originally proposed by Abeles, is now available in a quaternary AA context for the first time. In an initial test of this new inhibitor class, α-(1′-fluoro)vinyllysine is seen to act as a time-dependent, irreversible inactivator of lysine decarboxylase from Hafnia alvei. The enantiomers of the inhibitor could be resolved, and each is seen to give time-dependent inactivation with this enzyme. Kitz-Wilson analysis reveals similar inactivation parameters for the two antipodes, L-α-(1′-fluoro)vinyllysine (Ki = 630 ± 20 μM; t1/2 = 2.8 min) and D-α-(1′-fluoro)vinyllysine (Ki = 470 ± 30 μM; t1/2 = 3.6 min). The stage is now set for exploration of the efficacy of this trigger in other PLP-enzyme active sites.
- McCune, Christopher D.,Beio, Matthew L.,Sturdivant, Jill M.,De La Salud-Bea, Roberto,Darnell, Brendan M.,Berkowitz, David B.
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supporting information
p. 14077 - 14089
(2017/10/17)
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- Chiral-pool synthesis of 1,2,4-trisubstituted 1,4-diazepanes as novel σ1 receptor ligands
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Starting from enantiomerically pure amino acids, 1,4-diazepanes with various substituents in 1, 2, and 4-position were synthesized following the late stage diversification strategy. The key step in the formation of the seven-membered ring was the intramolecular EDC coupling of amino acids 15, 26, and 39. The configuration in 2-position does not influence the σ1 affinity and selectivity over related receptors. A cyclohexylmethyl or a butyl group are the preferred substituents in 4-position, whereas a methyl moiety in 2-position and a (substituted) benzyl moiety in 1-position result in the highest σ1 affinity. These results fit nicely to the reported σ1 pharmacophore models. The compounds did not inhibit the structurally related fungal enzyme sterol Δ8,7-isomerase, but showed inhibition of diverse enzymes in late cholesterol biosynthesis at high concentrations. In a screening against more than 50 target proteins, (2S)-1-benzyl-4-(4-methoxybenzyl)-2-methyl-1,4-diazepane ((S)-28b, Ki(σ1) = 0.86 nM) showed a clean receptor profile. The dose dependent potentiation of electrically stimulated contractions of guinea pig vas deferens indicates σ1 agonistic activity of (S)-28b. Even at a dose of 100 mg/kg (S)-28b did not induce severe toxic or behavioral effects in the Irwin screen. Clear cognition enhancing effects were observed for (S)-28b after inducing amnesia by scopolamine.
- Fanter, Lena,Müller, Christoph,Schepmann, Dirk,Bracher, Franz,Wünsch, Bernhard
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p. 4778 - 4799
(2017/10/05)
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- The reactions of α-amino acids and α-amino acid esters with high valent transition metal halides: synthesis of coordination complexes, activation processes and stabilization of α-ammonium acylchloride cations
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Titanium tetrachloride smoothly reacted with a selection of α-amino acids (aaH) in CH2Cl2 affording yellow to orange solid coordination compounds, 1a-d, in 70-78% yields. The salts [NHEt3][TiCl4(aa)], 2a-b, were obtained from TiCl4/aaH/NEt3 (aa = l-phenylalanine, N,N-dimethylphenylalanine), in 60-65% yields. The complex , 3, was isolated from the reaction of l-proline with NbCl5/NHiPr2, performed in CH2Cl2 at room temperature. The X-ray structure of 3 features a bridging (E)-1,2-bis(3,4-dihydro-2H-pyrrol-5-yl)ethene-1,2-diolate ligand, resulting from the unprecedented C-C coupling between two proline units. Unusually stable α-ammonium acyl chlorides were prepared by the reactions of PCl5/MCln (MCln = NbCl5, WCl6) with l-proline, N,N-dimethylphenylalanine, sarcosine and l-methionine. MX5 (M = Nb, Ta; X = F, Cl) reacted with l-leucine methylester and l-proline ethylester to give ionic coordination compounds, [MX4L2][MX6] (M = Nb, L = Me2CHCH2CH(NH2)CO2Me, X = F, 9; Cl, 11a; M = Nb, X = Cl, , 11c; Ta, 11d), in moderate to good yields. [NbCl5(Me2CHCH2CHNH3CO2Me)][NbCl6], 12, was isolated as a co-product of the reaction of NbCl5 with l-leucine isopropylester, and crystallographically characterized. The reaction of NbCl5 with l-serine isopropylester afforded NbCl3(OCH2CHNHCO2iPr), 13, in 66% yield. The activation of the ester O-R bond was observed in the reactions of l-leucine methyl ester with NbF5 and l-proline ethyl ester with MBr5 (M = Nb, Ta), these reactions proceeding with the release of EtF and EtBr, respectively. All the metal products were characterized by analytical and spectroscopic methods, while DFT calculations were carried out in order to provide insight into the structural and mechanistic aspects.
- Biancalana, Lorenzo,Bortoluzzi, Marco,Ferretti, Eleonora,Hayatifar, Mohammad,Marchetti, Fabio,Pampaloni, Guido,Zacchini, Stefano
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p. 10158 - 10174
(2017/02/15)
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- Novel thiazolidinedione-5-acetic-acid-peptide hybrid derivatives as potent antidiabetic and cardioprotective agents
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Thiazolidinediones (TZDs) are one of the important clinically established antidiabetic agents. Amino-acid and peptides have an advantage of better target selectivity and specificity. As hybrids, they also improved absorption and showed better bioavailability, which in turn makes them safer. Hence, here an effort has been made to synthesize hybrids of thiazolidinedione with amino-acids and peptides and evaluate their antidiabetic and cardioprotective effect in streptozotocin-nicotinamide (STZ-NA) induced Type 2 diabetes mellitus (T2DM) rat models. A series of 14 thiazolidinedione-5-acetic acid hybrids with of different amino-acids and peptide combinations were synthesized, characterized and further screened for antidiabetic and cardioprotective activity. Among all, six compounds T1 (SSDMA1), T4 (SSDMA4), T5 (SSDMA5), T7 (SDMA13), T9 (SSDMA15) and T13 (SSDMA49) showed better antioxidant activity and comparable % glucose uptake by yeast cells. Hence, the in vivo antidiabetic screening was done for these six compounds. Among all six T1, T7, T13 showed significant blood glucose level decrease compared to standard pioglitazone HCl. Also T1, T7 and T13 showed better antioxidant activity with lower IC50 value than standard ascorbic acid, and hence in vivo cardioprotective studies were done for these. The ECG studies showed that T1 (SSDMA1) and T7 (SSDMA13) were better effective than SDMA49 (T13) in restoring the normal functioning of the heart, thus may help in preventing the development of diabetic cardiomyopathy (DCM) and controlling T2DM.
- Maji,Samanta
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p. 1163 - 1172
(2017/02/23)
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- Three new amino acid derivatives from edible mushroom Pleurotus ostreatus
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Three new amino acid derivatives, oxalamido-L-phenylalanine methyl ester (1), oxalamido-L-leucine methyl ester (2), and lumichrome hydrolyzate (3), together with nine known compounds (4–12), were isolated from the solid culture of edible mushroom Pleurotu
- Lu, Xiao-Jie,Feng, Bao-Min,Chen, Shao-Fei,Zhao, Dan,Chen, Gang,Wang, Hai-Feng,Pei, Yue-Hu
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p. 1160 - 1171
(2017/09/30)
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- Design, synthesis, and in vitro and biological evaluation of potent amino acid-derived thiol inhibitors of the metallo-β-lactamase IMP-1
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There are currently no clinically available inhibitors of metallo-β-lactamases (MBLs). These enzymes confer resistance to bacteria against a broad range of commonly used β-lactam antibiotics, and are produced by an increasing number of bacterial pathogens. In this study, several thiol derivatives of l-amino acids were designed and synthesized, and their inhibitory effects against the metallo-β-lactamase IMP-1 (subclass B1) were investigated. The most potent compound, derived from l-tyrosine, exhibited competitive inhibition, with a Ki of 86 nM. The ability of this compound to render MBL-expressing bacteria susceptible to imipenem was examined. Reductions in MIC values up to 5.2 - fold were observed.
- Arjomandi, Omid Khalili,Hussein, Waleed M.,Vella, Peter,Yusof, Yusralina,Sidjabat, Hanna E.,Schenk, Gerhard,McGeary, Ross P.
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p. 318 - 327
(2016/04/05)
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- Phosphoramidate protides of five flavones and their antiproliferative activity against HepG2 and L-O2 cell lines
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A series of flavone-7-phosphoramidate derivatives were synthesized and tested for their antiproliferative activity in vitro against human hepatoma cell line HepG2 and human normal hepatic cell line L-O2. Compound 8d, 16d and 17d, incorporating the amino acid alanine, exhibited high inhibitory activity on HepG2 cell line with IC50 values of 9.0 μmol/L, 5.5 μmol/L and 6.6 μmol/L. The introduction of acyl groups played a pivotal role in the selective inhibition toward human hepatoma HepG2 cells, except for compound 8a, 9a and 16b. Compound 8d, 16d and 17d could significantly induce G2/M arrest in HepG2 cells. Specially, Compound 16d could lead early apoptosis in HepG2 cells.
- Li, Yue-Qing,Yang, Fei,Wang, Liu,Cao, Zhi,Han, Tian-Jiao,Duan, Zhe-Ang,Li, Zhen,Zhao, Wei-Jie
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p. 196 - 208
(2016/05/02)
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- TRIPEPTIDE BORONIC ACID OR BORONIC ESTER, PREPARATIVE METHOD AND USE THEREOF
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The present invention discloses proteasome inhibitors of tripeptide boronic acids or boronic esters represented by Formula (I), preparative method and use thereof. The proteasome inhibitors are therapeutical agents for treating malignant tumor, various nervous system degenerative diseases, muscle cachexia or diabetes, wherein the malignant tumor is leukemia, gastric cancer, hepatocarcinoma or nasopharyngeal carcinoma.
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Paragraph 0035
(2016/11/07)
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- Mechanochemical Encapsulation of Fullerenes in Peptidic Containers Prepared by Dynamic Chiral Self-Sorting and Self-Assembly
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Molecular capsules composed of amino acid or peptide derivatives connected to resorcin[4]arene scaffolds through acylhydrazone linkers have been synthesized using dynamic covalent chemistry (DCC) and hydrogen-bond-based self-assembly. The dynamic character of the linkers and the preference of the peptides towards self-assembly into β-barrel-type motifs lead to the spontaneous amplification of formation of homochiral capsules from mixtures of different substrates. The capsules have cavities of around 800 ?3 and exhibit good kinetic stability. Although they retain their dynamic character, which allows processes such as chiral self-sorting and chiral self-assembly to operate with high fidelity, guest complexation is hindered in solution. However, the quantitative complexation of even very large guests, such as fullerene C60 or C70, is possible through the utilization of reversible covalent bonds or the application of mechanochemical methods. The NMR spectra show the influence of the chiral environment on the symmetry of the fullerene molecules, which results in the differentiation of diastereotopic carbon atoms for C70, and the X-ray structures provide unique information on the modes of peptide-fullerene interactions.
- Szymański, Marek,Wierzbicki, Micha?,Gilski, Miros?aw,J?drzejewska, Hanna,Sztylko, Marcin,Cmoch, Piotr,Shkurenko, Aleksander,Jaskólski, Mariusz,Szumna, Agnieszka
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supporting information
p. 3148 - 3155
(2016/03/23)
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- Colorimetric analysis of painting materials using polymer-supported polydiacetylene films
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Analysis of artworks and identification of their molecular components are of utmost importance for selecting proper conservation strategies and monitoring restoration. Accordingly, development of simple and readily applicable paint analysis assays is high
- Trachtenberg, Alexander,Malka, Orit,Kootery, Kaviya Parambath,Beglaryan, Stella,Malferrari, Danilo,Galletti, Paola,Prati, Silvia,Mazzeo, Rocco,Tagliavini, Emilio,Jelinek, Raz
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supporting information
p. 9054 - 9059
(2016/11/11)
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- Preparation of the optically pure N-methyl amino ester method and product
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The invention belongs to the field of organic synthesis of amino acids and discloses a method for preparing optically pure N-methyl amino-acid ester. The method comprises the following steps of carrying out esterification reaction on amino acid as a starting raw material and aldehyde to form an imine intermediate, carrying out reductive amination in the presence of palladium carbon, and carrying out hydrogenation and debenzylation to finally synthesize optically pure N-methyl amino-acid ester. The method has the advantages of simplicity in method, mild reaction conditions and good adaptability and side chains of D-type or L-type amino acid do not need to be protected.
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Paragraph 0045-0047
(2017/04/13)
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- Enantioselective Synthesis of 3-Arylquinazolin-4(3H)-ones via Peptide-Catalyzed Atroposelective Bromination
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We report the development of a tertiary amine-containing β-turn peptide that catalyzes the atroposelective bromination of pharmaceutically relevant 3-arylquinazolin-4(3H)-ones (quinazolinones) with high levels of enantioinduction over a broad substrate scope. The structure of the free catalyst and the peptide-substrate complex were explored using X-ray crystallography and 2D-NOESY experiments. Quinazolinone rotational barriers about the chiral anilide axis were also studied using density functional theory calculations and are discussed in light of the high enantioselectivities observed. Mechanistic studies also suggest that the initial bromination event is stereodetermining, and the major monobromide intermediate is an atropisomerically stable, mono-ortho-substituted isomer. The observation of stereoisomerically stable monobromides stimulated the conversion of the tribromide products to other atropisomerically defined products of interest. For example, (1) a dehalogenation Suzuki-Miyaura cross-coupling sequence delivers ortho-arylated derivatives, and (2) a regioselective Buchwald-Hartwig amination procedure installs para-amine functionality. Stereochemical information was retained during these subsequent transformations.
- Diener, Matthew E.,Metrano, Anthony J.,Kusano, Shuhei,Miller, Scott J.
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supporting information
p. 12369 - 12377
(2015/10/12)
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- Rapid Vortex Fluidics: Continuous Flow Synthesis of Amides and Local Anesthetic Lidocaine
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Thin film flow chemistry using a vortex fluidic device (VFD) is effective in the scalable acylation of amines under shear, with the yields of the amides dramatically enhanced relative to traditional batch techniques. The optimized monophasic flow conditions are effective in ≤80seconds at room temperature, enabling access to structurally diverse amides, functionalized amino acids and substituted ureas on multigram scales. Amide synthesis under flow was also extended to a total synthesis of local anesthetic lidocaine, with sequential reactions carried out in two serially linked VFD units. The synthesis could also be executed in a single VFD, in which the tandem reactions involve reagent delivery at different positions along the rapidly rotating tube with in situ solvent replacement, as a molecular assembly line process. This further highlights the versatility of the VFD in organic synthesis, as does the finding of a remarkably efficient debenzylation of p-methoxybenzyl amines.
- Britton, Joshua,Chalker, Justin M.,Raston, Colin L.
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supporting information
p. 10660 - 10665
(2015/07/20)
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- Synthesis of chiral (indol-2-yl)methanamines and insight into the stereochemistry protecting effects of the 9-phenyl-9-fluorenyl protecting group
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Tetrahydro-β-carbolines, a privileged structural feature in natural products and pharmaceutically active compounds, has been the cause for considerable research interest, spanning many decades. Herein is reported the synthesis of the structurally closely related compounds denoted as (indol-2-yl)methanamines, in 99% ee using amino acid starting materials, coupled with a 9-phenyl-9-fluorenyl (Pf) protecting group strategy. Furthermore a conformational study of Pf-protected α-amino carbonyl compounds were undertaken by means of DFT refined molecular mechanics calculation, X-ray crystallography measurements and NMR experiments in order to elucidate the stereochemical protecting properties induced by the Pf group. Herein is presented a highly efficient stereospecific synthesis of (indol-2-yl)methanamines from amino acids together with a mechanistic study on the stereochemistry protecting effects of the 9-phenyl-9-fluorenyl protecting group with the aid of DFT calculations, NMR and X-ray crystallography.
- Lood, Christopher S.,Laine, Aino E.,H?gn?sbacka, Antonia,Nieger, Martin,Koskinen, Ari M. P.
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p. 3793 - 3805
(2015/06/16)
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- Synthesis of MacMillan catalyst modified with ionic liquid as a recoverable catalyst for asymmetric Diels-Alder reaction
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MacMillan catalyst was modified with imidazolium ionic liquid by ester linkage and acts as recoverable and reusable catalyst for asymmetric Diels-Alder reactions. A Diels-Alder reaction between cyclopentadiene and crotonaldehyde was carried out using MacMillan catalyst modified with ionic liquid (5 mol%) using trifluoroacetic acid (5 mol%) as co-catalyst in acetonitrile-water (95 : 5) at room temperature, to give 94% conversion of Diels-Alder adduct with exo/endo (1 : 1.1) and 90% ee of endo product. The catalyst was recovered and reused up to 5 cycles with a slight decrease in ee and product conversion.
- Chauhan, ManMohan Singh,Kumar, Pramod,Singh, Surendra
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p. 52636 - 52641
(2015/06/25)
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- Nonenzymatic, enantioconvergent dynamic kinetic resolution (DKR) of racemic 2-(1H-pyrrol-1-yl)alkanoic acids as α-amino acid equivalents
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We report an effective dynamic kinetic resolution (DKR) system of racemic 2-(1H-pyrrol-1-yl)alkanoic acids, which consists of a rapid racemization step via an activating substrate and an enantio-discriminating step via catalytic esterification. The combination of pivalic anhydride as an activating agent, bis(α-naphthyl)methanol as an achiral alcohol, (R)-BTM as a chiral acyl-transfer catalyst, and Hunig's base converted racemic 2-(1H-pyrrol-1-yl)alkanoic acids to the corresponding chiral carboxylates, which can be transformed into chiral α-amino acid derivatives with maintained high enantiopurity.
- Tokumaru, Eri,Tengeiji, Atsushi,Nakahara, Takayoshi,Shiina, Isamu
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p. 1768 - 1770
(2016/02/18)
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- Peptide-catalyzed conversion of racemic oxazol-5(4 H)-ones into enantiomerically enriched α-amino acid derivatives
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We report the development and optimization of a tetrapeptide that catalyzes the methanolytic dynamic kinetic resolution of oxazol-5(4H)-ones (azlactones) with high levels of enantioinduction. Oxazolones possessing benzylic-type substituents were found to perform better than others, providing methyl ester products in 88:12 to 98:2 er. The mechanism of this peptide-catalyzed process was investigated through truncation studies and competition experiments. High-field NOESY analysis was performed to elucidate the solution-phase structure of the peptide, and we present a plausible model for catalysis.
- Metrano, Anthony J.,Miller, Scott J.
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p. 1542 - 1554
(2014/03/21)
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- Oxidative damage of aromatic dipeptides by the environmental oxidants NO2 and O3
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Irreversible oxidative damage at both aromatic side chains and dipeptide linkage occurs in the aromatic N- and C-protected dipeptides 7-11 upon exposure to the environmental pollutants NO2 and O3. The reaction proceeds through initial oxidation of the aromatic ring by in situ generated NO3, or by NO2, respectively, which leads to formation of nitroaromatic products. The indole ring in Phe-Trp undergoes oxidative cyclization to a pyrroloindoline. An important reaction pathway for dipeptides with less oxidisable aromatic side chains proceeds through fragmentation of the peptide bond with concomitant acyl migration. This process is likely initiated by an ionic reaction of the amide nitrogen with the NO2 dimer, N2O4. This journal is
- Gamon,White,Wille
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supporting information
p. 8280 - 8287
(2015/01/08)
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- Chiral N-hydroxybenzamides as potential catalysts for aerobic asymmetric oxidations
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Chiral N-hydroxybenzamides (1H-3H) have been synthesized as precursors of chiral short-lived N-oxyl radicals 1?-3?. The latter species have been generated by oxidation of 1H-3H with Pb(OAc)4 or hydrogen abstraction from 1H-3H by the tert-butoxyl radical and characterized by UV-vis spectrophotometry and EPR spectroscopy. Through a kinetic study of the hydrogen atom transfer processes promoted by 1?-3? from three chiral benzylic substrates (1-phenylethylamine, 1-phenylethanol, and α-vinylbenzyl alcohol), a moderate chiral discrimination has been found, with selectivity factors 0.5 ≥ kH(S)/kH(R) ≥ 2.
- Capraro, Maria Grazia,Franchi, Paola,Lanzalunga, Osvaldo,Lapi, Andrea,Lucarini, Marco
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p. 6435 - 6443
(2014/08/05)
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- Evaluation of two cyclic di-peptides as inhibitors of CCL2 induced chemotaxis
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Monocyte chemoattractant protein (CCL2) plays a major role in the recruitment of monocytes during inflammation. In this study we analysed properties of synthetic CCL2 inhibitors in inhibiting CCL2 mediated monocyte migration. Using trans-endothelial chemotaxis assays compounds C1 and C5 were found to significantly reduce CCL2 mediated migration. Flow based adhesion assays showed reduction in adhesion to VCAM-1 in the presence of 10 nM CCL2 and 50 μM C5 (p 0.05). Further studies with these compounds can aid in their development as anti-inflammatory therapies. The Royal Society of Chemistry 2013.
- Saleki, Mahsa,Colgin, Neil,Kirby, John A.,Cobb, Steven L.,Ali, Simi
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p. 860 - 864
(2013/08/26)
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- Molecular architectonics of stereochemically constrained π-complementary functional modules
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The elucidation of the complex factors that govern recognition events at the molecular level represents a daunting challenge in our quest to master the art of pre-programmed molecular assemblies. In this context, we present the molecular architectonics of thoughtfully designed amino acid appended functional molecules 1-5. Naphthalenediimide (NDI and pyrene were employed as functional modules due to their unusual topological shape similarity as well as complementary π-acidic and π-basic character, respectively. In addition, we show that dyads of such unusual functional modules energetically favour alternate assembly in contrast to the predominant self-sorted assembly observed for single-component systems. Moreover, by incorporating minute structural mutations into the amino acid side-chains of 1-5, we successfully tailored their assemblies into well-defined supramolecular architectures, namely supercoiled helices, twisted nanoribbons, nanobelts, comb-edged nanoflakes and nanosheets. A detailed analysis with the aid of experimental and theoretical studies has generated interesting insights into the factors that govern the recognition events at the molecular level. In a quest to master pre-programmed molecular assemblies, we show that alternate stacking over self-sorting of functional aromatic modules can be energetically controlled by smarter molecular design. Furthermore, by introducing structural mutations into the side-chain of amino acid auxiliaries, the molecular assemblies form tailored well-defined 1D and 2D supramolecular nanoarchitectures. Copyright
- Avinash,Samanta, Pralok K.,Sandeepa,Pati, Swapan K.,Govindaraju
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p. 5838 - 5847
(2013/09/23)
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- Asymmetric epoxidation of chalcones promoted by chiral schiff bases and amino alcohols
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A series of chiral ligands were conveniently prepared from L-phenylalanine and characterized. Their application to the asymmetric epoxidation of chalcone was studied. The results demonstrated that 3a were efficient catalysts for enantioselective epoxidation of chalcone in moderate yield (up to 58.6%) and high enantioselectivities (up to 90% e.e.).
- Shen, Tianhua,Li, Junqi,Cui, Funa,Zhou, Xiaocong,Chen, Xiaoli,Song, Qingbao
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p. 1354 - 1358
(2014/01/06)
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- Asymmetric Henry reaction catalyzed by Cu(I)-based chiral amino alcohol complex
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The Cu(I)-based complex prepared from (S)-2-(furan-2-yl-methylamino)-2- phenylethanol (5c) and CuCl was used as catalyst in enantioselective Henry reactions of arylaldehydes and nitromethane, which gave 89% ee and 95% yield at ambient temperature. The proposed catalytic cycle of an asymmetric Henry reaction was suggested. TUeBITAK.
- Shen, Tianhua,Qin, Quan,Ni, Hang,Xia, Ting,Zhou, Xiaocong,Cui, Funa,Li, Junqi,Ran, Deqiang,Song, Qingbao
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p. 966 - 977
(2013/12/04)
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- Solvent-induced helical assembly and reversible chiroptical switching of chiral cyclic-dipeptide-functionalized naphthalenediimides
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Understanding the roles of various parameters in orchestrating the preferential chiral molecular organization in supramolecular self-assembly processes is of great significance in designing novel molecular functional systems. Cyclic dipeptide (CDP) chiral auxiliary-functionalized naphthalenediimides (NCDPs 1-6) have been prepared and their chiral self-assembly properties have been investigated. Detailed photophysical and circular dichroism (CD) studies have unveiled the crucial role of the solvent in the chiral aggregation of these NCDPs. NCDPs 1-3 form supramolecular helical assemblies and exhibit remarkable chiroptical switching behaviour (M- to P-type) depending on the solvent composition of HFIP and DMSO. The strong influence of solvent composition on the supramolecular chirality of NCDPs has been further corroborated by concentration and solid-state thin-film CD studies. The chiroptical switching between supramolecular aggregates of opposite helicity (M and P) has been found to be reversible, and can be achieved through cycles of solvent removal and redissolution in solvent mixtures of specific composition. The control molecular systems (NCDPs 4-6), with an achiral or D-isomer second amino acid in the CDP auxiliary, did not show chiral aggregation properties. The substantial roles of hydrogen bonding and π-π interactions in the assembly of the NCDPs have been validated through nuclear magnetic resonance (NMR), photophysical, and computational studies. Quantum chemical calculations at the ab initio, semiempirical, and density functional theory levels have been performed on model systems to understand the stabilities of the right (P-) and left (M-) handed helical supramolecular assemblies and the nature of the intermolecular interactions. This study emphasizes the role of CDP chiral auxiliaries on the solvent-induced helical assembly and reversible chiroptical switching of naphthalenediimides.
- Manchineella, Shivaprasad,Prathyusha,Priyakumar, U. Deva,Govindaraju
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supporting information
p. 16615 - 16624
(2014/01/06)
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- Substituted 2-hydroxy-N-(arylalkyl)benzamides induce apoptosis in cancer cell lines
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Variously substituted 2-hydroxy-N-(arylalkyl)benzamides were prepared and screened for antiproliferative and cytotoxic activity in cancer cell lines in vitro. Five compounds, out of 33 showed single-digit micromolar IC50 values against several human cancer cell lines. One of the most potent compounds N-((R)-1-(4-chlorophenylcarbamoyl)-2-phenylethyl)-5-chloro-2-hydroxybenzamide (6k) reduced proliferation and induced apoptosis in the melanoma cell line G361 in a dose-dependent manner, as shown by decrease in 5-bromo-2′- deoxyuridine incorporation and increase in several apoptotic markers, including subdiploid population increase, activation of caspases and site-specific poly-(ADP-ribose)polymerase (PARP) cleavage.
- Imramovsky, Ale?,Jorda, Radek,Pauk, Karel,?ezní?ková, Eva,Du?ek, Jan,Hanusek, Ji?í,Kry?tof, Vladimír
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supporting information
p. 253 - 259
(2013/10/01)
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- NUCLEOSIDE DERIVATIVES, SYNTHESIS METHODS AND USES THEREOF FOR PREPARING ANTI-TUMOR AND ANTI-VIRUS MEDICAMENTS
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The present invention relates to the field of pharmacochemistry. Disclosed are fluorinated and azido-substituted pyrimidine nucleoside derivatives, and preparation methods and uses thereof. The structural formula is as shown (I). These compounds can be used for preparing medicaments for treating diseases such as tumors and viral infections, and can be used separately or in combination with other medicaments. The compounds also have effective activity against diseases such as tumors and viral infections, while having few side effects, and thus have potential application value.
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Paragraph 0062
(2013/07/25)
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- PYRIMIDINE NUCLEOSIDE DERIVATIVES, SYNTHESIS METHODS AND USES THEREOF FOR PREPARING ANTI-TUMOR AND ANTI-VIRUS MEDICAMENTS
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The present invention relates to the field of pharmacochemistry. Disclosed are fluorinated and azido-substituted pyrimidine nucleoside derivatives, and preparation methods and uses thereof. The structural formula is as shown (I). These compounds can be used for preparing medicaments for treating diseases such as tumors and viral infections, and can be used separately or in combination with other medicaments. The compounds also have effective activity against diseases such as tumors and viral infections, while having few side effects, and thus have potential application value.
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Paragraph 0068
(2013/11/19)
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- TRIPETIDE BORONIC ACID OR BORONIC ESTER, PREPARATIVE METHOD AND USE THEREOF
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The present invention discloses proteasome inhibitors of tripeptide boronic acids or boronic esters represented by Formula (I), preparative method and use thereof. The proteasome inhibitors are therapeutical agents for treating malignant tumor, various nervous system degenerative diseases, muscle cachexia or diabetes, wherein the malignant tumor is leukemia, gastric cancer, hepatocarcinoma or nasopharyngeal carcinoma.
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