- Cyclomaltooligosaccharide-assisted spectroscopic discrimination of phthalimido-derived amino acids through the formation of molecular aggregates
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Spectroscopic evidence was used to demonstrate the formation of molecular associates in an aqueous solution of phthalimido tryptophan. These molecular associates are loosely formed through π-π aromatic stacking, properties that are not sufficient to cause NMR spectroscopic enantiomeric discrimination. A cyclomaltooligosaccharide with a larger cavity, such as cyclomaltooctaose (γ-cyclodextrin), is capable of forming a ternary complex with these molecular associates and enhances π-π aromatic stacking interactions, resulting in NMR enantiomeric discrimination. Electrospray-ionization mass spectroscopy (ESIMS) and NOESY two-dimensional NMR spectroscopic methods were used to study these complexes. Association constants and thermodynamic data for these cyclomaltooligosaccharide complexes were also estimated.
- Jursic, Branko S.,Patel, Paresh K.
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- Palladium-Catalyzed Decarbonylation of Amino Acid Derivatives via C-C Bond and C-N Bond Dual Activations
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A unique decarbonylation of an amino acid derivative catalytic system has been established via palladium-catalyzed C-C bond and C-N bond dual activations. By employing 8-aminoquinoline as the directing group, this transformation has been found to facilitate the high chemoselectivity to decarbonylation of amino acid derivatives rather than intramolecular deamination or cross-dehydrogenative coupling reactions. This method provides a straightforward avenue for constructing diverse functionalized amide compounds in good to excellent yields. We proposed a possible reaction pathway that may go through the C-C bond and C-N bond dual activations on the basis of the mechanistic studies.
- Deng, Gongtao,Jiang, Yaojia,Jiao, Yongjuan,Li, Yingmei,Wu, Jiamin,Zhang, Jinli,Zhang, Zhengyu
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p. 17462 - 17470
(2021/12/02)
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- A Novel Class of 7-Membered Heterocyclic Compounds
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The work presented herein describes the synthesis of a formerly inaccessible class of heterocyclic compounds. The reaction relies on α-phthalimido-amides, which are readily prepared from amino acids in 2 simple reactions steps. Under amide activation conditions in which classical keteniminium ions are not formed, the nitrile solvent is incorporated into the new fused 7-membered ring system. Due to the absence of a keteniminium intermediate, the stereogenic information in the α-position is fully retained.
- Bauer, Adriano,Borsos, Eszter,Maulide, Nuno
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supporting information
p. 3971 - 3974
(2020/05/25)
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- Tetrasubstituted Furans by Nucleophile-Induced Cleavage of Carbonyl Ylide-DMAD Cycloadducts
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Compounds incorporating a 4-aza-8-oxabicyclo[3.2.1]oct-6-en-2-one moiety, which were prepared by a tandem carbenoid carbonyl ylide cyclization/[3+2]-cycloaddition reaction from ethyl 2-diazo-3-oxo-4-phthalimidobutanoates, undergo a nucleophile-induced two-bond ring cleavage when treated with protic heteronucleophiles. In this manner, tetrasubstituted furantricarboxylates, tethered with α-amino acids, esters, thioesters, and amides by a 2-carbonylphenyl moiety, are obtained.
- Dobesch, Matthias,Greiner, Julian,Maas, Gerhard
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p. 2987 - 3000
(2020/08/10)
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- Enantioselective Synthesis of N-Benzylic Heterocycles: A Nickel and Photoredox Dual Catalysis Approach
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Reported herein is a dual nickel- and photoredox-catalyzed modular approach for the preparation of enantioenriched N-benzylic heterocycles. α-Heterocyclic carboxylic acids, easily obtainable from common commercial material, are reported as suitable substrates for a decarboxylative strategy in conjunction with a chiral pyridine-oxazoline (PyOx) ligand, providing quick access to enantioenriched drug-like products. The presence of a directing group on the heterocyclic moiety is shown to be beneficial, affording improved stereoselectivity in a number of cases.
- Pezzetta, Cristofer,Bonifazi, Davide,Davidson, Robert W. M.
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supporting information
p. 8957 - 8961
(2019/11/11)
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- Synthesis and study of modified polyvinyl alcohol containing amino acid moieties as anticancer agent
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A series of new phthalimides compounds[3-7]a-i were synthesized from reaction of Malic anhydride, phthalic anhydride, nitro phthalic anhydride, 2-phenyl-4H-benzo[d][1,3]oxazin-4-one, 2-(4-nitrophenyl)-4H-benzo[d][1,3]oxazin-4-one with different amino acids as glycine, alanine, valine, leucine, isoleucine, serine, threonine, tyrosine and Phenyl alanine [1]a-i under fusion conditions. Compounds [3-7]a-i react with SOCl2 in the presence of benzene to produce compounds [8-12]a-i. Chemical modification of Poly(vinyl alcohol)were obtained by reaction of PVA with compounds [8-12]a-i using the dimethyl formamide to give compounds [13-17]a-i. The structure of the synthesized compounds was characterized by their analytical and spectral data as, IR spectra, 1H, 13C-NMR, Elemental analysis (CHN), UV-Vis Spectroscopy, Scanning electron microscopy (SEM), Antibacterial activity were screened via two kinds of bacteria. Also, anticancer activity were examined for most of the modified polyvinyl alcohol.
- Samir, Ali H.,Saeed, Ruwaidah S.,Matty, Fadhel S.
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p. 286 - 294
(2018/03/21)
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- Synthesis of Quaternary α-Fluorinated α-Amino Acid Derivatives via Coordinating Cu(II) Catalytic α-C(sp3)-H Direct Fluorination
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A coordinating, copper-catalyzed direct α-C(sp3)-H fluorination method has been developed to prepare vital quaternary α-fluorinated α-amino acid derivatives. A Cu(II) catalytic SET oxidative addition mechanism is proposed, involving a key fluoride-coupled Cu(II) charge transfer complex. The protocol can tolerate a rich variety of α-amino acids, for which the auxiliary group is removed in high yield and substituted for the direct preparation of dipeptide derivatives with detachable, single absolute configurations of the target compounds.
- Wei, Qiang,Ma, Yao,Li, Li,Liu, Qingfei,Liu, Zijie,Liu, Gang
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supporting information
p. 7100 - 7103
(2018/11/24)
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- General Synthesis of Amino Acid Salts from Amino Alcohols and Basic Water Liberating H2
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An atom-economical and environmentally friendly method to transform amino alcohols to amino acid salts using just basic water, without the need of pre-protection or added oxidant, catalyzed by a ruthenium pincer complex, is developed. Water is the solvent, the source of the oxygen atom of the carboxylic acid group, and the actual oxidant, with liberation of dihydrogen. Many important and useful natural and unnatural amino acid salts can be produced in excellent yields by applying this new method.
- Hu, Peng,Ben-David, Yehoshoa,Milstein, David
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supporting information
p. 6143 - 6146
(2016/06/09)
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- Pd-Catalyzed sequential β-C(sp3)-H arylation and intramolecular amination of δ-C(sp2)-H bonds for synthesis of quinolinones: Via an N,O-bidentate directing group
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The pharmacological importance of 2-quinolinone derivatives is well known. Herein, we developed an effective protocol for the synthesis of 2-quinolinone derivatives by palladium-catalyzed sequential β-C(sp3)-H arylation and selective intramolecular C(sp2)-H/N-H amination starting with aryl iodides and carboxylic acids. A novel directing group, glycine dimethylamide, was used in the synthesis. We synthesized various quinolinone derivatives, including 5-substituted quinolinones, which are difficult to obtain using the traditional pathway. The directing group could be easily removed and could be readily transformed into other useful functional groups.
- Guan, Mingyu,Pang, Yubo,Zhang, Jingyu,Zhao, Yingsheng
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supporting information
p. 7043 - 7046
(2016/06/09)
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- Design, synthesis and anti-cancer activity evaluation of podophyllotoxin-norcantharidin hybrid drugs
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In this study, we designed and synthesized eighteen podophyllotoxin-norcantharidin hybrid drugs which could exhibit more potent anti-cancer activity than the parent drugs. Through the anti-proliferation assay, the most potent anti-cancer agent was screened out, namely Q9 (IC50?=?0.88?±?0.18?μM against MCF-7 cell line), and it showed lower cytotoxicity against non-cancer cells, human embryonic kidney cells (293T) (IC50?=?54.38?±?3.78?μM). Additionally, based on the flow cytometry analysis result, it can cause a remarkable cell cycle arrest at G2/M phase and induce apoptosis in MCF-7 cells more significantly than podophyllotoxin or norcantharidin per se. Moreover, the expression of cell cycle relative protein CDK1 was up regulated while a protein required for mitotic initiation, Cyclin B1 was down regulated. Furthermore, according to the confocal microscopy observation results, it was shown that Q9 was a potent tubulin polymerization inhibitor and the effect is comparable to that of colchicine. For further investigation on the aforementioned mechanisms, we performed western blot experiments, thus finding the increase of the cleavage of PARP. Consistent with these new findings, molecular docking observations suggested that compound Q9 could be developed as a potential anticancer agent.
- Han, Hong-Wei,Qiu, Han-Yue,Hu, Cui,Sun, Wen-Xue,Yang, Rong-Wu,Qi, Jin-Liang,Wang, Xiao-Ming,Lu, Gui-Hua,Yang, Yong-Hua
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supporting information
p. 3237 - 3242
(2016/07/12)
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- Design, synthesis and mechanism of novel shikonin derivatives as potent anticancer agents
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In this study, a series of novel shikonin derivatives (30-49) were designed and synthesized and their anti-proliferative activities were evaluated against five different cancer cell lines, including HeLa, HepG2, MCF-7, BGC and A549. Some of the compounds show strong anti-proliferative effects against HeLa, HepG2 and MCF-7 with IC50 values ranging from 1.26 to 18.50 μM and show lower side effects towards normal cell lines as compared to shikonin. Compared to other compounds and shikonin itself, compound 40 displayed much stronger anti-proliferative effects against various cancer cell lines. Furthermore, the flow cytometry results demonstrated that compound 40 could obviously induce apoptosis in a dose- and time-dependent manner and also cause cell cycle arrest at the G2/M phase. For further investigation of the aforementioned mechanisms, we performed Western blot experiments and found that the cleavage of PARP and upstream caspase-3 increased; moreover, caspase-9 was activated by cleavage but not caspase-8. These aforementioned results also indicate that compound 40 could induce caspase-9 involved apoptosis and G2/M phase cell cycle arrest via the P21, p-CDC2 (Tyr15) pathway independent of P53.
- Baloch, Shahla Karim,Ma, Lin,Wang, Xue-Liang,Shi, Jing,Zhu, Yu,Wu, Feng-Yao,Pang, Yan-Jun,Lu, Gui-Hua,Qi, Jin-Liang,Wang, Xiao-Ming,Gu, Hong-Wei,Yang, Yong-Hua
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p. 31759 - 31767
(2015/04/22)
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- New fluorescent and colorimetric chemosensors based on the rhodamine detection of Hg2+ and Al3+ and application of imaging in living cells
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Employing the "OffeOn" switching of the spirocyclic moiety in Rhodamine B derivatives, three sensors were designed and characterized as new fluorescent probes for detecting Hg2+ and Al3+ in the environment, respectively. The first probe exhibited chromogenic and fluorogenic selectivity to detection of Hg2+ in methanol-H2O (4:6, v/v, HEPES, pH 7.0). The first and second probes displayed fluorescence intensity enhancement following Hg2+ coordination with limits of detection for Hg2+ at the ppb level. The limit of detection based on 3 blank/k was calculated to be 2.5 × 10-8 M and 4.2 × 10-8 M, respectively. The third probe contained a benzyl group which resulted in better selectivity for Al3+. Job's plot clearly suggested the formation of 1:1 complexation behavior between the three probes and Hg 2+ or Al3+. The three probes can be used as a fluorescent probe for monitoring Hg2+ or Al3+ in living cells with satisfying results, which demonstrates the value of the probes in practical applications in environmental and biological systems.
- Yan, Fanyong,Wang, Meng,Cao, Donglei,Yang, Ning,Fu, Yang,Chen, Li,Chen, Ligong
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- Synthesis and antiviral activity of novel 1,3,4-thiadiazine derivatives
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A series of novel 1,3,4-thiadiazine derivatives were synthesized via chemical optimization on phthiobuzone. Their anti-herpes simplex virus (HSV) activities in vitro were also tested. Several compounds exhibited more highly potent anti-HSV activity and much higher selectivity index (SI) values than those of phthiobuzone. The most potent anti-HSV compound was 4f, which showed marked inhibition against HSV-1 (IC50=77.04μg/ml) and HSV-2 (IC50=30.00μg/ml). Meanwhile it had low cytotoxicity (CC 50=1000.00μg/ml), resulting in high (SIHSV-1= 12.98, SIHSV-2=33.33, respectively). Furthermore, a computational study for prediction of absorption, distribution, metabolism, excretion (ADME) properties of compound 4f was performed by determination of topological polar surface area, absorption and Lipinski parameters.
- Yang, Yajun,Feng, Ziming,Jiang, Jianshuang,Yang, Yanan,Pan, Xiandao,Zhang, Peicheng
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scheme or table
p. 1016 - 1019
(2011/10/08)
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- The synthesis of N-acyl-2-hydroxymethyl aziridines of biological interest
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A practical synthesis of the title compounds from protected amino acylazides is described. All the compounds might be considered as a novel class of dipeptide isostere precursors; they all induce lymphocyte proliferation and protein production as observed from preliminary biological tests.
- Medjahed,Tabet Zatla,Kajima Mulengi,Baba Ahmed,Merzouk
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p. 1211 - 1213
(2007/10/03)
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- Restricted rotation about Nsp2-Csp3 bond through π-electronic interactions : A1H NMR study
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The electronic repulsion of a carboxyl group from a phenyl ring has been found to restrict rotation about Nsp2-Csp3 bond. A stable sp3-geometry of a carbon in N-CHR-COOH derivatives of a,β-(9,10-dihydroanthracene-9,10-diyl)succinimide has been demonstrated on the basis of shielding parameters of N′-alkyls. The carboxyl group does not exhibit hydrogen bonding with the carbonyls of the succinimide and remains in anti orientation. Though the anisotropic effect of an olefinic bond is fairly small, the interaction of carboxyl group with the olefinic bond is evident in CPD-MA adduct derivative.
- Singh, Kalpana,Srivastava, Nishi,Verma, Shiva M.
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p. 142 - 145
(2007/10/03)
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- DESIGN AND SYNTHETIC APPLICATIONS OF NEW HETEROMETALLACYCLES
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The reaction of cyclic anhydrides with Ni(0) complexes lead to the formation of nickelacycles by oxidative addition followed by decarbonylation.The preparation of chiral nickelacycles from anhydrides derived from amino acids and their reactivity is described.The formation of new heteropalladacycles by C-H activation or transmetallation reactions and their reactivity will be also discussed.
- Echavarren, Antonio M.,Cardenas, Diego J.,Castano, Ana M.,Cuerva, Juan M.,Mateo, Cristina
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p. 549 - 558
(2007/10/02)
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- SULFUR YLIDES. 3. SYNTHESIS OF KETO-GROUP STABILIZED AMINO-CONTAINING SULFUR YLIDES FROM AMINO ACIDS
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An effective path of synthesis was developed of new synthetic intermediates, the optically active, keto-group stabilized amino-substituted sulfur ylides.
- Tolstikov, G. A.,Galin, F. Z.,Lakeev, S. N.,Khalilov, L. M.,Sultanova, V. S.
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p. 535 - 541
(2007/10/02)
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- Regioselective functionalization of chiral nickelacycles derived from N-protected aspartic and glutamic anhydrides
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The electrophilic cleavage of the nickelacycles resulting from oxidative addition of Ni(o) complexes to N-protected aspartic and glutamic anhydrides, followed by decarbonylation, gives rise regioselectively to derivatives of α- and β-alanine or α- and γ-aminobutyric acid, respectively.
- Castano,Echavarren
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p. 4783 - 4786
(2007/10/02)
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- Reagents and synthetic methods. 20: Reaction of diphenylphosphorophthalimide with alkyl- or arylamines. Synthesis of N-substituted phthalimides
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Some N-substituted phthalimides are obtained from alkyl or arylamines by means of diphenyl phosphorophthalimide.A possible mechanism for that conversion is briefly discussed.
- Andres, Jose Angel,Palomo, Claudio
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p. 369 - 371
(2007/10/02)
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