- N-transfer reagent and method for preparing the same and its application
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Provided are a novel N-transfer reagent and a method for preparing the same and its application. The N-transfer reagent is represented by the following Formula (I): The various novel N-transfer reagents of the present invention can be quickly prepared by employing different nitrobenzene precursors. The N-transfer reagents can directly convert a variety of amino compounds into diazo compounds under mild conditions. Particularly, the N-transfer reagents can facilitate the synthesis of the diazo compounds. The application of synthesizing diazo compounds of the present invention can greatly decrease the difficulty in operation, increase the safety during experiments, reduce the cost of production and the environmental pollution, and enhance the industrial value of diazo compounds.
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Page/Page column 24; 49-50; 53-54; 57-58
(2021/06/25)
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- The tandem chain extension aldol reaction used for synthesis of ketomethylene tripeptidomimetics targeting hPEPT1
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The rationale for targeting the human di-/tripeptide transporter hPEPT1 for oral drug delivery has been well established by several drug and prodrug cases. The aim of this study was to synthesize novel ketomethylene modified tripeptidomimetics and to investigate their binding affinity for hPEPT1. Three related tripeptidomimetics of the structure H-Phe-ψ[COCH2]- Ser(Bz)-Xaa-OH were synthesized applying the tandem chain extension aldol reaction, where amino acid derived β-keto imides were stereoselectively converted to α-substituted γ-keto imides. In addition, three corresponding tripeptides, composed of amide bonds, were synthesized for comparison of binding affinities. The six investigated compounds were all defined as high affinity ligands (Ki-values 14C]Gly-Sar uptake in Caco-2 cells. Consequently, the ketomethylene replacement for the natural amide bond and α-side chain modifications appears to offer a promising strategy to modify tripeptidic structures while maintaining a high affinity for hPEPT1.
- Thorn, Karina,Nielsen, Carsten Uhd,Jakobsen, Palle,Steffansen, Bente,Zercher, Charles K.,Begtrup, Mikael
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supporting information; experimental part
p. 4597 - 4601
(2011/09/12)
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- Serine and threonine Schiff base esters react with β-anomeric peracetates in the presence of BF3·Et2O to produce β-glycosides
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Improved procedures are reported for the glycosylation of L-serine and L-threonine utilizing activated Schiff base glycosyl acceptors, which are less expensive and more efficient alternatives to published methods. L-serine or L-threonine benzyl ester hydrochloride salts were reacted with the diarylketimine bis-(4-methoxyphenyl)-methanimine in CH3CN at rt to form the more nucleophilic Schiff bases 3a and 3b in excellent yield. These Schiff bases exhibited ring-chain tautomerism in CDCl3 as shown by 1H NMR. Schiff bases 3a and 3b, acting as glycosyl acceptors, reacted at rt with simple sugar peracetate donors with BF3·OEt 2 promotion to provide the corresponding L-serine and L-threonine O-linked glycosides in excellent yields and purities. The dipeptide ester Schiff base Ar2C = N-Ser-Val-OCH3 3e also reacted to provide β-glycosides in excellent yields, and without epimerization. With microwave irradiation the reactions were complete in 2 to 5 min. To investigate this reaction further, classical AgOTf-promoted Koenigs-Knorr reaction of D-glucopyranosyl, lactosyl, and maltosyl bromides were examined, providing the β-glycosides with yields ranging from 35% to 68%. The difference in reactivity between α- and β-carbohydrate peracetate donors was remarkable. The less configurationally stable D-xylopyranosyl tetra-acetate (a pentose) showed no selectivity (αvsβ-configuration) toward the Schiff bases. Copyright Taylor & Francis Group, LLC.
- Keyari, Charles M.,Polt, Robin
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experimental part
p. 181 - 206
(2011/04/23)
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- A class of novel carboline intercalators: Their synthesis, in vitro anti-proliferation, in vivo anti-tumor action, and 3D QSAR analysis
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Based on DOCK scores 18 N-(3-benzyloxycarbonylcarboline-1-yl)ethylamino acid benzylesters (6a-r) were synthesized as anti-tumor agents. Their IC 50 values against five human carcinoma cell lines ranged from 11.1 μM to more than 100 μM. The in vivo assay identified five derivatives of them had no anti-tumor action, the anti-tumor activity of nine derivatives of them equaled that of cytarabine, and the anti-tumor activity of three derivatives of them was higher than that of cytarabine. The UV and fluorescence spectra, as well as the relative viscosity and melting temperature measurements of calf thymus DNA (CT DNA) with and without the representative compound suggested that DNA intercalation could be their action mechanism. The 3D QSAR analysis of N-(3-benzyloxycarbonylcarboline-1-yl)ethylamino acid benzylesters (6a-r) revealed that their in vivo anti-tumor activity significantly depends on the molecular electrostatic and steric fields of the side chain of the amino acid residue.
- Wu, Jianhui,Li, Chunyu,Zhao, Ming,Wang, Wenjing,Wang, Yuji,Peng, Shiqi
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experimental part
p. 6220 - 6229
(2010/10/04)
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- IMPROVED METHOD FOR MAKING AMINO ACID CLYCOSIDES AND GLYCOPEPTIDES
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The invention relates to an improved method of preparing amino glycosides and glycopeptides. The method involves reacting an diarylketimine with an amino acid having a hydroxal side chain to produce an imino-bound intermediate compound. This intermediate is then reacted with an acetylated sugar residue under suitable conditions to yield amino glycoside. The synthetic amino glycoside may be incorporated into a peptide chain under conditions compatible with standard glycopeptide synthesis reactions.
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Page/Page column 8-9
(2010/11/27)
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- Antibacterial agents
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A compound represented by formula I: STR1 is disclosed. The compounds are active primarily against gram negative organisms. Pharmaceutical compositions and methods of treatment are also disclosed.
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