- Optimized syntheses of Fmoc azido amino acids for the preparation of azidopeptides
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The rise of CuI-catalyzed click chemistry has initiated an increased demand for azido and alkyne derivatives of amino acid as precursors for the synthesis of clicked peptides. However, the use of azido and alkyne amino acids in peptide chemistry is complicated by their high cost. For this reason, we investigated the possibility of the in-house preparation of a set of five Fmoc azido amino acids: β-azido l-alanine and d-alanine, γ-azido l-homoalanine, δ-azido l-ornithine and ω-azido l-lysine. We investigated several reaction pathways described in the literature, suggested several improvements and proposed several alternative routes for the synthesis of these compounds in high purity. Here, we demonstrate that multigram quantities of these Fmoc azido amino acids can be prepared within a week or two and at user-friendly costs. We also incorporated these azido amino acids into several model tripeptides, and we observed the formation of a new elimination product of the azido moiety upon conditions of prolonged couplings with 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate/DIPEA. We hope that our detailed synthetic protocols will inspire some peptide chemists to prepare these Fmoc azido acids in their laboratories and will assist them in avoiding the too extensive costs of azidopeptide syntheses. Experimental procedures and/or analytical data for compounds 3–5, 20, 25, 26, 30 and 43–47 are provided in the supporting information.
- Pícha, Jan,Budě?ínsky, Milo?,Machá?ková, Kate?ina,Collinsová, Michaela,Jirá?ek, Ji?í
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p. 202 - 214
(2017/04/06)
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- PROPYL CATIONIC PEPTIDE LIPIDS, SYNTHESIS METHOD THEREOF, AND APPLICATION THEREOF
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A class of propyl cationic peptide lipids is propyl cationic peptide lipid compounds having a general formula structure as follows. After the propyl cationic peptide lipids are dispersed in water, a cationic liposome with a particle size of approximately 100 nm is obtained. The cationic liposome can carry plasmid DNA (pDNA) or small interfering RNA (siRNA) into cells to realize the function of gene delivery, and is almost non-toxic to the cells.
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- Caged xanthones: Potent inhibitors of global predominant MRSA USA300
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Total of 22 caged xanthones were subjected to susceptibility testing of global epidemic MRSA USA300. Natural morellic acid showed the strongest potency (MIC of 12.5 μM). However, its potent toxicity diminishes MRSA therapeutic potential. We synthetically modified natural morellic acid to yield 13 derivatives (3a-3m). Synthetically modified 3b retained strong potency in MRSA growth inhibition, yet the toxicity was 20-fold less than natural morellic acid, permitting the possibility of using caged xanthones for MRSA therapeutic.
- Chaiyakunvat, Pongkorn,Anantachoke, Natthinee,Reutrakul, Vichai,Jiarpinitnun, Chutima
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supporting information
p. 2980 - 2983
(2016/06/13)
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- Mild oxidative cleavage of 9-BBN-protected amino acid derivatives
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Protection of the amino acid moiety using 9-BBN is an effective method to enable side chain manipulations in synthesis of complex amino acids. We investigated the standard, mild method for deprotection of the 9-BBN group in methanolic chloroform, and found that it relies on a slow oxidation mediated by molecular oxygen. Building on this insight, we have developed a method that allows for a fast and selective deprotection using simple peroxy acid reagents. After Fmoc protection, products were isolated in >90% yield for a series of amino acid derivatives, including a galactosylated derivative of hydroxylysine. A representative set of 9-BBN-protected amino acid derivatives were efficiently deprotected using peracid reagents in excellent yields. Deprotection is orthogonal with several common protecting groups. Its tolerance of highly acid sensitive groups, such as trityl-protected amides and glycosidic linkages, is especially notable.
- Ankner, Tobias,Norberg, Thomas,Kihlberg, Jan
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p. 3767 - 3770
(2015/06/16)
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- Tri-peptide cationic lipids for gene delivery
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Several novel tri-peptide cationic lipids were designed and synthesized for delivering DNA and siRNA. They have tri-lysine and tri-ornithine as headgroups, a carbamate group as a linker and 12 and 14 carbon atom alkyl groups as tails. These tri-peptide cationic lipids were prepared into cationic liposomes for the study of the physicochemical properties and gene delivery. Their particle size, zeta potential and DNA-binding were characterized to show that they were suitable for gene transfection. Further results indicate that these lipids can transfer DNA and siRNA very efficiently into NCI-H460 and Hep-2 tumor cells. The selected lipid, CDO14, was able to deliver combined siRNAs against c-Myc and VEGF for silencing distinct oncogenic pathways in lung tumors of mice, with little in vitro and in vivo toxicity. This journal is
- Zhao, Yinan,Zhang, Shubiao,Zhang, Yuan,Cui, Shaohui,Chen, Huiying,Zhi, Defu,Zhen, Yuhong,Zhang, Shufen,Huang, Leaf
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p. 119 - 126
(2015/02/19)
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- A one-pot procedure for the preparation of N-9-fluorenylmethyloxycarbonyl- α-amino diazoketones from α-amino acids
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The study describes a new "one-pot" route to the synthesis of N-9-fluorenylmethyloxycarbonyl (Fmoc) α-amino diazoketones. The procedure was tested on a series of commercially available free or side-chain protected α-amino acids employed as precursors. The conversion into the title compounds was achieved by masking and activating the α-amino acids with a single reagent, namely, 9-fluorenylmethyl chloroformate (Fmoc-Cl). The resulting N-protected mixed anhydrides were reacted with diazomethane to lead to the α-amino diazoketones, which were isolated by flash column chromatography in very good to excellent overall yields. The versatility of the procedure was verified on lipophilic α-amino acids and further demonstrated by the preparation of N-Fmoc-α-amino diazoketones also from α-amino acids containing side-chain masking groups, which are orthogonal to the Fmoc one. The results confirmed that tert-butyloxycarbonyl (Boc), tert-butyl (tBu), and 2,2,4,6,7-pentamethyldihydrobenzofuran-5-sulfonyl (Pbf), three acid-labile protecting groups mostly adopted in the solution and solid-phase peptide synthesis, are compatible to the adopted reaction conditions. In all cases, the formation of the corresponding C-methyl ester of the starting amino acid was not observed. Moreover, the proposed method respects the chirality of the starting α-amino acids. No racemization occurred when the procedure was applied to the synthesis of the respective N-Fmoc-protected α-amino diazoketones from l-isoleucine and l-threonine and to the preparation of a diastereomeric pair of N-Fmoc-protected dipeptidyl diazoketones.
- Siciliano, Carlo,De Marco, Rosaria,Guidi, Ludovica Evelin,Spinella, Mariagiovanna,Liguori, Angelo
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p. 10575 - 10582
(2013/02/22)
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- Derivates of Polyethylene Glycol Modified Thymosin Alpha 1
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Pharmaceutical compositions that include thymosin alpha 1 peptide derivatives modified at the C-terminal of the peptide chain with polyethylene glycol, and their pharmaceutical acceptable salts, are generally disclosed. Also, new methods used to prepare these thymosin alpha 1 peptide derivatives modified at the C-terminal of the peptide chain with polyethylene glycol are generally provided. The presently disclosed compounds and their salts can be prepared administered to humans to treat immune disease and can also be used in adjuvant treatment.
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- A novel and efficient method for cleavage of phenacylesters by magnesium reduction with acetic acid
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(Equation Presented) In the present study, we use magnesium turnings as a new deprotection reagent for the phenacyl group during orthogonal organic synthesis in the presence of other esters and sensitive protecting groups. By applying the new magnesium turnings/acetic acid deprotection method, phenacyl group can be more easily combined with other protecting groups that are not compatible with the zinc/acetic acid method.
- Kokinaki, Stella,Leondiadis, Leondios,Ferderigos, Nikolas
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p. 1723 - 1724
(2007/10/03)
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- GLP-2 compounds, formulations, and uses thereof
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The present invention relates to novel human glucagon-like peptide-2 (GLP-2) peptides and human glucagon-like peptide-2 derivatives which have a protracted profile of action as well as polynucleotide constructs encoding such peptides, vectors and host cells comprising and expressing the polynucleotide, pharmaceutical compositions, uses and methods of treatment.
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- Dual linker with a reference cleavage site for information rich analysis of polymer-supported transformations
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Two dual linker systems with specific reference cleavage sites were designed and synthesized to accelerate and simplify development and optimization of reaction conditions for solid-phase synthesis. The dual linker allows simple evaluation of cleavage rate of polymer-supported compounds from the linker and, at the same time, ensures that all resin-bound components are cleaved from the solid support. The dual linker 4 was assembled from two Wang linkers connected by a three carbon spacer. The linker 9 was synthesized using the PAL and HMPB linkers.
- Krchňák, Viktor,Slough, Greg A.
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p. 5237 - 5241
(2007/10/03)
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- A large scale synthesis of mono- and di-urethane derivatives of lysine
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In the search for a practical route to lysine diurethane derivatives useful for peptide synthesis, we elaborated the synthesis of N(ε)-tert- butoxycarbonyl-L-lysine copper(II) complex (1). This served as substrate for obtaining N(ε)-tert-butoxycarbonyl-L-lysine (2), N(α)-benzyloxycarbonyl- N(ε)-tert-butoxycarbonyl-L-lysine dicyclohexylamine salt (3) and N(α)-(9- fluorenyl)methoxycarbonyl-N(ε)-tert-butoxycarbonyl-L-lysine (4).
- Wiejak, Stanislaw,Masiukiewicz, Elzbieta,Rzeszotarska, Barbara
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p. 1489 - 1490
(2007/10/03)
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- Apparatus and methods for detecting antibodies
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A single, unitary, solid phase support apparatus having a planar surface divided into a plurality of separate zone functions to detect antibodies. Each zone has bonded to it, a different peptide through its C-terminal end. The zones are incubated with the analyte sample and observed for reaction, indicating the virus-specific or bacteria specific presence or absence.
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- A New Synthesis of Thymosin α1
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Thymosin α1, an N-acetylated octacosa thymus peptide, isolated first from thymosin fraction 5, is synthesized by the solid phase method using the p-benzyloxybenzyl alcohol/polystyrene/divinylbenzene resin, Nα-Fmoc-amino acids and those with tert-butyl or Boc side chain protection.All couplings are performed with the Bop reagent.The peptide is purified by a combination of gel chromatography and preparative HPLC, its purity checked by amino acid analysis and analytical HPLC, and the biological activity tested by the E-rosette assay.
- Echner, Hartmut,Voelter, Wolfgang
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p. 1095 - 1098
(2007/10/02)
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