2224-52-4Relevant articles and documents
Ring opening polymerization of α-amino acid N-carboxyanhydrides catalyzed by rare earth catalysts: Polymerization characteristics and mechanism
Peng, Hui,Ling, Jun,Shen, Zhiquan
, p. 1076 - 1085 (2012)
Five rare earth complexes are first introduced to catalyze ring opening polymerizations (ROPs) of γ-benzyl-L-glutamate N-carboxyanhydride (BLG NCA) and L-alanine NCA (ALA NCA) including rare earth isopropoxide (RE(OiPr)3), rare earth tris(2,6-di-tert-butyl-4-methylphenolate) (RE(OAr)3), rare earth tris(borohydride) (RE(BH4) 3(THF)3), rare earth tris[bis(trimethylsilyl)amide] (RE(NTMS)3), and rare earth trifluoromethanesulfonate. The first four catalysts exhibit high activities in ROPs producing polypeptides with quantitative yields (>90%) and moderate molecular weight (MW) distributions ranging from 1.2 to 1.6. In RE(BH4)3(THF)3 and RE(NTMS)3 catalytic systems, MWs of the produced polypeptides can be controlled by feeding ratios of monomer to catalyst, which is in contrast to the systems of RE(OiPr)3 and RE(OAr)3 with little controllability over the MWs. End groups of the polypeptides are analyzed by MALDI-TOF MS and polymerization mechanisms are proposed accordingly. With ligands of significant steric hindrance in RE(OiPr)3 and RE(OAr) 3, deprotonation of 3-NH of NCA is the only initiation mode producing a N-rare earth metallated NCA (i) responsible for further chain growth, resulting in α-carboxylic-I-aminotelechelic polypeptides after termination. In the case of RE(BH4)3(THF)3 with small ligands, another initiation mode at 5-CO position of NCA takes place simultaneously, resulting in α-hydroxyl-I-aminotelechelic polypeptides. In RE(NTMS)3 system, the protonated ligand hexamethyldisilazane (HMDS) initiates the polymerization and produces α-amide-I-aminotelechelic polypeptides.
Effect of hydrophobic polypeptide length on performances of thermo-sensitive hydrogels
Han, Jiandong,Zhao, Xingyu,Xu, Weiguo,Wang, Wei,Han, Yuping,Feng, Xiangru
, (2018)
Thermosensitive gels are commonly used as drug carriers in medical fields, mainly due to their convenient processing and easy functionalization. However, their overall performance has been severely affected by their unsatisfying biocompatibility and biode
Self-assembly of a model peptide incorporating a hexa-histidine sequence attached to an Oligo-Alanine sequence, and binding to gold NTA/nickel nanoparticles
Hamley, Ian W.,Kirkham, Steven,Dehsorkhi, Ashkan,Castelletto, Valeria,Adamcik, Jozef,Mezzenga, Raffaele,Ruokolainen, Janne,Mazzuca, Claudia,Gatto, Emanuela,Venanzi, Mariano,Placidi, Ernesto,Bilalis, Panayiotis,Iatrou, Hermis
, p. 3412 - 3420 (2014)
Amyloid fibrils are formed by a model surfactant-like peptide (Ala)10-(His)6 containing a hexa-histidine tag. This peptide undergoes a remarkable two-step self-assembly process with two distinct critical aggregation concentrations (cac's), probed by fluorescence techniques. A micromolar range cac is ascribed to the formation of prefibrillar structures, whereas a millimolar range cac is associated with the formation of well-defined but more compact fibrils. We examine the labeling of these model tagged amyloid fibrils using Ni-NTA functionalized gold nanoparticles (Nanogold). Successful labeling is demonstrated via electron microscopy imaging. The specificity of tagging does not disrupt the β-sheet structure of the peptide fibrils. Binding of fibrils and Nanogold is found to influence the circular dichroism associated with the gold nanoparticle plasmon absorption band. These results highlight a new approach to the fabrication of functionalized amyloid fibrils and the creation of peptide/nanoparticle hybrid materials.
Pore-filled nanoporous silica colloidal films with enantioselective permeability
Ignacio-De Leon, Patricia A.,Cichelli, Julie A.,Abelow, Alexis E.,Zharov, Ilya
, p. 649 - 654 (2014)
We prepared nanoporous silica colloidal films whose nanopores were filled with polymer brushes containing chiral selector moieties in the side chains, or with a chiral polypeptide. Both types of polymers were grown inside the nanopores using surface-initiated polymerization and thus were covalently attached to the nanopore surface. We studied the enantioselective permeation in the resulting porefilled films and found that they possess a relatively high enantioselectivity. Increasing the number of chiral selectors inside the nanopores and preventing through solution diffusion by pore-filling with polymers did not lead to increased enantioselectivity compared to that observed for silica colloidal films whose nanopores were surfacemodified with a monolayer of chiral selectors. This suggests that the enantioselectivity depends solely on the energy difference between the enantiomer/selector complexes and that through solution diffusion plays a minor role in the transport of enantiomers, which occurs predominantly through site hopping.
Synthesis of α-Amino Acid N-Carboxyanhydrides
Laconde, Guillaume,Amblard, Muriel,Martinez, Jean
supporting information, p. 6412 - 6416 (2021/08/30)
A simple phosgene- and halogen-free method for synthesizing α-amino acid N-carboxyanhydrides (NCAs) is described. The reaction between Boc-protected α-amino acids and T3P reagent gave the corresponding NCA derivatives in good yield and purity with no detectable epimerization. The process is safe, is easy-to-operate, and does not require any specific installation. It generates nontoxic, easy to remove byproducts. It can apply to the preparation of NCAs for the on-demand on-site production of either little or large quantities.
METHOD OF SYNTHESIZING N-CARBOXYANHYDRIDE USING FLOW REACTOR
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Paragraph 0092-0096; 0119-0120, (2020/03/26)
PROBLEM TO BE SOLVED: To provide a synthesis method that allows high-yield continuous production of a compound of interest in synthesis and production of N-carboxyanhydride (NCA) and the like using a flow reactor. SOLUTION: In a synthesis method using a flow reactor 100, a basic solution adjusted in advance to a pH of 7-14 becomes acidic with a pH of 0-7, or an acidic solution adjusted in advance to a pH of 0-7 becomes basic with a pH of 7-14, within 60 seconds after the start of mixture of at least two ingredient solutions. SELECTED DRAWING: Figure 1 COPYRIGHT: (C)2020,JPOandINPIT
METHOD FOR PREPARATION OF N-CARBOXYANHYDRIDES
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Page/Page column 12; 14, (2020/05/12)
The invention discloses a method for the preparation off N-carboxyanhydrides (NCAs) by reaction of amino acids with phosgene.(II)
Capsidone artificial hapten, artificial antigen and preparation method and application thereof
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Paragraph 0080-0083; 0099-0103; 0116-0120, (2020/08/09)
The invention relates to the field of cathinone artificial antigen structures, and particularly relates to a cathinone artificial antigen, an artificial antigen as well as a preparation method and application thereof. The cathinone artificial antigen is characterized in that a molecular structural formula of the cathinone artificial antigen is shown as follows: the formula (1) is shown in the description. According to the cathinone artificial antigen provided by the invention, a connecting arm is introduced onto a site N of cathinone, and the connecting arm is introduced onto the decoration site so that a characteristic structure of the cathinone is kept to a maximum extent; moreover, the cathinone artificial antigen has an active group coupled with carrier protein and can be used as an antigen determinant group. Compared with an annular connecting arm, the connecting arm adopted by the invention is chain-shaped, an identification degree of T cells to the connecting arm can be reducedas much as possible during immunization, so that an antibody obtained by immunization has higher specificity and affinity to the cathinone.
Improved Scale-up Synthesis and Purification of Clinical Asthma Candidate MIDD0301
Arnold, Leggy A.,Cook, James M.,Knutson, Daniel E.,Mian, Md Yeunus,Roni, M. S. Rashid,Stafford, Douglas C.
, p. 1467 - 1476 (2020/11/23)
We report an improved and scalable synthesis of MIDD0301, a positive GABAA receptor modulator that is under development as oral and inhaled treatments for asthma. In contrast to other benzodiazepines in clinical use, MIDD0301 is a chiral compound that has limited brain absorption. The starting material to generate MIDD0301 is 2-amino-5-bromo-2′-fluorobenzophenone, which has a nonbasic nitrogen due to electron-withdrawing substituents in the ortho and para positions, reducing its reactivity toward activated carboxylic acids. Investigations of peptide coupling reagents on a multigram scale resulted in moderate yields due to incomplete conversions. Second, the basic conditions used for the formation of the seven-membered 1,4-diazepine ring resulted in racemization of the chiral center. We found that neutral conditions comparable to the pKa of the primary amine were sufficient to support the formation of the intramolecular imine but did not enable the simultaneous removal of the protecting group. Both difficulties were overcome with the application of the N-carboxyanhydride of d-alanine. Activated in the presence of an acid, this compound reacted with nonbasic 2-amino-5-bromo-2′-fluorobenzophenone and formed the 1,4-diazepine upon neutralization with triethylamine. Carefully designed workup procedures and divergent solubility of the synthesic intermediates in solvents and solvent combinations were utilized to eliminate the need for column chromatography. To improve compatibility with large-scale reactors, temperature-controlled slow addition of reagents generated the imidazodiazepine at -20 °C. All intermediates were isolated with a purity of >97% and impurities were identified and quantified. After the final hydrolysis step, MIDD0301 was isolated in a 44% overall yield and a purity of 98.9% after recrystallization. The enantiomeric excess was greater than 99.0%.
METHOD FOR PRODUCING AMINO ACID-N-CARBOXYLIC ACID ANHYDRIDE
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Paragraph 0081, (2020/08/07)
PROBLEM TO BE SOLVED: To provide: a method for safely and efficiently producing amino acid-N-carboxylic acid anhydride; and a method for producing peptide by using the obtained amino acid-N-carboxylic acid anhydride. SOLUTION: The method for producing an amino acid-N-carboxylic acid anhydride according to the present invention is characterized in that the amino acid-N-carboxylic acid anhydride is represented by the following formula (II), and a step of irradiating a composition containing a halogenated methane and an amino acid compound represented by the following formula (I) with high energy light in the presence of oxygen is included. [In the formula, R1 represents an amino acid side chain group in which the reactive group is protected, and R2 represents H or the like.]. SELECTED DRAWING: None COPYRIGHT: (C)2020,JPOandINPIT
