The Experts below are selected from a list of 198 Experts worldwide ranked by ideXlab platform
Ya Jiang Yang - One of the best experts on this subject based on the ideXlab platform.
-
formation mechanism of supramolecular hydrogels in the presence of l Phenylalanine Derivative as a hydrogelator
Journal of Colloid and Interface Science, 2007Co-Authors: Xin Jian Fu, Ning Xia Wang, Sheng Zu Zhang, Hong Wang, Ya Jiang YangAbstract:Abstract A novel chiral hydrogelator, l -Phenylalanine Derivative can self-assemble in aqueous media at different pH values to form supramolecular hydrogels. The images of the FE-SEM indicate that different aggregates of TC18PheBu in morphology were formed, which further lead to the formation of spherical crystallites as observed by polarized optical microscope (POM). The FT-IR spectra of the supramolecular hydrogels reveal that intermolecular hydrogen-bonding and hydrophobic interactions are the driving forces for the self-assembly of TC18PheBu. Fluorescence spectra of TC18PheBu in aqueous solutions in the presence of pyrene as a probe further confirm the importance of hydrophobic interactions for the self-assembly. The circular dichroism (CD) spectra of TC18PheBu in supramolecular hydrogels in the presence of KF indicate that the hydrogen-bonding interaction can be disrupted by fluoride ions, which further confirm the importance of hydrogen bonding for the self-assembly of TC18PheBu.
-
Effect of hydrogen bonding and hydrophobic interaction on the formation of supramolecular hydrogels formed by l-Phenylalanine Derivative hydrogelator
Chinese Chemical Letters, 2007Co-Authors: Xin Jian Fu, Ning Xia Wang, Sheng Zu Zhang, Hong Wang, Ya Jiang YangAbstract:Abstract A new hydrogelator, pyridinium bromide salt of N -6-bromohexanoyl- l -phenylamino octadecane, was synthesized. Supramolecular hydrogels can be formed through the self-assembly of this hydrogelator in water. In this work, D 2 O was used instead of H 2 O as solvent for FT-IR measurement due to the fact that it is impossible to obtain useful FT-IR information on the hydrogen bonding in water. The investigation of FT-IR and steady-state fluorescence indicated that the driving forces for the self-assembly were mainly hydrogen bonding and hydrophobic interaction. Based on the data of XRD and molecular modeling, the possible mechanism of the formation of hydrogelator aggregates was proposed.
Yasushi Arano - One of the best experts on this subject based on the ideXlab platform.
-
novel 18f labeled α methyl Phenylalanine Derivative with high tumor accumulation and ideal pharmacokinetics for tumor specific imaging
Molecular Pharmaceutics, 2019Co-Authors: Hirofumi Hanaoka, Yasushi Arano, Hiroyuki Suzuki, Yasuhiro Ohshima, Aiko Yamaguchi, Noriko S Ishioka, Tetsuya Higuchi, Yoshito TsushimaAbstract:Positron emission tomography (PET) imaging with 18F-labeled α-methyl-substituted amino acids exerts significant influence on differential diagnosis of malignant tumors and tumor-like lesions. Exclu...
-
facile synthesis and evaluation of c functionalized benzyl 1 oxa 4 7 10 triazacyclododecane n n n triacetic acid as chelating agent for in labeled polypeptides
Bioorganic & Medicinal Chemistry, 2012Co-Authors: Hiroyuki Suzuki, Ayaka Kanai, Tomoya Uehara, Hirofumi Hanaoka, Francisco Guerra L Gomez, Yasushi AranoAbstract:Abstract A 12-membered polyazamacrocycle, 1-oxa-4,7,10-triazacyclododecane-N,N′,N″-triacetic acid (ODTA), has been reported to provide an indium chelate of net neutral charge with thermodynamic stability higher than 1,4,7,10-tetraazacyclododecane-N,N′,N″,N‴-tetraacetic acid (DOTA). However, neither synthetic procedure for a C-functionalized ODTA (C-ODTA) nor its chelating ability with a trace amount of radioactive indium-111 (111In) has been elucidated. We herein present a facile synthetic procedure for C-ODTA, and estimated its ability as a chelating agent for radiolabeling peptides and proteins with 111In. The synthetic procedure involves the synthesis of a linear precursor using a para-substituted Phenylalanine Derivative as a starting material. The following intramolecular cyclization reaction was best performed (>73% yield) when Boc-protected linear compound and the condensation reagent, HATU, were simultaneously added to the reaction vessel at the same flow rate. The cyclic compound was then reduced with BH3 and alkylated with tert-butyl bromoacetate. The synthetic procedure was straightforward and some optimization would be required. However, most of the intermediate compounds were obtained easily in good yields, suggesting that the present synthetic procedure would be useful to synthesize C-ODTA Derivatives. The intramolecular cyclization reaction might also be applicable to synthesize polyazamacrocycles of different ring sizes and cyclic peptides. In 111In radiolabeling reactions, C-ODTA provided 111In chelates in higher radiochemical yields at low ligand concentrations when compared with C-DOTA. The 111In-labeled C-ODTA remained unchanged in the presence of apo-transferrin. The biodistribution studies also showed that the 111In-labeled compound was mainly excreted into urine as intact. These findings indicate that C-ODTA would be useful to prepare 111In-labeled peptides of high specific activities in high radiochemical yields.
-
Facile synthesis and evaluation of C-functionalized benzyl-1-oxa-4,7,10-triazacyclododecane-N,N',N″-triacetic acid as chelating agent for ¹¹¹In-labeled polypeptides.
Bioorganic & Medicinal Chemistry, 2011Co-Authors: Hiroyuki Suzuki, Ayaka Kanai, Francisco L. Guerra Gomez, Tomoya Uehara, Hirofumi Hanaoka, Yasushi AranoAbstract:Abstract A 12-membered polyazamacrocycle, 1-oxa-4,7,10-triazacyclododecane-N,N′,N″-triacetic acid (ODTA), has been reported to provide an indium chelate of net neutral charge with thermodynamic stability higher than 1,4,7,10-tetraazacyclododecane-N,N′,N″,N‴-tetraacetic acid (DOTA). However, neither synthetic procedure for a C-functionalized ODTA (C-ODTA) nor its chelating ability with a trace amount of radioactive indium-111 (111In) has been elucidated. We herein present a facile synthetic procedure for C-ODTA, and estimated its ability as a chelating agent for radiolabeling peptides and proteins with 111In. The synthetic procedure involves the synthesis of a linear precursor using a para-substituted Phenylalanine Derivative as a starting material. The following intramolecular cyclization reaction was best performed (>73% yield) when Boc-protected linear compound and the condensation reagent, HATU, were simultaneously added to the reaction vessel at the same flow rate. The cyclic compound was then reduced with BH3 and alkylated with tert-butyl bromoacetate. The synthetic procedure was straightforward and some optimization would be required. However, most of the intermediate compounds were obtained easily in good yields, suggesting that the present synthetic procedure would be useful to synthesize C-ODTA Derivatives. The intramolecular cyclization reaction might also be applicable to synthesize polyazamacrocycles of different ring sizes and cyclic peptides. In 111In radiolabeling reactions, C-ODTA provided 111In chelates in higher radiochemical yields at low ligand concentrations when compared with C-DOTA. The 111In-labeled C-ODTA remained unchanged in the presence of apo-transferrin. The biodistribution studies also showed that the 111In-labeled compound was mainly excreted into urine as intact. These findings indicate that C-ODTA would be useful to prepare 111In-labeled peptides of high specific activities in high radiochemical yields.
Andrew R. Barron - One of the best experts on this subject based on the ideXlab platform.
-
fullerene derivatized amino acids synthesis characterization antioxidant properties and solid phase peptide synthesis
Chemistry: A European Journal, 2007Co-Authors: Jianzhong Yang, Lawrence B Alemany, Jonathan W Driver, Jeffrey D Hartgerink, Andrew R. BarronAbstract:A series of [60]fullerene-substituted Phenylalanine (Baa) and lysine Derivatives have been prepared by the condensation of 1,2-(4'-oxocyclohexano)fullerene with the appropriately protected (4-amino)Phenylalanine and lysine, respectively. Conversion of the imine to the corresponding amine is achieved by di-acid catalyzed hydroboration. The reduction of the imine is not accompanied by hydroboration of the fullerene cage. The [70]fullerene Phenylalanine Derivative has also been prepared as have the di-amino acid Derivatives. The compounds were characterized by MALDI-TOF mass spectrometry, UV/Vis spectroscopy, and cyclic voltammetry. 1 H and 13 C NMR spectroscopy allowed the observation of diastereomers. Fullerene-substituted peptides may be synthesized on relatively large scale by solid-phase peptide synthesis. The presence of the C 60 -substituted amino acid in a peptide has a significant effect on the secondary structures and self-assembly properties of peptides as compared to the native peptide. The antioxidant assay of Baa and a Baa-derived anionic peptide was determined to be significantly more potent than Trolox.
-
The use of fullerene substituted Phenylalanine amino acid as a passport for peptides through cell membranes
Organic and Biomolecular Chemistry, 2007Co-Authors: Jianzhong Yang, Jonathan Driver, Kuan Wang, Jianhua Yang, Andrew R. BarronAbstract:We report the formation of a fullerene-peptide conjugate via the incorporation of a fullerene substituted Phenylalanine Derivative, "Bucky amino acid" (Baa), to a cationic peptide, which acts as a passport for intracellular delivery, enabling transport of a range of sequences into HEK-293, HepG2, and neuroblastoma cells where the peptides in the absence of the fullerene amino acid cannot enter the cell. Delivery of the fullerene species to either the cytoplasm or nucleus of the cell is demonstrated. Fullerene peptides based on the nuclear localization sequence (NLS), H-Baa-Lys(FITC)-Lys-Lys-Arg-Lys-Val-OH, can actively cross over the cell membrane and accumulate significantly around the nucleus of HEK-293 and neuroblastoma cells, while H-Baa-Lys(FITC)-Lys8-OH accumulates in the cytoplasm. Cellular studies show that the uptake for the anionic peptide Baa-Lys(FITC)Glu4Gly3Ser-OH is greatly reduced in comparison with the cationic fullerene peptides of the same concentration. The hydrophobic nature of the fullerene assisting peptide transport is suggested by the effect of gamma-cyclodextrin (CD) in lowering the efficacy of transport. These data suggest that the incorporation of a fullerene-based amino acid provides a route for the intracellular delivery of peptides and as a consequence the creation of a new class of cell penetrating peptides.
Richard J. Payne - One of the best experts on this subject based on the ideXlab platform.
-
Synthesis of β-Thiol Phenylalanine for Applications in One-Pot Ligation-Desulfurization Chemistry.
Organic Letters, 2015Co-Authors: Lara R. Malins, Andrew M. Giltrap, Luke J. Dowman, Richard J. PayneAbstract:The efficient synthesis of a β-thiol Phenylalanine Derivative is described starting from Garner’s aldehyde. The utility of this amino acid in peptide ligation–desulfurization chemistry is described, including the trifluoroethanethiol (TFET)-promoted one-pot assembly of the 62 residue peptide hormone augurin.
-
Synthesis and Utility of β-Selenol-Phenylalanine for Native Chemical Ligation–Deselenization Chemistry
Organic Letters, 2012Co-Authors: Lara R. Malins, Richard J. PayneAbstract:An efficient synthetic route to a suitably protected β-selenol-Phenylalanine Derivative from commercially available Garner’s aldehyde is described. The incorporation of this building block into peptides and its application in native chemical ligation reactions with peptide thioesters are demonstrated. Ligation products were chemoselectively deselenized (including in the presence of unprotected cysteine residues) to provide native peptides.
-
synthesis and utility of β selenol Phenylalanine for native chemical ligation deselenization chemistry
Organic Letters, 2012Co-Authors: Lara R. Malins, Richard J. PayneAbstract:An efficient synthetic route to a suitably protected β-selenol-Phenylalanine Derivative from commercially available Garner’s aldehyde is described. The incorporation of this building block into peptides and its application in native chemical ligation reactions with peptide thioesters are demonstrated. Ligation products were chemoselectively deselenized (including in the presence of unprotected cysteine residues) to provide native peptides.
Hiroyuki Suzuki - One of the best experts on this subject based on the ideXlab platform.
-
novel 18f labeled α methyl Phenylalanine Derivative with high tumor accumulation and ideal pharmacokinetics for tumor specific imaging
Molecular Pharmaceutics, 2019Co-Authors: Hirofumi Hanaoka, Yasushi Arano, Hiroyuki Suzuki, Yasuhiro Ohshima, Aiko Yamaguchi, Noriko S Ishioka, Tetsuya Higuchi, Yoshito TsushimaAbstract:Positron emission tomography (PET) imaging with 18F-labeled α-methyl-substituted amino acids exerts significant influence on differential diagnosis of malignant tumors and tumor-like lesions. Exclu...
-
facile synthesis and evaluation of c functionalized benzyl 1 oxa 4 7 10 triazacyclododecane n n n triacetic acid as chelating agent for in labeled polypeptides
Bioorganic & Medicinal Chemistry, 2012Co-Authors: Hiroyuki Suzuki, Ayaka Kanai, Tomoya Uehara, Hirofumi Hanaoka, Francisco Guerra L Gomez, Yasushi AranoAbstract:Abstract A 12-membered polyazamacrocycle, 1-oxa-4,7,10-triazacyclododecane-N,N′,N″-triacetic acid (ODTA), has been reported to provide an indium chelate of net neutral charge with thermodynamic stability higher than 1,4,7,10-tetraazacyclododecane-N,N′,N″,N‴-tetraacetic acid (DOTA). However, neither synthetic procedure for a C-functionalized ODTA (C-ODTA) nor its chelating ability with a trace amount of radioactive indium-111 (111In) has been elucidated. We herein present a facile synthetic procedure for C-ODTA, and estimated its ability as a chelating agent for radiolabeling peptides and proteins with 111In. The synthetic procedure involves the synthesis of a linear precursor using a para-substituted Phenylalanine Derivative as a starting material. The following intramolecular cyclization reaction was best performed (>73% yield) when Boc-protected linear compound and the condensation reagent, HATU, were simultaneously added to the reaction vessel at the same flow rate. The cyclic compound was then reduced with BH3 and alkylated with tert-butyl bromoacetate. The synthetic procedure was straightforward and some optimization would be required. However, most of the intermediate compounds were obtained easily in good yields, suggesting that the present synthetic procedure would be useful to synthesize C-ODTA Derivatives. The intramolecular cyclization reaction might also be applicable to synthesize polyazamacrocycles of different ring sizes and cyclic peptides. In 111In radiolabeling reactions, C-ODTA provided 111In chelates in higher radiochemical yields at low ligand concentrations when compared with C-DOTA. The 111In-labeled C-ODTA remained unchanged in the presence of apo-transferrin. The biodistribution studies also showed that the 111In-labeled compound was mainly excreted into urine as intact. These findings indicate that C-ODTA would be useful to prepare 111In-labeled peptides of high specific activities in high radiochemical yields.
-
Facile synthesis and evaluation of C-functionalized benzyl-1-oxa-4,7,10-triazacyclododecane-N,N',N″-triacetic acid as chelating agent for ¹¹¹In-labeled polypeptides.
Bioorganic & Medicinal Chemistry, 2011Co-Authors: Hiroyuki Suzuki, Ayaka Kanai, Francisco L. Guerra Gomez, Tomoya Uehara, Hirofumi Hanaoka, Yasushi AranoAbstract:Abstract A 12-membered polyazamacrocycle, 1-oxa-4,7,10-triazacyclododecane-N,N′,N″-triacetic acid (ODTA), has been reported to provide an indium chelate of net neutral charge with thermodynamic stability higher than 1,4,7,10-tetraazacyclododecane-N,N′,N″,N‴-tetraacetic acid (DOTA). However, neither synthetic procedure for a C-functionalized ODTA (C-ODTA) nor its chelating ability with a trace amount of radioactive indium-111 (111In) has been elucidated. We herein present a facile synthetic procedure for C-ODTA, and estimated its ability as a chelating agent for radiolabeling peptides and proteins with 111In. The synthetic procedure involves the synthesis of a linear precursor using a para-substituted Phenylalanine Derivative as a starting material. The following intramolecular cyclization reaction was best performed (>73% yield) when Boc-protected linear compound and the condensation reagent, HATU, were simultaneously added to the reaction vessel at the same flow rate. The cyclic compound was then reduced with BH3 and alkylated with tert-butyl bromoacetate. The synthetic procedure was straightforward and some optimization would be required. However, most of the intermediate compounds were obtained easily in good yields, suggesting that the present synthetic procedure would be useful to synthesize C-ODTA Derivatives. The intramolecular cyclization reaction might also be applicable to synthesize polyazamacrocycles of different ring sizes and cyclic peptides. In 111In radiolabeling reactions, C-ODTA provided 111In chelates in higher radiochemical yields at low ligand concentrations when compared with C-DOTA. The 111In-labeled C-ODTA remained unchanged in the presence of apo-transferrin. The biodistribution studies also showed that the 111In-labeled compound was mainly excreted into urine as intact. These findings indicate that C-ODTA would be useful to prepare 111In-labeled peptides of high specific activities in high radiochemical yields.