3958-60-9Relevant articles and documents
A photo-degradable injectable self-healing hydrogel based on star poly(ethylene glycol)-: B -polypeptide as a potential pharmaceuticals delivery carrier
Zhao, Dinglei,Tang, Quan,Zhou, Qiang,Peng, Kang,Yang, Haiyang,Zhang, Xingyuan
, p. 7420 - 7428 (2018)
As one of the most promising biomaterials, injectable self-healing hydrogels have found broad applications in a number of fields such as local drug delivery. However, controlled release of drugs in hydrogels is still difficult to realize up to now. Here, we report a novel photo-degradable injectable self-healing hydrogel based on the hydrophobic interaction of a biocompatible four-arms star polymer, poly(ethylene glycol)-b-poly(γ-o-nitrobenzyl-l-glutamate). The hydrophobic interaction between poly(γ-o-nitrobenzyl-l-glutamate) not only connects poly(ethylene glycol)-b-poly(γ-o-nitrobenzyl-l-glutamate) together with a crosslink but also provides a hydrophobic domain to encapsulate hydrophobic pharmaceuticals such as doxorubicin (DOX). Due to the dynamic character of the hydrophobic interaction, the hydrogel exhibits excellent injectable and self-healing ability. In particular, the photolabile o-nitribenzyl ester group is cleaved under UV irradiation. As a result, the hydrophobic domain transforms into the hydrophilic one and the embedded DOX is released effectively. An increasing release ratio of DOX dramatically enhances the apoptosis ratio of HeLa cells. We expect these attractive properties may be beneficial to practical applications of the hydrogel as an effective local drug delivery means in a truly physiological environment.
NovelN-transfer reagent for converting α-amino acid derivatives to α-diazo compounds
Lu, Guan-Han,Huang, Tzu-Chia,Hsueh, Hsiao-Chin,Yang, Shin-Cherng,Cho, Ting-Wei,Chou, Ho-Hsuan
supporting information, p. 4839 - 4842 (2021/05/25)
A novel universalN-transfer reagent for direct and effective transformation of α-amino ketones, acetamides, and esters to the corresponding α-diazo products under mild basic conditions has been developed. This one-step synthetic approach not only allows for generation of α-substituted-α-diazo carbonyl compounds from α-amino acid derivatives but also permits preparation of α-diazo dipeptides fromN-terminal dipeptides (32 examples, up to 91%).
Ethylene homo- and copolymerization catalyzed by vanadium, zirconium, and titanium complexes having potentially tridentate Schiff base ligands
Bia?ek, Marzena,Fryga, Julia,Hajdasz, Natalia,Matsko, Mikhail A.,Spaleniak, Grzegorz
, p. 184 - 194 (2021/07/09)
New potentially tridentate Schiff base ligands, 2-[({4-[(3-N,N-dimethylamino)propyl] phenyl}imino)methyl]-4,6-di-tert-butylphenol (L1H) and 2-[{2-(N-phenyl-N-methylaminomethyl)-phenylimino}-methyl]-4,6-di-tert-butylophenol (L2H) were prepared and after deprotonation they were reacted with VOCl3 or MCl4 (where M = Zr or Ti) to produce corresponding complexes (L1-V, L2-V, L1-Zr, L2-Ti) with good yields. All new compounds were characterized by the 1H and 13C NMR as well as FTIR spectroscopic methods. Upon activation with Et2AlCl or EtAlCl2, both the vanadium complexes exhibited exceptionally high catalytic activities in the ethylene polymerization (up to 69,000 kg/(molV?h) for L1-V and 101,500 kg/(molV?h) for L2-V) and remarkable thermal stability, and they produced UHMWPE. The complexes of group 4 metals were tested in the ethylene polymerization in conjunction with MMAO and Al(iBu)3/Ph3CB(C6F5)4, and L1-Zr was highly active (11,300 kg/(molZr?h)) and L2-Ti was moderately active (750 kg/(molTi?h)) when activated with MMAO. Furthermore, L1-2-V/EtAlCl2 systems were found to be very efficient in 1-octene incorporation and they produced copolymers with narrow chemical composition distributions and very narrow molecular weight distributions (Mw/Mn ≈ 2). In contrast to them, the catalysts based on titanium and zirconium complexes in conjunction with Al(iBu)3/Ph3CB(C6F5)4 gave copolymers with very broad comonomer and molecular weight distributions as well as with high molecular weights (Mw = 440,000–690,000 g/mol). It was also found that the chain transfer mechanism involved in the copolymerization process in the presence of vanadium and group 4 metal complexes was different.