6000-43-7Relevant articles and documents
High tenacity regenerated chitosan fibers prepared by using the binary ionic liquid solvent (Gly·HCl)-[Bmim]Cl
Ma, Bomou,Qin, Aiwen,Li, Xiang,He, Chunju
, p. 300 - 305 (2013)
A binary ionic liquid system was confirmed to be a promising solvent to dissolve chitosan, and the regenerated chitosan fibers were prepared by wet and dry-wet spinning technique respectively. The SEM results show that the chitosan fibers prepared by wet spinning technique present striated surface and round cross section, and the chitosan fibers prepared by dry-wet spinning technique present smooth surface and irregular cross section. The mechanical testing results show that the regenerated chitosan fibers present relatively high tenacity, especially, these prepared by dry-wet spinning process present excellent strength and initial modulus, i.e. 2.1 cN/dtex and 83.5 cN/dtex, which is stronger than that of most reported chitosan fibers. The FT-IR results show that the dissolution of chitosan in the binary ionic liquid system is due to the protonation of NH2 groups in the chitosan chains. Furthermore, a possible reaction during the dissolution and regeneration process is proposed.
Preparation of high strength chitosan fibers by using ionic liquid as spinning solution
Li, Lu,Yuan, Bing,Liu, Shiwei,Yu, Shitao,Xie, Congxia,Liu, Fusheng,Guo, Xianying,Pei, Lijun,Zhang, Baoquan
, p. 8585 - 8593 (2012)
The morphology and mechanical properties of chitosan fibers obtained by wet-spinning using chitosan-[Gly]Cl (glycine chloride) ionic liquid as spinning dope solution are reported for the first time. The objectives were to understand both how the microstructure of the fibers could be modified and how the mechanical properties were improved by means of using [Gly]Cl ionic liquid as the spinning solution. In the new system, the main component chitosan (the degree of deacetylation was 86%, the molecular weight was about 1.5 × 106) was dissolved in an aqueous [Gly]Cl ionic liquid solution; the fibers were then spun using a sodium sulfate (Na2SO 4)/ethanol (C2H5OH) aqueous solution as the coagulant, and then directly dried under freeze-drying. The fibers spun from the above mentioned system have the chitosan I crystal form, and the breaking tenacity (3.77 cN dtex-1) is 4 times more than that (0.86 cN dtex-1) from an acetic acid system. The orientation and crystallinity of fibers spun in [Gly]Cl solution was enhanced with an increase of spin stretch ratio, and thereby the mechanical properties of the fibers were improved. Moreover, the fibers had a smooth surface as well as a round and compact structure. More to the point, the used [Gly]Cl could be recovered by simple post processing and the chitosan fibers spun in the recycled [Gly]Cl solution also had a strong breaking tenacity. Therefore, this study verified that [Gly]Cl is a new spinning dope solution for preparing chitosan fibers with strong mechanical properties. The Royal Society of Chemistry 2012.
Efficient novel eutectic-mixture-mediated synthesis of benzoxazole-linked pyrrolidin-2-one heterocycles
Anouar, El Hassane,Geesi, Mohammed H.,Guionneau, Philippe,Kaiba, Abdellah,Ouerghi, Oussama,Riadi, Yassine
, (2020/12/29)
In this study, new benzoxazole-linked pyrrolidinone heterocyclic compounds were synthesized by an eco-efficient strategy using substituted benzylamines and 2-aminophenol under ultrasonic irradiation in the presence of a newly designed metal-free deep eutectic solvent (DES). This DES was prepared by using a eutectic mixture of urea and a synthesized glycine-derived ionic liquid. X-ray diffraction and infrared spectroscopy were employed to investigate the structure of the ionic liquid and characterize the DES, respectively. This method exhibited key advantages of high productivity, a short reaction time, and simple processing. Moreover, this DES was easily separated from reaction mixtures and can be recycled for multiple reactions.
LAT1 activity of carboxylic acid bioisosteres: Evaluation of hydroxamic acids as substrates
Zur, Arik A.,Chien, Huan-Chieh,Augustyn, Evan,Flint, Andrew,Heeren, Nathan,Finke, Karissa,Hernandez, Christopher,Hansen, Logan,Miller, Sydney,Lin, Lawrence,Giacomini, Kathleen M.,Colas, Claire,Schlessinger, Avner,Thomas, Allen A.
supporting information, p. 5000 - 5006 (2016/10/05)
Large neutral amino acid transporter 1 (LAT1) is a solute carrier protein located primarily in the blood–brain barrier (BBB) that offers the potential to deliver drugs to the brain. It is also up-regulated in cancer cells, as part of a tumor's increased metabolic demands. Previously, amino acid prodrugs have been shown to be transported by LAT1. Carboxylic acid bioisosteres may afford prodrugs with an altered physicochemical and pharmacokinetic profile than those derived from natural amino acids, allowing for higher brain or tumor levels of drug and/or lower toxicity. The effect of replacing phenylalanine's carboxylic acid with a tetrazole, acylsulfonamide and hydroxamic acid (HA) bioisostere was examined. Compounds were tested for their ability to be LAT1 substrates using both cis-inhibition and trans-stimulation cell assays. As HA-Phe demonstrated weak substrate activity, its structure–activity relationship (SAR) was further explored by synthesis and testing of HA derivatives of other LAT1 amino acid substrates (i.e., Tyr, Leu, Ile, and Met). The potential for a false positive in the trans-stimulation assay caused by parent amino acid was evaluated by conducting compound stability experiments for both HA-Leu and the corresponding methyl ester derivative. We concluded that HA's are transported by LAT1. In addition, our results lend support to a recent account that amino acid esters are LAT1 substrates, and that hydrogen bonding may be as important as charge for interaction with the transporter binding site.
