21685-51-8Relevant articles and documents
Diastereoselective protonation of enolates of chiral Schiff bases
Tabcheh, Mohamed,Guibourdenche, Christel,Pappalardo, Louis,Roumestant, Marie-Louise,Viallefont, Philippe
, p. 1493 - 1495 (1998)
Diastereoselective protonation of potassium enolates of chiral Schiff bases prepared from racemic α-amino esters and 2-hydroxypinan-3-one afforded, after mild cleavage of the imine function, optically active α- amino esters.
Homochiral Dodecanuclear Lanthanide "cage in Cage" for Enantioselective Separation
Zhu, Chengfeng,Tang, Haitong,Yang, Keke,Fang, Yu,Wang, Kun-Yu,Xiao, Zhifeng,Wu, Xiang,Li, Yougui,Powell, Joshua A.,Zhou, Hong-Cai
supporting information, p. 12560 - 12566 (2021/08/23)
It is extremely difficult to anticipate the structure and the stereochemistry of a complex, particularly when the ligand is flexible and the metal node adopts diverse coordination numbers. When trivalent lanthanides (LnIII) and enantiopure amino acid ligands are utilized as building blocks, self-assembly sometimes yields rare chiral polynuclear structures. In this study, an enantiopure carboxyl-functionalized amino acid-based ligand with C3 symmetry reacts with lanthanum cations to give a homochiral porous coordination cage, (Δ/λ)12-PCC-57. The dodecanuclear lanthanide cage has an unprecedented octahedral "cage-in-cage"framework. During the self-assembly, the chirality is transferred from the enantiopure ligand and fixed by the binuclear lanthanide cluster to give 12 metal centers that have either Δor λ homochiral stereochemistry. The cage exhibits excellent enantioselective separation of racemic alcohols, 2,3-dihydroquinazolinones, and multiple commercially available drugs. This finding exhibits a rare example of a multinuclear lanthanide complex with a dual-walled topology and homochirality. The highly ordered self-assembly and self-sorting of flexible amino acids and lanthanides shed light on the chiral transformation between different complicated artificial systems that mimic natural enzymes.
Mechanoresponsive, proteolytically stable and biocompatible supergelators from ultra short enantiomeric peptides with sustained drug release propensity
Basu, Anindya,Christman, Ryann M.,Duttkonar, Anita,Harjit, Jeena,Mehra, Radha Rani,Mishra, Anil K.,Tiwari, Amit K.
, p. 6346 - 6354 (2020/05/13)
Stimuli-responsive low molecular weight hydrogelators attract immense interest from diverse segments of biomedicine and biotechnology. Distinctly, herein we report newly synthesized enantiomeric ultrashort peptides of general formula Me-(CH2)8-CO-NH-CH(X)-COOH, where X = CH2Ph in hydrogelators I (l-Phe) and II (d-Phe) respectively, which display excellent self-assembling propensity in physiological buffer at room temperature. Interestingly these biomolecules were endowed with mechanoresponsiveness, injectability and high mechanical integrity as confirmed by rheological measurements. Importantly they revealed resistance towards proteolytic degradation. Indeed dose dependent cell viability studies using MTT assay in four different cell lines, namely PANC-1, S1, HCT-116 and MDAMB-231, further confirmed the biocompatibility of the hydrogelators in vitro. The structural aspect of β-sheets of the hydrogelators was concluded on the basis of temperature dependent NMR, IR, PXRD and computational studies. We developed a user friendly delivery system, hydrogel nanoparticles (HNPs), with our mechanoresponsive and biocompatible hydrogelators, as these particles exhibited promising influence due to their enhanced surface area. Also the HNPs revealed excellent drug release kinetics for the model drugs 5FU/doxorubicin under physiological conditions in a sustained manner depending on the physicochemical parameters of the drugs. Taking these results together we envision that our designed hydrogelators and the delivery vehicle generated therefrom might represent a promising tool for administration of significant drug concentrations at lesion sites for a prolonged period, thus providing a better strategy for quick pain relief, rapid recovery and reduced systemic side effects.