1.Tuning the adsorption behaviors of water, methanol, and ethanol in a porous material by varying the flexibility of substituted groups.
Sha Y1, Bai S2, Lou J1, Wu D1, Liu B1, Ling Y2. Dalton Trans. 2016 Apr 14. [Epub ahead of print]
Exploring the adsorption and separation of water, methanol, and ethanol is important concerning the use of a sustainable energy source from biofuel. In this paper, the effects of the flexibility of substituted groups have been studied based on three iso-reticular metal-organic frameworks (MOFs), in which the pore surface is decorated with propargyl (-CH2-C[triple bond, length as m-dash]CH), allyl (-CH2-CH[double bond, length as m-dash]CH2), and propyl (-CH2-CH2-CH3) groups respectively. These substituted groups stretch into the channel, acting as gates, and the gate-opening for guests is controlled by the flexibility as well as host-guest interactions. Our study results indicate that (i) the adsorption capacity of water, methanol and ethanol enhances accordingly with the increase of the flexibility of substituted groups; (ii) the adsorptive discrimination of water, methanol, and ethanol on this porous sorbent could be tuned by varying the substituted groups.
2.Glycomimetics Targeting Glycosyltransferases: Synthetic, Computational and Structural Studies of Less-Polar Conjugates.
Ghirardello M1, de Las Rivas M2, Lacetera A3, Delso I1,4, Lira-Navarrete E1, Tejero T1, Martín-Santamaría S5, Hurtado-Guerrero R6,7,8, Merino P9. Chemistry. 2016 Apr 13. doi: 10.1002/chem.201600467. [Epub ahead of print]
The Leloir donors are nucleotide sugars essential for a variety of glycosyltransferases (GTs) involved in the transfer of a carbohydrate to an acceptor substrate, typically a protein or an oligosaccharide. A series of less-polar nucleotide sugar analogues derived from uridine have been prepared by replacing one phosphate unit with an alkyl chain. The methodology is based on the radical hydrophosphonylation of alkenes, which allows coupling of allyl glycosyl compounds with a phosphate unit suitable for conjugation to uridine. Two of these compounds, the GalNAc and galactose derivatives, were further tested on a model GT, such as GalNAc-T2 (an important GT widely distributed in human tissues), to probe that both compounds bound in the medium-high micromolar range. The crystal structure of GalNAc-T2 with the galactose derivative traps the enzyme in an inactive form; this suggests that compounds only containing the β-phosphate could be efficient ligands for the enzyme.
3.Novel N-allyl/propargyl tetrahydroquinolines: Synthesis via three-component cationic imino Diels-Alder reaction, binding prediction and evaluation as cholinesterase inhibitors.
Rodríguez YA1, Gutiérrez M1, Ramírez D2, Alzate-Morales J2, Bernal CC3, Güiza FM3, Romero Bohórquez AR3. Chem Biol Drug Des. 2016 Apr 17. doi: 10.1111/cbdd.12773. [Epub ahead of print]
New N-allyl/propargyl 4-substituted 1,2,3,4-tetrahydroquinolines derivatives were efficiently synthesized using acid-catalyzed three components cationic imino Diels-Alder reaction (70-95%). All compounds were tested in vitro as dual acetylcholinesterase (AChE) and butyryl-cholinesterase (BChE) inhibitors and their potential binding modes, and affinity, were predicted by molecular docking and binding free energy calculations (∆G), respectively. The compound 4af (IC50 = 72 μM) presented the most effective inhibition against AChE despite its poor selectivity (SI= 2), while the best inhibitory activity on BChE was exhibited by compound 4ae (IC50 = 25.58 μM) with considerable selectivity (SI=0.15). Molecular docking studies indicated that the most active compounds fit in the reported AChE and BChE active sites. Moreover, our computational data indicated a high correlation between the calculated ∆G and the experimental activity values in both targets.
4.Different antibacterial activity of novel theophylline-based ionic liquids - Growth kinetic and cytotoxicity studies.
Borkowski A1, Ławniczak Ł2, Cłapa T3, Narożna D4, Selwet M3, Pęziak D2, Markiewicz B2, Chrzanowski Ł2. Ecotoxicol Environ Saf. 2016 Apr 12;130:54-64. doi: 10.1016/j.ecoenv.2016.04.004. [Epub ahead of print]
The aim of this study was to investigate novel theophylline-based ionic liquids and their cytotoxic effects towards model Gram-positive and Gram-negative bacteria (Bacillus cereus and Escherichia coli, respectively). Growth kinetics, respiratory rates and dehydrogenase activities were studied in the presence of ionic liquids at concentrations ranging from 10 to 1000mg/L. Additionally, the influence of ionic liquids on bacterial cells associated with specific interactions based on the structure of cell wall was evaluated. This effect was assessed by viability tests and scanning electron microscope observations. The obtained results confirmed that ionic liquids exhibit different levels of toxicity in relation to Gram-positive and Gram-negative bacteria. Those effects are associated with the chemical structure of the cationic species of the ionic liquids and their critical micelle concentration value. It was established that the presence of an alkyl or allyl group increased the toxicity, whereas the presence of an aryl group in the cation decreased the toxic effect of ILs.