Enhanced antifungal activities of four Zn(II) complexes based on uniconazole

Four Zn(II) complexes, [Zn L ₂(SO₄)]_n ( 1 ), [Zn L ₄(H₂O)₂]?2(NO₃)?4EtOH ( 2 ), [Zn L ₂Cl₂]? L ( 3 ), and [Zn L ₂Br₂]? L ( 4 ) ( L  = uniconazole), were synthesized using a hydrothermal method and characterized by elemental analysis, FT‐IR spectroscopy, and single‐crystal XRD. Complex 1 formed a one‐dimensional polymer chain. However, complexes 2 ‐ 4 were obtained as zero‐dimensional mononuclear coordination compounds. The antifungal activities of these complexes were then evaluated against four selected fungi using the mycelial growth rate method. The resulting data indicate that all complexes show better antifungal activities than their ligands and mixtures. In addition, the interactions between the metal salts of complexes 1 ‐ 4 and uniconazole seem to be synergistic. Furthermore, the polymer chain structure of complex 1 significantly enhanced the bioactivity, especially against Botryosphaeria ribis ( I ). Density functional theory (DFT) calculations were carried out to help explain the enhanced bioactivity after the formation of Zn(II) complexes. The resulting data show that the HOMO–LUMO energy gaps of complexes 1 ‐ 4 (0.0578, 0.0946, 0.1053, and 0.1245 eV) are smaller than that of the free ligand (0.1247 eV) and correlate with the antifungal activity of the zinc complexes.     

Synthesis and antitumor and antibacterial evaluation of fluoroquinolone derivatives(Ⅲ):Mono- and bis-Schiff-bases

To further explore an efficient modified route for the shift from an antibacterial fluoroquinolone to an antitumor one,mono-Schiff bases 6a-6h related to ciprofloxacin C3 carbonylhydrazone and bis-Schiff bases 4a-4h corresponding to C3/C7 carbonylhydrazone/hydrazone attached on a skeleton of ciprofloquinolone were designed and synthesized,and their in vitro antitumor activity against CHO,HL60,L1210 cells and antibacterial activity against Staphylococcus aureus and Escherichia coli were also reported.     

Sortase-Mediated Transpeptidation for Site-Specific Modification of Peptides, Glycopeptides, and Proteins

Sortases are a family of transpeptidases found in Gram-positive bacteria responsible for covalent anchoring of cell surface proteins to bacterial cell walls. It has been discovered that sortase A (SrtA) of Staphylococcus aureus origin is rather promiscuous and can accept various molecules as substrates. As a result, SrtA has been widely used to ligate peptides and proteins with a variety of nucleophiles, and the ligation products are useful for research in chemical biology, proteomics, biomedicine, etc. This review summarizes the recent applications of SrtA with special emphasis on SrtA-catalyzed ligation of carbohydrates with peptides and proteins.     

The Novel Preparation of Hydrocinnamonitriles via the Reduction of α-Phenylsulfonyl Cinnamonitriles with SmI2/CH2OH/THF System

Hydrocinnamonitriles were readily obtained via the reduction of α-phenylsulfonyl cinnamonitriles by SmI₂/CH₃OH/THF system.     

Matched/Mismatched Interactions in Chiral Brønsted Acid-Catalyzed Glycosylation Reactions with 2-Deoxy-Sugar Trichloroacetimidate Donors

The stereochemical outcome of glycosylation reactions of 2-deoxy-sugar trichloroacetimidates promoted by chiral Brønsted acids is shown to be dependent on both the chirality of the catalyst and the configuration of the leaving group. High levels of selectivity (1:16 α:β) can be obtained with (S)-catalysts and an α-trichloroacetimidate donor. Conversely, (R)-catalysts require longer reaction times and provide the product in much lower selectivity (6.6:1 α:β). These observations demonstrate that stereochemical “match” and “mismatch” between donor and acceptor are important factors in chiral Brønsted acid-promoted glycosylations.     

Modeling and calculation of thermal explosion time to ignition of cylindrical fireworks and crackers

To analyze the thermal safety of cylindrical fireworks and crackers in storage and transportation, this article establishes a physical model and a mathematical model of thermal explosion time to ignition of finite cylindrical fireworks and crackers. And in order to simplify the thermal explosion model, effective Biot number about boundary condition is deduced according to the theory of heat transfer. The partial differential equation of thermal explosion model are calculated with difference method in Matlab program, to obtain the time to ignition as well as the temperature–time history before explosion system explodes. The rationality of effective Biot number and calculation method is proved through comparison of calculation solution and literature solution. Being the first to solve the problem of two-dimensional thermal explosion unsteady-state model of fireworks and crackers, where the upper surface, lower surface, and side surface have different heat dissipation conditions. Meanwhile, calculation steps were shown about a type of fireworks.