查找使用阿拉丁产品的科研文献

Synthesis of 2,3-dihydroquinazolin-4(1H)-ones catalyzed by α-chymotrypsin

Shi-Guo Zhang,Zong-Bo Xie,Lian-Sheng Liu,Meng Liang,Zhang-Gao Le

We discovered that α -chymotrypsin has a promiscuous ability to catalyze the cyclocondensation of aromatic and aliphatic aldehydes with 2-aminobenzamides to afford the corresponding 2,3-dihydroquinazolin-4(1 H )-ones successfully in high yields (90%–98%) under alcohol solvent. The catalytic activity of α -chymotrypsin was evaluated through investigating the temperature, the enzyme loading and the ratio of substrates in the enzyme-catalyzed reactions. The present method proves to be efficient and environmentally friendly in terms of short reaction time, high yield, green catalyst and the clean products obtained without further purification processes.

Self-healing polyurethane elastomer based on 2-ureido-4[1H]-pyrimidinone

Zhijia Zhang,Huifeng Mei,Qiang Wang,Rui Li,Guojun Wang,Hao Wei,Xiao Ouyang

Unlike the organisms in nature, the synthetic materials are difficult to repair the damage via self-regulation. Even the self-healing materials generally require the external stimuli (e.g., temperature, pressure, light, etc ) to repair themselves. In this paper, self-healing polyurethane elastomer was designed and prepared based on 2-ureido-4[1 H ]-pyrimidinone compound by the simple physical blending method. The tensile strength and the elongation at break of the self-healing polyurethane elastomer were 0.65 MPa and 623.1%, respectively. The healing performance was measured by cut-off experiment, showing that the fracture of the self-healing polyurethane elastomer was healed at room temperature without external stimuli and kept excellent mechanic properties. The healing efficiencies of the tensile strength and the elongation at break were achieved to 87.7% (0.57 MPa) and 71.7% (446.7%) after healing at room temperature with 30 h, respectively. When the temperature was up to 80 °C, the healing time curtailed at 1 h. And the tensile strength and the elongation at break were recovered to 0.59 MPa and 532.1%, respectively. These promising results provide a strategy that allows increasing the life cycle of materials, adapting them to a circular economy model, thus reducing the generation of waste.

The characteristics and mechanism of hydrogen bonding assembly in linear polyurethane with multiple pendant 2-ureido-4[1H]-pyrimidone units

Yimei Chen,Wei Yang,Juan Liu,Yuanliang Wang,Yanfeng Luo

2-Ureido-4[1 H ]-pyrimidone (UPy) can form strong quadruple hydrogen bonding (H-bonding) and is widely used to construct supramolecules. Though the H-bonding assembly of UPy-containing polymers has been widely reported, little attention is paid to the H-bonding characteristics and mechanism of UPy-containing polyurethanes. Here, by using UPy- p -PDLLA-SMPU, a linear polyurethane with multiple pendant UPy units as the model polymer, the H-bonding assembly characteristics in solution, solid film and melt are systematically investigated. It is found that the UPy units mainly exist as free monomers in DMSO, UPy dimers in CHCl 3 , and both free monomers and dimers in DMF. The dimerization of UPy can promote the H-bonding of urea and urethane groups and thus the formation of hard segment aggregates. Thereby, the thermal resistance and reversibility of the H-bonds are significantly enhanced in both UPy- p -PDLLA-SMPU film and melt. UPy- p -PDLLA-SMPU can transition from a rubber state (70°C–85°C) to a viscous flow state (≥120°C), presenting the characteristics of both chemically crosslinked and linear polyurethanes. This work provides a clear picture on the H-bonding assembly of UPy units together with urea and urethane groups in UPy- p -PDLLA-SMPU. The obtained assembly characteristics and mechanism are beneficial for the design and processing of UPy-based physically crosslinked polyurethanes.

3-Hydroxy-pyridin-4(1H)-ones as siderophores mediated delivery of isobavachalcone enhances antibacterial activity against pathogenic Pseudomonas aeruginosa

Yong-Jun Huang,Xiao-Lin Zhong,Yi-Peng Zang,Ming-Han Yang,Jing Lin,Wei-Min Chen

The natural prenylated chalcone isobavachalcone ( IBC ) shows good antibacterial activity against Gram-positive bacteria but is ineffective against Gram-negative bacteria, most likely due to the outer membrane barrier of Gram-negative bacteria. The Trojan horse strategy has been shown to be an effective strategy to overcome the reduction in the permeability of the outer membrane of Gram-negative bacteria. In this study, eight different 3-hydroxy-pyridin-4(1 H )-one-isobavachalcone conjugates were designed and synthesized based on the siderophore Trojan horse strategy. The conjugates exhibited 8- to 32-fold lower minimum inhibitory concentrations (MICs) and 32- to 177-fold lower half-inhibitory concentrations (IC 50 s) against Pseudomonas aeruginosa PAO1 as well as clinical multidrug-resistant (MDR) strains compared to the parent IBC under iron limitation. Further studies showed that the antibacterial activity of the conjugates was regulated by the bacterial iron uptake pathway under different iron concentration conditions . Studies on the antibacterial mechanism of conjugate 1b showed that it exerts antibacterial activity by disrupting cytoplasmic membrane integrity and inhibiting cell metabolism. Finally, conjugate 1b showed a lower cytotoxic effects on Vero cells than IBC and a positive therapeutic effect in the treatment of bacterial infections caused by Gram-negative bacteria PAO1. Overall, this work demonstrates that IBC can be delivered to Gram-negative bacteria when combined with 3-hydroxy-pyridin-4(1H)-ones as siderophores and provides a scientific basis for the development of effective antibacterial agents against Gram-negative bacteria.

SYNTHESES OF COBALT AND NICKEL COORDINATION POLYMERS COMPOSED OF 1,3-ADAMANTANEDICARBOXYLATE AND BIS(4-(1H-IMIDAZOL-1-YL)PHENYL) METHANONE LIGANDS

Wang G. -F.,Sun S. -W.

Abstract Two coordination polymers, {[Co 2 (L 1 ) 2 (adc) 2 ]·5H 2 O} n ( 1 ) and {[Ni(L 1 ) 2 (Hadc) 2 ]} n ( 2 ) (L 1  = bis(4-(1 H -imidazol-1-yl)phenyl)methanone, H 2 adc = adamantane-1,3-dicarboxylic acid), have been synthesized and structurally characterized. In 1 , Co1 is five-coordinated by three oxygen atoms of two adc 2– and two nitrogen atoms from two L 1 ligands. The neighboring [Co(adc)] 2 dimers are linked through four L 1 ligands to form a 1D ladder structure. In 2 , Ni1 is six-coordinated by two oxygen atoms from two Hadc – ligands, four nitrogen atoms from four distinct L 1 ligands to give a slight distorted octahedral geometry. The [Ni(Hadc) 2 ] units are bridged by L 1 ligands to form 1D looped chains.

Two zinc and cadmium coordination polymers constructed with bis(4-(1H-imidazol-1-yl)phenyl)methanone and naphthalene-1,4-dicarboxylate ligands: synthesis and structural characterization

Gao-Feng Wang,Hai-Ying Yang,De-Qun Peng,Shu-Wen Sun

Two coordination polymers, [Zn 2 (bipmo) 2 (1,4-nda) 2 ] n ( 1 ), {[Cd(bipmo)(1,4-nda)]·(H 2 O)} n ( 2 ), (bipmo = bis(4-(1 H -imidazol-1-yl)phenyl)methanone, H 2 (1,4-nda) = naphthalene-1,4-dicarboxylic acid), were synthesized under solvothermal conditions. The complexes have been characterized by elemental analyses, IR spectroscopy and single-crystal X-ray diffraction. Complex 1 possesses 3D 2-fold interpenetrating nets with the Schläfli symbol {6 5 ·8}. Complex 2 consists a 3D net with the Schläfli symbol {4 4 ·6 10 ·8}. The luminescent properties of complexes 1 and 2 have been investigated.

Synthesis and antitumor activities of 4-(1H-indol-1-yl)-4-oxobutanoic acid spliced podophyllotoxin derivatives

Jun Yang,Guang-Ping Liang,Xiong-Li Liu

To investigate the effects and mechanisms of 4-(1H-indol-1-yl)-4-oxobutanoic acid spliced podophyllotoxin derivatives (3a–3l) on tumor cells. The MTT method was adopted to evaluate (3a–3l) antitumor activity in vitro against A549 cells, A549/DDP cells, MCF-7 cells. The results showed that compound 3l had the most prominent inhibitory effect and high selectivity with IC50 18.53 ± 1.51 µM against A549/DDP cells. Meanwhile, the effects of compound 3l on the nuclear state, cell cycle and apoptosis of A549/DDP cells showed that compound 3l induced apoptosis by delaying the G2/M phase of A549/DDP cell cycle. In addition, molecular docking of compound 3l also showed that it could form a good hydrogen bond with ARG-158 (d = 2.6, 2.7 Å) and HIS-406 (d = 2.5 Å) at the colchicine site of tubulin. Compound 3l could provide lead compound for the development of new multi-drug resistant anti-tumor drugs.

Novel 3-hydroxypyridin-4(1H)-One derivatives as ferroptosis inhibitors with iron-chelating and reactive oxygen species scavenging activities and therapeutic effect in cisplatin-induced cytotoxicity

Changjun Zhang,Yi Lu,Jingqi Zhang,Anjie Zang,Jinhui Ren,Zhiyuan Zheng,Miaoliang Fan,Yuanyuan Xie

Recent advances in understanding the role of iron and ROS in cell death suggest new therapeutic avenues to treat organ damage including acute kidney injury (AKI). Inhibiting ferroptosis was expected to have great potential for the treatment of this disease. Ferroptosis is characterized by iron-dependent lipid peroxidation and currently, a majority of reported ferroptosis inhibitors belong to either radical-trapping antioxidants or iron chelators . However, clinically used iron chelators such as deferoxamine and deferiprone have limited efficacy against ferroptosis (generally with EC 50  > 100 μM), despite their proven safety. Herein, we present the rational design of novel ferroptosis inhibitors by incorporating the naturally occurring cinnamic acid scaffold and the 3-hydroxypyridin-4(1 H )-one iron-chelating pharmacophore . Through ABTS ˙ + radical-scavenging assay, oxygen radical absorbance capacity (ORAC) measurement, Fe 3+ affinity evaluation, and anti-erastin-induced HT22 cell ferroptosis assays, we identified compound 9c as the most prospective ferroptosis inhibitor (ABTS ˙ + , IC 50  = 4.35 ± 0.05 μM; ORCA = 23.79 ± 0.56 TE; pFe 3+  = 18.59; EC 50  = 14.89 ± 0.08 μM, respectively). Notably, 9c dose-dependently alleviated cell death in cisplatin-induced AKI model. Our results provide insight into the development of new ferroptosis inhibitors through rational incorporation of pharmacophores from existing ferroptosis inhibitors, and compound 9c could be a promising lead compound worth further investigation.

Crystal structure of catena-poly[triaqua-[bis(m2-4-(1H-1,2,4-triazol-1-yl)benzoato-k2O:O')-(4-(1H-1,2,4-triazol-1-yl)benzoato-k1O)-praseodymium (III) monohydrate], C27H26N9O10Pr

Li Liu,Huan-Mei Guo,Li-Li Liu,Xin-Ru Qian

C 27 H 26 N 9 O 10 Pr, monoclinic, P 2 1 / c , a  = 13.2280(12) Å, b  = 5.5628(5) Å, c  = 41.140(3) Å, β  = 105.109(2)°, V  = 2922.6(4) Å 3 , Z  = 4, R gt ( F ) = 0.0426, w R ref ( F 2 ) = 0.0803, T  = 298.15 K.

l-Proline-catalyzed synthesis of 2-aryl-2,3-dihydroquinolin-4(1H)-ones in ionic liquids

Wang Yun,Zhang Qiang-qiang,Liu Zi-yin,Xie Zhuang-dong

The synthesis of 2-aryl-2,3-dihydroquinolin-4(1 H )-ones from aromatic aldehydes and and 1-(2-aminophenyl)ethanone catalyzed by l -proline in ionic liquids was achieved for the first time. High yields up to 88.7% were achieved. Mild reaction conditions, enhanced rates, improved yields, and reagents’ reactivity, which is different from that in standard organic solvents, are the remarkable features observed in ionic liquids. In addition, the reaction mechanism was studied using computational methods, and the results were consistent with experimental findings. Graphical abstract

Discovery of N-hydroxy-4-(1H-indol-3-yl)butanamide as a histone deacetylase inhibitor

Jiang Bian,Yepeng luan,Chunbo Wang,Lei Zhang

Preparation and Characterization of Attractive Poly(amino acid) Hydrogels Based on 2-Ureido-4[1H]-pyrimidinone

Shi Zhen,Wang Qi,Li Gui-Fei,Shou Yu-Feng,Zong Hong-Jie,Yan Shi-Feng,Zhang Kun-Xi,Yin Jing-Bo

Self-healing hydrogels with the shear-thinning property are novel injectable materials and are superior to traditional injectable hydrogels. The self-healing hydrogels based on 2-ureido-4[1 H ]-pyrimidinone (UPy) have recently received extensive attention due to their dynamic reversibility of UPy dimerization. However, generally, UPy-based self-healing hydrogels exhibit poor stability, cannot degrade in vivo and can hardly be excreted from the body, which considerably limit their bio-application. Here, using poly (l -glutamic acid) (PLGA) as biodegradable matrix, branching α-hydroxy- ω -amino poly(ethylene oxide) (HAPEO) as bridging molecule to introduce UPy, and ethyl acrylate polyethylene glycol (MAPEG) to introduce double bond, the hydrogel precursors (PMHU) are prepared. A library of the self-healing hydrogels has been achieved with well self-healable and shear-thinning properties. With the increase of MAPEG grafting ratio, the storage modulus of the self-healing hydrogels decreases. The self-healing hydrogels are stable in solution only for 6 h, hard to meet the requirements of tissue regeneration. Consequently, ultraviolet (UV) photo-crosslinking is involved to obtain the dual crosslinking hydrogels with enhanced mechanical properties and stability. When MAPEG grafting ratio is 35.5%, the dual crosslinking hydrogels can maintain the shape in phosphate-buffered saline solution (PBS) for at least 8 days. Loading with adipose-derived stem cell spheroids, the self-healing hydrogels are injected and self-heal to a whole, and then they are crosslinked in situ via UV-irradiation, obtaining the dual crosslinking hydrogels/cell spheroids complex with cell viability of 86.7%±6.0%, which demonstrates excellent injectability, subcutaneous gelatinization, and biocompatibility of hydrogels as cell carriers. The novel PMHU hydrogels crosslinked by quadruple hydrogen bonding and then dual photo-crosslinking of double bond are expected to be applied for minimal invasive surgery or therapies in tissue engineering.