Cobalt‐based metal coordination polymers with 4,4′‐bipyridinyl groups: highly efficient catalysis for one‐pot synthesis of 3,4‐dihydropyrimidin‐2(1H)‐ones under solvent‐free conditions

Three new metal coordination complexes, namely [Co(BPY)₂(H₂O)₂](BPY)(BS)₂(H₂O)₄ ( 1 ), [Co(BPY)₂(H₂O)₄](ABS)₂(H₂O)₂ ( 2 ) and [Co(BPY)(H₂O)₄](MBS)₂ ( 3 ) (BPY = 4,4′‐bipyridine, BS = phenylsulfonic acid, ABS = p‐aminobenzenesulfonic acid, MBS = p‐methylbenzenesulfonic acid), were obtained under hydrothermal conditions. Complexes 1 , 2 , 3 were structurally characterized using single‐crystal X‐ray diffraction and infrared spectroscopy. All of them display low‐dimensional motifs: complex 1 displays a two‐dimensional structure; and complexes 2 and 3 exhibit a one‐dimensional tape structure. Through strong intermolecular hydrogen bonding interactions and weak packing interactions, all of them further stack to generate a three‐dimensional supramolecular architecture. Catalysts 1 , 2 , 3 were involved in the green synthesis of a variety of 3,4‐dihydropyrimidin‐2(1H)‐ones under solvent‐free conditions through Biginelli reactions. The corresponding catalytic product was obtained in quantitative yields (99%) under eco‐friendly synthesis conditions for the variety of reactions. Catalysts 1 , 2 , 3 exhibit excellent efficiency for the desired product, and their catalytic performance shows the following order: 2  >  1  ≈  3 , which can be ascribed to the hydrophobic interactions of different phenylsulfonate groups. The catalytic performance for the Biginelli reaction is not only dependent on the selected solvents, but also inversely proportional to the polarities of the solvents. Copyright © 2016 John Wiley & Sons, Ltd.     

Metabolism studies on prim‐O‐glucosylcimifugin and cimifugin in human liver microsomes by ultra‐performance liquid chromatography quadrupole time‐of‐flight mass spectrometry

Prim‐O‐glucosylcimifugin (PGCN) and cimifugin (CN) are major constituents of Radix Saposhnikoviae that have antipyretic, analgesic and anti‐inflammatory pharmacological activities. However, there were few reports with respect to the metabolism of PGCN and CN in vitro. In this paper, we describe a strategy using ultra‐performance liquid chromatography quadrupole time‐of‐flight mass spectrometry (UPLC‐Q‐TOF‐MS) for fast analysis of the metabolic profile of PGCN and CN in human liver microsomes. In total, five phase I metabolites of PGCN, seven phase I metabolites and two phase II metabolites of CN were identified in the incubation of human liver microsomes. The results revealed that the main phase I metabolic pathways of PGCN were hydroxylation and hydrolysis reactions. The phase I metabolic pathways of CN were found to be hydroxylation, demethylation and dehydrogenation. Meanwhile, the results indicated that O‐glucuronidation was the major metabolic pathway of CN in phase II metabolism. The specific UDP‐glucuronosyltransferase (UGT) enzymes responsible for CN glucuronidation metabolites were identified using recombinant UGT enzymes. The results indicated that UGT1A1, UGT1A9, UGT2B4 and UGT2B7 might play major roles in the glucuronidation of CN. Overall, this study may be useful for the investigation of metabolic mechanism of PGCN and CN, and it can provide reference and evidence for further pharmacodynamic experiments. Copyright © 2016 John Wiley & Sons, Ltd.     

Acetate anion-selective encapsulation in the ellipsoidal cavity of symmetrical α,α′,δ,δ′-tetramethyl-cucurbit[6]uril

Four symmetrical α,α′,δ,δ′-tetramethyl-cucurbit[6]uril-based compounds have been prepared and characterised by X-ray crystallography. Their crystal structures displayed the acetate anion-selective encapsulating capability of symmetrical α,α′,δ,δ′-tetramethyl-cucurbit[6]uril. The host–guest interaction between the symmetrical α,α′,δ,δ′-tetramethyl-cucurbit[6]uril and the acetate anion in aqueous solution has also been observed by variable temperature ¹H NMR spectroscopy.     

Synthesis and Characterization of Novel Liquid Crystalline Epoxides with Lateral Substituent Showing Imposing Shape Memory Properties

In this work, a series of novel shape memory liquid crystalline (LC) epoxides with lateral substituent were prepared and characterized. Dynamic mechanical analysis (DMA) and shape memory testing were used to investigate on the thermo-mechanical properties and shape memory effects of prepared samples. The results showed that the modulus in the rubbery region (E_R ) decreased as the length of lateral alkyl group increases. And more than 95% of the deformation can be fixed as the sample was cooled down below the glass transition temperature (T_g), which was determined by differential scanning calorimetry (DSC) measurement, and can be recovered completely as heating. Effects of the curing agent and substituent on the shape memory behavior were also studied. We found that LC epoxides cured by aromatic diamine have a higher recovery speed. The recovering speeds of the shape memory decreased as the length of lateral alkyl group inscreased. The local ordered structures and the lateral substituent played an important role in shape memory effects.