Polyhydroxylated homoazepanes and 1-deoxy-homonojirimycin analogues: Synthesis and glycosidase inhibition study

The Johnson-Claisen rearrangement of D-gluco and L-ido-derived allylic orthoesters afforded gamma,delta-unsaturated ester that on ester reduction, epoxidation, regioselective oxirane opening by sodium azide and hydrogenation led to sugar amino alcohols--immediate precursors for 1-deoxy-homonojirimycin 3a,b, and polyhydroxylated homoazepanes 4a,b. Our synthetic approach and glycosidase inhibitory activity is reported.     

Synthesis and structural details of MSr2RECu2O7+δ(M-1212;0⩽δ<1) compounds with M = Al,Nb, Fe,Ru, Ga & Co and RE = Eu,Y

Synthesis and structural details of MSr₂RECu₂O_z (M-1212) compounds with M = Ga, Nb, Fe, Al and Co) and RE = Eu, Y are reported. Reitveld refinement of X-ray diffraction (XRD) patterns shows that all compounds are crystallized in single phase. Nb-, Fe- and Al-1212 possess tetragonal P4/mmm space group structure while the Ga-1212 and Co-1212 are crystallized in orthorhombic Ima2 space group. The change of space group from P4/mmm to Ima2 indicating towards the doubling of unit cell. The buckling angle [Cu(2)–O(2)–Cu(2) angle] shows that most of the studied samples are heavily under doped and hence they could not exhibit superconductivity. Thermogravimetric (TGA) analysis shows the M-1212 compounds to be more stable than widely studied 90 K superconductor Cu-1212 (RE-123).     

Preparation and characterization of polyindole–ZnO composite polymer electrolyte with LiClO<Subscript>4</Subscript>

This paper describes the preparation and conductivity studies of polyindole–ZnO composite polymer electrolyte (CPE) with LiClO₄. Polyindole–ZnO-based polymer nanocomposites were prepared by chemical method and characterized by XRD, infrared (IR), scanning electron microscope (SEM), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). The IR spectrum confirms the intermolecular interaction between polyindole and ZnO. The significant spectral changes of polyindole and ZnO nancomposites reveal the strong interaction between polyindole and ZnO nanoparticles. The structural morphologies of the ZnO, polyindole, and polyindole–ZnO are obtained from SEM. The TEM image of polyindole nanocomposite shows that ZnO is embedded in polyindole matrix. An enhanced conductivity of 4.405 × 10⁻⁷ S cm⁻¹ at 50 °C for the CPE was determined from impedance studies.     

超燃冲压发动机性能的准二维计算方法

为了能在双模态超燃冲压发动机流道方案初步论证中提供一种较快速的发动机性能计算方法,在二维N-S方程基础上,引入一维完全燃烧计算方法,提出了预估超燃冲压发动机性能的准二维计算方法。该方法能够计入激波、边界层分离等对发动机性能的影响,可在较短时间计算出整机推力、比冲性能和沿程热力学参数。通过对自由射流发动机计算,验证了此方法。并在此基础上,初步分析了燃料喷注位置和流道构型对发动机性能的影响。      

Pseudo-differential operators involving Watson transform

A class of pseudo-differential operators (p.d.o.'s) associated with the general Fourier kernel studied by Hardy and Titchmarsh is defined. A symbol class T ^m is introduced. It is shown that the p.d.o.'s associated with the symbol are continuous linear mappings of the Braaksma and Schuitman space T(λ,μ) into itself. An integral representation of p.d.o. is obtained. Some special forms of the symbol are considered. It is shown that these p.d.o.'s and their products are bounded in certain Sobolev type space.     

Dynamics of supercooled liquids and understanding the glass transition

The self-consistent mode coupling theory of glass transition is briefly reviewed. The existance of a temperature T_c, higher than the usual calorimetric glass transition temperature, across which the dynamics of the fluid becomes quite different are indicated through different experimental results. Above T_c the viscosity tends to diverge with a power law while for lower temperature this sharp transition is cutoff. Such changes in the transport properties can be understood from the self-consistent mode coupling theory. The relaxation functions predicted by the mode-coupling theory over different time scales are indicated. The models with proper wave-vector dependence are also discussed.     

Synthesis of Hexahydrospiro[pyrazolo[3,4‐b]quinoline‐4,1′‐pyrrolo[3,2,1‐ij]quinoline‐2′,5(1H,4′H)‐diones] from 5,6‐dihydro‐4H‐pyrrolo[3,2,1‐ij]quinoline‐1,2‐dione Using Fe3O4@Cu(OH)x as a Nanocatalyst

The tricyclic isatin, 5,6‐dihydro‐4H‐pyrrolo[3,2,1‐ij]quinoline‐1,2‐dione, undergoes three‐component, one‐pot reactions with 1‐aryl‐3‐methylpyrazole‐5‐amines and cyclohexane‐1,3‐diones producing hexacyclic spiro products, hexahydrospiro[pyrazolo[3,4‐b]quinoline‐4,1‐pyrrolo[3,2,1‐ij]quinoline‐2′,5(1H,4′H)‐diones]. Comparable spiro condensation products are also obtained using 4‐hydroxy‐2H‐1‐benzopyran‐2‐one in place of cyclohexane‐1,3‐diones.     

A Facile Synthesis of Raltegravir Potassium—An HIV Integrase Inhibitor

A facile, cost‐effective, and commercially viable synthesis of Raltegravir Potassium ( 1 ) has been developed from 2‐(1‐amino‐1‐methyl‐ethyl)‐N‐[(4‐fluorophenyl)methyl]‐1,6‐dihydro‐5‐hydroxy‐1‐methyl‐6‐oxo‐4‐pyrimidinecarboxamide ( 9 ) with high purity and in good yields. In addition, a new approach for the synthesis of key amine intermediate ( 9 ) of Raltegravir Potassium ( 1 ) from commercially available 2‐amino‐2‐methylpropanenitrile hydrochloride ( 2 ) is also described. The key features of the synthesis are fewer synthetic steps, employing the inexpensive reagents and eco‐friendly.