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161.
Chiranjeevi Bingi Kaushik Yadav Kola Ashok Kale Jagadeesh Babu Nanubolu Krishnaiah Atmakur 《Tetrahedron letters》2017,58(11):1071-1074
Synthesis of a series of tricyclic quinazolinones have been accomplished starting from anthranilamide and 1,3-cyclic dione promoted by TsOH·H2O The protocol presented herein based on retro-Dieckmann type reaction, leading to incorporation of dione as an acyclic unit into the product. Simple reaction conditions, broad scope, excellent yields are the advantages of this protocol. Further, this methodology is extended to the synthesis of pyridopyrimidinones and benzimidazopyridines. 相似文献
162.
Yadav RA Mukherjee V Kumar M Singh R 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2007,66(4-5):964-971
Force field calculations have been carried out for the planar and non-planar modes of pyrazine-N,N′-O2 using the observed vibrational frequencies obtained from the IR and Raman spectral studies on pyrazine-N,N′-O2-h4 and pyrazine-N,N′-O2-d4 reported in the literature [D.A. Thornton, P.F.M. Verhoeven, G.M. Watkins, Herman O. Desseyn, Benjamin J. Van der Veken, Spectrochim. Acta 46A (1990) 1439]. The purpose of the present work is to determine force fields for the pyrazine-N,N′-O2 molecule and to present vibrational assignments for the observed IR and Raman frequencies to the fundamental modes, combination bands and overtones. The planar force field determined in the present case is expected to be better than that reported earlier [S. Szöke, G. Varsanyi, E. Baitz, Acta Chim. 53 (1967) 345] because of the inclusion of the observed frequencies due to pyrazine-N,N′-O2-d4 isotopomer. In addition, the non-planar force field for this molecule is reported for the first time. 相似文献
163.
Samson Rwawiire Blanka Tomkova Jiri Militky Bandu Madhukar Kale Petr Prucha 《International Journal of Polymer Analysis and Characterization》2015,20(2):160-171
The quest for sustainable materials as a consequence of a global drive to mitigate climate change has led to a focus on natural fiber–reinforced composite materials. In this study, skillful ply angle arrangement of bark cloth–reinforced laminar epoxy composites was carried out for the first time using vacuum-assisted resin transfer molding, and the composites fabricated were characterized for the effect of the layering pattern on their static and dynamic mechanical properties. Tensile strength and flexural strength were shown to be dependent on the ply angle arrangement. Dynamic mechanical analysis of the composites showed a glass transition temperature of 70°C, and the storage modulus and mechanical damping properties showed that the developed composites can withstand considerable loads and have excellent fiber-to-matrix adhesion. 相似文献
164.
Two clusters with a new type of Fe(III)(7) disklike structure have been prepared; in contrast to other Fe(III)(7) disks, they possess high ground-state spins (S = (15)/(2) and (21)/(2)), which have been rationalized by analysis of the spin-frustration patterns. 相似文献
165.
Tewari AK Singh VP Dubey R Puerta C Valerga P Verma R 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,79(5):1267-1275
The structure of 1,3-bis(4,6-dimethyl-1H-nicotinonitrile-1-yl)1,3-dioxy propane polymorphs has been characterized by X-ray diffraction, FT-IR, 1H and 13C NMR spectroscopies. The influence of intra and intermolecular weak interactions is thoroughly studied in solid state using single crystal X-ray diffraction and FT-IR. These polymorphs belong to monoclinic space group 'P2(1/n)' and 'P2(1/c)'. These polymorphs have C-H?n (lone pair), hydrogen bonds, C-N?π, C-H?π and π?π intermolecular non-covalent interactions. These polymorphs are the result of weak interactions and solvent used in crystallization. The FT-IR spectra have been recorded in the solid phase and NMR has been recorded in solvent. The optimized geometry has been calculated by B3LYP methods using different basis sets. The FT-IR and NMR spectra of 1st polymorphs has been calculated at B3LYP/6-31G (d) level. The scaled theoretical wave number showed good agreement with the experimental values. These two polymorphs as well as other stereomers are studied by DFT calculations. 相似文献
166.
In the present study also a superparamagnetic nanocomposite of Poly (vinyl- alcohol-g-acrylonitrile) has been designed by homogeneous impregnation of iron oxide nanoparticles into the graft polymer matrix. The so prepared nanocomposite was characterized by FT-IR, TEM and XRD techniques and studied for water sorption behavior and magnetization properties. The superparamagnetic nanocomposite was loaded with an antibiotic drug, ciprofloxacin (CFx), and its release behavior was investigated under varying experimental conditions such as chemical composition of the matrix, pH of the release media, applied magnetic field and percent loading of the drug. The drug transport mechanism was also analyzed using Ficks power law. The drug loaded magnetic nanocomposite was also studied for antibacterial and in-vitro blood compatible properties. 相似文献
167.
168.
Kulkarni RV Boppana R Krishna Mohan G Mutalik S Kalyane NV 《Journal of colloid and interface science》2012,367(1):509-517
In the present work, we synthesized pH-responsive interpenetrating network (IPN) hydrogel beads of polyacrylamide grafted κ-carrageenan (PAAm-g-CG) and sodium alginate (SA) for targeting ketoprofen to the intestine. The PAAm-g-CG was synthesized by free radical polymerization followed by alkaline hydrolysis under nitrogen gas. The PAAm-g-CG was characterized by elemental analysis, FTIR spectroscopy and thermogravimetric analysis (TGA). The drug-loaded IPN hydrogel beads were prepared by simple ionotropic gelation/covalent crosslinking method. The amorphous nature of drug in the beads was confirmed by differential scanning calorimetry and X-ray diffraction studies. The spherical shape of the beads was confirmed by scanning electron microscopic analysis. The beads exhibited ample pH-responsive behavior in the pulsatile swelling study. The ketoprofen release was significantly increased when pH of the medium was changed from acidic to alkaline. The beads showed maximum of 10% drug release in acidic medium of pH 1.2, and about 90% drug release was recorded in alkaline medium of pH 7.4. Stomach histopathology of albino rats indicated that the prepared beads were able to retard the drug release in stomach leading to the reduced ulceration, hemorrhage and erosion of gastric mucosa. 相似文献
169.
Tsai YF Shih CH Su YT Yao CH Lian JF Liao CC Hsia CW Shui HA Rani R 《Organic & biomolecular chemistry》2012,10(5):931-934
The total synthesis of ganglioside 2, an analogue of the ganglioside Hp-s1 (1) which displays neuritogenic activity toward the rat pheochromocytoma cell line PC-12 cell in the presence of nerve growth factor (NGF) with an effect (34.0%) greater than that of the mammalian ganglioside GM 1 (25.4%), was accomplished by applying a chemoselective-activation glycosylation strategy. Moreover, we also demonstrate that the synthesized ganglioside 2 exhibited neuritogenic activity toward the human neuroblastoma cell line SH-SY5Y without the presence of NGF. 相似文献
170.
Shamrao T. Disale Sandip R. Kale Sandeep S. Kahandal Thandankorai G. Srinivasan Radha V. Jayaram 《Tetrahedron letters》2012,53(18):2277-2279
The choline based Zn containing deep eutectic mixture was applied as an efficient and eco-friendly ionic liquid catalyst for the one pot three-component synthesis of α-aminophosphonates under solvent-free condition at room temperature. The reactions were completed in short times and products were obtained in good to excellent yields. 相似文献