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261.
Santosh Kumar Joonseok Koh Dilip Kumar Tiwari Pradip Kumar Dutta 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(10):789-795
Chitosan ofloxacin complex was prepared in isopropyl alcohol under mild conditions. The ionic complexation between chitosan and ofloxacin was confirmed by Fourier transform infrared (FTIR), and nuclear magnetic resonance (NMR) spectroscopy. The crystallinity, thermal, surface morphology and optical properties were evaluated by X-ray diffraction (XRD) analysis, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), ultraviolet-visible (UV-Vis) spectroscopy, photoluminescence (PL) spectroscopy and second harmonic generation (SHG) studies, respectively. Absorption of the complex was high (106cm?1) with an optical band gap of 3.80 eV. The chitosan-ofloxacin complex may be considered as a novel optical material from biomedical application point of views. It may find applications as biosensors and environmentally sensitive membranes and artificial membranes. 相似文献
262.
Shyam Babu Singh Kamleshwar Tiwari Pankaj Kumar Verma Madhulika Srivastava Kamla Prasad Tiwari 《Supramolecular chemistry》2013,25(5):255-262
Novel spiro-oxindole derivatives were synthesised by one-pot multicomponent reaction using isatins, urea and 1,3-dicarbonyls. β-Cyclodextrin, an oligosaccharide, catalysed the reaction and can be reused for further reaction after recovery. This developed synthetic route is environmentally benign in which water is used as solvent to produce excellent yields of products. The synthesised compounds were evaluated for their antimicrobial activities against two bacteria and two fungi. All the synthesised spiro-oxindoles exhibit significant antimicrobial activity. 相似文献
263.
Shyam Babu Singh Pankaj Kumar Verma Kamleshwar Tiwari Mandavi Singh Preyas Ankit Shahin Fatma 《合成通讯》2014,44(12):1795-1802
An efficient triphenylphosphine-catalyzed synthesis of β-acetamido carbonyls via multicomponent reaction of aromatic aldehydes, enolizable ketones or β-keto esters, acid chlorides and acetonitrile at room temperature is described. The process is remarkably simple, environmentally benign, and uses Lewis base for the first time in such type of reaction. 相似文献
264.
Brijesh Pandey Veda P. Pandey A. K. Shasany U. N. Dwivedi 《Applied biochemistry and biotechnology》2014,172(7):3414-3423
A cinnamyl alcohol dehydrogenase (CAD) from the secondary xylem of Leucaena leucocephala has been purified to homogeneity through successive steps of ammonium sulfate fractionation, DEAE cellulose, Sephadex G-75, and Blue Sepharose CL-6B affinity column chromatographies. CAD was purified to 514.2 folds with overall recovery of 13 % and specific activity of 812. 5 nkat/mg. Native and subunit molecular masses of the purified enzyme were found to be ~76 and ~38 kDa, respectively, suggesting it to be a homodimer. The enzyme exhibited highest catalytic efficiency (Kcat/Km 3.75 μM?1 s?1) with cinnamyl aldehyde among all the substrates investigated. The pH and temperature optima of the purified CAD were pH 8.8 and 40 °C, respectively. The enzyme activity was enhanced in the presence of 2.0 mM Mg2+, while Zn2+ at the same concentration exerted an inhibitory effect. The inclusion of 2.0 mM EDTA in the assay system activated the enzyme. The enzyme was inhibited with caffeic acid and ferulic acid in a concentration-dependent manner, while no inhibition was observed with salicylic acid. Peptide mass analysis of the purified CAD by MALDI-TOF showed a significant homology to alcohol dehydrogenases of MDR superfamily. 相似文献
265.
Juwar Doley Lakshya Veer Singh G. Ravi Kumar Aditya Prasad Sahoo Lovleen Saxena Uttara Chaturvedi Shikha Saxena Rajiv Kumar Prafull Kumar Singh R. S. Rajmani Lakshman Santra S. K. Palia S. Tiwari D. R. Harish Arvind Kumar G. S. Desai Smita Gupta Shishir K. Gupta A. K. Tiwari 《Applied biochemistry and biotechnology》2014,172(1):497-508
The canine parvovirus type 2 (CPV-2) causes an acute disease in dogs. It has been found to induce cell cycle arrest and DNA damage leading to cellular lysis. In this paper, we evaluated the apoptotic potential of the “new CPV-2a” in MDCK cells and elucidated the mechanism of the induction of apoptosis. The exposure of MDCK cells to the virus was found to trigger apoptotic response. Apoptosis was confirmed by phosphatidylserine translocation, DNA fragmentation assays, and cell cycle analysis. Activation of caspases-3, -8, -9, and -12 and decrease in mitochondrial potential in CPV-2a-infected MDCK cells suggested that the CPV-2a-induced apoptosis is caspase dependent involving extrinsic, intrinsic, and endoplasmic reticulum pathways. Increase in p53 and Bax/Bcl2 ratio was also observed in CPV-2a-infected cells. 相似文献
266.
Somayeh Motavallizadeh Asal Fallah-Tafti Saeedeh Maleki Amir Nasrolahi Shirazi Mahboobeh Pordeli Maliheh Safavi Sussan Kabudanian Ardestani Shaaban Asd Rakesh Tiwari Donghoon Oh Abbas Shafiee Alireza Foroumadi Keykavous Parang Tahmineh Akbarzadeh 《Tetrahedron letters》2014
Several novel N-(9-oxo-9H-xanthen-4-yl)benzenesulfonamide derivatives were prepared as potential antiproliferative agents. The in vitro antiproliferative activity of the synthesized compounds was investigated against a panel of tumor cell lines including breast cancer cell lines (MDA-MB-231, T-47D) and neuroblastoma cell line (SK-N-MC) using MTT colorimetric assay. Etoposide, a well-known anticancer drug, was used as a positive standard drug. Among synthesized compounds, 4-methoxy-N-(9-oxo-9H-xanthen-4-yl)benzenesulfonamide (5i) showed the highest antiproliferative activity against MDA-MB-231, T-47D, and SK-N-MC cells. Furthermore, pentafluoro derivatives 5a and 6a exhibited higher antiproliferative activity than doxorubicin against human leukemia cell line (CCRF-CEM) and breast adenocarcinoma (MDA-MB-468) cells. Structure–activity relationship studies revealed that xanthone benzenesulfonamide hybrid compounds can be used for the development of new lead anticancer agents. 相似文献
267.
In the present paper, we have executed the synthesis of substituted 5-(2-chloroquinolin-3-yl)-3-phenyl-4,5-dihydroisoxazolines via the reactions of substituted 3-(2-chloroquinolin-3-yl)-1-phenylprop-2-en-1-ones with hydroxylamine hydrochloride and sodium acetate in aqueous acetic acid solution in 72-90% yields at room temperature under ultrasound irradiation. This method provides several advantages such as operational simplicity, higher yield, safety and environment friendly protocol. The resulting substituted isoxazolines were characterized on the basis of (1)H NMR, (13)C NMR, IR, elemental analysis, and mass spectral data. 相似文献
268.
269.
Keshri Nath Tiwari Snehal Rajendra Thakar Vaneet Kumar S. M. Prabhakaran 《合成通讯》2013,43(23):2965-2972
An easy protocol for the synthesis of enaminone attached 3-substituted-3-hydroxy-2-oxindoles has been demonstrated by reaction of isatin and cyclic enaminone in water. The developed catalyst-free reaction has the advantage of being atom-economical, eco-friendly, and benign reaction conditions. The broader substrate scope, experimentally simple procedures, and easy purification of products with high yield further make this method attractive and useful. 相似文献
270.
Recently we reported an efficient synthesis of the berbine alkaloids3,4 by the use of the bromo esters5 prepared from 3-isochromanones. Now a new general synthetic route to the berbine alkaloids beginning with the condensation of the phenethylbromide 3 and 3-(2H) isoquinolone 2 is being described. The method gains added advantage of placing desired substitution on both rings A and D of the berbine, emerging from the easy availability of the starting compounds. In conclusion, the present results have not only added one more efficient example to more than a dozen successful procedures of the berbine synthesis6 but also offer a potential route to the structurally parallel indoloquinolizidine alkaloids. 相似文献