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31.
32.
Chandraprakash Kumarasamy Amsaveni Sundarasamy Sankaran Mathan Uvarani Chokkalingam Ata Athar Mohan Palathurai Subramaniam Suresh Thangaraj 《Journal of heterocyclic chemistry》2019,56(11):2986-2992
A one‐pot, multicomponent, convergent microwave synthesis of some new pyranyl‐ and chromenyl‐substituted quinolines has been reported. Twenty compounds were prepared by the reaction of 2‐methoxy‐3‐formyl quinoline ( 1a‐d ), malononitrile ( 2 ), and kojic acid ( 4a‐d )/1,3‐cyclohexadione or dimedone ( 6a ‐ h )/α‐ or β‐naphthol ( 8a ‐ d , 8e ‐ h ). The structures were confirmed by infrared (IR), 1H nuclear magnetic resonance (NMR), 13C NMR, mass, and single‐crystal X‐ray analyses. On comparison with the use of conventional Lewis acid catalysts and various metal triflates under microwave conditions, the latter contributed to good yields, in specific use of the recyclable Yb(OTf)3 catalyst attributed to high yields of the desired product. The protocol reported herein is solvent free, cost effective, and eco‐friendly. 相似文献
33.
Ludden MJ Mulder A Schulze K Subramaniam V Tampé R Huskens J 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(7):2044-2051
In this paper the multivalent binding of hexahistidine (His6)-tagged proteins to beta-cyclodextrin (beta-CD) self-assembled monolayers (SAMs) by using the nickel(II) complex of a hetero-divalent orthogonal adamantyl nitrilotriacetate linker (4) is described. Nonspecific interactions were suppressed by using monovalent adamantyl-hexa(ethylene glycol) derivative 3. With the mono-His6-tagged maltose binding protein (His6-MBP), thermodynamic modeling based on surface plasmon resonance (SPR) titration data showed that the MBP molecules in solution were linked, on average, to Ni.4 in 1:1 stoichiometry. On the surface, however, the majority of His(6)-MBP was complexed to surface-immobilized beta-CDs through three Ni.4 complexes. This difference is explained by the high effective beta-CD concentration at the surface and is a new example of supramolecular interfacial expression. In a similar adsorption scheme, SPR proved that the alpha-proteasome could be attached to beta-CD SAMs in a specific manner. Patterning through microcontact printing of (His6)4-DsRed-fluorescent timer (DsRed-FT), which is a tetrameric, visible autofluorescent protein, was carried out in the presence of Ni.4 Fluorescence measurements showed that the (His6)4-DsRed-FT is bound strongly through Ni.4 to the molecular printboard. 相似文献
34.
Subramaniam Gopalakrishnan Vijayabharathi Rajendran Sathya Arumugam Hari C. Sharma Srinivas Vadlamudi Ratna Kumari Bhimineni 《Natural product research》2016,30(24):2760-2769
Helicoverpa armigera, an important pest causes serious damage to grain legumes. The main objective of this study was to isolate and identify the metabolite against H. armigera from a previously characterised Streptomyces sp. CAI-155. The culture filtrate of CAI-155 was extracted using Diaion HP-20 and the active fractions were fractionated on Silica and C18 column chromatography. The C18 active fraction was further fractionated on Silica gel 60 F254 thin layer chromatography (TLC). The most active fraction (Rf 0.64) purified from TLC led to the identification of a novel metabolite N-(1-(2,2-dimethyl-5-undecyl-1,3-dioxolan-4-yl)-2-hydroxyethyl)stearamide by spectral studies. The purified metabolite showed 70–78% mortality in 2nd instar H. armigera by diet impregnation assay, detached leaf assay and greenhouse assay. The LD50 and LD90 values of the purified metabolite were 627 and 2276 ppm, respectively. Hence, this novel metabolite can be exploited for pest management in future. 相似文献
35.
Reynolds NP Janusz S Escalante-Marun M Timney J Ducker RE Olsen JD Otto C Subramaniam V Leggett GJ Hunter CN 《Journal of the American Chemical Society》2007,129(47):14625-14631
The precision placement of the desired protein components on a suitable substrate is an essential prelude to any hybrid "biochip" device, but a second and equally important condition must also be met: the retention of full biological activity. Here we demonstrate the selective binding of an optically active membrane protein, the light-harvesting LH2 complex from Rhodobacter sphaeroides, to patterned self-assembled monolayers at the micron scale and the fabrication of nanometer-scale patterns of these molecules using near-field photolithographic methods. In contrast to plasma proteins, which are reversibly adsorbed on many surfaces, the LH2 complex is readily patterned simply by spatial control of surface polarity. Near-field photolithography has yielded rows of light-harvesting complexes only 98 nm wide. Retention of the native optical properties of patterned LH2 molecules was demonstrated using in situ fluorescence emission spectroscopy. 相似文献
36.
37.
S. W. Chiu M. M. Clark Eric Jakobsson Shankar Subramaniam H. Larry Scott 《Journal of computational chemistry》1999,20(11):1153-1164
We describe a new equilibration procedure for the atomic level simulation of a hydrated lipid bilayer. The procedure consists of alternating molecular dynamics trajectory calculations in a constant surface tension and temperature ensemble with configurational bias Monte Carlo moves to different regions of the configuration space of the bilayer, in a constant volume and temperature ensemble. The procedure is described in detail and is applied to a bilayer of 100 molecules of dipalmitoyl phosphatidylcholine (DPPC) and 3205 water molecules. We find that the hybrid simulation procedure enhances the equilibration of the bilayer as measured by the convergence of the area per molecule and the segmental order parameters, as compared with a simulation using only molecular dynamics (MD). Progress toward equilibration is almost three times as fast in CPU time, compared with a purely MD simulation. Equilibration is complete, as judged by the lack of energy drift in three separate 200-ps runs of continuous MD started from different initial states. Results of the simulation are presented and compared with experimental data and with other recent simulations of DPPC. ©1999 John Wiley & Sons, Inc. J Comput Chem 20: 1153–1164, 1999 相似文献
38.
Juahir Yusnita Subramaniam Puvaneswary Hapipah Mohd. Ali Ward T. Robinson Thong Kwai-Lin 《Polyhedron》2009,28(14):3050-3054
2,6-Diacetylpyridine bis(benzenesulfonohydrazide) Schiff bases (L1, L2 and L3) and their Cu(II) complexes of the general formula [CuL·H2O] were synthesized and characterized by various spectroscopic techniques. The crystal structure of [CuL3·(py)]·py was investigated by single crystal X-ray structure analysis. The Cu(II) cation has near square pyramidal, penta-coordinate geometry. The binegatively charged tetradentate Schiff base is asymmetrically coordinated to the Cu(II) ion via the pyridine N atom, the azomethine N atom, the sulfonyl O atom and the deprotonated hydrazine N atom. There is a pyridine molecule apically coordinated to the Cu(II) ion. All the Schiff bases and their copper(II) complexes were screened by the disc diffusion method against multi-drug resistant (MDR) gram-negative and gram-positive bacteria. The minimum inhibitory concentration (MIC) values were also determined. These results show that the antibacterial activity of the Schiff bases against Methicillin-resistant Staphylococcus aureus (MRSA) is enhanced when they are chelated with the copper(II) ion. 相似文献
39.
Synthesis, characterization and radiolytic properties of bis(oxalato)borate containing ionic liquids
Sharon I. Lall-Ramnarine Alejandra Castano Gopal Subramaniam Marie F. Thomas James F. Wishart 《Radiation Physics and Chemistry》2009,78(12):1120-1125
Previously unreported bis(oxalato)borate (BOB) ionic liquids (ILs) containing imidazolium, pyridinium, and pyrrolidinium cations were prepared from the corresponding halide salts by reaction with sodium bis(oxalato)borate (NaBOB), and their properties are reported. Pulse radiolysis experiments revealed that the BOB anion scavenges solvated electrons with rate constants of 3×108 M−1 s−1 in the ionic liquid C4mpyrr NTf2 and 2.8×107 M−1 s−1 in water. This reactivity indicates that BOB ILs may be too sensitive to be used as neat solvents for nuclear separations processes in high radiation fields but may still be useful for preventing criticality while processing relatively “cold” fissile actinides. 相似文献
40.
The discovery and use of fluorescent proteins has revolutionized cellular biology. Despite the widespread use of visible fluorescent
proteins as reporters and sensors in cellular environments the versatile photophysics of fluorescent proteins is still subject
to intense research. Understanding the details of the photophysics of these reporters is essential for accurate interpretation
of the biological and biochemical processes illuminated by fluorescent proteins. Some aspects of the complex photophysics
of fluorescent proteins can only be observed and understood at the single-molecule level, which removes averaging inherent
to ensemble studies. In this paper we review how single-molecule emission detection has helped understanding of the complex
photophysics of fluorescent proteins.
相似文献
Vinod SubramaniamEmail: |