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11.
Highly regio- and stereoselective synthesis of glucosylspiro-oxindole/acenaphthenone derivatives was accomplished through 1,3-dipolar cycloaddition (1,3-DC) reaction. The glucosyl α,β-unsaturated-7,3-lactone (a sugar lactone) derived from d-glucose was used as a chiral dipolarophile in 1,3-DC reaction for the first time. The azomethine ylides generated from sarcosine/l-proline/thiazolidine-4-carboxylic acid/piperidine-2-carboxylic acid with isatin and acenaphthoquinone were trapped by the sugar lactone to give a series of glucosylspiro-pyrrolidine derivatives in good yields. 相似文献
12.
In this Letter we present small-angle neutron scattering data from a biomimetic system composed of the phospholipids dimyristoyl and dihexanoyl phosphorylcholine (DMPC and DHPC, respectively). Doping DMPC-DHPC multilamellar vesicles with either the negatively charged lipid dimyristoyl phosphorylglycerol (DMPG, net charge -1) or the divalent cation, calcium (Ca2+), leads to the spontaneous formation of energetically stabilized monodisperse unilamellar vesicles whose radii are concentration independent and in contrast with previous experimental observations. 相似文献
13.
We present the electron density map of the asymmetric ripple phase of dilauroylphosphatidylcholine. We find that the primary feature characterizing the "asymmetry" of the rippled bilayers is the difference in the bilayer thickness in the two arms, and not the asymmetry of the bilayer height profile as is generally assumed. This difference in the bilayer thickness can be attributed to a mean tilt of the hydrocarbon chains of the lipid molecules along the direction of the ripple wave vector. We propose a Landau theory for this phase which takes into account the anisotropic elastic properties of a bilayer with tilt order. 相似文献
14.
The synthesis of enantiomerically pure pyrano[4,5-c]pyrroles has been accomplished by the intramolecular hetero Diels–Alder reaction of enantiomerically pure N-allyltetheredalkenyl aldehydes with various 1,3-diones. The reaction led to the formation of cis-fused enantiomerically pure pyrano[4,5-c]pyrroles in excellent yield under mild conditions and the products were characterized by spectroscopic data. 相似文献
15.
J. Selvakumar V. S. Raghunathan K. S. Nagaraja 《Journal of Thermal Analysis and Calorimetry》2010,100(1):155-161
The volatile scandium-β-diketonates are synthesised using acetylacetone (acac) and tetramethylheptanedione (tmhd) as coordinative
ligands for CVD application. The X-ray powder patterns are indexed and analysed and found to be orthorhombic and monoclinic
phases for Sc(acac)3(1) and Sc(tmhd)3(2) respectively. The sublimation and evaporation kinetics have been analyzed using three calculating techniques. The non-isothermal
based activation energy values are found to be 38 ± 2 and 73 ± 2 kJ mol−1 by Flynn–Wall technique for (1) and (2) respectively. The measured Ea values are close to the value obtained using Kissinger method. 相似文献
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18.
C.S. Sundar Y. Hariharan A. Bharathi M. Premila V.S. Sastry G.V.N. Rao J. Janaki D.V. Natarajan K.V. Devadhasan T.S. Radhakrishnan N. Subramanian P.Ch. Sahu M. Yousuf S. Raju V.S. Raghunathan M.C. Valsakumar 《Progress in Crystal Growth and Characterization of Materials》1997,34(1-4):11-23
Amongst the other physical properties, the structure of fullerene solids, and the structural transformations with temperature, pressure and doping have all evoked considerable interest and during the last two years tremendous progress has been made in this area. This paper provides a brief review of the studies on the structural properties of pristine and doped fullerenes. The results of our own investigations are also presented. 相似文献
19.
V. Raghunathan P. S. Raghavan K. Vaidyanathan V. S. Srinivasan 《Journal of Chemical Sciences》1982,91(3):241-246
The chlorination of acetophenone by chloramine-T cat has been catalysed by anionic micelle, sodium lauryl sulphate (NaLS).
Though the order in cat is one, the order in acetophenone is fractional at lower concentration and becomes zero at higher
concentration in the presence and absence of NaLS. This is probably due to the change in rate-determining step. At lower acetophenone
concentration, the decomposition of enol-chlorinating species complex is rate-determining whereas at higher concentration,
the formation of chlorinating species is rate determining. The graph ofk
2 versus detergent concentration is sigmoidal and the positive co-operativityversus log[D] graph is 1.11, indicating possible interaction between micelle and substrate. 相似文献
20.
We prove that any principal bundle on the affine line over a perfect field with a reductive group as structure group comes
from the base field by base change. 相似文献