- L-Proline supported on ionic liquid-modified magnetic nanoparticles as a highly efficient and reusable organocatalyst for direct asymmetric aldol reaction in water
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Grafting l-proline on imidazolium-based ionic liquid (IL)-functionalized magnetic nanoparticles afforded a magnetically recoverable l-proline catalyst. Characterization technologies suggested the presence of an l-proline backbone, an IL linker, and a magn
- Kong, Yu,Tan, Rong,Zhao, Lili,Yin, Donghong
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- Influence of calcium-induced aggregation on the sensitivity of aminobis(methylenephosphonate)-containing potential MRI contrast agents
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A novel class of 1,4,7,10-tetraazacyclododecane-1,4,7- tris(methylenecarboxylic) acid (DO3A)-based lanthanide complexes with relaxometric response to Ca2+ was synthesized, and their physicochemical properties were investigated. Four macrocyclic ligands containing an alkyl-aminobis(methylenephosphonate) side chain for Ca 2+-chelation have been studied (alkyl is propyl, butyl, pentyl, and hexyl for L1, L2, L3, and L4, respectively). Upon addition of Ca2+, the r1 relaxivity of their Gd3+ complexes decreased up to 61% of the initial value for the best compounds GdL3 and GdL4. The relaxivity of the complexes was concentration dependent (it decreases with increasing concentration). Diffusion NMR studies on the Y3+ analogues evidenced the formation of agglomerates at higher concentrations; the aggregation becomes even more important in the presence of Ca2+. 31P NMR experiments on EuL1 and EuL4 indicated the coordination of a phosphonate to the Ln3+ for the ligand with a propyl chain, while phosphonate coordination was not observed for the analogue bearing a hexyl linker. Potentiometric titrations yielded protonation constants of the Gd 3+ complexes. log KH1 values for all complexes lie between 6.12 and 7.11 whereas log KH2 values are between 4.61 and 5.87. Luminescence emission spectra recorded on the Eu3+ complexes confirmed the coordination of a phosphonate group to the Ln3+ center in EuL1. Luminescence lifetime measurements showed that Ca-induced agglomeration reduces the hydration number which is the main cause for the change in r1. Variable temperature 17O NMR experiments evidenced high water exchange rates on GdL1, GdL2, and GdL3 comparable to that of the aqua ion.
- Henig, Joerg,Mamedov, Ilgar,Fouskova, Petra,Toth, Eva,Logothetis, Nikos K.,Angelovski, Goran,Mayer, Hermann A.
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p. 6472 - 6481
(2011/08/07)
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- Expedient protocol for solid-phase synthesis of secondary and tertiary amines
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Equation presented. An expedient solid-phase synthetic approach to secondary and tertiary amines was developed. The protocol employs conversion of resin-bound amino alcohols to the corresponding iodides, followed by iodide displacement with primary or sec
- Olsen, Christian A.,Witt, Matthias,Jaroszewski, Jerzy W.,Franzyk, Henrik
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p. 1935 - 1938
(2007/10/03)
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- PHTHALIMIDO ARYLPIPERAZINES USEFUL IN THE TREATMENT OF BENIGN PROSTATIC HYPERPLASIA
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This invention relates to a series of substituted piperazines of Formula II, as well as enantiomers thereof These compounds are useful in the manufacture of pharmaceutical compositions.
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- FURAN DERIVATIVES HAVING ANTI-ULCER ACTIVITY
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Compounds of formula (I): STR1 wherein: A represents a CH-NO 2 group or a N-CN group;B represents CH 2, O, S or a direct bond;R represents a bicyclic or polycyclic residue, variously substituted and functionalized;R 1 and R 2, which may be the same or different, are hydrogen or C 1-C 4 alkyl groups; andn and m, which may be the same or different, are 0, 1, 2, 3 or 4; are valuable pharmacological agents.
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