- Synthesis of novel amphiphilic spin probes with the paramagnetic doxyl group in the polar region
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The use of ESR and specially designed spin probes has led to major breakthroughs in understanding the complexity of biological membranes. Research has been focused mainly on molecular events within the?lipid bilayer, and few probes have been designed for studying events in the extracellular space near the membrane surface. We have prepared a series of amphiphilic spin probes in which an ethylene glycol type hydrophilic spacer was introduced between a hydrophobic anchor and the doxyl group, placing the latter above the membrane in the extracellular space. Furthermore, the 2pπ orbital, containing the unpaired electron of the nitroxide group, would be orientated perpendicular to the membrane surface, making it more useful for ESR investigations of structural and dynamic properties close to the membrane surface in different situations of the cell life.
- Pajk, Stane,Pe?ar, Slavko
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scheme or table
p. 659 - 665
(2009/04/07)
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- Combinatorial synthesis of PEG oligomer libraries
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A simple chain-extending approach was established for the scale-up of the monoprotected monodisperse PEG diol materials. Reactions of THP-(OCH2CH2)n—OMs (n=4, 8, 12) with a large excess of commercially available H—(OCH2CH2)n—OH (n=1-4) under basic conditions led to THP-(OCH2CH2)n—OH (n=5-15). Similarly, Me-(OCH2CH2)n—OH (n=4-11, 13) were prepared from Me-(OCH2CH2)n—OMs (n=3, 7, 11). For the chain elongation steps, 40-80% yields were achieved through extraction purification. PEG oligomer libraries I and II were generated in 50-95% overall yields by alkylation or acylation of THP-(OCH2CH2)n—OH (n=1-15) followed by deprotection. Alkylation of Me-(OCH2CH2)n—OH (n=1-11, 13) with X—(CH2)m—CO2R (X=Br or OMs) and subsequent hydrolysis led to PEG oligomer library III in 30-60% overall yields. Combinatorial purification techniques were adapted to the larger-scale library synthesis. A total of 498 compounds, each with a weight of 2-5 g and a minimum purity of 90%, were synthesized.
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Page/Page column 11
(2010/02/15)
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