50889-47-9Relevant academic research and scientific papers
Amines that transport protons across bilayer membranes: Synthesis, lysosomal neutralization, and two-phase pKa values by NMR
Dubowchik, Gene M.,Padilla, Linda,Edinger, Kurt,Firestone, Raymond A.
, p. 4676 - 4684 (1996)
It is desirable to be able to control the pH of lysosomes. A collection of lipophilic, nitrogenous bases, designed to act as membrane-active, catalytic proton transfer agents, were prepared and their effective pKas measured in a vigorously stirred, two-phase system. One phase was a phosphate buffer whose pH was varied over the range ca. 1-11. The other was an immiscible, deuterated organic solvent in which the compounds preferentially resided even when protonated. When chemical shift changes versus the pH of the buffer were plotted, clear pKa curves were generated that are relevant to transmembrane proton transfer behavior. The two-phase pKas increased with increasing counterion lipophilicity and with increasing organic solvent polarity. The compounds were also tested for their ability to neutralize the acidity of lysosomes, a model for other acidic vesicles involved in drug sorting. The most successful of these, imidazole 6a, has > 100 times the neutralizing power of ammonia, a standard lysosomotropic amine, causing a 1.7 unit rise in lysosomal pH of RAW cells at 0.1 mM, compared to a 0.2 and 1.4 unit rise for ammonium chloride at 0.1 and 10 mM, respectively.
Absolute rate constants for radical additions to alkenes in solution. The synergistic effect of perfluorination on the reactivities of n-alkyl radicals
Avila, David V.,Ingold,Lusztyk,Dolbier Jr.,Pan
, p. 2027 - 2030 (1996)
Laser flash photolysis has been used to determine the absolute rate constants for addition of several partially fluorinated n-alkyl radicals to three styrenes at 25°C in Freon 113. Fluorination at the γ-position (RCF2CH2CH2?) gives radicals with essentially the same reactivity as non-fluorinated n-alkyls. The RCH 2CF2CH2? and RCH2CH 2CHF? radicals are both about three times as reactive as RCF2CH2CH2?, but the RCH 2CH2CF2? radical is ca. five to six times rather than ca. three times as reactive as RCH2CH2CHF?. Similarly, the perfluorinated radical CF3CF2CF 2? is much more reactive than would be expected on the basis of the reactivities of the RCH2CF2CH2? and RCH2CH2CF2? radicals. Thus, perfluorinated n-alkyl radicals are very considerably more reactive than would be predicted from the individual effects of α, β-, and γ-fluorination.
