- Synthesis and structure of environmentally relevant perfluorinated sulfonamides
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Alkylated perfluorooctanesulfonamides are compounds of environmental concern. To make these compounds available for environmental and toxicological studies, a series of N-alkylated perfluorooctanesulfonamides and structurally related compounds were synthesized by reaction of the corresponding perfluoroalkanesulfonyl fluoride with a suitable primary or secondary amine. Perfluoroalkanesulfonamidoethanols were obtained from the N-alkyl perfluoroalkanesulfonamides either by direct alkylation with bromoethanol or alkylation with acetic acid 2-bromo-ethyl ester followed by hydrolysis of the acetate. N-Alkyl perfluorooctanesulfonamidoacetates were synthesized in an analogous way by alkylation of N-alkyl perfluoroalkanesulfonamides with a bromo acetic acid ester, followed by basic ester hydrolysis. Alternatively, N-alkyl perfluoroalkanesulfonamides can be alkylated with an appropriate alcohol using the Mitsunobu reaction. Perfluorooctanesulfonamide was synthesized from the perfluorooctanesulfonyl fluoride via the azide by reduction with Zn/HCl. All perfluorooctanesulfonamides contained linear as well as branched C8F17 isomers, typically in a 10:1 to 30:1 ratio. The crystal structures of N-ethyl and N,N-diethyl perfluorooctanesulfonamide show that the S-N bond has considerable double bond character. This double bond character results in a significant rotational barrier around the S-N bond (ΔG≠ = 62-71 kJ mol-1) and a preferred solid state and solution conformation in which the N-alkyl groups are oriented opposite to the perfluorooctyl group to minimize steric crowding around the S-N bond.
- Lehmler, Hans-Joachim,Rama Rao,Nauduri, Dhananjaya,Vargo, John D.,Parkin, Sean
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p. 595 - 607
(2008/02/07)
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- Oligomeric compounds that contain perfluoroalkyl, process for their production, and their use in NMR diagnosis
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Oligomeric compounds that contain perfluoroalkyl of general formula IA-RF(I)in which A is a molecule portion that contains 2-6 metal complexes that are connected directly or via a linker to a nitrogen atom of an annular skeleton chain, and RF is a perfluorinated, straight-chain or branched carbon chain with formula -CnF2nE, in which E represents a terminal fluorine, chlorine, bromine, iodine, or hydrogen atom and n stands for numbers 4-30, are valuable compounds for diagnosis, especially as in-vivo contrast media.
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