VOLUME 67, NUMBER 20
OCTOBER 4, 2002
© Copyright 2002 by the American Chemical Society
Syntheses and Reactivities of Disubstituted and Trisubstituted Fluorous Pyridines with High Fluorous Phase Affinities: Solid State, Liquid Crystal, and Ionic Liquid-Phase Properties Christian Rocaboy, Frank Hampel, and J. A. Gladysz* Institut fu¨ r Organische Chemie, Friedrich-Alexander Universita¨ t Erlangen-Nu¨ rnberg, Henkestrasse 42, 91054 Erlangen, Germany
[email protected] Received December 21, 2001
Reactions of 2,6-dibromo-, 3,5-dibromo-, and 2,4,6-tribromopyridine with IZnCH2CH2Rf8 (Rf8 ) (CF2)7CF3) in THF at 65 °C in the presence of trans-Cl2Pd(PPh3)2 (5 mol %) gave the fluorous pyridines 2,6- and 3,5-NC5H3(CH2CH2Rf8)2 (1 and 2; 85%, 31%) and 2,4,6-NC5H2(CH2CH2Rf8)3 (3, 61%). Reaction of 2,6-pyridinedicarboxaldehyde with [Ph3PCH2CH2Rf8]+I-/K2CO3 (p-dioxane/H2O, 95 °C) gave 2,6-NC5H3(CHdCHCH2Rf8)2 (95%; 70:30 ZZ/ZE), which was treated with H2 (1 atm, 12 h) and 10% Pd/C to yield 2,6-NC5H3(CH2CH2CH2Rf8)2 (5, 95%), a higher homologue of 1. Longer reaction times afforded piperidine cis-2,6-HNC5H8(CH2CH2CH2Rf8)2 (6, 98%). The stereochemistry was established by NMR analysis of the N-benzylpiperidine. Pyridines 1-3 and 5 are low-melting white solids with CF3C6F11/toluene partition coefficients (24 °C) of 93.8:6.2, 93.9:6.1, >99.7:99.7:99.7:90:99.7:
