S. Kim, K.M. Miller / Polymer 53 (2012) 5666e5674
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2.5. Synthesis of 1,3-bis(20-acetoacetoxyethyl)imidazolium
bis(trifluoromethylsulfonyl)imide 8
135.94, 167.26, 201.66. HR MS (MALDI-TOF, m/z): [MꢀNO3]þ
calculated for C23H37N2O6, 437.2652; found, 437.2655.
2.8. Synthesis of 1,3-bis(60-acetoacetoxyhexyl)imidazolium
bis(trifluoromethylsulfonyl)imide 11
To a 25 mL round-bottomed flask equipped with a magnetic stir
bar was dissolved 1,3-bis(20-acetoacetoxyethyl)imidazolium bromide
7 (0.50 g, 1.23 mmol) in deionized water (5 mL). To this stirred
solution was added a solution of lithium bis(trifluoromethylsulfonyl)
imide (0.37 g, 1.25 mmol) in deionized water (5 mL). After several
minutes, an orange oil was observed at the bottom of the flask.
Chloroform (5 mL) was added to the flask and the mixture was
stirred vigorously at room temperature overnight. The organic phase
was then separated, washed twice with DI water and the solvent
To a 50 mL round-bottomed flask equipped with a magnetic stir
bar was dissolved 1,3-bis(60-acetoacetoxyhexyl)imidazolium bromide
8 (2.50 g, 4.83 mmol) in chloroform (20 mL). To this stirred solution
was added a solution of lithium bis(trifluoromethylsulfonyl)imide
(1.46 g, 5.07 mmol) in deionized water (5 mL). The mixture was
vigorously stirred overnight at room temperature. The organic phase
was separated, washed twice with DI water and then the solvent was
removed under reduced pressure to afford 3.23 g (93%) of a light
removed under reduced pressure to afford 0.68 g (91%) of the target
1
compound as a light yellow oil. H NMR (DMSO-d6):
d 2.14 (s, 6H,
yellow oil. 1H NMR (DMSO-d6):
d 1.21e1.40 (m, 8 H, CH2), 1.57 (m, 4H,
CH2), 1.79 (m, 4H, CH2), 2.17 (s, 6H, CH3), 3.59 (s, 4H, CH2 on AcAc
CH3), 3.64 (s, 4H, CH2 on AcAc group), 4.45 (m, 8H), 7.79 (s, 2H, Are
H
4,5), 9.15 (s, 1H, AreH2). 13C NMR (DMSO-d6):
d
30.03, 48.06, 49.35,
62.49,119.54 (q, J ¼ 308 Hz, CF3),122.76,137.18,166.94, 201.71. HR MS
(MALDI-TOF, m/z): [MꢀNTf2]þ calculated for C15H21N2O6, 325.1400;
found, 325.1401.
group), 4.04 (t, J ¼ 7 Hz, 4H, AcAcOeCH2), 4.15 (t, J ¼ 7 Hz, 4H, NeCH2),
7.79 (s, 2H, AreH4,5), 9.17 (s, 1H, AreH2). 13C NMR (DMSO-d6):
d 25.05,
27.75, 29.14, 30.09, 48.76, 49.57, 64.21, 119.49 (q, J ¼ 322 Hz, CF3),
122.43, 135.92, 167.30, 201.61. HR MS (MALDI-TOF, m/z): [MeNTf2]þ
calculated for C23H37N2O6, 437.2652; found, 437.2661.
2.6. Synthesis of 1,3-bis(60-acetoacetoxyhexyl)imidazolium
trifluoroacetate 9
2.9. Synthesis of 1,3-bis(60-acetoacetoxyhexyl)imidazolium
tetrafluoroborate 12
To a 25 mL round-bottomed flask equipped with a magnetic stir
bar was dissolved 1,3-bis(60-acetoacetoxyhexyl)imidazolium
bromide 8 (1.50 g, 2.9 mmol) in DI water (8 mL). To this stirred
solution was added silver trifluoroacetate (0.70 g, 3.2 mmol), dis-
solved in DI water (2 mL). The resulting mixture (a precipitate
formed immediately) was vigorously stirred overnight at room
temperature. The mixture was then filtered and extracted with
ethyl acetate. The organic phase was separated, washed twice with
DI water and the solvent was removed under reduced pressure to
To a 50 mL round-bottomed flask equipped with a magnetic stir
bar was dissolved 1,3-bis(60-acetoacetoxyhexyl)imidazolium
bromide 8 (3.00 g, 5.79 mmol) in acetone (30 mL). To this stirred
solution was added sodium tetrafluoroborate (0.67 g, 6.09 mmol).
Precipitate formation was observed within 30 min of stirring at
room temperature. The mixture was allowed to continue to stir
overnight. The solids were then filtered and solvent removed under
reduced pressure. The residue was dissolved in chloroform, washed
twice with DI water and solvent removed under reduced pressure,
resulting in 2.59 g (85%) of a light yellow oil. 1H NMR (DMSO-d6):
afford 1.35 g (84%) of a yellow oil. 1H NMR (DMSO-d6):
d 1.20e1.40
(m, 8H, CH2), 1.56 (m, 4H, CH2), 1.78 (m, 4H, CH2), 2.17 (s, 6H, CH3),
3.59 (s, 4H, CH2 on AcAc group), 4.03 (t, J ¼ 7 Hz, 4H, AcAcOeCH2),
4.15 (t, J ¼ 7 Hz, 4H, NeCH2), 7.80 (s, 2H, AreH4,5), 9.20 (s, 1H, Are
d
1.21e1.39 (m, 8 H, CH2), 1.57 (m, 4H, CH2), 1.79 (m, 4H, CH2), 2.17
(s, 6H, CH3), 3.58 (s, 4H, CH2 on AcAc group), 4.03 (t, J ¼ 7 Hz, 4H,
H2). 13C NMR (DMSO-d6):
d 24.56, 25.06, 27.77, 29.14, 48.76, 49.58,
AcAcOeCH2), 4.14 (t, J ¼ 7 Hz, 4H, NeCH2), 7.79 (s, 2H, AreH4,5), 9.17
64.22, 117.23 (q, J ¼ 300 Hz, CF3), 122.46, 135.93, 167.27, 201.63. HR
MS (MALDI-TOF, m/z): [MeCF3CO2]þ calculated for C23H37N2O6,
437.2652; found, 437.2647.
(s, 1H, AreH2). 13C NMR (DMSO-d6):
d 25.01, 27.70, 29.05, 29.99,
48.73, 49.54, 64.10, 122.48, 135.83, 167.37, 201.62. HR MS (MALDI-
TOF, m/z): [MꢀBF4]þ calculated for C23H37N2O6, 437.2652; found,
437.2653.
2.7. Synthesis of 1,3-bis(60-acetoacetoxyhexyl)imidazolium nitrate 10
2.10. Synthesis of 1,6-bis(acetoacetoxy)hexane 21
To a 15 mL round-bottomed flask equipped with a magnetic stir
bar was dissolved 1,3-bis(60-acetoacetoxyhexyl)imidazolium
bromide 8 (0.50 g, 0.97 mmol) in chloroform (5 mL). To this stirred
solution was added a solution of silver nitrate (0.17 g, 1.00 mmol) in
deionized water (2 mL). A precipitate formed immediately. The
mixture was allowed to stir overnight at room temperature. The
solids were then filtered and the solvent was removed under
reduced pressure to afford 0.47 g (94%) of the nitrate 10 as a light
1,6-Hexanediol (10.0 g, 0.085 mol), tert-butyl acetoacetate
(53.5 g, 0.34 mmol) and toluene (100 mL) were charged to a two-
necked 250 mL flask, equipped with a short-path distillation
head, receiving flask, and magnetic stir bar. The stirred solution was
warmed to 150 ꢁC and held for 4 h while the tert-butanol/toluene
azeotrope distilled. The remaining volatiles were then removed
under vacuum to achieve 23.2 g of a clear, colorless oil (95%). 1H
yellow oil. 1H NMR (DMSO-d6):
d
1.19e1.38 (m, 8 H, CH2), 1.56
NMR (CHCl3): d 1.30e1.38 (m, 4 H, CH2), 1.57e1.63 (m, 4H, CH2),
(m, 4H, CH2), 1.78 (m, 4H, CH2), 2.17 (s, 6H, CH3), 3.58 (s, 4H, CH2
on AcAc group), 4.04 (t, J ¼ 7 Hz, 4H, AcAcOeCH2), 4.16 (t, J ¼ 7 Hz,
4H, NeCH2), 7.80 (s, 2H, AreH4,5), 9.19 (s, 1H, AreH2). 13C NMR
2.22 (s, 6H, CH3 on AcAc group), 3.41 (s, 4H, CH2 on AcAc group),
4.08 (t, J ¼ 7 Hz, 4H, AcAcOeCH2). 13C NMR (CHCl3):
d 25.43, 28.33,
30.20, 50.09, 65.24, 167.21, 200.69. HR MS (ESI, m/z): [M]þ calcu-
(DMSO-d6):
d
24.61, 25.04, 27.80, 29.13, 48.75, 49.58, 64.23, 122.43,
lated for C14H22O6, 286.1416; found, 286.1428.
Scheme 2. Synthesis of 1,3-bis(2-hydroxyethyl)imidazolium bromide 2.