quaternary salts are lowest regardless of the chain length of the
substituent and the morpholinium quaternary salts are most
viscous.
N-2-(2-Ethoxyethoxy)ethyl-N-methyltriazolium bromide (4a).
95% yield, yellow viscous liquid; IR (KBr): 3103, 3021, 2952,
2870, 1794, 1625, 1529, 1508, 1427, 1379, 1320, 1165, 953 cm−1;
1H NMR: d 1.15 (t, J = 6.99 Hz, 3H), 3.49 (q, J = 6.99, 2H), 3.58
(m, 2H), 3.71 (m, 2H), 4.00 (t, J = 4.95, 2H), 4.29 (s, 3H), 4.82
(t, J = 4.75, 2H), 9.39 (s, 1H), 11. 16 (s. 1H); 13C NMR: d 145.78,
144.55, 70.83, 70.27, 68.77, 66.76, 48.83, 39.48, 15.57; MS (solid
probe) (EI) m/z (%) 200 (M+, 42).
Experimental
General methods
1H, 19F, and 13C NMR spectra were recorded using a Bruker
spectrometer operating at 300, 282, 75 MHz, respectively, in
acetone-d6 unless otherwise stated. Chemical shifts are reported
in ppm relative to the appropriate standard. IR spectra were
recorded using KBr plates on a BIO-RAD FTS 3000 Infrared
spectrometer. Mass spectra were obtained at 70 eV with a
Shimadzu QP5050A GC/MS spectrometer and for ionic solids,
the solids probe was utilized. Fragmentation is reported only for
the cation in the ionic liquids. Elemental analyses were obtained
from the Shanghai Institute of Organic Chemistry, China.
Products were sometimes purified by silica-gel chromatography.
DSC was measured at a heating rate of 10 °C min−1 over the
range between −78 and 400 °C on a TA Instruments DSC Q10.
Thermogravimetric analysis measurements were made using a
TA Instrument TA 50. Densities and viscosities of the ionic
liquids were measured by using a pycnometer and a viscometer
(Minivis II, Grabner Instruments), respectively. Tetrahydrofuran
and glyme were dried with sodium and distilled over a purple
solution of benzophenone immediately before use. Chemicals
were purchased from Sigma-Aldrich, Acros, Lancaster,
Synquest and Fluka. During the experiments, a Schlenk line
system was used for handling the air- and moisture-sensitive
reactions under nitrogen.
N-Methoxyethyl-N-methyloxazolidinium
bromide
(1b).
93% yield, yellow viscous liquid; IR (KBr): 3472, 2998, 2732,
1
1623, 1521, 1321, 970, 882, 762 cm−1; H NMR (D2O): d 3.10
(s, 3H), 3.20 (s, 3H), 3.58–3.81 (m, 6H), 4.21 (m, 2H), 4.71 (d,
J = 5.97 Hz, 1H), 4.84 (d, J = 5.97 Hz, 1H); 13C NMR (D2O): d
94.02, 66.64, 66.55, 62.05 (t, J = 3.51 Hz), 61.80 (t, J = 2.64 Hz),
59.22, 48.37 (t, J = 3.56 Hz); MS (solid probe) (EI) m/z (%) 146
(M+, 100).
N-Methoxyethyl-N-methylmorpholinium bromide (2b). 90%
yield, white solid; IR (KBr): 3421, 2189, 1694, 1453, 1321, 1286,
1
1109, 1015, 889 cm−1; H NMR (D2O): d 3.22 (s, 3H), 3.34 (s,
3H), 3.52 (m, 4H), 3.68 (m, 2H), 3.88 (br m, 2H), 3.99 (br m,
4H); 13C NMR (D2O): d 66.42, 64.92, 62.04, 60.10, 59.19, 48.90;
MS (solid probe) (EI) m/z (%) 160 (M+, 100).
N-Methoxyethyl-N-methylimidazolium bromide (3b)25. 90%
1
yield, yellow viscous liquid; IR (KBr): cm−1; H NMR (D2O):
d 3.31 (s, 3H), 3.70 (t, J = 4.99 Hz, 2H), 3.82 (s, 3H), 4.32 (t,
J = 5.07 Hz, 2H), 7.38 (s, 1H), 7.43 (s, 1H) 13C NMR: d 137.70,
124.13, 123.28, 71.01, 59.12, 51.01, 37.19; MS (solid probe) (EI)
m/z (%); 161 (M+, 54)
General procedure for the preparation of quaternary salts (1–4a,
1–4b)
N-Methoxyethyl-N-methyltriazolium bromide (4b). 90% yield,
yellow viscous liquid; IR (KBr): 3480, 2948, 2832, 2309, 1629,
1
1424, 1293, 981 cm−1; H NMR (D2O): d 3.39 (s, 3H), 3.84 (t,
In a typical reaction, N-methyloxazolidine (0.87 g, 10 mmol)
and 2-(2-ethoxyethoxy)ethyl bromide (20.69 g, 10.5 mmol) were
placed in a 20 mL Pyrex glass tube which was evacuated, sealed
and then heated for 24 h at 70 °C. All of the volatile materials
were removed at reduced pressure and the residue was subjected
to dynamic vacuum for 1 day leaving the pure quaternary salt.
The product (1a) was obtained in 93% yield. The compounds
which were used in further synthetic reactions were not sub-
jected to elemental analyses.
J = 4.71 Hz, 2H), 4.13 (s, 3H), 4.52 (t, J = 4.87 Hz, 2H), 8.85
(s, 1H); 13C NMR (D2O): d 145.58, 143.24, 70.04, 59.40, 48.79,
39.86; MS (solid probe) (EI) m/z (%) 142 (M+, 60).
General procedure for the preparation of 5a–8a and 5b–8b
Lithium bis(trifluoromethanesulfonyl)amide (10.50 mmol)
was added to magnetically stirred solution of bromide 1a
(10.00 mmol) in water (5 mL). After 3 h at room temperature,
the oily liquid was separated and washed with a small amount
of water (3 × 20 mL) and evaporated in vacuo to give 5a in 97%
yield.
N-2-(2-Ethoxyethoxy)ethyl-N-methyloxazolidinium bromide
(1a). 93% yield, yellow viscous liquid; IR (KBr): 2994, 2915,
1
1483, 1390, 1284, 1198, 1132, 1053, 943, 893, 810 cm−1; H
NMR: d 1.12 (t, J = 7.09, 3H), 3.17 (s, 3H), 3.53 (q, J = 7.08 Hz,
2H), 3.62–3.82 (m, 8H), 3.90 (br s, 2H), 4.31 (m, 2H), 4.93 (d,
J = 5.87 Hz, 1H), 4.81 (d, J = 5.87 Hz, 1H); 13C NMR: d 94.52,
70.96, 69.93, 66.87, 65.69, 64.72, 64.49, 61.31, 48.51 (br), 15.02;
MS (solid probe) (EI) m/z (%) 204 (M+, 34).
N-2-(2-Ethoxyethoxy)ethyl-N-methyloxazolidinium
bis(trifluoromethanesulfonyl)amide (5a). 97% yield, color-
less viscous liquid; IR (KBr): 3421, 2987, 2379, 1377, 1120,
1
1090, 965, 889 cm−1; H NMR: d 1.15 (t, J = 7.00, 3H), 3.44
(s, 3H), 3.51 (q, J = 7.00 Hz, 2H), 3.60 (m, 2H), 3.72 (m, 2H),
3.94–4.16 (m, 6H), 4.47 (m, 2H), 5.08 (d, J = 5.79 Hz), 5.20 (d,
J = 5.79 Hz, 1H); 13C NMR 120.99 (q, JC–F = 320.93), 94.67,
71.16, 70.13, 66.77, 66.69, 65.58 (t, J = 3.51 Hz) 65.28, 62.32 (t,
J = 3.00 Hz), 48.26 (t, J = 3.34 Hz); 19F NMR: d −79.88 (s, 6F);
MS (solid probe) (EI) m/z (%) 204 (M+, 100). Anal. Found: C,
29.60; H, 4.50; N, 5.91. C13H24F6N2O7S2 requires C, 29.75; H,
4.54; N, 5.79%.
N-2-(2-Ethoxyethoxy)ethyl-N-methylmorpholinium bromide
(2a). 90% yield, yellow viscous liquid; IR (KBr) 3104, 2931,
1
2901, 2860, 1739, 1640, 1520, 1304, 1284, 1017, 951 cm−1; H
NMR: d 1.14 (t, J = 7.01 Hz, 3H), 3.49 (q, J = 7.00 Hz, 2H),
3.59 (m, 2H), 3.62 (s, 3H), 3.72 (m, 2H), 3.87 (m, 4H), 4.15 (br s,
8H); 13C NMR: d 71.20, 70.18, 66.78, 65.06, 63.89 (br s), 61.52,
61.28, 49.50 (br s), 15.21; MS (solid probe) (EI) m/z (%) 218
(M+, 100).
N-2-(2-Ethoxyethoxy)ethyl-N-methylmorpholinium
bis(trifluoromethanesulfonyl)amide (6a). 90% yield, yellow
viscous liquid; IR (KBr) 3467, 2082, 1641, 1423, 1411, 1234,
N-2-(2-Ethoxyethoxy)ethyl-N-methylimidazolium
bromide
1
1116, 883 cm−1; H NMR: d 1.14 (t, J = 7.00 Hz, 3H), 3.49 (q,
(3a). 93% yield, yellow viscous liquid; IR (KBr): 3428, 2995,
1
1592, 1520, 1472, 1395, 1260, 996, 921, 883 cm−1; H NMR: d
J = 7.00 Hz, 2H), 3.50 (s, 3H), 3.58 (m, 2H), 3.69 (m, 2H), 3.73
(br t, 2H), 3.80 (br t, 2H), 3.96 (m, 2H), 4.13 (br s, 6H); 13C
NMR: d 120.99 (q, JC–F = 321.16 Hz) 71.04, 70.16, 66.77, 64.87,
1.13 (t, J = 6.99 Hz, 3H), 3.47 (q, J = 7.00 Hz, 3H), 3.55 (m,
2H), 3.67 (m, 2H), 3.95 (br t, J = 5.03, 2H), 4.13 (s, 3H), 4.66
(br t, J = 4.78, 2H), 7.89 (t, J = 1.16, 1H) 7.98 (t, J = 1.64, 1H),
10.05 (s, 1H); 13C NMR: d 132.04, 124.07, 123.93, 70.95, 70.35,
69.56, 66.78, 50.18, 36.20, 15.56; MS (solid probe) (EI) m/z (%)
199 (M+, 45).
64.33 (br s), 61.72, 61.72 (t, J = 2.30 Hz) 61.24, 49.35 (br s); 19
F
NMR: d −79.86 (s, 6F); MS (solid probe) (EI) m/z (%) 218 (M+,
100). Anal. Found: C, 31.09; H, 4.81; N, 5.60. C13H24F6N2O7S2
requires C, 31.13; H, 4.81; N, 5.62%.
2 7 3 2
O r g . B i o m o l . C h e m . , 2 0 0 4 , 2 , 2 7 2 8 – 2 7 3 4