1650
H.-C. Kan et al. / Tetrahedron 63 (2007) 1644–1653
1
3
d 2.60 (p, J¼7.2 Hz, CCH C, 2H), 2.86 (t, J¼7.4 Hz,
7.50 (d, J¼2.0 Hz, C]CH, 1H); C NMR (100 MHz,
2
N]CCH , 2H), 3.97 (t, J¼7.0 Hz, NCH , 2H), 6.90 (s,
CD OD) d 15.0, 23.5, 26.7, 45.1, 49.0, 118.9, 121.1 (q,
3
2
2
1
3
+
C]CH, 1H), 7.03 (s, C]CH, 1H); C NMR (100 MHz,
CD OD) d 22.9, 25.2, 44.5, 114.3, 132.9, 154.6.
J ¼318 Hz, CF ) 126.2, 153.7; FAB-HRMS m/z [M] calcd
CF
3
for C H N 137.1079, found 137.1082.
8 13 2
3
4.2.2. 1-Methyl-2,3-trimethyleneimidazolium bis(trifluoro-
methanesulfonyl)imide [m-3C-im][NTf ] ionic liquid
4.2.4. 1-Propyl-2,3-trimethyleneimidazolium bis(trifluoro-
methanesulfonyl)imide [p-3C-im][NTf ] ionic liquid
2
2
(
6a, R¼Me). To an ice-cooled round-bottomed flask con-
(6a, R¼Pr). To a round-bottomed flask containing 6,7-di-
hydro-5H-pyrrolo[1,2-a]imidazole 5a (100 mg, 0.93 mmol)
was added bromopropane (125 mg, 1.0 mmol). The alkylation
taining 6,7-dihydro-5H-pyrrolo[1,2-a]imidazole 5a (100 mg,
0
.93 mmol) was added methyl iodide (145 mg, 1.0 mmol).
ꢀ
ꢀ
The alkylation reaction was carried out at 0 C for 1 h. The
reaction mixture was mixed with water (4 mL) and washed
three times with ethyl acetate (3ꢂ2 mL). The residual ethyl
acetate present in aqueous solution was removed in vacuo.
Lyophilization of the aqueous solution afforded the yellow
solid, 1-methyl-2,3-trimethyleneimidazolium iodide, with
excellent isolated yield (213 mg, 92%).
reaction was allowed to proceed at 80 C for 2 h. After the
reaction, the solution was mixed with water (4 mL) and
washed three times with ethyl acetate (3ꢂ2 mL). The residual
ethyl acetate present and the solvent were removed in vacuo
to finally afford a yellow liquid, 1-propyl-2,3-trimethylene-
imidazolium bromide, with excellent isolated yield (207 mg,
97%).
To a solution of 1-methyl-2,3-trimethyleneimidazolium
iodide (100 mg, 0.4 mmol) in water (1 mL) was added
the bistrifluoromethanesulfonimide lithium salt (114 mg,
To a solution of 1-propyl-2,3-trimethyleneimidazolium
bromide (100 mg, 0.43 mmol) in water (1 mL) was added
the bistrifluoromethanesulfonimide lithium salt (125 mg,
0.44 mmol). The mixture was allowed to proceed the ion ex-
change for 12 h at room temperature. The resulting solution
was diluted with dichloromethane (6 mL) and then washed
three times with water (3ꢂ2 mL). Removal of the solvent
under reduced pressure afforded the 1-propyl-2,3-trimethyl-
eneimidazolium bis(trifluoromethylsulfonyl)imide [p-3C-
0
.4 mmol). The mixture was allowed to proceed the ion ex-
change for 12 h at room temperature. The resulting solution
was diluted with dichloromethane (6 mL) and then washed
three times with water (3ꢂ2 mL). Removal of the solvent
under reduced pressure afforded the 1-methyl-2,3-trimethyl-
eneimidazolium bis(trifluoromethylsulfonyl)imide [m-3C-
im][NTf ] (6a, R¼Me) as a white solid (140 mg, 87%); mp
im][NTf ] (6a, R¼Pr) as a yellow liquid (163 mg, 88%);
2
2
ꢀ
1
1
8
3–85 C; H NMR (200 MHz, CD OD) d 2.79 (p, J¼
H NMR (200 MHz, CD OD) d 0.97 (t, J¼7.4 Hz, CH ,
3
3
3
7
.4 Hz, CH , 2H), 3.17 (t, J¼7.5 Hz, N]CCH , 2H), 3.79
3H), 1.78–1.98 (m, CH , 2H), 2.80 (p, J¼8.2 Hz, CH , 2H),
2
2
2
2
(s, NCH , 3H), 4.26 (t, J¼7.3 Hz, NCH , 2H), 7.42 (s,
HC]CH, 2H); C NMR (100 MHz, CD OD) d 23.3, 26.8,
3.19 (t, J¼7.6 Hz, N]CCH , 2H), 4.06 (t, J¼7.3 Hz,
3
2
2
1
3
C]NCH , 2H), 4.27 (t, J¼7.3 Hz, NCH , 2H), 7.45 (d,
3
2
2
3
5.4, 49.3, 118.7, 121.1 (q, J ¼318 Hz, CF ) 127.9,
J¼2 Hz, C]CH, 1H), 7.50 (d, J¼1.8 Hz, C]CH, 1H);
CF
3
+
13
1
found 123.0919.
54.5; FAB-HRMS m/z [M] calcd for C H N 123.0922,
7
C NMR (100 MHz, CD OD) d 10.9, 23.5, 23.9, 26.7,
3
11
2
49.1, 51.4, 118.9, 121.1 (q, J ¼318 Hz, CF ) 126.8, 153.8;
CF
3
+
FAB-HRMS m/z [M] calcd for C H N 151.1235, found
9
15 2
4
.2.3. 1-Ethyl-2,3-trimethyleneimidazolium bis(trifluoro-
methanesulfonyl)imide [e-3C-im][NTf ] ionic liquid (6a,
151.1235.
2
R¼Et). To a round-bottomed flask containing 6,7-dihydro-
4.2.5. 1-Butyl-2,3-trimethyleneimidazolium bis(trifluoro-
methanesulfonyl)imide [b-3C-im][NTf ] ionic liquid
5H-pyrrolo[1,2-a]imidazole 5a (100 mg, 0.93 mmol) was
added bromoethane (111 mg, 1.0 mmol). The alkylation
2
(6a, R¼Bu). To a round-bottomed flask containing 6,7-di-
hydro-5H-pyrrolo[1,2-a]imidazole 5a (100 mg, 0.93 mmol)
was added bromobutane (140 mg, 1.0 mmol). The alkylation
ꢀ
reaction was allowed to proceed at 60 C for 2 h. After the
reaction, the solution was mixed with water (4 mL) and
washed three times with ethyl acetate (3ꢂ2 mL). The
residual ethyl acetate present and the solvent were removed
in vacuo to finally afford a yellow liquid, 1-ethyl-2,3-tri-
methyleneimidazolium bromide, with excellent isolated
yield (219 mg, 97%).
ꢀ
reaction was allowed to proceed at 80 C for 2 h. After the
reaction, the solution was mixed with water (4 mL) and
washed three times with ethyl acetate (3ꢂ2 mL). The resi-
dual ethyl acetate present and the solvent were removed
in vacuo to finally afford a yellow liquid, 1-butyl-2,3-tri-
methyleneimidazolium bromide, with excellent isolated
yield (219 mg, 97%).
To a solution of 1-ethyl-2,3-trimethyleneimidazolium
bromide (100 mg, 0.46 mmol) in water (1 mL) was added
the bistrifluoromethanesulfonimide lithium salt (132 mg,
To a solution of 1-butyl-2,3-trimethyleneimidazolium
bromide (100 mg, 0.41 mmol) in water (1 mL) was added
the bistrifluoromethanesulfonimide lithium salt (118 mg,
0.41 mmol). The mixture was allowed to proceed the ion ex-
change for 12 h at room temperature. The resulting solution
was diluted with dichloromethane (6 mL) and then washed
three times with water (3ꢂ2 mL). Removal of the solvent
under reduced pressure afforded the 1-butyl-2,3-trimethyl-
eneimidazolium bis(trifluoromethylsulfonyl)imide [b-3C-
0
.46 mmol). The mixture was allowed to proceed the ion
exchange for 12 h at room temperature. The resulting solu-
tion was diluted with dichloromethane (6 mL) and then
washed three times with water (3ꢂ2 mL). Removal of the
solvent under reduced pressure afforded the 1-ethyl-2,3-
trimethyleneimidazolium bis(trifluoromethylsulfonyl)imide
[
8
e-3C-im][NTf ] (6a, R¼Et) as a yellow liquid (165 mg,
2
1
6%); H NMR (200 MHz, CD OD) d 1.48 (t, J¼7.4 Hz,
3
CH , 3H), 2.79 (p, J¼8.2 Hz, CH , 2H), 3.20 (t, J¼7.6 Hz,
im][NTf ] (6a, R¼Bu) as a yellow liquid (158 mg, 87%);
3
2
2
1
N]CCH , 2H), 4.13 (q, J¼7.4 Hz, C]NCH , 2H), 4.26
H NMR (200 MHz, CD OD) d 0.98 (t, J¼7.2 Hz, CH ,
2
2
3
3
(
t, J¼7.4 Hz, NCH , 2H), 7.44 (d, J¼2.0 Hz, C]CH, 1H),
3H), 1.28–1.48 (m, CH , 2H), 1.83 (p, J¼7.6 Hz, CH ,
2
2
2