PAPER
Substituted Guanidines and Guanidinium Salts as Potential Ionic Liquids
919
oil 5 was extracted with Et2O (3 × 25 mL) in order to remove impu-
rities, and was finally concentrated under high vacuum.
1H NMR (CDCl3): d = 0.73 (t, J = 5.4 Hz, 6 H), 0.78 (d, J = 6.6 Hz,
3 H), 0.83 (d, J = 6.6 Hz, 3 H), 0.93 (t, J = 6.9 Hz, 6 H), 1.29–1.44
(m, 4 H), 1.96–2.04 (m, 1 H), 2.73–3.29 (m, 8 H), 3.58 (s, 3 H), 3.71
(d, J1 = 5.7 Hz, 1 H).
13C NMR (CDCl3): d = 11.3, 12.9, 18.5, 20.8, 33.6, 38.7, 42.5, 48.7,
51.5, 68.0, 161.2, 175.34.
Methyl (S)-2-{[Bis(dimethylamino)methylene]amino}pro-
panoate (4a)
Colorless oil; [a]20 –73 (c 1.0, CH2Cl2).
1H NMR (CDCl3): d = 1.28 (d, J = 6.7 Hz, 3 H), 2.63 (s, 6 H), 2.65
(s, 6 H), 3.59 (s, 3 H), 4.02 (q, J = 6.7 Hz, 1 H).
13C NMR (CDCl3): d = 21.2, 38.4, 39.6, 51.6, 56.5, 161.4, 176.5.
HRMS (ESI): m/z [M + H]+ calcd for C9H20N3O2: 202.1550; found:
HRMS (ESI): m/z calcd [M + H]+ for C17H36N3O2: 314.2802; found:
314.2798.
(S)-N-[Bis(dimethylamino)methylene]-1-methoxy-N-methyl-1-
oxopropan-2-aminium Iodide (5a)
202.1548.
Colorless oil; [a]20 –39.8 (c 1.24, H2O).
Methyl (S)-2-{[Bis(dimethylamino)methylene]amino}-3-meth-
ylbutanoate (4b)
1H NMR (D2O): d = 1.44 (d, J = 6.7 Hz, 3 H), 2.57 (s, 6 H), 2.63 (s,
6 H), 3.44 (s, 3 H), 4.09 (s, 3 H), 5.13 (q, J = 6.7 Hz, 1 H).
Colorless oil; [a] 20 –211.1 (c 1.22, CH2Cl2).
13C NMR (D2O): d = 14.3, 31.1, 41.6, 53.3, 57.6, 163.8, 171.6.
1H NMR (CDCl3): d = 0.84 (d, J = 4.6 Hz, 3 H), 0.86 (d, J = 4.6 Hz,
3 H), 1.97–2.04 (m, 1 H), 2.63 (s, 6 H), 2.70 (s, 6 H), 3.64 (s, 3 H),
3.70 (d, J = 5.9 Hz, 1 H).
HRMS (ESI): m/z calcd for C10H22N3O2: 216.1707; found:
216.1703.
13C NMR (CDCl3): d = 18.4, 19.5, 33.4, 38.4, 39.6, 51.3, 68.0,
(S)-N-[Bis(dimethylamino)methylene]-1-methoxy-N,3-dimeth-
yl-1-oxobutan-2-aminium Iodide (5b)
161.6, 175.5.
Colorless oil; [a]20 –102.5 (c 1.2, D2O).
HRMS (ESI): m/z [M + H]+ calcd for C11H24N3O2: 230.1863; found:
230.1862.
1H NMR (D2O): d = 1.04 (d, J = 7.02 Hz, 3 H), 1.09 (d, J = 7.06 Hz,
3 H), 1.79–1.94 (m, 1 H), 2.43 (s, 6 H), 2.48 (s, 6 H), 3.48 (s, 3 H),
3.98 (s, 3 H), 4.43 (d, J = 6.4 Hz, 1 H).
13C NMR (D2O): d = 12.5, 16.2, 33.2, 39.0, 40.8, 53.3, 66.1, 161.6,
175.9.
Methyl (S)-2-{[Bis(dimethylamino)methylene]amino}-4-meth-
ylpentanoate (4c)
Colorless oil; [a]20 –15.2 (c 1.0, MeOH).
1H NMR (CDCl3): d = 0.81 (d, J = 6.6 Hz, 3 H), 0.83 (d, J = 7.5 Hz,
3 H), 1.08–1.18 (m, 1 H), 1.41–1.49 (m, 1 H), 1.74–1.83 (m, 1 H),
2.64 (s, 6 H), 2.70 (s, 6 H), 3.64 (s, 3 H), 3.77 (d, J = 6.0 Hz, 1 H).
HRMS (ESI): m/z calcd for C12H26N3O2: 244.2020; found:
244.2015.
13C NMR (CDCl3): d = 11.4, 15.8, 25.2, 38.4, 39.6, 40.1, 51.3, 66.9,
(S)-N-[(Diethylamino)(dipropylamino)methylene]-1-methoxy-
N-methyl-1-oxopropan-2-aminium Iodide (5c)
Reddish brown oil; [a]20 –132.4 (c 1.0, H2O).
1H NMR (D2O): d = 0.79 (t, J = 6.6 Hz, 6 H), 0.91 (t, J = 6.4 Hz, 6
H), 1.12 (d, J = 6.8 Hz, 3 H), 1.68–1.76 (m, 4 H), 1.84–2.40 (m, 8
H), 3.34 (s, 3 H), 3.68 (s, 3 H), 4.18 (q, J = 6.8 Hz, 1 H).
161.6, 175.5.
HRMS (ESI): m/z [M + H]+ calcd for C12H26N3O2: 244.2020; found:
244.2018.
Methyl (S)-2-{[Bis(dimethylamino)methylene]amino}-3-phe-
nylpropanoate (4d)
13C NMR (D2O): d = 11.6, 12.9, 17.5, 20.1, 39.8, 49.3, 53.2, 65.3,
162.2, 172.6.
Colorless oil; [a]20 –220.3 (c 1.20, CH2Cl2).
1H NMR (CDCl3): d = 2.49 (s, 6 H), 2.61 (s, 6 H), 2.84–2.90 (m, 1
H), 3.13–3.17 (m, 1 H), 3.66 (s, 3 H), 4.25 (dd, J1 = J2 = 5.1 Hz, 1
H), 7.13–7.25 (m, 5 H).
HRMS (ESI): m/z calcd for C16H34N3O2: 300.2646; found:
300.2644.
13C NMR (CDCl3): d = 38.3, 38.6, 39.5, 41.9, 51.7, 63.8, 126.0,
(S)-N-[(Diethylamino)(dipropylamino)methylene]-1-methoxy-
N,3-dimethyl-1-oxobutan-2-aminium Iodide (5d)
Brown oil; [a]20 –57.1 (c 1.0, H2O).
1H NMR (D2O): d = 0.83 (t, J = 7.5 Hz, 6 H), 0.91 (d, J = 6.3 Hz, 6
H), 1.12 (t, J = 6.9 Hz, 6 H), 1.48–1.53 (m, 4 H), 1.82–1.95 (m, 1
H), 2.41–2.56 (m, 8 H), 3.73 (s, 3 H), 3.85 (s, 3 H), 4.23 (q, J = 7.2
Hz, 1 H).
129.3, 139.3, 161.7, 175.2.
HRMS (ESI): m/z [M + H]+ calcd for C15H24N3O2: 278.1863; found:
278.1862.
Methyl (S)-2-{[(Diethylamino)(dipropylamino)methylene]ami-
no}propanoate (4e)
Colorless oil; [a]20 –45.1 (c 1.25, CH2Cl2).
13C NMR (D2O): d = 11.3, 13.1, 15.6, 20.6, 27.5, 40.0, 52.8, 65.3,
164.9, 170.2.
1H NMR (CDCl3): d = 0.80 (t, J = 7.5 Hz, 6 H), 0.99 (t, J = 7.2 Hz,
6 H), 1.31 (d, J = 6.9 Hz, 3 H), 1.40–1.48 (m, 4 H), 2.96–3.14 (m, 8
H), 3.62 (s, 3 H), 4.04 (q, J = 6.9 Hz, 1 H).
13C NMR (CDCl3): d = 11.5, 13.4, 20.9, 21.6, 42.5, 49.8, 57.2,
160.8, 175.0.
HRMS (ESI): m/z [M + H]+ calcd for C15H32N3O2: 286.2489; found:
286.2488.
HRMS (ESI): m/z calcd for C18H38N3O2: 328.2959; found:
328.2957.
Methyl (S)-2-[(1,3-Dimethylimidazolidin-2-ylidene)amino]pro-
panoate (8a)
Reddish brown oil; [a]20 –62.4 (c 1.26, CH2Cl2).
1H NMR (CDCl3): d = 1.30 (d, J = 6.9 Hz, 3 H), 2.69 (s, 6 H), 3.19
(s, 4 H), 3.61 (s, 3 H), 4.40 (q, J = 6.9 Hz, 1 H).
13C NMR (CDCl3): d = 22.1, 31.4, 45.0, 51.7, 54.4, 162.0, 176.2.
HRMS (ESI): m/z [M + H]+ calcd for C9H18N3O2: 200.1394; found:
Methyl (S)-2-{[(Diethylamino)(dipropylamino)methylene]ami-
no}-3-methylbutanoate (4f)
Colorless oil; [a]20 –221.4 (c 1.26, CH2Cl2).
200.1391.
Synthesis 2008, No. 6, 917–920 © Thieme Stuttgart · New York