PAPER
Ionic Liquid-Promoted Synthesis of N-Alkyl and N-Arylimides
997
Table 3 The Synthesis of Some Imide Derivatives Under Different
Reaction Conditions
N-(1-Naphthyl)succinimide (1e)
Colorless compound; mp 147.5–149.5 °C (lit. 147–149 °C).
11
IR (KBr): 3053, 2937, 1705, 1600, 1511, 1407, 1375, 1185, 803,
Yields(%)
–
1
7
75, 678 cm .
Product
This
Literature method
1
work
H NMR (CDCl ): d = 7.96 (t, J = 8.5 Hz, 2 H), 7.52–7.59 (m, 4 H),
3
Aa
Bb
Cc
7.35 (d, J = 6.4 Hz, 1 H), 2.95–3.12 (m, 4 H).
N-benzylsuccinimide
N-phenylmaleimide
N-phenylphthalimide
92
97
98
91
97
80
79
92
N-(5-Methyl-1,3,4-thiodiazol-2-yl)succinimide (1f)
Colorless compound; mp 280 °C (decomp.).
IR (KBr): 3187, 3067, 2981, 2924, 1697, 1682, 1555, 1366, 1270,
–
1
1
163, 762 cm .
69
1
H NMR (DMSO-d ): d = 2.97 (q, J = 7.5 Hz, 2 H), 2.68 (t, J = 6.4
6
a
6
Lit. : yields for the reaction catalyzed by ZnBr and HMDS, stirring
at reflux in benzene, and the reaction time is more than 2.5 h.
Hz, 2 H), 2.55 (t, J = 6.4 Hz, 2 H), 1.28 (t, J = 7.6 Hz, 3 H).
b
12
Lit. : yields for the reaction catalyzed by TaCl –silica gel, stirring
N-Benzylsuccinimide (1g)
Colorless needles; mp 99.2–100.5 °C (lit. 98.0–99.0 °C).
5
6
at r.t. for 1 h, and irradiating in a microwave oven for 5–6 min.
c
4a
Lit. : yields for the reaction reflux in p-cymene overnight.
IR (KBr): 3072, 3036, 1694, 1431, 1310, 717, 698 cm–1.
1
H NMR (CDCl ): d = 7.39 (d, J = 7.2 Hz, 2 H), 7.26–7.32 (m, 3 H),
3
4
.65 (s, 2 H), 2.70 (s, 4 H).
Mps were determined on a digital mp apparatus and were not cor-
rected. IR spectra were recorded on a VECTOR22 (Bruker) instru-
ment, and NMR spectra were recorded on an AVANCE DMX 400
N-Butylsuccinimide (1h)
Oily compound (lit. oily compound).
IR (KBr): 2954, 1774, 1697, 1401, 880, 718 cm–1.
1
4
(Bruker) spectrometer. The ionic liquids [bmim][BF4],
[
bmim][PF ] and [Bmim]Cl were synthesized according to reported
6
1
3
1H NMR (CDCl
procedures. The other materials are commercially available and
were used without further purification.
3
): d = 3.50 (t, J = 7.6 Hz, 2 H), 2.70 (s, 4 H), 155
(m, 2 H), 1.30 (m, 2 H), 0.91 (t, J = 7.4 Hz, 3 H).
N-Phenylmaleimide (2a)
N-Alkylation of Heterocyclic Compounds; General Procedure
Anhydride (2 mmol) and corresponding amine (2 mmol) were add-
6
Colorless compound; mp 89.3–90.0 °C (lit. 89.0–90.0 °C).
ed to ionic liquid [Bmim][PF ] (2 mL). The mixture was stirred at
6
IR (KBr): 3106, 3094, 1709, 1597, 1508, 1394, 1146, 832, 756, 697
cm .
1
40 °C for 5–20 min (reaction time see Table 1) and cooled. The
–1
product was extracted with Et O (3 × 10 mL). The combined ethe-
2
1
H NMR (CDCl ): d = 7.47 (t, J = 7.6 Hz, 2 H), 7.33–7.39 (m, 3 H),
real phase was evaporated under reduced pressure to give crude
product. The crude product was purified by recrystallization to give
the corresponding pure N-alkyl or N-arylimide. After filtering off
the product the rest of the viscous ionic liquid was further washed
3
6
.85 (s, 2 H).
N-p-Chlorophenylmaleimide (2b)
Colorless compound; mp 115.3–116.9 °C.
with a mixture of Et O–EtOAc (1:1) and dried at 80 °C under re-
2
–
1
duced pressure for several hours and reused in subsequent runs.
IR (KBr): 3090, 1716, 1497, 1388, 1148, 832, 687, 505 cm .
1
H NMR (CDCl ): d = 7.44 (d, J = 8.7 Hz, 2 H), 7.31 (d, J = 8.7 Hz,
3
N-Phenylsuccinimide (1a)
Colorless needles; mp 155.6–156.7 °C (lit. 156.0–157.0 °C).
2
H), 6.88 (s, 2 H).
6
–
1
IR (KBr): 3055, 2938, 1708, 1505, 1394, 1189, 765, 698 cm .
N-Benzylmaleimide (2c)
6
1
Colorless compound; mp 70.0–71.1 °C (lit. 69.5–70.5 °C).
H NMR (CDCl ): d = 7.48 (m, 2 H), 7.40 (m, 1 H), 7.27 (d, J = 7.6
3
Hz, 2 H), 2.86 (s, 4 H).
IR (KBr): 3091, 3068, 2948, 1698, 1457, 1407, 1354, 1137, 842,
–
1
7
23, 693 cm .
N-p-Chlorophenylsuccinimide (1b)
Colorless needles; mp 163.1–164.0 °C.
1
H NMR (CDCl ): d = 7.26–7.35 (m, 5 H), 6.70 (s, 2 H), 4.67 (s, 2
3
H).
–
1
IR (KBr): 3101, 2978, 2949, 1708, 1493, 1380, 1168, 833 cm .
1
N-(1-Naphthyl)maleimide (2d)
Yellow compound; mp 113.9–114.1 °C (lit. 116–117 °C).
H NMR (CDCl ): d = 7.44 (d, J = 8.7 Hz, 2 H), 7.25 (d, J = 8.7 Hz,
3
5
f
2
H), 7.27 (d, J = 7.6 Hz, 2 H), 2.89 (s, 4 H).
IR (KBr): 3096, 3065, 3016, 1708, 1596, 1509, 1370, 1350, 1136,
842, 801, 773, 694 cm .
–
1
N-p-Methylphenylsuccinimide (1c)
Colorless needles; mp 154.8–155.4 0 °C.
1
H NMR (CDCl ): d = 7.96 (t, J = 8.8 Hz, 2 H), 7.57 (m, 4 H), 7.38
3
–
1
IR (KBr): 3041, 2935, 1708, 1519, 1394, 1187, 829 cm .
(d, J = 6.4 Hz, 1 H), 6.97 (s, 2 H).
1
H NMR (CDCl ): d = 7.28 (d, J = 7.3 Hz, 2 H), 7.14 (d, J = 6.5 Hz,
3
N-Phenylphthalimide (3a)
Colorless compound; mp 207.9–209.3 °C (lit. 208–209 °C).
2
H), 2.86 (s, 4 H), 2.37 (s, 3 H).
4
a
–
1
N-p-Nitrophenylsuccinimide (1d)
IR (KBr): 3063, 1770, 1715, 1515, 1384, 1118, 724, 692 cm .
Colorless needles; mp 209.9–210.9 °C.
1
H NMR (CDCl ): d = 7.95 (dd, J = 5.6, 3.2 Hz, 2 H), 7.80 (dd,
3
–
1
IR (KBr): 3120, 2945, 1713, 1525, 1504, 1349, 1168, 854 cm .
J = 5.6, 3.2 Hz, 2 H), 7.48 (m, 2 H), 7.40 (m, 1 H), 7.27 (d, J = 7.6
1
Hz, 2 H).
H NMR (DMSO-d ): d = 8.37 (d, J = 8.4 Hz, 2 H), 7.61 (d, J = 8.4
6
Hz, 2 H), 2.82 (s, 4 H).
Synthesis 2004, No. 7, 995–998 © Thieme Stuttgart · New York