Efficient and recyclable catalysts
Michael addition; typical procedure
A mixture of morpholine (5 mmol), acrylamide (5 mmol), and [ADPQ][CH COO]
3
(
(
10 mol%) was stirred at room temperature. On completion of the reaction
monitored by TLC, mobile phase 2:1 ethyl acetate–methanol), the reaction mixture
was extracted with ethyl acetate. The combined organic phases were evaporated
under reduced pressure. The crude mixture was purified by silica gel column
chromatography (mobile phase 2:1 ethyl acetate–methanol) to afford the desired
1
13
product. The resulting products were characterized by H NMR, C NMR, and
elemental analysis. The residual ionic liquid was dried under vacuum and reused for
subsequent reactions without further processing.
1
3
-(4-Ethylpiperazin-1-yl)-N-(hydroxymethyl)propanamide (entry 13, Table 2)
H
NMR (400 MHz, CDCl ): d 8.83(s, 1H), 4.68(d, 2H, J = 6.4 Hz), 4.58(s, 1H),
3
3
3
5
1
.58–3.69(m, 1H), 3.63(d, 3H, J = 6.4 Hz), 2.53(s, 5H), 2.37–2.43(m, 4H), 1.06(t,
1
3
H, J = 7.2 Hz); C NMR (100 MHz, CDCl ): d 173.9, 63.8, 53.5, 52.5, 52.4,
3
2.2, 52.1, 52.0, 32.3, 11.6. Anal. Calcd for C H N O : C, 55.79; H, 9.83; N,
9.52; O, 14.86. Found: C, 55.74; H, 9.88; N, 19.49; O, 14.89.
1
0 21 3 2
1
N-isopropyl-3-(pyrrolidin-1-yl)propanamide (entry 15, Table 2) H NMR (400 MHz,
CDCl ): d 8.10(s, 1H), 3.95–4.04(m, 1H), 2.76(t, 2H, J = 6.4 Hz), 2.59(s, 4H), 2.37(t,
3
1
H, J = 6.4 Hz), 1.78–1.81(m, 4H), 1.10(d, 6H, J = 6H); C NMR (100 MHz,
3
2
CDCl ): d 171.4, 63.2, 51.6, 40.7, 34.2, 23.5, 22.7. Anal. Calcd for C H N O: C,
3
10 20 2
6
5.18; H, 10.94; N, 15.20; O, 8.68. Found: C, 65.12; H, 10.99; N, 15.17; O, 8.72.
1
N,N-dimethyl-3-(4-methylpiperidin-1-yl)propanamide (entry 16, Table 2)
H
NMR (400 MHz, CDCl ): d 3.72(t, 1H, J = 4.4 Hz), 3.59(t, 1H, J = 4.4 Hz),
3
3
.05(t, 2H, J = 6.0 Hz), 3.00(s, 4H), 2.92(s, 3H), 2.85–2.89(m, 2H), 2.66(t, 2H,
J = 7.6 Hz), 2.17–2.23(m, 2H), 1.96(s, 1H), 1.66(d, 2H, J = 7.6 Hz), 0.92(d, 3H,
1
3
J = 6.0 Hz); C NMR (100 MHz, CDCl ): d 171.2, 72.5, 61.6, 53.6, 53.4, 37.2,
3
3
5.4, 32.9, 30.1, 30.0, 21.5. Anal. Calcd for C H N O: C, 66.62; H, 11.18; N,
11 22 2
1
4.13; O, 8.07. Found: C, 66.56; H, 11.24; N, 14.09; O, 8.11.
1
N-tert-butyl-3-(4-methylpiperidin-1-yl)propanamide (entry 17, Table 2) H NMR
(
J = 6.0 Hz), 2.27(t, 2H, J = 6.0 Hz), 2.18(s, 1H), 1.94–2.00(m, 2H), 1.68(d, 2H,
400 MHz, CDCl ): d 8.60(s, 1H), 2.91(d, 2H, J = 11.6 Hz), 2.53(t, 2H,
3
1
J = 12.8 Hz), 1.34(s, 9H), 1.12–1.22(m, 2H), 0.94(d, 3H, J = 6.4 Hz); C NMR
3
(
Calcd for C H N O: C, 68.98; H, 11.58; N, 12.38; O, 7.06. Found: C, 68.93; H,
100 MHz, CDCl ): d 172.0, 54.4, 53.1, 50.3, 34.5, 33.2, 30.7, 28.9, 21.8. Anal.
3
1
3 26 2
1
1.66; N, 12.32; O, 7.09.
N-(hydroxymethyl)-3-(4-(hydroxymethyl)piperazin-1-yl)propanamide (entry 18,
1
Table 2) H NMR (400 MHz, CDCl ): d 8.72(s, 1H), 4.73(d, 2H, J = 6.4 Hz),
3
3
.70–3.76(m, 2H), 3.62–3.68(m, 2H), 3.05(s, 4H), 2.64–2.67(m, 2H), 2.55–2.59(m,
1
3
H), 2.41(t, 2H, J = 6.4 Hz), 1.24(t, 2H, J = 7.2 Hz); C NMR (100 MHz,
6
CDCl ): d 174.2, 72.4, 64.1, 59.3, 58.3, 57.8, 53.5, 52.8, 52.4, 32.2. Anal. Calcd for
3
C H N O : C, 49.76; H, 8.81; N, 19.34; O, 22.09. Found: C, 49.73; H, 8.85; N,
1
9
19 3 3
9.31; O, 22.11.
123