Alkoxycarbonylpiperidines as N-nucleophiles
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CHCl3); 1H NMR (CDCl3): d = 7.35–7.50 (5H, m, Ar–H),
5.52/4.48 (1H, brs, CHCOO), 3.81/3.77 (major/minor, 3H,
s, OCH3), 3.72–3.62/3.58 (major/minor, 1H, m/brs,
NCHaHb), 3.35–3.26/2.92–2.79 (major/minor, 1H, m,
NCHaHb), 2.42–2.32/2.27–2.16 (major/minor, 1H, m,
CH), 1.87–1.13 (5H, m, CH2) ppm; 13C NMR (CDCl3):
d = 171.6, 171.5, 129.6, 128.4, 126.9, 126.3, 58.4/52.3
(minor/major), 45.8/40.0 (major/minor), 27.4/26.7 (minor/
major), 25.5/24.7 (major/minor), 21.2 ppm; IR (KBr):
CHCl3); H NMR (CDCl3): d = 7.95 (2H, d, J = 7.5 Hz,
Ar–H), 7.65 (1H, t, J = 7.5 Hz, Ar–H), 7.52 (2H, t,
J = 7.5 Hz, Ar–H), 4.59–4.55/4.38–4.33 (1H, m, NCH),
4.19 (2H, q, J = 7.1 Hz, OCH2)/(4.15–4.03 (1H, m,
OCHaHb) and 3.88–3.96 (1H, m, OCHaHb)), 3.72–3.65/
3.53–3.46 (1H, m, NCH), 3.38–3.32/3.26–3.20 (1H, m,
NCH), 3.14–3.04 (1H, m, NCH), 2.68–2.60/2.59–2.51 (1H,
m, CH), 2.17–2.11 (1H, m, CH2), 1.91–1.46 (3H, m, CH2),
1.29/1.15 (3H, t, J = 7.1 Hz, CH3) ppm; 13C NMR
(CDCl3): d = 191.5/191.3, 172.7/172.4, 165.6/165.5,
134.8/134.7, 133.1, 129.7/129.6, 129.0/128.9, 60.9/60.8,
47.6/46.3, 42.9/41.6, 41.4/41.0, 27.4/27.2, 24.7/23.9, 14.2/
14.0 ppm; IR (KBr): vꢀ = 1,730 (COO), 1,681 (PhCO),
1,637 (CON) cm-1; MS: m/z (%) = 289 (8, M?), 244 (6),
184 (85), 156 (66), 128 (28), 105 (100), 77 (60), 51 (13).
vꢀ = 1,740 (COO), 1,635 (CON) cm-1
;
MS: m/z
(%) = 247 (4, M?), 188 (55), 154 (43), 142 (4), 105
(100), 77 (39), 51 (9).
Methyl 1-(2-oxo-2-phenylacetyl)-2-piperidinecarboxylate
(2a0, C15H17NO4)
Yield: 110 mg (40 %); pale yellow viscous material (ca.
70/30 mixture of two C(O)N rotamers); Rf = 0.60 (5 %
EtOAc/CHCl3); 1H NMR (CDCl3): d = 8.10 (2H, d,
J = 7.5 Hz, Ar–H), 7.67 (1H, t, J = 7.5 Hz, Ar–H), 7.56
(2H, t, J = 7.5 Hz, Ar–H), 5.45/4.65 (1H, brs, CHCOO),
3.86/3.70 (major/minor, 3H, s, OCH3), 2.39/2.22 (major/
minor, 1H, m, NCHaHb), 3.54/3.24 (major/minor, 1H, m,
NCHaHb), 3.30/3.02 (major/minor, 1H, m, CH), 1.89–1.25
(5H, m, CH2) ppm; 13C NMR (CDCl3): d = 191.7/191.3
(major/minor), 170.9/170.6 (major/minor), 167.5/166.8
(major/minor), 134.8/134.7 (major/minor), 133.2/133.1
(major/minor), 130.0/129.8 (minor/major), 129.1/128.8
(minor/major), 56.6/52.5 (minor/major), 52.6/51.6 (minor/
major), 44.2/39.3 (major/minor), 27.3/26.3 (minor/major),
24.9/24.4 (major/minor), 21.2/21.0 (major/minor) ppm; IR
(KBr): vꢀ = 1,743 (COO), 1,684 (PhCO), 1,647 (CON)
cm-1; MS: m/z (%) = 275 (2, M?), 216 (7), 170 (30), 142
(100), 105 (70), 77 (40), 51 (12).
Ethyl 1-benzoyl-4-piperidinecarboxylate
(2c, C15H19NO3)
Yield: 104 mg (40 %); yellow viscous material; Rf = 0.51
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(5 % EtOAc/CHCl3); H NMR (CDCl3): d = 7.41 (5H,
brs, Ar–H), 4.55 (1H, brs, NCH2), 4.17 (2H, q, J = 7.1 Hz,
OCH2), 3.76 (1H, brs, NCH2), 3.06 (2H, brs, NCH2),
2.63–2.52 (1H, m, CH), 2.10–1.66 (4H, m, CH2), 1.28 (3H,
t, J = 7.1 Hz, CH3) ppm; 13C NMR (CDCl3): d = 174.2,
170.4, 136.1, 129.6, 128.5, 126.8, 60.7, 47.0, 41.5, 41.1,
28.5, 28.1, 14.2 ppm; IR (KBr): vꢀ = 1,722 (COO), 1,635
(CON) cm-1; MS: m/z (%) = 261 (21, M?), 260 (43), 232
(16), 216 (9), 188 (9), 156 (46), 105 (100), 77 (46), 51 (7).
Ethyl 1-(2-oxo-2-phenylacetyl)-4-piperidinecarboxylate
(2c0, C16H19NO4)
Yield: 234 mg (81 %); yellow viscous material; Rf = 0.74
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(5 % EtOAc/CHCl3); H NMR (CDCl3): d = 7.98 (2H, d,
J = 7.5 Hz, Ar–H), 7.69 (1H, t, J = 7.5 Hz, Ar–H), 7.54
(2H, t, J = 7.5 Hz, Ar–H), 4.44 (1H, br d, J = 13.3 Hz,
NCHaHb), 4.15 (2H, q, J = 7.1 Hz, OCH2), 3.60 (1H, d,
J = 13.3 Hz, NCHaHb), 3.13 (2H, m, NCH2), 2.67–2.56
(1H, m, CHCOO), 2.10–1.66 (4H, m, CH2), 1.28 (3H, t,
J = 7.1 Hz, CH3) ppm; 13C NMR (CDCl3): d = 191.6,
173.7, 165.5, 134.8, 133.1, 129.6, 129.1, 60.8, 45.2, 40.7,
40.4, 28.3, 27.6, 14.2 ppm; IR (KBr): vꢀ = 1,728 (COO),
1,680 (PhCO), 1,645 (CON) cm-1; MS: m/z (%) = 289 (7,
M?), 244 (7), 216 (3), 184 (64), 156 (62), 128 (18), 105
(100), 77 (47), 51 (11).
Ethyl 1-benzoyl-3-piperidinecarboxylate
(2b, C15H19NO3)
Yield: 52 mg (20 %); white viscous material (ca. 1/1
mixture of two C(O)N rotamers); Rf = 0.30 (5 % EtOAc/
CHCl3); 1H NMR (CDCl3): d = 7.42 (5H, brs, Ar–H),
4.71/4.43 (1H, brs, NCH), 4.31–3.99 (2H, brs, OCH2),
3.86/3.67 (1H, brs, NCH), 3.28/3.16 (1H, brs, NCH),
3.14–3.02 (1H, m, CH), 2.61/2.45 (1H, brs, NCH),
2.17–2.11 (1H, m, CH2), 1.94–1.42 (3H, m, CH2), 1.28
(3H, brs, CH3) ppm; 13C NMR (CDCl3): d = 173.1, 170.6,
136.0, 129.6, 128.5, 126.9, 60.7, 49.2/48.1, 44.2/42.5, 42.0/
41.3, 25.0/24.0, 27.5, 14.1 ppm; IR (KBr): vꢀ = 1,730
(COO), 1,631 (CON) cm-1; MS: m/z (%) = 261 (20, M?),
260 (32), 216 (8), 188 (41), 156 (47), 105 (100), 77 (47), 51
(8).
Methyl 1-[(androst-16-en-17-yl)carbonyl]-2-
piperidinecarboxylate (3a, C27H41NO3)
Yield: 265 mg (62 %); beige solid material (ca. 3/1 mixture
of two C(O)N rotamers); m.p.: 104–105 °C; Rf = 0.76 (5 %
EtOAc/CHCl3); 1H NMR (CDCl3): d = 5.79/5.73 (1H, brs,
16-CH), 5.46/4.91 (major/minor, 1H, brs, NCH), 4.59/4.03
(minor/major, 1H, brs/m, NCH), 3.74 (3H, s, OCH3), 3.14/
2.69 (major/minor, 1H, m/brs, NCH), 2.25 (2H, m, CH2),
2.08–0.72 (26H, m, skeleton protons ? (CH2)2), 1.05 (3H, s,
Ethyl 1-(2-oxo-2-phenylacetyl)-3-piperidinecarboxylate
(2b0, C16H19NO4)
Yield: 251 mg (87 %); yellow viscous material (ca. 1/1
mixture of two C(O)N rotamers); Rf = 0.71 (5 % EtOAc/
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