402
C. Matera et al. / European Journal of Medicinal Chemistry 108 (2016) 392e405
After stirring at room temperature for 30 min, the solvent was
removed in vacuo to provide the corresponding salt, which was
crystallized from 2-propanol (135 mg, 80%).
131.2, 134.1, 137.5, 183.1. MS (ESI) m/z [MþH]þ Calcd for C11H13BrNþ:
238.02. Found: 238.1. Anal. Calcd for C11H13BrClN (274.59): C, 48.12;
H, 4.77; N, 5.10. Found: C, 47.85; H, 5.12; N, 4.84.
5 ꢂ HCl: Light brown solid, mp 192e193 ꢁC. 1H NMR (CD3OD):
d
1.99e2.03 (m, 4H), 3.26e3.29 (m, 2H), 3.82 (m, 2H), 7.18 (dd,
7.1.4.8. 6-(3-Iodophenyl)-2,3,4,5-tetrahydropyridine hydrochloride
J ¼ 8.0, 2.2 Hz, 1H), 7.26 (t, J ¼ 2.2 Hz, 1H), 7.33 (dd, J ¼ 8.0, 1.1 Hz,
(12 ꢂ HCl). Crystallized from 2-propanol as a colorless solid (yield
1H), 7.45 (dt, J ¼ 8.0, 1.1 Hz, 1H). 13C NMR (CD3OD):
d
17.0, 17.1, 19.2,
83%), mp 202e204 ꢁC dec. 1H NMR (CD3OD):
d 2.00e2.04 (m, 4H),
45.2, 114.2, 118.6, 121.9, 130.6, 133.1, 158.6, 183.8. MS (ESI) m/z [M]þ
3.27e3.32 (m, 2H), 3.85 (m, 2H), 7.41 (t, J ¼ 7.9 Hz, 1H), 7.88e7.91
Calcd for C11H14NOþ: 176.11. Found: 176.4. Anal. Calcd for
(m,1H), 8.10e8.14 (m,1H), 8.25 (t, J ¼ 1.8 Hz,1H). 13C NMR (CD3OD):
C
11H14ClNO (211.69): C, 62.41; H, 6.67; N, 6.62. Found: C, 62.31; H,
d 16.9,17.0,19.0, 45.4, 94.3,127.3,131.0,133.9,136.5,143.5,183.0. MS
6.89; N, 6.38.
(ESI) m/z [M]þ Calcd for C11H13INþ: 286.01. Found: 286.0. Anal.
Calcd for C11H13ClIN (321.59): C, 41.08; H, 4.07; N, 4.36. Found: C,
40.99; H, 4.32; N, 4.28.
7.1.4.2. (3-(3,4,5,6-Tetrahydropyridin-2-yl)phenyl)methanol hydro-
chloride (6 ꢂ HCl). Crystallized from 2-propanol as light yellow
prisms (yield 65%), mp 141e142 ꢁC. 1H NMR (CD3OD):
d
2.03e2.04
7.1.4.9. 6-(3,5-Dibromophenyl)-2,3,4,5-tetrahydropyridine
chloride (13 ꢂ HCl). Crystallized from diethyl ether as a colorless
solid (yield 44%), mp 95e97 ꢁC. 1H NMR (CD3OD):
2.00e2.03 (m,
hydro-
(m, 4H), 3.30e3.32 (m, 2H), 3.84 (m, 2H), 4.72 (s, 2H), 7.62 (t,
J ¼ 7.7 Hz, 1H), 7.75e7.80 (m, 2H), 7.87 (m, 1H). 13C NMR:
d
17.0, 17.1,
d
19.1, 45.3, 62.9, 125.8, 126.5, 129.5, 132.0, 133.2, 143.9, 184.0. MS
(ESI) m/z [MþH]þ Calcd for C12H16NOþ: 190.12. Found: 190.2. Anal.
Calcd for C12H16ClNO (225.71): C, 63.85; H, 7.14; N, 6.21. Found: C,
63.75; H, 7.41; N, 6.03.
4H), 3.26 (m, 2H), 3.86 (m, 2H), 8.07 (d, J ¼ 1.5 Hz, 2H), 8.17 (t,
J ¼ 1.5 Hz, 1H). 13C NMR (CD3OD):
d 16.8 (2C), 18.9, 45.6, 123.8 (2C),
129.8 (2C), 135.5, 139.4, 182.3. MS (ESI) m/z [M]þ Calcd for
C
11H12Br2Nþ: 315.93. Found: 316.0. Anal. Calcd for C11H12Br2ClN
(353.48): C, 37.38; H, 3.42; N, 3.96. Found: C, 37.21; H, 3.72; N, 3.88.
7.1.4.3. 6-m-Tolyl-2,3,4,5-tetrahydropyridine
hydrochloride
(7 ꢂ HCl). Hygroscopic light brown solid, yield 88%. 1H NMR
7.1.4.10. 6-(3-Bromo-5-fluorophenyl)-2,3,4,5-tetrahydropyridine hy-
drochloride (14 ꢂ HCl). Crystallized from 2-propanol/diethyl ether
(7:3) as a dark yellow solid (yield 51%), mp 65 ꢁC dec. 1H NMR
(CD3OD):
d 2.01e2.05 (m, 4H), 2.47 (s, 3H), 3.30e3.34 (m, 2H),
3.83e3.87 (m, 2H), 7.50e7.55 (m, 1H), 7.59e7.62 (m, 1H), 7.70e7.75
(m, 2H). 13C NMR (CD3OD):
d
17.2, 17.3, 19.2, 20.2, 45.3, 125.1, 128.3,
(CD3OD): d 2.03 (m, 4H), 3.27 (m, 2H), 3.86 (m, 2H), 7.70 (d,
129.4, 132.0, 135.7, 139.9, 183.9. MS (ESI) m/z [MþH]þ Calcd for
J ¼ 8.0 Hz, 1H), 7.82 (d, J ¼ 8.0 Hz, 1H), 7.92 (s, 1H). 13C NMR
C
12H16Nþ: 174.13. Found: 174.2. Anal. Calcd for C12H16ClN (209.72):
(CD3OD):
d
16.9 (2C), 18.9, 45.7, 114.4 (d, J ¼ 24.5 Hz), 123.8 (d,
C, 68.73; H, 7.69; N, 6.68. Found: C, 68.41; H, 8.02; N, 6.40.
J ¼ 9.7 Hz), 124.7 (d, J ¼ 24.5 Hz), 127.1 (d, J ¼ 3.1 Hz), 135.4 (d,
J ¼ 8.6 Hz), 162.8 (d, J ¼ 251.1 Hz), 182.7. MS (ESI) m/z [M]þ Calcd for
7.1.4.4. 6-Phenyl-2,3,4,5-tetrahydropyridine hydrochloride (8 ꢂ HCl).
C
11H12BrFNþ: 256.01. Found: 256.0. Anal. Calcd for C11H12BrClFN
Crystallized from ethanol/diethyl ether (4:1) as a beige solid (yield
(292.58): C, 45.16; H, 4.13; N, 4.79. Found: C, 44.91; H, 4.39; N, 4.52.
91%), mp 88e90 ꢁC. 1H NMR (CD3OD):
d
2.03 (m, 4H), 3.31 (m, 2H),
3.85 (m, 2H), 7.61e7.66 (m, 2H), 7.74e7.79 (m, 1H), 7.89e7.92 (m,
7.1.4.11. (3-Fluoro-5-(3,4,5,6-tetrahydropyridin-2-yl)phenyl)meth-
2H). 13C NMR (CD3OD):
d
17.2, 17.3, 19.3, 45.5, 128.0 (2C), 129.6 (2C),
anol hydrochloride (15 ꢂ HCl). Hygroscopic dark yellow solid, yield
132.0, 135.0,183.8. MS (ESI) m/z [MþH]þ Calcd for C11H14Nþ: 160.11.
Found: 160.2. Anal. Calcd for C11H14ClN (195.69): C, 67.51; H, 7.21;
N, 7.16. Found: C, 67.41; H, 7.43; N, 7.01.
75%. 1H NMR (CD3OD):
d 2.01e2.05 (m, 4H), 3.30e3.32 (m, 2H),
3.84e3.86 (m, 2H), 4.72 (s, 2H), 7.52e7.58 (m, 2H), 7.69 (m, 1H). 13
NMR:
J ¼ 2.9 Hz), 132.7 (d, J ¼ 7.4 Hz), 133.2 (d, J ¼ 24.2 Hz), 143.8 (d,
J ¼ 7.1 Hz), 163.0 (d, J ¼ 247.9 Hz), 183.8. MS (ESI) m/z [MþH]þ Calcd
for C12H15FNOþ: 208.11. Found: 208.2. Anal. Calcd for C12H15ClFNO
(243.71): C, 59.14; H, 6.20; N, 5.75. Found: C, 58.79; H, 6.54; N, 5.43.
C
d
17.1 (2C), 19.1, 45.3, 62.8, 115.3 (d, J ¼ 18.3 Hz), 125.2 (d,
7.1.4.5. 6-(3-Fluorophenyl)-2,3,4,5-tetrahydropyridine hydrochloride
(9 ꢂ HCl). Crystallized from 2-propanol as a light brown solid
(yield 86%), mp 155 ꢁC dec. 1H NMR (CD3OD):
d 2.04 (m, 4H), 3.31
(m, 2H), 3.87 (m, 2H), 7.52e7.57 (m, 1H), 7.68e7.76 (m, 3H). 13C
NMR (CD3OD):
d
17.0 (2C), 19.1, 45.7, 115.0 (d, J ¼ 24.5 Hz), 121.6 (d,
7.2. Pharmacology
J ¼ 21.4 Hz), 124.2 (d, J ¼ 2.9 Hz), 131.8 (d, J ¼ 8.0 Hz), 134.0 (d,
J ¼ 7.7 Hz), 163.0 (d, J ¼ 246.5 Hz), 183.1. MS (ESI) m/z [MþH]þ Calcd
for C11H13FNþ: 178.10. Found: 178.3. Anal. Calcd for C11H13ClFN
(213.68): C, 61.83; H, 6.13; N, 6.56. Found: C, 61.64; H, 6.27; N, 6.31.
7.2.1. Receptor binding assays
Details of the binding experiments to the nicotinic receptor
subtypes have been recently reported for the
a4b2 and a7 subtypes
[57] as well as for the 4 subtype [58]. The Ki values of the novel
a3b
7.1.4.6. 6-(3-Chlorophenyl)-2,3,4,5-tetrahydropyridine hydrochloride
compounds 5-15 were determined by pre-incubating cortex or
hippocampus homogenates with increasing doses (10 pMe10 mM)
of the reference nicotinic agonists, epibatidine or nicotine, and the
drug to be tested for 30 min at room temperature, followed by
overnight incubation with a final concentration of 0.100 nM [3H]-
(10 ꢂ HCl). Crystallized from 2-propanol as a beige solid (yield
85%), mp 144 ꢁC dec. 1H NMR (CD3OD):
d 2.01e2.05 (m, 4H),
3.29e3.32 (m, 2H), 3.86 (m, 2H), 7.62e7.67 (m, 1H), 7.78e7.85 (m,
2H), 7.95e7.97 (m, 1H). 13C NMR (CD3OD):
d 17.2 (2C), 19.0, 45.5,
126.6, 127.9, 131.1, 133.9, 134.5, 135.4, 183.0. MS (ESI) m/z [M]þ Calcd
for C11H13ClNþ: 194.07. Found: 194.1. Anal. Calcd for (230.13): C,
57.41; H, 5.69; N, 6.09. Found: C, 57.16; H, 5.97; N, 5.88.
epibatidine (cortex) or 1 nM [125I]-
a-bungarotoxin (hippocampus),
at the same temperatures as those used for the saturation
experiments.
In the case of HEK 293 transfected a3b4 receptors, the inhibition
7.1.4.7. 6-(3-Bromophenyl)-2,3,4,5-tetrahydropyridine hydrochloride
(11 ꢂ HCl). Crystallized from 2-propanol/diethyl ether (7:3) as a
dark yellow solid (yield 78%), mp 161e164 ꢁC. 1H NMR (CD3OD):
of [3H]epibatidine binding by the studied derivatives was measured
by incubating increasing concentrations of the compounds for
5 min followed by overnight incubation with 0.25 nM [3H]epi-
batidine. For each subtype, the experimental data were analyzed
using the LIGAND program as described by Munson and Rodbard
[59]. The binding parameters were calculated by simultaneously
d
1.99e2.04 (m, 4H), 3.29e3.32 (m, 2H), 3.84 (m, 2H), 7.57 (t,
J ¼ 7.9 Hz, 1H), 7.83e7.86 (m, 1H), 7.93e7.97 (m, 1H), 8.07e8.08 (m,
1H). 13C NMR (CD3OD):
16.9 (2C), 19.0, 45.5, 123.2, 126.8, 130.7,
d