E. Große Maestrup et al. / Bioorg. Med. Chem. 17 (2009) 3630–3641
3639
[MꢁCH2PhF], 109 [FPhCH2]. IR:
m
(cmꢁ1) = 2913 (C–H), 1641 (C@C),
827 (C–H, 1,4 disubst. aromat.), 757 (C–H, 1,2 disubst. aromat.).
1H NMR (CDCl3): d (ppm) = 1.69–2.10 (m, 4H, N(CH2CH2)2), 3.22–
3.42 (m, 1H, N(CH2CH2)2), 3.50 (s, 3H, OCH3), 3.52–3.65 (m, 1H,
N(CH2CH2)2) 3.69–3.84 (m, 1H, N(CH2CH2)2), 4.63–4.81 (m, 1H,
N(CH2CH2)2), 6.01 (s, 1H, ArCH), 7.11 (t, J = 8.7 Hz, 2H, FC(CHCH)2),
7.13–7.18 (m, 1H, aromat. H), 7.33–7.42 (m, 3H, aromat. H), 7.47
1507 (aromat. C@C), 1219 (C–F), 1090 (C–O), 827 (C–H, 1,4 disubst.
aromat.), 754 (C–H, 1,2 disubst. aromat.). 1H NMR (CDCl3): d
(ppm) = 1.65–1.73 (m, 2H, N(CH2CH2)2,), 1.88 (td, J = 13.1/4.5 Hz,
1H, N(CH2CH2)2), 2.03 (td, J = 13.0/4.5 Hz,1H, N(CH2CH2)2), 2.39–
2.47 (m, 2H, N(CH2CH2)2), 2.49–2.61 (m, 2H, CH2–CH@CH2), 2.77
(d, J = 11.0 Hz, 2H, N(CH2CH2)2), 3.52 (s, 2H, NCH2Ph), 5.04–5.13
(m, 2H, CH2–CH@CH2), 5.24 (t, J = 5.8 Hz, 1H, ArCH), 5.78–5.90
(m, 1H, CH2–CH@CH2), 6.99 (t, J = 8.7 Hz, 2H, FC(CHCH)2), 7.08–
7.16 (m, 2H, aromat. H), 7.21–7.33 (m, 4H, aromat. H). Purity
(HPLC, method 1): 95.8%.
(2d, J = 8.7 Hz, 2H, FC(CHCH)2). 1H NMR (C6H5NO2, rt):
d
(ppm) = 1.64–1.80 (m, 1H, N(CH2CH2)2), 1.80–2.00 (m, 1H,
N(CH2CH2)2), 2.09 (td, J = 13.0/4.5 Hz, 1H, N(CH2CH2)2), 2.20 (td,
J = 13.1/4.8 Hz, 1H, N(CH2CH2)2), 3.33–3.54 (m, 1H, N(CH2CH2)2),
3.51 (s, 3H, OCH3), 3.48–3.75 (m, 1H, N(CH2CH2)2), 3.77–4.08 (m,
1H, N(CH2CH2)2), 4.71–5.08 (m, 1H, N(CH2CH2)2), 6.19 (s, 1H,
ArCH), 7.16 (t, J = 8.8 Hz, 2H, FC(CHCH)2), 7.30 (d, J = 8.3 Hz, 1H,
aromat. H), 7.33–7.45 (m, 3H, aromat. H), 7.64–7.71 (m, 2H,
FC(CHCH)2). The signals of the protons adjacent to the N-atom
are very broad. 1H NMR (C6H5NO2, 100 °C): d (ppm) = 1.71 (d,
J = 13.5 Hz, 1H, N(CH2CH2)2), 1.90 (d, J = 13.5 Hz, 1H, N(CH2CH2)2),
2.07 (td, J = 13.1/4.8 Hz, 1H, N(CH2CH2)2), 2.14 (td, J = 13.3/4.8 Hz,
1H, N(CH2CH2)2), 3.53 (s, 3H, OCH3), 3.53–3.63 (m, 2H,
N(CH2CH2)2), 4.24–4.42 (m, 2H, N(CH2CH2)2), 6.19 (s, 1H, ArCH),
7.13 (t, J = 8.8 Hz, 2H, FC(CHCH)2), 7.24–7.29 (m, 1H, aromat. H),
7.30–7.43 (m, 3H, aromat. H), 7.59–7.67 (m, 2H, FC(CHCH)2). Purity
(HPLC, method 2): 97.7%.
7.10. 10-[4-(N,N-Dimethylamino)benzoyl]-3-methoxy-3H-
spiro[[2]benzofuran-1,40-piperidine] (15)
A mixture of secondary amine 7 (99 mg, 0.45 mmol), p-(dimeth-
ylamino)benzoyl chloride (107 mg, 0.65 mmol) and NEt3 (0.15 mL)
in CH2Cl2 (20 mL) was stirred for 6 h at rt. Then, 2 M NaOH was
added (pH 10) and after 1 h the organic layer was separated. The
aqueous layer was extracted twice with CH2Cl2, the combined or-
ganic layers were dried (Na2SO4), concentrated in vacuo and the
residue was purified by fc (2 cm, cyclohexane:ethyl acetate 7:3,
10 mL, Rf 0.09). Colorless viscous oil, yield 50 mg (31%).
C22H26N2O3 (366.5). MS (EI): m/z = 366 [M], 218 [M–OCPhN(CH3)2),
186 [MꢁOCPhN(CH3)2–OCH3], 148 [OCPhN(CH3)2]. IR:
m
7.12. 3H-Spiro[[2]benzofuran-1,40-piperidine]-3-carbonitrile
(19)
(cmꢁ1) = 2923 (C–H), 1627 (C@O amide), 1523 (aromat. C@C),
1357 (C-N amide), 1083 (C–O), 823 (C–H, 1,4 disubst. aromat.),
757 (C–H, 1,2 disubst. aromat.). 1H NMR (CDCl3): d (ppm) = 1.50–
1.72 (m, 2H, N(CH2CH2)2), 1.76–2.06 (m, 2H, N(CH2CH2)2), 3.02
(s, 6H, N(CH3)2), 3.27–3.56 (m, 2H, N(CH2CH2)2), 3.50 (s, 3H,
OCH3), 6.09 (s, 1H, ArCH), 6.75–6.93 (m, 2H, (CH3)2NC(CHCH)2),
7.13–7.18 (m, 1H, aromat. H), 7.32–7.47 (m, 5H, aromat. H). The
signals of the piperidine ring protons are very broad, signals for
two protons adjacent to the N-atom are not seen. 1H NMR
(C6H5NO2, rt): d (ppm) = 1.75 (dd, J = 13.4/1.9 Hz, 1H, N(CH2CH2)2),
1.91 (d br, J = 11.9 Hz, 1H, N(CH2CH2)2), 2.11 (td, J = 13.0/4.7 Hz,
1H, N(CH2CH2)2), 2.22 (td, J = 13.1/4.8 Hz, 1H, N(CH2CH2)2), 2.89
(s, 6H, N(CH3)2), 3.51–3.65 (m, 2H, N(CH2CH2)2), 3.57 (s, 3H,
OCH3), 4.40–4.67 (m, 2H, N(CH2CH2)2), 6.21 (s, 1H, ArCH), 6.66
(d, J = 8.9 Hz, 2H, (CH3)2NC(CHCH)2), 7.28 (d, J = 8.3 Hz, 1H, aromat.
H), 7.34–7.46 (m, 3H, aromat. H), 7.51 (d, J = 8.9 Hz, 2H,
(CH3)2NC(CHCH)2). The signals of the protons adjacent to the N-
atom are very broad. 1H NMR (C6H5NO2, 100 °C): d (ppm) = 1.73
(ddd, J = 13.4/5.3/2.6 Hz, 1H, N(CH2CH2)2), 1.93 (ddd, J = 13.4/5.3/
2.7 Hz, 1H, N(CH2CH2)2), 2.10 (td, J = 13.1/4.7 Hz, 1H, N(CH2CH2)2),
2.16 (td, J = 13.1/4.7 Hz, 1H, N(CH2CH2)2), 2.93 (s, 6H, N(CH3)2),
3.54–3.62 (m, 2H, N(CH2CH2)2), 3.55 (s, 3H, OCH3), 4.41–4.53 (m,
2H, N(CH2CH2)2), 6.21 (s, 1H, ArCH), 6.72 (d, J = 8.9 Hz, 2H,
(CH3)2NC(CHCH)2), 7.25–7.29 (m, 1H, aromat. H), 7.32–7.43 (m,
3H, aromat. H), 7.57 (d, J = 8.9 Hz, 2H, (CH3)2NC(CHCH)2). Purity
(HPLC, method 2): 92.7%.
Under N2 the carbonitrile 1821 (100 mg, 0.33 mmol) was dis-
solved in CH3OH (20 mL). Pd/C (25 mg, 10% (m/m)) and dried
ammonium formate (104 mg, 1.64 mmol) were added. The mixture
was heated to reflux for 8 h. After periods of 1.5 h and 7 h ammo-
nium formate (12 mg) was added. After cooling to rt the mixture
was filtered with CeliteÒ. The solvent was removed in vacuo and
the residue was purified by fc (3 cm, ethyl acetate:metha-
nol:ammonia 90:10:2, 20 mL, Rf 0.05) several times. Pale yellow
oil, yield 28 mg (44%). C14H16N2O (214.3). MS (EI): m/z = 215 [M],
171 [M–C2H5N], 115 [PhCH2CN]. IR:
m
(cmꢁ1) = 3333 (N-H), 2942
(C–H), 1607 (C@C), 1045 (C–O), 754 (C–H, 1,2 disubst. aromat.).
1H NMR (CDCl3): d (ppm) = 1.70 (ddd, 2H, J = 13.6/4.9/2.4 Hz,
N(CH2CH2)2), 1.87–1.98 (m, 2H, N(CH2CH2)2), 3.03–3.14 (m, 4H,
N(CH2CH2)2), 5.84 (s, 1H, Ar-CH-O), 7.17–7.24 (m, 1H, aromat. H),
7.38–7.44 (m, 3H, aromat. H). 13C NMR (CDCl3): d (ppm) = 36.8
(1C, N(CH2CH2)2), 37.1 (1C, N(CH2CH2)2), 42.3 (1C, N(CH2CH2)2),
42.5 (1C, N(CH2CH2)2), 69.2 (1C, ArCHCN), 88.2 (1C, ArCO), 118.5
(1C, CN), 121.7 (1C, aromat.CH), 122.3 (1C, aromat.CH), 129.2 (1C,
aromat.CH), 130.2 (1C, aromat.CH), 133.8 (1C, aromat.C), 145.3
(1C, aromat.C). Purity (HPLC, method 1): 76.2%.
8. Receptor binding studies
8.1. Materials and general procedures
7.11. 10-(4-Fluorobenzoyl)-3-methoxy-3H-spiro[[2]benzofuran-
1,40-piperidine] (17)
Guinea pig brains and rat livers were commercially available
(Harlan-Winkelmann, Germany). Homogenizer: Elvehjem Potter
(B. Braun Biotech International). Centrifuge: High-speed cooling
centrifuge model Sorvall RC-5C plus (Thermo Finnigan). Filter:
Printed Filtermat Type A (Perkin Elmer), presoaked in 0.5% aqueous
polyethylenimine for 2 h at rt before use. The filtration was carried
out with a MicroBeta FilterMate-96 Harvester (Perkin Elmer). The
scintillation analysis was performed using Meltilex (Type A) solid
scintillator (Perkin Elmer). The solid scintillator was melted on
the filtermat at a temperature of 95 °C for 5 min. After solidifica-
tion of the scintillator at rt, the scintillation was measured using
a MicroBeta Trilux scintillation analyzer (Perkin Elmer). The overall
counting efficiency was 20%.
A solution of the secondary amine 7 (104 mg, 0.47 mmol), p-flu-
orobenzoyl chloride (108 mg, 0.68 mmol) and NEt3 (0.16 mL) in
CH2Cl2 (12 mL) was stirred for 1.5 h at rt. After addition of 2 M
NaOH (8 mL) the mixture was stirred for 1 h. The aqueous layer
was separated, extracted with CH2Cl2 (2ꢂ), the combined organic
layers were dried (Na2SO4) concentrated in vacuo and the residue
was purified by fc (3 cm, cyclohexane:ethyl acetate 7:3, 15 mL, Rf
0.20). Colorless solid, mp 109 °C, yield 142 mg (42%). C20H20FNO3
(341.4). MS (EI): m/z = 341 [M], 310 [M–OCH3], 292 [MꢁOCH3–F],
218 [MꢁO@CPhF], 123 [O@CPhF]. IR:
1620 (C@O amide), 1509 (aromat. C@C), 1219 (C–F), 1037 (C–O),
m
(cmꢁ1) = 2913 (C–H),