Molecules 2021, 26, 2770
8 of 13
stirred at r.t. for 2 h. After TLC showed disappearance of starting materials (hexane/diethyl
ether 6/1), the mixture was cooled in an ice bath and NaBH4 (16 mg, 0.43 mmol) was added
in portions. The ice bath was removed, and the mixture was stirred at r.t. for other 2 h.
After TLC showed the disappearance of the starting material (hexane/diethyl ether 6/1),
the solution was cooled in an ice bath and first acidified to pH = 2 by the addition of 1 M
HCl and the basified to pH = 14 by the addition of 8 M KOH. The solvent was evaporated
under reduced pressure. DCM (30 mL) was added, and the solution was washed with 1 M
KOH (3
×
10 mL), dried over magnesium sulphate and evaporated under reduced pressure,
obtaining a viscous liquid. The crude product was purified by column chromatography
(silica gel hexane/EtOAc, 9/1 with 0.5% TEA). The hydrochloride salt was then prepared,
dissolving the product in anhydrous diethyl ether and adding a 2 M solution of HCl in
diethyl ether dropwise.
1
White solid, 125 mg, 0.31 mmol, 86%. H-NMR (CDCl3, 400 MHz): 7.42–7.19 (m, 15H),
4.49 (dd, J = 7.9, 7.0 Hz, 1H), 3.0 (d, J = 3.4 Hz, 2H), 3.26 (dd, J = 12.6, 8.2 Hz, 1H), 3.16 (dd,
J = 12.6, 7.0 Hz, 1H); 13C{1H} NMR (CDCl3, 101 MHz): 140.7, 140.0, 135.4, 128.8, 128.6, 128.5,
128.4, 128.1, 127.9, 127.8, 127.2, 127.0, 53.4, 53.3, 48.2; (ESI+) m/z calcd for C21H22NSe+
[M + H]+: 368.08, found: 367.93.
3.7. Synthesis of Compound 6
Compound
dehyde (82 mg
9
(150 mg, 0.36 mmol) was dissolved in dry MeOH (6 mL). p-Nitrobenzal
µ
L, 0.36 mmol) was added to the solution that was deareated, purged with
nitrogen and stirred overnight at r.t. After TLC showed the disappearance of the starting
material (6/1 hexane/diethyl ether), the mixture was cooled in an ice bath and NaBH4
(16 mg, 0.43 mmol) was added portion wise. The ice bath was removed, and the mixture
was stirred at r.t. for other 2 h. After TLC showed the disappearance of the starting material
(6/1 hexane/diethyl ether), the solution was cooled in an ice bath and first acidified to
pH = 2 by the addition of 1 M HCl and the basified to pH = 14 by the addition of 8 M KOH.
The solvent was evaporated under reduced pressure. DCM (30 mL) was added, and the
solution was washed with 1 M KOH (3
×
10 mL), dried over magnesium sulphate and
evaporated under reduced pressure, obtaining a viscous liquid. The crude product was
purified by column chromatography (silica gel hexane/EtOAc, 9/1 with 0.5% TEA). The
hydrochloride salt was then prepared, dissolving the product in anhydrous diethyl ether
and adding a 2 M solution of HCl in diethyl ether dropwise.
1
White solid, 135 mg, 0.31 mmol, 87%. H-NMR (DMSO-d6, 400 MHz): δH (ppm) 9.56
(br, 1H), 9.25 (br, 1H), 8.24 (d, J = 8.9 Hz, 2H), 7.75 (d, J = 8.9 Hz, 2H), 7.44–7.42 (m, 2H),
7.36–7.25 (m, 8H), 4.88 (dd, J = 9.7, 5.6 Hz, 1H), 4.26 (s, 2H), 3.74–3.72 (m, 2H); 13C{1H} NMR
(DMSO-d6, 101 MHz): 148.2, 139.5, 138.2, 134.8, 134.0, 131.9, 129.8, 129.2, 128.7, 128.5, 128.4,
124.0, 50.5, 49.8, 42.2; (ESI+) m/z calcd for C21H21N2O2Se+ [M + H]+: 413.08, found: 412.89.
3.8. Synthesis of Compound 7
Compound 5 (100 mg, 0.27 mmol) was dissolved in iodoethane (5 mL). The solution
was deaerated, purged with nitrogen and refluxed under stirring at 90 ◦C for 2 h. After
TLC showed the disappearance of the starting material (hexane/diethyl ether, 6/1), the
mixture was cooled to r.t. and the solvent was evaporated under reduced pressure. DCM
(30 mL) was added, and the solution was washed with 1 M KOH (3
×
10 mL), dried
over magnesium sulphate and evaporated under reduced pressure obtaining a viscous
colorless liquid. The crude product was purified by column chromatography (silica gel,
hexane/EtOAc/TEA, 97/2.5/0.5) obtaining a viscous liquid. The hydrochloride salt was
then prepared dissolving the product in anhydrous diethyl ether and adding a 2 M solution
of HCl in diethyl ether dropwise.
1
White solid, 69 mg, 0.15 mmol, 57 %. H-NMR (CD3OD, 400 MHz): 7.51–7.06 (m, 15H),
4.77 (dd, J = 10.8, 4.7 Hz, 0.5H), 4.60 (dd, J = 10.5, 4.6 Hz, 0.5H), 4.39–4.22 (m, 2H), 4.06 (dd,
J = 13.9, 10.6 Hz, 0.5H), 3.88 (dd, J = 13.9, 10.7 Hz, 0.5H), 3.63–3.48 (m, 1H), 3.30–3.13 (m,
2H), 1.27–1.22 (m, 3H); 13C{1H} NMR (CD3OD, 101 MHz): 138.8, 138.3, 137.4, 137.3, 132.3,