EXPERIMENTAL
The IR spectra were recorded on a UR 20 spectrometer in KBr disks, mass spectra were obtained on a MX
1303 instrument. The 1H NMR spectra were recorded on Bruker W 80 (80 MHz) and Bruker WM 250 (250 MHz)
instruments in CDCl3 solution, internal standard was TMS. A check on the progress of reactions and the
homogeneity of the compounds obtained was effected by TLC on Silufol UV-254 plates, visualization was with
iodine vapor. Separation and purification of substances was effected by column chromatography on silica gel L-60
(40/100).
1-Methyl-2-(4-nitrophenylimino)-4-phenyl-1,2,5,6-tetrahydropyridine (3). Finely powdered potassium
permanganate (0.91 g, 5.8 mmol) was added at room temperature during 20 min to a mixture consisting of
1-methyl-4-phenyltetrahydropyridine 1 (1 g, 5.8 mmol) and p-nitroaniline (0.95 g, 6.8 mmol) in acetonitrile
(50 ml). The mixture was stirred for 2 h, then the manganese dioxide was separated, and washed with acetonitrile
(3 × 10 ml). The filtrates were combined, and the solvent distilled off under reduced pressure. The residue was
separated on a column of silica gel (eluent hexane–ether, 2 : 1). On crystallization of the fraction with Rf 0.49
(acetone) amidine 3 (0.54 g, 30%) was obtained for the first time as a yellow amorphous powder; mp 92-94°C.
After storing the mother liquor for a month further amidine 3 (50 mg, 3%) was obtained as transparent monoclinic
1
bright yellow crystals of mp 118-120°C. Both portions of substance had identical IR and H NMR spectra and
chromatographic mobility. The structure of the crystalline sample was studied by X-ray analysis. A fraction with
Rf 0.17 (2% yield) was separated chromatographically and proved to be identical by mp (78-80°C) and spectral data
to the previously obtained 1-methyl-2-oxo-4-phenyltetrahydropyridine 4 [1,4]. On carrying out this reaction in the
cold (0°C) or with slight heating (35-50°C) the desired amidine 3 was obtained in less than 20% yield. IR spectrum,
, cm-1: 1339 and 1550 (NO2), 1624 and 1640 (C=C–C=N). Mass spectrum, m/z (Irel, %): 307 (100) (M+), 306 (44),
ν
1
259 (27), 250 (33), 230 (6), 187 (35), 166 (37), 149 (60). H NMR spectrum of amidine 3, , ppm, J (Hz): 2.88
δ
2
3
4
(2H, tt, 2J = 3J = 6.8, 4J = 1.2, 5-CH2); 3.15 (3H, s, Me); 3.53 (2H, t, J = J = 6.8, 6-CH2); 6.28 (1H, t, J = 1.2,
2
3
3-H); 6.9 and 8.16 (2H each, AA'BB' system of nitrophenyl fragment, J = 9.0, J = 2.0); 7.36 (5H, s, Ph).
Found, %: C 70.49; H 5.42; N 13.31. C18H17N3O2. Calculated, %: C 70.36; H 5.54; N 13.68.
1-Methyl-2-(4-nitrophenylimino)-4-([2.2]-paracyclophan-4-yl)-1,2,5,6-tetrahydropyridine (5) was
obtained analogously on oxidative imination of 1-methyl-4-(paracyclophan-4-yl)tetrahydropyridine 2 (1.0 g,
3.3 mmol) with p-nitroaniline (4.3 mmol). Compound 5 (0.42 g, 29%) was isolated as a yellow amorphous powder;
mp 114-117°C. Rf 0.37 (acetone). IR spectrum, , cm-1: 1335 and 1556, 1627. Mass spectrum: 437 (M+). 1H NMR
ν
spectrum, , ppm, J (Hz): 2.71 and 3.44 (2H each, both t, J = 6.4, 5-CH2 and 6-CH2); 2.7-3.2 (m, CH2 of
δ
paracyclophane); 3.13 (3H, s, Me); 5.9 (1H, s, 3-H); 6.0-6.6 (m, Harom paracyclophane portion); 6.88 and 8.1 (2H
each, both d, J = 8.6, AA'BB' system of nitrophenyl fragment). Found, %: C 76.70; H 6.11; N 9.87. C28H27N3O2.
Calculated, %: C 76.89; H 6.18; N 9.61.
2-(4-Bromophenylimino)-1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine (6) was obtained analogously
from a mixture of tetrahydropyridine 1 (1.0 g, 5.8 mmol) and p-bromoaniline (2.2 g, 12.8 mmol). The yield of
imine 6 was 0.34 g (17%) of needle-like light yellow crystals of mp 100-103°C. Rf 0.58 (ether). 1H NMR spectrum,
, ppm, J (Hz): 2.78 and 3.50 (2H each, both t, J = 6.4, 5-CH2 and 6-CH2); 3.08 (3H, s, Me); 6.27 (1H, br. s, 3-H);
δ
6.64 and 7.25 (2H each, both d, J = 8.3, AA'BB' system in p-bromophenyl fragment); 7.3 (5H, m, Ph). Found, %:
C 62.81; H 5.17; N 8.36. C18H17BrN2. Calculated, %: C 63.34; H 4.99; N 8.21.
1-Methyl-4-phenyl-2-[4-(phenylazo)phenyl]-1,2,5,6-tetrahydropyridine (7) was obtained analogously
from a mixture of tetrahydropyridine 1 (0.5 g, 2.9 mmol) and 4-aminoazobenzene (0.57 g, 2.9 mmol). Imine 7
(0.21 g, 20%) of mp 156-159°C was isolated chromatographically as orange prismatic crystals, Rf 0.52 (acetone).
IR spectrum: 1629 cm-1 (C=C–C=N). Mass spectrum: 366 (M+). 1H NMR spectrum, , ppm, J (Hz): 2.82 and 3.49
δ
(2H each, both t, J = 6.4, 5- and 6-CH2); 3.18 (3H, s, Me); 6.38 (1H, br. s, 3-H); 6.89 and 7.83 (2H each, both d,
J = 8.6, AA'BB' system); 7.2-7.5 (8H, m, 5H from C-Ph and 3H from N-Ph); 7.83 (2H, m, N-Ph). Found, %:
C 78.81; H 6.34; N 15.01. C24H22N4. Calculated, %: C 78.69; H 6.01; 15.30.
721
Soldatenkov
