2-H); 2.81 (1H, dt, J = 16.0 and J = 2.0, 6-H); 2.83 (1H, n. m, 3-H); 3.10 (1H, br. d, J = 11.0, 2-H); 3.44 (1H,
dd, J = 16.0 and J = 4.5, 6-H); 3.65 and 3.89 (1H and 1H, two dt, J = 9.9 and J = 2.5, 3-CH2O); 4.40 (1H, br. s,
13
OH); 6.13 (1H, n. m, 5-H); 7.25-7.42 (5H, m, Ph). C NMR spectrum, δ, ppm: 38.26 (Me); 45.31 (C(3)); 55.27
(C(2)); 58.07 (C(6)); 65.95 (CH2O); 124.48 (C(5)); 126.17, 127.33 and 128.47 (Ph); 136.2 and 139.9 (Cquat). Mass
spectrum, m/z (I, %): 203 (55) [M]+, 202 (17), 184 (6), 173 (19), 172 (100), 170 (54), 144 (23), 142 (16), 128
(21), 117 (19), 115 (28). Found, %: C 77.03; H 8.81; N 6.75. C13H17NO. Calculated, %: C 76.85; H 8.37;
N 6.90. The structure of alcohol 2 was established by X-ray structural analysis.
B. Aqueous 37% formaldehyde solution (0.5 g, 5.8 mmol) and 10% NaOH solution (1 ml) were added
to solution of THP 1 (1 g, 5.8 mmol) in benzene (50 ml), and then after 15 min activated MnO2 (5 g, 58 mmol)
was added. The mixture was stirred for 1 h 30 min at 20-40°C, then MnO2 was separated, and washed with hot
benzene (90 ml). The filtrates were evaporated, and after chromatographic separation of the residue the initial
compound 1 (0.37 g, 37%) and alcohol 2 (0.16 g, 22% calculated on reacted THP 1) were obtained .
C. Mixture of THP 1 (0.5 g, 2.9 mmol) with MnO2 (2.5 g, 29 mmol) in moist benzene (20 ml) was
stirred for 3 h at room temperature. According to TLC only the initial THP 1 was present in the reaction mixture
and was isolated in 84% yield (0.42 g) by the standard treatment. Replacement of benzene by other solvents
(acetone, ethanol, acetonitrile) did not lead to the oxidation of THP 1 under analogous conditions.
5-Hydroxymethyl-1-methyl-2-oxo-4-phenyl-1,2,3,6-tetrahydropyridine (3). Suspension of potassium
permanganate (0.4 g, 2.6 mmol) in water (2 ml) was added during 20 min to solution of alcohol 2 (0.35 g,
1.7 mmol) in acetonitrile (50 ml) and the mixture obtained was stirred for 1 h 30 min at room temperature. After
the standard treatment and chromatographic separation lactam 3 (0.19 g, 50%) and 4-phenylpyridine (0.027 g,
10%) were obtained. Lactam 3 was isolated as a colorless oil; Rf 0.65 (acetone). IR spectrum, ν, cm-1: 3370
1
(OH), 1642 and 1592 (NC=O and C=C). H NMR spectrum, δ, ppm: 3.0 (3H, s, Me); 3.05 (1H, m, 5-H); 3.55
(2H, m, 6-H); 3.67 (2H, m, 5-CH2O); 4.21 (1H, br. s, OH); 6.23 (1H, s, 3-H); 7.32 and 7.50 (3H and 2H, two m,
13
Ph). C NMR spectrum, δ, ppm: 34.33 (C(5)); 39.22 (Me); 48.35 (C(6)); 60.47 (CH2OH); 119.89 (C(3)); 126.07,
128.78, 129.6, and 150.09 (Ph); 136.0 (C(4)); 165.19 (C=O). Mass spectrum, m/z (I, %): 217 (60) [M]+, 186 (50),
185 (100). Found, %: C 71.4; H 7.38; N 6.12. C13H15NO2. Calculated, %: C 71.89; H 6.91; N 6.45.
1
Phenylpyridine 4 was obtained as colorless crystals of mp 76-78°C [9]. Rf 0.48 (acetone). H NMR
spectrum, δ, ppm (J, Hz): 7.36-7.70 (5H, m, Ph); 7.44 and 8.58 (2H and 2H, AA'BB' system, J = 5.8 and J = 1.6,
Het). Mass spectrum, m/z (I, %): 155 (100) [M]+, 128 (74), 127 (67), 115 (70), 102 (78).
3-Acetoxymethyl-1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (6a). Acetic anhydride (0.3 g,
1.98 mmol) was added to a cooled (0°C) solution of alcohol 2 (0.4 g, 1.98 mmol) in anhydrous pyridine (3 ml).
The mixture was maintained at room temperature for 48 h, then poured onto ice, and extracted with chloroform.
After chromatographic purification of the extract, acetate 6a (0.36 g, 75%) was isolated as a dense colorless oil
1
darkening with time; Rf 0.57 (acetone). IR spectrum, ν, cm-1: 1730 (C=O), 1640, 1596 (C=C). H NMR
spectrum, δ, ppm (J, Hz): 1.98 (3H, s, COMe); 2.30 (3H, s, NMe); 2.50 and 2.80 (1H and 1H, two dd,
J = 11 and 4.5 and J = 11 and 3.0 respectively, 2-CH2); 3.05 (1H, br. s, 3-H); 2.90 and 3.30 (1H and 1H, two
br. d, J = 18, 6-CH2); 4.03 (2H, m, 3-CH2O); 5.95 (1H, br. t, J = 3.0, 5-H); 7.10-7.40 (5H, m, Ph). Mass
spectrum, m/z (I, %): 245 (100) [M]+, 184 (76), 172 (99), 170 (30), 91 (35), 77 (19). Found, %: C 73.51; H 7.93;
N 5.77. C15H19NO2. Calculated, %: C 73.47; H 7.76; N 5.71.
1-Methyl-4-phenyl-3-propionyloxy-1,2,3,6-tetrahydropyridine (6b) was obtained in much the same
way from alcohol 2 (1.6 g, 7.88 mmol) and propionic anhydride (3 g, 23.6 mmol). Ester 6b (1.7 g, 85%) was
1
isolated as a viscous yellow oil. H NMR spectrum, δ, ppm (J, Hz): 1.10 and 2.25 (3H and 2H, t and q
respectively, J = 7.6, Et); 2.53 (3H, s, NMe); 2.92 (2H, d, J = 5, 2-H); 3.20-3.35 (3H, m, 3- and 6-H); 3.95-4.15
(2H, m, CH2O); 5.91 (1H, m, 5-H); 7.22-7.35 (5H, m, Ph). 13C NMR spectrum, δ, ppm: 9.37 and 27.3 (Et); 35.78
(NMe); 44.05 (C(3)); 53.10 and 53.33 (C(2) and C(6)); 122.92 (C(5)); 125.97, 127.58, 128.47 (Ph); 136.3 and 139.1
(C(4)); 174.1 (C=O). Mass spectrum, m/z (I, %): 259 (33) [M]+, 202 (11), 185 (41), 184 (100), 172 (97),
115 (30), 91 (46). Found, %: N 5.22. C16H21NO2. Calculated, %: N 5.41.
475