Chemistry of Heterocyclic Compounds 2020, 56(2), 173–179
residue was recrystallized from a mixture of PhMe–hexane.
130.1; 138.4; 141.0; 142.6; 144.0; 161.7; 176.9. Found, %:
C 74.22; H 4.86; N 9.89. C18H14N2O2. Calculated, %:
C 74.47; H 4.86; N 9.65.
Combined yield 0.158 g (62%), colorless crystals, mp 126–
127°С. IR spectrum, ν, cm–1: 3253, 3030, 1642, 1587,
1565, 1524, 1470, 1456, 1276, 1115, 967. 1H NMR
spectrum (400 MHz, DMSO-d6), δ, ppm (J, Hz): 2.39 (3H,
s, CH3); 2.41 (3H, s, CH3); 3.60 (2H, s, CH2); 5.47 (1H, d,
J = 7.4, =СН); 7.03–7.12 (2H, m, H Ar); 7.16–7.34 (6Н, m,
H Ar); 7.48 (1H, dd, J = 12.5, J = 7.4, =СНN); 10.12 (1Н,
s, NH); 11.42 (1Н, d, J = 12.5, NH). 13C NMR spectrum
(126 MHz, DMSO-d6), δ, ppm: 17.0; 17.8; 50.3; 96.9;
113.7; 123.2; 124.4; 124.9; 125.0; 125.9; 127.3; 130.3;
130.9; 131.1; 136.2; 138.2; 145.1; 165.7; 193.9. Found, %:
С 73.93; Н 6.47; N 9.24. C19H20N2O2. Calculated, %:
C 74.00; H 6.54; N 9.08.
N,1-Bis(4-methoxyphenyl)-4-oxo-1,4-dihydropyridine-
3-carboxamide (5c). Yield 0.084 g (74%), yellow powder,
mp 201–202°С (mp 201–202°С6). IR spectrum, ν, cm–1:
3074, 2902, 2835, 1677, 1608, 1552, 1504, 1236, 1018,
822. 1H and 13C NMR spectra correspond to those
described in the literature.6 1H NMR spectrum (400 MHz,
DMSO-d6), δ, ppm (J, Hz): 3.75 (3H, s, OCH3); 3.84 (3H, s,
OCH3); 6.65 (1H, d, J = 7.4, 5-СH); 6.88 (2H, d, J = 8.8, Н-3,5
ArNHC=О); 7.14 (2H, d, J = 8.9, Н-3,5 ArN); 7.56–7.67 (4H,
m, H Ar); 8.17 (1H, dd, J = 7.4, J = 2.4, 6-CH); 8.62 (1Н, d,
J = 2.4, 2-CH); 12.50 (1H, s, CONH).
(Z)-N-(4-Methoxyphenyl)-5-(4-methoxyphenylamino)-
3-oxopent-4-enamide (4f). The precipitated crystals were
filtered off. The product was recrystallized from a mixture
of PhMe–hexane. Yield 0.245 g (87%), yellow crystals,
mp 149–151°С (mp 152–153°С6). IR spectrum, ν, cm–1:
3301, 3009, 2832, 1636, 1568, 1025, 751. 1H NMR
spectrum (400 MHz, DMSO-d6), δ, ppm (J, Hz): 3.38 (2H,
s, CH2); 3.72 (3H, s, OCH3); 3.73 (3H, s, OCH3); 5.36 (1H,
d, J = 7.7, =CH); 6.88 (2H, d, J = 8.9, Н-3,5 ArNHC=C);
6.92 (2H, d, J = 8.9, Н-3,5 ArNHC=O); 7.21 (2H, d,
J = 8.9, Н-2,6 ArNHC=C); 7.51 (2H, d, J = 8.9, Н-2,6
ArNHC=O); 7.62 (1Н, dd, J = 12.7, J = 7.7, =СН); 9.96
(1H, s, CONH); 11.46 (1H, d, J = 12.7, NH). Found, %:
C 67.08; H 6.05; N 8.09. C19H20N2O4. Calculated, %:
C 67.05; H 5.92; N 8.23.
Synthesis of 4-oxo-1,4-dihydropyridine-3-carbox-
amides 5а–с (General method). Enaminone 4c,d,f
(0.325 mmol) and N,N-dimethylformamide dimethyl acetal
(0.078 g, 0.65 mmol) in anhydrous PhMe (1 ml) were
stirred at room temperature for 24 h. The formed
precipitate was filtered off and washed with hexane.
(Z)-2-[(4-Bromophenyl)(piperidin-1-yl)methyl]-3-oxo-
N-phenyl-5-(phenylamino)pent-4-enamide (6). Enaminone
4d (100 mg, 0.357 mmol), p-bromobenzaldehyde (72.6 mg,
0.393 mmol), and piperidine (36.5 mg, 0.428 mmol) in
anhydrous MeCN (2 ml) were stirred at room temperature
for 2 days. The formed precipitate was filtered off. Yield
0.144 g (76%), yellow powder, mp 145–146°С. IR spect-
rum, ν, cm–1: 3273, 2939, 2809, 2756, 1678, 1627, 1598,
1
1479, 1274, 1128, 973. H NMR spectrum (500 MHz,
DMSO-d6), δ, ppm (J, Hz): 1.10–1.21 (2H, m, CH2); 1.25–
1.43 (4H, m, CH2); 2.01–2.19 (2H, m, CH2); 2.42–2.52
(2H, m, CH2); 4.43 (1Н, d, J = 11.9, CH); 4.52 (1Н, d,
J = 11.9, CH); 5.47 (1Н, d, J = 7.7, =CH); 7.01 (1H, t,
J = 7.3, Н-4 Ph); 7.07 (1H, t, J = 7.4, Н-4 Ph); 7.14 (2H, d,
J = 8.3, H Ph, H Ar); 7.16 (2H, d, J = 8.1, H Ph, H Ar); 7.28
(2H, t, J = 8.0, Н-3,5 Ph); 7.33 (2H, t, J = 7.9, Н-3,5 Ph);
7.53 (2H, d, J = 8.3, H Ph, H Ar); 7.59 (1H, dd, J = 12.7,
J = 7.7, =CH); 7.61 (2H, d, J = 7.8, H Ph, H Ar); 10.26
(1H, s, NH); 11.13 (1H, d, J = 12.7, NH). 13C NMR
spectrum (126 MHz, DMSO-d6) (selected signals), δ, ppm:
24.1; 26.1; 50.1; 60.7; 61.5; 96.7; 115.5; 119.0; 122.2;
123.7; 128.8; 129.5; 130.4; 130.5; 130.7; 134.6; 139.2;
140.8; 144.5; 166.9; 189.8. Found, %: C 65.67; H 5.86;
N 8.03. C29H30BrN3O2. Calculated, %: C 65.41; H 5.68;
N 7.89.
N,1-Dibenzyl-4-oxo-1,4-dihydropyridine-3-carbox-
amide (5a). Yield 0.083 g (80%), gray powder, mp 125–
127°С (mp 129–130°С6). IR spectrum, ν, cm–1: 3088, 3074,
1
1662, 1622, 1547, 1489, 1187, 839. H NMR spectrum
(400 MHz, DMSO-d6), δ, ppm (J, Hz): 4.51 (2Н, d, J = 6.0,
PhCH2NH); 5.31 (2H, s, PhCH2N); 6.47 (1Н, d, J = 7.6,
5-CH); 7.20–7.43 (10Н, m, H Ph); 7.96 (1Н, dd, J = 7.6,
J = 2.4, 6-CH); 8.67 (1Н, d, J = 2.4, 2-CH); 10.65 (1Н, t,
J = 6.0, NH). 13C NMR spectrum (126 MHz, DMSO-d6),
δ, ppm: 42.0; 59.0; 118.5; 120.2; 127.3; 127.8; 128.4 (2C);
129.0; 136.2; 139.3; 141.4; 144.8; 163.8; 176.5 (1C not
detected). Found, %: C 75.39; H 5.69; N 8.91. C20H18N2O2.
Calculated, %: C 75.45; H 5.70; N 8.80.
4-Oxo-N,1-diphenyl-1,4-dihydropyridine-3-carbox-
amide (5b). Yield 0.082 g (87%), yellow powder, mp 134–
135°С. IR spectrum, ν, cm–1: 3098, 2961, 1686, 1629, 1598,
1544, 1488, 1294, 1230, 833. 1H NMR spectrum (500 MHz,
DMSO-d6), δ, ppm (J, Hz): 6.69 (1H, d, J = 7.5, 5-CH);
7.11 (1H, t, J = 7.4, Н-4 Ph); 7.37 (2H, t, J = 7.9, Н-3,5
Ph); 7.56 (1H, tt, J = 7.4, J = 1.1, Н-4 Ph); 7.63 (2H, t,
J = 8.1, Н-3,5 Ph); 7.67–7.73 (4Н, m, H Ph); 8.27 (1Н, dd,
J = 7.5, J = 2.5, 6-CH); 8.71 (1Н, d, J = 2.5, 2-CH); 12.62
(1H, s, CONH). 13C NMR spectrum (126 MHz, DMSO-d6),
δ, ppm: 118.5; 119.7; 120.2; 123.3; 123.8; 128.9; 129.1;
(Pyrazol-3-yl)acethydrazide (7). Hydrazine hydrate
(0.330 g, 6.60 mmol) in MeOH (1 ml) was added with
stirring to a solution of 2-cyano-4-pyrone (3) (0.200 g,
1.65 mmol) in MeOH (1 ml) with cooling in ice bath. The
reaction mixture was stirred with cooling for 1 h and at
room temperature for 12 h. The precipitate was filtered off
and washed with cold EtOH. Yield 0.151 g (65%),
colorless powder, mp 181–182°С (mp 181–183°С13).
IR spectrum, ν, cm–1: 3276, 3133, 2881, 1649, 1620, 1533,
1171, 757. 1H NMR spectrum (400 MHz, DMSO-d6),
δ, ppm: 3.35 (2Н, s, CH2); 4.20 (2H, br. s, NH2); 6.10 (1H,
br. s, H-4 pyrazole); 7.24–7.65 (1H, br. s, H-5 pyrazole);
9.09 (1H, br. s, NHNH2); 12.51 (1H, br. s, NH). 13C NMR
spectrum (126 MHz, DMSO-d6), δ, ppm: major NH-tauto-
mer: 33.7; 103.9; 128.7; 146.0; 169.0; minor NH-tautomer:
30.8; 136.5; 168.1.
N'-Phenyl-2-(1-phenyl-1H-pyrazol-5-yl)acethydrazide (8)
was not isolated as an individual substance. 2-Cyano-
4-pyrone (3) (0.100 g, 0.83 mmol) and phenylhydrazine
(0.196 g, 1.82 mmol) were mixed in MeOH (1 ml) in ice
177