L. Cheng, Z.-H. Shen, T.-M. Xu, C.-X. Tan, J.-Q. Weng, L. Han, W.-L. Peng, and X.-H. Liu
Vol 000
1H, Ph-H), 6.56 (s, 1H, Pyrazole-H), 3.65 (s, 3H, CH3),
3.36 (s, 3H, CH3), 2.34 (s, 3H, CH3); 13C-NMR
(150 MHz, CDCl3) δ 168.0, 151.0, 144.4, 135.4, 131.9,
130.9, 128.9, 126.8, 114.1, 111.6, 39.0, 38.1,13.5; ESI-
MS: 298 [M + 1]+, 300 [M + 3]+, 302 [M + 5]+, 320
[M + Na]+, 322 [M + Na + 2]+, 324 [M + Na + 4]+
(Ratio: 9:6:1). Anal. Calcd for C13H13Cl2N3O: C,
52.37; H, 4.39; N, 14.09. Found: C, 52.45; H, 4.44; N,
δ 167.9, 164.5, 143.6, 135.4, 131.9, 128.8, 122.0,
114.2, 111.6, 38.6, 37.9, 13.5; ESI-MS: 314 [M + 1]+,
336 [M + Na]+; Anal. Calcd for C14H14F3N3O2: C,
53.68; H, 4.50; N, 13.41. Found: C, 53.72; H, 4.68; N,
13.54.
N,1,3-trimethyl-N-(3-(trifluoromethyl)phenyl)-1H-pyrazole-4-
carboxamide (5i).
White solid, yield 83%, mp 145°C;
FT-IR (KBr, cmÀ1): ν 1703 (C═O), 1642, 1544, 1493,
1
1445, 1334, 1260, 1168, 1127, 1016, 888, 703; H-NMR
14.02.
(400 MHz, CDCl3) δ 7.55 (d, J = 7.7 Hz, 1H, Ph-H),
7.47 (d, J = 7.7 Hz, 1H, Ph-H), 7.46 (s, 1H, Ph-H),
7.21 (m, 1H, Ph-H), 6.42 (s, 1H, Pyrazole-H), 3.63 (s,
3H, CH3), 3.44 (s, 3H, CH3), 2.35 (s, 3H, CH3);
13C-NMR (150 MHz, CDCl3) δ 167.1, 164.6, 150.8,
145.5, 135.3, 131.9, 130.8, 123.9, 123.7, 122.5,
114.2, 38.6, 37.9, 13.4; ESI-MS: 298 [M + 1]+,
320 [M + Na]+. Anal. Calcd for C14H14F3N3O: C,
56.56; H, 4.75; N, 14.14. Found: C, 56.71; H, 4.88; N,
14.25.
N-(4-bromophenyl)-N,1,3-trimethyl-1H-pyrazole-4-carboxamide
(5e).
White solid, yield 83%, mp 131°C; FT-IR
(KBr, cmÀ1): ν 1697 (C=O), 1627, 1548, 1488, 1363,
1249, 1167, 1099, 1014, 720; 1H-NMR (400 MHz,
CDCl3) δ 7.47 (d, J = 8.3 Hz, 2H, Ph-H), 7.03
(d, J = 8.3 Hz, 2H, Ph-H), 6.44 (s, 1H, Pyrazole-H), 3.63
(s, 3H, CH3), 3.38 (s, 3H, CH3), 2.35 (s, 3H, CH3);
13C-NMR (150 MHz, CDCl3) δ 168.1, 151.9, 144.0,
135.4, 132.6, 128.9, 120.6, 114.3, 38.7, 38.0, 13.4;
ESI-MS: 308 [M + 1]+, 310 [M + 3]+, 330 [M + Na]+,
308 [M + Na + 2]+ (Ratio: 1:1); Anal. Calcd for
C13H14BrN3O: C, 50.67; H, 4.58; N, 13.64. Found: C,
Nematicidal evaluation.
The nematocidal activity
was determined according to our previous work [35–37].
Pure compounds (5a–5i) were dissolved with
dimethylformamide and diluted with distilled water to
obtain 40.0 mg/L concentrations for bioassays. The final
concentration of dimethylformamide in each treatment
never exceeded 1% v/v. The 1-week age tomato
seedlings were planted in sterilized sand in test tubes
(one seedling per test tube, tube size: 20 × 250 mm) and
treated the roots of each plant with 3 mL of test
solution. Then approximately 2000 living second-stage
juveniles of M. incognita were inoculated into the
rhizosphere sand of each plant. Avermectin at 5.0 mg/L
served as positive control, and the negative control
group was prepared in the same way but lacked the
tested compound. All the test tubes were incubated at
20–25°C for 20 days, with 10 h in the daylight per
day. The number of root knots of each plant was
counted and recorded a score. The inhibition rate on
M. incognita was calculated by comparison with the
negative control group:
50.78; H, 4.65; N, 13.65.
N,1,3-trimethyl-N-(p-tolyl)-1H–pyrazole-4-carboxamide
(5f). White solid, yield 86%, mp 111°C; FT-IR (KBr,
cmÀ1): ν 1698 (C═O), 1622, 1545, 1510, 1478, 1368,
1249, 1167, 1114, 1020, 828, 755, 721; 1H-NMR
(400 MHz, CDCl3) δ 7.15 (d, J = 7.9 Hz, 2H, Ph-H),
7.04 (d, J = 7.9 Hz, 2H, Ph-H), 6.26 (s, 1H, Pyrazole-
H), 3.58 (s, 3H, CH3), 3.38 (s, 3H, CH3), 2.38 (s, 3H,
CH3), 2.37 (s, 3H, CH3); 13C-NMR (150 MHz, CDCl3)
δ 168.0, 151.3, 142.3, 135.4, 132.2, 130.1, 127.2,
114.4, 39.0, 38.1, 21.0, 13.7; ESI-MS: 244 [M + 1]+,
266 [M + Na]+; Anal. Calcd for C14H17N3O: C,
69.11; H, 7.04; N, 17.27. Found: C, 69.23; H, 7.11; N,
17.14.
Methyl 4-(N,1,3-trimethyl-1H-pyrazole-4-carboxamido)benzoate
(5g). White solid, yield 82%, mp 101°C; FT-IR (KBr,
cmÀ1): ν 1713 (C═O), 1650, 1596, 1521, 1175, 1095,
772, 692; 1H-NMR (400 MHz, CDCl3)
δ 8.02
(d, J = 7.3 Hz, 2H, Ph-H), 7.66 (d, J = 7.3 Hz, 2H,
Ph-H), 7.60 (s, 1H, Pyrazole-H), 3.96–3.86 (m, 6H,
CH3), 3.45 (s, 3H, CH3), 2.55 (s, 3H, CH3); 13C-NMR
(150 MHz, CDCl3) δ 166.1, 164.5, 149.5, 148.9, 133.0,
130.5, 127.5, 127.2, 114.5, 52.6, 38.6, 37.7, 13.4;
ESI-MS: 288 [M + H]+. Anal. Calcd for C15H17N3O3:
C, 62.71; H, 5.96; N, 14.63. Found: C, 62.79; H, 5.89;
Inhibition rate(%) = (score of negative control À score
of treatment)/score of negative control 100%.
Scoring criteria: 0: 0–5 knots; 5: 6–10 knots; 10: 11–20
knots; 20: more than 20 knots.
N, 14.68.
CONCLUSION
N,1,3-trimethyl-N-(4-(trifluoromethoxy)phenyl)-1H-pyrazole-
4-carboxamide (5h). White solid, yield 86%, mp 170°C;
FT-IR (KBr, cmÀ1): ν 1701 (C═O), 1641, 1544, 1507,
1480, 1356, 1260, 1167, 1102, 1016, 856, 774, 720;
1H-NMR (400 MHz, CDCl3) δ 7.22 (d, J = 9.2 Hz,
2H, Ph-H), 7.19 (d, J = 9.1 Hz, 2H, Ph-H), 6.34
(s, 1H, Pyrazole-H), 3.60 (s, 3H, CH3), 3.41 (s, 3H,
CH3), 2.37 (s, 3H, CH3); 13C-NMR (150 MHz, CDCl3)
A series of N-alkyl pyrazole-4-carboxamide was
designed and synthesized. The modified pyrazole-
4-carboxamide possessed good nematocidal activity
against M. incognita. The mode of action was illustrated
using docking. These structures can be used as lead
compound for discover novel nematocides.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet