Catalysis Science & Technology
Page 4 of 6
ARTICLE
DOI: 10.1039/C5CY00137D
(s, 1H), 9.60 (s, 1H). FTꢀIR (KBr): 3630, 3410, 3340, 3315, C10H8Cl2N2O: C, 49.41; H, 3.32; N, 11.52. Found: C, 49.31; H,
3100, 1620, 1430, 1527, 1060, 780, 610 cmꢀ1
3.17; N, 11.30.
4.2 General procedure for the regioselective halogenation of 1-
Aryl-3-methyl-1H-pyrazol-5(4H)-ones catalyzed by Pd(NHC)Cl2
4.3.5 1-(2-bromophenyl)-3-methyl-1H-pyrazol-5(4H)-one (3a)
1H NMR (400 MHz, CDCl3): δ (ppm) 2.22 (s, 3H), 3.46 (s,
2H), 7.15ꢀ7.18 (m, 1H), 7.32 (t, 1H), 7.83ꢀ7.86 (m, 1H), 7.95 (t,
1H), 13C NMR (100 MHz, CDCl3): δ (ppm) 17.02 (CH3), 43.12
(CH2), 116.47, 118.62, 124.87, 129.88, 134.57, 139.09, 156.63
(C=N), 170.53 (C=O), FTꢀIR (KBr): 3110, 2813, 1625 (C=O
str.), 1580 (C=N str.), 1480, 1318, 1215, 1031, 969 cmꢀ1, Anal.
Calcd. for C10H9BrN2O: C, 47.46; H, 3.58; N, 11.07. Found: C,
47.40; H, 3.42; N, 10.98.
A mixture of 1ꢀArylꢀ3ꢀmethylꢀ1Hꢀpyrazolꢀ5(4H)ꢀones (1 mmol),
NXS (X = Cl or Br, 1.1 mmol), Ag2O (0.5 mmol) and
Pd(NHC)Cl2 complex (5 mol %) in 2 mL acetonitrile was
magnetically stirred at 80 ºC for the required time. The solvent
was removed under vacuum and the resulting residues were
purified by chromatography on silica gel column by using
hexane : ethyl acetate (20 : 1, v/v) as eluent to afford the
desired products
.
4.3.6 1-(2-bromo-5-chlorophenyl)-3-methyl-1H-pyrazol-5(4H)-
one (3b)
1H NMR (400 MHz, CDCl3): δ (ppm) 2.20 (s, 3H), 3.43 (s,
2H), 7.31 (dd, J = 2.4, Hz, J
= 8.8 Hz, 1H), 7.44 (t, 2H), 13C
4.3 Spectral data
4.3.1 1-(2-chlorophenyl)-3-methyl-1H-pyrazol-5(4H)-one (2a)
1H NMR (400 MHz, CDCl3): δ (ppm) 2.21 (s, 3H), 3.44 (s,
2H), 7.33ꢀ7.38 (m, 2H), 7.42ꢀ7.45 (m, 1H), 7.51ꢀ7.53 (m, 1H),
13C NMR (100 MHz, CDCl3): δ (ppm) 17.15 (CH3), 41.47
(CH2), 127.56, 128.85, 129.85, 130.56, 131.82, 134.44, 156.60
(C=N), 171.26 (C=O), FTꢀIR (KBr): 3104, 2810, 1623 (C=O
str.), 1585 (C=N str.), 1494, 1311, 1218, 1035, 964 cmꢀ1, Anal.
Calcd. for C10H9ClN2O: C, 57.57; H, 4.35; N, 13.43. Found: C,
57.49; H, 4.26; N, 13.40.
NMR (100 MHz, CDCl3): δ (ppm) 17.15 (CH3), 41.42 (CH2),
120.00, 128.67, 129.74, 129.98, 131.35, 135.35, 157.06 (C=N),
170.96 (C=O), FTꢀIR (KBr): 3107, 2811, 1625 (C=O str.), 1582
(C=N str.), 1481, 1315, 1214, 1030, 969 cmꢀ1, Anal. Calcd. for
C10H8BrClN2O: C, 41.77; H, 2.80; N, 9.74. Found: C, 41.57; H,
2.71; N, 9.55.
4.3.7 1-(2-bromo-4-methylphenyl)-3-methyl-1H-pyrazol-5(4H)-
one (3c)
1H NMR (400 MHz, CDCl3): δ (ppm) 2.21 (s, 3H), 2.36 (s,
4.3.2 1-(2,5-dichlorophenyl)-3-methyl-1H-pyrazol-5(4H)-one (2b)
1H NMR (400 MHz, CDCl3): δ (ppm) 2.21 (s, 3H), 3.43 (s,
2H), 7.31 (dd, J = 2.8 Hz, J
= 8.4 Hz, 1H), 7.45 (t, 2H), 13C
3H), 3.44 (s, 2H), 7.18ꢀ7.27 (m, 2H), 7.74 (d,
J = 4.4 Hz, 1H),
13C NMR (100 MHz, CDCl3): δ (ppm) 17.04 (CH3), 20.96(Arꢀ
CH3), 43.07 (CH2), 128.67, 119.00, 120.90, 129.35, 134.77,
134.78, 135.60, 156.15 (C=N), 170.44 (C=O), FTꢀIR (KBr):
3108, 2810, 1622 (C=O str.), 1585 (C=N str.), 1480, 1315,
1212, 1030, 967 cmꢀ1, Anal. Calcd. for C11H11BrN2O: C, 49.46;
H, 4.15; N, 10.49. Found: C, 49.41; H, 3.97; N, 10.34.
NMR (100 MHz, CDCl3): δ (ppm) 17.15 (CH3), 41.42 (CH2),
128.67, 129.74, 129.98, 131.35, 132.95, 135.36, 157.04 (C=N),
170.95 (C=O), FTꢀIR (KBr): 3101, 2810, 1629 (C=O str.), 1582
(C=N str.), 1489, 1308, 1210, 1032, 967 cmꢀ1, Anal. Calcd. for
C10H8Cl2N2O: C, 49.41; H, 3.32; N, 11.52. Found: C, 49.39; H,
3.18; N, 11.36.
4.3.8 1-(2-bromo-4-chlorophenyl)-3-methyl-1H-pyrazol-5(4H)-
one (3d)
1H NMR (400 MHz, CDCl3): δ (ppm) 2.21 (s, 3H), 3.43 (s,
2H), 7.33 (dd, J = 2.4, Hz, J
= 8.8 Hz, 1H), 7.44 (t, 2H), 13C
4.3.3 1-(2-chloro-4-methylphenyl)-3-methyl-1H-pyrazol-5(4H)-
one (2c)
1H NMR (400 MHz, CDCl3): δ (ppm) 2.21 (s, 3H), 2.36 (s,
NMR (100 MHz, CDCl3): δ (ppm) 16.22 (CH3), 44.51 (CH2),
116.57, 123.42, 130.06, 134.46, 145.01, 157.04 (C=N), 169.26
(C=O), FTꢀIR (KBr): 3102, 2810, 1625 (C=O str.), 1585 (C=N
str.), 14804, 1314, 1210, 1032, 968 cmꢀ1, Anal. Calcd. for
C10H8BrClN2O: C, 41.77; H, 2.80; N, 9.74. Found: C, 41.67; H,
2.69; N, 9.65.
3H), 3.44 (s, 2H), 7.28ꢀ7.35 (m, 2H), 7.73 (d,
J = 3.6 Hz, 1H),
13C NMR (100 MHz, CDCl3): δ (ppm) 17.05 (CH3), 20.97(Arꢀ
CH3), 43.08 (CH2), 128.67, 119.00, 126.06, 129.36, 134.78,
135.59, 145.10, 156.17 (C=N), 170.45 (C=O), FTꢀIR (KBr):
3107, 2810, 1625 (C=O str.), 1580 (C=N str.), 1484, 1315,
1214, 1032, 969 cmꢀ1, Anal. Calcd. for C11H11ClN2O: C, 59.33;
H, 4.98; N, 12.58. Found: C, 59.22; H, 4.72; N, 12.35
4.3.9 1-(4-chlorophenyl)-3-methyl-1H-pyrazol-5(4H)-one (2a’)
1H NMR (400 MHz, CDCl3): δ (ppm) 2.22 (s, 3H), 3.46 (s,
4.3.4 1-(2,4-dichlorophenyl)-3-methyl-1H-pyrazol-5(4H)-one (2d)
1H NMR (400 MHz, CDCl3): δ (ppm) 2.19 (s, 3H), 3.50 (s,
2H), 7.98 (t, 1H), 8.33 (m, 1H), 9.15 (d, J
= 2.4 Hz, 1H), 13C
2H), 7.36
(dd, J = 2.4, Hz, J = 7.2 Hz, 2H), 7.86 (dd, J = 2.0,
Hz,
J
= 6.8 Hz, 2H), 13C NMR (100 MHz, CDCl3): δ (ppm)
17.06 (CH3), 43.10 (CH2), 119.87, 128.87, 131.59, 135.99,
156.19 (C=N), 170.45 (C=O), FTꢀIR (KBr): FTꢀIR (KBr):
3110, 2815, 1620 (C=O str.), 1582 (C=N str.), 1486, 1315,
1210, 1032, 966 cmꢀ1, Anal. Calcd. for C10H9ClN2O: C, 57.57;
H, 4.35; N, 13.43. Found: C, 57.51; H, 4.22; N, 13.13.
NMR (100 MHz, CDCl3): δ (ppm) 17.15 (CH3), 41.42 (CH2),
128.68, 129.76, 129.98, 131.35, 132.95, 135.36, 157.04 (C=N),
170.95 (C=O), FTꢀIR (KBr): 3109, 2811, 1629 (C=O str.), 1583
(C=N str.), 1485, 1320, 1213, 1035, 967 cmꢀ1, Anal. Calcd. for
4 | J. Name., 2012, 00, 1-3
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