26 JOURNAL OF CHEMICAL RESEARCH 2018
7.04–6.89 (m, 2H), 3.92 (t, J = 7.9 Hz, 2H), 2.58 (t, J = 7.9 Hz, 2H);
MS (ESI) m/z: 197.4 (M + 1). Anal. calcd for C9H9ClN2O (196.63): C,
54.97; H, 4.61; N, 14.25; found: C, 55.21; H, 4.53; N, 14.09%.
+ 1). Anal. calcd for C15H13ClN2O (272.73): C, 66.06; H, 4.80; N, 10.27;
found: C, 66.30; H, 4.62; N, 10.09%.
1-(4-Bromophenyl)-5-phenylpyrazolidin-3-one (2l): White powder;
yield 72%; m.p. 169–171 °C; IR (KBr) (ν cm−1): 1692 (C=O); 1H NMR
(600 MHz, CDCl3): δ 9.23 (s, 1H), 7.46–7.33 (m, 7H), 6.92–6.83 (m,
2H), 4.86 (dd, J = 9.3, 3.9 Hz, 1H), 3.28 (dd, J = 17.0, 9.3 Hz, 1H), 2.56
(dd, J = 16.9, 3.9 Hz, 1H); MS (ESI) m/z: 317.04 (M + 1). Anal. calcd
for C15H13BrN2O (316.02): C, 56.80; H, 4.13;N, 8.83; found: C, 56.59;
H, 4.20; N, 8.69%.
1-(4-Bromophenyl)pyrazolidin-3-one (2b): Pale yellow solid; yield
1
80%; m.p. 123–125 °C; IR (KBr) (ν cm−1): 1680 (C=O); H NMR
(600 MHz, CDCl3): δ 7.87 (s, 1H), 7.42 (d, J = 8.7 Hz, 2H), 6.93 (d,
J = 8.8 Hz, 2H), 3.94 (t, J = 7.9 Hz, 2H), 2.56 (t, J = 7.8 Hz, 2H); MS
(ESI) m/z: 241.07 (M + 1). Anal. calcd for C9H9BrN2O (239.99): C,
44.84; H, 3.76; N, 11.62; found: C, 44.99; H, 3.55; N, 11.68%.
1-(4-Fluorophenyl)pyrazolidin-3-one (2c): Pale yellow solid; yield
1-(4-Fluorophenyl)-5-phenylpyrazolidin-3-one
(2m):
White
1
76%; m.p. 109–111 °C; IR (KBr) (ν cm−1): 1637 (C=O); H NMR
powder; yield 72%; m.p. 158–160 °C; IR (KBr) (ν cm−1): 1692 (C=O);
1H NMR (600 MHz, CDCl3): δ 9.32 (s, 1H), 7.47–7.30 (m, 5H), 7.20
(d, J = 8.3 Hz, 2H), 6.92 (d, J = 8.3 Hz, 2H), 4.85 (dd, J = 9.4, 3.8 Hz,
1H), 3.27 (dd, J = 16.9, 9.3 Hz, 1H), 2.55 (dd, J = 16.9, 4.0 Hz, 1H);
MS (ESI) m/z: 255.04 (M − 1). Anal. calcd for C15H13FN2O (256.10): C,
70.30; H, 5.11; N, 10.93; found: C, 70.44; H, 5.20; N, 10.80%.
1,5-Diphenylpyrazolidin-3-one (2n): White powder; yield 77%; m.p.
159–161 °C (lit.23 158–159 °C).
(600 MHz, CDCl3): δ 8.97 (s, 1H), 7.01 (d, J = 6.4 Hz, 4H), 3.87 (t,
J = 7.9 Hz, 2H), 2.57 (t, J = 7.9 Hz, 2H); MS (ESI) m/z: 181.1 (M + 1).
Anal. calcd for C2H9FN2O (180.07): C, 59.99; H, 5.03;N, 15.55; found:
C, 60.31; H, 4.98; N, 15.40%.
1-Phenylpyrazolidin-3-one (2d): Pale yellow solid; yield 75%; m.p.
1
118–120 °C (lit.17 121 °C); IR (KBr) (ν cm−1): 1688 (C=O); H NMR
(600 MHz, CDCl3): δ 8.92 (s, 1H), 7.36–7.23 (m, 2H), 7.12–6.94 (m,
3H), 3.94 (t, J = 7.9 Hz, 2H), 2.57 (t, J = 8.0 Hz, 2H); MS (ESI) m/z:
163.0 (M + 1). Anal. calcd for C9H10N2O (162.19): C, 66.65; H, 6.21; N,
17.27; found: C, 66.48; H, 6.11; N, 17.20%.
1-p-Tolylpyrazolidin-3-one (2e): Pale yellow solid; yield 82%;
m.p.150–152 °C (lit.22 150–152 °C); IR (KBr) (ν cm−1): 1689 (C=O);
1H NMR (600 MHz, CDCl3): δ 7.11 (d, J = 8.3 Hz, 2H), 7.02–6.79 (m,
2H), 3.87 (t, J = 7.9 Hz, 2H), 2.54 (t, J = 7.9 Hz, 2H), 2.30 (s, 3H); MS
(ESI) m/z: 177.1 (M + 1). Anal. calcd for C10H12N2O (176.22): C, 68.16;
H, 6.86; N, 15.90; found: C, 68.23; H, 6.78; N, 15.98%.
5-Phenyl-1-p-tolylpyrazolidin-3-one (2o): White powder; yield 81%;
m.p. 144–146 °C (lit.23 144–145 °C).
Synthesis of 4-iodopyrazol-3-ols (3a–o); general procedure
A mixture of CH2Cl2 (10 mL), H2SO4 (0.01 mol), intermediates 2
(0.01 mol) and KI (0.01 mol) was stirred at room temperature. Then,
30% H2O2 (0.02 mol) was added dropwise. The mixture was stirred at
room temperature for 2 h and the product 3 directly crystallised from
the CH2Cl2. Then 5% NaHSO3 (5 mL) was added to the mixture. The
suspension was filtered off and washed, and the products were purified
by recrystallisation from methanol.
1-(4-Chlorophenyl)-4-iodo-1H-pyrazol-3-ol (3a): Pale yellow solid;
yield 89%; m.p. 177–179 °C; IR (KBr) (ν cm−1): 3450 (OH); 1H NMR
(600 MHz, DMSO-d6): δ 10.99 (s, 1H), 8.47 (s, 1H), 7.71 (d, J = 8.9 Hz,
2H), 7.50 (d, J = 8.8 Hz, 2H); MS (ESI) m/z: 321.6 (M + 1). Anal. calcd
for C9H6ClIN2O (320.51): C, 33.73; H, 1.89; N, 8.74; found: C, 33.91; H,
1.73; N, 8.56%.
1-(4-Chlorophenyl)-5-methylpyrazolidin-3-one
(2f):
Pale
yellow solid; yield 70%; m.p. 112–114 °C; IR (KBr) (ν cm−1): 1698
(C=O); 1H NMR (600 MHz, CDCl3): δ 8.33 (s, 1H), 7.31–7.24
(m, 2H), 7.12–6.92 (m, 2H), 3.95 (ddd, J = 7.9, 6.7, 2.1 Hz, 1H),
2.90 (dd, J = 16.6, 8.0 Hz, 1H), 2.02 (dd, J = 16.6, 2.2 Hz, 1H), 1.46
(d, J = 6.7 Hz, 3H); MS (ESI) m/z: 211.7 (M + 1). Anal. calcd for
C10H11ClN2O (210.66): C, 57.01; H, 5.26; N, 13.30; found: C, 57.31; H,
5.04; N, 13.13%.
1-(4-Bromophenyl)-4-iodo-1H-pyrazol-3-ol (3b): Pale yellow solid;
yield 89%; m.p. 180–182 °C; IR (KBr) (ν cm−1): 3451 (OH); 1H NMR
(600 MHz, DMSO-d6): δ 10.99 (s, 1H), 8.48 (s, 1H), 7.79–7.57 (m, 4H);
MS (ESI) m/z: 365.9 (M + 1). Anal. calcd for C9H6BrIN2O (364.97): C,
29.62; H, 1.66; N, 7.68; found: C, 29.80; H, 1.71; N, 7.49%.
1-(4-Fluorophenyl)-4-iodo-1H-pyrazol-3-ol (3c): Pale yellow solid;
yield 89%; m.p. 171–173 °C; IR (KBr) (ν cm−1): 3450 (OH); 1H NMR
(600 MHz, DMSO-d6): δ 10.88 (s, 1H), 8.41 (s, 1H), 7.74–7.67 (m,
2H), 7.33–7.25 (m, 2H); MS (ESI) m/z: 305.1 (M + 1). Anal. calcd for
C9H6FIN2O (304.04): C, 35.55; H, 1.99; N, 9.21; found: C, 35.88; H,
1.68; N, 9.01%.
4-Iodo-1-phenyl-1H-pyrazol-3-ol (3d): Pale yellow solid; yield 89%;
m.p. 167–169 °C (lit.24 168–170 °C); IR (KBr) (ν cm−1): 3450 (OH);
1H NMR (600 MHz, DMSO-d6): δ 10.92 (s, 1H), 8.45 (s, 1H), 7.70 (d,
J = 7.5 Hz, 2H), 7.52–7.33 (m, 2H), 7.22 (t, J = 7.4 Hz, 1H); MS (ESI)
m/z: 287.1 (M + 1). Anal. calcd for C9H7IN2O (286.07): C, 37.79; H,
2.47; N, 9.79; found: C, 37.61; H, 2.33; N, 9.58%.
4-Iodo-1-p-tolyl-1H-pyrazol-3-ol (3e): Pale yellow solid; yield 89%;
m.p. 169–171 °C; IR (KBr) (ν cm−1): 3452 (OH); 1H NMR (600 MHz,
CDCl3): δ 7.66 (s, 1H), 7.35 (d, J = 8.4 Hz, 2H), 7.28–7.24 (m, 2H),
2.38 (s, 3H); MS (ESI) m/z: 301.2 (M + 1). Anal. calcd for C10H9IN2O
(300.10): C, 40.02; H, 3.02; N, 9.33; found: C, 39.91; H, 3.18; N, 9.24%.
1-(4-Chlorophenyl)-4-iodo-5-methyl-1H-pyrazol-3-ol (3f): White
powder; yield 89%; m.p. 197–199 °C; IR (KBr) (ν cm−1): 3452 (OH);
1H NMR (600 MHz, DMSO-d6): δ 10.69 (s, 1H), 7.58–7.46 (m, 4H),
2.30 (s, 3H); MS (ESI) m/z: 335.6 (M + 1). Anal. calcd for C10H8ClIN2O
(334.54): C, 35.90; H, 2.41; N, 8.37; found: C, 35.61; H, 2.75; N, 8.02%.
1-(4-Bromophenyl)-4-iodo-5-methyl-1H-pyrazol-3-ol (3g): White
powder; yield 89%; m.p. 211–213 °C; IR (KBr) (ν cm−1): 3446 (OH);
1H NMR (600 MHz, DMSO-d6): δ 10.70 (s, 1H), 7.67 (d, J = 8.8 Hz,
2H), 7.43 (d, J = 8.8 Hz, 2H), 2.30 (s, 3H); MS (ESI) m/z: 380.0 (M +
1). Anal. calcd for C10H8BrIN2O (378.99): C, 31.69; H, 2.13; N, 7.39;
found: C, 31.81; H, 2.09; N, 7.28%.
1-(4-Bromophenyl)-5-methylpyrazolidin-3-one (2g): Pale yellow
solid; yield 75%; m.p. 120–122 °C; IR (KBr) (ν cm−1): 1707 (C=O);
1H NMR (600 MHz, CDCl3): δ 8.79 (s, 1H), 7.39 (d, J = 8.8 Hz, 2H),
6.92 (d, J = 8.8 Hz, 2H), 4.06–3.85 (m, 1H), 2.90 (dd, J = 16.6, 8.1 Hz,
1H), 2.02 (dd, J = 16.6, 2.1 Hz, 1H), 1.45 (d, J = 6.7 Hz, 3H); MS (ESI)
m/z: 255.08 (M + 1). Anal. calcd for C10H11BrN2O (254.01): C, 47.08; H,
4.35; N, 10.98; found: C, 47.22; H, 4.45; N, 10.83%.
1-(4-Fluorophenyl)-5-methylpyrazolidin-3-one (2h): Pale yellow
solid; yield 77%; m.p. 107–109 °C; IR (KBr) (ν cm−1): 1666 (C=O);
1H NMR (600 MHz, CDCl3): δ 8.35 (s, 1H), 7.29–7.24 (m, 2H),
7.05–6.97 (m, 2H), 4.00–3.89 (m, 1H), 2.90 (dd, J = 16.5, 8.0 Hz, 1H),
2.02 (dd, J = 16.5, 2.2 Hz, 1H), 1.46 (d, J = 6.8 Hz, 3H); MS (ESI) m/z:
195.1 (M + 1). Anal. calcd for C10H11FN2O (194.21): C, 61.85; H, 5.71;
N, 14.42; found: C, 61.71; H, 5.60; N, 14.33%.
5-Methyl-1-phenylpyrazolidin-3-one (2i): Pale yellow solid; yield
81%; m.p. 125–127 °C (lit.21 127 °C); IR (KBr) (ν cm−1): 1696 (C=O);
1H NMR (600 MHz, CDCl3): δ 8.47 (s, 1H), 7.37–7.25 (m, 2H),
7.18–6.93 (m, 3H), 4.07–3.93 (m, 1H), 2.91 (dd, J = 16.5, 8.0 Hz, 1H),
2.01 (dd, J = 16.5, 2.2 Hz, 1H), 1.46 (d, J = 6.8 Hz, 3H); MS (ESI) m/z:
177.2 (M + 1). Anal. calcd for C10H12N2O (176.22): C, 68.16; H, 6.86; N,
15.90; found: C, 68.20; H, 6.81; N, 15.87%.
5-Methyl-1-p-tolylpyrazolidin-3-one (2j): Pale yellow solid; yield
1
75%; m.p. 117–119 °C; IR (KBr) (ν cm−1): 1690 (C=O); H NMR
(600 MHz, CDCl3): δ 8.11 (s, 1H), 7.20–7.05 (m, 2H), 7.03–6.84 (m,
2H), 3.90 (dd, J = 7.9, 6.7, 2.5 Hz, 1H), 2.88 (dd, J = 16.5, 8.0 Hz, 1H),
2.31 (s, 3H), 1.99 (dd, J = 16.5, 2.6 Hz, 1H), 1.44 (d, J = 6.7 Hz, 3H);
MS (ESI) m/z: 191.3 (M + 1). Anal. calcd for C11H14N2O (190.24): C,
69.45; H, 7.42; N, 14.73; found: C, 69.32; H, 7.29; N, 14.69.
1-(4-Chlorophenyl)-5-phenylpyrazolidin-3-one (2k): White powder;
yield 69%; m.p. 160–162 °C; IR (KBr) (ν cm−1): 1690 (C=O); 1H NMR
(600 MHz, CDCl3): δ 8.69 (s, 1H), 7.50–7.31 (m, 5H), 7.27–7.20
(m, 2H), 7.01–6.92 (m, 2H), 4.87 (dd, J = 9.2, 3.8 Hz, 1H), 3.28 (dd,
J = 16.9, 9.2 Hz, 1H), 2.56 (dd, J = 16.9, 3.8 Hz, 1H); MS m/z: 273.7 (M