8
H. Fan et al. / Tetrahedron xxx (2013) 1e9
Yield 71%, 245.8 mg; white solid; mp 176e177 ꢀC. 1H NMR
(300 MHz, CDCl3):
¼7.57 (d, J¼8.4 Hz, 2H), 7.25 (d, J¼8.1 Hz, 2H),
4.2.13. 4-(2,5-Dimethylphenyl)-1-(4-chlorophenyl)-3-(tri-
fluoromethyl)-1H-pyrazol-5-ol (3j).
d
7.08 (d, J¼8.4 Hz, 2H), 7.04 (s, 1H), 2.40 (s, 3H), 2.35 (s, 3H), 2.13 (s,
3H). 19F NMR (282 MHz, CDCl3):
d
2
¼ꢁ62.16 (s, 3F).13C NMR (100 MHz,
acetone-d6):
d¼149.9, 138.9 (q, JCeF¼35.0 Hz), 138.4, 138.0, 137.1,
136.1, 132.0, 130.5, 129.5, 126.2, 125.9, 122.4, 121.9 (q, 1JCeF¼267.6 Hz),
101.7 (m, 3JCeF), 20.2, 20.1, 19.2. IR (KBr) cmꢁ1: 2925, 1520, 1484, 1417,
1330,1182,1142,1128, 991, 821. MS: m/z (%)¼346 (Mþ, 100), 347 (23),
303 (30), 249 (13), 222 (12), 107 (10), 91 (40), 65 (11). HRMS (EI):
Calcd for C19H17F3N2O: 346.1293; found: 346.1297.
4.2.11. 4-(4-Methoxyphenyl)-1-(4-chlorophenyl)-3-(trifluoromethyl)-
1H-pyrazol-5-ol (3i).
Yield 69%, 252.6 mg; white solid; mp 146e147 ꢀC. 1H NMR
(300 MHz, acetone-d6):
d
¼7.93 (d, J¼8.7 Hz, 2H),
d
¼7.59 (d,
J¼9.0 Hz, 2H), 7.09-7.18 (m, 2H), 7.05 (s, 1H), 2.30 (s, 3H), 2.16 (s,
3H). 19F NMR (acetone-d6, 282 MHz):
(100 MHz, acetone-d6):
d
¼ꢁ62.66 (s, 3F). 13C NMR
2
d
¼150.1, 139.5 (q, JCeF¼35.0 Hz), 137.3,
135.5, 134.8, 132.5, 132.2, 129.8, 129.3, 129.1, 128.4, 123.7, 121.7 (q,
1JCeF¼267.6 Hz), 102.2 (m, JCeF), 20.0, 18.8. IR (KBr) cmꢁ1: 2927,
3
1597, 1533, 1486, 1416, 1330, 1207, 1132, 1004, 833, 808. MS: m/z
(%)¼366 (Mþ, 85), 323 (48), 111 (100), 75 (56), 57 (68), 56 (44), 43
(87), 41 (67). HRMS (EI): Calcd for C18H14ClF3N2O: 366.0747; found:
366.0750.
4.2.14. 4-(2,4-Dimethylphenyl)-1-(4-chlorophenyl)-3-(tri-
Yield 71%, 261.3 mg; white solid; mp 144e145 ꢀC. 1H NMR
fluoromethyl)-1H-pyrazol-5-ol (3k).
(300 MHz, acetone-d6):
d
¼7.90 (d, J¼9.0 Hz, 2H),
d
¼7.59 (d,
J¼9.0 Hz, 2H), 7.32 (d, J¼8.4 Hz, 2H), 6.99 (d, J¼8.7 Hz, 2H), 3.84 (s,
3H). 19F NMR (282 MHz, acetone-d6):
d
¼ꢁ62.63 (s, 3F). 13C NMR
2
(100 MHz, acetone-d6):
d
¼159.5, 150.1, 139.2 (q, JCeF¼35.8 Hz),
137.1, 132.4, 131.5, 129.1, 124.0, 121.8 (q, 1JCeF¼267.6 Hz), 121.4, 113.9,
3
103.4 (m, JCeF), 54.7. IR (KBr) cmꢁ1: 2967, 2839, 1526, 1498, 1480,
1340, 1252, 1182, 1129, 984, 838. MS: m/z (%)¼368 (Mþ, 100), 370
(32), 369 (20), 200 (28), 113 (23), 111 (67), 77 (30), 75 (32). HRMS
(EI): Calcd for C17H12ClF3N2O2: 368.0539; found: 368.0541.
4.2.12. 4-(2-Methoxyphenyl)-1-(4-chlorophenyl)-3-(trifluoromethyl)-
1H-pyrazol-5-ol (3i0).
Yield 63%, 230.6 mg; white solid; mp 181e182 ꢀC. 1H NMR
(300 MHz, acetone-d6):
d
¼7.93 (d, J¼9.0 Hz, 2H),
d
¼7.59 (d,
J¼8.7 Hz, 2H), 7.02e7.12 (m, 3H), 2.33 (s, 3H), 2.16 (s, 3H). 19F NMR
(acetone-d6, 282 MHz):
d
¼ꢁ62.68 (s, 3F). 13C NMR (100 MHz, ace-
tone-d6):
d
¼150.2,139.6 (q, 2JCeF¼35.8 Hz),138.5,138.1,137.3, 132.2,
131.9, 130.5, 129.1, 126.3, 125.7, 125.5, 123.7, 121.7 (q,
1JCeF¼267.6 Hz), 101.9 (m, JCeF), 20.2, 19.1. IR (KBr) cmꢁ1: 2924,
3
1594, 1482, 1413, 1331, 1180, 1130, 991, 833, 808. MS: m/z (%)¼366
(Mþ, 100), 368 (32), 323 (41), 127 (28), 115 (28), 111 (85), 77 (32), 43
(35). HRMS (EI): Calcd for
366.0746.
C18H14ClF3N2O: 366.0747; found:
4.3. General procedure for the synthesis of compounds 4
Yield 7%, 25.8 mg; white solid; mp 183e184 ꢀC. 1H NMR
(300 MHz, acetone-d6):
d
¼7.92 (d, J¼9.0 Hz, 2H), 758 (d, J¼9.3 Hz,
3-Trifluoromethyl-4-diazopyrazolinones 1a (254 mg, 1 mmol)
and Lawesson reagent (404 mg, 1 mmol) were dissolved in xylene
(10 mL). The reaction mixture was stirred at reflux for about 5 h,
until the starting material of 1 disappeared while monitoring by
TLC. The solvent was removed in vacuum and the residue was
purified on silica gel using petroleum ether/ethyl acetate (10:1) as
eluent to afford the corresponding product 4.
2H), 7.28e7.41 (m, 2H), 7.06 (d, J¼9.3 Hz, 1H), 7.00 (d, J¼7.2 Hz, 1H),
3.82 (s, 3H). 19F NMR (282 MHz, acetone-d6):
d
¼ꢁ62.34 (s, 3F). IR
(KBr) cmꢁ1: 3007, 2948,1591,1486,1414,1276,1170,1131,1096, 986,
833, 756. MS: m/z (%)¼368 (Mþ, 58), 113 (31), 111 (100), 75 (37), 57
(25), 56 (30), 43 (41), 41 (36). HRMS (EI): Calcd for C17H12ClF3N2O2:
368.0539; found: 368.0537.