M. Tang, F.-M. Zhang / Tetrahedron 69 (2013) 1427e1433
1431
for 4f by using 1b (146 mg,1.0 mmol), TsNHNH2 (205 mg,1.1 mmol),
NaOH (104 mg, 2.6 mmol), and iodoethane (234 mg, 1.5 mmol) as
colorless oil. dH (400 MHz, CDCl3) 1.44 (3H, t, J 7.2 Hz), 3.81 (2H, s),
4.09 (2H, q, J 7.2 Hz), 7.12 (1H, s), 7.17e7.21 (3H, m), 7.24e7.30 (2H,
m), 7.33 (1H, s); dC (100 MHz, CDCl3) 15.5, 30.6, 46.8, 120.4, 126.0,
127.0, 128.37, 128.43, 138.7, 141.2; HRMS (ESI): MHþ, found:
187.1237. C12H15N2 requires 187.1230; nmax (liquid film) 3082, 3061,
procedure described for 4k by using 1c (146 mg, 1.0 mmol),
TsNHNH2 (205 mg, 1.1 mmol), NaOH (104 mg, 2.6 mmol), and allyl
bromide (180 mg, 1.5 mmol) as colorless oil. dH (400 MHz, CDCl3)
2.22 (3H, d, J 0.8 Hz), 4.71 (2H, dt, J 4.4, 1.2 Hz), 5.20e5.25 (2H, m),
5.99e6.09 (1H, m), 7.21 (1H, s), 7.27e7.31 (1H, m), 7.37e7.41 (2H,
m), 7.67e7.69 (2H, m); dC (100 MHz, CDCl3) 10.0, 54.5, 113.9, 118.3,
127.0, 127.4, 128.3, 129.4, 133.1, 134.1, 149.7; HRMS (ESI): MHþ,
found: 199.1232. C13H15N2 requires 199.1230; nmax (liquid film)
3026, 2981, 2934, 1494, 1449, 1397, 1356, 1157 cmꢂ1
.
3062, 3024, 2922, 2868, 1604, 1552, 1438, 1340, 1165 cmꢂ1
.
4.3.3. Preparation of 1-allyl-4-benzyl-1H-pyrazole (4i). Compound
4i (176 mg, 89%) was prepared following the procedure described for
4f by using 1b (146 mg, 1.0 mmol), TsNHNH2 (205 mg, 1.1 mmol),
NaOH (104 mg, 2.6 mmol), and allyl bromide (180 mg, 1.5 mmol) as
colorless oil. dH (400 MHz, CDCl3) 3.81 (2H, s), 4.66 (2H, dt, J 6.0,
1.2 Hz), 5.15e5.24 (2H, m), 5.94e6.04 (1H, m), 7.13 (1H, s), 7.17e7.20
(3H, m), 7.24e7.29 (2H, m), 7.35 (1H, s); dC (100 MHz, CDCl3) 30.6,
54.6,118.3,120.8,126.0,127.7,128.37,128.39,133.0,139.1,141.1; HRMS
(ESI): MHþ, found:199.1232. C13H15N2 requires 199.1230;nmax (liquid
4.5. Typical representative procedure for the synthesis
1-benzyl-3,5-diphenyl-1H-pyrazole (4n)
A mixture of chalcone (1d) (208 mg, 1.0 mmol) and TsNHNH2
(205 mg, 1.1 mmol) in EtOH (2 mL) were stirred at room temper-
ature for 48 h and then EtOH (2 mL), NaOH (44.0 mg, 1.1 mmol)
were added and the mixture was heated at reflux for 15 h, then the
solvent was removed under reduced pressure, then CH3CN (4 mL),
NaOH (60 mg, 1.5 mmol) and benzyl bromide (255 mg, 1.5 mmol)
were subsequently added and the mixture was stirred at room
temperature for 2 h. The product was extracted with Et2O and the
organic layer was washed with brine, dried over anhydrous MgSO4,
filtered, and concentrated in vacuo. Purification by chromatography
on silica gel afforded the desired product 4n as white crystalline
solid (276 mg, 89% yield). Mp 114e117 ꢁC; dH (400 MHz, CDCl3) 5.38
(2H, s), 6.66 (1H, s), 7.09 (2H, d, J 7.2 Hz), 7.21e7.30 (4H, m),
7.32e7.42 (7H, m), 7.87 (2H, d, J 7.2 Hz); dC (100 MHz, CDCl3) 53.2,
103.7, 125.6, 126.7, 127.4, 127.6, 128.55, 128.56, 128.6, 128.8, 130.6,
133.4, 137.7, 145.4, 150.9; HRMS (ESI): MHþ, found 311.1536.
C22H19N2 requires 311.1543, nmax (liquid film) 3060, 2955, 2924,
film) 3083, 3026, 2919, 2849, 1494, 1446, 1397, 1328, 1152 cmꢂ1
.
4.3.4. Preparation of 4-benzyl-1-(prop-2-yn-1-yl)-1H-pyrazole
(4j). Compound 4j (161 mg, 82%) was prepared following the
procedure described for 4f by using 1b (146 mg, 1.0 mmol),
TsNHNH2 (205 mg, 1.1 mmol), NaOH (104 mg, 2.6 mmol), and
propargyl bromide (177 mg, 1.5 mmol) as colorless oil. dH (400 MHz,
CDCl3) 2.45 (1H, t, J 2.4 Hz), 3.81 (2H, s), 4.85 (2H, d, J 2.4 Hz),
7.18e7.21 (3H, m), 7.24e7.30 (2H, m), 7.33e7.35 (2H, m); dC
(100 MHz, CDCl3) 30.5, 41.4, 74.4, 76.9, 121.3, 126.1, 127.5, 128.4,
139.8, 140.8; HRMS (ESI): MHþ, found: 197.1074. C13H13N2 requires
197.1073; nmax (liquid film) 3289, 3084, 3061, 3027, 2916, 2126,
1602, 1494, 1446, 1395, 1349, 1152 cmꢂ1
.
2853, 1452, 1361, 1307 cmꢂ1
.
4.4. Typical representative procedure for the synthesis
1-benzyl-4-methyl-3-phenyl-1H-pyrazole (4k)
4.5.1. Preparation of (3,5-diphenyl-1H-pyrazol-1-yl)(phenyl)meth-
anone (4o). Compound 4o (276 mg, 85%) was prepared following
the procedure described for 4n by using 1d (208 mg, 1.0 mmol),
TsNHNH2 (205 mg, 1.1 mmol), NaOH (104 mg, 2.6 mmol), and
benzoyl chloride (210 mg, 1.5 mmol) as colorless oil. dH (400 MHz,
CDCl3) 6.86 (1H, s), 7.35e7.44 (6H, m), 7.47e7.51 (4H, m), 7.59e7.63
(1H, m), 7.86 (2H, dd, J 8.0, 1.2 Hz), 8.11e8.13 (2H, m); dC (100 MHz,
CDCl3) 108.9, 126.3, 128.0, 128.2, 128.5, 128.7, 129.1, 130.8, 131.8,
131.9, 132.5, 133.1, 148.6, 153.5, 167.4; HRMS (ESI): MNaþ, found:
347.1158. C22H16N2ONa requires 347.1155; nmax (liquid film) 3061,
A mixture of (E)-2-methyl-3-phenylacrylaldehyde (1c) (146 mg,
1.0 mmol) and TsNHNH2 (205 mg, 1.1 mmol) in CH3CN (2 mL) were
stirred at room temperature for 3 h and then CH3CN (2 mL), NaOH
(44 mg, 1.1 mmol) were added and the mixture was heated at reflux
for 15 h, then NaOH (60 mg, 1.5 mmol) and benzyl bromide
(255 mg, 1.5 mmol) were subsequently added and the mixture was
stirred at room temperature for 2 h. The product was extracted with
Et2O and the organic layer was washed with brine, dried over an-
hydrous MgSO4, filtered, and concentrated in vacuo. Purification by
chromatography on silica gel afforded the desired product 4k as
colorless oil (233 mg, 94%). dH (400 MHz, CDCl3) 2.20 (3H, s), 5.27
(2H, s), 7.15 (1H, s), 7.21e7.35 (6H, m), 7.38e7.42 (2H, m), 7.69e7.71
(2H, m); dC (100 MHz, CDCl3) 10.1, 55.9, 114.2, 127.1, 127.4, 127.7,
127.9, 128.3, 128.7, 129.7, 134.1, 136.8, 149.7; HRMS (ESI): MHþ,
found 249.1380. C17H17N2 requires 249.1386, nmax (liquid film) 3061,
2924, 2856, 1709, 1560, 1488, 1453, 1331, 1305 cmꢂ1
.
4.5.2. Preparation of 1-ethyl-3,5-diphenyl-1H-pyrazole (4p). Comp-
ound 4p (243 mg, 98%) was prepared following the procedure de-
scribed for 4n by using 1d (208 mg, 1.0 mmol), TsNHNH2 (205 mg,
1.1 mmol), NaOH (104 mg, 2.6 mmol), and iodoethane (234 mg,
1.5 mmol) as colorless oil. dH (400 MHz, CDCl3) 1.44 (3H, t, J 7.2 Hz),
4.20 (2H, q, J 7.2 Hz), 6.57 (1H, s), 7.29 (1H, t, J 7.6 Hz), 7.38e7.48 (7H,
m), 7.84e7.86 (2H, m); dC (100 MHz, CDCl3) 15.9, 44.6, 103.3, 125.6,
127.5, 128.48, 128.54, 128.7, 128.8, 130.9, 133.6, 144.4, 150.5; HRMS
(ESI): MHþ, found: 249.1384. C17H17N2 requires 249.1386; nmax
3030, 2926, 2867, 1603, 1552, 1496, 1444, 1343, 1162 cmꢂ1
.
4.4.1. Preparation of (4-methyl-3-phenyl-1H-pyrazol-1-yl)(phenyl)
methanone (4l). Compound 4l (249 mg, 95%) was prepared fol-
lowing the procedure described for 4k by using 1c (146 mg,
1.0 mmol), TsNHNH2 (205 mg, 1.1 mmol), NaOH (104 mg,
2.6 mmol), and benzoyl chloride (210 mg, 1.5 mmol) as colorless oil.
dH (400 MHz, CDCl3) 2.31 (3H, s), 7.37e7.51 (5H, m), 7.58 (1H, t, J
7.2 Hz), 7.75 (2H, d, J 7.2 Hz), 8.21e8.25 (3H, m); dC (100 MHz, CDCl3)
10.4, 118.8, 127.8, 128.0, 128.5, 128.6, 130.0, 131.67, 131.72, 132.5,
132.7, 155.5, 165.9; HRMS (ESI): MNaþ, found: 285.0997.
C17H14N2ONa requires 285.0998; nmax (liquid film) 3061, 3030,
(liquid film) 3060, 2976, 2937,1605,1548,1481,1460,1373,1304 cmꢂ1
.
4.5.3. Preparation of 1-allyl-3,5-diphenyl-1H-pyrazole (4q). Compo-
und 4q (250 mg, 96%) was prepared following the procedure
described for 4n by using 1d (208 mg, 1.0 mmol), TsNHNH2
(205 mg, 1.1 mmol), NaOH (104 mg, 2.6 mmol), and allyl bromide
(180 mg, 1.5 mmol) as colorless oil. dH (400 MHz, CDCl3) 4.77 (2H,
dd, J 3.2, 1.6 Hz), 5.03 (1H, dd, J 16.8, 1.2 Hz), 5.20 (1H, dd, J 10.4,
1.2 Hz), 6.00e6.09 (1H, m), 6.61 (1H, s), 7.29 (1H, t, J 7.6 Hz),
7.37e7.46 (7H, m), 7.84e7.86 (2H, m); dC (100 MHz, CDCl3) 52.0,
103.3, 117.2, 125.6, 127.6, 128.52, 128.56, 128.59, 128.7, 130.6, 133.4,
133.8, 145.1, 150.9; HRMS (ESI): MHþ, found: 261.1385. C18H17N2
2925, 2867, 1603, 1552, 1495, 1447, 1343, 1162 cmꢂ1
.
4.4.2. Preparation
of
1-allyl-4-methyl-3-phenyl-1H-pyrazole
(4m). Compound 4m (155 mg, 78%) was prepared following the