1934
GORJIZADEH et al.
indicated by TLC, the reaction mixture was poured
into an aqueous sodium thiosulfate solution (1 M) and
extracted with diethyl ether (3 × 15 mL). The
combined organic layers were dried over MgSO4. The
solvent was concentrated in vacuo, the resulting product
was purified on silica gel using column chromate-
graphy (diethyl ether : n-hexane = 1 : 4) to afford the
pure compound.
ppm: 58.3, 130.5, 131.7, 135.1, 135.9, 141.0, 149.9, 161.5.
Found, %: C 38.51, H 2.21, N 8.64. C10H7IN2O2.
Calculated, %: C 38.24, H 2.25, N 8.92.
5-Carbaldehyde-4-iodo-1H-pyrazole (9). Yield 88%,
mp 134–1365°C. 13С NMR spectrum, δС, ppm: 57.3,
143.5, 154.0, 169.1. Found, %: C 21.46, H 1.33, N
12.58. C4H3IN2O. Calculated, %: C 21.64, H 1.37, N
12.61.
4-Iodo-1H-pyrazole (1). Yield 89%, mp 109–110°C.
13С NMR spectrum, δС, ppm: 57.6, 138.8. Found, %:
C 18.6, H 1.57, N 14.40. C3H3IN2. Calculated, %. C
18.57, H 1.56, N 14.43.
CONCLUSIONS
We have developed a facile process of synthesis of
iodopyrazole by the reaction of pyrazoles with iodine
using n-butyltriphenylphosphonium peroxodisulfate as
an oxidant at room temperature.
3,5-Bis(ethoxycarbonyl)-4-iodo-1H-pyrazole (2).
Yield 87%, mp 165–166°C. 13С NMR spectrum, δС,
ppm: 13.1, 59.3, 62.8, 142.5, 160.8. Found, %: C
31.89, H 3.25, N 8.27. C9H11IN2O4. Calculated, %. C
31.97, H 3.29, N 8.28.
ACKNOWLEDGMENTS
The authors gratefully acknowledge financial
support from the shoushtar Branch, Islamic Azad
University, Iran.
4-Iodo-1-phenylpyrazole (3). Light yellow oil,
yield 91%. 13С NMR spectrum, δС, ppm: 61.6, 123.9,
126.9, 128.9, 131.8, 138.2, 146.2 Found, %: C 39.91,
H 2.60, N 10.33. C9H7IN2. Calculated, %. C 40.02, H
2.62, N 10.37.
REFERENCES
1-(p-Chlorophenyl)-4-iodo-3-methyl-5-phenyl
pyrazole (4). Yield 88%, mp 138–139°C. 13С NMR
spectrum, δС, ppm: 14.1, 63.2, 115.9, 121.6, 123.9,
127.4, 128.4, 129.0, 131.8, 137.6, 143.9, 148.4. Found,
%: C 48.72, H 3.1, N 7.03. C16H12IN2Cl. Calculated,
%. C 48.69, H 3.07, N 7.09.
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13.5, 14.5, 55.4, 63.7, 145.2, 164.2. Found, %:
C
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28.48, H 3.51, N 11.05. C6H9IN2O. Calculated, %. C
28.59, H 3.60, N 11.11.
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3-(4-Amino phenyl)-4-iodo-1H-pyrazole (6). Yellow
oil, yield 90%. 13С NMR spectrum, δС, ppm: 58.2,
113.8, 125.6, 126.7, 140.3, 142.4, 148.8. Found, %: C
38.12, H 2.87, N 14.68. C9H8IN3. Calculated, %. C
37.92, H 2.83, N 14.73.
3-(4-Carboxy phenyl)-4-iodo-1H-pyrazole (8).
Yield 85%, mp 190–192°C. 13С NMR spectrum, δС,
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 86 No. 8 2016