JOURNAL OF THE CHINESE
CHEMICAL SOCIETY
Synthetic Route to Indazoles and Pyrazoles
3 H). 13C-NMR (100 MHz, DMSO-d6): 149.47, 143.73, 140.21,
130.79, 128.9, 128.68, 128.47, 127.14, 127.07, 125.17, 107.86,
13.67. 1-(2,4-Dinitrophenyl)-5-methyl-3-phenyl-1H-pyrazole
(11c): IR: 3120, 2990, 1650, 1610, 1510vs, 1390. 1H-NMR (400
MHz, DMSO-d6): 9.68 (d, J = 2, 1 H); 8.33 (d, J = 8.4, 1 H); 7.43
(d, J = 8.4, 1 H); 7.35-7.22 (m, 5 H); 6.42 (s, 1 H); 2.36 (s, 3 H).
13C-NMR (100 MHz, DMSO-d6): 152.69. 145.73, 145.29,
145.00, 139.2, 129.69, 129.56, 129.23, 127.00, 120.85, 109.43.
3,5-Diphenyl-1H-pyrazole (12a): IR (KBr): 3300, 3100, 2920,
1490. 1H-NMR (400 MHz, DMSO-d6): 7.20 (s, 1 H); 7.51-7.31
(m, 5 H); 7.90, 7.83 (two d, J = 7.2, 5 H,); 13.41 (s, 1 H).
13C-NMR (100 MHz, DMSO-d6): 152.30, 146.03, 145.37,
137.18, 136.28, 128.77, 128.29, 121.52, 117.08. 3-Methyl-1-
phenyl-1,4,5,6-tetrahydrocyclopenta[c]pyrazole (13b): IR
(KBr): 3114, 2987, 1649, 1598, 1463, 1221. 1H-NMR (400 MHz,
DMSO-d6): 7.14-7.61 (m, 5 H); 2.98 (m, 2 H); 2.56 (s, 4 H); 2.15
(s, 3 H). 13C-NMR (100 MHz, DMSO-d6): 148.98, 143.44,
140.46, 129.34, 128.35, 122.37, 118.37, 30.97, 26.70, 22.19,
13.01. 1-(2,4-Dinitrophenyl)-3-methyl-1,4,5,6-tetrahydrocy-
clopenta [c]pyrazole (13c): IR (KBr): 3055, 2990, 1610, 1510,
1370. 1H-NMR (400 MHz, DMSO-d6): 8.95 (s, J = 2.4, 1 H); 8.66
(dd, J = 8.2, 2.4, 1 H); 7.75 (d, J = 8.4, 1 H); 2.80 (m, 2 H); 2.62 (s,
4 H); 2.21 (s, 3 H). 13C-NMR (100 MHz, DMSO-d6): 152.30,
146.03, 145.37, 137.28, 126.28, 128.77, 128.28, 121.52, 117.08,
32.15, 23.19, 20.34, 12.40. 1-(2,4-Dinitrophenyl)-3-methyl-
4,5,6,7-tetrahydro-1H-indazole (14c): IR (KBr): 3060, 2980,
1600, 1510, 1380. 1H-NMR (400 MHz, DMSO-d6): 8.84 (d, J =
2.4, 1 H); 8.57 (dd, J = 8.8, 2.4, 1 H); 7.99 (d, J = 8.8, 1 H); 2.48 (s,
3 H); 2.25 (s, 3 H); 1.72 (d, J = 4.4, 5 H). 13C-NMR (100 MHz,
DMSO-d6): 152.30, 146.03, 145.37, 137.28, 126.28, 128.77,
128.28, 121.52, 117.08, 33.35, 23.16, 23.09, 20.29, 10.41.
Proposed mechanism for the hedrazines
Scheme 3
condensation with b-dicaronyl compounds
using TSA (1)
Avance 2 model. Known products were characterized by compar-
ison of their spectra and physical data with those reported in the
literature.22-30
Preparation of Pyrazoles and Indazoles Using TSA (1):
A mixture of hydrazine 2 (1 mmol), b-dicarbonyl 3-8 (1 mmol)
and TSA(0.1 mmol) was stirred and heated at 80 °C in a preheated
oil bath for an appropriate time. After completion of the reaction
as indicated by TLC (AcOEt/n-hexane, 1:4), the reaction mixture
was dissolved in hot EtOH and catalyst was separated by filtra-
tion. The solvent was evaporated and the products 9-14 were puri-
fied by recrystallization in EtOH. The separated catalyst was
washed with diethyl ether, dried at 70 °C for 45 min, and reused in
another reaction.
Selected Spectral Data: 5-Methyl-1,3-diphenyl-1H-pyr-
azole (11b): IR (KBr): 3095, 2950, 1650, 1500, 1390. 1H-NMR
(400 MHz, DMSO-d6): 7.33-7.24 (m, 10 H); 6.35 (s, 1 H); 2.43 (s,
CONCLUSIONS
In summary, a new catalytic application of TSA as a
highly efficient and green solid acid catalyst to synthesize
indazoles and pyrazoles was presented. Simple experimen-
tal procedure, utilization of a clean and recyclable catalyst,
the use of readily available starting materials, short period
of reactions and good to excellent yields make this method
a valid contribution to the existing methodologies.
ACKNOWLEDGEMENTS
The authors are thankful to Yasouj University Re-
search Council for the partial financial support.
REFERENCES
Fig. 1. Recyclability of TSA in the synthesis of 9a un-
1. Mangalagiu, I. I. Curr. Org. Chem. 2011, 15, 730.
der uptimized conditions.
J. Chin. Chem. Soc. 2014, 61, 000-000
© 2014 The Chemical Society Located in Taipei & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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