A mild procedure for the preparation of o-nitrophenols by nitro urea or ammonium nitrate in the presence of silica sulfuric acid (SiO 2-OSO3H)

Article abstract of DOI:10.1002/cjoc.201190148

A mixture of ammonium nitrate or nitro urea and silica sulfuric acid was found to be efficient and environmentally friendly nitrating media for the preparation of orto-nitro phenols in dichloromethane at room temperature. A mixture of ammonium nitrate or nitro urea and silica sulfuric acid was found to be efficient and environmentally friendly nitrating media for the preparation of orto-nitro phenols in dichloromethane at room temperature.

Full text of DOI:10.1002/cjoc.201190148

FULL PAPER
A Mild Procedure for the Preparation of o-Nitrophenols by Nitro
Urea or Ammonium Nitrate in the Presence of Silica Sulfuric
Acid (SiO2-OSO3H)
Ghorbani-Choghamarani, Arash*
Goudarziafshar, Hamid
Nikoorazm, Mohsen
Zamani, Parisa
Naserifar, Zahra
Department of Chemistry, Faculty of Science, Ilam University, P.O. Box 69315516 Ilam, Iran
A mixture of ammonium nitrate or nitro urea and silica sulfuric acid was found to be efficient and environmen-
tally friendly nitrating media for the preparation of orto-nitro phenols in dichloromethane at room temperature.
Keywords nitration, phenol, nitro urea, ammonium nitrate, silica sulfuric acid
Introduction
fertilizer industry and as an explosive in mining opera-
tions. Ammonium nitrate has been also applied as re-
agent in different chemical reactions.22-25 Nitro urea was
prepared via our newly reported procedure.26
Consequently, herein we decided to report a metal-
free, green and heterogeneous procedure for the nitra-
tion of substituted phenolic compounds by ammonium
nitrate and/or nitro urea and silica sulfuric acid under
mild and heterogeneous conditions (Scheme 1).
Nitration of aromatic compounds is one of the most
fundamental and useful reactions for introducing the
nitrogen atom directly into aromatic rings.1 Nitration of
aromatic compounds is an industrially important reac-
tion as the nitrated products are intermediates for fine
chemicals and pharmaceuticals.2 The nitration of phe-
nols is a fundamental unit process of great industrial
importance generating commercially valuable interme-
diates and there is a great need for regio-selective pollu-
tion free processes.3 Usually, nitrations of phenols are
not region-selective and are the cause of environmental
concerns regarding the disposal of large excesses of con-
centrated nitric acid and non-environmentally friendly
metallic catalysts or reagents [such as WO3HNO3,4 TiO2-
Scheme 1
[Ti4H11(PO4)9]•nH2O/HNO3,5
Yb-Mo-HKSF-HNO3,6
ZnCl2/HNO3,7 TBAB/HNO3,8 Bi5O(OH)9(NO3)4/SOCl2,9
(NH4)2SO4•NiSO4•6H2O/HNO3,10
([bmim][HSO4])/
NaNO3,11 montmorillonite KSF/HNO3,12 silica sulfuric
(a) X = Y = H; (b) X = Cl, Y = H; (c) X = F, Y = H; (d) X = OMe, Y = H;
(e) X = Br, Y = H; (f) X = OCH2Ph, Y = H; (g) X = Y = Cl; (h) X = CH3,
Y = Ome; (i) X = CH3, Y = H; (j) X = Ph, Y = H; (k) X = (CH3)3C, Y =
H; (l) X = (CH3)2CH, Y = H; (m) X = OPh, Y = H; (n) X = Me, Y =
(CH3)3C
13
acid/NaNO3
and Hf or Zr oxychloride com-
plex-KSF/HNO314] in these processes. Therefore, de-
signing systems, which reduce the mentioned problems,
is of great interest.
Results and discussion
Result of the nitration reactions including molar ratio
of reagents, time and yields of nitarated phenols are
summarized in Table 1.
All of the o-nitrophenos were easily obtained via
mixing the corresponding phenols with ammonium ni-
trate (NH4NO3) or nitro urea (NH2CONHNO2) and silica
sulfuric acid (SiO2-OSO3H) in dichloromethane and stir-
ring the resulting mixture at room temperature. After re-
action completion, resulting yellow to orange pasty mix-
ture was passed through the column chromatography.
Recently we have examined a variety of heteroge-
neous systems, generating nitronioum ion (NO+2 )
which was used for different organic reactions.15-21 In
this light, we decided to disclose a new procedure for
the nitration of substituted phenols by a mixture con-
taining ammonium nitrate or nitro urea and silica sulfu-
ric acid.
Ammonium nitrate is a cost, effective, nontoxic and
environmentally friendly chemical, which is used in
*
E-mail: arashghch58@yahoo.com or a.ghorbani@mail.ilam.ac.ir; Tel./Fax: 0098-0841-2227022
Received August 9, 2010; revised October 19, 2010; accepted December 21, 2010.
Chin. J. Chem. 2011, 29, 731— 734
© 2011 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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Ghorbani-Choghamarani et al.
FULL PAPER
Table 1 o-Nitration of substituted phenols using ammonium nitrate I or nitro urea II and silica sulfuric acid III in dichloromethane at
room temperature
Entry Substrate Product
Ammonium nitrate/mmol
Nitro urea/g
silica sulfuric acid/g
Time/min
160
190
75
Yielda/%
30
47
72
76
86
96
69
71
88
50
75
55
69
58
47
50
50
52
43
63
51
70
63
77
87
70
67
65
1
1a
1a
1b
1b
1c
1c
1d
1d
1e
1e
1f
2a
2a
2b
2b
2c
2c
2d
2d
2e
2e
2f
3
—
—
0.8
0.4
0.4
0.5
0.2
0.5
0.3
0.4
0.4
0.5
0.2
0.4
0.2
0.4
0.2
0.4
0.4
0.4
0.4
0.4
0.2
0.4
0.2
0.4
0.4
0.4
0.4
0.5
2
0.48
3
2
—
—
4
0.48
120
75
5
2
—
—
6
0.48
140
35
7
2
—
—
8
0.48
180
55
9
2
—
—
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
0.48
75
2
—
—
25
1f
2f
0.48
70
1g
1g
1h
1h
1i
2g
2g
2h
2h
2i
2
—
—
115
195
20
0.48
2
—
—
0.48
15
2
—
—
80
1i
2i
0.48
120
55
1j
2j
2
—
—
1j
2j
0.48
110
15
1k
1k
1l
2k
2k
2l
2
—
—
0.48
10
2
—
—
10
1l
2l
0.48
230
80
1m
1m
1n
1n
2m
2m
2n
2n
2
—
—
0.48
—
50
2
—
25
0.48
95
a Yields after purification by column chromatography.
This procedure in comparison with previously re-
ported is a metal-free method with mild content. Also
herein a wide variety of ortho nitro phenols has been
prepared.
Plausible mechanism for the nitration of phenols by
described system is outlined in Scheme 2.
To show the efficiency of the described system in
comparison with previously reported procedures in the
literature, we compared our obtained results for the ni-
tration of 4-fluorophenol (as a typical example) with the
best of the well-known data from the literature as shown
in the Table 2.
1H NMR, and 13C NMR) and physical data with those of
authentic samples.
Nitration of 4-bromophenol using nitro urea and sil-
ica sulfuric acid
A 10 mL round-bottom flask was charged with
4-bromophenol (0.173 g, 1 mmol), silica sulfuric acid
(0.5 g), nitro urea (0.48 g) and dichloromethane (5 mL).
This mixture was stirred at room temperature for 75 min
(the progress of the reaction was monitored by TLC).
After reaction completion, crud product was passed
through the column chromatography (packed by silica
gel) using CH2Cl2 as eluent. Solvent was removed by
simple distillation and pure 4-bromo-6-nitro-phenol ob-
tained in 50% yield (0.109 g) as crystalline pale yellow
solid; m.p. 79—81 ℃; 1H NMR (CDCl3, 400 MHz) δ:
10.51 (s, 1H), 8.27 (d, J＝2.4 Hz, 1H), 7.69 (dd, J＝6.8,
2.4 Hz, 1H), 7.10 (d, J＝8.8 Hz, 1H); 13C NMR (CDCl3,
100 MHz) δ: 154.1, 140.4, 134.0, 127.3, 121.7, 111.7.
Experimental
General
Chemicals were purchased from Fluka, Merck and
Aldrich chemical companies. The nitration products
were characterized by comparison of their spectral (IR,
732
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© 2011 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Chin. J. Chem. 2011, 29, 731— 734

A Mild Procedure for the Preparation of o-Nitrophenols
Scheme 2
Table 2 Comparison of the different methods used for the nitration of 4-fluorophenol
Entry
Reagent and conditions
NH4NO3/SiO2OSO3H
Time/min
75
Yielda/%
Reference
1
86
This work
2
NH2CONHNO2/SiO2OSO3H
Mn(OAc)2/YbMo-HKSF
[bmim][HSO4])/NaNO3
Zr oxychloride complex-KSF/HNO3
TBAB/ HNO3
140
12 h
30
96
This work
3
86
6
4
80
11
14
8
5
16 h
6 h
85
6
97
7
Silica chloride/NaNO2
Bi(NO3)3/KSF
30
67
27
28
8
16
82
a Isolated yield.
Conclusion
Org. Process Res. Dev. 2003, 7, 95.
Muathen, H. A. Molecules 2003, 8, 593.
9
In summary we have demonstrated that a mixture of
ammonium nitrate or nitro urea and silica sulfuric acid
act as mild and heterogeneous media for the ortho-
nitration of substituted phenols. This was a convenient
and environmentally friendly route to prepare substi-
tuted ortho-nitrophenols in high purity and reasonable
yields.
10 Tasneem, Ali, M. M.; Rajanna, K. C.; Saiparakash, P. K.
Synth. Commun. 2001, 31, 1123.
11 Tajik, H.; Niknam, K.; Parsa, F. J. Iran Chem. Soc. 2009, 6,
159.
12 Yin, W. P.; Shi, M. Tetrahedron 2005, 61, 10861.
13 Zolfigol, M. A.; Mirjalili, B. F.; Bamoniri, A.; Karimi Zar-
chi, M. A.; Zarei, A.; Khazdooz, L.; Noei, J. Bull. Korean
Chem. Soc. 2004, 25, 1414.
14 Shi, M.; Cui, S. C.; Yin, W. P. Eur. J. Org. Chem. 2005,
2379.
Acknowledgment
Financial support for this work by the Ilam Univer-
sity, Ilam, Iran is gratefully acknowledged.
15 Ghorbani-Choghamarani, A.; Rezaei, S. J. Chin. Chem. Soc.
2009, 56, 251.
16 Ghorbani-Choghamarani, A.; Goudarziafshar, H.; Nikoorazm,
M.; Yousefi, S. Can. J. Chem. 2009, 87, 1144.
17 Ghorbani-Choghamarani, A.; Hajjami, M.; Goudarziafshar,
H.; Nikoorazm, M.; Mallakpour, S.; Sadeghizadeh, F.;
Azadi, G. Monatsh. Chem. 2009, 140, 607.
References
1
2
3
4
5
Kawada, A.; Takeda, S.; Yamashita, K.; Abe, H.; Harayama,
T. Chem. Pharm. Bull. 2002, 50, 1060.
Anuradha, V.; Srinivas, P. V.; Aparna, P.; Rao, J. M. Tetra-
hedron Lett. 2006, 47, 4933.
Rajagopal, R.; Srinivasan, K. V. Synth. Commun. 2003, 33,
961.
Khder, A. S.; Ahmed, A. I. Appl. Catal. A: Gen. 2009, 354,
153.
18 Ghorbani-Choghamarani, A.; Zolfigol, M. A.; Rastegar, T.
Chin. J. Catal. 2009, 30, 273.
19 Goudarziafshar, H.; Ghorbani-Choghamarani, A.; Nikoorazm,
M.; Naserifar, Z. Chin. J. Chem. 2009, 27, 1801.
20 Ghorbani-Choghamarani, A.; Nikoorazm, M.; Goudarziaf-
shar, H.; Tahmasbi, B. Bull. Korean Chem. Soc. 2009, 30,
1388.
Bharadwaj, S. K.; Hussain, S.; Kar, M.; Chaudhuri, M. K.
Appl. Catal. A: Gen. 2008, 353, 62.
21 Ghorbani-Choghamarani, A.; Nikoorazm, M.; Goudarziaf-
shar, H.; Shiri, L.; Chenani, Z. Bull. Korean Chem. Soc.
2009, 30, 972.
6
7
Yin, W. P.; Shi, M. Arkivoc 2009, 6.
Kamal, A.; Kumar, B. A.; Arifuddin, M.; Patrick, M. Ultra-
son. Sonochem. 2004, 11, 455.
22 Meshram, H. M.; Ganesh, Y. S. S.; Madhavi, A. V.; Esh-
8
Joshi, A. V.; Baidoosi, M.; Mukhopadhyay, S.; Sasson, Y.
Chin. J. Chem. 2011, 29, 731— 734
© 2011 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.cjc.wiley-vch.de
733

Ghorbani-Choghamarani et al.
FULL PAPER
waraiah, B.; Yadav, J. S.; Gunasekar, D. Synth. Commun.
2003, 33, 2497.
23 Ghorbani-Choghamarani, A.; Zolfigol, M. A.; Rastegar, T.
Chin. J. Catal. 2009, 30, 273.
hedron 2000, 56, 6683.
26 Ghorbani-Choghamarani, A.; Zolfigol, M. A.; Hajjami, M.;
Rastgoo, S.; Mallakpour, S. Lett. Org. Chem. 2010, 7 (in
press).
24 Yadav, J. S.; Meshram, H. M.; Reddy, G. S.; Sumithra, G.
Tetrahedron Lett. 1998, 39, 3043.
25 Doxsee, K. M.; Franicis, P. E. J.; Weakley, T. J. R. Tetra-
27 Zolfigol, M. A.; Shirini, F.; Ghorbani-Chogamarani, A.
Phosphorus, Sulfur, Silicon, Relat. Elem. 2003, 178, 2019.
28 Shi, M.; Cui, S. C. Adv. Synth. Catal. 2003, 345, 1197.
(E1008098 Zhao, C.; Zheng, G.)
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Chin. J. Chem. 2011, 29, 731— 734