Design of ionic liquid 3-methyl-1-sulfonic acid imidazolium nitrate as reagent for the nitration of aromatic compounds by in situ generation of NO 2 in acidic media

Article abstract of DOI:10.1021/jo300137w

3-Methyl-1-sulfonic acid imidazolium nitrate ([Msim]NO₃) as a new Bronsted acidic ionic liquid and nitrating agent was prepared and used for the efficient nitration of aromatic compounds (even aniline derivatives). The dramatic effect of this reagent by in situ generation of nitrogen dioxide as a radical on aromatic compounds to give nitroarenes has been studied.

Full text of DOI:10.1021/jo300137w

Note
pubs.acs.org/joc
Design of Ionic Liquid 3-Methyl-1-sulfonic Acid Imidazolium Nitrate
as Reagent for the Nitration of Aromatic Compounds by in Situ
Generation of NO in Acidic Media
2
,†
,†
†
‡
Mohammad A. Zolfigol,* Ardeshir Khazaei,* Ahmad R. Moosavi-Zare, Abdolkarim Zare,
§
†
†
†
Hendrik G. Kruger, Zhila Asgari, Vahid Khakyzadeh, and Masoud Kazem-Rostami
†
Faculty of Chemistry, Bu-Ali Sina University, Hamedan 6517838683, Iran
‡
Department of Chemistry, Payame Noor University, PO Box 19395-4697, Tehran, Iran
§
School of Chemistry, University of KwaZulu-Natal, Durban 4001, South Africa
*
S Supporting Information
ABSTRACT: 3-Methyl-1-sulfonic acid imidazolium nitrate ([Msim]-
NO ) as a new Brønsted acidic ionic liquid and nitrating agent was
3
prepared and used for the efficient nitration of aromatic compounds
(
even aniline derivatives). The dramatic effect of this reagent by in situ
generation of nitrogen dioxide as a radical on aromatic compounds to give
nitroarenes has been studied.
2
c
compounds, such as sodium nitrite/[Msim]Cl, trichloroiso-
onic liquids (ILs) have received considerable interest as eco-
friendly solvents, catalysts, and reagents in the context of
4b,c
cyanuric acid or silica sulfuric acid/NaNO /wet SiO ,
I
2
2
4
d
4e
trimethylsilyl nitrate, N-nitropyridinium salts, nitrogen
oxide, nitric acid/P O /silica gel, nitric acid/mixed metal
green synthesis because of their unique properties such as low
volatility, nonflammability, high thermal stability, negligible
vapor pressure, and ability to dissolve a wide range of
4
f
4g
2
5
4
h
4i
oxides, nitric acid/lanthanide reagents, HNO
−Ac
3
O system
][BF ] in
/air-
2
1
4j
4k
materials. In continuation of a project involving the
in [bmpy][N(Tf)
[emim][X] (X = OTf , CF
2
], HNO
3
in [bmim]Otf, [NO
2
4
−
−
−
4l
production and applications of acidic ILs in organic synthesis,
we have recently introduced a new category of ionic liquids,
3
COO , and NO
3
), NO
2
4m
catalyzed by sulfonic acid functionalized ionic liquid, and a
mixture of nitric acid and acetic anhydride in ionic liquid.
4n
namely, sulfonic acid functionalized imidazolium salts
2
(
SAFIS). These ILs were successfully employed as catalysts
There are rare nitrating agents in which both an acidic catalyst
and a nitro group source are present and are simultaneously
employed. Moreover, many of the reported methods are
associated with one or more of the following drawbacks: (i) low
yields, (ii) long reaction times, (iii) the use of a large catalyst
load, (iv) the use of toxic or expensive catalysts, (v) low
regioselectivity, (vi) over nitration, (vii) oxidation of reagents,
and (viii) safety problems. Thus, the design of an efficient,
inexpensive, nonpolluting, and versatile reagent for the nitration
aromatic compounds is still of practical importance.
2
a
2b
to prepare bis(indolyl)methans, N-sulfonyl imines, nitro
2c
2d
phenolic compounds, 1-amidoalkyl-2-naphthols, and benzi-
midazoles. Herein, we report the novel ionic liquid 3-methyl-
-sulfonic acid imidazolium nitrate ([Msim]NO ), which
2
e
1
3
exhibits many interesting properties (Figure 1).
Recently, we have employed a mixture of 3-methyl-1-sulfonic
acid imidazolium chloride (as a co-catalyst) and sodium nitrite
2
c
(
as nitrating agent) for the nitration of phenolic compounds.
+
−
This combination was similar to N O (N O ⇔ NO NO ) in
the case of generation of HNO and NO , which worked as a
nitrosating agent. For that system, a nitrous acid catalyzed
2
4
2
4
3
Figure 1. Structure and color of 3-methyl-1-sulfonic acid imidazolium
nitrate.
+
2
2c
2
c,4b,c
mechanism can be proposed.
Moreover, using 3-methyl-1-
The nitration of arenes is an interesting process, not only for
the application of nitroarenes as explosives but also due the
versatile use of nitroarenes as intermediates in various
sulfonic acid imidazolium chloride/sodium nitrate, only
phenolic compounds were nitrated, and the system did not
work for the nitration of the other aromatic compounds.
3
important functional group transformations. Nitro-aromatic
However, in the present investigation, [Msim]NO by the in
3
compounds are also extensively utilized as chemical feedstocks
for a wide range of useful materials such as dyes,
pharmaceuticals, perfumes, and plastics. Several reagents
and catalysts have been employed for the nitration of aromatic
situ generation of NO as a radical without any co-catalysts was
2
4a
Received: January 22, 2012
Published: March 13, 2012
©
2012 American Chemical Society
3640
dx.doi.org/10.1021/jo300137w | J. Org. Chem. 2012, 77, 3640−3645

The Journal of Organic Chemistry
Note
1
used to produce a wide range of aromatic compounds in high
yields and very short reaction times. Direct nitration of aniline
at room temperature is another highlight in this method.
With these issues in mind, we designed and synthesized the
ionic liquid 3-methyl-1-sulfonic acid imidazolium nitrate
The H NMR spectrum of the ionic liquid that remained in
the test tube after all the NO and O was driven off was
2
2
determined. This spectrum showed the existence of the 1-
methylimidazolium cation. It is also clear that [Msim]NO even
at room temperature led to the formation of NO , O , H O,
3
2
2
2
(
[Msim]NO ) as a new SAFIS, a highly efficient and organic
and the zwitterionic salt. The latter is hydrolyzed by H O to
3
2
reagent without the need of a co-catalyst for the nitration of
various aromatic compoundes (Scheme 1).
give 1-methylimidazolium cation and hydrogen sulfate anion
(Scheme 4), which was observed by NMR. The cation is then
converted to the initial starting material (1-methylimidazole)
upon neutralization with base, followed by regeneration of
Scheme 1. Nitration of Aromatic Compounds Using
[
Msim]NO3
[Msim]NO via [Msim]Cl (Scheme 8).
3
To confirm that [Msim]Cl was completely converted to
[
Msim]NO , a solution of AgNO in distilled water was added
3
3
to a solution of the reagent in distilled water. The absence of
AgCl precipitate indicates complete conversion of the [Msim]
After the preparation of [Msim]NO via the reaction of
3
Cl to [Msim]NO . Excess chlorosulfonic acid is removed
3
[
Msim]Cl with nitric acid (Scheme 2), its structure was
through repeated washing of the IL with dichloromethane.
1
13
identified by IR, H and C NMR, mass spectra, and CHN
analysis.
Slight excess of HNO did not influence the performance of the
3
IL as a nitration agent.
The IR spectrum of the reagent shows two strong peaks at
We have also investigated the potential of [Msim]NO as a
3
−
1
ca. 1354 and 1635 cm that are typical of ν
symmetric
nitration agent on a model reaction with naphthalene. NO2
O−NO
stretching vibration and ν
asymmetric stretching
exists in equilibrium with dinitrogen tetroxide (N O ).
O−NO
2 4
vibration, respectively. Additionally, the two peaks observed
Homolytic dissociation of dinitrogen tetroxide to form the
−1
+
−
at 1166 and 1309 cm correspond to vibrational modes of the
NO radical and heterolytic dissociation produces NO , NO ,
2
3
1
−
+
3
N−SO bond. The H NMR spectrum of [Msim]NO shows
the unmistaken acidic hydrogen (SO H) peak at 14.24 ppm. To
NO , and NO . Therefore in this case, several intermediates
2 2
2
3
3
of nitrogen oxides could be found. We investigated the effective
confirm that this peak is really related to the hydrogen of SO H
application of NO with iodine as a radical scavenger (Scheme
3
2
1
7
in the compound, we also acquired the H NMR spectra of
5). In the presence of iodine; the yield of 1-nitro naphthalene
ClSO H, [Msim]Cl and 1-methylimidazolium chloride with
was very low even after 24 h. Nitration of naphthalene was also
examined in the presence of butylated hydroxytoluene (BHT)
as a radical scavenger. In this reaction media, the nitration
process was carried out slowly, and the yield of 1-nitro-
naphthalene was decreased even after long reaction time. It can
therefore be concluded that nitrogen dioxide in the radical form
makes up the bulk of the active species under these reaction
conditions. The results are presented in Table 1.
3
HNO in DMSO-d . In these spectra, the peaks of the acidic
3
6
hydrogens of [Msim]NO , ClSO H, [Msim]Cl, and 1-
3
3
methylimidazolium chloride with HNO were observed at
3
1
4.24, 13.45, 13.96, 8.46, and 13.01 ppm, respectively. The rest
of the NMR signals are provided in the Experimental Section.
The mass spectrum of the compound gave the correct
molecular ion peak at 225.
The thermogram (TG) of the reagent shows several weight
losses. The loss of about 21% of weight from 60 to 160 °C
When our reagent was reacted with benzenethiol, the main
product was 1,2-diphenyldisulfane. As shown in Scheme 6
•
appears to correspond to the loss of NO . The second weight
benzenethiol is converted to the corresponded Ar-S radical in
2
4a
loss occurs between 240 and 320 °C and the subsequent loss
after 320 °C are related to molecular decomposition (Figure 2).
An experiment was performed to confirm the loss of nitrogen
dioxide from [Msim]NO3 (Figure 3). The gas (nitrogen
dioxide) that was released from the reagent upon heating at
about 60 °C was collected over a test tube and transferred to a
round-bottomed flask in the presence of copper powder and
the presence of NO2. Two of these radicals dimerize to form
1,2-diphenyldisulfane, and nitrous acid is a byproduct in this
reaction (Scheme 6).
A plausible mechanism for the nitration of naphthalene
involves the release of NO from [Msim]NO to produce the
2
3
naphthalene radical and nitrous acid (HNO ). A second NO
2
2
radical and the naphthalene radical react to form nitro
naphthalene (Scheme 7).
In contrast to many previously reported procedures for the
nitration of aniline, we have successfully nitrated aniline to
ethyl acetate. NO in equilibrium with dinitrogen tetroxide
2
5
(
N O ) reacts with copper metal to form Cu(NO ) at room
2
4
3 2
temperature in 45 min. In this reaction, appearance of the blue
color due to copper nitrate formation in anhydrous media i6s
convincing evidence of the release of nitrogen dioxide.
Moreover, the excess copper powder residue turned black
over time, suggesting that O is produced from [Msim]NO as
produce 2-nitroaniline and 4-nitroaniline using [Msim]NO . In
3
+
the existing methods, the nitrogen of aniline attracts H in
acidic media, thus deactivating the nitration process. The
8
reaction proceeds via an ionic mechanism, and the resulting
2
3
well. Oxygen reacts with copper metal to form the black copper
oxide as an insoluble residue (Scheme 3 and Figure 3).
product (3-nitroaniline) forms in low yield. In our method with
[Msim]NO , the in situ generation of NO2 via a radical
3
Scheme 2. Preparation of 3-Methyl-1-sulfonic Acid Imidazolium Nitrate, [Msim]NO3
3
641
dx.doi.org/10.1021/jo300137w | J. Org. Chem. 2012, 77, 3640−3645

The Journal of Organic Chemistry
Note
Figure 2. Thermal gravimetry (TG) and differential thermal gravimetry (DTG) of [Msim]NO3.
Table 1. Effect of Iodine and Butylated Hydroxytoluene as
Radical Scavengers on the Nitration of Naphthalene (1
mmol) in the Presence of [Msim]NO (1 mmol)
3
a
entry
radical scavenger (mmol)
I2 (0.2)
time (min)
yield (%)
1
2
3
4
5
6
7
immediately
1440
84
45
30
22
52
41
35
Figure 3. Preparation of copper nitrate (with blue color) from copper
powder, evidence for the release of nitrogen dioxide.
I2 (0.5)
1440
I2 (1)
1440
BHT (0.2)
BHT (0.5)
BHT (1)
1440
Scheme 3. Identification of Nitrogen Dioxide and Oxygen
Using Copper Powder
1440
1440
a
Isolated yield of 1-nitronaphthalene.
Scheme 6. Production of 1,2-Diphenyldisulfane Using
Msim]NO3.
[
Scheme 4. Production of 1-Methylimidazolium Cation via
were studied. The reaction can easily be scaled up to 20 mmol
quantities without significant changes in the yield and the
reaction times. To study regeneration of the reagent, the
Hydrolizing Zwitterionic Salt by the Preduced H O in
2
Reaction Media
reaction of naphthalene with [Msim]NO was carried out
3
several times, and the resulting IL phases (unreacted [Msim]-
NO , the zwitterionic salt, and 1-methylimidazolium salt) were
3
Scheme 5. Trapping NO Radical with Iodine and Butylated
Hydroxytoluene (BHT)
2
combined. Water was added to the combined reaction mixtures,
and the mixture was stirred for 5 min and filtered ([Msim]NO3
and zwitterionic salt is miscible with water and separate from
remained starting material and product.) [Msim]NO and the
3
zwitterionic salt were hydrolyzed in aqueous media. A solution
of (10%) NaOH was then added to the reaction media, and the
mixture was stirred for 5 min, resulting in the formation of 1-
methylimidazole. The solution was extracted with ethyl acetate,
washed with water, and dried. Evaporation of the solvent gave
mechanism facilitates the efficient nitration of aniline to form 2-
nitroaniline and 4-nitroaniline in good yields and regioselectiv-
ity, despite the in situ formation of acid.
A wide range of aromatic compounds such as benzene,
chlorobenzene, toluene, o-xylene, naphthalene, anthracene,
phenols, anisol, thiophenol, 2-naphthol, and anilines were also
1
-methylimidazole (96% recovery). The recovered 1-methyl-
imidazole was reacted with chlorosulfonic acid to give
Msim]Cl. Then, [Msim]Cl was again reacted with nitric acid
100%) to produce [Msim]NO . The activity of the
[
(
nitrated with [Msim]NO (Table 2).
3
To maximize the unique advantages of this reagent, the
scalability, recoverability, and reusability of 1-methylimidazole
3
reproduced [Msim]NO as nitration agent was identical to
3
(
the main starting material for the synthesis of the reagent) and
before. The regeneration of this reagent is summarized in
Scheme 8.
regeneration of 3-methyl-1-sulfonic acid imidazolium nitrate
3
642
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The Journal of Organic Chemistry
Note
methane (50 mL) was added to a round-bottomed flask (100 mL),
and chlorosulfonic acid (0.605 g, 5.2 mmol) was then added dropwise
over a period of 5 min at room temperature. The reaction mixture was
then stirred for 20 min, and the dichloromethane was decanted after
the reaction mixture was allowed to settle for 5 min. The residue was
washed with dry dichloromethane (3 × 50 mL) to remove excess of
chlorosulfonic acid and dried under vacuum to give [Msim]Cl as a
Scheme 7. Plausible Mechanism for the Nitration of
Naphthalene Using [Msim]NO3
2
viscous colorless oil. Then, nitric acid 100% (0.315 g, 5 mmol) was
dropwise added to [Msim]Cl (0.993 g, 5 mmol) over a period of 5
min at room temperature under a continuous flow of nitrogen to
remove the HCl gas that is produced. The resulting mixture was
stirred for 10 min under these conditions to give [Msim]NO as a
3
viscous yellow red oil in 99% (1.113 g) yield. IR (Nujol) 680, 1062,
−
1
1
1
166, 1309, 1354, 1635, 2848, 2964, 3159, 3100−3400 cm ; H
NMR (300 MHz, DMSO-d ) δ (ppm) 3.85 (s, 3H, CH ), 7.59 (s,
H), 7.64 (s, 1H), 9.00 (s, 1H), 14.24 (s, 1H); C NMR (75 MHz,
DMSO-d ) δ (ppm) 36.1, 120.5, 124.0, 136.6; MS m/z = 226 (M +
6
3
13
1
+
6
+
+
+
+
1
), 225 (M ), 210 (M − CH ), 163 (M − NO ), 82 (M −
3
3
+
NO SO H), 67 (M − CH NO SO ). Anal. Calcd for C H N O S: C,
3
3
4
3
3
4
7
3
6
2
1.34; H, 3.13; N, 18.66. Found: C, 21.08; H, 3.24; N, 18.45.
General Procedure for the Nitration of Aromatic Com-
pounds. To a round-bottomed flask (10 mL) was added 3-methyl-1-
sulfonic acid imidazolium nitrate (0.225 g, 1 mmol, 0.128 mL) in dry
dichloromethane (2 mL). The aromatic compound (1 mmol) was
then added, and the mixture was stirred at room temperature the
required short time (10−1800 min). After the reaction was completed
(
monitored with TLC), dichloromethane (5 mL) was added to the
In summary, we have introduced a novel SAFIS ([Msim]-
reaction mixture, and the mixture was stirred for 2 min and separated.
The organic solvent was evaporated, and the product was easily
purified by short column chromatography. Note: For the nitration of
aniline and 4-methylaniline, after the reaction was completed, the
reaction mixture was basified to pH 8 by the slow addition of 10%
NaOH solution. The organic layer was separated, and the aqueous
layer was extracted with dichloromethane. The combined organic
NO ) as a highly efficient reagent for the nitration of aromatic
3
compounds. There are several attractive novelties about this
nitration agent. The acidic reagent and the source of in situ
NO are present in a single compound that also serves as the
2
ionic liquid.
solution was washed with brine, dried over MgSO , filtered, and
concentrated to give a crude product, which was purified with short
column chromatography.
General Procedure for the Use of Iodine or Butylated
Hydroxytoluene (BHT) as Radical Scavengers. To a round-
bottomed flask (10 mL) containing different amounts of iodine or
butylated hydroxytoluene (BHT) as radical scavengers (0.2, 0.5, and 1
mmol) in dry dichloromethane (2 mL) was added 3-methyl-1-sulfonic
4
EXPERIMENTAL SECTION
■
General Methods. The known products were identified by
comparison of their physical and spectral data (IR, H NMR,
NMR, and mass) with those reported in the literature. Progress of the
reactions was monitored by TLC.
1
13
C
General Procedure for the Preparation of the Ionic Liquid
[
Msim]NO . 1-Methylimidazole (0.410 g, 5 mmol) in dry dichloro-
3
Table 2. Nitration of Aromatic Compounds Using [Msim]NO at Room Temperature
3
o
mp/bp ( C)
reported [ref]
a
substrate
product
nitrobenzene (1)
time (min)
yield (%)
found
benzene
toluene
O-xylene
2
82 (0.1009 g)
70 (0.0959 g)
89 (0.1345 g)
84 (0.1455 g)
80 (0.1785 g)
85 (0.1609 g)
51 (0.0707 g)
42 (0.0582 g)
95 (0.2194 g)
90 (0.1632 g)
92 (0.1406 g)
90 (0.1960 g)
75 (0.1634 g)
47 (0.0646 g)
39 (0.0541 g)
81 (0.1231 g)
75 (0.1178 g)
210−211
52−54
30−32
208−210 [4a]
53−55 [4a]
30−31 [4a]
70−71 [4a]
145−146 [9]
103 [9]
4-nitrotoluene (2)
2
4-nitro-o-xylene (3)
1-nitronaphthalene (4)
9-nitroanthracene (5)
1-nitronaphtalene −2-ol (6)
2-nitrophenol (7a)
1
naphthalene
anthracene
naphtalene-2-ol
phenol
immediately
59−61
immediately
137−139
100−103
43−47
113−115
180−182
121−123
52−54
82−83
62−64
71−73
147−151
110−112
immediately
immediately
44 [10]
4
-nitrophenol (7b)
immediately
113−114 [4a]
180−184 [4c]
122−124 [4c]
52−54 [4a]
84 [4c]
biphenyl-4,4′-diol
3-nitrobiphenyl-4,4′-diol (8)
1-(4-hydroxy-3-nitrophenyl)ethanone (9)
4-nitroanisol (10)
immediately
1
-(4-hydroxyphenyl)ethanone
anisol
-bromophenol
immediately
1
4
4-bromo-2-nitrophenol (11)
1,2-diphenyldisulfide (12)
2-nitroaniline (13a)
immediately
benzenethiol
aniline
5
62−64 [4a]
69−72 [11]
148 [12]
2
4
-nitroaniline (13b)
2
4
-methylaniline
2-nitro-4-methylaniline (14)
1-chloro-4-nitrobenzene (15)
15
30
115−117 [13]
82−83 [4a]
b
chlorobenzene
82−84
a
b
Isolated yield was calculated on the basis of the reaction of aromatic compound (1 mmol) with [Msim]NO (1 mmol). This reaction was carried
3
out in the absence of dichloromethane.
3
643
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The Journal of Organic Chemistry
Note
Scheme 8. Regeneration of [Msim]NO3
acid imidazolium nitrate (0.225 g, 1 mmol, 0.128 mL). Naphthalene
1,2-Diphenyldisulfide (12). White solid; isolated yield 75% (0.1634
−1 1
(0.128 g, 1 mmol) was then added, and the mixture was stirred at
g). IR (KBr) 510, 686, 1573 cm ; H NMR (300 MHz, CDCl ) δ
3
13
room temperature. After 24 h, dichloromethane (5 mL) was added to
the reaction mixture, and the mixture was stirred for 2 min and
separated. The organic solvent was evaporated, and the product was
purified by short column chromatography.
(ppm) 7.29−7.43 (m, 6H), 7.62- 7.64 (m, 4H) ; C NMR (75 MHz,
CDCl ) δ (ppm) 127.3, 127.6, 129.2, 137.1.
2-Nitroaniline (13a). Orange solid; isolated yield 47% (0.0646 g).
3
−1 1
IR (KBr) cm ; H NMR (500 MHz, CDCl ) δ (ppm) 6.13 (s, 2H,
3
NH ), 6.69 (t, J = 7.7 Hz, 1H), 6.8 (dd, J = 8.8 Hz, 0.9 Hz, 1H), 7.36
Spectral Data of the Products. Nitrobenzene (1). Pale yellow
oil; isolated yield 82% (0.1009 g). IR (Nujol) 704, 1348, 1590
2
1
3
(
t, J = 7.7 Hz, 1H), 8.10 (dd, J = 8.6 Hz, 1.3 Hz, 1H); C NMR (125
−1
1
MHz, CDCl ): 117.3, 119.2, 126.5, 132.5, 136.1, 154.2.
cm ; H NMR (500 MHz, CDCl ) δ (ppm) 7.56 (t, J = 7.1
3
3
Hz, 2H), 7.72 (t, J = 7.5 Hz, 1H), (dd, J = 8.3 Hz, 1.15 Hz,
4
-Nitroaniline (13b). Yellow solid; isolated yield 39% (0.0541 g).
−1 1
H); 13C NMR (125 MHz, CDCl ) δ (ppm) 123.8, 129.7,
35.0, 158.5.
IR (KBr) 840, 1298, 1587, 3360, 3481 cm ; H NMR (500 MHz,
1
1
3
CDCl ) δ (ppm) 6.60 (d, J = 9.1 Hz, 2H), 6.68 (s, 2H, NH ), 7.94 (d,
3
2
13
J = 9.1 Hz, 2H); C NMR (125 MHz, CDCl ) δ (ppm) 113.2, 127.2,
3
1
-Nitronaphthalene (4). Yellow solid; isolated yield 84% (0.1455
−1
1
136.5, 156.5.
g). IR (KBr) 653, 1336, 1519 cm ; H NMR (300 MHz, CDCl ) δ
3
4
-Methyl-2-nitroaniline (14). Red-Brown solid; isolated yield 81%
(
ppm) 7.54 (t, J = 7.8 Hz, 1H), 7.62 (t, J = 7.2 Hz, 1H), 7.72 (t, J = 6.9
−1 1
(
0.1231 g). IR (KBr) 810, 867, 1382, 1508, 3016, 3043 cm ; H
Hz, 1H), 7.96 (d, J = 8.1 Hz, 1H), 8.12 (d, J = 8.1 Hz, 1H), 8.23 (d, J
7.5 Hz, 1H), 8.56 (d, J = 8.7 Hz, 1H); 13C NMR (75 MHz, CDCl3)
δ (ppm)123.5, 124.4, 124.5, 125.5, 127.7, 129.0, 129.8, 134.7, 135.0.
-Nitroanthracene (5). Yellow solid; isolated yield 80% (0.1785 g).
NMR (300 MHz, DMSO-d ) δ (ppm) 2.20 (s, 3H), 7.04 (d, J = 6.0
6
=
Hz, 1H), 7.16 (t, J = 8.4 Hz, 1H), 7.26 (d, J = 3.6 Hz, 1H), 8.95 (s, 2H,
13
NH ); C NMR (75 MHz, DMSO-d ) δ (ppm) 20.9, 120.3, 122.3,
2
6
9
+
+
+
1
23.0, 130.1, 136.1. MS m/z = 153 (M + 1), 152 (M ), 106 (M −
−1
1
IR (KBr) 692, 1369, 1517 cm ; H NMR (500 MHz, CDCl ) δ
3
NO ).
2
(
6
ppm) 7.59 (t, J = 5.7 Hz, 2H), 7.68 (t, J = 6.0 Hz, 2H), 7.98 (d, J =
.0 Hz, 2H), 8.09 (d, J = 6.0 Hz, 2H), 8.63 (s, 1H); C NMR (125
1
-Chloro-4-nitrobenzene (15). Yellow solid; isolated yield 75%
13
1
(
0.1178 g); H NMR (300 MHz, CDCl ) δ (ppm) 7.50 (d, J = 9.0 Hz,
2H), 8.15 (d, J = 9.0 Hz, 2H); C NMR (75 MHz, DMSO-d ) δ
3
MHz, CDCl ) δ (ppm) 121.8, 123.1, 126.6, 128.8, 129.3, 130.7, 131.2,
13
3
6
1
44.9.
-Nitronaphthalen-2-ol (6). Yellow solid; isolated yield 85%
(
ppm) 124.8, 129.5, 141.2, 146.5.
1
−1
1
(
0.1609 g). IR (KBr) 717, 1373, 1539, 3150 cm ; H NMR (300
ASSOCIATED CONTENT
MHz, CDCl ) δ (ppm) 7.26 (t, J = 5.7 Hz, 1H), 7.50 (t, J = 6.9 Hz,
■
3
1
H), 7.73 (t, J = 7.2 Hz, 1H), 7.81 (d, J = 7.8 Hz, 1H), 8.0 (d, J = 9.0
* Supporting Information
S
13
Hz, 1H), 8.91 (d, J = 8.7 Hz, 1H), 12.23 (s, 1H, OH); C NMR (75
Experimental procedures and compound characterization data.
This material is available free of charge via the Internet at
http://pubs.acs.org.
MHz, CDCl ) δ (ppm) 119.3, 123.2, 125.6, 126.9, 128.6, 129.3, 131.0,
3
+
+
+
1
39.1, 139.2, 158.8. MS m/z = 190 (M + 1), 189 (M ), 143 (M −
NO ).
2
2
-Nitrophenol (7a). Yellow solid; isolated yield 51% (0.0707 g). IR
−1 1
(
(
(
KBr) 748, 1373, 1533, 3230 cm ; H NMR (500 MHz, CDCl ) δ
AUTHOR INFORMATION
3
■
ppm) 7.01 (t, J = 8.5 Hz, 1H), 7.17 (dd, J = 7.2 Hz, 1.2 Hz, 1H), 7.60
t, J = 7.8 Hz, 1H), 8.11 (dd, J = 6.9 Hz, 1.6 Hz, 1H), 10.59 (s, 1H,
Corresponding Author
*E-mail: mzolfigol@yahoo.com; khazaei_1326@yahoo.com.
13
OH); C NMR (125 MHz, CDCl ) δ (ppm) 120.3, 120.6, 125.4,
1
3
34.1, 137.9, 155.5.
Notes
4
-Nitrophenol (7b). Yellow solid; isolated yield 42% (0.0582 g). IR
−1
1
The authors declare no competing financial interest.
(
(
1
KBr) 846, 1338, 1494, 1346 cm ; H NMR (300 MHz, CDCl ) δ
3
ppm) 6.17 (S, 1H, OH), 6.93 (d, J = 9.0 Hz, 1H), 8.17 (d, J = 9.0 Hz,
H); 13C NMR (75 MHz, CDCl ) δ (ppm) 115.7, 126.3, 161.3. MS
3
ACKNOWLEDGMENTS
■
+
+
+
m/z = 140 (M + 1), 139 (M ), 93 (M − NO ).
2
The authors gratefully acknowledge partial support of this work
by the Research Affairs Office of Bu-Ali Sina University (Grant
Number 32-1716 entitled development of chemical methods,
reagents and molecules), and Center of Excellence in
Development of Chemical Method (CEDCM), Hamedan,
I.R. Iran.
4
-Bromo-2-nitrophenol (11). Yellow solid; isolated yield 90%
−1 1
(
0.1960 g). IR (KBr) 883, 970, 1313, 1527, 3273 cm ; H NMR (300
MHz, CDCl ) δ (ppm) 7.07 (d, J = 8.7 Hz, 1H), 7.66 (dd, J = 8.7 Hz,
2
3
13
.4 Hz, 1H), 8.24 (d, J = 2.1 Hz, 1H), 10.49 (s, 1H, OH); C NMR
(
75 MHz, CDCl ) δ (ppm) 111.7, 121.7, 127.3, 140.3, 142.9, 154.1.
3
+
+
+
MS m/z = 219 (M + 1), 218 (M ), 170 (M − NO ).
2
3
644
dx.doi.org/10.1021/jo300137w | J. Org. Chem. 2012, 77, 3640−3645

The Journal of Organic Chemistry
Note
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