Reactions of Nitroarenes with Secondary and Tertiary Carbanions Bearing Both a Leaving Group and Electron-Withdrawing Group: An Approach to Dihydronaphth[2,1-c]isoxazole N-oxides and Dihydroisoxazolo[4,3-f]quinoline N-oxides

Article abstract of DOI:10.1002/jhet.5570400613

2-Nitronaphthalene (1) and 6-nitroquinoline (2) underwent direct cyclocondensation with secondary and tertiary carbanions derived from a methylene and methine group bearing both a leaving group and electron-withdrawing group (e.g., methyl chloroacetate, ethyl chloroacetate, chloroacetonitrile, methyl 2-chloropropionate, ethyl 2-chloropropionate and 2-chloropropionitrile) in the sodium hydride/N,N-dimethylformamide system at low temperature, giving the corresponding dihydronaphth[2,1-c]isoxazole N-oxides 3 and dihydroisoxazolo[4,3-f]quinoline N-oxides 4. On the other hand, nitroarenes 1 and 2 reacted with secondary carbanions in the sodium hydride/tetrahydrofuran system to yield the corresponding conventional vicarious nucleophilic substitution (VNS) products 5 and 6.

Full text of DOI:10.1002/jhet.5570400613

Nov-Dec 2003
1051
Reactions of Nitroarenes with Secondary and Tertiary Carbanions
Bearing Both a Leaving Group and Electron-Withdrawing Group:
An Approach to Dihydronaphth[2,1-c]isoxazole N-oxides and
Dihydroisoxazolo[4,3-f]quinoline N-oxides
Hiroshi Maruoka and Yukihiko Tomioka*
Faculty of Pharmaceutical Sciences, Fukuoka University,
8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan
Received March 14, 2003
2-Nitronaphthalene (1) and 6-nitroquinoline (2) underwent direct cyclocondensation with secondary and
tertiary carbanions derived from a methylene and methine group bearing both a leaving group and electron-
withdrawing group (e.g., methyl chloroacetate, ethyl chloroacetate, chloroacetonitrile, methyl 2-chloropro-
pionate, ethyl 2-chloropropionate and 2-chloropropionitrile) in the sodium hydride/N,N-dimethylformamide
system at low temperature, giving the corresponding dihydronaphth[2,1-c]isoxazole N-oxides 3 and dihy-
droisoxazolo[4,3-f]quinoline N-oxides 4. On the other hand, nitroarenes 1 and 2 reacted with secondary car-
banions in the sodium hydride/tetrahydrofuran system to yield the corresponding conventional vicarious
nucleophilic substitution (VNS) products 5 and 6.
J. Heterocyclic Chem., 40, 1051 (2003).
Nitro compounds, especially aromatic nitro compounds,
Recently, much attention has been paid to the development
of new environmentally favorable routes for preparing
commercially relevant chemical intermediates and prod-
ucts [9-14]. In this context, we have recently become inter-
ested in the development of new synthetic schemes for the
construction of a series of 2,1-benzisoxazoles using
applied VNS.
are used as intermediates in the synthesis of fine chemi-
cals. Of course, they are very important for the preparation
of dyes and explosives. The versatility of nitro compounds
in organic synthesis is largely due to their easy availability
and transformation into a variety of diverse functionalities
[1-3]. Aromatic nitro compounds undergo nucleophilic
aromatic substitutions with various nucleophiles.
Nucleophilic aromatic substitution of hydrogen (NASH)
process is an ideal process because NASH reactions gener-
ate functionalized aromatics without the need for halo-
genated materials. The vicarious nucleophilic substitution
(VNS), pioneered by Makosza and coworkers, offers a
selective mild method for the controlled substitution of
hydrogen atoms of aromatic systems (Scheme 1) [4-8].
Available synthetic routes to 2-isoxazoline N-oxides
proceed from either 3-halo-1-nitroalkanes or 1,3-dini-
troalkanes. The methods were discovered and devel-
oped by Kohler and coworkers (Scheme 2) [15,16]. This
reaction suggests the possibility that when aromatic
nitro compound is treated with secondary or tertiary car-
banion derived from a methylene or methine group bear-
ing both a leaving group and electron-withdrawing
group in the presence of an appropriate base/solvent sys-
tem, the σ-adduct initially formed may undergo cycliza-
tion to furnish 2,1-benzisoxazole N-oxide. Isoxazoles
and 2,1-benzisoxazoles are versatile compounds that
have found application as intermediates and products in
biological and pharmaceutical chemistry [17-22].
Several investigators have shown that aromatic nitro
compounds react with nucleophiles to generate 2,1-ben-
zisoxazoles [23-25]. We now report in this paper new
approach to the one-pot synthesis of dihydronaphth[2,1-
c]isoxazole N-oxides and dihydroisoxazolo[4,3-f]-
quinoline N-oxides.
Scheme 1
When a mixture of 2-nitronaphthalene (1) with methyl
chloroacetate in the presence of sodium hydride in N,N-
dimethylformamide was stirred at -10° for 4 hours, methyl
1,9b-dihydronaphth[2,1-c]isoxazole-1-carboxylate 3-
oxide (3a) was obtained in 68% yield, and the VNS prod-
uct was not observed with little or no creation. In contrast,
in the sodium hydride/tetrahydrofuran system in stead of
the sodium hydride/N,N-dimethylformamide system, the
reaction of 1 with methyl chloroacetate gave the VNS

1052
H. Maruoka and Y. Tomioka
Vol. 40
Scheme 2
N-oxides 4a-f (Table 1). In these reactions, products 3b,
3c, 3f, 4a-c and 4e were obtained as a mixture of two
diastereomers as well as 3a (see experimental section).
While, in the sodium hydride/tetrahydrofuran system, 1
and 2 reacted with secondary carbanions to yield the corre-
sponding VNS products 5b,c and 6a-c. In the case of ter-
tiary carbanions, the VNS reaction was not observed and
nitroarenes were recovered unchanged. Elemental analy-
ses and spectral data of 3-6 are consistent with the
assigned structures.
The formation of 3-6 can be explained in terms of
Scheme 3. An addition of secondary or tertiary carbanions
at positions 1 (compound 1) and 5 (compound 2) in the
sodium hydride/N,N-dimethylformamide system gives the
σ-adduct A, which undergoes intramolecular cyclization
and dechlorination to form the 2,1-benzisoxazole N-oxides
3 and 4. On the other hand, in the sodium hydride/tetrahy-
drofuran system, an elimination of hydrogen chloride from
the σ-adduct A produces B which undergoes tautomeriza-
tion to afford the VNS products 5 and 6. Generally, the VNS
reaction results in replacement of an aromatic hydrogen
product 5a [26] in 78% yield (Table 1). The ir spectrum of
-1
3a displays a band at 1738 cm due to a carbonyl group,
-1
on the other hand, that of 5a shows a band at 1735 cm .
The H nmr spectrum of 3a shows two singlets at δ 3.47
1
and 3.78 for a methyl group of a methoxy group, two dou-
blets at δ 3.97 and 4.20 for a 1-methine group and two
doublets at δ 1.57 and 3.48 for a 9b-methine group,
whereas that of 5a appears as a three-proton singlet at δ
3.73 for the methyl of a methoxy group and a two-proton
singlet at δ 4.41 for a methylene group. Mass spectra and
elemental analyses of 3a and 5a exhibit the same elemen-
tal composition C H NO (see experimental section).
13 11
4
These observations indicate that the structure of 3a is
obviously different from that of 5a. Furthermore, 3a exists
as two diastereomers, which would probably be formed by
an effect of the configuration of methoxycarbonyl group at
the 1-position. On the basis of these results, 3a was
assigned as methyl 1,9b-dihydronaphth[2,1-c]isoxazole-1-
carboxylate N-oxide, and the structure of 5a was deter-
mined as the VNS product. Similarly, the reactions of 1
and 6-nitroquinoline (2) with secondary and tertiary car-
banions in the sodium hydride/N,N-dimethylformamide
system gave the corresponding dihydronaphth[2,1-c]isox-
azole N-oxides 3b-f and dihydroisoxazolo[4,3-f]quinoline
atom by a functionalised alkyl substituent. It is typically
characterized by the addition to a nitroarene of a nucle-
ophile bearing both an electron-withdrawing group and a
leaving group at the reactive center [27,28]. In contrast,
our results indicate that a new type of cyclocondensation
occurs in the sodium hydride/N,N-dimethylformamide
system and the VNS reaction dose not take place. To our
knowledge, this type of cyclocondensation between
nitroarenes and secondary or tertiary carbanions has not
previously been reported. A new type of cyclocondensa-
tion, not the VNS reaction, depends on three factors:

Nov-Dec 2003
Reactions of Nitroarenes with Secondary and Tertiary Carbanions
1053
Scheme 3
examined the decarboxylation of 5a,b in order to confirm
their structure. The reaction of 5a,b with sodium iodide
and water in N,N-dimethylformamide or dimethylsulfox-
ide according to the method of Gurjar et al. [32] proceeded
smoothly to give 1-methyl-2-nitronaphthalene (10) [33].
In conclusion, we have developed a novel and efficient
method for the construction of dihydronaphth[2,1-c]-
Scheme 4
structure of the carbanions, structure of the nitroarenes and
the reaction conditions.
We next tried the reaction of m-dinitrobenzene with sec-
ondary and tertiary carbanions in the sodium hydride/N,N-
dimethylformamide system. In this case, the reaction
afforded the VNS products 7a-e and the desired 2,1-ben-
zisoxazole N-oxides could not be obtained (Table 2). It is
well known that several investigators [29-31] have
reported the conventional VNS reaction of m-dinitroben-
zene as the substrate and the VNS products are always
obtained. In contrast, on the basis of our results, in bicyclic
nitroarenes such as 2-nitronaphthalene and 6-nitroquino-
line, the σ-adduct proceeds mainly cyclocondensation in
the sodium hydride/N,N-dimethylformamide system. It
makes us believe that the reaction mechanism is different
from that of m-dinitrobenzene. The reason is not clear.
During our study of the synthesis of dihydronaphth-
[2,1-c]isoxazole N-oxides, we found that compounds 3a,b
reacted with methyl (or ethyl) iodide in the presence of
sodium hydride in N,N-dimethylformamide at room tem-
perature to give 8a,b and 9 (Scheme 4). This ring conver-
sion probably proceeds through the intermediate C, which
would undergoes ring opening and elimination of hydro-
gen iodide to give 8a,b. Furthermore, cyclization of the
(Z)-isomers of 8a,b presumably affords the same 2H-
naphth[2,1-c][1,2]oxazin-2-one (9). Finally, we have

1054
H. Maruoka and Y. Tomioka
Vol. 40
4.20-4.26 (m, 1.07H, CO CH CH ), 6.62 (d, J = 10 Hz, 0.53H,
isoxazole N-oxides and dihydroisoxazolo[4,3-f]quinoline
N-oxides, which is based on the direct condensation of
2-nitronaphthalene and 6-nitroquinoline with secondary
and tertiary carbanions in the sodium hydride/N,N-
dimethylformamide system.
2
2
3
4-H), 6.68 (d, J = 10 Hz, 0.47H, 4-H), 6.72 (d, J = 10 Hz, 0.53H,
5-H), 6.76 (d, J = 10 Hz, 0.47H, 5-H), 7.25-7.36 (m, 3H, 6, 7 and
8-H), 7.46-7.48 (m, 0.47H, 9-H), 7.52-7.53 ppm (m, 0.53H, 9-H);
+
ms: m/z 260 [M+H] .
Anal. Calcd. for C
H NO : C, 64.86; H, 5.05; N, 5.40.
14 13 4
Found: C, 64.84; H, 5.05; N, 5.46.
EXPERIMENTAL
1,9b-Dihydronaphth[2,1-c]isoxazole-1-carbonitrile 3-oxide (3c).
This compound was obtained as colorless columns (0.57 g,
27%), mp 172-174° dec (acetone-petroleum ether); ir (potassium
All melting points are uncorrected. The ir spectra were
recorded on a JASCO FT/IR-230 spectrometer. The H nmr spec-
1
-1
1
bromide): ν 2244 (C≡N) cm ; H nmr (deuteriochloroform): δ
3.42 (d, J = 10.5 Hz, 1H, 9b-H), 4.08 and 4.09 (d, J = 10.5 Hz,
1H, 1-H), 6.76 and 6.77 (d, J = 10 Hz, 1H, 4-H), 6.95 (d, J = 10
Hz, 1H, 5-H), 7.39-7.43 (m, 3H, 6, 7 and 8-H), 7.51-7.53 ppm
tra were recorded on a JEOL JNM-A 500 spectrometer (500
MHz). Chemical shifts (δ) are reported in parts per million (ppm)
relative to tetramethylsilane as internal standard. Positive FAB
mass spectra were obtained on a JEOL JMS-HX 110 spectrome-
ter. Elemental analyses were performed on a YANACO MT-6
CHN analyzer.
+
(m, 1H, 9-H); ms: m/z 212 [M ].
Anal. Calcd. for C H N O : C, 67.92; H, 3.80; N, 13.20.
12
8 2 2
Found: C, 67.87; H, 3.90; N, 13.14.
General Procedure for the Preparation of 3a-f and 4a-f from 1
and/or 2 and Secondary and/or Tertiary Carbanions.
Methyl 1,9b-Dihydro-1-methylnaphth[2,1-c]isoxazole-1-car-
boxylate 3-oxide (3d).
To a solution of nitroarenes 1 (1.73 g, 10 mmoles) or 2 (1.74 g,
10 mmoles) and methyl chloroacetate (3.26 g, 30 mmoles), ethyl
chloroacetate (3.68 g, 30 mmoles), chloroacetonitrile (2.27 g, 30
mmoles), methyl 2-chloropropionate (3.68 g, 30 mmoles), ethyl 2-
chloropropionate (4.10 g, 30 mmoles) or 2-chloropropionitrile
(2.69 g, 30 mmoles) in N,N-dimethylformamide (30 ml) was added
60% sodium hydride (1.20 g, 30 mmoles) at –10° (in the case of
the preparation of 3a-c and 4a-c) or 0~5° (in the case of the prepa-
ration of 3d-f and 4d-f) with stirring. After the mixture was stirred
at –10° for 4 hours (3a-c and 4a-c) or 0~5° for 2 hours (3d-f and
4d-f), cold water was added to the reaction mixture. The resulting
mixture was extracted with chloroform. The extract was dried over
anhydrous sodium sulfate and concentrated in vacuo. The residue
was purified by column chromatography on silica gel with chloro-
form as the eluent to afford 3a-f and 4d-f, or on alumina with chlo-
roform as the eluent to yield 4a-c. In the case of the preparation of
3c, the first elution gave the starting material 1 (0.43 g, 25%).
This compound was obtained as colorless prisms (2.17 g,
84%), mp 111-113° (diethyl ether-petroleum ether); ir (potassium
bromide): ν 1745 (C=O) cm ; H nmr (deuteriochloroform): δ
-1
1
0.87 (s, 3H, 1-Me), 3.79 (s, 3H, CO Me), 4.30 (s, 1H, 9b-H), 6.55
2
(d, J = 10 Hz, 1H, 4-H), 6.79 (d, J = 10 Hz, 1H, 5-H), 7.26-7.36
(m, 3H, 6, 7 and 8-H), 7.48-7.50 ppm (m, 1H, 9-H); ms: m/z 260
+
[M+H] .
Anal. Calcd. for C
H NO : C, 64.86; H, 5.05; N, 5.40.
14 13 4
Found: C, 64.85; H, 5.07; N, 5.37.
Ethyl 1,9b-Dihydro-1-methylnaphth[2,1-c]isoxazole-1-carboxyl-
ate 3-oxide (3e).
This compound was obtained as pale yellow oil (2.65 g, 97%),
-1
1
ir (neat): ν 1728 (C=O) cm ; H nmr (deuteriochloroform): δ
0.87 (s, 3H, 1-Me), 1.29 (t, J = 7.3 Hz, 3H, CO CH CH ), 4.24
2
2
3
(q, J = 7.3 Hz, 2H, CO CH CH ), 4.29 (s, 1H, 9b-H), 6.56 (d, J =
2
2
3
10 Hz, 1H, 4-H), 6.78 (d, J = 10 Hz, 1H, 5-H), 7.28-7.36 (m, 3H,
Methyl 1,9b-Dihydronaphth[2,1-c]isoxazole-1-carboxylate
3-oxide (3a).
+
6, 7 and 8-H), 7.48-7.50 ppm (m, 1H, 9-H); ms: m/z 274 [M+H] .
Anal. Calcd. for C
H NO •0.1H O: C, 65.92; H, 5.53; N,
15 15 4 2
5.13. Found: C, 65.48; H, 5.71; N, 4.90.
This compound was obtained as colorless needles (1.67 g,
68%), mp 88-89° (diethyl ether-petroleum ether); ir (potassium
1,9b-Dihydro-1-methylnaphth[2,1-c]isoxazole-1-carbonitrile
3-oxide (3f).
-1
1
bromide): ν 1738 (C=O) cm ; H nmr (deuteriochloroform): δ
1.57 (d, J = 6.7 Hz, 0.47H, 9b-H), 3.47 (s, 1.6H, CO Me), 3.48
2
This compound was obtained as colorless prisms (1.94 g,
86%), mp 103-105° (diethyl ether-petroleum ether); ir (potassium
(d, J = 11.3 Hz, 0.53H, 9b-H), 3.78 (s, 1.4H, CO Me), 3.97 (d, J =
2
11.3 Hz, 0.53H, 1-H), 4.20 (d, J = 6.7 Hz, 0.47H, 1-H), 6.63 (d,
J = 10 Hz, 0.47H, 4-H), 6.67 (d, J = 10 Hz, 0.53H, 4-H), 6.72 (d,
J = 10 Hz, 0.47H, 5-H), 6.79 (d, J = 10 Hz, 0.53H, 5-H), 7.25-
7.37 (m, 3H, 6, 7 and 8-H), 7.46-7.48 (m, 0.53H, 9-H), 7.52-7.54
-1
1
bromide): ν 2241 (C≡N) cm ; H nmr (deuteriochloroform): δ
0.97 (s, 1.4H, 1-Me), 1.75 (s, 1.6H, 1-Me), 3.94 (s, 0.53H, 9b-H),
4.36 (s, 0.47H, 9b-H), 6.76 (d, J = 10 Hz, 0.47H, 4-H), 6.80 (d,
J = 10 Hz, 0.53H, 4-H), 6.82 (d, J = 10 Hz, 0.47H, 5-H), 6.86 (d,
J = 10 Hz, 0.53H, 5-H), 7.31-7.42 (m, 3H, 6, 7 and 8-H), 7.48-
+
ppm (m, 0.47H, 9-H); ms: m/z 246 [M+H] .
Anal. Calcd. for C
H NO : C, 63.67; H, 4.52; N, 5.71.
13 11 4
+
7.53 ppm (m, 1H, 9-H); ms: m/z 227 [M+H] .
Found: C, 63.66; H, 4.53; N, 5.63.
Anal. Calcd. for C
Found: C, 69.02; H, 4.56; N, 12.36.
H N O : C, 69.02; H, 4.46; N, 12.38.
13 10 2 2
Ethyl 1,9b-Dihydronaphth[2,1-c]isoxazole-1-carboxylate
3-oxide (3b).
Methyl 1,9b-Dihydroisoxazolo[4,3-f]quinoline-1-carboxylate
3-oxide (4a).
This compound was obtained as pale yellow oil (2.28 g, 88%),
-1
1
ir (neat): ν 1731 (C=O) cm ; H nmr (deuteriochloroform): δ
0.99 (t, J = 7.3 Hz, 1.4H, CO CH CH ), 1.28 (t, J = 7.3 Hz, 1.6H,
This compound was obtained as colorless prisms (0.39 g,
16%), mp 94-96° (diethyl ether-petroleum ether); ir (potassium
2
2
3
CO CH CH ), 1.55 (d, J = 6.7 Hz, 0.53H, 9b-H), 3.48 (d, J =
2
2
3
-1
1
bromide): ν 1743 (C=O) cm ; H nmr (deuteriochloroform): δ
11.3 Hz, 0.47H, 9b-H), 3.86-3.93 (m, 0.93H, CO CH CH ), 3.94
2
2
3
1.64 (d, J = 6.7 Hz, 0.47H, 9b-H), 3.49 (s, 1.6H, CO Me), 3.54
(d, J = 11.3 Hz, 0.47H, 1-H), 4.18 (d, J = 6.7 Hz, 0.53H, 1-H),
2

Nov-Dec 2003
Reactions of Nitroarenes with Secondary and Tertiary Carbanions
1055
(d, J = 11.3 Hz, 0.53H, 9b-H), 3.80 (s, 1.4H, CO Me), 3.98 (d, J =
1,9b-Dihydro-1-methylisoxazolo[4,3-f]quinoline-1-carbonitrile
3-oxide (4f).
2
11.3 Hz, 0.53H, 1-H), 4.21 (d, J = 6.7 Hz, 0.47H, 1-H), 6.87 (d,
J = 10 Hz, 0.47H, 4-H), 6.96 (d, J = 10 Hz, 0.53H, 4-H), 7.00 (d,
J = 10 Hz, 0.53H, 5-H), 7.04 (d, J = 10 Hz, 0.47H, 5-H), 7.25-
7.29 (m, 1H, 8-H), 7.77-7.79 (m, 0.53H, 9-H), 7.83-7.85 (m,
This compound was obtained as pale orange plates (1.68 g,
74%), mp 134-135° (acetone-petroleum ether); ir (potassium bro-
-1
1
mide): ν 2239 (C≡N) cm ; H nmr (deuteriochloroform): δ 1.04
(s, 3H, 1-Me), 4.40 (s, 1H, 9b-H), 7.05 (d, J = 10 Hz, 1H, 4-H),
7.09 (d, J = 10 Hz, 1H, 5-H), 7.35 (dd, J = 5, 8 Hz, 1H, 8-H), 7.87
(dd, J = 1.5, 8 Hz, 1H, 9-H), 8.66 ppm (dd, J = 1.5, 5 Hz, 1H,
+
0.47H, 9-H), 8.58-8.59 ppm (m, 1H, 7-H); ms: m/z 247 [M+H] .
Anal. Calcd. for C
H N O : C, 58.54; H, 4.09; N, 11.38.
12 10 2 4
Found: C, 58.61; H, 4.13; N, 11.27.
+
7-H); ms: m/z 228 [M+H] .
Ethyl 1,9b-Dihydroisoxazolo[4,3-f]quinoline-1-carboxylate
3-oxide (4b).
Anal. Calcd. for C H N O : C, 63.43; H, 3.99; N, 18.49.
12
9 3 2
Found: C, 63.48; H, 4.07; N, 18.50.
This compound was obtained as colorless needles (1.33 g,
51%), mp 64-66° (diethyl ether-petroleum ether); ir (potassium
General Procedure for the Preparation of VNS Products 5a-c and
6a-c from 1 and/or 2 and Secondary Carbanions.
-1
1
bromide): ν 1738 (C=O) cm ; H nmr (deuteriochloroform): δ
1.01 (t, J = 7 Hz, 1.6H, CO CH CH ), 1.29 (t, J = 7 Hz, 1.4H,
2
2
3
To a solution of nitroarenes 1 (1.73 g, 10 mmoles) or 2 (1.74 g, 10
mmoles) and methyl chloroacetate (3.26 g, 30 mmoles), ethyl
chloroacetate (3.68 g, 30 mmoles) or chloroacetonitrile (2.27 g, 30
mmoles) in tetrahydrofuran (30 ml) was added 60% sodium hydride
(1.20 g, 30 mmoles) with stirring and ice-cooling. After the mixture
was stirred at room temperature for 4 hours (in the case of the prepa-
ration of 5a-c and 6a,c) or refluxed for 1 hour (6b), cold water was
added to the reaction mixture. The resulting mixture was extracted
with ethyl acetate. The extract was dried over anhydrous sodium
sulfate and concentrated in vacuo. The residue was purified by col-
umn chromatography on silica gel with chloroform as the eluent to
give 5a-c and 6a-c. In the case of the preparation of 5c, the first elu-
tion gave the starting material 1 (0.18 g, 10%).
CO CH CH ), 1.62 (d, J = 6.7 Hz, 0.47H, 9b-H), 3.55 (d, J =
2
2
3
11.3 Hz, 0.53H, 9b-H), 3.88-3.95 (m, 1.07H, CO CH CH ), 3.96
2
2
3
(d, J = 11.3 Hz, 0.53H, 1-H), 4.20 (d, J = 6.7 Hz, 0.47H, 1-H),
4.21-4.28 (m, 0.93H, CO CH CH ), 6.86 (d, J = 10 Hz, 0.47H,
2
2
3
4-H), 6.98 (s, 1H, 4 and 5-H), 7.04 (d, J = 10 Hz, 0.53H, 5-H),
7.24-7.28 (m, 1H, 8-H), 7.77-7.79 (m, 0.53H, 9-H), 7.84-7.85 (m,
+
0.47H, 9-H), 8.57-8.59 ppm (m, 1H, 7-H); ms: m/z 261 [M+H] .
Anal. Calcd. for C
H N O : C, 60.00; H, 4.65; N, 10.76.
13 12 2 4
Found: C, 59.92; H, 4.63; N, 10.69.
1,9b-Dihydroisoxazolo[4,3-f]quinoline-1-carbonitrile 3-oxide
(4c).
This compound was obtained as colorless needles (0.25 g,
12%), mp 162-164° dec (acetone-petroleum ether); ir (potassium
Methyl 2-Nitro-1-naphthaleneacetate (5a) [26].
-1
1
bromide): ν 2245 (C≡N) cm ; H nmr (deuteriochloroform): δ
3.50 (d, J = 10.7 Hz, 1H, 9b-H), 4.10 and 4.11 (d, J = 10.7 Hz,
1H, 1-H), 7.06 (d, J = 10.4 Hz, 1H, 4-H), 7.18 (d, J = 10.4 Hz, 1H,
5-H), 7.34 (dd, J = 5, 8 Hz, 1H, 8-H), 7.84 (dd, J = 1.5, 8 Hz, 1H,
9-H), 8.69 ppm (dd, J = 1.5, 5 Hz, 1H, 7-H); ms: m/z 214
This compound was obtained as yellow needles (1.91 g, 78%),
mp 101-103° (acetone-petroleum ether); ir (potassium bromide):
-1
1
ν 1735 (C=O) cm ; H nmr (deuteriochloroform): δ 3.73 (s, 3H,
CO Me), 4.41 (s, 2H, CH CO Me), 7.65-7.69 (m, 2H, 6' and
2
2
2
7'-H), 7.89-7.97 (m, 3H, 4', 5' and 8'-H), 8.12-8.13 ppm (m, 1H,
+
[M+H] .
+
3'-H); ms: m/z 246 [M+H] .
Anal. Calcd. for C H N O : C, 61.97; H, 3.31; N, 19.71.
11
7 3 2
Anal. Calcd. for C
H NO : C, 63.67; H, 4.52; N, 5.71.
13 11 4
Found: C, 61.98; H, 3.41; N, 19.66.
Found: C, 63.59; H, 4.54; N, 5.62.
Methyl 1,9b-Dihydro-1-methylisoxazolo[4,3-f]quinoline-1-car-
boxylate 3-oxide (4d).
Ethyl 2-Nitro-1-naphthaleneacetate (5b).
This compound was obtained as colorless needles (1.74 g,
67%), mp 88-90° (diethyl ether-petroleum ether); ir (potassium
This compound was obtained as colorless prisms (2.16 g,
83%), mp 92-93° (diethyl ether-petroleum ether); ir (potassium
-1
1
bromide): ν 1723 (C=O) cm ; H nmr (deuteriochloroform): δ
1.25 (t, J = 7.3 Hz, 3H, CO CH CH ), 4.20 (q, J = 7.3 Hz, 2H,
-1
1
bromide): ν 1747 (C=O) cm ; H nmr (deuteriochloroform): δ
2
2
3
0.92 (s, 3H, 1-Me), 3.81 (s, 3H, CO Me), 4.32 (s, 1H, 9b-H), 6.87
2
CO CH CH ), 4.40 (s, 2H, CH CO Et), 7.63-7.70 (m, 2H, 6' and
2 2 3 2 2
(d, J = 10 Hz, 1H, 4-H), 7.02 (d, J = 10 Hz, 1H, 5-H), 7.28 (dd, J
= 4.5, 8 Hz, 1H, 8-H), 7.81-7.82 (m, 1H, 9-H), 8.59 ppm (dd, J =
7'-H), 7.89-7.97 (m, 3H, 4', 5' and 8'-H), 8.12-8.16 ppm (m, 1H,
+
3'-H); ms: m/z 260 [M+H] .
+
1.5, 4.5 Hz, 1H, 7-H); ms: m/z 261 [M+H] .
Anal. Calcd. for C
H NO : C, 64.86; H, 5.05; N, 5.40.
14 13 4
Anal. Calcd. for C
H N O : C, 60.00; H, 4.65; N, 10.76.
Found: C, 64.87; H, 5.10; N, 5.35.
13 12 2 4
Found: C, 60.03; H, 4.71; N, 10.57.
2-Nitro-1-naphthaleneacetonitrile (5c) [34].
Ethyl 1,9b-Dihydro-1-methylisoxazolo[4,3-f]quinoline-1-car-
boxylate 3-oxide (4e).
This compound was obtained as colorless needless (0.81 g,
38%), mp 153-155° (acetone-petroleum ether); ir (potassium bro-
-1 1
This compound was obtained as pale orange oil (2.47 g, 90%), ir
mide): ν 2255 (C≡N) cm ; H nmr (deuteriochloroform): δ 4.40 (s,
-1
1
(neat): ν 1731 (C=O) cm ; H nmr (deuteriochloroform): δ 0.92
(s, 3H, 1-Me), 1.30 (t, J = 7.3 Hz, 3H, CO CH CH ), 4.26 and 4.27
2H, CH CN), 7.73-7.82 (m, 2H, 6' and 7'-H), 7.97-8.00 (m, 3H, 4',
2
+
5' and 8'-H), 8.21-8.23 ppm (m, 1H, 3'-H); ms: m/z 213 [M+H] .
2
2
3
(q, J = 7.3 Hz, 2H, CO CH CH ), 4.31 (s, 1H, 9b-H), 6.87 and
Anal. Calcd. for C H N O : C, 67.92; H, 3.80; N, 13.20.
2
2
3
12
8 2 2
6.88 (d, J = 10 Hz, 1H, 4-H), 7.02 (d, J = 10 Hz, 1H, 5-H), 7.28 (dd,
J = 4.5, 8 Hz, 1H, 8-H), 7.82 (dd, J = 1.5, 8 Hz, 1H, 9-H), 8.59 ppm
Found: C, 67.99; H, 3.94; N, 13.19.
Methyl 6-Nitro-5-quinolineacetate (6a).
+
(dd, J = 1.5, 4.5 Hz, 1H, 7-H); ms: m/z 275 [M+H] .
Anal. Calcd. for C
H N O : C, 61.31; H, 5.14; N, 10.21.
This compound was obtained as colorless needless (1.63 g, 66%),
14 14 2 4
Found: C, 61.41; H, 5.24; N, 10.14.
mp 118-120° (acetone-petroleum ether); ir (potassium bromide): ν

1056
H. Maruoka and Y. Tomioka
Vol. 40
-1
1
1736 (C=O) cm ; H nmr (deuteriochloroform): δ 3.74 (s, 3H,
CO Me), 4.39 (s, 2H, CH CO Me), 7.60 (dd, J = 4.5, 8.5 Hz, 1H, 3'-
the case of the use of tetrahydrofuran); ir (neat): ν 1732 (C=O)
-1
1
cm ; H nmr (deuteriochloroform): δ 1.26 (t, J = 7.3 Hz, 3H,
CO CH CH ), 4.14 (s, 2H, CH CO Et), 4.19 (q, J = 7.3 Hz, 2H,
2
2
2
H), 8.20 (s, 2H, 7' and 8'-H), 8.48 (dd, J = 1.5, 8.5 Hz, 1H, 4'-H), 9.07
ppm (dd, J = 1.5, 4.5 Hz, 1H, 2'-H); ms: m/z 247 [M+H] .
2
2
3
2
2
+
CO CH CH ), 7.60 (d, J = 8.5 Hz, 1H, 6'-H), 8.43 (dd, J = 2.4,
2 2 3
Anal. Calcd. for C
Found: C, 58.57; H, 4.09; N, 11.37.
H
N O : C, 58.54; H, 4.09; N, 11.38.
8.5 Hz, 1H, 5'-H), 8.94 ppm (d, J = 2.4 Hz, 1H, 3'-H); ms: m/z
255 [M+H] .
12 10
2 4
+
Anal. Calcd. for C
Found: C, 47.21; H, 3.93; N, 10.93.
H N O : C, 47.25; H, 3.97; N, 11.02.
10 10 2 6
Ethyl 6-Nitro-5-quinolineacetate (6b).
This compound was obtained as colorless needles (1.14 g,
44%), mp 148-150° (acetone-petroleum ether); ir (potassium bro-
Methyl α-Methyl-2,4-dinitrobenzeneacetate (7c).
-1
1
mide): ν 1722 (C=O) cm ; H nmr (deuteriochloroform): δ 1.25
(t, J = 7.3 Hz, 3H, CO CH CH ), 4.20 (q, J = 7.3 Hz, 2H,
This compound was obtained as colorless needles (1.17 g,
46%), mp 54-55° (diethyl ether-petroleum ether); ir (potassium
2
2
3
-1
1
CO CH CH ), 4.38 (s, 2H, CH CO Et), 7.60 (dd, J = 4.5, 8.5 Hz,
bromide): ν 1730 (C=O) cm ; H nmr (deuteriochloroform): δ
2
2
3
2
2
1H, 3'-H), 8.20 (s, 2H, 7' and 8'-H), 8.49 (dd, J = 1.5, 8.5 Hz, 1H,
4'-H), 9.07 ppm (dd, J = 1.5, 4.5 Hz, 1H, 2'-H); ms: m/z 261
[M+H] .
1.66 (d, J = 7 Hz, 3H, 3-Me), 3.70 (s, 3H, CO Me), 4.42 (q, J = 7
2
Hz, 1H, 2-H), 7.74 (d, J = 8.5 Hz, 1H, 6'-H), 8.44 (dd, J = 2.4, 8.5
Hz, 1H, 5'-H), 8.78 ppm (d, J = 2.4 Hz, 1H, 3'-H); ms: m/z 255
+
+
Anal. Calcd. for C
H N O : C, 60.00; H, 4.65; N, 10.76.
13 12 2 4
[M+H] .
Found: C, 60.03; H, 4.61; N, 10.76.
Anal. Calcd. for C
H N O : C, 47.25; H, 3.97; N, 11.02.
10 10 2 6
Found: C, 47.22; H, 4.05; N, 10.96.
6-Nitro-5-quinolineacetonitrile (6c) [7].
Ethyl α-Methyl-2,4-dinitrobenzeneacetate (7d).
This compound was obtained as colorless scales (0.89 g, 42%),
mp 168-170° dec (acetone-petroleum ether); ir (potassium bro-
mide): ν 2251 (C≡N) cm ; H nmr (deuteriochloroform): δ 4.41
This compound was obtained as pale yellow needles (0.91 g,
34%), mp 36-37° (diethyl ether-petroleum ether); ir (potassium
-1
1
-1
1
(s, 2H, CH CN), 7.72 (dd, J = 4.5, 8 Hz, 1H, 3'-H), 8.24 (d, J = 9.2
bromide): ν 1732 (C=O) cm ; H nmr (deuteriochloroform): δ
1.21 (t, J = 7.3 Hz, 3H, CO CH CH ), 1.66 (d, J = 7 Hz, 3H,
2
Hz, 1H, 7'-H), 8.30 (d, J = 9.2 Hz, 1H, 8'-H), 8.56-8.59 (m, 1H, 4'-
2
2
3
+
H), 9.15 ppm (dd, J = 1.5, 4.5 Hz, 1H, 2'-H); ms: m/z 214 [M+H] .
3-Me), 4.13-4.18 (m, 2H, CO CH CH ), 4.40 (q, J = 7 Hz, 1H,
2
2
3
Anal. Calcd. for C H N O : C, 61.97; H, 3.31; N, 19.71.
Found: C, 62.07; H, 3.40; N, 19.68.
2-H), 7.74 (d, J = 8.5 Hz, 1H, 6'-H), 8.43 (dd, J = 2.4, 8.5 Hz, 1H,
5'-H), 8.78 ppm (d, J = 2.4 Hz, 1H, 3'-H); ms: m/z 269 [M+H] .
11
7 3 2
+
Anal. Calcd. for C H N O : C, 49.26; H, 4.51; N, 10.44.
Found: C, 49.30; H, 4.54; N, 10.21.
11 12
2 6
General Procedure for the Preparation of VNS Products 7a-e
from m-Dinitrobenzene and Secondary and/or Tertiary
Carbanions.
α-Methyl-2,4-dinitrobenzeneacetonitrile (7e).
To a solution of m-dinitrobenzene (1.68 g, 10 mmoles) and
methyl chloroacetate (3.26 g, 30 mmoles), ethyl chloroacetate
(3.68 g, 30 mmoles), methyl 2-chloropropionate (3.68 g, 30
mmoles), ethyl 2-chloropropionate (4.10 g, 30 mmoles) or
2-chloropropionitrile (2.69 g, 30 mmoles) in N,N-dimethylfor-
mamide (30 ml) was added 60% sodium hydride (1.20 g, 30
mmoles) at –10° (in the case of the preparation of 7a,b) or 0~5°
(in the case of the preparation of 7c-e) with stirring. After the
mixture was stirred at –10° for 4 hours (7a,b) or 0~5° for 4 hours
(7c-e), cold water was added to the reaction mixture. The result-
ing mixture was extracted with chloroform. After work-up as
described for the preparation of VNS products 5a-c and 6a-c,
compounds 7a-e were obtained.
This compound was obtained as pale yellow needles (1.41 g,
64%), mp 108-110° (acetone-petroleum ether); ir (potassium bro-
-1
1
mide): ν 2248 (C≡N) cm ; H nmr (deuteriochloroform): δ 1.77
(d, J = 7 Hz, 3H, 3-Me), 4.85 (q, J = 7 Hz, 1H, 2-H), 8.07 (d, J =
8.5 Hz, 1H, 6'-H), 8.56 (dd, J = 2.4, 8.5 Hz, 1H, 5'-H), 8.90 ppm
+
(d, J = 2.4 Hz, 1H, 3'-H); ms: m/z 222 [M+H] .
Anal. Calcd. for C H N O : C, 48.87; H, 3.19; N, 19.00.
9
7 3 4
Found: C, 48.97; H, 3.33; N, 18.98.
The Preparation of 8a,b and 9 from 3a,b.
To a solution of 3a (1.23 g, 5 mmoles) or 3b (1.30 g, 5
mmoles) and methyl iodide (2.13 g, 15 mmoles, in the case of the
reaction of 3a) or ethyl iodide (2.34 g, 15 mmoles, in the case of
the reaction of 3b) in N,N-dimethylformamide (10 ml) was added
60% sodium hydride (0.20 g, 5 mmoles) with stirring and ice-
cooling. After the mixture was stirred at room temperature
overnight, a saturated aqueous sodium thiosulfate (30 ml) was
added to the reaction mixture with stirring and ice-cooling. The
resulting mixture was extracted with chloroform. The extract was
dried over anhydrous sodium sulfate and concentrated in vacuo.
The residue was purified by column chromatography on silica gel
with chloroform as the eluent to give the same 9 [from 3a: 0.35 g
(36%), from 3b: 0.30 g (30%)]. Further the elution afforded 8a
[from 3a: 0.22 g (19%)] and 8b [from 3b: 0.23 g (19%)].
Methyl 2,4-Dinitrobenzeneacetate (7a).
This compound was obtained as colorless needles (1.09 g,
45%, in the case of the use of N,N-dimethylformamide; 0.56 g,
23%, in the case of the use of tetrahydrofuran), mp 42-44°
(diethyl ether-petroleum ether); ir (potassium bromide): ν 1739
-1
1
(C=O) cm ; H nmr (deuteriochloroform): δ 3.74 (s, 3H,
CO Me), 4.15 (s, 2H, CH CO Me), 7.61 (d, J = 8.5 Hz, 1H, 6'-
2
2
2
H), 8.44 (dd, J = 2.4, 8.5 Hz, 1H, 5'-H), 8.94 ppm (d, J = 2.4 Hz,
+
1H, 3'-H); ms: m/z 241 [M+H] .
Anal. Calcd. for C H N O : C, 45.01; H, 3.36; N, 11.66.
9
8 2 6
Found: C, 44.86; H, 3.32; N, 11.65.
Methyl (E/Z)-2-(2-Hydroxyimino-1-naphthylidene)acetate (8a)
Ethyl 2,4-Dinitrobenzeneacetate (7b).
This compound was obtained as yellow needles, mp 164-166°
This compound was obtained as pale yellow oil (1.53 g, 60%,
in the case of the use of N,N-dimethylformamide; 0.56 g, 22%, in
dec (acetone-petroleum ether); ir (potassium bromide): ν 3261
(OH), 1715 (C=O) cm ; H nmr (deuteriochloroform): δ 3.87 (s,
-1
1

Nov-Dec 2003
Reactions of Nitroarenes with Secondary and Tertiary Carbanions
1057
Wiley-VCH, New York, 2001.
3H, CO Me), 6.74 (d, J = 12.5 Hz, 1H, 3'-H), 7.06 (d, J = 12.5
2
[5] M. Makosza and J. Golin´ ski, J. Org. Chem., 49, 1488 (1984).
[6] M. Makosza and J. Winiarski, J. Org. Chem., 49, 1494 (1984).
[7] M. Makosza, A. Kinowski, W. Danikiewicz and B. Mudryk,
Liebigs Ann. Chem., 69 (1986).
[8] M. Makosza and J. Winiarski, Acc. Chem. Res., 20, 282
(1987).
[9] N. J. Lawrence, J. Liddle, S. M. Bushell and D. A. Jackson, J.
Org. Chem., 67, 457 (2002).
[10] I. Gallardo, G. Guirado and J. Marquet, J. Org. Chem., 67,
2548 (2002).
[11] I. Gallardo, G. Guirado and J. Marquet, Eur. J. Org. Chem.,
251 (2002).
[12] I. Gallardo, G. Guirado and J. Marquet, Eur. J. Org. Chem.,
261 (2002).
[13] M. Makosza and K. Wojciechowski, Heterocycles, 54, 445
(2001).
[14] T. Murashima, K. Nishi, K. Nakamoto, A. Kato, R. Tamai, H.
Uno and N. Ono, Heterocycles, 58, 301 (2002).
[15] K. B. G. Torssell, Nitrile Oxides, Nitrones and Nitronates in
Organic Synthesis, K. B. G. Torssell, ed, VCH Publishers, Inc., New
York, 1988, pp 106-107.
[16] A. T. Nielsen, Nitrones, Nitronates and Nitroxides, S. Patai
and Z. Rappoport, eds, John Wiley & Sons, New York, 1989, pp 82-138.
[17] S. A. Lang, Jr. and Y.-i Lin, Comprehensive Heterocyclic
Chemistry, A. R. Katritzky and C. W. Rees, eds, Pergamon Press, Oxford,
1984, Vol 6, pp 127-130.
Hz, 1H, 4'-H), 7.30-7.39 (m, 4H, 5', 6', 7' and 8'-H), 7.36 (s, 1H,
2-H), 9.36 ppm (br s, 1H, OH); ms: m/z 230 [M+H] .
+
Anal. Calcd. for C
H NO : C, 68.11; H, 4.84; N, 6.11.
13 11 3
Found: C, 68.14; H, 4.94; N, 5.92.
Ethyl (E/Z)-2-(2-Hydroxyimino-1-naphthylidene)acetate (8b)
This compound was obtained as pale orange plates, mp 161-
163° dec (acetone-petroleum ether); ir (potassium bromide): ν
-1
1
3267 (OH), 1712 (C=O) cm ; H nmr (deuteriochloroform): δ
1.36 (t, J = 7.3 Hz, 3H, CO CH CH ), 4.34 (q, J = 7.3 Hz, 2H,
2
2
3
CO CH CH ), 6.73 (d, J = 12.5 Hz, 1H, 3'-H), 7.06 (d, J = 12.5
2
2
3
Hz, 1H, 4'-H), 7.37 (s, 1H, 2-H), 7.30-7.39 (m, 4H, 5', 6', 7' and
+
8'-H), 9.25 ppm (br s, 1H, OH); ms: m/z 244 [M+H] .
Anal. Calcd. for C
H NO : C, 69.12; H, 5.39; N, 5.76.
14 13 3
Found: C, 69.09; H, 5.42; N, 5.63.
2H-Naphth[2,1-c][1,2]oxazin-2-one (9).
This compound was obtained as orange needles, mp 222-224°
dec (acetone-petroleum ether); ir (potassium bromide): ν 1756
-1 1
(C=O), 1655 (C=C) cm ; H nmr (DMSO-d ): δ 6.98 (d, J = 12.2
6
Hz, 1H, 5-H), 7.40 (d, J = 12.2 Hz, 1H, 6-H), 7.69-7.72 (m, 1H,
9-H), 7.82-7.83 (m, 2H, 7 and 8-H), 8.15 (d, J = 7.6 Hz, 1H, 10-
+
H), 8.26 ppm (s, 1H, 1-H); ms: m/z 198 [M+H] .
Anal. Calcd. for C H NO : C, 73.09; H, 3.58; N, 7.10. Found:
12
7
2
[18] B. J. Wakefield and D. J. Wright, Advances in Heterocyclic
Chemistry, A. R. Katritzky and A. J. Boulton, eds, Academic Press, New
York, 1979, Vol 25, pp 203-204.
C, 73.04; H, 3.63; N, 7.00.
The Preparation of 10 from 5a or 5b.
[19] P. Grünanger and P. Vita-Finzi, Isoxazoles Part One, P.
Grünanger and P. Vita-Finzi, eds, John Wiley & Sons, Inc., New York,
1991.
[20] S. V. Eswaran, Isoxazoles Part Two, P. Grünanger, P. Vita-
Finzi and J. E. Dowling, eds, John Wiley & Sons, Inc., New York, 1999.
[21] A. G. Bolt, P. B. Ghosh and M. J. Sleigh, Biochem.
Pharmacol., 23, 1963 (1974).
[22] J. Lauridsen, T. Honoré and P. Krogsgaard-Larsen, J. Med.
Chem., 28, 668 (1985).
[23] R. B. Davis and L. C. Pizzini, J. Org. Chem., 25, 1884 (1960).
[24] M. Ogata, H. Matsumoto and H. Kano¯, Tetrahedron, 25, 5205
(1969).
[25] T. Okamoto, H. Takahashi, H. Takayama, T. Kitagawa and M.
Ikeda, Chem. Pharm. Bull., 17, 140 (1969).
[26] T. V. RajanBabu, G. S. Reddy and T. Fukunaga, J. Am. Chem.
Soc., 107, 5473 (1985).
[27] M. Makosza, W. Danikiewicz and K. Wojciechowski, Liebigs
Ann. Chem., 711 (1987).
A mixture of 5a (1.23 g, 5 mmoles) or 5b (1.30 g, 5 mmoles)
and sodium iodide (3.00 g, 20 mmoles) in N,N-dimethylfor-
mamide (10 ml, in the case of the reaction of 5a) or dimethylsul-
foxide (10 ml, in the case of the reaction of 5b) and water (1 ml)
was refluxed for 8 hours (5a) or 20 hours (5b), and then cold
water was added to the reaction mixture. The resulting mixture
was extracted with chloroform. The extract was dried over anhy-
drous sodium sulfate and concentrated in vacuo. The residue was
purified by column chromatography on silica gel with chloro-
form as the eluent to give 1-methyl-2-nitronaphthalene (10) [32]
as yellow needles [from 5a: 0.68 g (73%), from 5b: 0.24 g
1
(26%)], mp 57-59° (diethyl ether-petroleum ether); H nmr (deu-
teriochloroform): δ 2.83 (s, 3H, 1-Me), 7.63-7.67 (m, 2H, 6 and
7-H), 7.78 (s, 2H, 4 and 5-H), 7.88-7.90 (m, 1H, 8-H), 8.18-8.20
+
ppm (m, 1H, 3-H); ms: m/z 188 [M+H] .
Anal. Calcd. for C H NO : C, 70.58; H, 4.85; N, 7.48. Found:
11
9
2
[28] B. Mudryk and M. Makosza, Synthesis, 1007 (1988).
[29] N. J. Lawrence, J. Liddle and D. A. Jackson, Tetrahedron
Lett., 36, 8477 (1995).
[30] M. Cervera and J. Marquet, Tetrahedron Lett., 37, 7591
(1996).
C, 70.61; H, 4.90; N, 7.35.
REFERENCES AND NOTES
[1] H. Feuer, The Chemistry of the Nitro and Nitroso Groups
(Part 1 and 2), H. Feuer, ed, John Wiley & Sons Inc., New York,
1969/1970.
[2] A. G. M. Barrett and G. G. Graboski, Chem. Rev., 86, 751
(1986).
[31] I. Lebars, R. Goumont, J.-C. Blazejewski and C. Wakselman,
Synth. Commun., 30, 3161 (2000).
[32] M. Gurjar, D. S. Reddy, A. Murugaiah and S. Murugaiah,
Synthesis, 1659 (2000).
[33] R. D. Topsom and J. Vaughan, J. Chem. Soc., 2842 (1957).
[34] S. Ostrowski, R. J. Moritz and B. Mudryk, Monatshefte für
Chemie, 126, 447 (1995).
[3] G. Rosini and R. Ballini, Synthesis, 833 (1988).
[4] N. Ono, The Nitro Group in Organic Synthesis, N. Ono, ed,