PAPER
Arenediazonium o-Benzenedisulfonimides
477
+
MS (EI, 70 eV): m/z (%) = 368 (22) [M – Me] }. All attempts to iso-
Column chromatography and TLC were performed on Merck silica
gel 60 (70–230 mesh ASTM) and GF 254, respectively. Petroleum
late compound 7 failed. The solution was poured into Et
(200 mL, 1:1), the aqueous layer was separated and extracted with
Et O (50 mL). The combined organic extracts were washed with
O (2 × mL) and dried (Na SO ). After removal of the solvent un-
O–H O
2
2
1
ether (PE) refers to the fraction boiling in the range 40–70 °C. H
NMR spectra were recorded on a Bruker Avance 200 spectrometer.
Mass spectra were recorded on an HP 5989B mass-selective detec-
tor connected to an HP 5890 GC cross-linked methyl silicone
capillary column. Room temperature (r.t.) was 20–25 °C. Chro-
matographic solvent, yields, physical and spectral data (MS) of the
2
H
2
2
4
der reduced pressure, the crude residue was the virtually pure title
1
compound 4e (GC, GC-MS, TLC, H NMR). The aqueous layer and
aqueous washings were collected and evaporated under reduced
pressure and the black tarry residue was passed through a column of
1
pure (GC, GC-MS, TLC, H NMR) isolated toluenes 4a–m, buty-
larenes 5a–f, 5h, 5n and ethylarenes 11a–f, 11h, 11n are reported in
Table 1 and Table 2.
Dowex 50X8 ion-exchange resin (1.6 g/1 g of product) using H
(~50 mL) as eluent. After removal of H O under reduced pressure,
virtually pure ( H NMR) o-benzenedisulfonimide (8) was recovered
O
2
2
1
Structures of all the products obtained in the course of this research
were confirmed by comparison of their physical (mp or bp) and
spectral data with those reported in the literature or with those of the
commercially available samples (Sigma–Aldrich) of analytical pu-
rity.
2
1
(
1.77 g, 81% yield); mp 192–194 °C (toluene) (Lit. 192–194 °C).
According to the procedure described above, 1e (3.68 g, 10.0 mmol)
was treated with Bu Sn (3). GC, GC-MS, and TLC (PE–Et O, 9:1)
4
2
analyses of the reaction mixture showed 4-nitrobutylbenzene {5e;
+
MS (EI, 70 eV): m/z (%) = 179 (37) [M ]} and nitrobenzene {6e;
Me Sn, Bu Sn, Et B solution (1.0 M in THF), Bu B solution (1.0 M
3
4
4
3
+
MS (EI, 70 eV): m/z (%) = 123 (100) [M ]} as major products be-
sides o-benzenedisulfonylimidotributyltin {7; MS (EI, 70 eV): m/z
in THF), MeB(OH)2, BuB(OH)2, Pd(OAc)2, (Ph P) PdCl ,
3
2
2
Pd(Cl )dppf·CH Cl , and all the anilines, were purchased from Sig-
2
2
2
+
%) = 452 (11) [M – Bu]} as minor product. 5e was obtained (0.74
(
g, 41% yield) by chromatography (PE–Et O, 9:1) of the crude resi-
ma–Aldrich; Dowex 50X8 ion-exchange resin was purchased from
Fluka.
2
due. Formation of the volatile compound 6e was not quantified.
No traces of 5e were detected when the reaction was carried out
with dioxane or MeCN as solvents or with Pd(Cl )dppf as precata-
Arenediazonium o-benzenedisulfonimides 1a–n were prepared as
2
1
described previously. The crude salts were virtually pure and were
used without further crystallization.
2
lyst (0.25 mmol, 0.20 g).
CAUTION! In our laboratory there was no case of sudden decom-
position during the preparation, purification and handling of salts 1.
Nevertheless, it must be borne in mind that all diazonium salts in the
anhydrous state are potentially explosive. Therefore, they must be
carefully stored and handled.
With MeCN: Conducted as above, but using MeCN as solvent.
GC,GC-MS and TLC (PE–Et O, 9:1) analyses of the reaction mix-
ture showed 4e to be formed as the major product, along with traces
2
+
of 4,4¢-dinitrobiphenyl {MS (EI, 70 eV): m/z (%) = 244 (100) [M ]}
and 6e. Pure 4e was obtained (1.20 g, 88%) by chromatography
(
PE–Et O, 9:1) of the crude residue; 8 was also recovered (1.74 g,
2
2
-Methyl-4-nitrobenzenediazonium o-Benzenedisulfonimide
1k)
7
9% yield).
(
Yield: 92%; mp 169–170 °C (dec.) (HCO H).
Details of the reactions and yields of the pure toluenes 4a–m and
butylarenes 5b,5d–f and 5h are listed in Table 1.
2
1
H NMR (200 MHz, CF CO D): d = 2.35 (s, 3 H), 7.41–7.45 (m,
3
2
1
H, Harom), 7.48–8.25 (m, 6 H, Harom).
Reactions of Arenediazonium o-Benzenedisulfonimides 1 with
Trialkylboranes 9 or 10
Synthesis of 4-Nitroethylbenzene (11e); Typical Procedure
1
3
C NMR (50 MHz, CF CO D): d = 18.9, 110.8, 121.5, 126.1,
3
2
1
29.7, 134.9, 135.3, 136.9, 138.1, 148.0.
4
1
-Nitrobenzenediazonium o-benzenedisulfonimide (1e; 3.68 g,
0.0 mmol) was added in one portion with vigorous stirring to Et B
Anal. Calcd for C H N O S : C, 40.84; H, 2.64; N, 14.65; S,
6 2
13
10
4
1
6.77. Found: C, 40.93; H, 2.59; N, 14.62; S, 16.68.
3
(9; 1.0 M in THF, 11 mL) and further THF (4 mL) was added.
Pd(Cl )dppf (0.25 mmol, 0.20 g) was then added in one portion and
stirring was maintained at r.t. for 30 min. The completion of the re-
action was confirmed by the absence of azo-coupling with 2-naph-
thol. GC, GC-MS and TLC (PE–Et O, 9:1) analyses of the reaction
3-Chloro-4-methoxybenzenediazonium o-Benzenedisulfon-
imide (1l)
2
Yield: 99%; mp 113–114 °C (dec.) (HCO H).
2
2
1
H NMR (200 MHz, CF CO D): d = 3.75 (s, 3 H), 6.80–6.82 (m,
3
2
mixture showed 4-nitroethylbenzene {11e; MS (EI, 70 eV): m/z
(
1
H, Harom), 7.02–7.25 (m, 2 H, Harom), 7.58–8.05 (m, 4 H, Harom).
+
%) = 151 (94) [M ]} was formed as the major product, besides
1
3
C NMR (50 MHz, CF CO D): d = 55.9, 115.1, 122.8, 127.8,
3
traces of 6e. The workup described above furnished a crude residue
which was purified by column chromatography (PE–Et O, 9:1) to
give the pure title compound 11e (1.31 g, 87% yield) and recovered
(1.78 g, 82% yield).
2
1
29.8, 130.6, 135.0, 136.9, 138.9, 154.7.
2
Anal. Calcd for C H ClN O S : C, 43.40; H, 2.80; Cl, 9.85; N,
10
13
3
5 2
8
3
.89; S, 17.82. Found: C, 43.36; H, 2.82; Cl, 9.88; N, 3.85; S, 17.86.
After carrying out the reaction with Pd(OAc) (0.25 mmol, 0.05 g),
GC, GC-MS and TLC (PE–Et O, 9:1) analyses of the reaction mix-
ture showed 6e was formed as the sole product. When (Ph P) PdCl
(0.25 mmol, 0.17 g) was used, only a small amount of 11e (0.35 g,
23% yield) was recovered; GC, GC-MS and TLC (PE–Et O, 9:1)
Reactions of Arenediazonium o-Benzenedisulfonimides 1 with
Tetraalkyltins 2 or 3
Synthesis of 4-Nitrotoluene (4e); Typical Procedures
With THF: 4-Nitrobenzenediazonium o-benzenedisulfonimide (1e;
2
3
2
2
2
3
to a solution of Me Sn (2; 1.97 g, 11.0 mmol) in THF (15 mL) at 40
.68 g, 10.0 mmol) was added in one portion with vigorous stirring
analyses of the reaction mixture showed 6e to be the major product.
4
Details of the reactions 1–16 and yields of the pure ethylbenzenes
11a–f, 11h, 11n and butylbenzenes 5a–f, 5h, 5n are listed in
Table 2.
°C. Pd(OAc) (0.25 mmol, 0.05 g) was added in one portion and
2
stirring at 40 °C was maintained for 30 min. Completion of the re-
action was confirmed by the absence of azo-coupling with 2-naph-
thol. GC, GC-MS, and TLC (PE–Et O, 9:1) analyses of the reaction
2
Reactions of 1e with Methylboronic or Butylboronic Acid
mixture showed 4-nitrotoluene {4e; MS (EI, 70 eV): m/z (%) = 137
+
100) [M ]} to be the major product. Furthermore, GC-MS analysis
1
e (3.68 g, 10.0 mmol) was added in one portion with vigorous stir-
ring to a solution of MeB(OH) (0.66 g, 11.0 mmol) or BuB(OH)
(
showed the presence of o-benzenedisulfonylimidotrimethyltin {7;
2
2
(1.12 g, 11.0 mmol) in THF (15 mL). Pd(OAc) (0.25 mmol, 0.05 g)
Synthesis 2008, No. 3, 474–478 © Thieme Stuttgart · New York