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M. Barbero et al.
PAPER
Anal. Calcd for C12H8FN3O4S2 (341.0): C, 42.23; H, 2.36; F, 5.57;
N, 12.32; S, 18.75. Found: C, 42.37; H, 2.36; F, 5.58; N, 12.34; S,
18.84.
Structure of the three isomers was confirmed by comparison with
authentic samples (Aldrich).
When the reaction was carried out in the presence of nitrobenzene
(1.85 g, 15 mmol), a mixture of o-, m- and p-nitrodiphenyl, each
with m/z 199 (M+) in MS in a ratio of 2.4:7.4:1.0, was also obtained.
Structure of the three isomers was confirmed by comparison with
authentic samples (Aldrich).
o-Bromobenzenediazonium o-Benzenedisulfonimide (1m)
Yield: ~100%; dp 142Ð143¡C (dissolved in hot anhyd MeCN and
then precipitated with anhyd Et2O, after cooling).
1H NMR (CF3CO2D): δ = 7.55Ð8.15, 8.35Ð8.60 (2 m, 7:1, 8 H).
Aryl methanesulfonates 3bÐd,fÐh,jÐo,qÐu were prepared accord-
ing to the above procedure (Table, entries 1Ð4, 6Ð8, 10Ð15, and 17Ð
21). Reaction conditions, yields of products 3 and their physical
properties, and yields of recovered 4 are reported in the Table. For
Entries 5, 9, and 16 no reaction had taken place.
Anal. Calcd for C12H8BrN3O4S2 (402.2): C, 35.83; H, 2.00; Br, 19.86;
N, 10.45; S, 15.94. Found: C, 35.93; H, 2.01; Br, 19.77; N, 10.33; S,
16.04.
m-Trifluoromethylbenzenediazonium o-Benzenedisulfonimide
(1s)
Yield: 93%; dp 120Ð121¡C (dissolved in hot anhyd MeCN and then
precipitated with anhyd Et2O, after cooling).
1H NMR (CF3CO2D): δ = 7.62Ð8.02, 8.02Ð8.35, 8.35Ð8.62 (3 m,
o-Methylthiophenyl Methanesulfonate (3h)
Physical, analytical and spectroscopic data are not reported in the
literature.5b
1H NMR (CDCl3): δ = 2.40 (s, 3 H), 3.10 (s, 3 H), 7.00Ð7.30 (m, 4 H).
Anal. Calcd for C8H10O3S2 (218.0): C, 44.04; H, 4.62; S, 29.33.
Found: C, 43.97; H, 4.57; S, 29.32.
5:1:2, 8 H).
Anal. Calcd for C13H8F3N3O4S2 (391.0): C, 39.90; H, 2.06; F, 14.58;
N, 10.74; S, 16.35. Found: C, 39.73; H, 2.01; F, 14.58; N, 10.67; S,
16.46.
m-Bromophenyl Methanesulfonate (3n)
1H NMR (CDCl3): δ = 3.28 (s, 3 H), 7.28Ð7.75 (m, 4 H).
Anal. Calcd for C7H7BrO3S (249.9): C, 33.61; H, 2.82; Br, 31.58;
S, 12.79. Found: C, 33.70; H, 2.79; Br, 31.48; S, 12.75.
p-Trifluoromethylbenzenediazonium o-Benzenedisulfonimide
(1t)
Yield: 92%; dp 105Ð106¡C (dissolved in hot anhyd MeCN and then
precipitated with anhyd Et2O, after cooling).
1H NMR (CF3CO2D): δ = 7.42Ð8.00, 8.20Ð8.60 (2 m, 3 :1, 8 H).
p-Chlorophenyl Trifluoromethanesulfonate (6c);
Typical Procedure
A solution of p-chlorobenzenediazonium o-benzenedisulfonimide
(1l; 1.78 g, 5 mmol) in trifluoromethanesulfonic acid (5; 8 mL) was
heated in an oil bath at 90¡C until a proof of azo coupling reaction
with 2-naphthol was negative (2 h). After a workup identical to that
described above for the preparation of 3a, the pure title compound
was obtained in 76% yield (0.98 g); bp 114¡C/20 Torr (Lit.8 bp
108¡C/25 Torr).
Anal. Calcd for C13H8F3N3O4S2 (391.0): C, 39.90; H, 2.06; F, 14.58;
N, 10.74; S, 16.35. Found: C, 39.80; H, 2.01; F, 14.65; N, 10.64; S,
16.42.
Phenyl Methanesulfonate (3a); Typical Procedure
A solution of benzenediazonium o-benzenedisulfonimide (1a;
1.62 g, 5 mmol) in MeSO3H (2; 5 mL) was stirred and slowly heated
in an oil-bath from r.t. to 60¡C during a period of 1.5 h. This tem-
perature was then maintained for a further 3 h until a proof of azo
coupling reaction with 2-naphthol was negative. After cooling, the
reaction mixture was poured into an ice-cooled mixture of Et2O/
H2O (60 mL, 1:1). The aqueous layer was separated and extracted
again with Et2O (2 × 30 mL). The combined organic extracts were
washed with 5% aq NaHCO3 solution (50 mL) and then with H2O
(50 mL). After drying (Na2SO4) and removal of solvent in vacuo,
the crude residue was column chromatographed, using CHCl3 as
eluent, to afford the pure title compound 3a (0.73 g, 85%); mp 62¡C
(EtOH) (Lit.10 mp 61Ð62¡C); MS: m/z 172 (M+). A small amount of
a byproduct derived from the thermal decomposition of 1a, i.e. O-
phenyl-o-benzenedisulfonimide, was also isolated (0.08 g, 6%); mp
106¡C (CHCl3/petroleum ether) (Lit.14 mp 106¡C); MS: m/z 295
(M+). No traces of the other thermal decomposition product of 1a,
i.e. N-phenyl-o-benzenedisulfonimide, was identified by 13C NMR
analysis of the crude reaction mixture. Bu4NOH (40% aq solution;
3.5 mL) was added to the aqueous solution. A white solid substance
constituted of tetrabutylammonium o-benzenedisulfonimide began
to separate at once. The precipitate was gathered by filtration on a
BŸchner funnel, placed in a chromatographic column containing 40
g of Dowex 50 × 8 ion-exchange resin (Fluka) and eluted with H2O
(300 mL). After removal of H2O in vacuo, virtually pure (NMR) o-
benzenedisulfonimide (4) was recovered in 86% yield (0.94 g): mp
192Ð194¡C (from toluene) (Lit.14 mp 192Ð194¡C).
1H NMR (CDCl3): δ = 7.12, 7.42 (2 d, 1:1, J = 8 Hz).
o-Chlorophenyl Trifluoromethanesulfonate (6a)
Physical, analytical and spectroscopic data are not reported in the
literature.7
1H NMR (CDCl3): δ = 7.08Ð7.58 (m).
Anal. Calcd for C7H4ClF3O3S (260.6): C, 32.26; H, 1.55; Cl, 13.60;
F, 21.87 ; S, 12.30. Found: C, 32.32; H, 1.60; Cl, 13.67; F, 21.95; S,
12.36.
m-Chlorophenyl Trifluoromethanesulfonate (6b)
Physical, analytical and spectroscopic data are not reported in the
literature.7
1H NMR (CDCl3): δ = 6.95Ð7.45 (m).
Anal. Calcd for C7H4ClF3O3S (260.6): C, 32.26; H, 1.55; Cl, 13.60;
F, 21.87 ; S, 12.30. Found: C, 32.20; H, 1.50; Cl, 13.66; F, 21.80; S,
12.25.
Acknowledgement
This work was supported by the National Research Council of Italy
(CNR), Legge 95/95, and by Ministero dellÕUniversitˆ e della
Ricerca ScientiÞca e Tecnologica (MURST).
The reaction was carried out also in the presence of toluene (1.38 g,
15 mmol). In addition to the products obtained above, column chro-
matography of the crude residue afforded a solid substance, which
was the first to be eluted. GC and GC/MS analyses showed the pres-
ence of three products, i.e. o-, m- and p-methyldiphenyl, each with
m/z 168 (M+) in MS in a ratio of 2.4:1.0:1.3; yield:2.6% (0.022 g).
References
(1) For example, see:
(a) Uchida, O.; Tsukase, M. Japanese Patent 08277250, 1996;
Chem. Abstr. 1997, 126, 46962.
Synthesis 1999, No. 1, 90–93 ISSN 0039-7881 © Thieme Stuttgart · New York