GENERATION OF ELECTROPHILIC IODINE
879
0.25 m thick). UV spectra were recorded on
spectrometer Uvicon-943.
iodinating reagent prepared as described above. The
reaction mixture was maintained for 1.5 h at 20 C
and then poured into 50 ml of 10% sodium sulfite
solution, the separated precipitate was filtered off,
washed with 10% sodium carbonate solution, and
dried. We obtained 0.197 g (98%) of compound VI,
colorless crystals, mp 199 200 C (from AcOH);
204 205 C (from hexane) [14].
Compounds obtained were identified by com-
parison of analytical and physicochemical character-
istics with those of authentic samples prepared by
known methods.
Iodine monochloride and silver trifluoroacetate
were prepared as in [21, 22].
Protodeiodination of 3-iodocarbazole (V). A solu-
tion of 3-iodocarbazole (0.293 g, 1 mmol) in 10 ml
of acetic acid and 0.44 ml (15 mmol) of 96% sulfuric
acid was stirred for 6 h at 20 C. Then the reaction
mixture was poured into 50 ml of 10% sodium sulfite
solution, the solid precipitate was filtered off, washed
with 10% sodium carbonate solution till neutral
washings, and dried. The obtained solid according to
GC-MS data was a mixture of carbazole (3.0%),
1-iodocabazole (9.8%), 3-iodocarbazole (V) (22.9%),
3,6-diiodocarbazole (45.5%), 1,6-diiodocarbazole
(13.9%), 1,3,6-triiodocarbazole (2.6%).
Spectral and analytical results were obtained in the
Analytical Center for General Use of Siberian
Division, Russian Academy of Science (grant of the
Russian
Foundation
for
Basic
Research
no. 00-03-40135).
Anthracene iodination with CF3COOAg ICl
reagent. To a solution of iodine monochloride
(0.2759 g, 1.7 mmol) in 6.5 ml of acetonitrile was
added a solution of silver trifluoroacetate (0.575 g,
2.6 mmol) in 3 ml of acetonitrile. The suspension
obtained was stirred for 1 h at 20 C, the precipitate
of AgCl was filtered off to obtain a dark-brown solu-
tion of iodinating reagent stable for a long time.
To a solution of anthracene (0.0768 g, 0.425 mmol)
in 33 ml of acetonitrile was added at stirring within
20 min the prepared reagent solution. The reaction
mixture was maintained for 1 h at 20 C and then
poured into 50 ml of 10% sodium sulfite solution.
The reaction products were extracted into chloroform,
dried with Na2SO4, the solvent was distilled off to
give 0.13 g of a mixture of 9-iodoanthracene and
9,10-anthraquinone. The mixture was separated by
column chromatography on silica gel L 40/100, eluent
hexane, column 15 1 cm. We obtained 0.22 g (17%)
of 9-iodoanthracene (III), yellow crystals, mp 80
82 C (82 83 C [5]), and 0.053 g (60%) of
9,10-anthraquinone, yellow crystals, mp 283 286 C
(286 C [23]).
The study was carried out under financial support
of the Russian Foundation of basic Research (grant
no. 00-03-32812).
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3-Iodocarbazole (V). To a solution of carbazole
(0.0724 g, 0.434 mmol) in 10 ml of acetonitrile
within 25 min was added at stirring 4.9 ml of iodinat-
ing reagent prepared as described under the previous
experiment. The reaction mixture was maintained for
1.5 h at 20 C and then poured into 50 ml of 10%
sodium sulfite solution, the separated precipitate was
filtered off, washed with 10% sodium carbonate
solution, and dried. We obtained 0.104 g (82%) of
compound V, colorless crystals, mp 193 195 C
(from AcOH); 195 196 C (from hexane) [14].
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3.6-Diiodocarbazole (VI). To a solution of carb-
azole (0.081 g, 0.48 mmol) in 15 ml of acetonitrile
within 30 min was added at stirring 10.6 ml of
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 39 No. 6 2003