2,4,6,8-tetraiodo-2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-dione as a mild and convenient reagent for iodination of aromatic compounds

Article abstract of DOI:10.1023/A:1015047916151

2,4,6,8-Tetraiodo-2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-dione (tetraiodoglycoluril) is a convenient reagent for preparative iodination of benzene, alkylbenzenes, polycyclic hydrocarbons, aromatic amines, and phenol ethers in organic solvents under mild conditions.

Full text of DOI:10.1023/A:1015047916151

Russian Chemical Bulletin, International Edition, Vol. 50, No. 12, pp. 2411—2415, December, 2001
2411
2,4,6,8-Tetraiodo-2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-dione
as a mild and convenient reagent for iodination of aromatic compounds
V. K. Chaikovski,a V. D. Filimonov,a« A. Yu. Yagovkin,a and V. D. Ogorodnikovb
àTomsk Polytechnical University,
30 prosp. Lenina, 634004 Tomsk, Russian Federation.
Fax: +7 (382 2) 41 5235. E-mail: filim@org.chtd.tpu.edu.ru
bInstitute of Petroleum Chemistry, Siberian Branch of the Russian Academy of Sciences,
3 prosp. Akademicheskii, 634021 Tomsk, Russian Federation
2,4,6,8-Tetraiodo-2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-dione (tetraiodoglycoluril) is
a convenient reagent for preparative iodination of benzene, alkylbenzenes, polycyclic
hydrocarbons, aromatic amines, and phenol ethers in organic solvents under mild conditions.
Key words: iodination, aromatic compounds, tetraiodoglycoluril.
Recently,1 we have reported the successful use of
2,4,6,8-tetraiodo-2,4,6,8-tetraazabicyclo[3.3.0]octane-
3,7-dione (tetraiodoglycoluril, TIG) in 90% sulfuric acid
for iodination of deactivated aromatic compounds. To-
gether with the superelectrophilic reagent (the reagent
"I+") generated in H2SO4 upon the reaction of iodine
chloride with silver sulfate,2,3 the TIG—H2SO4 system
can be regarded as one of the most powerful reagents
able to iodinate deactivated aromatic compounds. For
example, nitrobenzene is converted1 into m-iodonitro-
benzene in 75% yield over a period of 1.5 h at 0 °C.
However, the use of concentrated H2SO4 as the medium
limits the scope of application of TIG in the case of
activated arenes due to side processes such as protona-
tion, resinification, sulfonation, etc. For example, our
experiments have shown that the use of TIG in H2SO4
for iodination of alkylbenzenes, aromatic amines, and
polycyclic hydrocarbons is faced with serious problems
of product isolation.
after 5.5 h the yield of iododurene 1b was only 24%. The
use of trifluoroacetic acid instead of acetic acid, also in
the absence of H2SO4, increased substantially the reac-
tion rate. In this case, the precipitate did appear after
1—2 min, but the product 1b formed in a relatively high
yield (64%) contained impurities that markedly de-
creased its melting point. Since H2SO4 is virtually in-
soluble in CCl4 or CHCl3, the experiments in these
solvents were carried out using CF3COOH. The yield of
crude iododurene 1b was 62—69%. According to TLC,
the product was contaminated by the starting durene 1à
and diiododurene 1ñ.
It is important that only the use of CF3COOH
allows one to isolate unsubstituted 2,4,6,8-tetraazabi-
cyclo[3.3.0]octane-3,7-dione (glycoluril), which precipi-
tates after dilution of the reaction mixture with water
and can be recovered in an almost quantitative yield by
filtration (Scheme 1).
The purpose of this work is to study the iodination
capacity of TIG in organic solvents.
Scheme 1
O
Results and Discussion
Me
Me
Me
Me
N
N
N
N
I
I
I
I
Solvent
+
The efficacy of the reaction in various solvents was
studied in relation to 1,2,4,5-tetramethylbenzene (durene)
(1à). It was shown that in aprotic solvents at ∼20 °C,
iodination of arenes by TIG was very slow but the
addition of concentrated H2SO4 or CF3COOH mark-
edly accelerated the reaction
CF3COOH
1a
O
TIG
O
I
In all experiments, the acid was added to a solution
of the substrate and TIG (method À) and the reaction
proceeded rather fast in most solvents. In methanol,
ethanol, acetic acid, or acetonitrile, precipitation of
iododurene 1b is usually observed 1—2 min after the
addition of the acid, its yield being 60—77%. In acetic
acid, the reaction occurred without H2SO4 but even
Me
Me
Me
HN
NH
NH
+
HN
Me
1b
O
Glycoluril
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2302—2306, December, 2001.
1066-5285/01/5012-2411 $25.00 © 2001 Plenum Publishing Corporation

2412
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 12, December, 2001
Chaikovski et al.
When the reaction is carried out in H2SO4,1 or when
H2SO4 is added to the reaction mixture in a solvent, the
glycoluril formed passes during the workup to the aque-
ous phase as the sulfate and can be isolated upon
neutralization.
tained by using 1 mmol of TIG per mmol of sub-
strate 4à.
Some polycyclic aromatic hydrocarbons can be iodi-
nated quite successfully using TIG in dioxane. It is
known that iodination of this type of compounds is often
faced with problems related to the possibility of one-
electron transfer12 and generation of radical ions, giving
rise to side products. It is also known that polycyclic
hydrocarbons react with iodine to give charge transfer
complexes, which inhibit the iodination process. In
some cases, this can be avoided by adding small amounts
of n-electron-donating compounds (dioxane, water,
THF, DMF).8,13
In the dioxane—H2SO4 system, TIG readily iodi-
nates biphenyl (5à), p-terphenyl (6à), and fluorene (7à),
as well as naphthalene (8à) and pyrene (9à) (see Table 1).
In all cases, except for naphthalene (8à), which was
converted into 1-iodonaphthalene (8b), much better
results were attained in the synthesis of diiodinated
derivatives: 4,4´-diiodobiphenyl (5b), 4,4´-diiodo-p-
Dioxane, exhibiting a high solubilizing capacity with
respect to both the starting alkylbenzenes and iodination
products, proved to be the solvent of choice for the
introduction of one, two, or three iodine atoms in the
substrates (S) and their complete conversion; the ratios
[S] : [TIG] being 4 : 1, 2 : 1, and ∼1.3 : 1, respectively.
In dioxane, 1,4-diiododurene (1c) was obtained as readily
as monoiododurene 1b (Table 1). Similarly, p- and
m-xylenes (2a and 3à) are easily converted into mono-
and disubstitution products, namely, 1-iodo-2,5-di-
methylbenzene (2b), 1,4-diiodo-2,5-dimethylbenzene
(2ñ), 1-iodo-2,4-dimethylbenzene (3b), and 1,5-diiodo-
2,4-dimethylbenzene (3ñ). Mesitylene (4à) gives mono-,
di-, and triiodomesitylenes (4b, 4ñ, and 4d, respectively)
in good yields. The last-mentioned product can be ob-
Table 1. Iodination of aromatic compounds with tetraiodoglycoluril in organic solvents
Substrate
Me- Solvent
thod
T
τ
Product
Yield
(%)
M.p./°C (solvent)
or [b.p./°C]*
/°C /min
Experiment
Published data
Durene (1a)
A
A
Dioxane
Dioxane
20
20
15
20
15
30
Iododurene (1b)
Diiododurene (1c)
1-Iodo-2,5-dimethylbenzene (2b) 65
74
75
78—79 (EtOH)
138—139 (EtOH)
[227—230]
78—794
1394
p-Xylene (2a)
[230]5
1,4-Diodo-2,5-dimethyl-
53
101—102 (EtOH)
101—1026
benzene (2c)
1-Iodo-2,4-dimethylbenzene (3b) 67
1,5-Diiodo-2,4-dimethyl-
benzene (3c)
m-Xylene (3a)
Mesitylene (4a)
A
A
Dioxane
Dioxane
20
20
15
30
[229—232]
70—71 (EtOH)
[232]5
70—716
45
15
20
30
20
20
20
30
20
30
Iodomesitylene (4b)
63
72
51
85
80
75
52
30 (MeOH)
73—74 (EtOH)
207—208 (DMF)
203—204 (PrOH)
305—307 (toluene)
208—209 (toluene)
[302—305]
306
74—756
207—2096
2044
Diiodomesitylene (4c)
Triodomesitylene (4d)
4,4´-Diiododiphenyl (5b)
4,4´-Diiodoterphenyl (6b)
2,7-Diiodofluorene (7b)
1-Iodonaphthalene (8b)
1,6-Diiodopyrene (9b)
9-Iodoanthracene (10b)
Biphenyl (5a)
Terphenyl (6a)
Fluorene (7a)
Naphthalene (8a)
Pyrene (9a)
A
A
A
A
A
Á
Dioxane
Dioxane
Dioxane
Dioxane
Dioxane
20
20
20
20
20
305—3077
2104
[305]5
15 261—263 (chlorobenzene) 263—2648
Anthracene (10a)
Benzene** 20
25
78—80
(benzene—MeOH, 1 : 2)
250—252 (toluene)
[185—188]
78—809
Chloroform** 20
30
20
20
10
10
9,10-Diiodoanthracene (10c)
Iodobenzene (11b)
Iodobenzene (11b)
4-Iodoaniline (12b)
4,4´-Diiododiphenyl-
amine (13b)
4-Iodoacetanilide (14b)
2-Iodo-4-nitroaniline (15b)
17
56
44
52
51
254—25510
[186—187.5]4
[186—187.5]4
67—685
125—12611
(80% EtOH)
183—1845
1155
Benzene (11a)
A
Dioxane
Benzene** 20
Ethanol
Ethanol
20
[185—188]
67—68 (hexane)
122—124
Aniline (12a)
Diphenyl-
amine (13a)
Acetanilide (14a)
p-Nitro-
Á
Á
0
0
Á
Á
Ethanol
Ethanol
20
20
20
15
67
71
183—184 (EtOH)
114—115 (PriOH)
aniline (15a)
Anisole (16a)
Diphenyl
ether (17a)
Dibenzo-
Á
Á
Ethanol
Ethanol
20
20
10
10
4-Iodoanisole (16b)
4,4´-Diiododiphenyl
ether (17b)
73
38
51—52 (MeOH)
138—139 (EtOH)
51—525
1404
A
Acetic
acid
20
10
3,6-Diiododibenzofuran (18b)
36
172—173 (EtOH)
172—1734
furan (18a)
* Under a pressure of 760 Torr.
** CF3COOH was used as the catalyst.

Iodination of aromatic compounds
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 12, December, 2001 2413
terphenyl (6b), and 2,7-diiodofluorene (7b). The at-
tempts at monoiodination (molar ratio [S] : [TIG] =
4 : 1) resulted in mixtures of mono- and diiodo-substi-
tuted products. According to TLC, pyrene 9à gave a
mixture of two diiodopyrene isomers, presumably,8
1,6- and 1,8-disubstituted ones, in 82% yield. By recrys-
tallization of this mixture from chlorobenzene, indi-
vidual 1,6-diiodopyrene (9b) was isolated (15%).
traces) and di-, tri-, and tetraiodobenzenes was obtained
over the same period of time. From this mixture, 1,4-di-
iodobenzene (11ñ) (yield 24%) and 1,2,4,5-tetra-
iodobenzene (11d) (yield 3%) were isolated. Under the
same conditions but using CF3COOH as the catalyst,
only iodobenzene 11b was obtained in a yield of 44%
(see Table 1). Polyiodination of benzene did not take
place in this case.
The iodination of anthracene (10à) is known to be
especially difficult as this substrate not only forms non-
polar complexes with iodine, which hamper iodination,
but is also oxidized rather easily to give anthraquinone.14
The reaction with iodine chloride in organic solvents
proceeds as selective chlorination instead of iodina-
tion.12 Therefore, iodoanthracenes are usually prepared
by substitution of iodine for the bromine atoms in
bromoanthracenes.10,15 Direct synthesis of 9-iodo-
anthracene (10b) was performed by treatment of an-
thracene with iodine in benzene in the presence of CuII
salts on alumina as the catalyst.9
The efficiency of TIG as a mild iodination reagent is
confirmed by the results of experiments on iodination of
aromatic amines: aniline (12à), diphenylamine (13à),
acetanilide (14à), and p-nitroaniline (15à) in ethanol
(see Table 1). Since aromatic amines are highly prone to
oxidation, the addition of TIG in two to four portions
proved more efficient (method B) (see Table 1).
4-Iodoaniline (12b) and 4,4´-diiododiphenylamine (13b)
were prepared in quite satisfactory yields at 0 °C. Simi-
larly, but at ∼20 °C, less active arylamines 14à and 15à
underwent iodination to give 4-iodoacetanilide (14b)
and 2-iodo-4-nitroaniline (15b), respectively.
In attempts to iodinate anthracene (10à) with TIG
in dioxane, ethanol, or 80% acetic acid in the presence
of H2SO4 or CF3COOH, we detected only traces of
9-iodoanthracene (10b). In CF3COOH, iodination of
compound 10à did not take place.
Method B is also preferred for iodination of anisole
(16à) and diphenyl ether (17à) in ethanol (see Table 1)
and provides the possibility of preparing 4-iodoanisole
(16b) and 4,4´-diiododiphenyl ether (17b). In the case
of dibenzofuran (18à), method B was inefficient. 3,6-Di-
iododibenzofuran (18b) was prepared in a relatively low
yield (29%) in acetic acid. By using method À, the yield
of compound 18b was increased to 36% (see Table 1).
Study of the mechanism of iodination by TIG was
beyond the scope of this work; nevertheless, we tried to
answer a key question significant for the understanding
of the reaction mechanism, namely, whether iodination
occurs upon direct transfer of iodine from the TIG
molecule to the substrate, or TIG acts only as the source
for the formation of some electrophilic iodine species in
the solution. The latter type of transformation takes
place, for example, in the case of N-iodosuccinimide
(rather close analog of TIG); in trifluoromethane-
sulfonic acid, this gives the solvated iodonium cation
With benzene (11a) as the solvent, quite an unex-
pected result was obtained. At 20 °C with the H2SO4
additive, only did the solvent 11a undergo iodination.
Iodobenzene (11b), p-diiodobenzene (11c), and the start-
ing anthracene (10à) were detected in the reaction
mixture by TLC. When H2SO4 was replaced by
CF3COOH and TIG was added in three portions, com-
plete conversion of anthracene 10à in benzene was
reached over a period of 30 min. Monoiodoanthracene
10b was isolated from the reaction mixture in 25% yield,
no iodobenzene was detected by chromatography.
Direct synthesis of 9,10-diiodoanthracene (10ñ) has
been mentioned (without indication of the yields or
characteristics) in a patent,16 in which iodination of
polycyclic arenes with iodine in the presence of ammo-
nium persulfate was proposed. Our attempts to repro-
duce these results failed. However, we found that diiodide
10ñ can be isolated in 11% yield upon treatment of
anthracene with 4 equiv. of TIG in benzene in the
presence of CF3COOH. According to TLC, iodobenzene,
anthraquinone, and some unidentified products were
also present in the reaction mixture. Somewhat better
results in the synthesis of diiodide 10c were attained in
CHCl3 (17%) (see Table 1).
– +
CF3SO2O I , which acts directly as the iodinating
agent.17
To solve this problem tentatively, we studied the
13C NMR spectra of TIG and glycoluril in D2SO4. It
was found that as soon as 2—3 min after dissolution of
TIG in concentrated D2SO4 at 20 °C the spectrum
exhibited signals for the CO and CH groups at δ 165.9
and 71.5, which coincide completely with the corre-
sponding signals in the spectrum of glycoluril in D2SO4.
Dehalogenation of TIG occured rapidly, and no inter-
mediates containing one to three iodine atoms could be
detected in the spectra. However, in the 13C NMR
spectrum of a solution of TIG in D2SO4, no signal at
δ 163.3 corresponding to the carbonyl group of proto-
nated urea can be found even two days after dissolution;
this suggests that glycoluril itself does not decompose
under these conditions.
It is noteworthy that benzene 11à itself can be
iodinated rather successfully in dioxane with H2SO4 as
the additive to give iodobenzene 11b (56%) (see Table 1);
however, further iodination of product 11b does not
occur even when it is kept with 1 equiv. of TIG in
dioxane for 0.5 h at 20 °C. However, treatment of
solvent 11à with TIG (30-fold molar excess of benzene
with respect to TIG) in the presence of H2SO4 gave a
solid product containing (TLC) monoiodobenzene (11b,
Thus, TIG, like N-iodosuccinimide,17 functions as a
source of I+ in the reaction mixture. Presumably, elimi-

2414
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 12, December, 2001
Chaikovski et al.
substrate (10 mmol) in 15 mL of the corresponding solvent,
and 3 mL of concentrated H2SO4 was added with cooling. The
mixture was stirred at 20 °C for the period of time indicated in
Table 1. In the synthesis of di- or triiodo-substituted products
(1c—3c, 4c,d, 5b—7b, 9b, and 18b), the amount of the
substrate taken was decreased two- or three-fold. The reaction
mixture was diluted with 100 mL of water. Liquid products 2b,
3b, and 11b were extracted with chloroform, the extracts were
dried with CaCl2 and concentrated, and the residue was
distilled. Solid compounds were filtered off, dried, and, if
required, crystallized from the appropriate solvent. Product 8b
was extracted with hexane, the extract was dried with CaCl2,
filtered through a layer of Al2O3, and distilled in vacuo. To
isolate diiodopyrene 9b, the reaction mixture was chromato-
graphed on a short column with Al2O3 using hexane as the
eluent. Three recrystallizations from chlorobenzene gave indi-
vidual 1,6-diiodopyrene 9b.
nation of iodine is a stepwise process including protona-
tion in each of the four steps. One step is shown in
Scheme 2.
Scheme 2
O
OH
+
N
N
N
N
N
N
N
I
I
I
I
I
I
I
I
H2SO4
–
HSO4
N
O
O
9-Iodoanthracene (10b) (method B). CF3COOH (3 mL)
was added to a solution of compound 10à (0.89 g, 5 mmol) in
20 mL of benzene. At 20 °C, TIG (1.62 g, 2.5 mmol) was
added in three portions over a period of 2—3 min, and the
mixture was stirred for 30 min at 20 °C. A 3% solution of
Na2SO3 (50 mL) was added to the reaction mixture, and the
glycoluril that precipitated (0.35 g) was filtered off. The ben-
zene layer was separated and dried with CaCl2, the solvent was
evaporated in vacuo, and the residue was chromatographed on
a short column with Al2O3 using hexane as the eluent. After
removal of hexane in vacuo, iodide 10à was crystallized from a
methanol—benzene mixture (2 : 1).
9,10-Diiodoanthracene (10ñ) (method B). CF3COOH
(3 mL) was added to a solution of compound 10à (0.45 g,
2.5 mmol) in 20 mL of CHCl3. At 20 °C, TIG (1.62 g,
2.5 mmol) was added in four portions over a period of 30 min.
Chloroform (10 mL) and a 3% solution of Na2SO3 (50 mL)
were added to the reaction mixture. The precipitate of glycoluril
(0.34 g) was filtered off. The chloroform layer was separated,
dried with CaCl2, the solvent was evaporated in vacuo, and the
residue was chromatographed on a short column with Al2O3
using hexane as the eluent.
Reaction of benzene (11à) with TIG. TIG (1.62 g, 2.5 mmol)
and H2SO4 (4 mL) were added to 27 mL of benzene (11à), the
mixture was stirred for 30 min at 20 °C and washed with water,
the benzene layer was separated and dried with CaCl2. Evapo-
ration of benzene in vacuo gave 1.61 g of a solid. This product
was extracted into 5 mL of boiling EtOH. Cooling of the
extract gave 1,4-diiodobenzene (11ñ), yield 0.79 g (24%), m.p.
127—128 °C (cf. Ref. 4: m.p. 130—131 °C). The residue
insoluble in boiling EtOH was 1,2,4,5-tetraiodobenzene (11d),
yield 0.17 g (3%), m.p. 250—252 °C (cf. Ref. 16: m.p. 254 °C).
When CF3COOH was used, iodobenzene (11b) was obtained
as the only product.
Iodination of amines (12à—15à) and phenol ethers (16à,
17à) (method B). Sulfuric acid (1.5 mL) was added to a
solution of substrate 13à—17à (5 mmol) (or 10 mmol of
aniline 12à) in 15 mL of EtOH, and TIG (1.62 g, 2.5 mmol)
was added in three portions over a period of 2—3 min.
Iodination of compounds 12à and 13à was carried out at 0 °C;
other compounds were iodinated at 20 °C. After completion of
the reaction, a 5% solution of NaOH (30 mL) was added, and
the products were filtered off, washed with water, dried, and
crystallized. To isolate compounds 16b and 17b, the reaction
mixture was diluted with 50 mL of 3% Na2SO3 and the
products were filtered off, dried, and crystallized.
O
I
N
N
N H
– +
+
HOSO2O I
I
N
I
O
It should be noted that in the absence of an acid, a
solution of TIG in, for example, DMSO-d6 remains
unchanged for two days at 25 °C.
The form of existence of iodine-containing electro-
philic species in solutions of TIG in sulfuric and
trifluoroacetic acids can be judged resorting to published
data.17,18 In all probability, in sulfuric acid, they are
solvated forms HOSO2O I and/or (I+–O)2SO2, and in
trifluoroacetic acid, this is CF3COO I .
– +
– +
It is also noteworthy that, unlike iodination with the
TIG—H2SO4 system where the maximum conversion of
the substrate requires 2 equiv. of TIG for the introduc-
tion of one iodine atom,1 iodination in organic solvents
takes normally one equivalent of the reagent with re-
spect to the substrate (0.25 moles of TIG per mole of
the substrate) irrespective of the nature of the acid.
Thus, TIG is one of few iodinating reagents able to
iodinate under mild conditions a variety of aromatic
compounds ranging from highly deactivated to activated
and polycyclic ones. However, the iodination conditions
(the solvent, the type of acid catalyst, the order of
addition of the reactants) are specific for each type of
aromatic substrates.
Experimental
The reactions were monitored and the purity of com-
pounds was checked by TLC on Silufol UV-254 plates in
hexane (or in benzene, for compounds 12à,b—15à,b); sub-
stances were visualized in the UV light. 13C NMR spectra were
recorded on a Tesla BS-587 spectrometer using D2O as the
external standard. Tetraiodoglycoluril was prepared by a previ-
ously published procedure.19
This work was supported by the Russian Foundation
for Basic Research (Project No. 00-03-32812à).
Iodination of compounds 1à—9à, 11à, and 18à (method A).
TIG (1.62 g, 2.5 mmol) was added to a solution of aromatic

Iodination of aromatic compounds
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 12, December, 2001 2415
10. F. B. Duerr, Y.-S. Chang, and W. A. Czarnik, J. Org.
Chem., 1988, 53, 2120.
References
11. M. I. Bardamova, Z. P. Trotsenko, and I. L. Kotlyarevskii,
Izv. Akad. Nauk SSSR, Ser. Khim., 1982, 1184 [Bull. Acad.
Sci. USSR, Div. Chem. Sci., 1982, 31 (Engl. Transl.)].
12. D. E. Turner, R. F. O´Malley, J. Sardella, L. S. Barinelli,
and P. Kaul, J. Org. Chem., 1994, 59, 7335.
13. V. K. Chaikovski, V. T. Novikov, A. N. Novikov, and
F. Sh. Garifullina, Zh. Obshch. Khim., 1985, 55, 893
[J. Gen. Chem. USSR, 1985, 55 (Engl. Transl.)].
14. E. Klar. Politsiklicheskie uglevodorody [Polycyclic Hydrocar-
bons], Khimiya, Moscow, 1971, 1, 290 (in Russian).
15. H. Suzuki, A. Kondo, M. Inouye, and T. Ogawa, Synthesis,
1986, 121.
16. I. M. Trevor, I. P. Szabo, and R. T. Sam, US Pat.,
4240987.
17. G. A. Olah, Qi. W. Wang, G. Sandford, and G. K. S.
Prakash, J. Org. Chem., 1993, 58, 3194.
18. P. Lulinski and L. Skulski, Bull. Chem. Soc. Jpn., 2000,
73, 951.
19. A. Yu. Yagovkin, A. A. Bakibaev, and E. L. Bystritskii,
Khimiya Geterotsikl. soedinenii, 1995, 1695 [Chem.
Heterocycl. Compd., 1995 (Engl. Transl.)].
1. V. K. Chaikovski, V. D. Filimonov, A. Y. Yagovkin, and
T. S. Kharlova, Tetrahedron Lett., 2000, 41, 9101.
2. V. K. Chaikovski, T. S. Kharlova, V. D. Filimonov, and
T. A. Saryucheva, Synthesis, 1999, 748.
3. V. K. Chaikovski, T. S. Kharlova, and V. D. Filimonov,
Izv. Akad. Nauk, Ser. Khim., 1999, 1303 [Russ. Chem.
Bull., 1999, 48, 1291 (Engl. Transl.)].
4. Sintezy iodistykh organicheskikh soedinenii [Syntheses of Or-
ganic Iodine Compounds], Eds. L. M. Yagupol´skii, A. N.
Novikov, and E. B. Merkushev, Izd-vo Tomsk Gos. Un-ta,
Tomsk, 1976, 25 (in Russian).
5. Dictonary of Organic Compounds, Eds. I. Heibron and
H. M. Bunbury, London, 1946, 1, 2.
6. E. B. Merkushev, Preparativnye sintezy iodaromaticheskikh
soedinenii [Preparative Syntheses of Iodoaromatic Com-
pounds], Izd-vo Tomsk. Gos. Un-ta, Tomsk, 1985, 72 (in
Russian).
7. E. B. Merkushev and N. D. Yudina, Zh. Org. Khimii, 1981,
17, 2598 [J. Org. Chem. USSR, 1981, 17 (Engl. Transl.)].
8. V. K. Chaikovski, and A. N. Novikov, Zh. Org. Khim.,
1984, 20, 1482 [J. Org. Chem. USSR, 1984, 20 (Engl.
Transl.)].
9. M. Kodomari, N. Amanokura, K. Takeuchi, and
S. Yoshitomi, Bull. Chem. Soc. Jpn., 1992, 65, 306.
Received November 4, 2000
in revised form May 10, 2001