1,3-DIIODO-5,5-DIMETHYLHYDANTOIN—AN EFFICIENT REAGENT
1295
the precipitate was filtered off, dried, and recrystal-
lized if necessary. The yields, melting points, solvents
for recrystallization, and reaction times are given in
Table 1.
substrate amount was reduced by half. The progress of
the reaction was monitored by TLC using carbon
tetrachloride (nitro compounds XIII–XV and XXI),
hexane–acetic acid (10:1) (carboxylic acids XVI–
XXVII), or benzene (XVIII–XX) as eluent. When the
reaction was complete, the mixture was poured into
100 ml of an ice–water mixture and treated with
a solution of Na2SO3. Compounds XIIIb–XVb were
extracted into methylene chloride, the extract was
dried over CaCl2, and the solvent was removed.
Compounds XVIb and XVIIb precipitated from the
mixture and were filtered off, dried, and (if necessary)
recrystallized from appropriate solvent (Table 2).
Compound XXb was dissolved in benzene, the solu-
tion was filtered through a layer of silica gel, and the
solvent was distilled off from the filtrate. The yields,
melting points, solvents used for recrystallization, and
reaction times are given in Table 2.
1,4-Diiodo-2,3,5,6-tetramethylbenzene (IIc).
Compound I, 5 mmol (1.9 g), was added to a solution
of 5 mmol (0.67 g) of durene (IIa) in 15 ml of acetic
acid, 2 ml of concentrated sulfuric acid was then added
under stirring and cooling with cold water, and the
mixture was stirred for 30 min at 20°C and diluted
with 30 ml of water. The precipitate was filtered off,
dried, and recrystallized from ethanol. Yield of IIc
1.45 g (75%).
Iodination of compounds VIa–XIIa (general
procedure). Sulfuric acid, 2 ml, was added under
stirring and cooling to a solution of 10 mmol of
compound VIa–XIIa in 15 ml of ethanol, and 5 mmol
(1.9 g) of compound I was then added in 3 portions
over a period of 2–3 min. In the synthesis of di- and
triiodo derivatives, the substrate amount was reduced
twice and thrice, respectively. When the reaction was
complete, the mixture was diluted with 50 ml of a 3%
solution of Na2SO3 (to isolate iodinated products VIb–
VIIIb) or with 40 ml of a 10% solution of NaOH (to
isolate iodinated amines IXb–XIIb and IXc), and the
precipitate was filtered off, washed with water (IXb–
XIIb, IXc), dried, and recrystallized from appropriate
solvent. For other details, yields, and solvents for re-
crystallization, see Table 1.
3-Iodonitrobenzene (XIIIb). Sulfuric acid (90%,
d = 1.825 g/cm3), 15 ml, was cooled to 0–5°C and
added to 5 mmol (1.9 g) of compound I, and the mix-
ture was stirred for 20–30 min at room temperature
until it became homogeneous. The solution was cooled
to 0°C, 5 mmol (0.62 g) of nitrobenzene (XIIIa) was
added, and the mixture was stirred for 60 min at 0°C,
poured into 50 ml of water containing ice, treated with
an aqueous solution of Na2SO3, and extracted with
methylene chloride. The extract was dried over CaCl2,
the solvent was distilled off, and the residue was
recrystallized from ethanol. Yield 0.93 g (75%). The
iodination of XIIIa at 20°C was performed in a similar
way. Yield 0.96 g (77%).
4,4′-Diiododiphenylamine (XIIb). Sulfuric acid,
2 ml, was added under stirring and cooling with
an ice–water mixture to a solution of 0.5 mmol
(0.85 g) of diphenylamine (XIIa) in 15 ml of ethanol,
and 5 mmol (1.9 g) of compound I was then added in
3 portions over a period of 2–3 min. After 10 min,
40 ml of a 10% solution of sodium hydroxide was
added, and the precipitate was filtered off, washed with
water, dried, and recrystallized from 80% ethanol.
Yield 1.16 g (55%).
REFERENCES
1. Orazi, O.O., Corral, R.A., and Bertorello, H.E., J. Org.
Chem., 1963, vol. 28, p. 1101.
2. Sintezy iodistykh organicheskikh soedinenii (Syntheses
of Iodine-Containing Organic Compounds), Yagupol’-
skii, L.M., Novikov, A.N., and Merkushev, E.B., Eds.,
Tomsk, 1976, p. 89.
Iodination of deactivated aromatic compounds
XIIIa–XXIa with 1,3-diiodo-5,5-dimethylhydantoin
(I) in sulfuric acid (general procedure). Sulfuric acid
(90%, d = 1.825 g/cm3), 15 ml, was cooled to 0–3°C
and added to 5 mmol (1.9 g) of compound I, and the
mixture was stirred for 15–20 min at room temperature
until it became homogeneous. To introduce one iodine
atom into an aromatic substrate molecule, 5 mmol of
arene XIIIa–XXIa was added to the resulting dark
brown solution, and the mixture was vigorously stirred
for 20–120 min. To introduce two iodine atoms, the
3. Merkushev, E.B., Preparativnye sintezy iodaromatiche-
skikh soedinenii (Preparative Syntheses of Iodoaromatic
Compounds), Tomsk: Tomsk. Univ., 1985, p. 78.
4. Dictionary of Organic Compounds, Heilbron, J. and
Bunbury, H.M., Eds., London: Eyre and Spottswoode,
1953, vols. 2, 3.
5. Chaikovskii, V.K., Filimonov, V.D., Yagovkin, A.Yu., and
Ogorodnikov, V.D., Izv. Ross. Akad. Nauk, Ser. Khim.,
2001, no. 12, p. 2302.
6. Olah, G.A., Wang, Q., Sandford, G., and Prakash, G.K.S.,
J. Org. Chem., 1993, vol. 58, p. 3194.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 43 No. 9 2007
Chaikovskii
