ISSN 1070-4280, Russian Journal of Organic Chemistry, 2016, Vol. 52, No. 3, pp. 433–436. © Pleiades Publishing, Ltd., 2016.
Iodination of Industrially Important Aromatic Compounds
with Aqueous Potassium Triiodide*
V. Sharmaa, P. Srivastavab, D.D. Agarwalb, and K. Diwedib
a Department of Chemistry, Baba Farid College, Bathinda 151001, Punjab, India
phone: +91-9888471209; e-mail: bhardwajvivek68@gmail.com
b Department of Industrial Chemistry, Jiwaji University, Gwalior 474011, Madhya Pradesh, India
Received December 4, 2014
Abstract—A new reagent system consisting of aqueous KI3 in AcOH and NaIO4 as oxidant has been found to
be effective in iodinating a variety of commercially important aromatic substrates under ambient conditions.
The presence of Na2SO3 enhances the yield and the product purity. The procedure ensures high yields (72–
98%) at room temperature in a short reaction time. A remarkable feature of this system is that even acid-
sensitive functionalities like anilines can be iodinated quantitatively.
DOI: 10.1134/S1070428016030234
The chemistry of organic iodides and iodination
methods are of keen interest as they find various
industrial applications [1–2], in particular in synthesis
of various pharmaceutical and bioactive materials [3].
However, the low electrophilicity of molecular iodine
compared to molecular bromine and chlorine makes
direct iodination difficult [4]. Therefore, iodination of
aromatic substrates requires the presence of a strong
oxidant [5–8]. Some reported systems have enormous
potential in terms of the green chemistry principles,
e.g., I2/H2O2, I2/HIO3, NH4I/H2O2, HIO3/KI [9–12].
However, most known procedures are not free from
such drawbacks as poor yield, long reaction time,
harsh reaction conditions, and the use of hazardous or
toxic reagents. Thus, there is a need of an environ-
mentally friendly, mild, clean, efficient, easy to work-
up, and cost-effective system. In the present investiga-
tion, iodinated aromatic compounds of industrial inter-
est have been synthesized in good yields (72–98%)
using aqueous potassium triiodide (KI3) as an iodinat-
ing agent at room temperature.
water, and the solid product was filtered off, washed
with water, and dried. The melting points of the
products were in agreement with those reported in the
literature. The product structure was also confirmed by
1H NMR, FT-IR, and mass spectra.** The superiority
of the proposed system was demonstrated by com-
paring with that reported in [13]. The iodination
system was first tried on 4-nitroaniline (1a) as a model
substrate, which afforded 2-iodo-4-nitroaniline. The
iodination of 1a using NaIO4 alone (in the absence of
KI3) failed to give any product. The iodination of 1a in
AcOH with aqueous KI3 using NaIO4 as oxidant and
H2SO4 as acid source at room temperature gave 93%
of 2-iodo-4-nitroaniline (see table). When Na2SO3 was
added to the reaction mixture, the yield of 2-iodo-4-
nitroaniline increased to 98% (2 h). When the concen-
tration of KI3 was varied from 0.01 to 0.005 and then
to 0.0025 mol (0.01 mol of 1a and 0.01 mol of NaIO4),
the yield was found to decrease from 98 to 26 and 1.9,
respectively. Likewise, variation of the NaIO4 concen-
tration from 0.01 to 0.005 and then to 0.0025 mol
(0.01 mol of 1a and 0.01 mol of KI3) led to decrease of
the yield from 98 to 21 and 1.0%, respectively. Hence,
equimolar ratio of the substrate, KI3, and NaIO4 may
be proposed as the best stoichiometry. 2-Iodo-4-nitro-
aniline was found useful in the treatment of ubiquitin
conjugation-associated disorders, particularly hyper-
proliferative disorder [14]. Johnson et al. [15] have
reported the formation of 2-iodo-4-nitroaniline at 0°C
Aqueous KI/I2 is a mild, efficient, cheap, and
environment-friendly iodinating agent which is readily
prepared by adding molecular iodine to an aqueous
solution of KI at room temperature (25°C). The iodin-
ating agent was rapidly added to a stirred solution of
10 mmol of an aromatic substrate dissolved in 10 mL
of acetic acid. Most of the substrates were iodinated at
room temperature in a short time. When the reaction
was complete, the reaction mixture was quenched with
** The spectral data for all synthesized compounds and other
relevant information are available from the authors.
* The text was submitted by the authors in English.
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