Russian Journal of Applied Chemistry, 2012, Vol. 85, No. 9, pp. 1395−1398.
Pleiades Publishing, Ltd., 2012.
Original Russian Text © P.Yu. Andreev, 2012, published in Zhurnal Prikladnoi Khimii, 2012, Vol. 85, No. 9, pp. 1482−1486.
AND INDUSTRIAL ORGANIC CHEMISTRY
Reaction of Ozone with Five-Membered
Hetarenes in a Liquid Phase
P. Yu. Andreev
Institute of Chemical Technologies, Dal’ East-Ukrainian National University,
Rubezhnoe, Lugansk oblast, Ukraine
Received December 14, 2011
Abstract—Oxidation of pyrrole, furan, and thiophene by ozone in a solution of glacial acetic acid was studied.
Peroxide compounds, which are, presumably, dimers of linear structure, were found as primary products. The
kinetics of ozonolytic reactions with ﬁ ve-membered hetarenes was examined, and rate constants and experimental
stoichiometric coefﬁ cients for ozone were determined.
Pyrrole I, furan II, and thiophene III exhibit a
considerable reactivity toward ordinary electrophilic
reagents. In this regard, these compounds resemble
the most reactive derivatives of benzene, anilines and
phenols . The increased sensitivity to electrophilic
substitution is caused by the asymmetric charge
distribution in these heterorings due to the fact that six
π-electrons in their rings are shared by ﬁ ve atoms .
Pyrrole, furan, and derivatives of these are easily
oxidized and turn dark when allowed to stay in air .
However, studies concerned with the reaction of these
heterorings with such an electrophilic oxidation agent
as ozone are scarce.
The goal of our study was to examine reactions of
compounds I–III with ozone in a solution of glacial
It was shown in  that, in ozonation of compounds
I and II in chloroform, 2 moles of ozone are absorbed
per mole of a substrate to give glyoxal and ormic acid,
with a strong tarring of the reaction solution.
In oxidation of compounds I–III by ozone in an
acetic acid solution at 290°C, peroxide compounds
were found as primary products. Presumably, these
compounds have the form of a hydroperoxy peroxide:
O CH C
where X = NH, O, S.
The hydroperoxy peroxide structure is conﬁ rmed by
the following observations. The experimentally found
stoichiometric coefﬁ cient of ozone, nexp, is close to
2 mol per mole of a hetarene (Table 1). The peroxides
under study react with potassium iodide in two stages;
during the ﬁ rst, fast, stage (1 h), molecular iodine is
released in an amount equivalent to a single terminal
hydroperoxide group; with an additional group of the
same type released during the second, slow (12 h), stage
(Table 1). After 12 h, the release of molecular iodine
stops. According to published data , hydroperoxide
groups more readily enter into the reaction with
potassium iodide, with peroxide groups of dialkyl
peroxide nature reduced much more difﬁ cultly.
Alkaline hydrolysis of peroxide compounds formed
in ozonolysis of pyrrole results in release of ammonia in
a nearly quantitative yield per the reacted pyrrole.
To reﬁ ne their structure, we recorded R spectra of
the hydroperoxy peroxides obtained. Based on the IR