Oxidation of procainamide by diperiodatocuprate(III) complex in aqueous
alkaline medium: a comparative kinetic study
a
b
b
Manjunath D. Meti , Sharanappa T. Nandibewoor , and Shivamurti A. Chimatadar
a
b
Department of Chemistry, Indian Institute of Technology, Bombay 400076, India; P.G. Department of Studies in Chemistry, Karnatak
University, Dharwad 580003, India
ABSTRACT
ARTICLE HISTORY
A comparative study of uncatalysed and ruthenium(III) catalyzed oxidation of procainamide(PAH)
was carried out spectrophotometrically using diperiodatocuprate(III) in aqueous alkali.
Stoichiometry observed was 1:2 (PAH: DPC). The reaction was of first order in both catalyzed and
uncatalyzed cases, with respect to [DPC] & [Ru(III)], less than unit order in [PAH] and [alkali].
Negative fraction in [periodate]. Other kinetic parameters viz., ionic strength, dielectric constant,
temperature effect and intervention of free radical were also studied. The main oxidation products
were characterized by different techniques. The activation parameters with respect to slow step of
the mechanism, also the thermodynamic quantities were determined.
Received 9 April 2018
Accepted 24 August 2019
KEYWORDS
Diperiodatocuprate(III); oxi-
dation; procainamide;
ruthenium(III) catalyst;
thermodynamic parameters
Introduction
effect. The rate became tenfold faster than the uncatalysed
reaction in this concentration range of the catalyst.
[1,2]
In the latest past , the study of maximum oxidation state
of transition metals has attracted several scientists. Some
relatively stable copper(III) complexes have been prepared
namely, the periodate, guanidine and tellurate complexes are
good oxidants in a medium with an appropriate pH value.
Copper complexes have occupied a vital place in oxidation
chemistry due to their abundance and wide applications in
biological chemistry. Diperiodatocuprate (III) (DPC) is a
versatile one-electron oxidant and its oxidation study is
revealing in view of its partial solubility and stability in
aqueous medium. Its usefulness as an analytical reagent is
Procainamide [PAH] used for the treatment of cardiac
arrhythmias, especially to treat certain types of irregular heart-
[8]
beats (ventricular tachycardia). Procainamide hydrochloride
(salt form of procainmide) is a group 1A cardiac antiarrhyth-
mic drug, is p-amino-N-f2-(diethylamino)ethylg-benzamide
monohydrochloride. Procainamide’s major active metabolite
is N-acetylprocainmide (NAPA), which is approximately
[
3]
[9]
equipotent with the parent drug as an antiarrhythmic agent.
The structure of procainamide is shown below
[
4]
present well familiar.
The oxidation reaction usually
involves the copper(II)–copper(I) and such aspects are dealt
[
5]
3þ
5]
2þ
in different reviews. The Cu /Cu reduction potential is
–
[
1.18 V in alkaline solution. When copper(III) periodate
complex acts as an oxidant, many equilibrium steps between
different copper(III) species are involved and it would be
interesting to know about the active oxidants. The kinetics
of self-decomposition of these complexes was also studied
Procainmaide is also used as a chromatography resin,
[
10]
because it binds protein.
It is structurally similar to pro-
caine, but in place of an ester group, procainamide contains
an amide group. Because of this substitution procainamide
exhibits a longer half-life time than procaine.
[
2]
in detail.
Ruthenium(III) (Ru(III)) acts as an efficient catalyst in the
several oxidations of many organic and inorganic substrates &
Literature survey revealed that some work on oxidation of
[11]
it has gain attention in recent years owing to catalytic applica- PAH by various oxidants have been carried out , there is a
[
6]
tions in various technologies. Ruthenium(III) catalysis in lack of literature on the oxidation of this PAH by DPC and its
redox reactions contains different steps of complexity, due to catalysis by ruthenium(III). In view of the pharmaceutical
the formation of different reaction intermediate complexes importance of PAH and oxidation of procainamide by DPC,
[
7]
and the different oxidation states of ruthenium. An ideal there was a need for understanding the mechanistic profile.
catalyst is the one which shows a good catalytic effect at a neg- Hence, the present investigation is aimed to find out the reactiv-
ꢀ
6
ꢀ3
ligible concentration range; hence, a micro (10 mol dm
)
ity of PAH towards DPC in both uncatalyzed and ruthenium(III)
quantity of the ruthenium(III) is used to study the catalytic catalyzed reactions, to identify the reactive species of DPC,
CONTACT Dr. Manjunath D. Meti
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Indian Institute of Technology, IIT Bombay, Powai, Mumbai-400076, Maharashtra, INDIA.