Kinetic studies of the copper-catalyzed cross-coupling of 1-phenyltetrazole-5-thiol and iodobenzene

Article abstract of DOI:10.1134/S1070363213090132

Kinetics of the copper-catalyzed cross-coupling of 1-phenyltetrazole-5- thiol and iodobenzene under thermal and dielectric heating has been studied; the kinetic parameters of the reaction have been calculated. Microwave irradiation has not influenced sign

Full text of DOI:10.1134/S1070363213090132

ISSN 1070-3632, Russian Journal of General Chemistry, 2013, Vol. 83, No. 9, pp. 1707–1709. © Pleiades Publishing, Ltd., 2013.
Original Russian Text © U.N. Dmitrieva, T.V. Artamonova, Yu.E. Zevatskii, N.P. Novoselov, L.V. Myznikov, 2013, published in Zhurnal Obshchei Khimii,
2013, Vol. 83, No. 9, pp. 1486–1489.
Kinetic Studies of the Copper-Catalyzed Cross-Coupling
of 1-Phenyltetrazole-5-thiol and Iodobenzene
U. N. Dmitrieva, T. V. Artamonova, Yu. E. Zevatskii, N. P. Novoselov, and L. V. Myznikov
St. Petersburg State University of Technology and Design, ul. Bol’shaya Morskaya 18, St. Petersburg, 191186 Russia
e-mail: batarlykova.ulya@mail.ru
Received May 16, 2013
Abstract—Kinetics of the copper-catalyzed cross-coupling of 1-phenyltetrazole-5-thiol and iodobenzene under
thermal and dielectric heating has been studied; the kinetic parameters of the reaction have been calculated.
Microwave irradiation has not influenced significantly the reaction molecular mechanism; the process
acceleration can be due to macrokinetic effects.
DOI: 10.1134/S1070363213090132
Cross-coupling with formation of carbon–
heteroatom bond is one of the most efficient methods
for heterocyclic compounds modification [1]. Such
reactions are convenient for preparation of biologically
active compounds. Kinetics and mechanism of the
copper-catalyzed С–N cross-coupling have been studied
in a number of works [2–4], however, similar studies
of C–S cross-coupling have not been reported.
We suggested that the reaction proceeded via
formation of the soluble copper complex with iodo-
benzene that further interacted with 1-phenyl-tetrazole-
5-thiol in dimethylformamide (DMF) solution upon
heating.
Kinetic measurements were performed at 65, 80,
and 95°С both with convectional and microwave
heating. The initial substances and products concentra-
tions were determined by high-performance liquid
chromatography.
Recently, we have discovered that 1-substituted tetra-
zole-5-thiols can participate in the copper-catalyzed
cross-coupling with aryl iodides, and have noticed that
microwave irradiation influences the reaction duration
[5]. Extending the study of this reaction, in this work
we investigated its kinetics under convectional and
dielectric heating.
Kinetic curves of the product, 1-phenyl-5-sulfanyl-
tetrazole III, formation at different temperatures are
shown in Figs. 1 and 2 (under convectional heating and
microwave activation, respectively).
The cross-coupling of 1-phenyltetrazole-5-thiol (I)
with iodobenzene (II) was chosen as a model reaction.
As seen from the curves, the microwave activation
significantly affected the product formation rate.
In the frame of the activated complex theory, the
rate constant, the reaction activation energy (Еа),
enthalpy (ΔН≠), and entropy (ΔS≠) were calculated
from the experimental data, in the cases of both con-
vectional and microwave heating. The calculations
were performed using differential method and method
of stationary concentrations.
I
SH
N
+
N
N
N
I
II
K2CO3,
CuI,
(CH2NH2)2
Differential method is based on the differential
form of the equation linking the product formation rate
with the rate constant and reaction orders with respect
to the starting compounds.
S
N
N
N
N
ln w = ln k + pIln cI + pIIln cII.
(1)
III
1707

1708
DMITRIEVA et al.
Time, min
Time, min
Fig. 1. Kinetic curves of 1-phenyl-5-sulfanyltetrazole accu-
mulation under convection heating at (1) 65, (2) 80, and
(3) 95°С.
Fig. 2. Kinetic curves of 1-phenyl-5-sulfanyltetrazole accu-
mulation under microwave heating at 65 (1) 65, (2) 80, and
(3) 95°С.
In Eq. (1), w is the product formation rate, k is the
rate constant. The reaction rate was calculated using
the second order polynomial interpolation (2):
approach was possibility of independent determination
of the reaction orders and the rate constant. Kinetic
experiment with the excess of one of the reagents was
not required. The results are collected in Table 1.
c = aτ2 + bτ + d,
(2)
where τ being time; а, b, d being the coefficients
deduced from three products concentrations сi–1, сi, сi+1
at times τi–1, τi, τi+1, respectively. The reaction rate at
time τi was determined according to Eq. (3).
Upon microwave irradiation, the calculated rate
constant at 80°С was higher than that at 95°С, the
indirect measurements accuracy being the worst of all
the measurements; thus, the data obtained at 80°С
were neglected in subsequent calculations of the
activation energy.
wi = 2aτi + b.
(3)
The rate constant and the reaction orders were
obtained via solution of the equations set emerged from
the partial least square method. The advantage of that
The activation energy was calculated from the rate
constants determined at different temperatures; the
Table 1. Reaction order and rate constants of 1-phenyltetrazole-5-thiol arylation with iodobenzene under microwave and
convectional heating
k, s–1
Partial reaction order with respect to the reagents
microwave heating convectional heating
Temperature,
°С
microwave heating
convectional heating
I
II
I
II
65
80
95
(5.1±2.7)×10–5
(7.7±4.2)×10–3
(2.3±0.5)×10–3
(1.0±0.4)×10–5
(6.0±1.8)×10–5
(1.7±1.4)×10–3
1.0
1.2
1.0
1.0
1.2
1.2
1.0
1.9
1.9
0.8
1.2
1.6
Table 2. Kinetic parameters of 1-phenyltetrazole-5-thiol arylation with iodobenzene under microwave and convectional
heating
Еа, kJ mol–1
ΔS≠, J mol–1 K–1
Method
microwave activation convectional heating microwave activation convectional heating
Differential
Stationary concentrations
131
126
175
135
10.3
9.5
14.2
10.0
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 83 No. 9 2013

KINETIC STUDIES OF THE COPPER-CATALYZED CROSS-COUPLING
1709
calculations were performed according to the
EXPERIMENTAL
1-Phenyl-5-sulfanyltetrazole
according to [5]. Starting 1-phenyltetrazole-5-thiol was
recrystallized from propanol-2; iodobenzene was
distilled under reduced pressure.
Arrhenius equation in its differential form, taking
advantage of the partial least square method. In the
frame of the activated complex theory, Еа being equal
to the activated complex enthalpy Н≠, the correspond-
was
prepared
ing enthalpy ΔS≠ was calculated.
≠
Kinetic studies were performed with Shimadzu
Prominence LC-20 HPLC instrument [eluent: MeCN–
H2O (3:2), column temperature of 30°С, column:
SUPEL-CO Supelcosil LC-18-DB 150×4.6 mm, flow
rate of 1 ml min–1].
k(T) = AeΔH /RT
(4)
(5)
,
≠
kT
A = χ –— ·eΔS /R
.
h
In Eq. (5), χ is the transmission coefficient, χ ≈ 1; h
is Planck’s constant. The activation entropy was cal-
culated as in Eq. (6).
General procedure [5]. A mixture of 0.5 g
(2.79 mmol) of 1-phenyltetrazole-5-thiol, 0.56 g
(2.79 mmol) of iodobenzene, 0.96 g (7 mmol) of
K2СО3, 0.106 g (0.56 mmol) of CuI, and 0.033 g
(0.56 mmol) of ethylenediamine in 10 ml of DMF was
heated at a chosen temperature upon stirring.
h
≠
.
(6)
Rln A
ΔS =
kT
The values of Еa, and ΔS≠ were calculated accord-
ing to the stationary concentrations method as well.
The results were in good agreement with those from
the differential method (Table 2).
REFERENCES
1. Niu, L.-F., Cai, Y., Liang, C., Hui, X.-P., and Xu, P.-F.,
Tetrahedron, 2011, vol. 67, p. 2878.
From Table 2, the activation energy and entropy
from different methods were similar for the cases of
convectional and microwave heating. The close values
of Ea under different heating conditions showed the
absence of any specific microwave effect. The
acceleration of the copper-catalyzed 1-phenyltetrazole-
5-thiol arylation with iodobenzene under conditions of
microwave irradiation could be due to intensification
of the macrokinetic processes.
2. Larsson, P.-F., Bolm, C., and Norrby, P.-O., Chem. Eur. J.,
2010, vol. 16, p. 13613.
3. Larsson, P.-F., Bolm, C., and Norrby, P.-O., Beilstein J.
Org. Chem., 2012, vol. 8, p. 1909.
4. Sperotto, E., van Klink, G.P.M., van Koten, G., and de
Vries, J.G., Dalton Trans., 2010, vol. 39, p. 10338.
5. Dmitrieva, U.N., Ramsh, S.M., Zevatskii, Yu.E.,
Artamonova, T.V., and Myznikov, L.V., Chem.
Heterocyclic Comp., 2012, vol. 48, no. 2, pp. 355–357.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 83 No. 9 2013