The synthesis of ferrocenyl- and ferrocenoylpyrimidines

Article abstract of DOI:10.1134/S1070428014080132

New derivatives of pyrimidine were synthesized from ferrocenyl ketones by the reactions of [3+1+1+1]annulation and intermolecular cyclization. The electrochemical behavior of the obtained compounds was studied by the method of cyclic voltammetry. All the

Full text of DOI:10.1134/S1070428014080132

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2014, Vol. 50, No. 8, pp. 1150–1154. © Pleiades Publishing, Ltd., 2014.
Original Russian Text © K.Ya. Zherebker, А.N. Rodioneov, Е.S. Pilipenko, V.V. Kachala, О.M. Nikitin, Yu.А. Belousov, А.А. Simenel, 2014, published in
Zhurnal Organicheskoi Khimii, 2014, Vol. 50, No. 8, pp. 1167–1171.
The Synthesis of Ferrocenyl- and Ferrocenoylpyrimidines
K. Ya. Zherebker, А. N. Rodionova, Е. S. Pilipenkoa, V. V. Kachalab, О. M. Nikitina,c,
Yu. А. Belousova, and А. А. Simenela,d
a Nesmeyanov Institute of Organoelemental Compounds, Russian Academy of Sciences,
ul. Vavilova 28, Moscow, 119991 Russia
е -mail: alexsim@ineos.ac.ru
b Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia
c Lomonosov Moscow State University, Moscow, Russia
d Moscow State Mining University, Moscow, Russia
Received April 23, 2014
Abstract—New derivatives of pyrimidine were synthesized from ferrocenyl ketones by the reactions of
[3+1+1+1]annulation and intermolecular cyclization. The electrochemical behavior of the obtained compounds
was studied by the method of cyclic voltammetry. All the compounds may be characterized with the signal,
corresponding to the reversible one-electron transfer in ferrocene-ferrecinium and lowering of the redox
potential with respect to ferrocene.
DOI: 10.1134/S1070428014080132
Pyrimidine is one of the most wide spread natural
heterocycles and it is a key fragment of many bioactive
substances (like DNA, thiamine) and pharmaceuticals
(luminal). The fragments of 4,5-disubstitued
pyrimidine are often found in naturally occurring
bioactive agents (vorikonazol [1] and avitriptan [2]).
obtaining polymers with higher thermal stability, for
example, poly(methyl methacrylate) and polystyrene
[6]. As a result the development of effective methods
of synthesis of ferrocenyl-substituted pyrimidines
became an actual task.
The first known way of 4-ferrocenylpyrimidine
preparation is the reaction of ferrocenyllithium with
pyrimidine [7]. Now several methods are known of
substituted ferrocenylpyrimidine synthesis by the
reactions of cross-coupling [8] or condensation of β-
carbonyl compounds with urea or thiourea in the
presence of Lewis acids [9] and also the condensation of
the ferrocenyl ketones with the guanidine analogs [1,
10]. Among the defects of the described methods there
are low yields, application of catalysts, the necessity of
multistage synthesis in severe conditions [9].
The specific properties of ferrocene, including its
high stability, capability of reversible change of
oxidation state, nonbenzoid aromatic structure, low
toxicity for mammal organisms and potential use as
source of iron, make its derivatives ideal fragments for
development of new drugs.
In the last two decades the ferrocenyl derivatives of
purine and pyrimidine attracted high interest that might
be explained by their unique features, in particular,
redox properties, capability to penetrate cellar
membranes, and low toxicity [3]. Different compounds
were obtained, where fragments of ferrocene were in
various positions of purine and pyrimidine systems [4].
We developed a convenient one-stage method of
the preparation of 4,5-disubstitued ferrocenyl- and
ferrocenoylpyrimidine IIa–IIe by ZnCl2-cathalysed
three-component condensation of ferrocenylcarbonyl
compounds with triethyl orthoformate and ammonium
acetate.
The ferrocenylpyrimidine derivatives possess high
activity combined with low toxicity for various
microorganisms, for example the ameba [5]. Such
compounds may be used as initiators of radical
reactions, allowing decreasing the polymerization
temperature, increasing the reaction velocity, and
The initial acetylferrocene Ia and propionylfer-
rocene Ib were obtained by acylation of ferrocene with
the corresponding acid chlorides by Friedel-Krafts
1150

THE SYNTHESIS OF FERROCENYL- AND FERROCENOYLPYRIMIDINES
1151
Scheme 1.
R
O
R
N
NH4OAc, HC(OEt)3, ZnCl2, C6H5CH3
N
Fe
Fe
110oC
Ia-Ic
IIa-IIc
R = H (a), CH3 (b), COOCH3 (c).
reaction in dichloromethane using the aluminum
chloride as the catalyst [11].
1H/13C-heteronuclear correlations. In the 13С NMR
spectrum of the compound IId a singlet of carbon atom
of the С=О group is present at 197 ppm, and not a
quadruplet typical of 4-ferrocenyl-5-trifluoro-
acetylpyrimidine. Basing on this data we can state that
the product of the reaction is [4-(trifluoromethyl)
pyrimidin-5-yl](ferrocenyl)-methanone. If ethyl ferro-
cenoylpyruvate (Ie) is used in the same conditions the
reaction proceeds in another way, and as a result the
only isolated product of this process is ethyl 6-
ferrocenyl-pyrimidine-4-carboxylate (IIe) (Scheme 3).
1,3-Dicarbonyl derivatives Id and Ie may be
obtained by Claisen condensation of acetylferrocene Ia
and corresponding esters in the presence of sodium
ethylate [12, 13]. To increase the yield we used
potassium tert-butoxide in benzene [14] that made it
possible to simplify the isolation and purification of the
intermediate potassium salt. After adding equimolar
quantity of acetic acid to the salt suspension in
methylene chloride 4,4,4-trifluoro-1-ferrocenyl-butane-
1,3-dionee Id and ethyl ester of ferrocenyl-pyruvic acid
Ie were obtained in an overall yield 70–89%. The
1
In the H NMR spectra of the obtained compounds
there is a number of signals belonging to the protons of
the substituted and unsubstitued cyclopentadienyl rings
(3.90–4.44 ppm), pyrimidine protons (6.54–7.13 ppm),
and protons of the substituents. The assignment of the
signals in the 13C NMR spectra of the ferrocene
derivatives was made basing on the HSQC and HMBC
heteronuclear correlations.
1
presence in Н NMR spectra of compounds Id and Ie
of broad singlets at 14.95 and 15.26 ppm (ОН) and
singlets (1Н) at 6.54 (Id) and 6.09 ppm (Ie) proves that
they exist in the solution in the enol form. Methyl
ferrocenoylacetate (Ic) was obtained by the same
method from acetylferrocene and dimethyl carbonate.
4,5-Disubstituted pyrimidines may be obtained by
the [3+1+1+1]annulation and intermolecular
cyclization [15]. 4,5-Disubstituted ferrocenylpyrimi-
dines IIa-IIc were obtained in one stage by ZnCl2-
catalized three-component condensation of various
functionalized ferrocenylcarbonyl compounds with
triethyl orthoformate and ammonium acetate (Scheme 1).
The reaction of [3+1+1+1]annulation may be
carried out with the subsequent intramolecular
cyclization using various enamines [15] as initial
compounds. In that manner the functionalized enamine
III was obtained in a high yield, which was designed
to be used for ethyl 5-ferrocenoylpyrimidine-4-
carboxylate synthesis. Enamine III was obtained by
interaction of ethyl ferrocenoylpyruvate (Ie) and
methanol solution of ammonia in the presence of
ammonium acetate (Scheme 4).
If 4,4,4-trifluoro-1-ferrocenylbutane-1,3-dione is
used as the initial compound then the reaction product
would be [4-(trifluoromethyl)pyrimidin-5-yl](ferroce-
nyl)methanone IId (Scheme 2).
The pattern of signals in the 1H NMR spectrum
confirms that the reaction product is present in the
enamine form. The broad singlets are present in the
The structure of compound IId was established on
1
the bases of on the data of H and 13C NMR and
Scheme 2.
OH
O
O
CF3
CF3
NH4OAc, HC(OEt)3, ZnCl2, C6H5CH3
110oC
N
Fe
Fe
N
Id
IId
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 50 No. 8 2014

ZHEREBKER et al.
1152
Scheme 3.
COOEt
N
OH
O
OEt
NH4OAc, HC(OEt)3, ZnCl2, C6H5CH3
110oC
N
O
Fe
Fe
Ie
IIe
spectrum from the protons of the NH2 group at 5 and
9 ppm, and a singlet in the area of 9 ppm evidences the
formation of the hydrogen bond between NH and the
carbonyl group.
The position of the ester group in the pyrimidine ring
also does not change the value of the oxidation
potential. The oxidation potential of compound IIe
(685 mV) is more shifted in anoidic region comparing
to the oxidation potential of compound IIc that can be
caused by the influence of the acceptor carbonyl group
located between the ferrocene and the pyrimidine
fragment.
Enamine III was introduced in the reaction of
[3+1+1+1]annulation, however again the only isolated
reaction product was ethyl 6-ferrocenyl-pyrimidine-4-
carboxylate (IIe). At the attempt to synthesize
compound IIe from the ethyl ferrocenoylpyruvate and
the formamidine acetate only enamine III was
obtained. Nowadays the obtained compounds are
tested for the biological activity.
EXPERIMENTAL
The solvents were purified by standard methods
and distillated in argon atmosphere just before use.
The melting points of the substances were determined
using Boёtius microblock. The EI mass spectra were
recorded on the instrument Finnigan Polaris Q,
temperature of the ionization chamber 250°С. The
The electrochemical properties of pyrimidine
derivatives of ferrocene were studied by the cyclic
voltammetry. The study was carried out in acetonitrile
in the presence of 0.05 М Bu4NBF4 on a platinum
electrode using Ag/AgCl/KCl as a reference electrode.
1
energy of the ionizing electrons 70 eV. H and 13C
NMR spectra in deuterochloroform at 30°С were
registered on Bruker DRX-500 instrument with
working frequencies 500.13 and 125.76 МHz
correspondingly. Chemical shifts are measured
relatively to signals of residual protons of the solvent.
The full correlation of the signals of all recorded NMR
spectra was carried out by using NMR heteronuclear
correlations (HSQC and HMBC) applying the gradient
methods.
The voltammograms of all studied compounds
show the same reversible one electron redox-transfer,
most likely corresponding to the oxidation of the
ferrocene fragment. The oxidation potential of
compound IIc is 680 mV. This potential is more
anodic than the potential of unsubstitued ferrocene
(ЕOx 500 mV) because of the influence of the electron-
acceptor pyrimidine fragment. To compare the redox
potentials by the known method о-tolylferrocene was
obtained by reacting ferrocene with o-tolyldiazonium
chloride [16]. Its redox potential (540 mV) shows that
the pyrimidine ring possesses higher electon-acceptor
properties than the benzene ring. The similar oxidation
potentials of compounds IIc and IIb (675 mV) mean
that the nature of the substituent in the pyrimidine
fragment does not much affect the oxidation potential.
The Acros Organics reagents were used without
preliminary purification.
1,3-Dicarbonyl compounds. General method
[14]. To a suspension of 24.64 g (0.22 mol) of t-BuOK
in 300 mL of benzene was added 45.6 g (0.2 mol) of
acetylferrocene. To the mixture was added dropwise
Scheme 4.
O
OH
O
NH2
COOEt
COOEt
NH3_MeOH, CH3COONH4
50oC
Fe
Fe
III
Ie
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 50 No. 8 2014

THE SYNTHESIS OF FERROCENYL- AND FERROCENOYLPYRIMIDINES
1153
0.22 mol of the corresponding ester. The reaction
mixture was boiled while stirring for 2 h, then cooled
to room temperature. The potassium salt was filtered
off, washed with ether till colorless washings and
dispersed in CH2Cl2. The suspension was treated with
glacial acetic acid until pH 5 then the organic fraction
was washed with water and brine, dried with
anhydrous Na2SO4. The solvent was removed in a
vacuum on a rotary evaporator.
4- and 5-Ferrocenyl-substituted pyrimidine. Ge-
neral method. To a suspension of 6.8 mg (0.050 mmol)
of ZnCl2 and 220 mg (1.5 mmol) of triethyl
orthoformate in toluene was added 0.5 mmol of the
corresponding ketone and 77 mg (1.0 mmol) of
ammonium acetate. The reaction mixture was heated to
110°C while stirring, the course of the reaction was
monitored by TLC. The reaction mixture was treated
with 5 mL of concentrated solution of NaHCO3, the
products of the reaction were extracted with CHCl3,
the combined organic extracts were dried with Na2SO4.
The solvent was removed in a vacuum on a rotary
evaporator. The residue was chromatographed on a
column packed with silica gel (eluent ethyl acetate–
hexane, 3 : 1).
Methyl ferrocenoylacetate (Ic). Yield 80%. Red
1
crystals, mp 79–80°C. Н NMR spectrum, δ, ppm:
3.77 s (2H, CH2), 3.79 s (3H, CH3), 4.27 s (5H, Fc),
4.58 s (2H, Fc), 4.81 s (2H, Fc). 13C NMR spectrum, δ,
ppm: 46.7, 52.4, 69.7, 70.1, 73.0, 78.2, 168.0, 195.9.
Mass spectrum, m/z (Irel.,%): 286 [M]+ (100).
4-Ferrocenylpyrimidine (IIa). Yield 58%. Orange
oily substance. 1Н NMR spectrum, δ, ppm: 3.98 s (5H,
Fc), 4.44 s (2H, Fc), 4.90 s (2H, Fc), 7.22 d (1H, CH, J
5.1 Hz), 8.44 d (1H, CH, J 5.4 Hz), 8.95 s (1H, CH).
13C NMR spectrum, δ, ppm: 67.88, 70.00, 71.36,
79.67, 116.66, 155.90, 158.72, 167.94. Mass spectrum,
m/z (Irel., %): 264 [M]+ (100). Found, %: C 62.81; H
4.67; Fe 20.86. C14H12FeN2. Calculated, %: C 63.67; H
4.58; Fe 21.15. М 264.04.
4,4,4-Trifluoro-1-ferrocenylbutane-1,3-dione (Id).
Yield 83%. Dark violet crystals, mp 100–101°C. Н
1
NMR spectrum, δ, ppm: 4.24 s (5H, Fc), 4.69 s (2H,
Fc), 4.87 s (2H, Fc), 6.09 s (1H, CH), 15.26 b.s (1H,
OH). 13C NMR spectrum, δ, ppm: 69.53, 71.25, 74.17,
1
75.66, 93.41, 120.34 q (CF3, JC,F 279 Hz), 170.34 q
2
(C3, JC,F 35.5 Hz), 194.75. Mass spectrum, m/z (Irel.,
%): 324 [M]+ (100).
Ethyl ferrocenoylpyruvate (Ie). Yield 89%. Dark
violet crystals, mp 77°C (77°C [14]). 1Н NMR
spectrum, δ, ppm: 1.38 t (3H, CH3, J 7 Hz), 4.19 s (5H,
Fc), 4.34 q (2H, CH2, J 7 Hz), 4.62 s (2H, Fc), 4.85 s
(2H, Fc), 6.54 s (1H, CH), 14.95 b.s (1H, OH). 13C
NMR spectrum, δ, ppm: 14.0, 62.2, 69.3, 70.5, 73.4,
77.4, 100.0, 162.6, 163.6, 197.7. Mass spectrum, m/z
(Irel., %): 328 [M]+ (62).
5-Methyl-4-ferrocenylpyrimidine (IIb). Yield
50%. Orange crystals, mp 70°C. 1Н NMR spectrum, δ,
ppm: 2.47 s (1H, CH3), 4.08 s (5H, Fc), 4.50 t (2H, Fc,
J 2.1 Hz), 5.04 t (2H, Fc, J 2.1 Hz), 8.37 s (1H, CH),
8.91 s (1H, CH). 13C NMR spectrum, δ, ppm: 18.28,
69.86, 70.21, 71.02, 77.16, 81.25, 126.76,
19.76156.29, 158.02, 165.77. Mass spectrum, m/z (Irel.,
%): 278 [M]+ (100). Found, %: C 63.74; H 5.17; Fe.
C15H14FeN2. Calculated, %: C 64.78; H 5.07; Fe 20.08.
М 278.05.
Ethyl 2-amino-3-ferrocenoylprop-3-enoate III.
5 mmol of ethyl ferrocenoylpyruvate was dissolved in
7 N ammonium methanol solution and 385 mg (5 mmol)
of ammonium acetate was added. The reaction mixture
was heated to 50°C at stirring. The course of the
reaction was monitored by TLC. The solvent was
removed in a vacuum on a rotary evaporator. Pure
enamine III was obtained by chromatography of the
residue on silica gel (eluent CHCl3–МеОН, 9 : 1). Ora-
Methyl 5-ferrocenylpyrimidine-4-carboxylate
1
(IIc). Yield 85%. Orange crystals, mp 151–152°C. Н
NMR spectrum, δ, ppm: 3.93 s (3H, CH3), 4.06 s (5H,
Fc), 4.53 s (2H, Fc), 4.94 s (2H, Fc), 8.69 s (1H, CH),
9.07 s (1H, CH). 13C NMR spectrum, δ, ppm: 29.7,
52.67, 70.02, 70.11, 70.34, 71.53, 156.43, 158.71,
166.08, 167.40. Mass spectrum, m/z (Irel., %): 322 [M]+
(100). Found, %: C 58.86; H 4.51; Fe 17.02.
C16H14FeN2O2. Calculated, %: C 59.65; H 4.38; Fe
17.34. М 322.04.
1
nge crystals. Yield 80%. Н NMR spectrum, δ, ppm:
1.40 t (3H, CH3, J 6 Hz), 4.17 s (5H, Fc), 4.38 q (2H,
CH2, J 6 Hz), 4.47 s (2H, Fc), 4.82 s (2H, Fc), 5.72 b.s
(1H, NH), 6.19 s (1H, CH), 9.06 b.s (1H, NH). 13C
NMR spectrum, δ, ppm: 14.16, 62.50, 68.95, 69.95,
71.82, 81.69, 95.06, 144.77, 164.21, 195.83. Mass
spectrum, m/z (Irel, %): 327 [M]+ (100). Found, %: C
57.94; H 5.32; Fe 16.84. C16H17FeNO3. Calculated, %:
C 58.74; H 5.24; Fe 17.07. М 327.06.
[4-(Trifluoromethyl)pyrimidin-5-yl](ferrocenyl)
methanone (IId). Yield 70%. Orange oily substance.
1Н NMR spectrum, δ, ppm: 4.13 s (5H, Fc), 4.65 s
(2H, Fc), 5.08 s (2H, Fc), 7.57 s (1H, CH), 9.16 s (1H,
13
CH). C NMR spectrum, δ, ppm: 68.41, 70.30, 72.24,
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 50 No. 8 2014

ZHEREBKER et al.
1154
3
1
92.14, 121.80 q (С5, JC,F 7.5 Hz), 129.80 q (СF3, JC,F
6. Puzin, Yu.I., Yumagulova, R.Kh., and Kraikin, V.A.,
Eur. Polym. J., 2001, vol. 37, p. 1801; Krakin, V.A.,
Ionova, I.A., Pusin, Yu.I., Yumagulova, R.G.,
Monakov, Yu.B., Vysokomol. Soed. A, 2000, vol. 42,
p. 1569.
7. Chupakhin, O.N., Utepova, I.A., Kovalev, I.S., Rusi-
nov, V.L., and Starikova, Z.A., Eur. J. Org. Chem.,
2007, p. 857.
8. Braga, D., D’Addario, D., and Polito, M.,
Organometallics, 2004, vol. 23, p. 2810; Xu, C.,
Wang, Z.-Q., Fu, W.-J., Lou, X.-H., Li, Y.-F., Cen, F.-F.,
Ma, H.-J., Ji, B.-M., Organometallics, 2009, vol. 28,
p. 1909.
9. Yadav, J.S., Reedy, B.V.S., Srinivas, R., Venugopal, C.,
and Ramalingam, T., Synthesis, 2001, p. 1341; Ku-
mar, A.K., Kasturaiah, M., Reedy, S.C., and Reddy, C.D.,
Tetrahedron Lett., 2001, vol. 42, p. 7873; Peng, J.,
and Deng, Y.Q. Tetrahedron Lett., 2001, vol. 42,
p. 5917; Fu, N., Yuan, Y., Cao, Z., Wang, S., Wang, J.,
and Peppe, C., Tetrahedron, 2002, vol. 58, p. 4801;
Xia, M., and Wang, Y., Tetrahedron Lett., 2002,
vol. 43, p. 7703; Reddy, K.R., Reddy, C.V., Ma-
hesh, M., Raju, P.V.K., and Reddy, V.V.N.,
Tetrahedron Lett., 2003, vol. 44, p. 8173; Maiti, G.,
Kundu, P., and Guin, C., Tetrahedron Lett., 2003,
vol. 44, p. 2757; Varala, R., Alam, M.M., and Ada-
pa, S.R., Synlett., 2003, p. 67; Dondoni, A., Massi, A.,
Minghini, E., Sabbatini, S., and Bertolasi, V., J. Org.
Chem., 2003, vol. 68, p. 6172.
279 Hz), 146.13 q (C4, JC,F 32.5 Hz), 154.8, 159.00,
2
195.6. Mass spectrum, m/z (Irel.,%): 360 [M]+ (100).
Found, %: C 52.71; H 3.18; Fe 15.32. C16H11F3FeN2O.
Calculated, %: C 53.36; H 3.08; Fe 15.51. М 360.02.
Ethyl 6-ferrocenylpyrimidine-4-carboxylate
(IIe). Yield 78%. Red oily substance. 1Н NMR
spectrum, δ, ppm: 1.47–1.52 t (3H, CH3, J 15 Hz),
4.09 s (5H, Fc), 4.52–4.55 q (2H, CH2, J 9 Hz), 4.61 s
(2H, Fc), 5.08 s (2H, Fc), 7.96 s (1H, CH), 9.17 s (1H,
13
CH). C NMR spectrum δ, ppm: 14.26, 62.63, 68.33,
70.21, 72.05, 79.06, 116.26, 153.78, 159.07, 164.63,
170.95, 195.72. Mass spectrum, m/z (Irel.,%): 336 [M]+
(100). Found, %: C 59.15; H 4.96; Fe 16.18.
C17H16FeN2O2. Calculated, %: C 60.74; H 4.80; Fe
16.61. М 336.06.
The research was carried out with the financial
support of the Russian Academy of Sciences (the
program of Presidium of the Russian Academy of
Sciences “Fundamental sciences to the medicine,”
“Young scientists support” of the Department of
chemistry and material sciences “Medical chemistry”)
and of the Russian Foundation of Basic Research
(projects nos. 14-03-00980, 14-03-31469).
REFERENCES
10. Fu, N.-Y., Yuan, Y.-F., Pang, M.-L., Wang, J.-T.,
Peppe, C., J. Organometal.Chem., 2003, vol. 672, p. 52;
Csampai, A., Gyorfi, A.Z., Turos, Gy.I., and Sohar, P.,
J. Organometal.Chem., 2009, vol. 694, p, 3667.
11. Woodward, R.B., Rosenblum, M., and Whiting, M.C.,
J. Am. Chem. Soc., 1952, vol. 74, p. 3458.
12. Lacan, M., and Rapic, V., Croat. сhim. Acta, 1970,
1. Dickinson, R.P., Bell, A.S., Hitchcock, C.A.,
Narayanaswami, S., Ray, S.J., Richardson, K., and
Troke, P.F., Bioorg. Med. Chem. Lett., 1996, vol. 6, p. 2031.
2. Brodfuehrer, P.R., Chen, B.-C., Sattelberg, T.R.,
Smith, P.R., Reddy, J.P., Stark, D.R., Quinlan, S.L.,
and Reid, J.G., J. Org. Chem., 1997, vol. 62, p. 9192.
3. Zacepin, Т.S., Andreev, S.Yu., Gianik, Т., and
Oretskaya, Т.S., Russ. Chem. Rev., 2003, vol. 72, p. 537;
Kraatz, H.-B., J. Inorg. Organometal. Polymer. Mater.,
2005, vol. 15, p. 83; Staveren, D.R., and Metzler-Nolte, N.,
Chem. Rev., 2004, vol. 104, p. 5931.
vol. 42, p. 411.
13. Zhang, Q., Song, W.L., Sh. Hossain, A.M., Liu, Zh.D.,
Hu, G.Ju, Tian, Yu.P., Wu, J.Y., Jin, B.K., Zhou, H.P.,
Yanga, J.X., and Zhanga, Sh.Y., Dalton Trans., 2011,
vol. 40, p. 3510.
14. Rodioneov, A.N., Simenel, A.A., Korlyukov, A.A.,
Kachala, V.V., Peregudova, S.M., Zherebker, K.Ya.,
and Osipova, E.Yu., J. Organometal. Chem., 2011,
vol. 696, p. 2108.
4. Chen, S.-C., J. Organometal. Chem., 1980, vol. 202, p. 183;
Zhilina, Zh.V., Gumenyuk, V.V., Nekrasov, Yu.S., Ba-
bin, V.N., Snegur, L.V., Starikova, Z.А., and Yanovsky, А.I.,
Russ. Chem. Bull., 1998, vol. 47, p. 1781; Houlton, A.,
Isaac, C.J., Gibson, A.E., Horrocks, B.R., Clegg, W., and
Elsegood, M.R.J., J. Chem. Soc., Dalton Trans., 1999,
p. 3229.
15. Sasada, T., Kobayashi, F., Sakai, N., and Konakahara, T.,
Org. Lett., 2009, vol. 11, p. 2161.
16. Perevalova, E.G., Simukova, N.A., Nikitina, T.V.,
Reshetov, P.D., and Nesmeyanov, A.N., Bull. Acad. Sci.
USSR, Divis. Chem. Sci., 1961, vol. 10, p. 67.
5. Parveen, H., Hayat, F., Salahuddin, A., and Azam, A.,
Eur. J. Med. Chem., 2010, vol. 45, p. 3497.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 50 No. 8 2014