5-(Naphth-1-yl)- and 5-[(1,1'-biphenyl)-4-yl]isoxazole-3-carbaldehyde oximes: Synthesis, complexes with palladium, and application in catalysis

Article abstract of DOI:10.1134/S1070363214090242

1-(Naphth-1-yl)- and 1-[(1,1'-biphenyl)-4-yl-3,4,4-trichloro-3-buten-1-ones were synthesized by acylation of naphthalene and biphenyl with 3,4,4-trichloro-3-butenoyl chloride. Further reaction with hydroxylamine led to 5-(naphth-1-yl)- and 5-[(1,1'-biphen

Full text of DOI:10.1134/S1070363214090242

ISSN 1070-3632, Russian Journal of General Chemistry, 2014, Vol. 84, No. 9, pp. 1782–1792. © Pleiades Publishing, Ltd., 2014.
Original Russian Text © V.I. Potkin, N.A. Bumagin, V.M. Zelenkovskii, S.K. Petkevich, M.V. Livantsov, N.E. Golantsov, 2014, published in Zhurnal
Obshchei Khimii, 2014, Vol. 84, No. 9, pp. 1546–1556.
5-(Naphth-1-yl)-
and 5-[(1,1'-Biphenyl)-4-yl]isoxazole-3-carbaldehyde Oximes:
Synthesis, Complexes with Palladium,
and Application in Catalysis
V. I. Potkina, N. A. Bumaginb, V. M. Zelenkovskiia,
S. K. Petkevicha, M. V. Livantsovb, and N. E. Golantsovb
a Institute of Physical Organic Chemistry, National Academy of Sciences of Belarus,
ul. Surganova 13, Minsk, 220072 Belarus
е-mail: potkin@ifoch.bas-net.by
b Lomonosov Moscow State University, Chemical Department, Moscow, 119991 Russia
e-mail: bna51@mail.ru
Received April 21, 2014
Abstract—1-(Naphth-1-yl)- and 1-[(1,1'-biphenyl)-4-yl-3,4,4-trichloro-3-buten-1-ones were synthesized by
acylation of naphthalene and biphenyl with 3,4,4-trichloro-3-butenoyl chloride. Further reaction with
hydroxylamine led to 5-(naphth-1-yl)- and 5-[(1,1'-biphenyl)-4-yl]isoxazole-3-carbaldehyde oximes. The latter
form complexes with palladium, which possess high catalytic activity in the Suzuki reaction in aqueous and
aqueous-alcoholic media.
Keywords: isoxazoles, oximes, complexes with palladium, catalyst, cross-coupling, quantum-chemical
calculations
DOI: 10.1134/S1070363214090242
Palladium complexes are effective catalysts for the
formation of the carbon–carbon and carbon–hetero-
atom bond in cross-coupling reactions and are widely
used in organic synthesis for preparation of
polyfunctional biaryls, arylated olefins, acetylenes, and
their heterocyclic analogs [1–3]. Compounds of this
type are structural fragments of modern drugs, liquid
crystal compositions used for preparation of lumino-
phores and dyes.
form complexes with palladium(II), which exhibited a
high catalytic activity in cross-coupling reactions in
aqueous media (“green chemistry”) [4–6]. Encapsula-
tion of the isoxazole and isothiazole palladium
complexes into the silica matrix allowed obtaining
multi-usable heterogeneous catalysts which can be
reused without loss of activity after 10 recycles [7].
In continuation of the studies on elaboration of
efficient catalytic systems for cross-coupling reactions
[8–17], the present report concerns the design and
synthesis of isoxazole ligands: oximes of 5-(naphth-1-
yl)- and 5-[(1,1'-biphenyl)-4-yl]isoxazole-3-carbalde-
hydes I, II having along with the electron-acceptor
azole ring the electron-donor nitrogen atom of the
oxime group. According to the data of quantum-
chemical calculations of ligands I, II, the excess
electron density is localized on the oxime group whose
total charge is –0.227 in (I) and –0.168 in (II), whereas
heterocyclic fragments bear partial positive charge of
+0.229 and +0.408, respectively (the total charge of
An important parameter determining the efficiency
of cross-coupling reactions is the nature of the ligand
in the palladium complex used as a catalyst. Taking
into account modern requirements, the trend to use
alternative types of ligands instead of toxic, readily
oxidized by air oxygen, and expensive conventional
triorganylphosphines can be easily understood. As
such ligands compounds of different types were
suggested, but as to the ligands of the isoxazole type,
they are poorly studied. Recently, we showed that
derivatives of isoxazole and isothiazole are capable to
1782

5-(NAPHTH-1-YL)- AND 5-[(1,1'-BIPHENYL)-4-YL]ISOXAZOLE-3-CARBALDEHYDE OXIMES
1783
the naphthyl substituent is –0.002 and of the biphenyl
substituent, –0.240). Calculations were performed at
the HF/MIDI(3d) level of theory with full geometry
optimization [18]. This level of theory allows to ade-
quately describe the structure of palladium complexes
with the ligands under consideration (vide infra).
ketone IV in methanol was non-selective and led to the
formation of a mixture of products containing only a
minor amount of the target 5-bi-phenylisoxazole II.
The reaction in ethanol was found to be the reaction of
choice leading to 5-biphenyl-isoxazolecarbaldehyde
oxime II in 40% yield.
It was assumed that the presence of two opposite in
nature coordination centers (the oxime group and the
isoxazole ring) in the ligand molecule would allow
palladium stabilization in different oxidation states,
avoiding the premature formation of Pd black and
deactivation of the catalyst in the course of the
catalytic cycle. Besides, we believe that the presence
of naphthyl and biphenyl substituents in the ligand
molecules should promote more strong noncovalent
bonding of the 1,2-azole palladium complexes with the
surface of the support upon heterogenization due to π-
π stacking.
Ketones III, IV and oximes of 5-arylisoxazole-3-
carbaldehydes I, II were identified by elemental
1
analysis, IR, Н, 13С NMR spectroscopy. In the IR
spectra of ketones III, IV intense absorption bands of
the carbonyl group are present at 1680 cm–1. In the IR
spectra of the isoxazole derivatives I, II the О–Н
vibrations of the oxime fragments appear as wide
absorption bands in the range 3220–3278 cm–1. The 1Н
NMR spectra of ketones III, IV contain singlets of the
methylene groups at δ 4.37 and 4.33 ppm, respectively,
and multiplets of aromatic protons. The formation of
the isoxazole heterocycle is proved by the presence of
singlets of the =CH protons at δ 7.07–7.11 ppm in the
1Н NMR spectra of compounds I, II.
The synthesized oximes of 5-naphthyl(biphenyl)iso-
xazole-3-carbaldehyde I, II were used for preparation
of complexes with palladium dichloride by the reaction
with sodium tetrachloropalladate. Complexes VI, VII
PdCl2-L [L = 5-(naphth-1-yl)isoxazole-3-carbaldehyde
oxime (I) or 5-(1,1'-biphenyl-4-yl)isoxazole-3-carbal-
dehyde oxime (II)] are formed by the reaction of
equimolar amounts of sodium tetrachloropalladate and
ligands I, II in methanol at 20°С. Specific dark-brown
color of the reaction mixture caused by Na2PdCl4
instantly turns yellow-red upon mixing of the reagents,
and a brick-red precipitate is separated. According to
thin-layer chromatography, the starting isoxazole
oximes I, II competely disappear after 5–10 min.
As starting compounds for the synthesis of naph-
thyl- and biphenyl-substituted isoxazoles 1-(naphth-1-
yl)-3,4,4-trichloro-3-buten-1-one (III) and 1-[(1,1'-bi-
phenyl)-4-yl]-3,4,4-trichloro-3-buten-1-one (IV) have
been chosen, which were synthesized by acylation of
naphthalene and biphenyl with 3,4,4-trichloro-3-
butenoyl chloride (V). The latter was prepared by
successive transformations of the easily accessible
dimer of trichloroethylene [19]. The acylation was
carried out under the conditions of Friedel–Crafts reac-
tion in the presence of unhydrous aluminum chloride
as a catalyst. We have also adopted and optimized the
protocol [20] used by us earlier for the synthesis of phenyl
(4-methylphenyl,
4,5-dimethylphenyl)trichloroallyl
ketones differing in that the reaction of acylation of
naphthalene and biphenyl with 3,4,4-trichloro-3-enoyl
chloride was performed in methylene chloride rather
than in the corresponding arene because both naph-
thalene and biphenyl are solids. The yields of ketones
III, IV reached 80–85%.
The synthesized palladium complexes VI, VII were
identified by elemental analysis and IR spectroscopy,
which showed the presence of characteristic vibration
bands of the C=N and C=C bonds of the isoxazole
heterocycles and the corresponding exocyclic fragments.
The synthesized naphthyl(biphenyl)trichloroallyl
ketones III, IV underwent heterocyclization by the
reaction with excess hydroxylamine to afford the
corresponding 5-(naphth-1-yl)- and 5-[(1,1'-biphenyl)-
4-yl]isoxazole-3-carbaldehyde oximes I, II. In the case
of naphthyltrichloroallyl ketone III the reaction was
carried out similar to the earlier elaborated procedure
for heterocyclization of phenyl(4-methylphenyl, 4,5-
dimethylphenyl)trichloroallyl ketones (reflux in me-
thanol) [21, 22], the yield of 5-naphthylisoxazole-3-
carbaldehyde oxime (I) was 85%. Unlike naphthyl-
trichloroallyl ketone III, heterocyclization of biphenyl
Complexes VI, VII are insoluble in organic sol-
vents and water, which does not allow to register their
NMR spectra and to grow single crystals for X-ray
analysis. Therefore their structure was analyzed by
using quantum chemical calculations of the molecular
geometry and IR spectra and comparison of the
calculated frequencies with the experiment (Scheme 1).
Earlier, by the example of similar palladium(II)
complexes with isoxazole ligands we have shown that
satisfactory results can be obtained by the use of DFT
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1784
POTKIN et al.
Scheme 1.
O
Cl
Cl
Cl
Cl
ArH
O
Cl
Ar
AlCl ,
CH2Cl2
3
Cl
Δ, 4 h
Cl
V
III, IV
NH2OH,
EtOH
(MeOH)
Δ,
12 h
NOH
NOH
Na2PdCl4
MeOH
N
Ar
N
Pd Cl
Cl
Ar
O
O
VI, VII
I, II
(II, IV,VII).
Ar =
(I, III, VI),
method at the B3LYP1/MIDI(3d) level of theory [4].
However, in the case of complexes VI, VII, the
procedure of geometry optimization cannot be
completed and no minima can be found on the
potential energy surface. Therefore, we have used the
HF/MIDI(3d) method with full geometry optimization
[18], as in the case of ligands I, II.
The calculations showed that isoxazole ligands in
complexes VI, VII coordinate to palladium atom in a
bidentate cyclic type via the nitrogen atoms of the
heterocycle and the exocyclic oxime group with the
formation of five-membered metallacycle. In complex
VI, the naphthyl fragment is turned by 48.1° with
respect to the rest of the molecule, which is practically
planar. In complex VII, the remote phenyl fragment is
also turned by 48° with respect to the plane of the
molecule, whereas in the fragment isoxazole–phenyl
the deviation of the benzene ring from the plane of the
molecule does not exceed 0.2°. Thus, in both cases, the
effective conjugation of the aromatic fragments with
the isoxazole heterocycle is violated.
VI
The deviation of atoms from the plane in the
fragment PdN2Cl2 does not exceed 1.7° for complex
VI and 0.14° for complex VII. Structural charac-
teristics of the heterocyclic and oxime fragments of the
ligands for the two complexes are very similar and
only slightly different from the corresponding param-
eters of the complexes of 5-(2,5-dimethylphenyl)iso-
xazole-3-carbaldehyde oxime with copper(II) chloride,
determined by X-ray, and of the complex of 5-(4-
methylphenyl)isoxazole-3-carbaldehyde with palla-
dium(II) chloride, calculated at the B3LYP1/MIDI(3d)
level of theory [4, 22]. In particular, the bond distances
VII
Calculated structures of complexes VI and VII.
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5-(NAPHTH-1-YL)- AND 5-[(1,1'-BIPHENYL)-4-YL]ISOXAZOLE-3-CARBALDEHYDE OXIMES
1785
Table 1. Selected bond distances d, Å, and bond angles ω, deg, in complexes VI and VII
d, Å
ω, deg
Bond
Angle
VI
VII
VI
VII
Pd–Nisox
Pd–Noxime
Pd–Clа
2.126
2.123
NPdN
74.8
74.7
2.203
2.245
2.204
2.247
ClPdCl
93.5
135.9
124.0
108.0
120.9
110.5
109.0
116.7
102.8
109.7
93.6
135.9
124.0
107.8
120.9
110.7
109.2
116.7
102.8
109.5
PdNOisox
PdNОoxime
CNОisox
CNОoxime
CCNisox
CONisox
CCNoxime
CCCisox
СCОisox
C–Nisox
C–Noxime
C–Cisox
1.286
1.287
1.253
1.254
1.356–1.414
1.476
1.360–1.412
1.475
Cisox–Coxime
Cisox–Сarom
1.470
1.461
С–Сarom
N–Oisox
N–Ooxime
1.356–1.432
1.335
1.378–1.393
1.336
1.328
1.328
a Average of two values (2.444 and 2.246 Å for complex VI, 2.246 and 2.248 Å for complex VII).
in the heterocycle differ by no more than 0.05 Å. The
structure of molecules VI, VII is shown in figure, the
principal bond distances and angles are given in Table 1.
in 50% aqueous methanol at 20 and 75°С or in water
at 100°С in the presence of 0.1 mol % of palladium
complexes and potassium carbonate as a base. All
reactions were performed in air, without inert
atmosphere. Introducing the catalyst into the reaction
mixture even at room temperature led to visible change
of the original color of complexes and complete
dissolution of the suspensions after 2–3 min, so that
the reaction proceeded under homogeneous conditions.
The results of investigation of catalytic activity of
complexes VI, VII are presented in Table 4.
For the optimized structures of complexes VI, VII
the main IR frequencies were calculated and assigned.
The calculation of IR spectra was performed using the
standard procedure of GAMESS software, with scaling
factor of 0.911. The use of scaling factors in quantum
chemical calculations of IR spectra was analyzed in
detail in review [23]. The results of calculations were
interpreted using the Facio program [24, 25]. The
obtained frequencies (Tables 2, 3) are in satisfactory
agreement with the experimental data, which is
indicative of the validity of the calculated structures of
the complexes shown in figure.
As follows from these data, complexes VI, VII at
higher temperatures (75 or 100°С) show high catalytic
activity. The reactions were completed in 1–2 min with
the formation of the target 4'-methoxy[1,1'-biphenyl]-
3-carboxylic acid VIII in 98–100% yield (runs
2, 3, 5, and 6). The formed acid VIII was identified by
1Н NMR spectroscopy, the position and multiplicity of
the signals corresponded to the literature data [26].
Complexes VI, VII were tested as catalysts of the
Suzuki reaction in the form of their stable 0.005 M
suspensions in methanol. Bearing in mind the goal of
adaptating new catalysts to aqueous media and
elaboration of the basis of ecologically safe processes
we have used aqueous and aqueous-alcoholic media as
solvents for the reaction. As a model Suzuki reaction,
we have chosen the reaction of 4-methoxyphenyl-
boronic acid highly prone to protodeboronation with 3-
bromobenzoic acid. The experiments were carried out
In all experiments, no palladium black was formed
till the reaction was completed. The absence of
palladium black during the reaction confirms the
suggestion made above that Pd(0) can be stabilized by
isoxazole ligands IV, V. After the reaction, sizable
aggregates of Pd precipitated, so, the reaction can be
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 84 No. 9 2014

1786
POTKIN et al.
Table 2. Calculated and experimental values of principal
vibration frequencies in the IR spectrum of complex VI
Table 3. Calculated and experimental values of principal
vibration frequencies in the IR spectrum of complex VII
Frequency, cm–1
Frequency, cm–1
Type of vibrationsa
experi-
experi-
Type of vibrations
calculated
calculated
mental
mental
ν(О–Н)
3443
3117
3030
1608
1573
1553
1486
1446
1409
1287
1254
1201
1181
1150
3450
3109
3038
1613
1578
1543
1483
1454
1401
1291
1246
1198
1182
ν(О–Н)
3442
3053
3016
1623
1600
1530
3450
3045
3024
1622
1596
1533
ν(С–Н)arom
ν(С–Н)isox
ν(С–Н)isox + ν(С–Н)arom
ν(С=С)arom + ν(С=N)isox
ν(С=N)isox + ν(С=С)arom
ν(С=N)oxime + ν(С=С)oxime
ν(С–Н)arom
ν(С=N)isox + ν(С=С)arom
ν(С=N)isox + ν(С=С)arom
ν(С=N)oxime + ν(С–С)oxime
δ(С–Н)arom
ν(С=С)arom + δ(С=С)isox
1512
1506
δ(С–Н)arom
1470
1450
1390
1342
1270
1126
1103
1483
1442
1386
1315
1268
1130
1107
1031
994
δ(С–Н)arom
ν(С=С)arom + δ(С–Н)arom + δ(О–Н)
δ(С–Н)arom
δ(С–Н)arom + δ(О–Н)
δ(О–Н) + δ(С–Н)oxime
ν(С–О) + δ(С–Н)oxime + δ(О–Н)
δ(С–Н)arom
ν(С=С)arom
δ(С–Н)oxime + δ(О–Н)
ν(N–О)isox + δ(С–Н)oxime + δ(С–Н)isox
δ(С–Н)isox
δ(С–Н)isox + δ(С–Н)arom
ν(N–О)oxime + δ(С–Н)arom
ν(N–О)isox + δ(С–Н)isox + δ(С–Н)oxime 1116
δ(С–Н)isox 1065
ν(С–О)isox + δ(O–N–C)isox + δ(С–Н)isox 1042
1146
1122
ν(С–O)isox + δ(С–Н)arom + δ(O–N–C)isox 1027
δ(С–Н)arom
990
930
833
801
1057
1039
1013
953
δ(C–O–N)isox
936
ν(N–O) + δ(O–H)oxime
δ(С–Н)isox + δ(С–Н)arom
839
δ(С–Н)arom
1006
945
843
820
766
726
802
δ(С–О–N)isox
δ(С–С–N)isox
δ(С–Н)isox + δ(С–Н)arom
δ(С–Н)arom
δ(С–Н)isox + δ(С–Н)arom
773
777
a
836
Hereinafter the assignment is given for vibrations having largest
contribution in the vibrational frequency.
816
762
easily monitored visually. TLC monitoring of the
reaction mixtures at the moment of formation of Pd
black always showed the absence of aryl halide. The
solution remained practically colorless, which is an
indirect indication of low concentration of
colloid (nanosized) palladium in solution and in the
reaction products. Palladium black is easily separated
from the reaction products by filtration or centri-
fugation. It is noteworthy that the content of palladium
in the target products, especially when they are
supposed to be used as drugs, must not exceed 10 ppm.
δ(С–Н)isox
730
room temperature in 15–20 min with quantitative yield
(runs 1 and 4). In a comparative experiment when the
reaction was catalyzed with 0.1 mol % Na2PdCl4 the
reaction mixture turned dark immediately after
addition of the catalyst, and after 5 min palladium
black was formed. The yield of the coupling product
after 10 min was 89% (run 7). After the formation of
Pd black the reaction practically stopped and after 4 h
the yield increased only to 92%. At a higher
temperature the product of cross-coupling was formed
The activity of the complexes was very high: in
50% aqueous methanol the reaction was completed at
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5-(NAPHTH-1-YL)- AND 5-[(1,1'-BIPHENYL)-4-YL]ISOXAZOLE-3-CARBALDEHYDE OXIMES
1787
Table 4. Reaction of 3-bromobenzoic acid with 4-methoxy-
phenylboronic acid on palladium complexes VI, VIIа
quantitatively in 5 min (run 8). Note also that in all
reactions the formation of small amounts (1–2%) of
the product of homocoupling of arylboronic acid, 4,4'-
dimethoxy-1,1'-biphenyl, was observed. Since the
reactions were not carried out in an inert atmosphere,
the side product is formed, most probably, by the Pd-
catalyzed oxidation of the starting arylboronic acid by
air oxygen [27], but the contribution of this process is
small. High yields of the product of cross-coupling
observed in the model reaction with participation of
arylboronic acid allowed us to avoid further
optimization of the catalytic system with respect to the
solvent and the base.
CO2H
O
CO2H
0.1 mol % Pd
+
K2CO3,
solvent
Br
O
20_100oC
B(OH)2
VIII
Yield of VIII,
Exp. no. Pd complex T,°C b Time, min
c
%
1
2
3
4
5
6
7
VI
VI
20
75
15
2
99
100
98
The results obtained on the effective catalysis of the
Suzuki reaction by isoxazole palladium complexes in
aqueous media were used for the synthesis of biaryls
with furyl and thienyl groups, on the basis of which
new drugs are now under development [28–31]. Also,
polythiophene motif is often present in conducting
polymers [32]. However, 2-furyl- and 2-thienylboronic
acids used for their synthesis are prone to proto-
deboronation, so, their use in the Suzuki reaction is
extremely problematic [33].
VI
100
20
1
VII
20
2
100
99
VII
75
VII
100
20
1
100
Na2PdCl4
10
240
5
89
92
99
8
Na2PdCl4
100
Under the worked out conditions (0.01–0.1 mol %
of Pd complex VI or VII, 2.5 equiv. of K2CO3, for
water-insoluble aryl halides, with addition of 1 mol %
of Bu4NBr, water, 100°C), 2-furyl- and 2-thienyl-
boronic acids react with various aryl bromides contain-
ing electron-acceptor and electron-donor groups with
the formation of the corresponding heterobiaryls (IX-
XVIII) in high yields (Scheme 2).
а
ArBr (0.50 mmol), Ar'B(OH)2 (0.60 mmol), K2CO3 (1.25 mmol),
H2O + MeOH (2.5 mL each) or 5 mL H2O. b 20°С and 75°С in
aqueous methanol, 100°С in water. c Yield from 1H NMR data.
should be noted that in ethanol with catalysis with
1 mol % of the phosphine complex [Pd(OAc)2 +
2RuPhos] similar reactions proceed at 85°С only in an
inert atmosphere and are completed in 2–24 h [RuPhos
is dicyclohexyl(2',6'-diisopropylbiphen-2-yl)phosphine]
[34].
The activity of azole complexes VI and VII in
water is so high that in the case of activated aryl
bromides containing electron-withdrawing substituents,
the amount of the catalyst can be reduced by an order
of magnitude, to 0.01 mol %, practically without
changing the yield and time of the reaction. Under
these conditions, 4-bromobenzaldehyde and 5-bromo-
thiophene-2-carbaldehyde smoothly react with 2-furyl-
and 2-thienylboronic acid to afford the products of
cross-coupling in 96–98% yield. For comparison, it
By the example of the synthesis of 2-(2-furyl)-
pyridine-3-amine (XIV) we have shown principal
possibility of using more cheap hetaryl chlorides
instead of bromides. In the presence of 0.1 mol % of
complex VI the reaction of 3-amino-2-chloropyridine
with 2-furylboronic acid after 5 min gives the target
product XIV in high yield (95%). In dry dioxane, the
Scheme 2.
0.01–0.1 mol % VI or VII
2.5 equiv. K2CO3
Ar(Het)–Br
+
Ar(Het)
IX_XVIII
B(OH)2
(1 mol % Bu4NBr)
H2O, 100°C, 1–5 min
X
X
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POTKIN et al.
Scheme 3.
S
O
O
O
OHC
O
OHC
MeO
OHC
HO2C
X
IX
XI
XII
0.1 mol % VI
0.01 mol % VI
0.01 mol % VI
5 min
0.1 mol % VI
1 min
3 min
5 min
97%
98%
96%
99%
CO2H
S
CHO
N
O
S
O
NH2
XIV
N
XIII
XV
XVI
0.1 mol % VII
(from HetCl)
0.1 mol % VI
0.01 mol % VII
5 min
5 min
0.1 mol % VII
5 min
2 min
99%
95%
96%
95%
NH2
HO
S
S
XVIII
XVII
0.1 mol % VI
5 min
0.1 mol % VII
5 min
98%
97%
Scheme 4.
CO2H
0.1 mol % VI
2.5 equiv. K2CO3
CO2H
+
(HO)2B
CO2Me
CO2Me
H2O, 100°C
10 min
Br
XIX
completion of the reaction requires 18 h of reflux of
the reaction mixture, two-fold excess of 2-furylboronic
acid, and catalysis with 3 mol % of Pd[Р(t-Bu)3]2, the
yield being 88% [35] (Scheme 3).
neither case in the cross-coupling reaction, as well as
in the model reaction, palladium black was formed,
and the reaction mixtures remained practically
colorless until completion of the reaction. At the
moment of formation of aggregates of palladium black
(0.8–1.0 μm), according to TLC data, aryl(hetaryl)
halide was lacking in the reaction mixture.
A high potential of the developed catalytic system
for the synthesis of polyfunctional compounds is also
proved by the preparation of 3'-(methoxycarbonyl)-
biphenyl-2-carboxylic acid (XIX) containing the
carboxyl and ester groups in one molecule, in
preparative yield (97%) (Scheme 4).
Therefore, it was shown on a large number of
examples that oxime-isoxazole palladium complexes
are stable and efficient catalysts of the Suzuki reaction
in aqueous media with participation of hetarylboronic
acids (TON to 9800, TOF to 288000 h–1). Under the
developed conditions the reactions proceed with
Note that all of the aforementioned reactions were
performed in air without an inert atmosphere. For the
catalyst concentrations from 0.01 to 0.1 mol % in
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5-(NAPHTH-1-YL)- AND 5-[(1,1'-BIPHENYL)-4-YL]ISOXAZOLE-3-CARBALDEHYDE OXIMES
1789
practically quantitative yields, which allows to
significantly simplify the process of isolation of target
compounds.
Found, %: С 56.33; Н 2.97; Cl 35.66. C14H9Cl3O.
Calculated, %: C 56.13; H 3.03; Cl 35.50.
1-[(1,1'-Biphenyl)-4-yl]-3,4,4-trichloro-3-buten-
1-one (IV). Yield 85%, mp 87–89°С. IR spectrum,
cm–1: 3054, 3031, 2958, 2921, 2850 (СН), 1680
(С=О), 1602, 1582, 1559, 1510, 1473 (С=С), 1450
(СН), 1406, 1327, 1309, 1221, 1190, 1110, 1073, 1026
(С–С, С–О), 994, 920, 841 (C–Cl). 1Н NMR spectrum,
EXPERIMENTAL
IR spectra were taken on a Fourier spectrometer
1
Protege-460 Nikolet in KBr. Н and 13С NMR spectra
were registered on a Bruker Avance-500 spectrometer
in CDCl3 (ketones I, II) and in (CD3)2CO (isoxazoles
IV, V). Chemical shifts are referred to the residual
signals of the solvent [in CDCl3: δН = 7.26 ppm, δС =
77.2 ppm, (CD3)2CO: δН = 2.05 ppm, δС = 30.2 ppm,
(CD3)2SO: δН = 2.50 ppm, δС = 40.1 ppm].
3
(CDCl3), δ, ppm: 4.33 s (2Н, СН2), 7.43 t (1Нarom, J
7.5 Hz), 7.50 t (2Нarom, 3J 7.5 Hz), 7.64 d (2Нarom, 3J
7.5 Hz), 7.72 d (2Нarom, 3J 8.3 Hz), 8.03 d (2Нarom, 3J
8.3 Hz). 13С NMR spectrum, (CDCl3), δ, ppm: 46.31
(1С, СН2), 127.39 (2С, 2СНarom), 127.56 (2С,
2СНarom), 128.60 (1С, 1СНarom), 128.95 (2С, 2СНarom),
129.16 (2С, 2СНarom), 121.28, 125.92, 134.55, 139.63,
146.63 (5Сquart), 191.99 (1С, С=О). Found, %: С
58.88; Н 3.49; Cl 32.44. C16H11Cl3O. Calculated, %: C
59.02; H 3.41; Cl 32.66.
The residual content of palladium in the target
products was determined by atomic absorption
spectroscopy on a MGA-915 spectrometer. Melting
points were measured on a Koeffler bench. TLC was
performed on Silufol UV-254 plates, eluent hexane–
Et2O, 2 : 1. Commercial reagents and solvents
(Aldrich, Merck) were used without further purification.
5-(Naphth-1-yl)isoxazole-3-carbaldehyde oxime
(I). To the mixture of 59.6 mmol of hydroxylamine
hydrochloride and 128.8 mmol of Et3N in 50 mL of
methanol 23.8 mmol of naphthyl trichloroallyl ketone
III was added by portions, and the reaction mixture
was refluxed for 12 h, then the reaction mixture was
poured into water, acidified with HCl to pH 6, the
light-yellow precipitate was filtered off, washed with
water, and crystallized from CHCl3. Yield 85%, mp
171–172°С. IR spectrum, cm–1: 3250 (ОH), 3049,
3014, 2925, 2851 (СН), 1640, 1603, 1582, 1565, 1512
(C=N, С=С), 1446, 1435 (СН), 1393, 1286, 1110,
General procedure for the synthesis of α-naph-
thyl(p-diphenyl)trichloroallyl ketones (III, IV). To
the solution of 2.26 g (10.9 mmol) of 3,4,4-trichloro-3-
butenoyl chloride V in 30 mL of dry methylene
chloride at 10–12°С 1.46 g (10.9 mmol) of dry AlCl3
was added and the mixture was stirred for 20 min.
After that, the solution of 13.06 mmol of naphthalene
(or biphenyl) in 5 mL of methylene chloride was added
and refluxed until evolution of HCl ceased (4 h for
naphthalene and 2 h for biphenyl). After completion of
the reaction, the reaction mixture was poured onto ice,
organic layer was separated, washed with water, with
dilute solution of potassium carbonate, water, and
dried over calcium chloride. The solvent was removed
in a vacuum, solid residue was crystallized from
ethanol.
1
1020, 987 (С–С, С–О). Н NMR spectrum, (acetone-
d6), δ, ppm: 7.06 s (1Н, СНisox), 7.64 m (3Нarom), 7.91
d (1Нarom. 3J 7.4 Hz), 8.04 d (1Нarom. 3J 7.4 Hz), 8.11 d
(1Нarom, 3J 8.2 Hz), 8.30 d (1Нarom, 3J 8.2 Hz), 8.32 s
(1H, CH=NOH). 13С NMR spectrum, (acetone-d6), δ,
ppm: 101.76 (1С, СНisox), 125.91 (1С, СНarom), 126.53
(1С, СНarom), 127.80 (1С, СНarom), 128.85 (1С,
СНarom), 129.16 (1С, СНarom), 130.00 (1С, СНarom),
132.40 (1С, СНarom), 140.81 (1С, CH=NOH), 128.29,
131.36, 135.13, 160.31, 171.23 (5Сquart). Found, %: С
70.49; Н 4.52; N 11.71. C14H10N2O2. Calculated, %: C
70.58; H 4.23; N 11.76.
1-(Naphth-1-yl)-3,4,4-trichloro-3-buten-1-one (III).
Yield 80%, mp 97–98°С. IR spectrum, cm–1: 3064,
3067, 3046, 2962, 2923, 2854 (СН), 1681 (С=О),
1610, 1580, 1557, 1507 (С=С), 1436 (СН), 1413,
1303, 1232, 1204, 1175, 1090, 1079 (С–С, С–О), 922,
912, 805 (C–Cl). 1Н NMR spectrum, (CDCl3), δ, ppm:
3
4.37 s (2Н, СН2), 7.52 t (1Нarom, J 7.7 Hz), 7.56 t
5-[(1,1'-Biphenyl)-4-yl]isoxazole-3-carbaldehyde
oxime (II) was prepared similarly but the reaction was
performed in ethanol. Yield 40%, mp 172–174°С. IR
spectrum, cm–1: 3221 (ОH), 3055, 3025, 2923, 2853
(СН), 1633, 1614, 1599, 1581, 1553, 1523 (C=N,
С=С), 1483, 1439 (СН), 1406, 1273, 1113, 1072,
3
3
(1Нarom, J 7.4 Hz), 7.63 t (1Нarom, J 7.7 Hz), 7.89 t
3
3
(2Нarom, J 7.4 Hz), 8.04 d (1Нarom, J 8.2 Hz), 8.69 d
3
(1Нarom, J 8.2 Hz). 13С NMR spectrum, (CDCl3), δ,
ppm: 49.16 (1С, СН2), 124.38, 125.78, 126.93, 128.14,
128.59, 128.67, 133.83 (7С, 7СНarom), 121.47, 125.98,
126.14, 130.37, 134.15 (5Сquart), 196.11 (1С, С=О).
1
1050, 1025, 994 (С–С, С–О). Н NMR spectrum,
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 84 No. 9 2014

1790
POTKIN et al.
(acetone-d6), δ, ppm: 7.11 s (1Н, СНisox), 7.40 t
(1Нarom, 3J 7.4 Hz), 7.49 t (2Нarom, 3J 7.4 Hz), 7.72 d
(2Нarom, 3J 7.4 Hz), 7.81 d (2Нarom, 3J 8.5 Hz), 7.99 d
(2Нarom, 3J 8.5 Hz), 8.26 s (1H, CH=NOH), 11.24 br.s
(1Н, ОН). 13С NMR spectrum, (acetone-d6), δ, ppm:
97.86 (1С, СНisox), 127.53 (2С, 2СНarom), 128.08 (2С,
2СНarom), 128.72 (2С, 2СНarom), 129.21 (1С, 1СНarom),
130.20 (2С, 2СНarom), 127.12, 127.49, 144.07, 160.58,
170.82 (5Сquart), 140.87 (1С, CH=NOH). Found, %: С
73.04; Н 4.69; N 10.55. C16H12N2O2. Calculated, %: C
72.72; H 4.58; N 10.60.
sample the reaction mixture was diluted with water,
heated, filtered to remove small amounts (~0.01–
0.1 mol %) of palladium black, 10–15 % v/v of alcohol
was added, the mixture was heated to ~50°C and
slowly acidified with 5% HCl to pH 2–3 at stirring. As
a result, easily filtered precipitates were formed, and
analytically pure samples were obtained without using
chromatographic methods. In the case of water-
insoluble heterobiaryls, the reaction mixture was
diluted with saturated solution of NaCl, extracted with
Et2O or EtOAc, the extract was dried over Na2SO4 and
filtered through small layer of silica gel. The solvent
was removed on a rotary evaporator, the residue, as a
rule, had purity of no less than 99%. Analytically pure
samples were obtained by crystallization of
heterobiaryls from minimal amount of aqueous alcohol
(10–20% Н2О) or by transformation of amines into
hydrochlorides. The characteristics of the synthesized
compounds are presented below.
General procedure for preparation of complexes
VI, VII. To the solution of 0.2 mmol of the
corresponding ligand in 10 mL of methanol at 20°С
10 mL (0.2 mmol) of 0.02 M solution of Na2PdCl4 in
methanol was added dropwise while stirring. Upon
mixing, dark-brown color of the solution of Na2PdCl4
instantly turned orange, and stable fine-crystalline
suspension of the complex was formed. The mixture
was stirred for 10 min, the solvent was removed on a
rotary evaporator, solid product was washed with
water (3 × 2 mL), and dried in a vacuum.
4-(2-Furyl)benzoic acid (IX). White crystals, mp
1
231–232°C (mp 230–232°C [36]). H NMR spectrum
3
(DMSO-d6–CDCl3, 1 : 3), δ, ppm: 6.65 d.d (1Hfuran, J
3
3
3.4 Hz, J 1.8 Hz), 7.15 d (1Hfuran, J 3.4 Hz), 7.81 m
Complex VI. Yield 96%. Found, %: C 40.68; H
2.34; Cl 17.29; N 6.82; Pd 25.36 C14H10Cl2N2O2Pd.
Calculated, %: C 40.46; H 2.43; Cl 17.06; N 6.74; O
7.70; Pd 25.61
3
(2Harom, 1Нfuran), 7.98 д (2Harom, J 8.5 Hz), 12.90 br.s
(1H, COOH). 13C NMR spectrum (DMSO-d6–CDCl3,
1 : 3), δ, ppm: 104.8 (1СНfuran), 108.9 (1СНfuran), 128.4
(2СНarom), 130.2 (2СНarom), 141.8 (1СНfuran), 125.3,
133.3, 154.6 (3Сquart), 171.1 (1С, COOH).
Complex VII. Yield 97%. Found, %: C 43.73; H
2.79; Cl 16.27; N 6.41; Pd 248.19 C16H12Cl2N2O2Pd.
Calculated, %: C 43.52; H 2.74; Cl 16.06; N 6.34; Pd
24.10.
4-(2-Furyl)benzaldehyde (X). Light-yellow crystals,
mp 43–44°C (mp 42–44°C [37]). IR spectrum, cm–1:
3018, 2917, 2849, 1696, 1608, 1565, 1476, 1215,
Suzuki reaction catalyzed by isoxazole palladium
complexes VI and VII (general procedure). To the
mixture of 1.2 mmol of hetarylboronic acid, 1.0 mmol
of aryl(hetaryl) bromide, 3.2 mg (0.01 mmol) Bu4NBr
(for water-insoluble aryl halides), and 0.35 g
(2.5 mmol) of K2CO3 in 5 mL Н2О preheated to 80°С,
0.1 mL of suspension of complexes VI or VII (0.01–
0.1 mol % Pd) in methanol (0.001–0.01 М) was added.
The reaction mixture was placed in a silicone bath
preheated to 150°С and was refluxed with vigorous
stirring to complete conversion (amount of catalyst,
reaction time and yields of the products are given in
the schemes of reactions). The reaction was monitored
by TLC (eluent hexane–Et2O, 3 : 1). In the case of
activated aryl bromides the reaction was very
exothermic, so that in scaled syntheses an effective
condenser must be used.
1
1169, 1012. H NMR spectrum (CDCl3), δ, ppm: 6.52
3
3
3
d.d (1Hfuran, J 3.3 Hz, J 2.0 Hz), 6.83 d (1Hfuran, J
3.3 Hz), 7.54 d (1Hfuran, 3J 2.0 Hz), 7.79 d.d (2Harom, 3J
4
3
4
8.0 Hz, J 2.5 Hz), 7.88 d.d (2Harom, J 8.0 Hz, J
2.0 Hz), 9.99 s (1H, CHO). 13C NMR spectrum
(CDCl3), δ, ppm: 108.1 (1СНfuran), 112.2 (1СНfuran),
123.8 (2CНarom), 130.3 (2CНarom), 143.6 (1CНfuran),
134.8, 136.0, 152.5 (3Cquart), 191.5 (CHO).
5-(2-Furyl)thiophene-2-carbaldehyde (XI). Light-
orange powder, mp 39–40°C (mp 38°C [38]). 1H NMR
spectrum (CDCl3), δ, ppm: 6.49 d.d (1Hfuran, 3J 3.4 Hz,
3J 1.9 Hz), 6.77 d (1Hfuran
,
3J 3.4 Hz), 7.32 d
3
3
(1Hthiophene, J 4.0 Hz), 7.50 (1Hfuran, J 1.9 Hz), 7.70
3
(1Hthiophene, J 4.0 Hz), 9.91 s (1H, CHO). 13C NMR
spectrum (CDCl3), δ, ppm: 108.8 (1СНfuran), 112.4
(1СНfuran), 123.0 (1СНthiophene), 137.3 (1СНthiophene),
143.6 (1СНfuran), 141.6, 142.4, 148.3 (3Cquart), 182.7
(CHO).
When the products of the reaction were aryl
(hetaryl)benzoic acids, to obtain an analytically pure
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5-(NAPHTH-1-YL)- AND 5-[(1,1'-BIPHENYL)-4-YL]ISOXAZOLE-3-CARBALDEHYDE OXIMES
1791
2-(2-Furyl)pyridine-3-amine (XIV) [35]. Light-
REFERENCES
1
yelow oil. H NMR spectrum (CDCl3), δ, ppm: 4.52
br.s (2H, NH2), 6.56 d.d (1Hfuran, 3J 3.4 Hz, 3J 1.8 Hz),
1. Metal-Catalyzed Cross-Coupling Reactions, de Meijere, A.
and Diederich, F., Eds., 2nd ed., New York: Wiley-
VCH, 2004.
2. Topics in Current Chemistry: Cross-Coupling Reac-
tions: A Practical Guide, Miyaura, N., Ed., Heidelberg:
Springer, 2002, vol. 219.
3. Handbook of Organopalladium Chemistry for Organic
Synthesis, Negishi, E., Ed., New York: Wiley, 2002,
vols. 1, 2.
3
3
6.97 d (1Hfuran, J 3.3 Hz), 7.02 d.d (1Hpyridine, J
4
3
3
9.4 Hz, J 1.9 Hz), 7.17 d.d (1Hpyridine, J 9.4 Hz, J
3
4.2 Hz), 7.40 d (1Hfuran, J 1.8 Hz), 7.91 d.d (1Hpyridine
,
3J 4.2 Hz, J 1.9 Hz). C NMR spectrum (CDCl3), δ,
ppm: 107.8 (1CНfuran), 110.5 (1CНfuran), 122.3
(1CНpyridine), 123.6 (1CНpyridine), 141.9 (1CНfuran), 142.7
(1CНpyridine); 138.5, 139.7, 151.2 (3Сquart).
4
13
4. Potkin, V.I., Bumagin, N.A., Zelenkovskii, V.M.,
Petkevich, S.K., Zubenko, Yu.S., Livantsov, M.V.,
Belov, D.S., Dokl. Nats. Akad. Nauk Belarus., 2011,
vol. 55, no. 5, p. 52.
5. Potkin, V.I., Bumagin, N.A., Petkevich, S.K., Lya-
khov, A.S., Rudakov, D.A., Livantsov, M.V., and
Golantsov, N.E., Synthesis, 2012, vol. 44, no. 1, p. 151.
6. Bumagin, N.A., Petkevich, S.K., Kletskov, A.V.,
Livantsov, M.V., Golantsov, N.E., and Potkin, V.I.,
Chem. Heterocycl. Comp., 2013, vol. 49, no. 10,
p. 1515.
2-(2-Thienyl)benzoic acid (XV). Flesh-colored
1
crystals, mp 98°C (mp 95–97°C [39]). H NMR spec-
trum (DMSO-d6–CDCl3, 1 : 3), δ, ppm: 7.08 m
3
3
(2Hthiophene), 7.36 d.d (1Hthiophene, J 4.9 Hz, J 1.3 Hz),
3
13
7.70 m (3Harom), 7.89 d (1Harom, J 7.6 Hz). C NMR
spectrum (DMSO-d6–CDCl3, 1 : 3), δ, ppm: 126.1.
(1CНthiophene), 126.9 (1CНthiophene), 127.3 (1CНthiophene),
127.9 (1CНarom), 130.6 (1CНarom), 131.8 (1CНarom),
132.0 (1CНarom), 130.2, 135.3, 141.7 (3Cquart), 171.1
(COOH).
7. Potkin, V.I., Bumagin, N.A., Petkevich, S.K., Klets-
kov, A.V., Zubenko, Yu.S., Golantsov, N.E., Livan-
tsov, M.V., Belov, D.S., and Veselov, I.S., Dokl. Nats.
Akad. Nauk Belarus., 2013, vol. 57, no. 1, p. 67.
8. Kashin, A.N., Bumagina, I.G., Bumagin, N.A.,
Bakunin, V.N., and Beletskaya, I.P., Zh. Org. Khim.,
1981, vol. 17, no. 1, p. 905.
9. Bumagin, N.A., Kalinovskii, I.O., Ponomarev, A.B.,
and Beletskaya, I.P., Dokl. Akad. Nauk SSSR, 1982,
vol. 265, no. 5, p. 1138.
2-(2-Thienyl)aniline (XVIII). Light-brown powder,
mp 37–38°C (mp 35–37°C [40]). IR spectrum, cm–1:
3451, 3373, 3069, 2992, 2924, 1615, 1488, 1452,
1
1304, 1204, 1158, 955, 848, 751, 703. H NMR
spectrum (CDCl3), δ, ppm: 3.96 br.s (2H, NH2), 6.79
m (2Harom), 7.14 m (1Harom, 1Нthiophene), 7.19 d
3
3
(1Hthiophene, J 3.1 Hz), 7.28 d (1Harom, J 7.6 Hz), 7.32
3
13
d (1Hthiophene, J 5.3 Hz). C NMR spectrum (CDCl3),
δ, ppm: 115.9 (1CНarom), 118.5 (1CНarom), 125.2
(1CНthiophene), 125.8 (1CНthiophene), 127.5 (1CНthiophene),
129.1 (1CНarom), 131.0 (1CНarom), 120.0, 141.5, 144.0
(3Cquart).
10. Bumagin, N.A., Bumagina, I.G., and Beletskaya, I.P.,
Dokl. Akad. Nauk SSSR, 1984, vol. 274, no. 4, p. 818.
11. Bumagin, N.A., Gulevich, Y.V., and Beletskaya, I.P.,
J. Organomet. Chem., 1985, vol. 282, no. 3, p. 421.
12. Bumagin, N.A., Gulevich, Y.V., and Beletskaya, I.P.,
2-(4-Methoxyphenyl)furan (XII) [40], 5-(3-
pyridyl)furan-2-carbaldehyde (XIII) [42], 4-(2-
thienyl)benzaldehyde (XVI) [43], 3-(2-thienyl)
phenol (XVII) [44] and 2-(3'-methoxycarbonyl)
biphenyl-2-carboxylic acid (XIX) [45] are known
compounds, physicochemical characteristics of the
obtained products correspond to the literature data.
J. Organomet. Chem., 1985. Т. 285, nos. 1–3, p. 415.
13. Bumagin, N.A., Ponomaryov, A.B., and Beletskaya, I.P.,
J. Organomet. Chem., 1985, vol. 291, no. 1, p. 129.
14. Bykov, V.V. and Bumagin, N.A., Russ. Chem. Bull.,
1997, vol. 46, no. 7, p. 1344.
15. Bumagin, N.A. and Tsarev, D.A., Tetrahedron Lett.,
1998, vol. 39, no. 44, p. 8155.
ACKNOWLEDGMENTS
16. Shishkina, I.N., Dotsenko, I.A., Demyanovich,V.M.,
Bumagin, N.A., and Zefirov, N.S., Dokl. Chem., 2012,
vol. 445, part 2, p. 166.
17. Bumagin, N.A., Veselov, I.S., and Belov, D.S., Chem.
Heterocycl. Comp., 2014, vol. 50, no. 1, p., 19.
18. Huzinaga, S., Andzelm, J., and Klobukowski, M.,
Gaussian Basis Sets for Molecular Calculations,
Amsterdam: Elsevier, 1984.
This work was performed with the financial support
from the Russian Foundation for Basic Research
(grants nos. 12-08-90025-Bel_а and 14-08-90012-
Bel_а) and by Belarus’ Republic Foundation for
Fundamental Research (grants nos. Х12Р-024 and
Х14Р-003).
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 84 No. 9 2014

1792
POTKIN et al.
19. Ol’dekop, Yu.A, Kaberdin, R.V.,and Zhidkov, Yu.N.,
Yang, H., Czabotar, P.E., Fairlie, W.D., Lee, E.F.,
Adams, J.M., Chen, L., van Delft, M.F., Lowes, K.N.,
Wei, A., Huang, D.C.S., Colman, P.M., Street, I.P.,
Baell, J.B., Watson, K., and Lessene, G., J. Med. Chem.,
2013, vol. 56, no. 13, p. 5514.
Zh. Org. Khim., 1978, vol. 14, no. 3, p. 484.
20. Potkin, V.I., Kaberdin, R.V., Petkevich, S.K., and
Kurman, P.V., Russ. J. Org. Chem., 2002, vol. 38, no. 8,
p. 1099.
32. Inzelt, G., Conducting Polymers: A New Era in
21. Petkevich, S.K., Potkin, V.I., and Kaberdin, R.V., Russ.
Electrochemistry, New York: Springer, 2012.
J. Org. Chem., 2004, vol. 40, no. 8, p. 1146.
33. Kinzel, T., Zhang, Y., and Buchwald, S. L., J. Am.
Chem. Soc., 2010, vol. 132, no. 40, p. 14073.
22. Shakirova, O.G., Kurat’eva, N.V., Lavrenova, L.G.,
Bogomyakov, A.S., Petkevich, S.K., and Potkin, V.I.,
Russ. J. Struct. Chem., 2010, vol. 51, no. 4, p. 703.
34. Molander, G.A., Canturk, B., and Kennedy, L.E.,
J. Org. Chem., 2009, vol. 74, no. 3, p. 973.
23. Scott, A.P. and Radom, L., J. Phys. Chem., 1996,
vol. 100, no. 41, p. 16502.
35. Read, M.L., Krapp, A., Miranda, P.O., and Gunder-
sen, L.-L., Tetrahedron, 2012, vol. 68, no. 7, p. 1869.
24. Suenaga, M., J. Comput. Chem. Jpn., 2005, vol. 4, no. 1,
p. 25.
36. Korolev, D.N. and Bumagin, N.A., Tetrahedron Lett.,
2005, vol. 46, no. 34, p. 5751.
25. Suenaga, M., J. Comput. Chem. Jpn., 2008, vol. 7, no. 1,
37. Marinozzi, M., Carotti, A., Sansone, E., Macchiarulo, A.,
Rosatelli, E., Sardella, R., Natalini, B., Rizzo, G.,
Adorini, L., Passeri, D., De Franco, F., Pruzanski, M.,
and Pellicciari, R., Bioorg. Med. Chem., 2012, vol. 20,
no. 11, p. 3429.
p. 33.
26. Fort, Y., Leleu, A., and Schneider, R., Adv. Synth.
Catal., 2006, vol. 348, no. 9, p. 1086.
27. Zhou, Z., Hu, Q., Du, Z., Xue, J., Zhang, S., and Xie, Y.,
Synth. React. Inorg., Met.-Org., Nano-Met. Chem.,
2012, vol. 42, no. 7, p. 940.
28. Pomel, V., Klicic, J., Covini, D., Church, D.D., Shaw, J.P.,
Roulin, K., Burgat-Charvillon, F., Valognes, D., Camps, M.,
Chabert, C., Gillieron, C., Françon, B., Perrin, D.,
Leroy, D., Gretener, D., Nichols, A., Vitte, P.A.,
Carboni, S., Rommel, C., Schwarz, M.K., and Rückle, T.,
J. Med. Chem., 2006, vol. 49, no. 13, p. 3857.
29. Villain-Guillot, P., Gualtieri, M., Bastide, L., Roquet, F.,
Martinez, J., Amblard, M., Pugniere, M., and Leonetti, J.P.,
J. Med. Chem., 2007, vol. 50, no. 17, p. 4195.
30. Katritzky, A.R., Tala, S.R., Lu, H., Vakulenko, A.V.,
Chen, Q.-Y., Sivapackiam, J., Pandya, K., Jiang, S., and
Debnath, A.K., J. Med. Chem., 2009, vol. 52, no. 23,
p. 7631.
38. Ismail, M.A., J. Chem. Res., 2006, no. 11, p. 733.
39. Solbakken, M. and Skramstad, J. Acta Chem. Scand.,
1993, vol. 47, no. 12, p. 1214.
40. Smith, P.A.S. and Boyer, J.H., J. Am. Chem. Soc., 1951,
vol. 73, no. 6, p. 2626.
41. Buchwald, S.L. and Naber, J.R., Adv. Synth. Catal.,
2008, vol. 350, nos. 7–8, p. 957.
42. Kim, S.-H. and Rieke, R.D., J. Org. Chem., 2013,
vol. 78, no. 5, p. 1984.
43. Baghbanzadeh, M., Kappe, C.O., and Pilger, C., J. Org.
Chem., 2011, vol. 76, no. 19, p. 8138.
44. Rumyantsev, A.N., Terenin, V.I., and Yudin, L.G.,
Chem. Heterocycl. Comp., 1986, vol. 22, no. 3, p. 300.
45. Li, Y., Ding, Y.-J., Wang, J.-Y., Su, Y.-M., and Wang, X.-S.,
31. Sleebs, B.E., Kersten, W.J.A., Kulasegaram, S.,
Org. Lett., 2013, vol. 15, no. 3, p. 2574.
Nikolakopoulos, G., Hatzis, E., Moss, R.M., Parisot, J.P.,
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