Synthesis of E-1-(alkoxy-NNO-azoxy)-2-arylethenes by the reaction of bis(alkoxy-NNO-azoxy)methanes with benzyl halides under conditions of phase-transfer catalysis

Article abstract of DOI:10.1134/S1070428013050072

Reaction of bis(methoxy- and ethoxy-NNO-azoxy)methane with benzyl halides and alkali under the conditions of a phase-transfer catalysis furnishes in one stage E-1-(alkoxy-NNO-azoxy)-2-arylethene in 21-55% yields. The intermediate products, 1,1-bis(alkoxy-NNO-azoxy)-2-arylethanes under the action of alkali eliminate one of the two alkoxy-NNO-azoxy groups with the formation of a double bond. The optimum solvent is DMSO, and as benzyl halides, benzyl chlorides. In the case of 4-bromobenzyl bromide a formation was found of a side bisbenzylation product, 1,3-bis(4-bromophenyl)-2,2-bis(methoxy-NNO-azoxy)propane.

Full text of DOI:10.1134/S1070428013050072

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2013, Vol. 49, No. 5, pp. 678−685. © Pleiades Publishing, Ltd., 2013.
Original English Text © I.N. Zyuzin, 2013, published in Zhurnal Organicheskoi Khimii, 2013, Vol. 49, No. 5, pp. 697−703.
Synthesis of E-1-(Alkoxy-NNO-azoxy)-2-arylethenes
by the Reaction of Bis(alkoxy-NNO-azoxy)methanes
with Benzyl Halides under Conditions
of Phase-Transfer Catalysis
I. N. Zyuzin
Institute of Problems of Chemical Physics, Russian Academy of Sciences
Chernogolovka, Moscow oblast, 142432 Russia
e-mail: zyuzin@icp.ac.ru
Received April 19, 2012
Abstract—Reaction of bis(methoxy- and ethoxy-NNO-azoxy)methane with benzyl halides and alkali under the
conditions of a phase-transfer catalysis furnishes in one stage E-1-(alkoxy-NNO-azoxy)-2-arylethene in 21–55%
yields. The intermediate products, 1,1-bis(alkoxy-NNO-azoxy)-2-arylethanes under the action of alkali eliminate
one of the two alkoxy-NNO-azoxy groups with the formation of a double bond. The optimum solvent is DMSO,
and as benzyl halides, benzyl chlorides. In the case of 4-bromobenzyl bromide a formation was found of a side
bisbenzylation product, 1,3-bis(4-bromophenyl)-2,2-bis(methoxy-NNO-azoxy)propane.
DOI: 10.1134/S1070428013050072
Alkoxy-NNO-azoxy compounds are known since the
end of nineteenth century [1, 2]. Methods of their synthe-
sis along with the other azoxy compounds are summa-
rized in reviews [3–5]. Unsaturated alkoxy-NNO-azoxy
compounds are less understood [6–17]. Alkoxy-NNO-
azoxy compounds with a double or a triple bond both in
the alkoxy group [7–9, 14] and in the substituent at the
N-oxide nitrogen atom are known. The most interesting
among the latter are α,β-unsaturated alkoxy-NNO-azoxy
compounds [6, 12, 13, 15–17], since the reactions at
the activated double bond (Michael reaction etc.) open
wide opportunities for the synthesis of new alkoxy-
NNO-azoxy compounds [18–20]. The first examples of
α,β-unsaturated alkoxy-NNO-azoxy- compounds were
described in [6], but the reaction conditions, yields, and
properties of the compounds were not reported. The final
methoxy-NNO-azoxyolefin Vа was obtained by pyrolysis
of an intermediate product IIIa which in its turn was syn-
thesized from compound I by two independent methods
of four stages.
O
O
O
O
OMe
OMe
OMe
OMe
OMe
Ph
Ph
Ph
N N
N N
N N
N N
PhCHO
MeONa
Et3N
Ac2O
N
N
N
N
N
N
AcO
Ph
N
N
HO
OMe
OMe
OMe
O
O
O
O
O
I
_
H2 Pd
(1) MeONa__NO
(2) H2O_OH
(3) AgNO3
(4) MeI
O
OMe
OMe
Ph
Ph
N N
Δ
N
OMe
N
Ph
N
N
O
Va
O
IIIa
678

SYNTHESIS OF E-1-(ALKOXY-NNO-AZOXY)-2-ARYLETHENES
679
We attempted formerly to synthesize compound IIIа
by direct С-benzylation of compound I [12]. However
in the course of the reaction formed at once the target
olefin Vа (yield 46%), i.e., we succeeded to reduce the
number of stages from five to one. Analogously ethyl
homolog VIa was obtained in a 42% yield. In this report
we describe the extension of the discovered reaction to the
other benzyl halides aiming at the synthesis of 1-(alkoxy-
NNO-azoxy)-2-arylethenes with various substituents in
the aromatic ring.
O
O
O
OR
OR
O
N
N
Ar
N
N
OR
NaOH
NaOH
N
ArCH2X
N
DMSO
DMSO
N N
N N
Ar
OR
OR
O
IIIа_IIIg, IVа, IVb
I, II
Vа_Vg, VIа, VIb
R = Me (I, III, V), Et (II, IV, VI); Ar = Ph (а), 2-FC6H4 (b), 2-ClC6H4 (c), 4-ClC6H4 (d), 2,4-Cl2C6H3 (e), 4-BrC6H4 (f),
1-C10H7 (g).
In the first stage of the reaction monobenzylated prod-
ucts were formed which were easily detected by TLC,
within initial 10–15 min their amount prevailed over that
of the final arylethenes V, VI, and after ~1 h they nearly
totally disappeared. A direct proof of the assumed route
may serve one experiment where we succeeded beside
arylethene Vb to isolate and characterize the intermediate
product IIIb. This run was distinguished from the others
by the replacement of DMSO as solvent by chloroform.
The formation of arylethenes V, VI from monobenzyl de-
rivatives under the action of alkali in DMSO was proved
by a separate experiment by an example of the synthesis
of arylethene Vb from compound IIIb. Initial compound
IIIb completely reacted with alkali within 5 min, and the
yield of compound Vb was 52%.
The attempt to bring into the reaction 4-nitrobenzyl
chloride was unsuccessful. Tarring was observed with the
formation of reduction products of the nitro group owing
to the oxidation (probably, partial) of the CH2 group. At
the acidification of the reaction mixture a yellow crystal-
line sparingly soluble substance was isolated in a 15%
yield whose elemental analysis suggested that it was a
mixture of compounds VIII and IX.
In reactions of compounds I and II with benzyl
chlorides in comparable conditions (DMSO) the yields
of the corresponding arylethenes varied from 21 (Ve) to
55% (Vg). The presence of the Cl atom in the position
2 of the ring of the benzyl halide significantly reduced
the yield of the corresponding arylethene from 46 to
29% (Vа, Vc) and from 48 to 21% (Vd, Ve). It is ap-
parently due to steric hindrances at the first stage of the
benzylation. However in the reaction of compound I with
1-chloromethylnaphthalene (with steric hindrances com-
parable with 2-chloro and 2,4-dichlorobenzyl chlorides)
the yield of arylethene Vg reached 55%, and calculated
It is preferable to use the benzyl chlorides as benzyl
halides for they are as a rule more available. Beside in
the test runs applying benzyl bromides and iodides side
products were formed difficult to separate from the target
compounds. In particular, in the synthesis of arylethene
Vf (yield 40%) we succeeded to isolate the bisbenzylation
product, 1,3-bis(4-bromophenyl)-2,2-bis-(methoxy-
NNO-azoxy)propane (VII) in 5% yield (10% with respect
to 4-bromobenzyl bromide).
O2N
Cl
CO2H
NaOH
DMSO
Vе
N
VIII
N
O
OMe
HO2C
IIIе
I
N
N
N
N
Br
Br
O
N
CO2H
+
N
OMe
O
VII
HO2C
IX
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 49 No. 5 2013

ZYUZIN et al.
680
on the reacted compoundе I, 78%. The replacement of H
for F in the position 2 of the ring of the benzyl chloride
also did not reduce the yield of arylethene VIb (48%)
compared to VIа (42%).
of intermediate products III, IV into arylethenes V, VI
involves the deprotonation of the central carbon atom
giving anion А followed by a proton migration and the
formation of arylethenes V, VI through the elimination
of anion C from anion B.
One of probable mechanisms of the transformation
O
O
OR
OR
OH_
Ar
H2C
Ar
N
N
_
N
N
N
N
N
N
_
III, IV
C
HC CH
OR
OR
O
O
А
B
ArCH2Br
O
N
VII
O_
N
OR
OR
N
N
Ar
V, VI
C
H2O
_OH _
ROH + N2O
Anion of Z-alkyl hyponitrite C is apparently unstable
in the presence of water and decomposes into alcohol
and nitrous oxide. This is presumably the cause of the
vigorous gas liberation during the reaction, but a part
of gas may also form from the side reaction of the
decomposition of the geminal bisalkoxy-NNO-azoxy
compounds I–IV under the action of alkali [21]. The
formation of anion B is facilitated by the contiguous
aryl but still its fraction in the equilibrium mixture of
anions А and B should be very small. Therefore the
mechanisms are also possible including the elimination
of the monoester of Z-hyponitrous acid from anion А
through a cyclic transition state D followed by the pro-
tonation with water of intermediate E or the intermediate
formation of carbene F stabilized by the adjacent group
N(O)=NOR (valence scheme G).
O
OR
_
H
OR
Ar
H
HO
N
N
N
OR
C N
C
А
+
N
N
CH C
N N_
OR
Ar
O
E
O
_OH _
H2O
ROH + N2O
ArCH2
D
V, VI
C_
O
ArCH2
C
N N
А
N N
_C
+
OR
OR
O
G
F
V, VI
The structure of compounds IIIb, Vа–Vg, VIа, VIb,
VII was proved by the elemental analysis and H and
13C NMR spectra, and for compound Vc, VIb it was
confirmed also by mass spectra.
1
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SYNTHESIS OF E-1-(ALKOXY-NNO-AZOXY)-2-ARYLETHENES
681
1
and 125.7 MHz respectively) from 5% solutions in CDCl3
if not the other indicated, internal reference TMS. Mass
spectra were taken on an instrument MKh-1320 (EI,
70 eV). Elemental analysis was carried out on a CHNS
analyzer vario MICRO cube save compounds IIIb, Vb,
VIb whose analysis was performed manually. The melting
points were measured in open capillaries at the heating
rate ~0.5 deg/min. The qualitative analysis was carried
out by TLC on Silufol UV-254 plates, development under
UV irradiation. The following reagents were utilized:
DMSO of the chemically pure grade, triethylbenzyl
ammonium chloride (TEBA-Cl) of pure grade, silica
gel Silpearl 8–10 μm Chemapol or 40–60 μm Sapelko.
2-Fluorobenzyl chloride was preliminary distilled, the
other benzyl halides of Lancaster were used without
distillation. The concentrated water solution of alkali
(47.67%, 11.92 mmol/g) was prepared from NaOH
of pure for analysis grade. Bis(methoxy-NNO-azoxy)
methane (I) [8, 29] and bis(ethoxy-NNO-azoxy)methane
(II) [8] were prepared by known procedures.
The H NMR spectra of all new compounds are
totally consistent with the assumed structure. The
Z-configuration of the azoxy fragments is determined by
the Z,Z-structure of the initial compounds I, II [22–25],
and the E-configuration of the C=C fragment is unam-
biguously confirmed by the spin-spin coupling constants
of the olefin protons (3J 13.5–13.9 Hz) in the spectra of
arylethenes Vа–Vg, VIа, VIb (cf. [15]). In the concen-
trated mother liquors Z-isomers of arylethenes were not
1
found by the H NMR method since their fraction did
not exceed 1–2%. In the 1H NMR spectra of compounds
Vа–Vg, VIа, VIb the proton signals ofArCH= are about
twice broadened compared with the signals of protons
=CHN. This effect is presumably due to the unresolved
splitting of the proton signals ArCH= on the H and F
nuclei located in the ortho-position of the aromatic ring
(4JHF ~0.3 Hz).
In the 13C NMR spectra (5% solutions in CDCl3) of
compounds Vа–Vg the characteristic signals of MeO
groups appear in a very narrow range δ 61.81–61.99
ppm (cf. [16, 18, 26, 27]). It was noted in [26] that in
the 13C NMR spectrum of methoxy-NNO-azoxybenzene
the signal of the carbon atom linked to the N-oxide frag-
ment of the group N(O)=NOMe was more than tenfold
broadened. This effect, observed also in nitro compounds
is apparently caused by the quadruple effect of the con-
tiguous 14N nuclei. In the spectra of compounds Vа–Vg,
VIа, VIb the signal =CHN was 3–6-fold broader than the
other signals, i.e., the effect was less pronounced com-
pared to methoxy-NNO-azoxybenzene, but several times
stronger than in the geminal bis(methoxy-NNO-azoxy)
alkanes where the factor of broadening was within the
limits 1.3–1.8 [27]. The broadened signals of the atoms
=CHN are easy to identify.
E-1-(Methoxy-NNO-azoxy)-2-phenylethene (Va)
1
[12]. H NMR spectrum, δ, ppm: 4.170 s (3H, MeO),
7.368–7.410 m (3H, HP3, 4,5), 7.463 d (1H, =CHN,
h
J 13.8 Hz), 7.471–7.490 m (2H, HP2, 6), 7.738 br.d (1H,
h
PhCH=, J 13.8 Hz) (ср. [6, 12]). 13C NMR spectrum, δ,
ppm: 61.81 (1C, CH3O, Δν1/2 1.5 Hz), 127.90 (2C, Ph),
129.04 (2C, Ph), 129.10 br.s (1C, =CHN, Δν1/2 ~5.5 Hz),
129.89 (1C), 130.02 (1C), 132.08 (1C). Found, %:
C 60.89; H 5.69; N 15.71. C9H10N2O2. Calculated, %:
C 60.66; H 5.66; N 15.72.
E-1-(Ethoxy-NNO-azoxy)-2-phenylethene (VIa)
[12]. 1H NMR spectrum, δ, ppm: 1.446 t (3H, CH3CH2O,
J 7.1, Δν1/2 1.7 Hz), 4.449 q (2H, CH3CH2O, J 7.1 Hz),
7.347–7.406 m (3H, HP3, 4,5), 7.471 d (1H, =CHN, J 13.9,
h
In the mass spectra of compounds Vc, VIa [12], and
VIb the fragmentation occurs in agreement with the
published data [15, 28]. In particular, the strong peaks of
ions [M]+, [M – R]+, and [M – RNO]+ are similar to the
most intense peaks in the spectrum of methoxy-NNO-
azoxyethene [15].
Δν1/2 4.8 Hz), 7.472–7.504 m (2H, HP2, 6), 7.735 br.d
h
(1H, PhCH=, J 13.9 Hz) (ср. [12]). 13C NMR spectrum,
δ, ppm: 14.54 (1C, CH3CH2O), 70.77 (1C, CH3CH2O),
127.87 (2C, Ar), 129.02 (2C, Ar), 129.35 br.s (1C,
=CHN), 129.61 (1C), 129.93 (1C), 132.20 (1C). Found,
%: C 62.47; H 6.72; N 14.49. C10H12N2O2. Calculated,
%: C 62.49; H 6.29; N 14.57.
Thus a one-stage method was developed of the syn-
thesis of E-1-(alkoxy-NNO-azoxy)-2-arylethenes from
available bis(alkoxy-NNO-azoxy)methanes.
E-2-(2-fluorophenyl)-1-(methoxy-NNO-azoxy)
ethene (Vb) and 2-(2-fluorophenyl)-1,1-bis(methoxy-
NNO-azoxy)ethane (IIIb) a. To a solution of 1.02 g
(6.21 mmol) of compound I, 6.6 g (46 mmol) of
2-fluorobenzyl chloride, and 0.57 g (2 mmol) of TEBA-Cl
in 10 ml of CHCl3 was added at stirring 2.5 ml (42 mmol)
EXPERIMENTAL
1H and 13C NMR spectra were registered on a
spectrometer Avance III 500 Bruker BioSpin (500.20
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 49 No. 5 2013

ZYUZIN et al.
682
of NaOH solution. The reaction progress was monitored
by TLC, eluent benzene–ethyl acetate, 1 : 1 : Rf 0.17 (I),
0.49 (IIIb), 0.60 (Vb); CHCl3: Rf 0.04 (I), 0.07 (IIIb),
0.25 (Vb). After 12 h the reaction mixture was diluted
with water (200 ml), extracted with CH2Cl2 (3 × 20 ml),
the solvent was distilled off in a vacuum, 150 ml of
water was added, and it was distilled off in a vacuum
to remove with the azeotrope 2-fluorobenzyl chloride
and 2-fluorobenzyl alcohol. The residue was subjected
to flash-chromatography on silica gel Silpearl (65 ml),
eluent CHCl3→CHCl3–ethyl acetate, 5:1.
compound Vb. After 20 min the yellow reaction mixture
was diluted with water, extracted with CHCl3 (3 × 10 ml),
washed with brine. The extract was filtered through a bed
of silica gel 40–60 μm, the silica gel was washed with
CHCl3, and the solvent was distilled off in a vacuum.
The residue (148 mg) was recrystallized from a mixture
t-BuOMe–hexane. Yield 102 mg (52%), colorless needle
crystals, mp 80.2–81.2°С.
E-1-(Ethoxy-NNO-azoxy)-2-(2-fluorophenyl)-
-ethene (VIb). To a solution of 1.93 g (1 mmol) of
compound II, 1.8 ml (15 mmol) of 2-fluorobenzyl
chloride, and 0.23 g (1 mmol) of TEBA-Cl in 6 ml of
DMSO was added at stirring 1.5 ml (25 mmol) of NaOH
solution. The reaction progress was monitored by TLC
(eluent benzene–ethyl acetate, 3 : 1), Rf 0.15 (II), 0.50
(IVb), 0.67 (VIb). After 1.2 h the reaction mixture was
diluted with water, extracted with CH2Cl2, washed with
brine. The solvent was distilled off in a vacuum, 100 ml
of water was added, and it was distilled off in a vacuum
to remove with the azeotrope 2-fluorobenzyl chloride
and 2-fluorobenzyl alcohol. The residue was subjected
to flash-chromatography on silica gel Silpearl (60 ml),
eluent CHCl3. The fraction containing compound VIb
(0.62 g) was recrystallized from a mixture Et2O–hexane in
a freezer. Yield 0.32 g (48%), mp 25.5–26.5°С. 1H NMR
spectrum, δ, ppm: 1.459 t (3H, CH3CH2O, J 7.1 Hz),
4.471 q (2H, CH3CH2O, J 7.1 Hz), 7.132 d.d.d (1H, Ar,
J 11.1, 8.2, 1.1 Hz), 7.182 t.d (1H, Ar, J 7.6, 1.1 Hz),
7.335–7.381 symmetric m (1H, Ar), 7.467 t.d (1H, Ar,
J 7.6, 1.6 Hz), 7.661 d (1H, =CHN, J 13.8 Hz), 7.763 br.d
(1H, ArCH=, J 13.8 Hz). 13C NMR spectrum, δ, ppm:
14.56 s (CH3CH2O), 70.90 s (CH3CH2O), 116.09 d
(Ar, C3, 2JCF 21.8 Hz), 120.34 d (JCF 12.0 Hz), 123.44 s
(Δν1/2 1.6 Hz), 124.65 d (JCF 3.6 Hz), 130.76 d (JCF 3.1 Hz),
131.28 d (JCF 8.7, Δν1/2 1.6 Hz), 131.90 br.d (=CHN,
4JCF 11.6,Δν1/2 ~5 Hz), 161.20 d (Ar, C2, 1JCF –253.5 Hz).
Mass spectrum, m/z (Irel, %): 210 [M]+ (21), 181 [M – Et]+
(12), 152 (19), 151 [M – Et – NO]+ (79), 135 (20), 125
(24), 124 (25), 122 (57), 121 (56), 120 (71), 109 (45),
108 (14), 107 (13), 101 (100), 100 (12), 97 (18), 96 (22),
95 (18), 94 (19), 75 (55), 70 (12), 63 (12), 57 (12), 51
(26), 50 (22), 45 (25), 43 (18), 40 (33), 39 (12). Found,
%: C 57.43; H 6.58; N 15.01. C10H11FN2O2. Calculated,
%: C 57.14; H 5.27; N 13.33.
The fraction containing compound Vb (0.28 g) was
recrystallized from a mixture Et2O–benzene. Yield 0.15 g
1
(12%), mp 80.3–81.3°С. H NMR spectrum, δ, ppm:
4.189 s (3H, MeO), 7.131 d.d.d (1H, Ar, J 11.1, 8.2,
1.2 Hz), 7.182 t.d (1H, Ar, J 7.6, 1.2 Hz), 7.338–7.383
symmetric m (1H, Ar), 7.462 t.d (1H, Ar, J 7.6, 1.7 Hz),
7.649 d (1H, =CHN, J 13.9 Hz), 7.665 br.d (1H, ArCH=,
J 13.9 Hz). 13C NMR spectrum, δ, ppm: 61.91 s (CH3O,
Δν1/2 ~0.6 Hz), 116.28 d (Ar, C3, 2JCF 21.8 Hz), 120.27 d
(JCF 12.1 Hz), 123.71 s, 124.67 d (JCF 3.7 Hz), 130.76 d
(JCF 3.2 Hz), 131.38 d (JCF 8.8 Hz), 131.68 br.d (=CHN,
4JCF 11.8,Δν1/2 ~5 Hz), 161.23 d (Ar, C2, 1JCF –253.7 Hz).
Found, %: C 57.09; H 5.84; N 16.08. C9H9FN2O2.
Calculated, %: C 55.10; H 4.62; N 14.28.
The fraction containing compound IIIb (0.32 g)
was recrystallized from Et2O. Yield 0.13 g (8%), mp
1
112.9–113.6°С. H NMR spectrum, δ, ppm: 3.791 br.d
(2H, CH2CH, J 7.5 Hz), 4.079 s (6H, MeO), 6.177 t (1H,
CH2CH, J 7.5 Hz), 7.090 distorted t (2H, Ar, J 8.4 Hz),
7.246 distorted t.d (1H, Ar, J 7.5, 1.6 Hz), 7.290–
7.336 m (1H, Ar). 13C NMR spectrum, δ, ppm: 28.93
3
d (CH2, JCF 2.3 Hz), 62.19 s (CH3O, Δν1/2 ~0.6 Hz),
4
92.04 br.d (CN2, Δν1/2 ~5, JCF 1.7 Hz), 115.51 d (Ar,
C3, 2JCF 21.1 Hz), 119.19 d (Ar, JCF 14.9 Hz), 124.77 d
(Ar, JCF 3.7 Hz), 130.24 d (Ar, J 8.2 Hz), 132.03 d (Ar,
J 3.8 Hz), 161.19 d (Ar, C2, 1JCF –246.3 Hz). Found, %:
C 44.76; H 6.01; N 23.09. C10H13FN4O4. Calculated, %:
C 44.12; H 4.81; N 20.58.
Additional elution with a mixture CHCl3–ethyl
acetate, 2:1 provided 0.05 g (5%) of initial compound I,
mp 133°С (136°С [8]).
Compound (Vb). b. To a solution of 272 mg (1 mmol)
of compound IIIb and 23 mg (0.1 mmol) of TEBA-Cl in
2.5 ml DMSO was added at stirring 130 mg (1.5 mmol)
of NaOH solution. According to TLC data [eluent
benzene–ethyl acetate, 1:1, Rf 0.49 (IIIb), 0.61 (Vb)]
5 min later compound IIIb completely reacted forming
E-2-(2-Chlorophenyl)-1-(methoxy-NNO-azoxy)-
ethene (Vc). To a solution of 1.64 g (0.01 mol) of com-
pound I, 3.22 g (0.02 mol) of 2-chlorobenzyl chloride, and
0.23 g (0.001 mol) TEBA-Cl in 8 ml of DMSO at stirring
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SYNTHESIS OF E-1-(ALKOXY-NNO-AZOXY)-2-ARYLETHENES
683
130.60 (1C), 135.93 (1C, Ar, C4). Found, %: C 50.84;
H 4.46; N 13.04. C9H9ClN2O2. Calculated, %: C 50.84;
H 4.27; N 13.17.
while cooling on an ice bath was added 1.71 g (0.02 mol)
of NaOH solution was added. The reaction progress was
monitored by TLC (eluent benzene–ethyl acetate, 3 : 1),
Rf 0.08 (I), 0.38 (IIc), 0.54 (IIIc). After 2 h the reaction
mixture contained initial compound I. The reaction mix-
ture was diluted with water, extracted with CH2Cl2 (3 ×
10 ml), washed with brine (3 × 20 ml). The solvent was
distilled off in a vacuum. The residue was subjected to
flash-chromatography on silica gel Silpearl (50 ml), eluent
CH2Cl2. The fraction containing compound Vc (0.92 g)
was recrystallized from a mixture Et2O–pentane. Yield
E-2-(2,4-Dichlorophenyl)-1-(methoxy-NNO-
azoxy)ethene (Ve). To a solution of 1.64 g (0.01 mol) of
compound I, 3.22 g (0.0232 mol) of 2,4-dichlorobenzyl
chloride, and 0.23 g (0.001 mol) of TEBA-Cl in 11 ml of
DMSO at stirring while cooling with water (~20°С) was
added 0.92 g (0.011 mol) of NaOH solution.After 15 min
was added more 1.06 g (in total 1.98 g, 0.024 mol) of
NaOH solution. The reaction progress was monitored by
TLC (eluent benzene–ethyl acetate, 3 : 1), Rf 0.45 (IIIe).
After 1.5 h the reaction mixture was diluted with water,
extracted with CH2Cl2 (3 × 10 ml), washed with brine
(3 × 20 ml), and dried with CaCl2. The dark extract was
chromatographed on silica gel Silpearl (62 ml), eluent
CH2Cl2. The fraction containing compound Ve (0.83
g) was recrystallized from Et2O. Yield 0.52 g (21%),
mp 129.5–130.0°С. 1H NMR spectrum, δ, ppm: 4.189 s
(3H, MeO), 7.273 d.d.d (1H, Ar, J 8.4, 2.1, 0.5 Hz),
7.458 d (1H, Ar, J 2.1 Hz), 7.473 br.d (1H, Ar, J 8.4 Hz),
7.474 d (1H, =CHN, J 13.8 Hz), 8.014 br.d (1H, ArCH=,
1
0.62 g (29%), mp 60.1–60.8°С. H NMR spectrum, δ,
ppm: 4.184 s (3H, MeO), 7.265–7.332 m (2H, Ar), 7.435
distorted d.d (1H,Ar, J 7.8, 1.7 Hz), 7.484 d (1H, =CHN,
J 13.8 Hz), 7.532 distorted d.d (1H, Ar, J 7.6, 1.9 Hz),
8.085 d (1H, ArCH=, J 13.8 Hz). 13C NMR spectrum,
δ, ppm: 61.91 (CH3O, Δν1/2 1.4 Hz), 126.41, 127.15,
127.92, 130.38, 130.57, 130.87, 131.22 br.s (=CHN,
Δν1/2 5.5 Hz), 134.82 (Ar, C2). Mass spectrum, m/z (Irel,
%): 214 (23) [M (37Cl)]+, 212 (68) [M (35Cl)]+, 169 (31)
[M (37Cl) – Me – NO]+, 168 (12), 167 (70) [M (35Cl) –
Me – NO]+, 140 (12), 139 (40) [ArCH=CH (37Cl)]+, 138
(67), 137 (73) [ArCH=CH (35Cl)]+, 136 (82), 133 (25),
132 (100) [M – Me – NO – Cl]+, 125 (15), 118 (31), 102
(75) [ArCH=CH – Cl]+, 101 (83) [M – Ar]+, 89 (14),
77 (13), 76 (24), 75 (71) [M – ArCH=CH]+, 74 (16), 63
(15). Found, %: C 51.25; H 4.38; N 13.08. C9H9ClN2O2.
Calculated, %: C 50.84; H 4.27; N 13.17.
13
J 13.8 Hz). C NMR spectrum, δ, ppm: 61.99 (CH3O,
Δν1/2 3.7 Hz), 125.34, 127.62, 128.61, 129.21, 130.23,
131.51 br.s (=CHN, Δν1/2 9.3 Hz), 135.44 (Ar), 136.16
(Ar). Found, %: C 43.95; H 3.53; N 11.20. C9H8Cl2N2O2.
Calculated, %: C 43.75; H 3.26; N 11.34.
E-2-(4-Bromophenyl)-1-(methoxy-NNO-azoxy)-
ethene (Vf) and 1,3-bis(4-bromophenyl)-2,2-
bis(methoxy-NNO-azoxy)propane (VII). To a solution
of 1.64 g (0.01 mol) of compound I, 2.55 g (0.0102 mol)
of 4-bromobenzyl bromide, and 0.23 g (0.001 mol) of
TEBA-Cl in 8 ml of DMSO at stirring while cooling
on an ice bath was added 1.05 g (0.012 mol) of NaOH
solution. The reaction progress was monitored by TLC
(eluent benzene–ethyl acetate, 3 : 1), Rf 0.28 (IIIf), 0.41
(Vf), 0.51 (VII). After 1 h was added more 1.15 g (in
total 2.2 g, 0.026 mol) of NaOH solution and 5 ml of
DMSO. The reaction mixture turned dark, gas libera-
tion was observed. After 1.5 h the reaction mixture was
diluted with water, extracted with CH2Cl2 (3 × 20 ml),
washed with brine (2 × 50 ml). The extract was chro-
matographed on silica gel 40–100 μm (118 ml), eluent
CH2Cl2–hexane, CH2Cl2–Et2O, compound VII was
eluted after compound Vf.
E-2-(4-Chlorophenyl)-1-(methoxy-NNO-azoxy)-
ethene (Vd). To a solution of 1.64 g (0.01 mol) of
compound I, 3.22 g (0.02 mol) of 4-chlorobenzyl chloride,
and 0.23 g (0.001 mol) of TEBA-Cl in 8 ml of DMSO
at stirring while cooling on an ice bath was added 1.84 g
(0.022 mol) of NaOH solution. The reaction progress was
monitored by TLC (eluent benzene–ethyl acetate, 3 : 1),
Rf 0.08 (I), 0.26 (IId), 0.43 (IIId).After 0.5 h the reaction
mixture was diluted with water, extracted with CH2Cl2 (3
× 10 ml), washed with brine (3 × 20 ml). The solvent was
distilled off in a vacuum. The residue was subjected to
flash-chromatography on silica gel Silpearl (50 ml), eluent
CH2Cl2. The fraction containing compound Vd (1.35 g)
was recrystallized from Et2O. Yield 1.01 g (48%), mp
80–81°С. 1H NMR spectrum, δ, ppm: 4.177 s (3H, MeO),
7.362 d.t (2H, Ar, J 8.6, 2.1 Hz), 7.415 d.t (2H, Ar, J 8.6,
2.1 Hz), 7.438 d (1H, =CHN, J 13.8 Hz), 7.687 br.d (1H,
ArCH=, J 13.8 Hz). 13C NMR spectrum, δ, ppm: 61.90
(1C, CH3O, Δν1/2 1.3 Hz), 128.62 (1C), 129.08 (2C, Ar),
129.32 (2C, Ar), 129.52 br.s (1C, =CHN, Δν1/2 4.6 Hz),
The fraction containing compound Vf (1.45 g) was
recrystallized from Et2O. Yield 1.03 g (40%), mp 128.3–
129.0°С. 1H NMR spectrum, δ, ppm: 4.170 s (3H, MeO),
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 49 No. 5 2013

ZYUZIN et al.
684
Reaction of 4-nitrobenzyl chloride with
bis(methoxy-NNO-azoxy)methane. To a solution of
1.64 g (0.01 mol) of compound I, 3.43 g (0.02 mol) of
4-nitrobenzyl chloride, and 0.23 g (0.001 mol) of TEBA-
Cl in 10 ml of DMSO at stirring while cooling on an ice
bath was added 2.05 g (0.0244 mol) of NaOH solution.
The reaction mixture suffered tarring, gas evolution was
observed. After 1 h the reaction mixture was diluted
with water and CH2Cl2 and was acidified with HCl. The
separated yellow precipitate was filtered off, washed with
water and CH2Cl2 and was recrystallized from DMF.
A mixture of compounds VIII, IX was obtained. Yield
7.346 d.t (2H, Ar, J 8.3, 2.1 Hz), 7.453 d (1H, =CHN,
J 13.8 Hz), 7.519 d.t (2H, Ar, J 8.4, 2.1 Hz), 7.670 br.d
(1H, ArCH=, J 13.8 Hz). 13C NMR spectrum, δ, ppm:
61.91 (1C, CH3O, Δν1/2 ~0.6 Hz), 124.21 (1C, Ar, C4),
128.69 (1C), 129.29 (2C, Ar), 129.56 br.s (1C, =CHN,
Δν1/2 ~3.8 Hz), 131.01 (1C), 132.27 (2C, Ar). Found, %:
C 41.88; H 3.53; N 10.85. C9H9BrN2O2. Calculated, %:
C 42.05; H 3.53; N 10.90.
The fraction containing compound VII (0.52 g) was
recrystallized from methanol. Yield 0.26 g (5.2%, 10.3%
calculated on 4-bromobenzyl bromide), mp 190°С (de-
1
comp.), at fast heating mp 204°С (decomp.). H NMR
1
0.42 g (15%), mp 280°С. H NMR spectrum, δ, ppm:
7.701 s (~2H, Ar), 7.947 d (4H, Ar, J 9.0 Hz), 8.288 d
(4H, Ar, J 8.9 Hz). Found, %: C 61.14; H 3.67; N 10.15.
spectrum, δ, ppm (3% solution in CDCl3): 3.563 s (4H,
CH2C), 4.064 s (6H, MeO), 7.043 distorted d (4H, Ar,
J 8.1 Hz), 7.482 distorted d (4H, Ar, J 8.4 Hz). 13C NMR
spectrum, δ, ppm (3% solution in CDCl3): 36.95 (2C,
CH2, Δν1/2 ~1.3 Hz), 62.32 (2C, CH3O, Δν1/2 ~0.5 Hz),
104.03 (1C, CN2,Δν1/2 ~1.3 Hz), 122.49 (2C,Ar, C4,Δν1/2
~0.6 Hz), 131.01 (2C, Ar), 131.93 (4C, Ar), 131.94 (4C,
Ar). Found, %: C 40.49; H 3.82; N 11.01. C17H18Br2N4O4.
Calculated, %: C 40.66; H 3.61; N 11.16.
4,4'-Dicarboxyazobenzene (VIII). C14H10N2O4.
Calculated, %: С 62.22; H 3.73; N 10.37.
4,4'-Dicarboxyazoxybenzene (IX). C14H10N2O5.
Calculated, %: C 58.74; H 3.52; N 9.79.
ACKNOWLEDGMENTS
E-1-(Methoxy-NNO-azoxy)-2-(1-naphthyl)ethene
(Vg). To a solution of 1.64 g (0.01 mol) of compound I,
4.00 g (0.0226 mol) of 1-chloromethylnaphthalene, and
0.23 g (0.001 mol) of TEBA-Cl in 10 ml of DMSO at
stirring while cooling on an ice bath was added 1.90 g
(0.023 mol) of NaOH solution. The reaction progress
was monitored by TLC (benzene–ethyl acetate, 3 : 1), Rf
0.10 (I), 0.46 (Vg).After 40 min the reaction mixture was
diluted with water, extracted with CH2Cl2 (2 × 30 ml),
washed with brine (3 × 20 ml), and dried with CaCl2.
The light orange extract was chromatographed on silica
gel Silpearl (50 ml), eluent CH2Cl2. The fraction con-
taining compound Vg (2.16 g) was recrystallized from
Et2O. Yield 1.265 g (55%), mp 104.0–104.8°С. 1H NMR
spectrum, δ, ppm: 4.197 s (3H, MeO), 7.463 br.t (1H, Ar,
J 7.6 Hz), 7.488 d (1H, =CHN, J 13.5 Hz), 7.516–7.589
m (2H, Ar), 7.646 br.d (1H, Ar, J 7.1 Hz), 7.877 br.t (2H,
Ar, J 8.2 Hz), 8.147 br.d (1H, Ar, J 8.5 Hz), 8.517 br.d
(1H, ArCH=, J 13.5 Hz). 13C NMR spectrum, δ, ppm:
61.88 (CH3O, Δν1/2 ~1.4 Hz), 123.58, 124.88, 125.37,
126.41, 127.00, 127.28, 128.71, 129.38, 130.39, 130.88
br.s (=CHN, Δν1/2 ~4.8 Hz), 131.45, 133.67. Found, %:
C 66.75; H 6.01; N 12.82. C12H12N2O2. Calculated, %:
C 66.65; H 5.59; N 12.95.
The author is grateful to PhD A.V. Chernyak for
registering the NMR spectra.
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