Synthesis of methoxy-NNO-azoxyethene

Article abstract of DOI:10.1023/a:1024851816572

The first representative of the alkoxy-NNO-azoxy olefin series, viz., methoxy-NNO-azoxyethene, was synthesized by the pyrolysis of 1,1-bis(methoxy-NNO-azoxy)ethane.

Full text of DOI:10.1023/a:1024851816572

Russian Chemical Bulletin, International Edition, Vol. 52, No. 6, pp. 1431—1433, June, 2003
1431
Synthesis of methoxyꢀNNOꢀazoxyethene
ꢀ
I. N. Zyuzin, D. B. Lempert, and G. N. Nechiporenko
Institute of Problems of Chemical Physics, Russian Federation,
142432 Chernogolovka, Moscow Region, Russian Federation.
Fax: +7 (096) 515 3588. Eꢀmail: zyuzin@icp.ac.ru
The first representative of the alkoxyꢀNNOꢀazoxy olefin series, viz., methoxyꢀNNOꢀ
azoxyethene, was synthesized by the pyrolysis of 1,1ꢀbis(methoxyꢀNNOꢀazoxy)ethane.
Key words: alkoxyꢀNNOꢀazoxy olefins, methoxyꢀNNOꢀazoxyethene, 1,1ꢀbis(methoxyꢀ
NNOꢀazoxy)ethane, pyrolysis, UV spectra.
Five alkoxyꢀNNOꢀazoxy olefins with the C=C double
bond at the Nꢀoxide nitrogen atom are known, and four of
them are styrene derivatives.1,2 Only one such azoxy olefin
containing no aromatic substituent, viz., 1ꢀ(methoxyꢀ
NNOꢀazoxy)propꢀ1ꢀene (1), was synthesized3 by the
isomerization of 3ꢀ(methoxyꢀNNOꢀazoxy)propꢀ1ꢀene (2)
(Scheme 1).
We found that the thermolysis of compound 4 affords,
indeed, azoxy olefin 3. As can be seen from the data in
Table 1, the chromatographic yield of compound 3 in
the 220—272 °C temperature interval changes slightly
(71—75%). At lower temperatures, the yield decreases
due to a low conversion at an appropriate duration of the
process. However, the yield based on the decomposed
starting compound 4 remains high. At temperatures higher
than 272 °C, the yield decreases due to the destruction of
product 3. The chromatographic yield is highest at 260 °C
and a duration of the reaction of 20 min (75%). The
preparative synthesis of compound 3 in 53% yield was
carried out under these conditions.
Scheme 1
Compound 3 is a colorless liquid with a strong smell.
It is indefinitely soluble in water EtOH, Me2CO, and
Et2O, is immiscible with hexane, and discolors a solution
of Br2 in CHCl3.
The substantial shift of the band of the π—π*ꢀtransiꢀ
tion in the UV spectrum of compound 3 (λmax = 250 nm)
toward the longꢀwave region compared to those of
The simplest azoxy olefin (methoxyꢀNNOꢀazoxyꢀ
ethene (3)) cannot be synthesized by this method. Howꢀ
ever, it is ethene 3 which is the most interesting as a
monomer for the preparation of powerꢀrich polymeric
compositions.4
The purpose of this work was to study the possibility of
synthesis of compound 3 using the vacuum pyrolysis of
1,1ꢀbis(methoxyꢀNNOꢀazoxy)ethane (4)5 (Scheme 2).
Table 1. Yields of compound 3 under different pyrolysis conꢀ
ditions
Т/°С
Duration
of reaction
Degree
of conversion
Yield*
Scheme 2
%
168
190
220
230
240
250
260
272
285
300
6.5 h
10 h
2.3 h
1.3 h
1.0 h
30 min
20 min
13 min
8 min
5 min
11
84
99
100
100
100
100
100
100
100
8 (70)
53 (70)
71 (71)
74 (74)
74 (74)
74 (74)
75 (75)
72 (72)
65 (65)
59 (59)
The formation of βꢀ(methoxyꢀNNOꢀazoxy)styrene by
the pyrolysis of 1,1ꢀbis(methoxyꢀNNOꢀazoxy)ꢀ2ꢀphenylꢀ
ethane2 and a ∼100% yield of isobutylene in the thermal
decomposition of 2ꢀmethylꢀ2ꢀ(methoxyꢀNNOꢀazoxy)proꢀ
pane in the gas phase6 indicated that this reaction is posꢀ
sible in principle.
* The yield of compound 3 based on reacted compound 4 is
presented in parentheses.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1354—1356, June, 2003.
1066ꢀ5285/03/5206ꢀ1431 $25.00 © 2003 Plenum Publishing Corporation

1432
Russ.Chem.Bull., Int.Ed., Vol. 52, No. 6, June, 2003
Zyuzin et al.
methoxyꢀNNOꢀazoxymethane (5) (λmax = 234 nm)7 and
allyloxyꢀNNOꢀazoxymethane (6) (λmax = 234 nm)8 indiꢀ
cates the π—πꢀconjugation between the sixꢀelectron
πꢀsystem of the N2O2 group9 and the С=С bond.
and 7.12 ppm, whereas those in compound 3 in CDCl3
and in the absence of a solvent are equal to 5.37, 6.25,
6.93 and 5.59, 6.32, 7.31 ppm, respectively. This assignꢀ
ment of the vinylic protons of compound 3 agrees with the
spinꢀspin coupling constants (see Experimental). The spinꢀ
spin coupling constant of the atoms in the transꢀposition
(15 Hz), as for nitroethene (15.0 Hz),12 is much lower
than that for unsubstituted ethene (19 Hz) due to a deꢀ
crease in the electron density around the vinylic protons
under the effect of the electronꢀacceptor group.12
In the 13C NMR spectrum of compound 3, the signal
of the MeO group at δ 61.5 exists in the region characterꢀ
istic of several other methoxyꢀNNOꢀazoxy compounds
(δ 60—63 in CDCl3).13—15 The 13C NMR signals of the
vinyl group were assigned by the comparison with the
spectroscopic characteristics of nitro olefins.12
The hydroxydiazeneoxide group can be presented by a
set of four resonance forms9 (Scheme 3). In the resoꢀ
nance form 11, the O...O bond designates the πꢀinteracꢀ
tion without a σꢀbond. Probably, valent forms 8 and 9
contribute mainly to the conjugation with the С=С bond
in molecule 3.
The 14N NMR spectrum of compound 3 exhibits a
relatively narrow (∆ν1/2 ∼80 Hz) signal at δ –66.8 characꢀ
teristic of the Nꢀoxide nitrogen atom,13 which was deꢀ
scribed for several other alkoxyꢀNNOꢀazoxy compounds
(δ = –66—–71, ∆ν1/2 = 80—220 Hz).13,14
In the mass spectrum of compound 3, the peak of the
molecular ion is most intense, and fragmentation agrees
with the published data.1,16 In particular, the most inꢀ
tense peaks of ions in the mass spectrum of βꢀ(ethoxyꢀ
NNOꢀazoxy)styrene1 [M]+, [M – Et]+, [M – EtNO]+,
and [EtNO]+ are similar to the most intense peaks in the
spectrum of compound 3.
Scheme 3
Thus, the first member of the alkoxyꢀNNOꢀazoxy oleꢀ
fin series, viz., methoxyꢀNNOꢀazoxyethene (3), was
synthesized by the pyrolysis of 1,1ꢀbis(methoxyꢀNNOꢀ
azoxy)ethane (4) in melt.
Experimental
Almost the same great shift of the band of the
π—π*ꢀtransition in the UV spectrum was detected for the
isomer of compound 3: vinyloxyꢀNNOꢀazoxymethane (7)
(λmax = 248 nm).10 However, resonance forms 10 and 11
are involved in conjugation with the C=C bond in this case.
The IR spectrum of compound 3 exhibits intense abꢀ
sorption bands at 1290, 1390, and 1480 cm–1 characterisꢀ
tic of the N2O2 group.1,3,7—10 The band of stretching viꢀ
brations of the C=C bond with a medium intensity lies11
The IR spectrum was recorded with a Specord IRꢀ75
spectrometer (in thin film). The UV spectrum was recorded
with an Specord Mꢀ40 spectrometer (solutions in H2O).
1H (200.13 MHz), 13C (50.32 MHz), and 14N (21.69 MHz)
NMR spectra were obtained on a Bruker ACꢀ200 spectrometer
(in CDCl3). Chemical shifts for 1H and 13C were measured
relatively to the solvent signals (7.25 and 77.0 MHz), and those
for 14N were measured relatively to the external standard
1
(MeNO2). The H NMR spectrum without a solvent was reꢀ
at 1655 cm–1
.
corded with an NMR spectrometer (294 MHz) designed and
manufactured at the Institute of Problems of Chemical Physics
of the Russian Academy of Sciences (IPCP RAS) using Me4Si
as the internal standard (signals of protons were assigned by
analogy, see above). The mass spectrum was obtained with an
MXꢀ1320 spectrometer (EI, 70 eV).
The yield of compound 3 was studied in sealed ∼180ꢀmL
glass vessels with a falcate membrane, using a weighed sample of
compound 4 of ∼150 mg. The reaction course was monitored by
a change in the pressure of gaseous products.6 The temperature
in these experiments and during the synthesis of compound 3
was maintained with an accuracy of 0.2 K using an air thermoꢀ
stat designed and manufactured at the IPCP RAS and measured
In the 1H NMR spectrum of compound 3, the singlet
of the methoxy group (δ 4.15) demonstrates a slight
downfield shift compared to methoxyꢀNNOꢀazoxyalkanes
1
(δ 3.89—3.95), whose H NMR spectra were measured
under the same conditions.7 The methoxyꢀNNOꢀazoxy
group in its electron influence resembles much its isoelecꢀ
tronic nitro group. Therefore, these groups should deshield
the ethenic protons in a similar manner, despite different
conditions of spectra recording. The chemical shifts of the
transꢀ, cisꢀ, and gemꢀprotons of the vinyl group in nitroꢀ
ethene (a 10% solution in CCl4) are equal12 to 5.87, 6.55,

Synthesis of methoxyꢀNNOꢀazoxyethene
Russ.Chem.Bull., Int.Ed., Vol. 52, No. 6, June, 2003
1433
with a calibrated chromel—copel thermocouple. The yield of
compound 3 was determined using GLC with an LKhMꢀ8MD
chromatograph (column packed with 15% Carbowaxꢀ20М on
m/z (Irel (%)): 102 [M]+ (100), 87 [M – Me]+ (85), 58 (14), 57
[M – MeNO]+ (70), 46 (6), 45 [MeNO]+ (16), 43 (11), 42 (8),
41 (6), 40 (4), 32 (6), 31 (16), 30 (38), 29 (19), 28 (47), 27 (59).
Chromaton NꢀAW DMCS, N2 as the carrier gas, 30 mL min–1
,
The authors thank G. V. Lagodzinskaya and D. E.
Dmitriev for recording NMR spectra.
temperature of the column 150 °C, temperature of the evaporaꢀ
tor 200 °C), τ = 6.6 min, PhCN as the internal standard,
sp
τ
sp = 5.25 min.
References
1,1ꢀBis(methoxyꢀNNOꢀazoxy)ethane (4) was synthesized acꢀ
cording to a modified procedure.5 Nitrogen oxide17 was passed
through a solution of NaOH (98%, 245 g, 6 mol) and ethyl
methyl ketone (400 mL, 322 g, 4.47 mol, 2.23 equiv.) in MeOH
(2.5 L) with vigorous stirring and cooling with such a rate that
NO was completely absorbed, maintaining the temperature at
20—25 °C. A precipitate began to form after 20 min, and after
2 h the absorption of NO was sharply slowed down. The reaction
mixture was additionally stirred in an NO atmosphere for 3 h at
∼20 °C and neutralized by phenolphthalein with AcOH (5 mL).
The precipitate was filtered off, washed with MeOH (1 L) and
Et2O (1 L), and dried in air at the relative humidity not higher
than 60% (the product smeared at the humidity higher
than 70%). Thus obtained 1,1ꢀbis(nitrosohydroxylamino)ethane
disodium salt (490 g) was suspended without purification in DMF
(1 L), and Na2CO3 (53 g, 0.5 mol) was added. Then dimethyl
sulfate (560 mL, 5.8 mol) was gradually added with stirring and
cooling for 3.5 h, maintaining the temperature at 20—25 °C.
Plentiful gas evolution was observed, and the reaction mixture
darkened and homogenized, except for a minor precipitate of
Na2CO3. The mixture was additionally stirred for 0.5 h at 20 °C
and for 0.5 h at 50 °C, and the solvent was distilled off on a
rotary evaporator at 20—95 °C (8 Torr). In this distillation, the
target product was not distilled off (≤ 0.1%). Attention! The byꢀ
product, cancerogenic Nꢀnitrosodimethylamine, was distilled off
along with DMF. The residue was dissolved in water (1 L) and
extracted with CHCl3 (400 mL) for 15 h in a liquidꢀliquid exꢀ
tractor for the heavy organic phase. The extract (∼0.5 L) was
passed through a column packed with silica gel (100—160 µm,
100 g), washed with CHCl3 (250 mL), and evaporated in vacuo.
The residue was recrystallized from EtOH (200 mL). The yield
of the product was 118 g (16% based on ethyl methyl ketone),
m.p. 72—74 °C (cf. Ref. 5: m.p. 75—75.5 °C). After recrystalliꢀ
zation from an H2O—MeOH mixture, the product (92 g) was
obtained with m.p. 75—75.5 °C.
1. I. N. Zyuzin, Izv. Akad. Nauk, Ser. Khim., 1998, 1263 [Russ.
Chem. Bull., 1998, 47, 1231 (Engl. Transl.)].
2. R. B. Woodrward and C. Wintner, Tetrahedron Lett., 1969,
32, 2689.
3. O. A. Luk´yanov and N. I. Shlykova, Izv. Akad. Nauk, Ser.
khim., 1998, 2262 [Russ. Chem. Bull., 1998, 47, 2193 (Engl.
Transl.)].
4. I. N. Zyuzin, A. A. Baturina, V. P. Grachev, D. B. Lempert,
and G. N. Nechiporenko, Tez. dokl. Vseros. nauchn. konf.
"Energeticheskie kondensirovannye sistemy" (Chernogolovka,
October 28—31, 2002), Chernogolovka, 2002, 38 (in Russian).
5. L. O. Atovmyan, N. I. Golovina, and I. N. Zyuzin, Izv.
Akad. Nauk SSSR, Ser. Khim., 1987, 1309 [Bull. Acad. Sci.
USSR, Div. Chem. Sci., 1987, 36, 1205 (Engl. Transl.)].
6. I. N. Zyuzin, D. B. Lempert, and G. N. Nechiporenko, Izv.
Akad. Nauk SSSR, Ser. Khim., 1988, 1506 [Bull. Acad. Sci.
USSR, Div. Chem. Sci., 1988, 37, 1329 (Engl. Transl.)].
7. I. N. Zyuzin and D. B. Lempert, Izv. Akad. Nauk SSSR, Ser.
Khim., 1985, 831 [Bull. Acad. Sci. USSR, Div. Chem. Sci.,
1985, 34, 753 (Engl. Transl.)].
8. I. N. Zyuzin, Izv. Akad. Nauk SSSR, Ser. Khim., 1985, 2626
[Bull. Acad. Sci. USSR, Div. Chem. Sci., 1985, 34, 2433 (Engl.
Transl.)].
9. I. N. Zyuzin, G. N. Nechiporenko, N. I. Golovina, R. F.
Trofimova, and M. V. Loginova, Izv. Akad. Nauk, Ser.
Khim., 1997, 1486 [Russ. Chem. Bull., 1997, 46, 1421 (Engl.
Transl.)].
10. I. N. Zyuzin and G. N. Nechiporenko, Izv. Akad. Nauk,
Ser. Khim., 1998, 2390 [Russ. Chem. Bull., 1998, 47, 2317
(Engl. Transl.)].
11. L. J. Bellamy, The InfraꢀRed Spectra of Complex Molecules,
Methuen, London, 1954.
12. V. V. Perekalin, A. S. Sopova, and E. S. Lipina, Nepredel´nye
nitrosoedineniya [Unsaturated Nitro Compounds], Khimiya,
Leningrad, 1982, pp. 337; 363 (in Russian).
13. O. A. Luk´yanov, G. A. Smirnov, and V. V. Sevost´yanova,
Izv. Akad. Nauk, Ser. Khim., 1995, 1534 [Russ. Chem. Bull.,
1995, 44, 1474 (Engl. Transl.)].
MethoxyꢀNNOꢀazoxyethene (3). A 4ꢀL glass vessel containꢀ
ing compound 4 (7 g, 68.5 mmol, the maximum amount for
which the pressure of the pyrolysis products at 260 °C does not
exceed 1.5 atm) was evacuated with an oil pump (∼0.1 Torr),
sealed off and heated at 260 °C for 20 min, cooled, and opened.
The condensate was washed off with CHCl3 (30 mL). The solꢀ
vent was distilled off from the combined washings of five analoꢀ
gous experiments, and the residue was doubly distilled in vacuo.
The yield of the product was 10.6 g (53%), b.p. 66—68 °C
(8 Torr), nD20 1.4898, d420 1.111. UV, λmax/nm (ε): 250 (11170).
IR, ν/cm–1: 665, 745, 960, 1020, 1065, 1080, 1210, 1290 (N2O2),
1390 (N2O2), 1480 (N2O2), 1655 (C=C), 2845, 2960, 3000,
14. O. A. Luk´yanov, G. A. Smirnov, and S. V. Nikitin, Izv.
Akad. Nauk, Ser. Khim., 1998, 1996 [Russ. Chem. Bull., 1998,
47, 1940 (Engl. Transl.)].
15. Yu. A. Red´kin, G. A. Marchenko, L. N. Punegova, G. S.
Stepanov, and I. V. Tselinskii, Zh. Org. Khim., 1988, 24, 495
[J. Org. Chem. USSR, 1988, 24 (Engl. Transl.)].
16. I. G. Zenkevich, V. N. Yandovskii, Yu. P. Artsibasheva, and
V. S. Tselinskii, Zh. Org. Khim., 1987, 23, 3 [J. Org. Chem.
USSR, 1987, 23 (Engl. Transl.)].
1
3115, 3140. H NMR (without solvent, δ: 4.15 (s, 3 H, Me);
5.59 (d, 1 H, Hb, Ja,b = 7.5 Hz); 6.32 (d, 1 H, Hc, Ja,c = 15 Hz);
7.31 (dd, 1 H, Ha, Ja,b = 7.5 Hz, Ja,c = 15 Hz). 1H NMR
(CDCl3), δ: 4.02 (s, 3 H, Me); 5.37 (d, 1 H, Hb, Ja,b = 8 Hz);
6.25 (d, 1 H, Hc, Ja,c = 15 Hz); 6.93 (dd, 1 H, Ha, Ja,b = 8 Hz,
Ja,c = 15 Hz). 13C NMR, δ: 61.5 (CH3O); 113.6 (=CHN);
136.4 (CH2=). 14N NMR, δ, (∆ν1/2/Hz)): –66.8 (∼80). MS,
17. Yu. V. Karyakin and I. I. Angelov, Chistye khimicheskie
veshchestva [Pure Chemical Substances], Khimiya, Moscow,
1974, p. 24 (in Russian).
Received July 10, 2002;
in revised form March 13, 2003