Electrochemical synthesis of geminal azidonitro compounds

Article abstract of DOI:10.1007/s11172-005-0154-2

An electrochemical method for the synthesis of geminal azidonitro compounds was developed. The method involves electrooxidative coupling of azide anions with salts of nitro compounds and affords geminal azidonitroalkanes, azidonitrocycloalkanes, and diazi

Full text of DOI:10.1007/s11172-005-0154-2

2558
Russian Chemical Bulletin, International Edition, Vol. 53, No. 11, pp. 2558—2563, November, 2004
Electrochemical synthesis of geminal azidonitro compounds
ꢀ
Yu. N. Ogibin, A. I. Ilovaisky, V. M. Merkulova, and G. I. Nikishin
N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences,
4
7 Leninsky prosp., 119991 Moscow, Russian Federation.
Fax: +7 (095) 135 5328. Eꢀmail: ogibin@ioc.ac.ru
An electrochemical method for the synthesis of geminal azidonitro compounds was develꢀ
oped. The method involves electrooxidative coupling of azide anions with salts of nitro comꢀ
pounds and affords geminal azidonitroalkanes, azidonitrocycloalkanes, and diazidodinitroꢀ
cycloalkanes in 45—92% yields.
Key words: salts of nitro compounds, azide anions, electrooxidative coupling, monoꢀ and
di(αꢀazido)nitro compounds, electrosynthesis.
Geminal azidonitroalkanes, azidonitrocycloalkanes,
Scheme 1
and diazidodinitrocycloalkanes are of considerable interꢀ
est as compounds with a high energy capacity and promꢀ
ising synthons for construction of various polynitroꢀ
geneous structures.1 However, only a few compounds of
these types have been obtained to date: 1ꢀazidoꢀ1ꢀ
,2
2
3,4
nitroethane, ꢀbutane, and ꢀcyclohexane, 2ꢀazidoꢀ2ꢀ
nitropropane,3 1,4ꢀdiazidoꢀ1,4ꢀdinitrocyclohexane,
,5ꢀdiazidoꢀ2,5ꢀdinitronorbornane, and benzyl 6ꢀazidoꢀ
ꢀnitropenicillanate. The best results were attained in
,4
1
2
6
5
oxidative coupling of azide anions with salts of nitro comꢀ
1
,2,4
pounds with K Fe(CN) and (NH ) S O as oxidants.
3
6
4 2
2
8
A significant drawback of these methods is that multiple
molar excess of the oxidant and azide anions should be
used, which leads to the formation of large amounts of
toxic wastes difficult to handle. Until now, the electrolyꢀ
sis of azide anions in the presence of salts of nitro comꢀ
pounds was reported only as a route to 1ꢀazidoꢀ1ꢀnitroꢀ
alkanes, 2ꢀazidoꢀ2ꢀnitropropane, and 1ꢀazidoꢀ1ꢀnitroꢀ
6
,7
cyclohexane,
without specifying the electrosynthesis
conditions or the yields of the products (except for
1
ꢀazidoꢀ1ꢀnitrocyclohexane (89%)).
In the present study, electrooxidative coupling of azide
anions with Na salts of primary and secondary nitroalkanes
1a—d), 5ꢀnitroheptanꢀ2ꢀone (1e), methyl 4ꢀnitrohexaꢀ
noate (1f), nitrocycloalkanes (1g,h), 2ꢀnitronorbornane
1i), 1,4ꢀdinitrocyclohexane (2), and 2,5ꢀdinitronorborꢀ
(
(
nane (3) was successfully carried out to produce geminal
azidonitroalkanes 4a—f, azidonitrocycloalkanes 4g—i, and
diazidodinitrocycloalkanes 5 and 6 (Scheme 1).
R1
R2
R +R2
1
a
b
с
d
e
f
Me
Et
H
H
H
Me
Et
Et
g
h
i
(CH )
(CH2)6
2ꢀNorbornyl
2 5
Experiments were carried out in a twoꢀphase methylꢀ
ene chloride—water (or aqueous NaHCO and Na HPO )
n
С Н
5
11
3
2
4
Me
system (2 : 1, v/v) in undivided and divided cells with
.1 M aqueous NaOH and H SO as catholytes. In all
MeCOCH2CH2
MeO CCH CH
2
0
2
2
2
4
experiments, platinum served as an anode and stainless
steel as a cathode. The quantity of electricity passed was
varied from 2 to 12 F mol at an anodic current density
Reagents and conditions: CH Cl —H O, NaN (5 equiv.), diꢀ
2
2
2
3
vided or undivided cell with a platinum anode and a stainless
–
1
–1
steel cathode, 2—12 F mol , 8—10 °C.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2452—2457, November, 2004.
066ꢀ5285/04/5311ꢀ2558 © 2004 Springer Science+Business Media, Inc.
1

Synthesis of geminal azidonitro compounds
Russ.Chem.Bull., Int.Ed., Vol. 53, No. 11, November, 2004 2559
of 50—100 mA cm–2. Electrolysis was performed at
twoꢀphase CH Cl —water (or aqueous NaHCO ) system,
2
2
3
8
—10 °C; fivefold (with respect to salts of mononitro
while electrolysis in CH Cl —aqueous Na HPO gave
2 2 2 4
compounds) and tenfold molar excesses (with respect to
salts of dinitro compounds) of sodium azide were used.
The selected results obtained are given in Table 1.
compound 4a in only 4% yield. The satisfactory yield
(44—67%) of nitroazide 4a was attained only by electroꢀ
oxidative coupling of NaN with a salt of nitroethane in a
3
The electrolysis conditions significantly affect the
azidation of salts of primary nitroalkanes. For instance,
geminal azidonitroethane (4a) was not detected among
the products obtained by electrolysis of a mixture of
nitroethane salt—sodium azide in an undivided cell with a
divided cell with a twoꢀphase CH Cl —water (anolyte)
2
2
system (0.1 M H SO as a catholyte). In this case, the
2
4
quantity of electricity passed Q = 2 to 3 F/mol of the salt
ensured a 79—94% conversion of the latter (see Table 1,
entries 4, 5). Under the same conditions, 1ꢀazidoꢀ1ꢀ
Table 1. Electrooxidative coupling of NaN with salts of nitro compounds 1a—g, 2, and 3a
3
Entry
Anion of the salt
Electrolyzer
System
Q
Degree of
conversion (%)
Product
(yield (%) )
F mol–
1
b
/
1
2
3
4
5
6
7
8
9
MeCH=NO – (1a)
undivided
undivided
undivided
divided
divided
divided
divided
divided
divided
undivided
CH Cl —H O
2
2
2
2
3
2
3
4
6
4
78
86
97
79
94
75
95
72
98
4a (0)
4a (0)
4a (4)
4a (67)
4a (44)
4b (50)
4b (45)
4c (70)
4c (67)
2
2
2
2
«
«
«
«
CH Cl ꢀaq.NaHCO
3
2
2
CH Cl ꢀaq.Na HPO
2
2
2
4
CH Cl —H O
2
2
2
CH Cl —H O
2
2
2
EtCH=NO2– (1b)
CH Cl —H O
2
2
2
«
CH Cl —H O
2
2
2
–
nꢀC H CH=NO (1c)
CH Cl —H O
5
11
2
2
2
2
«
CH Cl —H O
2
2
2
–
c
10
Me C=NO2 (1d)
CH Cl —H O
100
4d (45)
2
2
2
2
1
1
(1e)
undivided
CH Cl —H O
4
100
4e (78)
2
2
2
1
1
2
3
(1f)
undivided
undivided
MeOH
3
4
95
83
4f (51)d
4g (92)
(1g)
CH Cl —H O
2 2 2
1
1
4
5
«
«
undivided
divided
CH Cl —H O
6
4
100
100
4g (84)
4g (84)
2
2
2
CH Cl —H O
2
2
2
1
1
6
7
(1h)
(1i)
undivided
undivided
CH Cl —H O
4
5
86
4h (90)
4h (88)
2
2
2
«
CH Cl —H O
100
2
2
2
1
1
8
9
undivided
undivided
CH Cl —H O
6
8
100
100
4i (76)
5 (75)
2
2
2
(2)
CH Cl —H O
2 2 2
2
0
(3)
undivided
CH Cl —H O
12
100
6 (68)
2
2
2
a
The conditions: the salt of the nitro compound (2—5 mmol), NaN (5 equiv. in entries 1—18 and 10 equiv. in entries 19—20),
3
CH Cl (20—30 mL), and water (10—15 mL) were used; 8—10 °C, vigorous stirring; the undivided or divided cell with 0.1 M H SO
4
2
2
2
–
2
–2
as the catholyte; the current density was 100 mA cm for the undivided cell and 50 mA cm for the divided cell.
The yields are given with respect to the converted salt of the nitro compound.
,2ꢀDiazidopropane (7) was also obtained in 14% yield.
Methyl 4ꢀoxohexanoate was also obtained in 26% yield.
b
c
2
d

2560
Russ.Chem.Bull., Int.Ed., Vol. 53, No. 11, November, 2004
Ogibin et al.
nitropropane (4b) was obtained in 45—50% yield. When
azido isomers (6b) (see Table 1, entries 19, 20). Earlier,
compounds 5 and 6 were alternatively synthesized by oxiꢀ
the salt of 1ꢀnitrohexane and NaN were simultaneously
3
1
subjected to electrolysis, the yield of 1ꢀazidoꢀ1ꢀnitroꢀ
hexane (4b) increased to 67% and the degree of converꢀ
sion of the starting salt reached 98% since Q was 6 F mol–1
dative azidation of salts 2 and 3 with K Fe(CN) . Our
3
6
electrochemical method for the synthesis of compounds 5
and 6 has substantial advantages over that known techꢀ
nique: the excess of azide anions is reduced by half, the
toxic inorganic oxidant used in a tenfold excess is reꢀ
placed by ecologically safe electric current, and the target
compounds are obtained in good yields.
(
see Table 1, entry 9). Most probably, the absence of
products from electrooxidative coupling of salts of priꢀ
mary nitroalkanes with NaN in an undivided cell with
3
the twoꢀphase CH Cl —water system is due to electroꢀ
2
2
generation of NaOH, which favors deprotonation of
One can assume that electrooxidative coupling of salts
1
1
ꢀazidoꢀ1ꢀnitroalkanes. The resulting Na salts of 1ꢀazidoꢀ
ꢀnitroalkanes are very unstable; for instance, the halfꢀ
of nitro compounds with NaN and oxidative coupling of
3
these substrates follow the same radical nucleophilic subꢀ
3
,4
life period of the Na salt of 1ꢀazidoꢀ1ꢀnitroethane at pH 10
is 10 min, nitrogen evolving on its decomposition. This
assumption was supported by successful electrooxidative
coupling of salts of primary nitroalkanes with NaN in a
stitution mechanism (SRN1). First, radicals are generꢀ
ated in the oneꢀelectron oxidation of the substrate with
the lowest oxidative potential; in our case, this is azide
2
8
anion with E1/2 = 0.20 V (for salt anions of nitro comꢀ
3
9
divided cell with 0.1 M H SO as a catholyte (with 0.1 M
pounds, E1/2 ≈ 0.90 V ). Then, azide radicals rapidly add
2
4
NaOH as a catholyte, no 1ꢀazidoꢀ1ꢀnitroalkanes were
obtained).
Unlike salts of primary nitroalkanes 1a—c, salts of
secondary nitro compounds, namely, 2ꢀnitropropane (1d),
to salts of nitro compounds, which are active radical acꢀ
1
0
ceptors, to form stable radical anions. When oxidized,
they transform into geminal azidonitro compounds. Some
azide radicals undergo recombination to give molecular
nitrogen (Scheme 2).
4
ꢀnitroheptanꢀ2ꢀone (1e), nitrocyclohexane (1g), nitroꢀ
cycloheptane (1h), and 2ꢀnitronorbornane (1i), can react
with NaN to form the corresponding geminal azidonitro
3
Scheme 2
compounds under the conditions of twoꢀphase undivided
electrolysis. The moderate yield (45%) of 2ꢀazidoꢀ2ꢀ
nitropropane (4d) under these conditions is explained by
its further azidation into 2,2ꢀdiazidopropane (7); a simiꢀ
lar transformation occurs when compound 4d is obtained
4
from salt 1d in the K Fe(CN) —NaN system. The couꢀ
3
6
3
pling of salts 1e and 1g—i with NaN at Q = 4—6 F/mol
3
of the salt afforded the corresponding geminal azidonitro
compounds in 78—92% yields; the degrees of conversion
of salts 1e and 1g—i were 76—100% (see Table 1, enꢀ
tries 10, 12—17). A simultaneous electrolysis of salt 1g
and NaN in a divided cell with a twoꢀphase anolyte
3
–
1
allowed Q to be reduced from 6 to 4 F mol for the
complete conversion of the salt (entry 15). Undivided
electrolysis of methyl 4ꢀnitrohexanoate (1f) in the presꢀ
ence of NaN in a CH Cl —water system gave a mixture
The evidence for the above mechanism is that the
electrolysate contains no vicinal dinitro compounds
formed by dimerized αꢀnitroalkyl and αꢀnitrocycloalkyl
radicals; their formation could be expected as the result of
electrooxidation of nitro compound anions under the choꢀ
sen electrolysis conditions.9
3
2
2
of products because of the hydrolysis of the ester group;
for this reason, the reaction with compound 1f was carꢀ
ried out in MeOH (entry 12).
,11
The electrooxidation of salts of 1,4ꢀdinitrocyclohexane
(
2) and 2,5ꢀdinitronorbornane (3) in the undivided cell
The geminal azidonitroalkanes and azidonitrocycloꢀ
alkanes obtained are colorless or slightly yellow mobile
liquids, while diazidodinitrocycloalkanes 5a and 6a are
colorless crystalline substances. Their structures were deꢀ
with NaN in a twoꢀphase system proceeds similarly to
that of salts of nitrocyclohexane (1g), nitrocycloheptane
(
electrooxidative coupling with NaN in a molar ratio of
1
dinitrocyclohexane (5) in 75% yield as a ∼ 2.5 : 1 mixture
of transꢀ (5a) and cisꢀisomers (5b) and 2,5ꢀdiazidoꢀ2,5ꢀ
dinitronorbornane (6) in 68% yield as a ∼ 2 : 1 mixture of
exoꢀ2ꢀazidoꢀexoꢀ5ꢀazido (6a) and exoꢀ2ꢀazidoꢀendoꢀ5ꢀ
3
1h), and 2ꢀnitronorbornane (1i). For instance, their
1
13
termined from H and C NMR and IR spectra and
confirmed by elemental analysis data. All the compounds
3
–
1
: 10 and Q = 8—12 F mol gave 1,4ꢀdiazidoꢀ1,4ꢀ
–
1
obtained absorb at 2120—2130 (N ) and 1540—1560 cm
3
13
(NO ); the C NMR spectra of azidonitroalkanes and
2
azidonitrocycloalkanes show characteristic signals at
δ 92—97 and 98—109 for tertiary and quaternary C atoms,

Synthesis of geminal azidonitro compounds
Russ.Chem.Bull., Int.Ed., Vol. 53, No. 11, November, 2004 2561
1a,b and 6 F mol–1 for 1c); when a lesser quantity of electricity
respectively. Azidonitroalkanes and azidonitrocycloꢀ
alkanes remain unchanged when kept in a refrigerator at
was passed, the residue (after removal of CH Cl ) was a mixture
2
2
of compounds 4a—c with the starting reagents 1a—c. The mixꢀ
5
°C for at least three months, while crystalline dinitroꢀ
1
ture was analyzed by H NMR spectroscopy with 1,2ꢀdichloroꢀ
diazides 5a and 6a are stable at room temperature.
Thus, the electrooxidative coupling of salts of nitro
compounds with azide anions is an efficient route to gemiꢀ
nal azidonitroalkanes, azidonitrocycloalkanes, and diꢀ
azidodinitrocycloalkanes.
ethane as the internal standard to determine the degree of conꢀ
version of the starting salt of nitro compound and the yields of
the products. The results obtained are summarized in Table 1.
1
13
Products 4a—c were identified from H and C NMR and IR
spectra. 1ꢀAzidoꢀ1ꢀnitroethane (4a) and 1ꢀazidoꢀ1ꢀnitropropane
(
4b) were also isolated by vacuum distillation of electrolysis
products obtained with the use of a larger membrane electrolyzer.
It should be noted that azidonitroalkanes and azidonitroꢀ
cycloalkanes cannot be isolated or purified by column chromaꢀ
tography because of their decomposition into the corresponding
Experimental
Caution! Azidonitro compounds and possible byꢀproducts are
toxic and explosive; therefore, respective precautions must be used.
1
,4
carbonyl compounds in contact with silica gel.
1
13
H and C NMR spectra were recorded on Bruker ACꢀ200,
Synthesis of 1ꢀazidoꢀ1ꢀnitroalkanes 4a,b. Electrolysis was
carried out in a 200ꢀmL beaker charged with nitroalkane 1a,b
(40 mmol) and 1 M NaOH (40 mL). The reaction mixture was
Bruker WMꢀ250, and Bruker AMꢀ300 spectrometers in CDCl3.
IR spectra were recorded on a Specordꢀ80 spectrometer (thin
film). Laboratory B5ꢀ44 and B5ꢀ50 power suppliers with the
output current stabilization were used as dc generators. The
quantity of passed electricity was measured with a digital elecꢀ
tronic coulometer (limiting measurable current 20 A (Special
Designing Bureau, Institute of Organic Chemistry, Russian
Academy of Sciences)). GLC analysis was performed on a
Varianꢀ3700 chromatograph (flame ionization detector, glass
columns 2×0.003 m, stationary phases 5% SEꢀ30 and 5% XEꢀ60
on Chromaton NꢀAW). TLC analysis was carried out on Silufol
UVꢀ254 plates. Silica gel L (40/100 µm) was used for flash
chromatography. Methanol was dehydrated by distillation
over magnesium methoxide. Commercial nitroethane, 1ꢀ and
stirred to complete homogenization (∼ 1 h) and then NaN (7.8 g,
3
120 mmol) and CH Cl (40 mL) were added. The beaker was
2
2
cooled in an ice bath and fitted with a platinum anode (4×2 cm)
and a cylindrical flatꢀbottom ceramic cup (3×15 cm) as a cathode
compartment. A stainless steel cathode (4×2 cm) was placed in
the cup and conc. H SO (2.1 mL) in 20 mL of water was added
2
4
as a catholyte. The anolyte was vigorously stirred during elecꢀ
–
2
trolysis; the anodic current density was 200 mA cm and Q =
3 F mol– . After Q = 2 F mol was passed, conc. H SO (1 mL)
1
–1
2
4
in 10 mL of water was added to the catholyte. After the elecꢀ
trolysis was completed, the anolyte was acidified with conc. HCl
(1 mL), the organic layer was separated, and the organic maꢀ
terial from the aqueous layer was extracted with CH Cl
2
ꢀnitropropanes, nitrohexane, and nitrocyclohexane were purꢀ
chased from Aldrich.
Nitrocycloheptane, 2ꢀnitronorbornane, 1,4ꢀdinitroꢀ
2
2
(2×20 mL). The combined organic phase was washed with water
1
2
13
(2×20 mL), dried with MgSO , and concentrated in vacuo at
4
cyclohexane,1
3,14
and 2,5ꢀdinitronorbornane13 were prepared
by oxidation of the corresponding ketone and diketone oximes
with mꢀchloroperoxybenzoic acid in acetonitrile in the presence
of Na HPO . 5ꢀNitroheptanꢀ2ꢀone and methyl 4ꢀnitrohexanoate
room temperature. The residue was distilled in vacuo in a water
bath heated to 80 °C.
2
1ꢀAzidoꢀ1ꢀnitroethane (4a). Yield 40%, b.p. 56 °C (10 Torr),
nD20 1.4527. H NMR, δ: 1.78 (d, 3 H, J = 6.6 Hz); 5.31 (q, 1 H,
1
2
4
1
5—17
13
were synthesized according to known procedures.
J = 6.6 Hz). C NMR, δ: 18.36 (CH ); 92.29 (CH).
3
Electrooxidative coupling of Na salts of nitro compounds with
1ꢀAzidoꢀ1ꢀnitropropane (4b). Yield 40%, b.p. 45 °C (1 Torr),
nD20 1.4467. IR, ν/cm : 2124 (N ), 1560 (NO ). H NMR, δ:
–1
1
NaN in a divided cell with a twoꢀphase system (general proceꢀ
3
3 2
dure). A nitro compound (2—5 mmol) was added to 3 M aqueꢀ
ous NaOH (1 equiv.) and the reaction mixture was stirred to a
complete conversion of the substrate into its salt (1—2 h). The
resulting solution was diluted with water, saturated aqueous
NaHCO , or 1 M Na HPO ; NaN (5 equiv.) and methylene
1.04 (t, 3 H, J = 7.2 Hz); 1.95—2.27 (m, 2 H); 5.17 (t, 1 H, J =
13
6.5 Hz). C NMR, δ: 8.71 (CH ); 26.00 (CH ); 97.03 (CH).
3
2
Found (%): C, 27.50; H, 4.61; N, 43.18. C H N O . Calcuꢀ
3
6
4
2
lated (%): C, 27.70; H, 4.65; N, 43.06.
–
1
1ꢀAzidoꢀ1ꢀnitrohexane (4c). IR, ν/cm : 2124 (N ), 1564
3
2
4
3
3
1
dichloride (20—30 mL) were added to prepare an anolyte. Elecꢀ
trolysis was carried out in a cell containing a ceramic cup, a
(NO ). H NMR, δ: 0.89 (t, 3 H, J = 7.2 Hz); 1.22—1.50
2
(m, 6 H); 1.85—2.21 (m, 2 H); 5.19 (t, 1 H, J = 6.6 Hz).
2
2
13
platinum anode (4 cm ), and a stainless steel cathode (4 cm ).
The anolyte was vigorously stirred under the conditions speciꢀ
fied in Table 1 and cooled in an ice bath. The catholyte was
C NMR, δ: 13.68 (C(6)); 22.15 (C(5)); 24.10 (C(3)); 30.67,
32.34 (C(2), C(4)); 96.00 (C(1)). Found (%): C, 41.62; H, 6.88;
N, 32.78. C H N O . Calculated (%): C, 41.85; H, 7.02;
6
12
4
2
0
.1 M H SO . To monitor the course of the reaction, an aliquot
N, 32.54.
2
4
of the aqueous phase of the anolyte was acidified with AcOH,
organic material was extracted with CH Cl , and the extract was
Electrooxidative coupling of Na salts of nitro compounds with
NaN in an undivided cell in a twoꢀphase system (general proceꢀ
2
2
3
analyzed by GLC. After the electrolysis was completed, the
anolyte was acidified with AcOH (1 mL), the organic layer was
separated, and the product from the aqueous layer was extracted
dure). A nitro compound (2 mmol) was mixed with CH Cl
2
2
(20 mL) and 0.2 M aqueous NaOH (1 equiv., 10 mL). The
reaction mixture was stirred to a complete conversion into the
corresponding salt (1—3 h; the presence of the nitro compound
in the organic phase was monitored by GLC) and then NaN3
(5 equiv.) was added. The resulting mixture was transferred to
with CH Cl2 (2×20 mL). The combined organic phase was
2
washed with water (2×20 mL), dried with MgSO , and concenꢀ
4
trated in a rotary evaporator in vacuo at room temperature. Such
2
treatment of the electrolysate gave sufficiently pure nitroazides
an electrolyzer with a platinum anode (4 cm ) and a stainless
a—c (quantity of the electricity passed was Q = 3 F mol– for
1
steel cathode (4 cm ) spaced at 10 mm. Direct current was
2
4

2562
Russ.Chem.Bull., Int.Ed., Vol. 53, No. 11, November, 2004
Ogibin et al.
1
passed under the conditions specified in Table 1. To monitor the
course of the reaction, an aliquot of the aqueous phase was
acidified with AcOH, organic material was extracted with
CH Cl , and the extract was analyzed by GLC. After the elecꢀ
2,5ꢀDiazidoꢀ2,5ꢀdinitronorbornane (6). A ∼ 2 : 1 mixture of
exoꢀ2ꢀazidoꢀexoꢀ5ꢀazido (6a) and exoꢀ2ꢀazidoꢀendoꢀ5ꢀazido isoꢀ
mers (6b) (NMR data); isomer 6a was isolated by recrystallizaꢀ
tion from chloroform. exo,exoꢀ2,5ꢀDiazidoꢀendo,endoꢀ2,5ꢀ
2
2
1
1
trolysis was completed, the organic layer was separated and
organic material was extracted from the aqueous layer with
CH Cl (20 mL). The combined organic phase was washed with
dinitronorbornane (6a), m.p. 92—95 °C. H NMR, δ: 2.05 (dd,
2 H, Hexo(3), J = 15.8 Hz, J = 5.5 Hz); 2.16 (t, 2 H, H(7),
J = 1.9 Hz); 2.55 (dt, 2 H, Hendo(3), J = 15.8 Hz, J = 1.3 Hz);
2
2
13
water (2×20 mL), dried with MgSO , and concentrated in a
3.06 (m, 2 H, H(4)). C NMR, δ: 34.01 (CH ); 36.98 (CH );
2 2
4
rotary evaporator in vacuo at room temperature to give virtually
pure compounds 4e, 4g—i, 5, and 6. 2ꢀAzidoꢀ2ꢀnitropropane
45.60 (CH); 106.00 (s). exoꢀ2ꢀAzidoꢀendoꢀ5ꢀazidoꢀendoꢀ2ꢀnitroꢀ
exoꢀ5ꢀnitronorbornane (6b) (in a mixture with isomer 6a).
13
(
4d) was obtained as a mixture with 2,2ꢀdiazidopropane (7);
C NMR, δ: 34.24 (CH ); 36.90 (CH ); 45.89 (CH); 106.68 (s).
2 2
4
1
attempts to separate the mixture by column chromatography
failed because of the decomposition of both components. The
aqueous phase was acidified with AcOH (1 mL) to convert the
unreacted salt into the starting nitro compound and organic
material was extracted with CH Cl (3×20 mL). The combined
2,2ꢀDiazidopropane (7). H NMR, δ: 1.52 (s, 6 H).
13
C NMR, δ: 25.80 (CH ); 80.04 (s).
3
Electrooxidative coupling of the Na salt of methyl 4ꢀnitroꢀ
hexanoate (1f) with NaN in methanol (see Table 1, entry 12).
3
Ester 1f (2 mmol) was mixed with 0.1 M MeONa (1 equiv.) in
2
2
extracts were dried with MgSO and concentrated in a rotary
methanol and the mixture was stirred to its complete conversion
4
evaporator in vacuo. The residue was analyzed by GLC with
dodecane or hexadecane as the internal standard to determine
the degree of conversion of the starting salts of nitro compounds.
The results obtained are given in Table 1. Products 4—7 were
into the salt (0.5—1 h). Then NaN (5 equiv.) was added and
3
electrolysis was carried out and monitored as described above.
After the electrolysis was completed, the reaction mixture was
diluted with water (40 mL) and acidified with acetic acid (1 mL)
to convert the unreacted salt into the starting nitro compound.
Organic material was extracted with CH Cl (3×20 mL) and the
1
13
identified from their H and C NMR and IR spectra.
ꢀAzidoꢀ2ꢀnitropropane (4d).4 1H NMR, δ: 1.80 (s, 6 H).
C NMR, δ: 24.68 (CH ), 100.0 (s).
2
2
2
13
combined extracts were washed with water (2×20 mL), dried
3
1
ꢀAzidoꢀ1ꢀnitrocyclohexane (4g). IR, ν/cm–1: 2122 (N ),
1
,4
with MgSO , and concentrated in a rotary evaporator in vacuo
3
4
1
1
550 (NO ). H NMR, δ: 1.26—1.43 (m, 1 H); 1.45—1.63
at room temperature. The residue was analyzed by GLC with
dodecane as the internal standard and by NMR spectroscopy
with 1,2ꢀdichloroethane as the internal standard to determine
the degree of conversion of the starting salt of nitro compound
and the yields of the products. The results obtained are given in
2
(
(
m, 2 H); 1.63—1.85 (m, 3 H); 2.04 (d, 2 H, J = 12.5 Hz); 2.18
dt, 2 H, J = 3.7 Hz, J = 13.2 Hz). 1 C NMR, δ: 22.37 (C(3));
3
2
4.00 (C(4)); 33.16 (C(2)); 103.00 (C(1)).
ꢀAzidoꢀ1ꢀnitrocycloheptane (4h). IR, ν/cm : 2124 (N ),
–
1
1
3
1
1
13
1
552 (NO ). H NMR, δ: 1.50—1.83 (m, 8 H); 2.06 (dd, 2 H,
Table 1. Product (4f) was identified from its H and C NMR
spectra.
2
J = 14.5 Hz, J = 7.8 Hz); 2.38 (dd, 2 H, J = 14.5 Hz, J =
1
3
9
1
.9 Hz). C NMR, δ: 22.44 (C(4)); 28.44 (C(3)); 37.28 (C(2));
Methyl 4ꢀazidoꢀ4ꢀnitrohexanoate (4f) (in a mixture with meꢀ
1
07.24 (C(1)). Found (%): C, 45.50; H, 6.42; N, 30.70.
thyl 3ꢀoxohexanoate). H NMR, δ: 1.03 (t, 3 H, J = 7.2 Hz);
C H N O . Calculated (%): C, 45.65; H, 6.57; N, 30.42.
2.16 (q, 2 H, J = 7.2 Hz); 2.27—2.55 (m, 4 H), 3.68 (s, 3 H,
OCH ). C NMR, δ: 7.74 (CH ); 27.86, 30.06, 30.14 (CH );
3 3 2
51.61 (OCH ); 105.63 (s), 171.72 (CO).
3
7
12
4
2
13
2
ꢀAzidoꢀ2ꢀnitronorbornane (4i). A 5 : 1 mixture of isomers
(1
H NMR data). IR, ν/cm : 2124 (N ), 1548 (NO ). H NMR,
–1
1
3
2
δ: 1.08—1.23 (m, 1 H); 1.29—1.43 (m, 1 H); 1.43—1.56 (m, 1 H);
1
2
2
1
.56—1.76 (m, 3 H); 1.76—1.87 (m, 1 H); 2.40—2.51 (m, 2 H);
This work was financially supported by the Russian
Foundation for Basic Research (Project No. 03ꢀ03ꢀ32488)
and the State Foundation for Support of Leading Scienꢀ
tific Schools of Russia (Grant 02121ꢀ2003ꢀ3).
13
.82 and 2.94* (both s, total 1 H). C NMR, δ: 23.25*, 23.42,
6.85, 27.60*, 36.56, 37.51*, 38.18, 39.93, 40.94*, 46.01, 46.26*,
09.13, 109.69*. Found (%): C, 45.95; H, 5.42; N, 30.90.
C H N O . Calculated (%): C, 46.15; H, 5.53; N, 30.75.
7
10
4
2
1
5
ꢀAzidoꢀ5ꢀnitroheptanꢀ2ꢀone (4e). H NMR, δ: 1.03 (t, 3 H,
13
J = 7.2 Hz); 2.15 (s, 3 H); 2.10—2.70 (m, 6 H). C NMR, δ:
.73 (CH ), 28.73 (CH ), 29.45 (CH CO); 30.13 (CH ); 36.75
References
7
3
2
3
2
(
CH CO); 105.91 (s); 205.24 (CO). Found (%): C, 41.73;
2
1
2
. G. K. S. Prakash, J. J. Struckhoff, Jr., K. Weber,
A. Schreiber, R. Bau, and G. A. Olah, J. Org. Chem., 1997,
62, 1872.
. I. V. Tselinskii, S. F. Mel´nikova, and S. A. Fedotov, Izv.
Akad. Nauk, Ser. Khim., 2002, 1354 [Russ. Chem. Bull., Int.
Ed., 2002, 51, 1466].
H, 5.82; N, 28.22. C H N O . Calculated (%): C, 42.00;
H, 6.04; N, 27.99.
,4ꢀDiazidoꢀ1,4ꢀdinitrocyclohexane (5). A ∼ 2.5 : 1 mixture
of transꢀ and cisꢀisomers (NMR data); the transꢀisomer was
isolated by recrystallization from chloroform. transꢀ1,4ꢀDiazidoꢀ
7
12
4
3
1
1
1
1
,4ꢀdinitrocyclohexane (5a), m.p. 135—137 °C (decomp.). IR,
–
1
1
3. S. I. AlꢀKhalil and W. R. Bowman, Tetrahedron Lett., 1982,
43, 4513.
ν/cm : 2132 (N ), 1544 (NO ). H NMR, δ: 2.30, 2.50 (both d,
4
3
2
13
H each, J = 9 Hz). C NMR, δ: 17.70 (CH ); 98.64 (s).
2
4
. S. I. AlꢀKhalil and W. R. Bowman, J. Chem. Soc., Perkin
Trans. 1, 1986, 555.
cisꢀ1,4ꢀDiazidoꢀ1,4ꢀdinitrocyclohexane (5b) (in a mixture with
1
isomer 5a). H NMR, δ: 2.08—2.38 (m, 4 H); 2.38—2.68
13
5. B. G. Christensen and L. D. Cama, Ger. Offen., 2 151 036;
Chem. Abstr., 1972, 77:126616.
(
m, 4 H). C NMR, δ: 17.52 (CH ).
2
6
. S. M. Wright and G. A. Ward, J. Electrochem. Soc.,
1965, 2, 11.
*
The signals for the minor isomer.

Synthesis of geminal azidonitro compounds
Russ.Chem.Bull., Int.Ed., Vol. 53, No. 11, November, 2004 2563
7
. N. L. Weinberg and H. R. Weinberg, Chem. Rev., 1968,
8, 489.
13. G. A. Olah, P. Ramaiah, G. K. S. Prakash, and R. Gilardi,
J. Org. Chem., 1993, 58, 763.
6
8
9
. R. Haul and E. Scholz, Naturwissenschaften, 1944, 32, 294.
. S. Wawszonek and T.ꢀY. Su, J. Electrochem. Soc., 1973,
1
14. A. T. Nielson, J. Org. Chem., 1962, 27, 1993.
15. K. Fukunaga and M. Kimura, J. Chem. Soc. Jpn, Chem. Ind.
Chem., 1982, 1499.
16. D. W. Chasar, Synthesis, 1982, 841.
17. G. Rosini, E. Marotta, R. Ballini, and M. Petrini, Synthesis,
1986, 237.
20, 745.
0. B. C. Gilbert and R. O. C. Norman, Can. J. Chem., 1982,
0, 1379.
1. V. A. Kokorekina, V. A. Petrosyan, and L. G. Feoktistov,
Elektrosintez monomerov [Electrochemical Synthesis of Monoꢀ
mers], Nauka, Moscow, 1980, 83 (in Russian); S. T. Bahner,
Ind. Eng. Chem., 1952, 44, 317.
1
1
6
1
2. N. Kornblum, H. O. Larson, R. K. Blackwood, D. D.
Mooberry, E. P. Oliveto, and G. E. Graham, J. Am. Chem.
Soc., 1956, 78, 1497.
Received June 29, 2004;
in revised form October 5, 2004