Synthesis and reactivity of carbohydroximoyl azides: I. Aliphatic and aromatic carbohydroximoyl azides and 5-substituted 1-hydroxytetrazoles based thereon

Article abstract of DOI:10.1023/A:1012453012799

Chlorination of 1-hydroxyiminopentane gave 1-chloro-1-nitrosopentane which reacted with sodium azide in DMF to form pentanohydroximoyl azide. The azidation of benzohydroximoyl chlorides was always accompanied by decomposition to benzonitriles. Treatment of carbohydroximoyl azides in ether with gaseous hydrogen chloride afforded 5-butyl-and 5-aryl-1-hydroxytetrazoles which reacted with acetic anhydride to form the corresponding acetates.

Full text of DOI:10.1023/A:1012453012799

Russian Journal of Organic Chemistry, Vol. 37, No. 3, 2001, pp. 430 436. Translated from Zhurnal Organicheskoi Khimii, Vol. 37, No. 3, 2001,
pp. 455 461.
Original Russian Text Copyright
2001 by Tselinskii, Mel’nikova, Romanova.
Synthesis and Reactivity of Carbohydroximoyl Azides:
I. Aliphatic and Aromatic Carbohydroximoyl Azides
and 5-Substituted 1-Hydroxytetrazoles Based Thereon*
I. V. Tselinskii, S. F. Mel’nikova, and T. V. Romanova
St. Petersburg State Institute of Technology, Moskovskii pr. 26, St. Petersburg, 198013 Russia
e-mail: ivts@tu.spb.ru
Received December 15, 1999
Abstract Chlorination of 1-hydroxyiminopentane gave 1-chloro-1-nitrosopentane which reacted with sodium
azide in DMF to form pentanohydroximoyl azide. The azidation of benzohydroximoyl chlorides was always
accompanied by decomposition to benzonitriles. Treatment of carbohydroximoyl azides in ether with gaseous
hydrogen chloride afforded 5-butyl- and 5-aryl-1-hydroxytetrazoles which reacted with acetic anhydride to
form the corresponding acetates.
It was recently reported that N-hydroxytetrazoles
are effective acylation catalysts in the synthesis of
peptides [1]. However, these compounds are very few
in number. Derivatives of 1-hydroxytetrazole with
heterocyclic and especially aliphatic substituents
have been studied very poorly. The most studied are
1-hydroxytetrazoles having an aromatic substituent in
position 5. Presumably, this is the result of relatively
easy preparation and stability of precursors of 5-aryl-
1-hydroxytetrazoles, benzohydroximoyl oximes, as
well as of accessibility of starting compounds.
chlorides in an inert solvent or without a solvent.
The cyclyzation was also observed on treatment of
carbohydroximoyl azides with trifluoroacetic acid;
however, in this case the isomerization rate was lower
by a factor of 30. It was presumed that the cyclization
is initiated by protonation of the azide nitrogen atom
attached to carbon (which has the greatest electron
1
density) [9]. Dignam et al. [10] studied the H NMR
spectra of isomeric oximes and showed that reactions
of carbohydroximoyl chlorides with sodium azide
are stereoselective: Only the Z-isomers of carbo-
hydroximoyl azides are formed (Scheme 1).
Carbohydroximoyl azides are usually synthesized
by reaction of alkali metal azides with nitrile oxides
generated from carbohydroximoyl chlorides. The
structure of the products, whether they are carbo-
hydroximoyl azides or 1-hydroxytetrazoles, have long
been the matter of discussion [2, 3]. Only in 1960s,
rigorous proofs for the carbohydroximoyl structute
were reported for the first time [4 6]. It was shown
that carbohydroximoyl azides are fairly stable com-
pounds which do not undergo spontaneous cyclization
to 1-hydroxytetrazoles [4]. A possible reason is elec-
tron-acceptor character of the OH group which hinders
-electron density transfer from the C N bond to
the azide nitrogen atom, thus preventing the cycliza-
tion [7]. Later on, Plenkiewicz [8, 9] found that
aromatic carbohydroximoyl azides can readily be con-
verted into 1-acyloxytetrazoles by the action of acyl
____________
Scheme 1.
The Z-isomer is likely to be stabilized by formation
of intramolecular hydrogen bond, and it can be stored
for a relatively long time. Treatment of Z-isomer
with gaseous hydrogen chloride in ether results in
*
This study was financially supported by the Russian Founda-
tion for Basic Research (project no. 99-03-33085a).
1070-4280/01/3703-0430$25.00 2001 MAIK Nauka/Interperiodica

SYNTHESIS AND REACTIVITY OF CARBOHYDROXIMOYL AZIDES: I.
431
Scheme 2.
isomerization into unstable E-isomer which readily
undergoes cyclization to 1-hydroxytetrazole.
The structure of azide I is confirmed by the pres-
ence in its IR spectrum of a strong absorption band at
1
1
2120 cm due to azido group. In the H NMR spec-
trum we observed a signal at 9.4 ppm due to proton
of the hydroxyimino group. Azide I is fairly stable
in such organic solvents as diethyl ether, DMF, and
acetone (the azide band in the IR spectrum of a solu-
tion of I in DMF is retained at least for a weak),
but it decomposes in chlorinated hydrocarbons. After
isolation from solution, azide I undergoes rearrange-
ment into 5-butyl-1-hydroxytetrazole (II) in a few
minutes; presumably, this process is promoted by acid
impurities formed by partial decomposition of I.
This fact provides an additional support to the acid
catalysis of the rearrangement of carbohydroximoyl
azides into 1-hydroxytetrazoles, for basic solvents
(such as DMF) stabilize the azide structure.
We have studied the possibility of synthesizing
pentanohydroximoyl azide (I) and its isomerization
to 5-butyl-1-hydroxytetrazole (II). Compound I was
obtained by the traditional scheme including the
synthesis of pentanohydroximoyl chloride (III) via
chlorination of oxime IV and treatment of III with
sodium azide (Scheme 2). The chlorination of IV
was carried out in various solvents (diethyl ether,
methylene chloride, dilute hydrochloric acid, etc.) at
8 to 10 C. It is generally assumed that halogenation
of oximes involves intermediate formation of the cor-
responding 1-chloro-1-nitroso derivative which under-
goes fast rearrangement into carbohydroximoyl
chloride [11]. However, regardless of the solvent, the
chlorination of oxime IV stopped at the stage of
formation of nitroso chloride V which was stable for
24 h at room temperature (no spontaneous isomeriza-
tion to carbohydroximoyl chloride V occurred). The
1H NMR spectrum of the chlorination product con-
tained signals at 0.9 (3H, CH3), 1.5 (4H, CH2), 2.4
(2H, CH2), and 9.9 ppm (1H, CH). On prolonged
storage of product V we observed evolution of HCl
and formation of a mixture of compounds.
The effect of the solvent is clearly observed in
the synthesis of oxalohydroximoyl diazide (VII) from
dichloride VI and NaN3 (Scheme 3).
Scheme 3.
On the other hand, heating of a solution of V in
ether containing a small amount of a basic solvent
(DMF) resulted in rearrangement to chloride III,
presumably through intermediate -chloro- -nitroso-
carbanion. The signal at 9.9 ppm, corresponding to
1
the CH proton, disappeared from the H NMR spec-
trum, and a new signal appeared at
10.9 ppm,
which belongs to the NOH proton. We succeeded in
obtaining carbohydroximoyl azide I in more than 70%
yield by treatment of chloronitrosopentane V with
sodium azide directly in dimethylformamide. The use
of methanol instead of DMF also favored isomeriza-
tion of V, but in this case the main process was its
decomposition.
When the reaction was carried out in acetone or
acetonitrile, the yield of VII was 50%; in aqueous
ethanol 76% of VII was obtained; whereas with DMF
as solvent, the yield of VII was as high as 97%.
Diazide VII is much more stable than azide I; the
former can be stored for a long time without a solvent
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 3 2001

432
TSELINSKII et al.
Scheme 4.
on exposure to air (only slight evolution of nitrogen m-nitrobenzohydroximoyl chloride (XIb) and obtained
oxides was observed). However, accumulation of
nitrogen oxides in a closed vessel could lead to un-
controllable decomposition of compound VII. Like
pentanohydroximoyl azide (I), oxalohydroximoyl di-
azide (VII) undergoes smooth isomerization to bi-
tetrazole VIII on treatment of its solution in ether
with gaseous hydrogen chloride.
about 80% of the corresponding azide XIIb. However,
after storage of product XIIb for 1 h, we observed
(TLC) appearance of a new compound, m-nitrobenzo-
nitrile (XIIIb); treatment of the latter with hydroxyl-
amine gave m-nitrobenzamide oxime. The decom-
position of azide XIIb was complete in 2 days. These
data led us to presume that the synthesis of carbo-
hydroximoyl azides is always accompanied by their
partial decomposition to the corresponding nitriles.
In fact, when aqueous alcohol was replaced by DMF,
we obtained m-nitrobenzonitrile (XIIIb) in almost
quantitative yield.
It was also interesting to examine acylation of VII.
With acetic anhydride as acylating agent we obtained
the corresponding N,N -diacetoxy derivative IX. The
reaction with acetyl chloride gave 1,1 -diacetoxy-5,5 -
bitetrazole (X) and a small amount of compound IX
(Scheme 4). In the reaction of VII with acetyl chloride
in the presence of pyridine diacetate IX was formed
as the sole product. Using thin-layer chromatography,
we have found that the acylation with acetyl chloride
initially promotes isomerization of VII into VIII,
and the latter is then acylated with excess AcCl.
We also tried to reproduce the known procedure for
preparation of benzohydroximoyl azide (XIIa) [12].
In aqueous ethanol the yield of XIIa was no more
than 50%, but in DMF we obtained 75 80% of the
target product. In both cases benzonitrile (XIIIa) was
formed as by-product (Scheme 5).
It is known that aromatic carbohydroximoyl azides
are formed in high yields (80 90%) from para-sub-
stituted benzohydroximoyl chlorides in methanol [9].
We applied the same conditions to azidation of
By azidation of p-isopropylbenzohydroximoyl
chloride (XIc) in aqueous alcohol we obtained 70
72% of p-isopropylbenzohydroximoyl azide (XIIc).
When DMF was used as solvent, we failed to isolate
Scheme 5.
R = H (a), m-NO2 (b), p-i-Pr (c).
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 3 2001

SYNTHESIS AND REACTIVITY OF CARBOHYDROXIMOYL AZIDES: I.
azide XIIc, and the major product was p-isopropyl-
EXPERIMENTAL
433
benzonitrile (XIIIc).
1
The H NMR spectra were recorded on a Perkin
Elmer R12 spectrometer (60 MHz) using HMDS as
internal reference. The IR spectra were obtained on
a UR-20 instrument from thin films on NaCl support.
The molecular weights were determined by reverse
ebullioscopy in acetonitrile.
Decomposition of benzohydroximoyl azides XII
also occurred on storage in a closed vessel. The rate
of decomposition depends on the substituent in the
benzene ring. Unsubstituted azide XIIa vigorously
decomposes with evolution of nitrogen oxides and
formation of a mixture of products, the major of
which (according to the TLC data) is benzonitrile
(XIIIa). The latter was isolated as benzamide oxime
by treatment of the decomposition product mixture
with hydroxylamine. The complete decomposition of
azide XIIb takes 2 days, and the yield of nitrile XIIIb
is almost quantitative. The process can be accelerated
by raising the temperature or dissolving in DMF or
acetonitrile. The UV spectrum of a freshly prepared
solution of m-nitrobenzohydroximoyl azide (XIIb) in
acetonitrile contains an absorption maximum at
1-Hydroxyiminopentane (IV). To a solution of
52 g (0.75 mol) of hydroxylamine hydrochloride in
70 ml of water we added with stirring below 10 C
first 24 g (0.29 mol) of freshly distilled pentanal and
then a solution of 30 g (0.75 mol) of NaOH in 40 ml
of water. The mixture was kept for 20 h, and the
precipitate was filtered off and dried in air. Yield 26 g
(93%), mp 50 52 C [13] (from hexane). IR spectrum,
1
, cm : 3264, 2960, 2944, 2928, 2872, 1664, 1460,
1
928. H NMR spectrum (acetone-d6), , ppm: 0.88 t
1
228 nm ( 17200 l mol 1 cm ). On storage of the
(3H, CH3), 1.40 m (6H, CH2), 6.60 t (1H, CH),
9.85 s (1H, NOH).
solution, the spectral pattern changes: a maximum
1
appears at 255 nm ( 11300 l mol 1 cm ), which
Chlorination of 1-hydroxyiminopentane.
a. A stream of chlorine was passed through a solution
of oxime IV in organic solvent (diethyl ether or
methylene chloride) at such a rate that the temperature
did not exceed 8 C. The reaction was assumed to be
complete when heat no longer evolved and the solu-
tion turned bright green. The mixture was washed
with water until pH 4 5 of the washings and was
dried over anhydrous MgSO4. Removal of the solvent
gave more than 87% of product V as a greenish blue
is typical of m-nitrobenzonitrile. After 12 h, the latter
maximum becomes the only present in the spectrum.
Moreover, determination of the melting point of azide
XIIb gave a value of 114 115 C which coincides
with the melting point of m-nitrobenzonitrile [13]. For
the same reason, we failed to determine the melting
point and obtain satisfactory elemental analysis of
p-isopropylbenzohydroximoyl azide (XIIc). Therefore,
azides XIIb and XIIc were transferred into ether
immediately after preparation and were treated with
gaseous hydrogen chloride to obtain the corresponding
1-hydroxytetrazoles XIVb and XIVc (Scheme 5).
liquid, n1D8 1.4580. H NMR spectrum (acetone-d6), ,
1
ppm: 0.90 t (3H, CH3), 1.50 m (4H, CH2), 2.40 m
(2H, CH2), 9.90 s (1H, CH).
Decomposition of individual carbohydroximoyl
azides to nitriles at 18 20 C was observed previously
for benzohydroximoyl [3] and 2,4,6-trimethylbenzo-
hydroximoyl azides [6]. Benzohydroximoyl azide
(XIIa) showed a similar behavior on attempted acyla-
tion with acetic anhydride or acetyl chloride. With
acetic anhydride as acylating agent we obtained only
10% of the corresponding acetate XV, whereas the
major product was benzonitrile. This is consistent
with the known data [13], according to which nitriles
are formed on dissolution of carbohydroximoyl azides
in acetic acid. The acylation with acetyl chloride gave
1-acetoxy-5-phenyltetrazole (XVI), presumably due
to liberation of hydrogen chloride during the process.
These data contradict the results reported in [9] for
acylation of para-substituted benzohydroximoyl
chlorides with benzoyl chloride, which gave the corre-
sponding benzoates in high yield [9]. 1-Hydroxy-5-
aryltetrazoles are smoothly acylated with acetic
anhydride, yielding acetates XVI (Scheme 5).
b. A stream of chlorine was passed through
a suspension of oxime IV in 3% hydrochloric acid
cooled to 0 C until exothermic reaction was over
(the temperature was maintained at 2 5 C). The
mixture was extracted with ether, and the extract was
treated as described above in a to obtain compound V
in 90% yield. Compound V was brought into reac-
tion with sodium azide without additional purification.
Reaction of 1-chloro-1-nitrosopentane (V) with
sodium azide. To a solution of 3.5 g (0.026 mol) of
compound V in 20 ml of DMF we added with stirring
at 18 20 C 2.0 g (0.03 mol) of sodium azide. A slight
exothermic effect was observed. The mixture was kept
until it showed a negative test for halogen (Beilstein
test) and was poured into water. The aqueous phase
was treated with ether, and the ether extract was
washed with water, dried over anhydrous MgSO4, and
evaporated. We isolated 2.5 g (57%) of compound I
as a light yellow liquid. After 15 min, the product
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 3 2001

434
TSELINSKII et al.
began to crystallize; the crystallization was complete
in 2 h, yielding compound II.
disappeared (TLC). The solvent was removed under
reduced pressure. Yield of VIII 4.65 g.
Oxalohydroximoyl diazide (VII). a. To a solution
of 1 g (6.3 mmol) of oxalohydroximoyl dichloride
(VI) in 60 ml of acetonitrile we added with stirring
at 20 C 1.06 g (16.3 mmol) of sodium azide. The
mixture was heated with stirring to the boiling point
and was refluxed for 30 min. It was then cooled and
poured into 200 ml of water. The resulting mixture
was left overnight, and the precipitate was filtered
off and dried in air. Yield 0.5 g.
b. The procedure was the same as in a, but DMF
(10 ml) was used as solvent. Yield of product VII
1.1 g (97%). Samples of VII obtained as described
in a and b showed no depression of the melting point.
O,O -Diacetyloxalohydroximoyl diazide (IX).
A mixture of 1.7 g (0.01 mol) of diazide VII and
35 ml of acetic anhydride was heated to 90 C, kept
for 1 h at that temperature, cooled, and poured into
250 ml of water. The precipitate was filtered off.
Yield 1.8 g.
1,1 -Diacetoxy-5,5 -bitetrazole (X). A mixture of
1 g (5.8 mmol) of diazide VII and 0.91 g (11.6 mol)
of acetyl chloride in 100 ml of benzene and 50 ml of
ether was heated to the boiling point and was refluxed
for 8 h. It was then cooled, and the solvent was
removed under reduced pressure to obtain 1.04 g of
compound X. From the mother liquor we isolated
(after recrystallization) 0.2 g (17%) of compound IX
which showed no depression of the melting point
on mixing with a sample of IX obtained as described
above.
1,1 -Dihydroxy-5,5 -bitetrazole (VIII). Gaseous
hydrogen chloride was passed through a solution of
5 g (0.0294 mol) of diazide VII in 250 ml of ether,
maintained at 18 20 C, until the initial compound
1
Yields, melting points, analytical data, and IR and H NMR spectra of compounds I, II, VII X, XIIa, XIVa XIVc, XV,
XVIa, and XVIc
Found, %
H
Calculated, %
H
M
Comp. Yield,
mp,
C
Formula
no.
%
C
N
C
N
found calcd.
I
II
57
67
Liquid
92 93
42.10
41.91
6.87
6.72
38.91
39.10
C5H10N4O
C5H10N4O
42.25
42.25
7.04
7.04
39.44
39.44
142
142
(CCl4)
159
(decomp.)
210
(decomp.)
122
(i-PrOH)
147
(heptane)
120
(heptane)
145
(H2O)
100
VII
46
83
71
70
72
60
50
20
10
80
75
13.84
11.70
28.10
28.81
52.00
52.00
36.76
58.80
54.20
52.45
58.22
0.95
3.00
2.00
2.53
3.58
3.53
2.83
5.90
4.65
3.59
5.58
66.30
55.00
44.62
44.15
34.41
34.71
30.82
27.45
26.95
27.85
22.75
C2H2N8O2
14.11
1.17
2.92
2.36
2.36
3.70
5.90
4.65
3.59
5.58
3.45
5.70
65.88
54.35
44.09
44.09
34.57
34.57
31.10
27.23
27.45
27.45
22.76
174
207
257
242
160
163
170
206
254
254
162
162
225
203
204
204
246
VIII
IX
C2H2N2O2 2H20 11.65
C6H6N8O4
C6H6N8O4
C7H6N4O
28.35
28.35
51.85
51.85
37.30
58.46
52.94
52.94
58.54
X
XIIa
XIVa
XIVb
XIVc
XV
C7H6N4O
C7H5N5O3 H2O
C10H8N4O
C9H8N4O2
C9H8N4O2
C12H14N4O2
(H2O)
147 148
(benzene)
57 58
(aq. EtOH)
54 55
XVIa
XVIc
(hexane)
59 60
(hexane)
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 3 2001

SYNTHESIS AND REACTIVITY OF CARBOHYDROXIMOYL AZIDES: I.
435
Table. (Contd.)
Comp.
no.
1
IR spectrum, , cm
1H NMR spectrum, , ppm
I
3200, 2960, 2120, 1464, 1288, 1096, 980
2960, 1456, 1344, 1336, 1304, 1272
9.4 s (1H, NOH), 2.1 M (2H, CH2), 1.4 m (4H, CH2), 0.9 t (3H,
CH3)
II
9.7 s (1H, NOH), 2.85 m (2H, CH2), 1.55 m (4H, CH2), 0.90 t
(3H, CH3)
VII
VIII
IX
3180, 2200, 2170, 2155, 1630, 1365, 1065, 12.3 d (2H, NOH)
1020, 920
3500 3000, 1415, 1380, 1280, 1200, 1125, 7.9 s (2H, OH)
1015, 800
2170, 2150, 1790, 1365, 1290, 1070, 1045, 2.27 s (6H, CH3)
1005, 955, 905
X
1860, 1435, 1370, 1270, 1190, 1155, 1110, 2.75 s (6H, CH3)
1045, 1010, 985
XIIa
XIVa
XIVb
3184, 2136, 2088, 1632, 1456, 1328, 1016, 7.65 m (2H, Harom), 7.25 m (3H, Harom) 10.55 s (1H, NOH)
948
11.1 s (1H, OH), 8.85 s (1H, OH), 8.1 m (3H, Harom), 8.05 m
(3H, Harom), 7.62 m (2H, Harom), 7.55 m (2H, Harom
)
3296, 1856, 1520, 1372, 1352, 976
8.9 s (1H, Harom), 8.45 t (2H, Harom), 7.9 t (1H, Harom), 6.6 br
(3H, NOH, H2O)
XIVc
XV
2960, 1616, 1476, 1320, 1252, 840
2184, 2120, 1776, 1592, 1556
10.2 s (1H, OH), 8.15 d (2H, Harom), 7.45 d (2H, Harom
7.90 m (2H, Harom), 7.55 m (3H, Harom), 2.2 s (3H, CH3)
)
XVIa
3426, 1956, 1828, 1552, 1472, 1208, 1132, 7.9 m (2H, Harom), 7.55 m (3H, Harom), 2.5 s (3H, CH3)
932
XVIc
7.95 m (2H, Harom), 7.45 m (2H, Harom), 2.6 s (3H, CH3)
The chlorination of benzaldehyde oximes was
performed by the procedure described above for
pentanal oxime.
halogen. The mixture was poured into 100 ml of
water, and the precipitate was filtered off and dried
in air. Yield 9 g.
m-Nitrobenzohydroximoyl azide (XIIb). To a so-
lution of 8 g (0.04 mol) of compound XIb in 50 ml of
aqueous ethanol we added at 18 20 C 5 g (0.07 mol)
of sodium azide, and the mixture was stirred until
negative Beilstein test for halogen. The mixture was
poured into 150 ml of water, and the precipitate was
filtered off and dried in air. Yield 0.7 g. IR spectrum,
Benzohydroximoyl chloride (XIa). mp 45 47 C.
1H NMR spectrum (acetone-d6), , ppm: 7.80 m (3H,
Harom), 7.31 m (2H, Harom), 11.30 s (1H, NOH).
m-Nitrobenzohydroximoyl chloride (XIb). mp
101 C (from hexane). 1H NMR spectrum (acetone-d6),
, ppm: 8.50 d (1H, Harom), 8.15 m (2H, Harom),
7.60 q (1H, Harom), 11.70 s (1H, NOH).
1
1
, cm : 3864, 2144, 1616, 1525, 1336. H NMR spe-
ctrum (acetone-d6), , ppm: 8.95 s (1H, Harom), 8.45 t
(2H, Harom), 7.8 t (1H, Harom), 10.9 s (1H, NOH).
p-Isopropylbenzohydroximoyl chloride (XIc).
1
Colorless liquid. H NMR spectrum (acetone-d6), ,
1
UV spectrum: max 228 nm, 17200 l mol 1 cm .
ppm: 7.75 d (2H, Harom), 7.20 d (2H, Harom), 2.9 s
(1H, CH), 1.25 d (6H, CH3).
Compounds XIa XIc are unstable, and they were
brought into reaction with sodium azide immediately
after preparation.
Benzohydroximoyl azide (XIIa). To a solution of
12 g (7.7 mmol) of benzohydroximoyl chloride (XIa)
in 30 ml of DMF (or aqueous ethanol) at 18 20 C
we added 6 g (9.2 mmol) of sodium azide, and the
mixture was stirred until negative Beilstein test for
m-Nitrobenzonitrile (XIIIb). To a solution of 1 g
(0.005 mol) of chloride XIb in 15 ml of DMF at
18 20 C we added 0.7 g (0.01 mol) of sodium azide,
and the mixture was stirred until negative Beilstein
test for halogen. The mixture was poured into 100 ml
of water, and the precipitate was filtered off and dried
in air. Yield 0.5 g. mp 114 116 C (from hexane). IR
1
1
spectrum, , cm : 3840, 1528, 1368, 1352. H NMR
spectrum (acetone-d6), , ppm: 8.55 d (1H, Harom),
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436
TSELINSKII et al.
8.2 m (2H, Harom), 7.8 m (1H, Harom). UV spectrum:
compound disappeared (TLC). Excess acetic anhy-
dride and volatile components were removed under
reduced pressure. Yield 0.12 g.
Acylation of 1-hydroxytetrazoles (general proce-
dure). A solution of 0.1 mol of 1-hydroxytetrazole
XIV in 15 ml of acetic anhydride was stirred at
18 20 C until the initial compound disappeared com-
pletely. Excess acetic anhydride was distilled off, and
products XVIa and XVIc were recrystallized from
hexane (see table).
1
255 nm,
11300 l mol 1 cm . Found, %:
Cm5ax6.35; H 2.67; N 19.65. C7H4N2O2. Calculated, %:
C 56.75; H 2.70; N 19.20.
m-Nitrobenzamide oxime. To a suspension of 1 g
(0.015 mol) of hydroxylamine hydrochloride in 20 ml
of ethanol we added a solution of 0.6 g (0.015 mol)
of sodium hydroxide in a minimal amount of water,
maintaining the temperature below 10 C. The precip-
itate was filtered off, 0.1 g (0.007 mol) of m-nitro-
benzonitrile (see above) was added, and the mixture
was kept at room temperature until the initial nitrile
disappeared (TLC). The mixture was evaporated under
reduced pressure, and the solid residue was treated
with acetone. Removal of the solvent gave 0.07 g
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(58%) of a slightly colored crystalline product with
1
mp 146 147 C. H NMR spectrum (acetone-d6),
,
2. Forster, H., J. Chem. Soc., 1909, vol. 95, no. 1,
ppm: 9.2 s (1H, NOH), 8.5 m (1H, arom), 8.1 m
(2H, Harom), 7.6 m (1H, Harom), 5.6 s (2H, NH2).
Found, %: C 46.83; H 3.19; N 22.9. C7H7N3O3.
Calculated, %: C 46.40; H 3.86; N 23.20.
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p-Isopropylbenzohydroximoyl azide (XIIIc). The
reaction was carried out as described above for com-
pound XIIIb using 2 g (0.01 mol) of chloride XIa
and 1 g (0.015 mol) of sodium azide in 15 ml of
aqueous ethanol. Yield 1.5 g (60%). IR spectrum, ,
5. Chang, M.S. and Matuszko, A.J., J. Org. Chem.,
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1
7. Bithin, M.E.C., Miller, J., and Paul, D.B., The
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cm : 2968, 2336, 2320, 2224, 2024, 1608, 1544,
1504, 1492, 1464, 1440, 1416. Product XIIIc was
unstable, and we failed to analyze it. Immediately
after preparation, it was dissolved in ether and sub-
jected to isomerization by passing gaseous HCl.
Isomerization of benzohydroximoyl azides into
1-hydroxy-5-aryltetrazoles (general procedure).
Gaseous hydrogen chloride was passed through a so-
lution of azide XII in ether until the initial compound
disappeared (TLC). The mixture was evaporated, and
the solid residue was recrystallized from appropriate
solvent.
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Oxides, Berlin: Springer, 1971, p. 237.
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O-Acetylbenzohydroximoyl azide (XV). A solu-
tion of 1 g (0.006 mol) of azide XII in 10 ml of acetic
anhydride was stirred at 18 20 C until the initial
13. Spravochnik khimika (Chemist’s Handbook), Nikol’-
skii, B.P., Ed., Moscow: Goskhimizdat, 1963, vol. 2,
p. 564.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 3 2001