- Email: [email protected]
The structure of arylketoximes and their iminoxy radicals
TetrahedronLetters No.27, pp. 2345-2348,1970.
THE
STRUCTURE
OF ARYLKETOXIMES
Franz Max-Planck-Institut
A.
PergamonPress. Printed in Great Britain.
AND
THEIR
IMINOXY
RADICALS
Neugebauer
ftir Medizinische
Forschung,
Heidelberg,
West
Germany
(Receivedin VK 4 May 1970; accepted for publication14 May 1970)
In view
of current
interest
of arylazoketoximes trans-anti
formazans
appeared
isomer
intramolecular
in the hydrogen
(‘>,
desirable.
a linear
hydrogen
trans-syn
bridge
bonding
in oximes,
One can conceive isomer
(3) in analogy -
(3
1
to the red trans-syn
/”
N=C
\
N=C HO ’
N=N \
structures,
a linear
isomer
with a strong
isomers
‘.
-3
'N=N
of the
\ C6H5
/N-N%C_R H *. / ‘N=N
/
4
/ H5C6
H5C3
corresponding
2
‘N=N
/
IR spectra
/”
SH5
H/“-N\\^_R
of 2,
6 and 7 (table -
to the stretching
tetrachloride
stretching
of three
of the structure
(5).
1
carbon
the study
and a trans-syn
HO
The
1)
vibration
solution of free
1) in the solid
vibrations only
bands
hydroxy-groups
phase
of strongly at 357a/cm . These
2345
show strong
associated are
near
hydroxy-groups.
observed,
results
bands
exclude
corresponding the structure
32oo/cm
In i-9 % to the 3.
2346
No.21
Arylazcketoximes bridges
associate
and probably
The chemical distinguish
in the solid phase via strong
give dimers
in the form
for the trans-anti
isomer
of -1 and -2: in DMSO
1 and g.
supported
(3
two different
1.
OH-signals
OH-
one to
12.66
6,H=
are mixtures
(5) and phenylazo-methyl-
This assignment
of H and OH at ,‘C = N ,3
allows
z (table 1) is a mixture of 1 and
- 9.38
is additionally = 3.28
[ppm],
‘4).
OH
,LOH) assoc.
3575/cm
326a/cm
12.66
6
H3C
‘)
3575/cm
32oo/cm
12.58
7
H5C6
‘)
3570/cm
33 1o/cm
12.52,
iminoxy
tetra-acetate
of these oximes
radicals, in methylene
in benzene at 40°C
which can also be generated dichloride
solution
1 and table 2) show two large
nitrogen
Surprisingly,
the mixture
of trans-anti
H5C6
by l5 N labeling
8)
splittings
HO-N=C-15N=N-C6H5
(2: 1)
radical
7)
with lead
. The ESR spectra
in the range of 20 and 12 gauss. isomers
The assignment
of arylazo-aryl-ketoximes of the nitrogen
splittings
8 and 9.
C6H4N02-
I
11.35
by di-p-tolylaminyl
in a flow system
in the oximes
d[wml
by oxidation of the oximes
and trans-syn
only one type of iminoxy radicals.
been accomplished
-8
arylazo-aryl-ketoximes
isomers. J
(DMSO)
shift of the OH proton is expected
are abtained.
V (OH)free
H 5,
The dehydrogenation
generates
sulfoxide
oximes 2) .
IR and NMR data
5
(figure
chemical
OH * * * N hydrogen
rings like simple
phenylazc+formaldoxime
in the case of -5 by the difference
R
yields
A larger
turned out to be ptire trans-anti
typical for a cis arrangement
Table
in dimethyl
3) . As with most oximes,
2 in the ratio of 2: 1. Surprisingly, ketoxime
of six-membered
shift of the OH protons of oximes
between structure
intermolecular
HO-
15
(4)
I
N=C-N=N-C6H5
9
has
Ho.27
2341
The iminoxy radical unlabeled spl Ming
radical.
from 8 yields
The labeling
into a 27.2
Consequently
derived
15
gauss
the smaller
the same
ESR spectrwn
of the oxime nitrogen
in 9 changes
15N 14N a / a = 1.38
N-splittings
12 gauss nitrogen splitting
obtained from the the 19.7
gauss
(gyromagnetic
is due to the azenitrogen
14N -
ratio
1.40).
ccnnected
with the aryl group.
8
0
IO Gauss
‘6”6 Figure
1.
ESR spectrum generated
Table
2.
of the iminoxy radical
from
phenylazo-formaldoxime
by me oxidation of the oxime by lead tetra-acetate
in CH2C12 solution.
N-Oa
ESR data R3-C
44 \
N=N’ ‘R1 aN’
aN4
Solvent
R’
R3
CH2Cl2
C6H5
H
lo.9
19.3
CH 6 6
C6H5
C6H5
11.6
19.8
C6H5
11.8
20.3
C6H5
11.4
19.8
12.3
19.7
11.9
19.8
C6H6
C6H4N02
C6H6
C6H4mH3
- (4 ) - (4)
C6H6
C6H6
C6H4N02
C6H6
‘gH5
C6H4mH3
- (4) - (4)
aH 0.8
(5J
[gauss]
No.27,
2348
The
very
high spin
structures This
and suggests
cyclic
radicals
density
at the nitrogen
a cyclic
conformation
primarily
represented
formed.
as a hybrid
//Cl
trans-syn
The energeticly
of the structures
..
of MO
G -orbital, and which
1ies in the nodal
plane
reorientation
species.
of linear
conformation
:Y .:
iminoxy
can be
y l\
:O*
N
b
C -
spin densities
are
radical
//CL
l
components
linear
I
:g: .’k, -
the measured
excludes
the iminoxy
cyclic
N
-
main
fast
group
-b and -c.
4)J
:N\
theory,
whose
prefered E,
a
In terms
of a very
for
I //CL
t;’ _
:O.
to the aryl
conformation
be the result
I
:y
10
could
adjacent
orbitals
imply
that the unpaired
on the 0 atom
electron
and the adjacent
is in a
N atoms,
of the %-system.
References
1) D.S.Jackson, 2)
K.Nakamoto,
3)
G.G.Kleinspehn,
4)
A.J.Durbetaki Society,
5) M. Busch
J.Chem.Soc.
(B),
M.Margoshes
and R.E.Rundle,
J.A.Jung
1964,
E.Bamberger
7)
F.A.Neugebauer,
8)
B.C.Gilbert
148th National
Abstracts
and E .Meussdorffer,
6)
J.Amer.Chem.Soc.
and S.A.Studniarz,
and C.Miles,
Chicago,
19s_S, 785. ----
and W.Pemsel, Tetrahedron
and R.O.C.Norman,
J.org Meeting
.Chemistry, of the American
zz,
6480
32, -_
460 (1967).
Chemical
A-47.
J.prakt.Chem.
22,
Ber.dtsch.chem.Ges., Letters
1968, ====
J.Chem.Soc.
121 (1907). 36,
53,
2129. (B),
1966, ====
86.
62,
85 (19o3).
(1955).
THE
STRUCTURE
OF ARYLKETOXIMES
Franz Max-Planck-Institut
A.
PergamonPress. Printed in Great Britain.
AND
THEIR
IMINOXY
RADICALS
Neugebauer
ftir Medizinische
Forschung,
Heidelberg,
West
Germany
(Receivedin VK 4 May 1970; accepted for publication14 May 1970)
In view
of current
interest
of arylazoketoximes trans-anti
formazans
appeared
isomer
intramolecular
in the hydrogen
(‘>,
desirable.
a linear
hydrogen
trans-syn
bridge
bonding
in oximes,
One can conceive isomer
(3) in analogy -
(3
1
to the red trans-syn
/”
N=C
\
N=C HO ’
N=N \
structures,
a linear
isomer
with a strong
isomers
‘.
-3
'N=N
of the
\ C6H5
/N-N%C_R H *. / ‘N=N
/
4
/ H5C6
H5C3
corresponding
2
‘N=N
/
IR spectra
/”
SH5
H/“-N\\^_R
of 2,
6 and 7 (table -
to the stretching
tetrachloride
stretching
of three
of the structure
(5).
1
carbon
the study
and a trans-syn
HO
The
1)
vibration
solution of free
1) in the solid
vibrations only
bands
hydroxy-groups
phase
of strongly at 357a/cm . These
2345
show strong
associated are
near
hydroxy-groups.
observed,
results
bands
exclude
corresponding the structure
32oo/cm
In i-9 % to the 3.
2346
No.21
Arylazcketoximes bridges
associate
and probably
The chemical distinguish
in the solid phase via strong
give dimers
in the form
for the trans-anti
isomer
of -1 and -2: in DMSO
1 and g.
supported
(3
two different
1.
OH-signals
OH-
one to
12.66
6,H=
are mixtures
(5) and phenylazo-methyl-
This assignment
of H and OH at ,‘C = N ,3
allows
z (table 1) is a mixture of 1 and
- 9.38
is additionally = 3.28
[ppm],
‘4).
OH
,LOH) assoc.
3575/cm
326a/cm
12.66
6
H3C
‘)
3575/cm
32oo/cm
12.58
7
H5C6
‘)
3570/cm
33 1o/cm
12.52,
iminoxy
tetra-acetate
of these oximes
radicals, in methylene
in benzene at 40°C
which can also be generated dichloride
solution
1 and table 2) show two large
nitrogen
Surprisingly,
the mixture
of trans-anti
H5C6
by l5 N labeling
8)
splittings
HO-N=C-15N=N-C6H5
(2: 1)
radical
7)
with lead
. The ESR spectra
in the range of 20 and 12 gauss. isomers
The assignment
of arylazo-aryl-ketoximes of the nitrogen
splittings
8 and 9.
C6H4N02-
I
11.35
by di-p-tolylaminyl
in a flow system
in the oximes
d[wml
by oxidation of the oximes
and trans-syn
only one type of iminoxy radicals.
been accomplished
-8
arylazo-aryl-ketoximes
isomers. J
(DMSO)
shift of the OH proton is expected
are abtained.
V (OH)free
H 5,
The dehydrogenation
generates
sulfoxide
oximes 2) .
IR and NMR data
5
(figure
chemical
OH * * * N hydrogen
rings like simple
phenylazc+formaldoxime
in the case of -5 by the difference
R
yields
A larger
turned out to be ptire trans-anti
typical for a cis arrangement
Table
in dimethyl
3) . As with most oximes,
2 in the ratio of 2: 1. Surprisingly, ketoxime
of six-membered
shift of the OH protons of oximes
between structure
intermolecular
HO-
15
(4)
I
N=C-N=N-C6H5
9
has
Ho.27
2341
The iminoxy radical unlabeled spl Ming
radical.
from 8 yields
The labeling
into a 27.2
Consequently
derived
15
gauss
the smaller
the same
ESR spectrwn
of the oxime nitrogen
in 9 changes
15N 14N a / a = 1.38
N-splittings
12 gauss nitrogen splitting
obtained from the the 19.7
gauss
(gyromagnetic
is due to the azenitrogen
14N -
ratio
1.40).
ccnnected
with the aryl group.
8
0
IO Gauss
‘6”6 Figure
1.
ESR spectrum generated
Table
2.
of the iminoxy radical
from
phenylazo-formaldoxime
by me oxidation of the oxime by lead tetra-acetate
in CH2C12 solution.
N-Oa
ESR data R3-C
44 \
N=N’ ‘R1 aN’
aN4
Solvent
R’
R3
CH2Cl2
C6H5
H
lo.9
19.3
CH 6 6
C6H5
C6H5
11.6
19.8
C6H5
11.8
20.3
C6H5
11.4
19.8
12.3
19.7
11.9
19.8
C6H6
C6H4N02
C6H6
C6H4mH3
- (4 ) - (4)
C6H6
C6H6
C6H4N02
C6H6
‘gH5
C6H4mH3
- (4) - (4)
aH 0.8
(5J
[gauss]
No.27,
2348
The
very
high spin
structures This
and suggests
cyclic
radicals
density
at the nitrogen
a cyclic
conformation
primarily
represented
formed.
as a hybrid
//Cl
trans-syn
The energeticly
of the structures
..
of MO
G -orbital, and which
1ies in the nodal
plane
reorientation
species.
of linear
conformation
:Y .:
iminoxy
can be
y l\
:O*
N
b
C -
spin densities
are
radical
//CL
l
components
linear
I
:g: .’k, -
the measured
excludes
the iminoxy
cyclic
N
-
main
fast
group
-b and -c.
4)J
:N\
theory,
whose
prefered E,
a
In terms
of a very
for
I //CL
t;’ _
:O.
to the aryl
conformation
be the result
I
:y
10
could
adjacent
orbitals
imply
that the unpaired
on the 0 atom
electron
and the adjacent
is in a
N atoms,
of the %-system.
References
1) D.S.Jackson, 2)
K.Nakamoto,
3)
G.G.Kleinspehn,
4)
A.J.Durbetaki Society,
5) M. Busch
J.Chem.Soc.
(B),
M.Margoshes
and R.E.Rundle,
J.A.Jung
1964,
E.Bamberger
7)
F.A.Neugebauer,
8)
B.C.Gilbert
148th National
Abstracts
and E .Meussdorffer,
6)
J.Amer.Chem.Soc.
and S.A.Studniarz,
and C.Miles,
Chicago,
19s_S, 785. ----
and W.Pemsel, Tetrahedron
and R.O.C.Norman,
J.org Meeting
.Chemistry, of the American
zz,
6480
32, -_
460 (1967).
Chemical
A-47.
J.prakt.Chem.
22,
Ber.dtsch.chem.Ges., Letters
1968, ====
J.Chem.Soc.
121 (1907). 36,
53,
2129. (B),
1966, ====
86.
62,
85 (19o3).
(1955).