Tetrahedron Letters,Vol.30,No.l9,pp Printed in Great Britain
REACTIONS Hernan
OF
Rodriguez
0040-4039/89 $3.00 + .OO Pergamon Press plc
2477-2480,1989
o(-AMINOESTER C. a*, Amelia
IMINES MBrquez
WITH
NITROSOBENZENE
V.a and Claudio
A. Chuaquih
a: Departamento de Quimica Organica: Facultad de Ciencias Qulmicasy Farmaceuticas. Universidad de Chile. Casilla 233 Santiago, Chile b: Radiation Applications Research Establishment.
Research Pinawa,
Branch. Atomic Energy of Canada Manitoba, Canada, ROE 1LO
ABSTRACT: Arylidene imines ofti-aminoesters react with nitrosobenzene at room temperature yielding a diarylnitrone and a Z-diimine.Adecuatemechanistic scheme is postulated to account for the products formed. Imines with
the
of
d-aminoester
corresponding
The formation captured
in good
from
of different 2b,5-7
yields
The nitroso come
group
the prototropic
oxadiazolin-3-carboxylic which
nes,
cannot
oxadiazetidines This
as shown
in
tautomeric
in Scheme
equilibrium
I.
salts
in a number
cycloadduct
in solution 2,
of the 1,3-dipole is catalized by Lewis and Brtinsted acids2, 4 . Both the dipole and the aza-ally1 anion have been
and metallic
bases3
1 exist
azomethin-ylid'
forming
in each
case
is a good
dipolarophile
migration
in A*-oxazolin-S-ones,
acids
form
ways,
the corresponding
. towards
regiospecifically8.
1,3-dipoles,
react
via 2 t 2 cycloaddition
with
Also,
azomethineylids yielding
$-
that 1, 2,4-
methylene-N-phenylimi
nitrosobenzene 9 .
to yield
1,2,4 -
reaction
reports reactions of imines: -la: N-benzylydene-a!-phenylglylb: N-p-methoxybenzylydene-&phenylglycine ethyl ester and Ic: N-methoxybenzylydene-o(-p-methylphenylglycine methyl ester with nitroso and p-methylnitrosobenzene in acetic acid at room temperature. In each case, comtine
ethyl
pound
paper
ester;
2 and a nitrone In a first
with
reaction,
nitrosobenzene
The
reaction
was
The
resulting
with
MgS04
from
petroleum
4 were
(2 mM)
then
solution
imine k
(2 mM)
at 25"C.,
stopped was
and evaporated ether
obtained.
until
by adding
extracted
40-60
and then
water
with
to dryness.
in 3 ml of acetic a colour
from
and then
ether.
The
change
aqueous NaOH
The ethereal
ethereal residue
carbon
acid
occurred
was
tetrachloride.
was
reacted
(10 min.). until
extract
pH 5.
was dried
crystallysed The product,
C-
4a was obtained in 41% yield, mp=lll"C.(lit. 'O=112V.); properties correspond to those of the product of the reaction
phenyl-N-phenylnitrone the
spectroscopic
between
N-phenylhydroxylamine
this
reaction
yields
with
the following
a product
and benzaldehyde". isolated
characteristics:
as white
mp=164-5OC. 2477
In addition crystals
from
to the nitrone, petroleum
and a Rf in di-n-butylether
ether, of
2478
0.19;
elemental
its
required
analysis
9.05(s,
broad,
1.30(t,
J=7
3175, -1
cm
for IH);
Hz,
3075,
The
1751,
and
then
dant
gas
evolution.
(C:70.11;
heated
with This
'H-NMR
with signal
the
linear added, for for
a
of
the
signal
fits
structure
The
that
the
The of
aromatic
signals
vations
correspond
imine
between of
the
with
three
well
IH as
then,
another in
each
a complex
the
and
where
IR
of
with
chemical
was shifts
a chemical follow: the
and a of
show
identical
methyl
protons. with
R2
N=O
+
HN=C’ N:c=o
Ric’
I
9
C 02R3
Reaction NQ
Imine
k'
R2
Ph
Ph
Et
Ph
Ph
Et
Ph
1
la
2
lb
p-MeO-Ph
3
lb
p-MeO-Ph
4
1, -
p-MeO-Ph
SCHEME
1:
Ph p-Me-Ph
Summary
of
R3 _
Et Me
reactions
R4*nitroso derivative
p-Me-Ph Ph
for
slopes
coordinates
C,R2
show
group
II R’_ ,I$
signal
both
small
C02R3
This -3a
cEu+3I Slope
(2H)
are
A4
a
are
the
large
signal
ethoxyl
three +3 Eu
is
displacement
there
There
shift
there
by
corresponding
[EI_I+~] increases.
‘C02R3
It
abu!
confirmed
R2
+
cm-': -1
ethanolic
RcC=N-C/H A
2H);
(KBr)
together
nitrogens.
1
Hz,
kmax=18204dm3mole
solution
assignment
aromatic
while
signals;
protons
with
(NH);
nm
the
(CDC13)ppm:
J=7
D20.
produced
the
as
a
well
-3a cd-imino-N-(1-ethoxycarbo
of
differ
protons
aromatic
as
displacement
well
methylene
was
The
Eu(fod)3.
lines
for as
in
structural
displaced
these
protons,
one
of are
integrates
slopes. than
amounts
4_33(q,
with
h,,x=267
hours acid
compound
product
slopes
aromatic
moderate
two
the
relationships where
two
slopes
increasing
two
fits 'H-NMR
N:9.09).
exchange
benzoic
nylbenzylidene)-phenylacetamide].
to
ppm
which
8H);
(CH2C12)
for
HCl,
H:5.23;
9.05
UV-VIS
1608.
acidified
at
N:9.17
7.97-7.23(m,
2H);
signal
was
H:5.23;
C:70.24;
C,8H,6N203
compound
NaOH
was
8.65-8_38(m,
3H).
1773,
When this
.
analysis
at
two obser the
2479
In a second equivalents
After
of nitrosobenzene.
C-p-methoxyphenyl-N-phenylnitrone
reaction
4c also
5,
this
of
reaction
also
produced
imine -lb was reacted with (C-p-methoxyphenyl-N-p-methylphenylnitrone)'z
In a third ne13 where
11 imine -lb was reacted IO minutes the reaction yielded
one equivalent
reaction,
the
reaction,
produced
with 43%
two of
11% of 3a.
p-methylnitrosobenze was produced,
this
3a. -
In a fourth were
reaction between imine -lc and nitrosobenzene the products 4b and the compound 3b. The latter product has the following char white crystals from petroleum ether 40-60; mp=176-8OC.; elemental
nitrone
acteristics: analysis:
C:71.11;
'H-NMR
(Ccl41
7.53(d,
Jd=8
IR (KBr)
ppm:
(C,9H,8N203
broad.
IH) exchange
of the
titution
imine would
bond, take
4H);
1754(C=O);
show that
it can be seen
tituted
7.40-6_97(m,
3226(NH);
results
C-substituent Also,
N:8.73
lO.l(s,
Hz, 2H);
cm-':
Our
Hz5.76;
imine
the
with
3.73(s,
C:70.79;
020;
3H);
2.43(s,
which
Jd=8
3H);
in the nitrone
N-substituent
comes
from
that 3a and 3b must have a Z-geometry because with an E-geometry an internal place,
H:5.63;
8_47(d,
2.33(s,
would
yield
comes
from
the
N-R4 4,
4 -
1
N=O
F”
R4’
R+=o 6 -
O/R3
/R2
NH II
HN=C
2
’ c=o
N' 6 -
&C02R3 postulated
that
yields
subs-
as a product.
+
+
the
trisubs-
nucleophilic
a di-iminoquinone
7
II: Mechanism
3H).
nitrosobenzene.
around
R'-CH=
SCHEME
N38.69).
Hz, 2H);
1613(C=N).
the C-substituent
while
requires
the observed
products
2480
Scheme dition
II shows
of tautomer
followed
by reverse
ne 2 and nitrone nucleophilic
that
the
reaction
may
-2 and the nitrosoderivative 1,3-dipolar cycloaddition
4 directly14.
substitution
Further
the
consist
in a concerted
to yield
cycload-
an oxadiazolidine
in a different
imine 2 yields
sense
the
to give
product
2 im&
3 via an
reaction.
ACKNOWLEDGEMENT: Financial SuppOrt for this research from the DepartamentO Tecnico de Investigacidn, U. de Chile (Project Q-2312-8824) is gratefully acknowledge. REFERENCES
AND
NOTES
1. R. Grigg, Chem. Sot. Rev. 16, 89-121 (1987). 2. (a) R. Grigg and H. 9. Nimal Gunaratne, Chem. Comm. 384-386 (1982). (b) R. Grigg, H. Q. Nimal Gunaratne, V. Sridharan, Tetrahedron 43, 5887-5898 (1987). 3. M. Joucla and J. Hamelin, Tetrahedron Letters 32, 2885-2888 (1978). 4. D. A. Barr, R. Grigg, H. Q. Nimal Gunaratne, J.
Kemp, P. McMeekin, V. Sridharan, Tetrahedron
44, 557-570 (1988). 5. (a)
R. Grigg,
J.
Kemp, G. Sheldrick, J. Trotter, Chem. Comm. 109-111 (1978).
(b) K. Amornraksa, R. Grigg, H. 4. Nimal Gunaratne, J. Kemp, V. Sridharan, J. Chem. Sot. Perkin Transac. I, 2285-2296 (1987) and ref. therein. (c) 0. Tsuge, S. Kanemasa, M. Ohe, K. Yorozu, S. Takenake, K. Ueno, Bull. Chem. Sot. Japan 60, 4067-4078 (1987). 6. J. Yaozhong, Z. Changyou, W. Shengde, Synth. Comm. -17, 33-38 (1987). 7. R. Grigg and J. Kemp, Chem. Comm. 125-126 (1977). 8. (a) H. Rodriguez, H. Pavet, A. Marquez, P. Navarrete, Tetrahedron -39, 23-27 (1983). (b) H. Pavez, A. Mdrquez, P. Navarrete, S. Tzichinovsky, H. Rodriguez, Tetrahedron _' 43 2223-2228 (1987). 9. C. K. Ingold, J. Chem. Sot. 3,
87-102 (1924).
10. S. R. Sandler, W. Karo in "Organic Functional Group Preparation". Acad. Press. N.Y. (1972 Vol. III, pp 301-320. 11. Imines &,
lb and lc were obtained according to the method of Clark et al. (J. C. Clark,
G. H. Phillips, M.R.
Steer, J. Chem. Sot. Perkin I, 475 (1976)).
12. Nitrones: 4b mp=ll8eC. 'H-NMR (CC14) ppm: 8.36(d, Jd=9 Hz, 2H); 7.90-7.63(m, with a sing1et at 7.82, 3H); 7.53-7.23(m, 3H); 6.88(d, Jd=9 Hz, 2H); 3.87(s, 3H).
IR (KBr) cm-': 1613
(C=N), 1470, 1408, 1266(N+O), 1067, 1029, 892, 778, 758 and 693 (J. Hammer and M. Macaluso, Chem. Rev. 64, 473-495 (1964). 4c: -
mp=130pC.
'H-NMR (CC14) ppm: 8.4(d, Jdy8 Hz, 2H);7.78(d,Jd=8 Hz, 2H); 7.3(d, Jd=8 Hz,
2H); 3.9(s, 3H); 2.45(s, 3H).
IR (KBr) cm":
1605(C=N); 1256(N;O).
13. p-Methylnitrosobenzenewas prepared according to the method of Ingold’,
luidin
with K2S208
wh ch oxidises p-to
and H2S04 at 0-5°C.
14. G. Bianchi, C. de Micheli and R. Gandolfi, Angew. Chem. Int. Ed. Engl. 2,
(Received
in
USA 31 January
1989)
721-738 (1979).