Reactions of α-aminoester imines with nitrosobenzene

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).