Reactivity of arylazomethylenetriphenylphosphoranes towards electrophiles: reaction with cs2.

oo4&4ozo/a4 53.00 + .a0 Rrgamon Pm8 Ltd.

Temhedron Vol. 40, No. 6, pp. 971 to 976, 1984 Printed in Great Britain.

REACTIVITY

OF ARYLAZOMETHYLENETRIPHENYLPHOSPHORANES

TOWARDS

ELECTROPHILES:

A. ALEMAGNA*

, P. DEL

REACTION

BUTTERO,

S. MAIORANA

Istituto

di Chimica Industriale si e la Stereochimica Via C.Golgi

WITH

CS2.

E. LICANDRO,

and R. TRAVE

dell’Universita’, Centro CNR per di Speciali Sistemi Organici, 19-20133 Milano, Italy.

in UK

(Receiued

la Sinte-

13 October 1983)

proceeds via the direct attack of the elec Abstract - The title reaction trophilic reagent onto the nitrogen atom 3 to the ylidic carbon of the phosphoranes, followed by ring closure to 4-aryl-1, 3,4-thiadiazoline-5thiones, with elimination of PPh 3’

In spite vity

of the very

of the terms

large

amount

stabilized

of literature

by an azo group.

We have been

1,2

rylazomethylenetriphenylphosphoranes

(1)

the azo group

of employing

suggested

the possibility

little

on phosphoranes,

for

is known

investigating

a long time, them

mainly

about the reacti-

the behaviour because

in the synthesis

of the a-

the presence

of

of heterocycles.

:0

-_?!-.$_OC,,,

COOCH3 f---t

ArN = N-C: Pb Our previous tions

stuaies

with double

The results

great ferent

ranes 3-thiac

the ylidic

and with-molecular kind of reactivity

ana lntra reactions

of compounds

of the phosphoranes.

charge

in compounds

and the electrophilic

these

wltn m

reagents,

CS2 had already

of non stabilized reactivity

could

(l),

alkylidene

shown

toward

attack

phosphoranes6.

have led to the synthesis

be delocalized a priori,

an interesting

type

In the case

.

there-

the common

them,

485

only partial-

it interesting,

in principle,

may

reac-

with C=O groups

(1) and were

We thought

can,

reagents

molecular

elecon a

onto dif-

of reactivity

of azophospho-

of 2-aryl-4-alkoxycarbonyl-1.2,

Lazoline-5-thiones.

We wish

now to submit

1) with CS2.

A) Fr.!fluxing CS2.

carbon

(1) an analogous

concernea

of the arylazomethylenephosphoranes

The negative

Among

were

behaviour

the reactivity

of the molecule

positions.

toward

bonds3

with the known

reagents.

portion

C-C

t+) PPh,

0)

compounas

a new and peculiar

t:b investigate

trophilic

ble

and triple

showed

ly in agreement fore,

on tnese

ArN-N-C,

which

B) Refluxing

solutions acted

the results

The reactions

also

solutions

of our research

were

carried

on the reactions

out following

of the arylazomethylenephosphoranes

of phosphoranes

two procedures, (1 a-e)

i.e.

in a very

(1 a-e)

large

excess

as the solvent. in CH3CN

of (1 a-d)

and CS2 in large 971

excess

(about

(Ta-

:

1:lO;

1:17 moles),

of

912

A. hMAGN.4 et al. TABLE 1

N=N-c R

,PPh,

+cs, __+

-y-N=C,

R

'CC!,Me

gcy-I

,

(la- e)

c,lEb,, f

COzMe

;Pb R

N

6

s//\ s

,C-C02Me

(2a-e) Reactant

Reaction

R

Reaction time(h)

Product,

&yield

(la)

H

A B

20 6.5

(2a), 90 II , 70

(lb)

p. CH30

A B

30 6

(2b), 60 I, 8 90

(lc)

p. Cl

A B

30 9

(2c), 70 I, , 75

(Id)

P. NO2

A B

>> 72 28

(2d), 10 I, , QO

(le)

o. C=C-C02Me k

A

72

Reaction procedure,

7

times and results are reported

Instead of the 1,2,3-thiadiazoline-5-thiones

(2e),

90

in Table 1.

both A and B procedures

gave the isomeric

1,3,4-

thiadiazoline-5-thiones was confirmed

(2 a-e) as the only reaction products, The structure of these products 1 by elemental analysis, IR, H NMR, mass spectra, and by comparison with au-

thentic samples prepared from the corresponding In order to check whether the reaction intermediate

formation

arylhydrazonoyl

of our phosphoranes

of nitrile imine and elimination

same substituents as the phosphoranes

however,

with CS2 could take place through the

of PPh33 , the nitrile imines bearing the

(1 a-e) were generated in situ from the hydrazonoyl

des (3 a-e) with Et3N, and reacted with CS2* following tives (4 a-d),

procedure

*

cyclization3.

A and/or

Nloreover,

hali-

B. The Spiro deriva-

(Table 21, were the main reaction products from (3 a-d),

not react with CS2 and gave only the 3,4-dimethoxycarbonylbenzo[f]l, lecular

halides (3 a-e) and xantate7.

2-diazepine

while (3e) did (5) by intra mo-

the 4-p. chlorophenyl-2-methoxycarbonyl-l,3,4-thiadiazoline-5-

To our knowledge, only one egample vative, has yet been reported .

of such reaction,

leading to the formation

of a Spiro deri-

Reactivity of arylazomethylenetriphenylphosphorsnes TABLE 2

NH-N = c

/cl

t&N

+ cs,

973

R

* MeCOr

5

‘co2Me

,S\I N-! &,C-CozMe

+ 2

N -N R

(La-d )

(3a-d) Reaction time(h)

Reaction method

R

Reactant

Products

(3a)

H

B

4

(3b)

p. CH30

A B

32 6

(4b) (4b)-(2b)

(3c)

p. Cl

A

19

(4c)

(3d)

P. NO2

B

3

thione (2~) did not further react with the azophosphorane for 18 h, whereas by reaction

with the hydrazonoyl

tive (4~). It is demonstrated,

therefore,

arylazophosphoranes

70

(4a)

6 32-5

50

21-9

(4d)-(2d)

(1~1, even by refluxing it in CH3CN

halide (3~) and Et3N, it gave the spiroderiva-

that nitrile imines

tion of (1) to give (21, that CS2attacks directly

%Yield

are not the intermediate

in the reac-

the nitrogen atom p -to the ylidic carbon of the

(1) and that the ring closure

follows

with elimination

of PPh 3. (Table 1,

heading). The attack of an electrophilic methylenephosphoranes (1 a-d),

agent onto a site different from the ylidic carbon in the arylazo13 (1) is in agreement with their C NMR spectral data’. In compounds

the chemical

sphoranes, difference

shift of the ylidic carbon ranges from 90 to 99 ppm; in the simpler pho10 stabilized only by an alkoxycarbonyl function, it ranges from 29 to 33 ppm , This

in the chemical

shift shows that the ylidic carbon in the azomethylenephosphoranes

(1) bears less negative charge than in simpler Reactlaon times, are considerably

although only qualitatively accelerated

tion of the phosphoranes

alkoxycarbonyl

determined,

by the presence

of the polar solvent CH3CN*,

with CS2 is favoured by the presence

donors,

whereas it is unfavoured by the presence

groups.

This fact should be consistent

on the reactivity

reactions

and that the reac-

on the aryl moiety of electron

on the same moiety of electron

with the first step of the reaction

onto the N atom) beeing the rate determining Research

phosphoranes.

show that all the described

withdrawing

(electrophilic

attack

one.

of the arylazomethylenephosphoranes

(1) towards other electrophilic

reagents is in progress.

*

In the case of (1 b-d), the solvent effect appears particularly compounds are only slightly soluble in CS2.

significant

also because these

A. I&MAGNA et al.

914

TABLE Analytical

Comp.

3

data of new compounds Required

Found %

Formula

M. p. (Oc) (Cryst. solvent)

C

H

N

C

%

H

N

(le)

1’78 (MeOH)

C31H27N204P

70.79

5.21

5.31

71.26

5.17

5.36

(2a)

120 (EtOH)

C10H8N202S2

47.23

3.21

10.97

47.61

3.17

11.11

(2b)

148 (MeOH)

C11H10N203S2

46.36

3.59

9.85

46.80

3.55

9.93

(2c)

180-l

(C6H6)

c10H7cW202s2

42.42

2.46

9.86

41.88

2.45

9.76

(2d)

180-i

(BUSH)

C10H7N304S2

40.88

2.38

14.31

40.40

2.35

14.14

C14H12N204S2

49.80

3.61

8.25

49.95

3.57

8.33

c~H~C~N~O~

42.36

3.15

16.24

41.94

3.11

16.31

(2e)

121-2 (C H light petro Be&I

(34

215-17

(CH~CN)

(3e)

97-9 (MeOH)

C13H13C1N204

52.64

4.45

9.37

52.70

4.49

9.46

(4a)

149 (EtOH)

C19H16N404S2

53.00

3.77

12.98

53.27

3.73

13.08

(4b)

12 6 (i. PrOH)

c21H20N406s2

51.06

4.14

11.32

51.64

4.10

11.47

(4c)

161-3 (MeOH)

C19H14C12N404S2

46.03

2.78

11.15

45.87

2.82

11.27

(4d)

220 (BUSH)

C19H14N608S2

43.96

2.75

16.09

44.01

2.70

16.22

(5)

150-2

C13H12N204

59.96

4.57

10.68

60.00

4.61

10.77

(CDC13 unless

otherwise

(MeOH)

Spectral

Comp.

V

max

km-‘)

(nujol)

1670,

1630

data of new compounds

‘H N. M. R.

3.72(3H,

s),

3.78(3H,

s),

4.05(3H,

s), 7.25-7.78(5H,m)

5.9(1H, d, J=16 j, 6.8-7.8(20

(le)

1720,

(2a)

1750

(2b)

1745

3.9(3H, s),

s), 7.52(2H,

d, J=9), J=9),

4.02(3H,

s),

(2c)

1745

4.06(3H,

(2d)

1745

4.09(3H,

s), 8.1(2H,d,

(2e)

1740,

1700

3,83(3H,

s),

3.92(3H,

s), 7.32(2H,d,

(3d)

3260,

1705

(3e)

3360, 1630

1730,

(4a)

1740

(4b)

1740,

1710,

4.08(3H,

6.99(2H,d,

s),

7.6(2H, d, J=10)

J=9)

J=16),

8.25(2H,d,

7.35-7.9(5H,m)

J=9),

J=l6),

1l.l2(1H,

s)**

7-7.77(4H,m),

1710

(4c)

1745, 1720

3.9(3H,ss),

1715

4(3H, s),

7.4(2H, d, J=9),

(5)

3285, 1720

3,85&H,

S),

7.93(1H,

s)

spectrum:

m/z 286(M+)

**DMSO ***Mass

8.41(2H,d,

6.45(1H,d,

J=9),

J=lO),

H,m)

7.75(2H, d, J=9)*

3.87(3H, s), 3.98(3H, s), 6,42(1H,d, 7.85(1H, d, J=16), 8.57 (lH, s)

(4d)

*Mass

stated)

spectrum:

m/z 497(M+)

7.3(4H,~?*~ 8.2(2H,

6.75(1H, d, J=8),

d, J=9)

6.90(lH,

s)> 7.06-7.

4(4H,m),

Reactivity of arylazomethylenetriphenylphosphoranes

975

EXPERIMENTAL M.p.

s were

tra were

taken by means

recorded

mical

shifts

given

in Hz.

by Perkin-Elmer

are expressed Mass

60 (Merck, Merck

70-230

377 and Varian (SiMe

was used for

gel 60F-254

and chemicophysical

Starting

from

column

described2b, Reactions

311-A

spec-

respectively.

Che-

Coupling

mass

constants

spectrometer.

T. 1. c. s were

are reported

(3 a-e)

s.

conditions

in Table

Silica

performed

gel on

with two moles

(le)

was pre-

of

by M&kll.

were

prepared

by a known method l?

are

reported

in Table

(3 d,e)

2b.

(3 a-c)

had already

been

3.

(1) with CS

A

The reaction (see times

residue

course

(1 a-e)

was monitored

in Table

was crystallized

from

are given

(eluent:

in the case

and then crystallized

in Table

from

were

refluxed

C6H6-EtOAc

1:l).

At the end of the

underreduced

of (la).

pressure

In the other

the appropriate

in CS2 (25

cases

solvent.

in CH3CN

it was exReaction

1.

times

(1 a-d)

(15 cm3).

complete

and yields

(1.06

The reaction

conversion,

are reported

. 10m3 moles)

course

the work

of arvlchlorohvdrazones

Procedure

and CS2 (1.7

was monitored

up was performed

in Table

(3) with Et-N r)

by t. 1. c.

,lO

-2

moles)

were

re-

(eluent:C6H6-EtOAc

as described

under procedure

A.

1. and CS2

A s (3 b, c) (8.2 6 . 10 -3 moles) and Et3N (9.75 .10W3 moles, 3 in CS2 (75 cm ). The reaction course was monitored by t. 1. c. (eluent:

Arylchlorohydrazone

1.4 cm

refluxed

Et20

ting from

and the

B

After

Reactions

. 10m3 moles)

of CS2 was evaporated

light petroleum,

Arylazomethylenephosphoranes

Reaction

(2.13

by t. 1. c.

1) the excess

with hot light petroleum, and yields

Procedure

(3b),

lohydrazones,

C6H6-EtOAc

9:l

the solutions

were

when starting extracted

CS2 was evaporated

under reduced

derivatives

Reaction

(3e),

are

3.

been describedl’

and reaction

employed

of arvlazomethvlenetriphenvlphosphoranes

reaction

tracted

had already

by diazotization

Arylazomethylenetriphenylphosphmanes

1:l).

standard).

chromatography.

(1 a-d)

under the same

12, Data for

Procedure

fluxed

MAT

data oi new compounds

o. aminobenzaldehyde

Arylchlorohvdrazone

times

spectrometers

as the internal

and N.M.R.

materials

Ph3P=CH-COOMe

cm3).

EM-390

I.R.

plates.

Arylazomethvlenetriphenvlphosphoranes. pared

and are uncorrected.

4 taken with a Varian

were

mesh) silica

apparatus

as &values

spectra

pre-coated

Analytical

of a B&ii

(4 b, c).

reacted

as above

for

times

from

(3~)).

with water

pressure

and dried

and the residue

and yields

are

After

reported

complete over

conversion

Na2S04,

wa- crystallized in Table

3

) were

when starof the ha-

The excess

of

to give the spiro

2.

1 h, gave the 3,4-dimethoxycarbonyl-benzo[fll,2-diazepine

(5) with

a 98 % yield, Procedure

B

_

Arylchlorohydrazones

(3 a,b,d)

1o-3

were

moles,

1.4 cm2)

(8.13

refluxed

. low3

moles),

in CH3CN

(3f

I

CS (8.13 .10 -2 moles) and Et3N (9.75 d rrr. ). The reaction course was monitored

.

A. AUMMNA et al.

976 by t. I.c. (eluent:CHCl3

when starting from (3a), Et20 when starting from (3b), C6H6 when star-

ting from (3dl). The work up was performed and Et3N under reduced pressure, was recovered

by evaporating

by evaporating

the solvent and the excess

taking up the residue in water and extracting

the solvent and crystallizing

ther complex mixture suere obtained,

the residue.

From

of CS2

with CHC13. (4a) (3b) and (3d) ra-

which were separated by column chromatography

CHCl, starting from (3b), C6H6 starting

from (3d)k Reaction

times and yields

(eluent:

are reported

in

TabIe”2. Reaction of 2-methoxycarbonyl-4-p. zonovl chloride

chlorophenyl-1.3,4-thiadiazoline-5-thione

(3~) and Et3_N

To a mixture of (2~) (1.4’0 low3 moles) (2.140 10m3 moles,

0.3

and (3~) (1.4* 10B3 moles)

cm31 was added. After 19 h (complete

the mixture was poured into water (100 cm3). dried,

(2~) with hydra-

was practically

pure (4c), m.p.

The precipitate,

157-161%

in CH3CN (30 cm31 Et3N

conversion:

t. 1. c.: eluent C6H6)

filtered,

washed with water and

Yield 90%.

REFERENCES 1 2a b 3 4

G. Mgrkl,

P. Dalla Croce,

Lett.,

1061, 607.

V. N. Chistokletov P. Del Buttero,

and A. A. Petrov,

E. Licandro

A. Alemagn a, P. Del Buttero,

E. Licandro

A. Alemagna,

E. Licandro,

Comm., 5

Tetrahedron

V. V. Kosovetsev,

P. Del Buttero,

J.Gen. Chem.,

and S. Maiorana,

and S. Maiorana,

1970,

Svnthesis,

40,

1979, 299.

Gazz. Chim.Ital.,

S. Maiorana and C. Guastini,

2116.

1961, ll& 265.

J. Chem. Sot., Chem,

1863, 337.

A. Alemagna,

P.Del

Buttero,

E.Licandro

and S. Maiorana,

J. Chem. Sot.. Chem. Comm.,

1961, 694. J.Bestmann, R.Fusco

R.Engler,

and C. Musante,

R.Huisgen,

R.Grashey,

H.Hartung and K.Roth, Gazz. Chim.Ital., M. Seidel,

S, Bradamante and P. Del Buttero, 10 11 12

G.A.Gray,

J.Am.Chem.Soc.,

Houben-Weyl, R.Fusco

1979, l&

1938, j&

H.Knupfer

and R. Schmidt, &.,

1973, f$5, 7736.

Gazz. Chim.Ital.,

Chemie,

Vol. X/3,

1946, s

28.

147, 665.

work to be published.

Methoden der organischen

and R.Romani,

E.,

419.

p. 538.

1962, m,

169.