AMX DAS-M-0608 Bedienungsanleitung PDF herunterladen (Seite 166)

157

11

ABSTRACT

The

synthetic

potential

of

the

cydometdation

reaction

with

a

view

to

the

func-

tionalization

of

aromatic

ortho

positions

and

to

the

formation

of

heterocydes

was

investigated

with

the

aid

of

four

examples

:

(1)

Severd

attempts

to

synthesize

simple

N-

or

S-conteining

heterocydes

start¬

ing

from

N,N-Dimethyl-o-toluidine

(1)

were

not

successful.

N,N-Dimethyl-

o-toluidine

(1)

could

certainly

be

cyclopalladated

to

yield

the

corresponding

complex

4,

which

after

reaction

with carbon

monoxide

in

methanol

gave

a

mixture

of

the

methyl

ester

6

and

the

methyl

ether

7.

But

the

N,N-dimethyla-

ted

ester

6

cannot

be

cydisized.

Therefore,

some

other

derivatives

of

o-tolui-

dine

(2)

were

investigated:

N-neopentylidene-o-toluidine

(9),

N-trichloro-

ethylidene-o-toluidine

(13),

N,N-diacetyl-o-toluidine

(14)

and

N-trimethyl-

silyl-o-toluidine

(17).

However,

palladation

of

these

Compounds

at

the

aro¬

matic

methyl

group

faUed,

as

did

the

oxidative

addition

reaction

of

o-amino-

benzyl

chloride

to

bis(dibenzylideneacetone)pdladium(0).

(2)

AcetanUide

(22)

reacted

with

palladium

acetete

to

give

the

complex

21,

which

was

treated

with

sodium

chloride

and

1,2-bis-p-tolylthio-ethane

(27)

to

afford

the

corresponding

complexes

20

and

28.

Reactions

of

these

complexes

with

the

reagents

mentioned

below

usually

rendered

acetanilide

(22)

as

the

main

product.

In

the

case

where

the

acetato

bridged

complex

21

was

treated

with

ammonium

thiocyanate

or

with

thiocyanogen,

surprisingly

the

2-cyano

acet¬

anilide

(29)

was

formed

with

expulsion

of

sulfur.

On

the

other

hand,

the

monomeric

complex

28

containing

the

S,S-bidentete

ligand

reacted

with

thio¬

cyanogen

to

yield

the

sulfur

containing

heterocycle

31

in

one

case

and

the

2-thiocyanato

acetanilide

(33)

in

another

reaction

under

similar conditions.

An

attempt

to

exchange

the

acetato

Ugand

of

complex

20

with

the bidentate

dithiocarbamate

(in

order

to

monomerize

complex

20

and

to

make

the

Pd-C

bond

more

reactive

towards

insertion

reagents)

led

to

the

symmetrical

biphenyl

24,

a

coupling

product

of

the

acetanilide

ligand.

The

same

product

was

obtained

when

complex

21

was

treated

with

sodium

azide,

whereas

p-toluenesulfone

azide

(35)

did

not

react.

Formation

of

the

acetylamino-benz-

amides

36

and

37

resulted

from

the

reaction

of

complex

20

with

isocyanides.

1 2 ... 161 162 163 164 165 166 167 168

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