CATALYTIC PHOSPHORYLATION OF PENTAFLUOROPHENOL

WITH PHOSPHORIC ACID CHLORIDES

M. I. Kabachnik, L. S. Zakharov, I. Yu. Kudryavtsev, A. P. Kharchenko, G. P. Tataurov, and L. I. Korobeinikova

UDC 542.97:547.1'118

The known methods for the preparation of pentafluorophenyl phosphates are the phosphoryl- ation of pentafluorophenol (PFP) with chlorophosphates in the presence of pyridine [i] or with the corresponding imidazolides [2], and also the reaction of potassium pentafluorophen- oxide with POF2Br [3]. Without an HCI acceptor the reaction of PFP with POCI3 requires long refluxing [4, 5]. At the same time, since the phosphorylation of ordinary phenols using chlorophosphates is catalyzed by a number of metal salts [6, 7], it seemed practical to also use this method for the synthesis of pentafluorophenyl phosphates.

We made a detailed study of the phosphorylation of PFP with POCI3 (Table i), and with aryl and polyfluoroalkyl chlorophosphates (Table 2), and established that the process is catalyzed by certain metal salts [8]. The reaction was run by heating a mixture of PFP, the appropriate acid chloride, and catalyst (0.5-21 h at I00-200~ depending on the type of catalyst and the structure of the desired compound). As the catalyst under the selected experimental conditions it is possible to use metal salts with an enthalpy equivalent to that for the formation of metal fluorides from the corresponding chlorides (AH), or else smaller or at most equal to the corresponding value for Mg (56 kcal/mole), which is the maximum AH value for the studied catalysts, where the exchange of F in a perfluoroaromatic nucleus by CI fails to occur when treatment is with metal chlorides, i.e., practically all of the mem- bers of the major subgroups of Groups I and II of the periodic system. LiCI proved to be the most active catalyst. For preparative purposes we also successfully used KCI, CaCI2, NaCI, BaCI2, and metallic Mg, which during reaction dissolved completely, apparently being converted to MgCI2.

The amount of catalyst usually ranged from 0.i to 5 mole % when based on the PFP. When preparing the full pentafluorophenyl phosphates it proved expedient to use close to equiva- lent ratios of the starting reactants. In the case of pentafluorophenyl dichlorophosphate (II) we used a fivefold excess of POCI3. When preparing the monochlorophosphates the equiva- lent ratio of PFP to the acid chloride was predominantly 1:1.8-4.0. The yields of the desired compounds depend on their structure and are 88-94% in the case of the full phosphates, and 50-60% in the case of the pentafluorophenyl chlorophosphates. When preparing the di(penta- fluorophenyl) chlorophosphate it is also possible to isolate both the neutral phosphate (I) and the dichlorophosphate (II), in which connection the total yield reaches 92%.

With our method we synthesized a number of phosphates that lack chlorine in the aro- matic rings (Table 3). Even in the case of the full phosphates, which require the most drastic phosphorylation conditions, replacement of the fluorine by chlorine is not observed. The fact that the synthesized chlorophosphates can be converted to neutral phosphates that are devoid of chlorine serves as evidence that the exchange products of fluorine by chlorine are absent in the synthesized compounds. Thus, the catalytic phosphorylation of l,l-dihy- droperfluorobutanol (IX) with dichlorophosphate (II) leads to the formation of the pure penta- fiuorophenyl di(l,l-dihydroperfluorobutyl) phosphate (VII) in 88% yield. The reaction of dichlorophosphate (II) with n-butanol (X) in the presence of a tertiary amine also gave a pentafluorophenyl dibutyl phosphate (VIII) that was completely devoid of chlorine,

EXPERIMENTAL

The constants of the obtained compounds and their analyses are given in Table 3.

Institute of Heteroorganic Compounds, Academy of Sciences of the USSR, Moscow. Trans- lated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 896-900, April, 1979. Original article submitted June 8, 1978.

840 0568-5230/79/2804- 0840507.50 �9 1979 Plenum Publishing Corporation

TABLE i. with POCI3

Com- pound n

(I) a

(H)I t

( l id 2

Catalytic Phosphorylation of Pentafluorophenol

catalyst nC6FsOH +POCI3 2nI-ICi * (CoFsO)nP(O)Cla-n

(!)--(III)

c ata lyst

LiC1 CaCh

KCl CaCl2

LiCt

[ PPP @OC13: leatalyst m o l , Fatio

3 : t : 0 3 : i : 0 , 0 2 3 : i :0,02

i 5 : 0 i 5 : 0,05 1 5 : 0,05 i 5 : 0,05

2 : t,25 : 0,02

Reaction t im e , h

49 *,'~ i2 2i

72 $ i 4 3

!,2

T,. ~ ~n

i00-220 90 i00-220 89 100-220 88

i i 8 - i i 9 i 73 i 06 -H3 I 54 108-i13 60 t06-t!3 I 59 I00-s I 5i

+3o% (I) +i i% (II)

�9 of . [4]. +The data given in [9] that reaction is complete in 14 h at 70-190 ~ axe apparently ex- plained by the fact that the process is catalyzed by traces of metal salts, which are pos- sibly uresent in the system ~ i d ~ as natural impurit i~ or due to dissoDing of the glass, as was observed in a number of cases during the phosphorylation of phenols was POCls [7].

~Cf. [5].

P h o s P h o r y l a t i o n o f P e n t a f l u o r o p h e n o l w i t h POC13. A m i x t u r e o f 1 8 . 4 g ( 0 . 1 m o l e ) o f PFP,* POC!~, and catalyst was heated until the HCI evolution ceased. Vacuum distillation gave pentafluorophenyl phosphates (I)-(III). The mole ratios of the reactants, the reaction conditions, and the yields are given in Table i.

Phosphorylation of Pentafluorophenol with Aryl and Polyfluoroalky! Phosphates, A mix- ture of 9.2 g (0.05 mole) of PFP, the appropriate chlorophosphate, and catalyst was heated until the HCI evolution ceased. Vacuum distillation gave pentafluorophenyl phosphates (IV)- (VII). The mole ratios of the reactants, the reaction conditions, and the yields are given in Table 2.

Pentafluorophenyl Di(l,l-dihydroperfluorobutyl) Phosphate (VII).t A mixture of 13.6 g (0.045 mole) of dichlorophosphate (II), 20.0 g (0.I mole) of alcohol (IX)) and 0.085 g (0.002 mole) of LiCI was heated for 40 min at 160 ~ . Vacuum distillation gave 24.8 g (88%) of phos- phate (VII).

Pentafluorophenyl Dibutyl Phosphate (VIII): With stirring, to 5.9 g (0.08 mole) of alcohol (X) and 8.1 g (0.08 mole) of Et3N in 40 ml of abs. benzene was added in drops at

20 a solution of 12.0 g (0.04 mole) of dichlorophosphate (II) in 20 ml of abs. benzene and the mixture was let stand overnight. The precipitate was filtered, while the solution

TABLE 2. Catalytic Phosphorylation of Pentafluoro- phenol with Aryl- and Polyfluoroalkyl Chlorophosphates

catalyst C6FsOH + (HO)nP(O)Cl~-n --HCl '~ (RO)nP(O)(OC6Fs)Ct2-n

( iv ) - (Vl I )

C o m -

pound

(IV) (V)

(VI) (VII)

R Cat - alyst

C~H5 NaC1 C~H5 Mg CFsCH~ BaCh C~TCH~ LiCI

catalyst mole ratio

t 2 : 0,02 2 I i : 0,02 1 i 2 : 0,00i 2,5 i i : 0~02 0,7

T., ~

i90-220 130-2t0 i50-169 t05-t95

Yield,

62 94 57 92

*In the preparation of phosphate (I) the charge of PFP was 27.6 g (0.15 mole). fAlse see the described phosphorylation of PFP with polyfluoroalkyl chlorophosphates (Table 2).

841

TABLE 3.

Corn

- po

und (D

(II)

OU

)

(iV

)

(V)

(VI)

(vz!

)

(vm

)

Properties

of Pentafluorophenyl

i

Form

ula

(C+H

+O).+

~O [~

]

C~F~

OP (O) C12 [5]

(C6F50) ~P (O) CI [5]

(CsF+O) P (O) (OCeHs) CI

(C6F

~O) P

(0) (OCoHa) ~

[l]

(C~F

sO) P

(O) (

OC

H2C

Fa) C

1

(C+F

sO) P

(O) (

OC

HzC

~FO

2

(C,F

,O) P

(o) (

OC~H

~) ~ [

5!

b R ~

(L

mm

of

rig

)

t38-

t39

(t)

rap,

47.

5-49

.0)

(fro

m h

exan

r

io~

(14)

8s-

9o

(i)

95-9

0 (t

)

t52-

153

(1)

m L

63-

85

(fro

m h

exan

ei

117-

1t8

(i3)

84-8

5 (1

)

t28-

t29

(t)

Phosphates

20

d20

~D

1,45

26

t,772

2

1,45

09

t,800

6

i,492

5 1,

5741

1,40

70

t,728

3

,t,35

37

t,758

7

t,430

0 1,

2881

c

++5,..__

+.~

36,2

7

24,1

4 23

,95

32,0

9 32

,13

jo,2

2 40

,t9

5Z,~

L 5t

,94

26,2

3 26

,36

2__6

,71

26,7

7

44.6

9

Foun

d tc

alcu

late

c a/~

H

F C

!

- 48

,12

[ ,-

47

,8t

I

31,t2

23

,9

42,4

2 I

8,,1

, - �9 ,23

26,2

9 [

9,9~

L,4--o

-~6

,~0-

i -9,

s~ ~8

7 2t

,99

I -

,.,42

~-

,s~

:

1,45

41,8

5 9,7

~ 1,5

5 4t

,70

__~,7t

57,7~

},6

4 57

,47

- __

i,s3

25,m

1,8

2 25

,25

-

p 5,43

__

+ 5,20

10,2

8 i0

,29

6,88

6,

9i

~,4!

8,

64

7,6i

7,

44

8,47

8,

50

4,87

4,

93 -

8,23

I Em

piri

cal

form

ula

CisF

i~O

~P

2~CI

2FsO

zP

Ct2C

1FIo

O3P

:::::?Y

o?/

CsH

zC1F

sO3P

CI~H

~Fig

O~P

C~t

t18F

sO~p

was washed with water (5 x I0 ml) and dried over MgS04. Distillation gave 13 g (87%) of phosphate (VIII).

CONCLUSIONS

A new method was developed for the preparation of pentafluorophenyl phosphates, which consists in the catalytic phosphorylation of pentafluorophenol with POCI3, or with aryl and polyfluoroalkyl phosphates, in the presence of the salts of the metals of Groups I and II of the periodic system.

LITERATURE CITED

i. A.V. Podol'skii and M. A. Bulatov, Zh. Obshch. Khim., 46, 531 (1976). 2. E.V. Degterev and L. N. Nikolenko, Zh. Obshch. Khim., 40, 2262 (1970). 3. E.R. Falardeau and D. D. Desmarteau, J. Fluor. Chem., ~, 185 (1976). 4. C.A. Seil, R. H. Boschan, and J. P. Holder, U. S. Patent 3,341,631; C. A., 68, 95520k

(1968). 5. R.H. Boschan and J. P. Holder, U. S. Patent 3,341,630; C. A., 68, 77961a (1968). 6. E. Tschunkur and E. Kniepen, German Patent 367,954; Chem. Zentr., !923II, 916, 7. M. Ya. Kraft and V. V. Katyshkina, Dokl. Akad. Nauk SSSR, 86, 725 (1952). 8. M.I. Kabachnik, L. S. Zakharov, I. Yu. Kudryavtsev, A. P. Kharchenko, G. P. Tataurov,

and L. I. Korobeinikova, Author Application No. 2,506,565/23--04, dated July Ii, 1977, with a favorable decision dated Jan. 23, 1978.

9. I.L. Knunyants and G. G. Yakobson (editors), Syntheses of Organic Fluorine Compounds [in Russian], Khimiya (1977), p. 217.

CHROMIUM AND IRON COMPLEXES WITH HETEROCYCLIC LIGANDS

N. E. Kolobova and L. V. Goncharenko UDC 542.957:541.49:546.765.546.725:547.514.72

Heterocyclic chromium tricarbonyl ~ complexes are formed with much greater difficulty than the isosteric arenechromium tricarbonyls. In condensed heterocycles [I, 2], and also in the 2- and 3-phenylthiophenes [3], the chromium exhibits the ~ type of coordination only with the benzene ring. When the heterocycle is condensed with Cr(CO) s the thiophenechromium tricarbonyl ~ complexes are obtained in low yield [3-5]. A higher yield of the thiophene- chromium tricarbonyls is obtained by using chromium complexes with p-donor ligands, like, for example, acetonitrile [6], y-picoline [7], or pyridine [8].

The insertion of electron-donor substituents into an aromatic ring raises the electron density of the latter and facilitates the formation of ~ complexes with Group VI metal [7, 9]. It seemed of interest to ascertain the effect of such a strong electron-donor substituent as CpFe(CO)2 [9] on the ability of the thiophene ring to form complexes with Cr.

By condensing Cr(CO)6 with the heterocyclic cyclopentadienyliron dicarbonyl ~ derivatives (I) and (II) [i0] we respectively obtained compounds (III) and (IV) in relatively high yield, in which compounds the heterocycle is linked by a ~ bond to the Fe atom and exhibits the

type of coordination with the Cr atom.

J~ J]--Fe(CO)2Cp S

(I)

0 (II)

(CO)3Cr--~---] Fe(C 0

Cr(Co)2:_/ (m)

._> , (CO)3Cr-~o~-'-Fe(CO)2C p (IV)

Institute of Heteroorganic Compounds, Academy of Sciences of the USSR, Moscow. Trans- lated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 900-902, April, 1979. Original article submitted June 29, 1978.

0568-5230/79/2804-0843507.50 �9 1979 Plenum Publishing Corporation 843