FR2614296A1 - NOVEL BISBENZOTRIFLUORIDE DERIVATIVES AND PROCESS FOR THEIR PREPARATION. - Google Patents

Abstract

THE INVENTION RELATES TO NEW BISBENZOTRIFLUORIDE DERIVATIVES, SUCH AS BIS (TRIFLUOROMETHYLPHENYL) ETHANE OR BIS (TRIFLUOROMETHYLPHENYL) ETHYLENE. ACCORDING TO THE INVENTION, TRICHLOROMETHYLBENZOTRIFLUORIDE OR DICHLOROFLUOROMETHYLBENZOTRIFLUORIDE ARE SUBJECTED TO A COUPLING REACTION WITH DEHALOGENATION IN A GAS HYDROGEN ATMOSPHERE; THE REACTION IS CARRIED OUT AT A MODERATELY HIGH TEMPERATURE IN THE PRESENCE OF A PALLADIUM CATALYST; ANOTHER NEW COMPOUND, BIS (TRIFLUOROMETHYLPHENYL) -ACETYLENE IS OBTAINED BY HEATING THE FIRST DERIVATIVE OF BISBENZOTRIFLUORIDE OBTAINED AT A TEMPERATURE ABOVE 50 C IN THE PRESENCE OF A METAL ACTING AS TELALOGENANT,. THE INVENTION IS APPLIED IN PARTICULAR TO THE PREPARATION OF USEFUL DERIVATIVES AS MEDICINAL PRODUCTS, AGRICULTURAL CHEMICALS AND NEW POLYMERS.

Description

The present invention relates to a group of novel derivatives of

  bisbenzotrifluorides which will be useful as materials for drugs, agricultural chemicals and novel polymers as well as processes for their preparation. As far as we know, no literature

  does not indicate the preparation of bisbenzotri-

fluorides.

  The possibility of synthesizing bis (trifluoro-

  methylphenyl) acetylene by the steps of conducting the condensation of trifluoromethylbenzaldehyde into a benzoin form, converting it to a stilbene derivative, adding bromine to it and then carrying out an elimination reaction was considered. However, this process comprises many reactions, each of which is not very simple in industrial practice, and the

  trifluoromethylbenzaldehyde is expensive.

  The present invention provides novel bisbenzotrifluoride derivatives represented by the general formula (1):

CF3 C R CF3 (1)

  o R represents -CC12CC12-, -CCl = CCl- or -CC-.

  2 C2-1-C = C? In fact, the new compounds of the invention are bis (trifluoromethylphenyl) tetrachloroethane, bis (trifluoromethylphenyl) dichloroethylene and bis (trifluoromethylphenyl) acetylene. These compounds will be useful as intermediates for the synthesis of drugs and chemicals for agriculture

  and also for the production of new polymers.

  The present invention is based on the fact that it was first found that one could prepare either bis (trifluoromethylphenyl) tetrachloroethane or bis (trifluoromethylphenyl) dichloroethylene, ie a bisbenzotrifluoride derivative represented by the general formula (1A), by subjecting a trihalomethylbenzotrifluoride represented by the general formula (2) to a coupling reaction with dehalogenation in a hydrogen gas atmosphere, CF3 R'-CF3 (iA) o R 'represents CC12CCl2- or -CCl = CCl-,

CF 2 2

_CF3

Q CC2X (2)

  X is Cl or F, and further that bis (trifluoromethylphenyl) acetylene, i.e. a bisbenzotrifluoride derivative represented by the general formula (1B), could be prepared by heating a compound represented by the general formula ( 1A) at a temperature of not less than 50 C in the presence of a metal which serves as a dehalogenating agent: CF3-Q CC-CF3 (1B) The coupling reaction with dehalogenation to form a compound-of the formula (1A) is carried out using palladium as a catalyst, at an elevated temperature, preferably under a certain pressure and also preferably in the presence of a base. The type of the coupling radical R 'of the reaction product depends on the temperature and pressure conditions. The reaction to convert a compound of formula (1A) to an acetylenic compound of formula (1B) is carried out in an organic solvent, preferably using zinc as dehalogenating metal. As the trihalomethylbenzotrifluoride starting material for preparing a compound of the formula (1A), either

  trichloromethylbenzotrifluoruria or dichlorofluoro-

  Methylbenzotrifluoride is useful, although the former is preferable. The position of the group -CC13 or -CC1 2F relative to the group -CF3 may be one of the positions

o-, m- and p-.

  For the coupling reaction of trihalomethyl-

  benzotrifluoride selected, it is appropriate to use a palladium catalyst such as a palladium on carbon catalyst. The amount of the palladium catalyst is variable over a wide range, for example from 0.01 to

  % by weight (in the form of palladium) of the trihalogen

  methylbenzotrifluoride. Usually, a suitable amount of palladium is between 1 and 10% by weight of the starting compound. The reaction is carried out in an autoclave filled with hydrogen gas maintaining a temperature of not less than 50 ° C for several hours. The hydrogen gas pressure must not be subatmospheric and it is preferable

  to carry out the reaction at a moderately high pressure.

  The pressure of the hydrogen gas and the temperature of the reaction are selectively changed depending on whether the compound

  formula (1A) is bis (trifluoromethyl)

  phenyl) ethane or bis (trifluoromethylphenyl) ethylene.

  In addition, the position of the group -CCl3 or -CC12F relative to the group CF3 must be taken into consideration. Indeed, in the case of the position m, it is necessary to use more severe reaction conditions than in the case of the position p and even more severe conditions are necessary in the case of the position o. It is favorable for the desired coupling reaction, to add a base such as potash or soda, in the reaction system. In general, it is better to use potash in an amount equal to

  2 to 4 times the equivalent of trihalomethylbenzotrifluoride.

  In the case of the synthesis of 1,2-bis (4'-tri-

  fluoromethylphenyl) -1,2,2-tetrachloroethane, it is appropriate to carry out the coupling reaction under a hydrogen gas pressure of 2-4 bar at 50-100 ° C. In

  the case of the synthesis of 1,2-bis (4'-trifluoromethyl)

  phenyl) -1,2-dichloroethylene, it is appropriate to carry out the reaction under a pressure of 3-4 bar at

  -120 C. When preparing 1,2-bis- (3'-trifluoro-

  methylphenyl) -1,1,2,2-tetrachloroethane, bis (3'-trihydro)

  fluoromethylphenyl) dichloroethylene, bis (2'-trifluoro-

  methylphenyl) tetrachloroethane or bis (2'-trifluoro-

  methylphenyl) dichloroethylene, it is favorable for the promotion of the coupling reaction, to further raise the hydrogen gas pressure of about 1-2 bars and the

  reaction temperature of about 10-30 C.

  An acetylenic compound of formula (IB), such as bis (trifluoromethylphenyl) acetylene, can easily be obtained by dechlorination of a compound of formula (IA), namely bis (trifluoromethylphenyl) ethane or bis (trifluoromethylphenyl) ethylene, using a metal such as zinc or magnesium which serves as dehalogenating agent. It is better to use zinc. The amount of the metal must be at least stoichiometric, and the presence of excess metal poses few problems. The dechlorination reaction is carried out in a suitable organic solvent, preferably in acetic anhydride, while continuing to heat to a temperature which

is not less than 50 C.

  The invention will be better illustrated by the following nonlimiting examples. Examples 1 to 5 relate to the synthesis of the compounds of the general formula (1A) and Examples 6 to 8 to compounds

acetylenic compounds of the formula (1B).

Example 1

  A 100 ml stainless steel autoclave was charged with 20 g of p-chloromethylbenzotrifluoride, 300 mg of a palladium-on-charcoal catalyst (5% Pd)

  by weight), 8g of potash and 10 ml of water.

  The atmosphere in the autoclave was replaced by hydrogen gas and the gas pressure was regulated at 3 bar. Then, the mixture in the autoclave was kept heated at 110 ° C. for 4 hours. The reaction product

  was dissolved in dichloromethane and washed with water.

  After recovery of the palladium catalyst, the solution

  was concentrated to obtain 17.3g of 1,2-

  bis (4'-trifluoromethylphenyl) -1,1,2,2-tetrachloroethane.

Example 2

  The reaction of Example 1 was modified solely by the fact that 20 g of mtrichloromethylbenzotrifluoride was used as starting material. The reaction product was treated in the same way as

  Example 1. Thus 12.1 g of 1,2-bis (3'-trihydroxyl) was obtained.

  fluoromethylphenyl) -1,1,2,2-tetrachloroethane.

Example 3

  Of the materials used in Example 1, the

  benzotrifluoride has been replaced by 20g of o-trichloro

  In this case, the hydrogen gas pressure in the autoclave was regulated at 4 bar and the reaction was carried out at 120 ° C. for 6 hours. The reaction product was treated in the same manner as in Example 1. As a result, 8.8 g of 1,2-bis (2'-trifluoromethylphenyl) -1,2-dichloroethylene was obtained.

  (mixture of the cis form and the trans form).

Example 4

  A 30 ml stainless steel autoclave was

  charged with 4 g of m-trichloromethylbenzotrifluoride, from.

  mg of a palladium on carbon catalyst (Pd.5%

  by weight), 1 g of potassium hydroxide and 2 ml of water.

  The atmosphere in the autoclave was replaced with hydrogen gas and the pressure of the gas in the autoclave was regulated to 5 bar. Then, the mixture in the autoclave was kept heated at 130 ° C. for 4 hours. The reaction product was dissolved in dichloromethane and washed with water. After recovery of the catalyst, the solution was concentrated for

  obtain 2.24 g of 1,2 bis (3'-trifluoromethylphenyl) -

  1,2-dichloroethylene. The stereoisomerism of this compound was examined by gas chromatography. The

  ratio of the cis formula to the trans form was 7: 3.

Example 5

  Among the materials used in Example 4, the benzotrifluoride was replaced by 4 g of p-trichloromethylbenzotrifluoride. In this case, the hydrogen pressure was regulated at 3 bar and the reaction was carried out at 1200C for 4 hours. The reaction product was treated in the same way as

  Example 4. As a result, 2.8 g of 1,2-bis (4'-

  trifluoromethylphenyl) -1,2-dichloroethylene. In this compound, the ratio of the cis form to the trans form

  was found to be 2: 1 by gas chromatography.

Example 6

  In a glass reactor 41.2 g was dissolved

  1,2-bis (4'-trifluoromethylphenyl) -1,1,2,2-tetrachlorophenol

  ethane in 316 ml of acetic anhydride and the solution was kept heated at reflux temperature for 24 hours while intermittently adding (10 times) zinc dust to the solution. A total of 60 g of zinc dust was introduced into the reaction system. Then, ether was added to the reaction liquid and the insoluble material was removed by filtration. The filtrate was concentrated to recover the organic material, which was refined by column chromatography on silica gel using hexane as the developing solvent. As a result, we obtained

  23.0 g of 1,2-bis (4'-trifluoromethylphenyl) acetylene.

Example 7

  A solution of 3.7 g of 1,2-bis (3'-trifluoro-

  methylphenyl) -1,1,2,2-tetrachloroethane in 50 ml of acetic anhydride was kept heated at the reflux temperature for 41 hours while intermittently adding (10 times) zinc dust (12 g in total) to the solution. The reaction product was dissolved in ether and refined by column chromatography on silica gel in the same manner as in Example 6. As a result, 1.9 g of 1,2 bis (3 ') was obtained. trifluoromethylphenyl) acetylene.

Example 8.

  A solution of 1.2 g of 1,2-bis (2'-trifluoro-

  methylphenyl) -1,2-dichloroethylene in 20 ml of acetic anhydride was kept heated at reflux temperature for 40 hours while intermittently adding (10 times) zinc dust (3.5 g total), in the solution. The reaction product was dissolved in hexane and refined by column chromatography on silica gel in the same manner as in Example 6. By

  subsequently, 0.8 g of 1,2-bis (2'-trifluoromethyl) was obtained.

  phenyl) acetylene. Tables 1 and 2 show the results of the analysis of the compounds obtained in the examples above.

26 1 4296

Table 1.

  NMR Spectrum Point Compound (in CDCl3 standard CFC13 melting mass) (m / e) c (ppm) Ex. I: v. 'CC..z F? 63, 43421 (-Cl-) 308: -09 Cl C: CF

C'_ C F

  C F Ex. 2 63,4 227 16 C1 Cl Cr Ex. A 60.92 384 (C ') 12-163

- ^ CF-

Ex. '', 384 (H) Cr-CFr

__

  Ex.4 e- '6: 4 43-49 Es. F =, Cr 63, s 384L (a 2 f8-1: 9 ci

? - 'F%

-X. 5 ',. F. / 63 48 384 (M <) 3: 8-39

Cl C1

26 1 4296

TABLE 2.

  19F-NMR Spectrum Point Compound (in CDCl3 standard mass (m / e) CFC13 melting) (cM (ppm) Ex. 6 CF -, - r3 63. 43 314 (M) 10 08

EX. 7 /, -, - ,, F 6 ^, 48 31.L (Y.) 88

CF, CF.

  Ex.

7 C 4 8 314 ('as CF., Ex. 8.9 314 (2) 68- & 9 I1

Claims (13)

  1. Compound characterized in that it is represented by the general formula (1): CF3 Q R a x-- CF .. (1)   R represents -CC12CC12-, CCl = CCI or -C = -C-.   2. Process for preparing a compound represented by the general formula (! A): CF3 R 'CF3 (1A)   R 'represents -CC12CC12- or -CCI = CCI-, characterized in   what it consists in submitting a trihalomethylbenzotri-   fluoride represented by the general formula (2) in a coupling reaction with dehalogenation in a hydrogen gas atmosphere: CF3 I r 4 - CCl2X (2) at X is Cl or F. 3. Method according to claim 2, characterized in that the reaction is carried out in   presence of a palladium catalyst.   4. Process according to claim 3, characterized in that the palladium catalyst comprises coal as a support.   5. Method according to claim 3, characterized in that the reaction is carried out at a   temperature not lower than 50 C.   6. Process according to claim 5, characterized in that the hydrogen gas atmosphere is   at pressure above atmospheric pressure.   7. Process according to Claim 5, characterized in that the reaction is carried out in presence of a base.   8. Method according to claim 7, characterized in that the base is chosen from the group consisting of potash and soda.   9. Process according to claim 2, characterized in that the trihalomethylbenzotrifluoride   is selected from the group consisting of o-trichloro   methylbenzotrifluoride, m-trichloromethylbenzotrifluoride   and p-trichloromethylbenzotrifluoride.   A process for preparing a compound represented by the general formula (1B), CF3 (C-C QCF3 (1B)   characterized in that it comprises heating a compound represented by the general formula (1A) to a temperature of not less than 50 C in the presence of a metal which serves as dehalogenating agent: C F3 C- R 'CF3 (1A) 26 I 4296   R 'represents -CC1 2CCl2- or -CCl = CCl-.   2 2 11. Process according to claim 10, characterized in that the metal is chosen from the group consisting of zinc and magnesium.   12. The method of claim 10, characterized in that the compound represented by the general formula (1A) is heated in an organic solvent. 13. The method of claim 12, characterized in that the solvent is acetic anhydride.