JPH05310615A - Production of perfluoroalkyl-substituted benzene derivative - Google Patents

Abstract

PURPOSE:To produce a perfluoroalkyl-substituted benzene derivative useful as a compounding component of a liquid crystal composition for display element, etc., by using a simple process compared with conventional process and to enable the production of a long-chain derivative which is difficult to be produced by conventional process. CONSTITUTION:A perfluoroalkylbenzene derivative of formula II can easily be produced by reacting a benzene derivative of formula I (X is I or Br; R is H, alkyl, cycloalkyl or aralkyl) with a perfluoroalkane of the formula CmH2m+1 Y (Y is I or Br; m is integer of 1-18) in the presence of a copper catalyst. The process enables the production of a long-chain perfluoroalkyl-substituted benzene derivative which is difficult to produce by conventional process. The above reaction can be carried out at <=200 deg.C or thereabout, preferably at 100-140 deg.C in a polar solvent such as N-methylpyrrolidone, dimethyl sulfoxide or HMPA. The copper catalyst may be Raney copper, Ulmann copper or Urushibara copper, however, copper powder for conventional reaction use may be used as it is as the catalyst.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel method for producing a perfluoroalkyl-substituted benzene derivative useful as a compounding component of a liquid crystal composition used for display devices and the like.

[0002]

2. Description of the Related Art Among benzene derivatives containing a fluorine atom, a benzene compound having a trifluoromethyl group introduced therein is industrially used, and attention is paid to its good stability such as light resistance. In addition, the long-chain perfluoroalkyl group-introduced benzene derivative is at the beginning of its development.
Attention is paid to the influence of the dielectric properties or elastic properties of CF ₂ -bonding on the liquid crystal material.

These perfluoroalkyl-substituted benzene derivatives have hitherto been limited in their industrial application, and therefore a general industrially practical production method has not been established. That is, various reactions in the basic research stage for synthesizing a perfluoroalkyl-substituted benzene derivative are described in various publicly known literatures and books, but the applicable range of these reactions is not clear at this stage. Instead, the actual situation is that individual compound groups are actually verified and synthesized.

More specifically, in the initial stage, the fluorination reaction itself, which introduces a fluorine atom into an organic compound, is the subject of research and development, and since handling of highly corrosive hydrogen fluoride is required, the material of the reaction vessel is included. The industrial manufacturing method was a major issue in the development. Then, recently, various methods for synthesizing a fluorine derivative utilizing a so-called building block, which should be called a component for synthesis having a fluorinated structural portion and a reactive portion, have been proposed. However, these reactions are significantly different from the reactions in conventional compounds containing no fluorine, and it is difficult to analogize their applicable range. Therefore, it is necessary to actually verify each compound group. The current situation.

Among the perfluoroalkyl-substituted benzene derivatives aimed at by the present invention, for trifluorobenzenes, a method of substituting the corresponding trichlorobenzenes with fluorine has been known to be industrially applicable. Further, as the perfluoroethyl-substituted benzene derivative, the method described in Tokuhyo 1-503145, that is, a compound having a bromine atom is used, which is reacted with butyllithium and then reacted with trifluoroacetate to give trifluoroacetophenone. The following route is known in which a derivative is used, and then diethylaminosulfur trifluoride is reacted for a long time.

[0006]

[Chemical 3]

[0007]

However, this method is not industrially practical because it requires a two-step reaction and involves a process that requires a long time, and a long-chain perfluoroalkyl-substituted benzene derivative is synthesized. However, it had a problem that it was difficult to apply. An object of the present invention is to provide a production method which is free from these problems and which is also suitable for the synthesis of long-chain perfluoroalkyl-substituted benzene derivatives.

[0008]

The object of the present invention is to provide a benzene derivative represented by the general formula (1) according to claim 1 with the general formula CmF _{2m + 1} Y (wherein Y is an iodine atom or bromine). Atom, m represents 1 to 18) by reacting a perfluoroalkane represented by the formula (1) to (18) in the presence of a copper catalyst,
To be achieved.

The present invention will be described in more detail below. R in the general formula (1) of the present invention is a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group, an alkyl group such as a decyl group, a cyclohexyl group, a 4-trans-butylcyclohexyl group. , A cycloalkyl group which may have a substituent such as 4-trans-hexylcyclohexyl group, an ethoxymethyl group, an alkoxyalkyl group such as butoxyethyl group, a benzyl group, a phenethyl group, a chlorophenylethyl group, a fluorophenyl group Examples thereof include halogen-substituted aralkyl groups such as ethyl group, alkyl-substituted aralkyl groups such as ethylphenylethyl group and butylphenylethyl group, and aralkyl groups such as alkoxy-substituted aralkyl group such as ethoxyphenylethyl group and pentoxyphenylethyl group.

Examples of X include iodine atom and bromine atom. In the case of this reaction, even if it is a bromine atom, the desired product can be obtained in a good yield. Examples of Y include an iodine atom and a bromine atom. Generally, in the case of an iodine atom, the reaction can be smoothly performed. The reaction can be carried out in a polar solvent such as N-methylpyrrolidone, dimethylsulfoxide or HMPA at a temperature of generally 200 ° C. or lower, but preferably 100 to 140 ° C.

The reaction can be carried out smoothly by using a pressure vessel such as an autoclave when the boiling point of the perfluoroalkane is 100 ° C. or lower. The copper catalyst is
In addition to Raney copper, Ullmann copper, Urushibara copper, those that have been precipitated immediately by the precipitation method or those that have undergone activation treatment such as acid treatment may be used, but copper powder for normal reaction is used as it is. You may use it.

[0012]

INDUSTRIAL APPLICABILITY According to the present invention, a target compound can be produced more easily than conventional methods, and also a derivative which has been difficult to produce by conventional methods can be produced.

[0013]

EXAMPLES Next, the present invention will be described more specifically by way of examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. Example 1 The following cyclohexylbenzene derivative 1-bromo-4-
(4'-Pentylcyclohexyl) -benzene 4.6 g
Was added to 10 ml of dimethylsulfoxide dehydrated by molecular sieves, 4.9 g of copper powder was added thereto, and the temperature was raised to 110 ° C. to give a fluorine derivative (C ₆ F ₁₃ I) 9.6.
After adding 1.2 g of copper powder, 1.2 g of copper powder was added and reacted at 110 ° C. for 6 hours with stirring. After cooling, 80 ml of chloroform was added to remove insoluble matter by filtration, and the obtained chloroform solution was washed with water and anhydrous sulfuric acid. After drying over sodium, chloroform was distilled off, and the resulting crude product was purified by column chromatography using silica gel to give the following derivative

[0014]

[Chemical 4]

2.8 g were obtained. mp: 38 ° C NMR: δ = 0.88 (3H, t) δ = 7.31 (2H, d) δ = 0.90 to 1.54 (13H, m) δ = 7.48 (2H, d) δ = 1.88 (4H, d) δ = 2.38 (1H, m) MS: 548 (M ⁺ ).

Example 2 The following cyclohexylbenzene derivative 1-bromo-4-
2.8 g of (4'-propylcyclohexyl) benzene was added to 10 ml of dimethylsulfoxide dehydrated by molecular sieves, and 3 g of copper powder was added thereto at 60 ° C.
Fluorine derivative (C ₄ F ₉ I) at the same temperature with heating and stirring
After adding 3.7 g and reacting at the same temperature for 2 hours with stirring, the temperature was gradually raised to 110 ° C., 4 hours later, cooled to 60 ° C., 0.84 g of the above-mentioned fluorine derivative, and copper powder 0.2. 84 g was added, the temperature was gradually raised to 110 ° C. and the reaction was carried out for 6 hours. After cooling, 80 ml of chloroform was added to separate insoluble matter by filtration, and the obtained chloroform solution was washed with water and dried over anhydrous sodium sulfate, and then chloroform was added. The crude product obtained by distillation was purified by column chromatography using silica gel to give the following derivative

[0017]

[Chemical 5]

2.4 g were obtained. mp: 0 ° C NMR: δ = 0.88 (3H, t) δ = 7.31 (2H, d) δ = 0.90 to 1.53 (9H, m) δ = 7.48 (2H, d) δ = 1.88 (4H, d) δ = 2.48 (1H, m)

Example 3 The results shown in Table 1 were obtained by the method according to the above example.

[0020]

[Table 1]

[0021]

[Table 2]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C07C 43/174 8619-4H // C07B 61/00 300

Claims (1)

[Claims] 1. A general formula: (In the formula, X is an iodine atom, a bromine atom, R is a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxyalkyl group,
Indicates an aralkyl group. In the presence of a copper catalyst, a perfluoroalkane represented by the general formula CmF _{2m + 1} Y (wherein Y is an iodine atom, a bromine atom, and m is an integer of 1 to 18) is added to the benzene derivative represented by General formula characterized by reacting below (In the formula, R has the same meaning as in formula (I) above.)
A method for producing a perfluoroalkyl-substituted benzene derivative represented by: