JPS60130537A - Preparation of aromatic fluorine compound - Google Patents

Abstract

PURPOSE:To obtain the titled compound by one stage efficiently, by using an active halogen-containing compound and a phase transfer catalyst, reacting an aromatic nitro compound with a metal fluoride in a specific solvent so that NO2 group of aromatic nucleous a replaced with F effectively. CONSTITUTION:An aromatic nitro compound shown by the formula I (X and Y are Cl, Br, F, or H; with the proviso that X=Ynot equal to ; R<1>-R<3> are Cl, Br, F, or NO2, CN, CF3 or H) is fluorinated with a metal fluoride such as preferably KF, etc. in an aprotic polar solvent such as especially preferably sulfolane, etc. in the presence of an active halogen-containing compound shown by the formula II (Z is Cl, Br, or F; n is 1-3), formula III, etc. and a phase transfer catalyst shown by the formula IV (A<1>-A<3> are alkyl, aryl or combination of them, B is Cl or Br) or formula V at 100-200 deg.C at 1-5kg/cm<2> pressure for 1-30hr, to give the desired compound shown by the formula IV R<4>-R<6> are as shown for R<1>-R<4>).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for obtaining an aromatic fluorine compound by converting an aromatic nitro compound with metal 7/I/olide in the presence of an active halogen-containing compound and a phase transfer catalyst.

Aromatic nitro compounds are treated with dimethylformamide (DMF
It is sometimes abbreviated as ) in an aprotic solvent such as
It is known to obtain aromatic fluorine compounds by reacting with metal fluorides such as potassium fluoride, but the yield is extremely low.

For example, in the following reactions, the yield is 10
It is known that it is about 100%.

Generally, the reaction of substituting the NOx group of an aromatic nucleus with 1 has a low yield, but the reason for this is that the reaction products KN(h and its decomposition products 1(go, NO2, etc.) react with the starting materials and the target compound. It is believed that this is because

The present inventors have conducted intensive research on a method for obtaining aromatic fluorine compounds from aromatic nitro compounds in good yield, and have found that the fluorination reaction can be carried out in the presence of an active halogen-containing compound and a phase transfer catalyst. I found it to be effective. That is, in the present invention, an aromatic nitro compound represented by the following general formula (1) is reacted with a metal fluoride in an aprotic polar solvent in the presence of an active halogen-containing compound and a phase transfer catalyst. The present invention relates to a method for producing an aromatic fluorine compound, which is characterized by obtaining an aromatic fluorine compound represented by formula (II).

(In the formula, X and Y are respectively 01.13r, F or R1
However, H is excluded for both X and Y.

R1, R2, H& are each 01. fir, F,
N(M, ON.

Indicates ays or H.

R', R', R' are each 01. Br,
F, NCH, ON.

Indicates OFm or H. ) The aromatic nitro compound in the present invention is a compound represented by the general formula (2) and having at least one nitro group and at least one halogen atom such as 01.11r F. At least one nitro group or halogen atom is bonded to an adjacent carbon of the aromatic nucleus.On the other hand, 7 of NCH
The aromatic fluorine compound obtained by substitution is represented by the general formula (n). In general formulas (1) and (It), X and Y are each 01. Br? or H,
Both XY include combinations other than ■.

Also, R1, R1, and RA are CI, Br, F, respectively.
NOI.

ON, OFm or H, and a combination of one to three of these. Further, R4, R11, and R6 are also each Ol.

Br, F, NO2, ON, OFm or H,
It is a combination of 1 to 3 of these.

Examples of the aprotic polar solvent as a reaction solvent include acetonitrile, dimethylformamide, dimethylsulfoxide, sulfolane, 1q-methyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, hexamethylphosphortriamide, 1.3 -dimethyl-2-imidazolidinone, etc., and sulfolane and 1,3-dimethyl-2-imidazolidinone are particularly preferred.

The amount of the solvent to be used is not particularly limited, but an appropriate amount is 0.2 to 10 times, preferably 1 to 5 times, the amount of f- in parts relative to the aromatic nitro compound as the starting material.

Examples of metal fluoride as a fluorinating agent include KF,
RbF, OsF, etc. are preferred, and the amount used is determined according to the theoretical reaction amount necessary for replacing the NO2 group to be replaced with fluorine in the aromatic nitro compound and the amount required for fluorination of the active halogen-containing compound. The appropriate amount is 1 to 3 times, preferably 1 to 2 times, the theoretical reaction amount required for the reaction.

In the present invention, the presence of an active nitrogen-containing compound and a phase transfer catalyst is effective in promoting the fluorine substitution reaction of 102 groups. The active logen-containing compound is preferably a compound represented by the following general formulas (Ill) to (Vll).

CC13-(S02z) m=-1~2! IF number −
---(IV) (However, in the formula, 2 is a halogen atom such as 01. Br, F, etc.) The phase transfer catalyst has the following general formula ((Company) ~
A compound represented by (IX) is preferred.

(However, in the formula A', A", A', , A'
The same or different alkyl groups, the same or different aryl groups, or a combination of these alkyl groups and aryl groups. B represents 01 or Br. ) The amount of the active halogen-containing compound to be added is 10 to 300 parts by weight, preferably 50 to 200 parts by weight, per 10* parts of the aromatic nitro compound as the starting material. The amount added is 5 to 100 parts by weight, preferably 1
It may be selected from the range of 0 to 50 parts by weight.

The reaction conditions such as reaction temperature, time, and pressure may be appropriately selected, but the temperature is about 100-200°C, 1-5Kp15! can be carried out at a pressure of 1 to 30 hours and a reaction time of 1 to 30 hours. According to the second invention, NO2 of the aromatic nucleus
Since the group can be effectively substituted with fluorine, there is no need to go through the conventionally advantageous three-step reaction of reduction of the Not group - diazofluorination -> thermal decomposition, and the target compound can be obtained in a high yield in one step. Obtainable.

Examples of the present invention will be described in more detail below.

Comparative Example 1 3-chloro-2-fluoronitrobenzene 102, Sulfolaf 40CC and dry KF 109 were added to a 200cc glass reactor and reacted at 200'C for 6 hours.

Analysis of the reaction solution by gas chromatography revealed that the reaction rate of the raw materials was 85%, and the selectivity to 2°3-difluorochlorobenzene was 2%.

Example 1 10 tons of 3-chloro-2-fluoronitrobenzene, 40 CC17 of sulfolane, 5 tons of taric acid fluoride, 2.52 tons of tetramethylammonium chloride, and 10 dry KF were added to a 200 cc glass reactor, and the mixture was reacted at 150'C for 10 hours. Process, reaction rate of raw materials 7Ochi, 2.3-
The selectivity to difluorochlorobenzene was 60%.

Example 2 In a 200 cc glass reactor, 10 f of 3-chloro-2-fluoronitrobenzene, 40 cc of sulfolane, and 59 cc of 7-taloyl chloride were added. Add 2.5t of tetrabutylammonium chloride and dry 0sF202 and heat at 130℃ for 2 hours.
When reacted for a period of time, the reaction rate of the raw materials was 54%, and the selectivity to 2,3-difluorochlorobenzene was 84%.

Examples 3 to 6 Table 1 shows the results obtained under the same persimmon conditions as in Example 2, but in which various additives were added in place of heptalyl chloride.

Table-1 Example 7 Autoclay 7' made of 5ue-316 equipped with paper stirring/equipment
K, 3-10 rho 2-fluoronitrobenzene 20P,
1.3-dimethyl-2-imidazolidinone (1; M engineering)
socc17 talic acid chloride 10f.

Tetraptylan-vinyram chloride 5t and 8pra
Add 202 7 ”k, k'iL K F, 175℃
After reacting at ~180'C for 2 hours, the reaction of the raw material 4S
19%, selectivity to 2.3-difluorobenzene 63
It was Chi.

Comparative Example 2 20% of 3-chloro-2-fluoronitrobenzene was added to the apparatus used in Example 7. , 2 of DM Engineering 80Ce and 5pray dry I#xF were added and reacted at 175°C to 180°C for 2 hours, and the reaction rate of the raw material to 23q6.2.3-difluorobenzene was less than 1%. .

Example 8 20% of 2-fluoronitrobenzene was added to a 200% CC5uS-31615 auto v-7 equipped with a stirring device.
1. Benzoic acid chloride IOf, Sulfolaf 80 cc
, OeF 20? When the reaction was carried out at 160° C. for 3 hours, the reaction rate of the raw materials was 35%, and the selectivity to 0-difluorobenzene was 48%. When benzoyl chloride was not added, the reaction rate of the raw material was 48% and the selectivity to O-difluorobenzene was 18% under the same conditions.

Example 9 m-dinitrobenzene IO in a 200cc glass reactor
P, sulfone 6O-, phthalic acid fluoride as l0I
F, 5pray dry KF 20 f added, 1 at 180℃
After 0 hours of reaction, the reaction rate of the raw materials was 58% and the selectivity to m-fluoronitrobenzene was 67%. When phthalic acid fluoride is not added, under the same conditions, the reaction rate of the raw material is 54%, and the selectivity to m-fluoronitrobenzene is 3.
It was 9chi.

Procedural Amendment Statement March 7, 1980 Kazuo Wakasugi, Commissioner of the Japan Patent Office1, Indication of the case, Patent Application No. 236085, filed in 1982, 2, Name of the invention, Production of aromatic fluorine compounds i3, Person making the amendment. Related Patent Applicant Address 2-1-2 Marunouchi, Chiyoda-ku, Tokyo Name (
004) Asahi Glass Co., Ltd. voluntary amendment 6, number of inventions increased due to amendment None? , Detailed explanation of the invention column 8 of the specification subject to amendment, Contents of amendment (1) Page 6 of the specification, line 6 from the top, “Active halogen-containing/
The description ``\halogenide...'' has been corrected to ``active halogen-containing compound...''.

(2) In the first line from the top of page 512 of the specification, the statement "2,3-difluorobenzene..." is corrected to the statement "2,3-difluorochlorobenzene...".

that's all

Claims (1)

[Claims] (1) An aromatic nitro compound represented by the following general formula (1) is reacted with a metal fluoride in an aprotic polar solvent in the presence of an active halogen-containing compound and a phase transfer catalyst to form the following general formula (n ) is a patented process for producing aromatic fluorine compounds. "(In the formula, X and Y are each 01. Br, F or ■,
However, H is excluded for both X and Y. R', R2, R'' are respectively O'l, Br, F
, NO3°ON, OFj, or H. R4, Ha, H6 are Olv Br, F, respectively
Indicates NOx +ON, OFs, or ■)