JPH02231474A - Production of n-fluoro-2,3,4,5,6-pentachloro-pyridinium salt - Google Patents

Abstract

PURPOSE:To produce the title compound in high yield safely by reaction between pentachloropyridine, fluorine and a Brphinsted acid or Lewis acid in an acidic lower perfluoro saturated fatty acid as a solvent. CONSTITUTION:In a lower perfluoro saturated fatty acid such as trifluoro-aceteic acid or pentafluoropropionic acid, the reaction of penta-chloropyridine with fluorine and a Brphinsted acid of the formula: XH (X is Brephinsted acid radical) such as trifluoromethanesulfonic acid is effected to give N-fluoro-2,3,4,5,6- pentachloro-pyridinium salt of formula I. Instead of the Brphinsted acid, a Lewis acid is used to effect the reaction to give N-fluoro-2,3-4,5,6-pentachloropyridinium salt of formula II. The product is useful as a reagent for introducing simultaneously a fluorine atom and an acyloxy group into the double bond in an alkene.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to N-fluoro-2 represented by the general formula, [wherein ≠ is ρ or (YFρ. However, X1 and (
Y F) 0 is the conjugate base of the Brønsted acid, and Y is Lewis Shun. ] N-fluoro2.3,
4,5.6-Pentachloroviridinium salt manufacturing method. N-fluoro-2 represented by the general formula (1) of the present invention
．． 3.4.5.6-Pentacroviridinium salt was developed as a trial product for simultaneously introducing a fluorine atom and an acyloxy group into the double bond of an alkene (Reference Example M). [Prior Art] Conventionally, acetylhybofluorite (J. Org. Che+s.
50. 4753 (1985)), trifluoroacetyl hypofluorite (J.Org.Chem..4
5.672 <see 198(1)], or xenon difluoride (Tstrahedron Latt., ) 97
4. 1015) was known. however,
Acetyl hypofluorite and trifluoroacetyl hypofluorite are unstable compounds, so there are problems in handling them. On the other hand, xenon difluoride is expensive because xenon, the basic raw material for its production, is a rare natural resource and there are problems with its supply. Therefore, N-fluoro2.3,4,5.6 can be a useful reagent for this purpose.
- The production of pentac-roviridinium salts is of industrial importance. On the other hand, as a conventional method for producing N-fluoropyridinium salts, a method has been reported in which fluorine, a pyridine compound, and a Brønsted acid compound or a Lewis acid are reacted in a solvent. nitrile,
Methylene chloride, chloroform, carbon tetrachloride, trichlorofluoromethane, trichlorotrifluoroethane, diethyl ether, and tetrahydrofuran are shown (see JP-A-63-10764). However, when using these solvents to react pentachloropyridine, fluorine, and Brennstefed acid or Lewis acid to obtain N-fluoro-2,3,4,5,6-pentachloropyridinium salt, the following drawbacks occur: was there. 1. The reaction yield is low. 2. Reacting pentachloropyridine with low reactivity with fluorine requires a relatively high temperature, so halogenated hydrocarbon solvents (chloroform, carbon tetrachloride, trichlorotrifluoromethane, trichlorotrifluoroethane) are used. However, there is a danger that fluorine may react with the solvent and cause a fire. 3. To eliminate the risk of ignition, the reaction efficiency is poor when carried out at low temperatures, so a large excess of fluorine is required to complete the reaction. 4. Furthermore, in order to eliminate the risk of ignition, fluorine highly diluted with an inert gas must be introduced into the reaction system, which significantly lengthens the time for the reaction to complete, resulting in low production efficiency. 5. Pentachloropyridine has low solubility in acetonitrile, so in this case, a large amount of a7tonitrile solvent and a large excess of fluorine are required to increase the reaction efficiency with fluorine, which is not economical. The production efficiency is low. 6. Freon solvents such as trichloromethane and trichlorotrifluoroethane have low solubility in pentachloropyridine, resulting in poor reaction efficiency with fluorine, and their use is restricted because they cause environmental problems such as depletion of the earth's ozone layer. [Intelligence to be Solved by the Invention] In order to solve these problems, the present invention, as a result of extensive research, has developed an acidic, nonflammable, low-grade solvent that is essentially different from conventionally used solvents. The present invention was completed by discovering the use of Belfluro's saturated fatty acids as a solvent. When the lower saturated fatty acid of the present invention is used as a solvent, N-fluoro2.3.4.5.6-pentafluoroviridinium salt can be reacted with N-fluoro2.3.4.5.6-pentafluoroviridinium salt, which can simultaneously introduce a fluorine atom and an acyloxy group into an alkene. It has good yield and production efficiency, and can be manufactured safely. Means for Solving Cats] In the manufacturing method of the present invention, in the general formula (1), M! e
In the case of a conjugate base of a Brønsted acid where : is represented by
(II) Reacting with the Bronsted acid represented by vP
This is to produce N-fluoro-2.3.4.5.6-pentacroviridinium salt, which is represented by a one-shell formula and has a characteristic. Pentachloropyridine and lower perfluoro saturated fatty acids used in the present invention are industrially easily available compounds. Examples of lower perfluoro saturated fatty acids include trifluoroacetic acid, pentafluorobrobionic acid, hebutafluoroNM,
Examples include heptafluoroisobutyric acid. Further, as the Pronsted acid represented by the general formula (I[), for example, trifluoromethanesulfonic acid, difluoromethanesulfonic acid, trichloromethanesulfonic acid, nonafluorobutanesulfonic acid, heptadefluorooctanesulfonic acid, Brønsted acids such as fluorosulfonic acid, chlorosulfonic acid, sulfuric acid, monomethyl sulfuric acid, perchloric acid, or HBF. , HBC IsF.
, H B C I a, H A I F. , H A I
C l s F SH P F a, HPF. ,HP
CIsF, HAaFa, H A s C l s F
%HAaFh, HSbF4, HSbF and HSbCI. F. , HSbClaF-HSt)Cli
Examples include brenstesodo acid, which is a compound of a Lewis acid such as 1, and hydrogen halide, etc. The reaction temperature is 60°C above the melting point of the lower perfluoro saturated fatty acid used.
Although the range can be selected from 0°C to 40°C, the range is preferably 0°C to 40°C in terms of economical efficiency and good reaction yield. In order to carry out the reaction with good yield, the amount of Bränstefdic acid to be used is equal to or more than equimolar to pentachloropyridine, but taking economic efficiency into consideration, equimolar is preferred. In addition, the fluorine used in the present invention may be used as it is, but in order to control the violent reaction of fluorine, diluted fluorine gas with an inert gas volume of 95% to 25% 4 is used. It is preferable to do so. Examples of the inert gas include nitrogen, helium, and argon. In order to carry out the reaction with good yield, the amount of fluorine used should be equimolar or more than equimolar to pentachloropyridine, but this will vary depending on the method of introducing fluorine, reaction temperature, reaction equipment, etc. The amount of fluorine required for fluorine to react with fluorine and disappear can be selected appropriately. On the other hand, in the above general formula (!), when 1' is (YF)9, the production method of the present invention involves pentachloropyridine and fluorine (F,) in the lower perfluoro saturated fatty acid.
and a Lewis acid represented by the general formula Y - (IN),
This is to produce N-fluoro-2.3.4,5.6-pentachloroviridinium salt represented by the general formula. The Lewis acid represented by the general formula (III) used in the present invention includes BFs, BC 1, AIF, AICI,
,PF,,P F s%P C l s,AsF,,^
sCE@, AsFa, SbFg, S b F,, SbC
Examples include 1 mFs, SbCI SOs, etc.
These Lewis acids may also be used as compounds for various ethers and nitrile compounds. In order to carry out the reaction with good yield, the amount of Lewis acid to be used is equal to or more than the same mole relative to pentachloropyridine, but taking economic efficiency into account, equimolar is preferred. Furthermore, the usage forms of the lower perfluorinated saturated fatty acids and fluorine used in this reaction are the same as in the above method. The reaction temperature for this reaction can be selected from a range above the melting point of the lower Verfluorescent saturated fatty acid to 60°C, but a range of 0°C to 40°C is preferred from the viewpoint of economical efficiency and good yield. [Effects of the Invention] As described above, the production method of the present invention provides N as a stable and easy-to-handle reagent that can simultaneously introduce a fluorine atom and an acyloxy group into the double bond portion of an alkene.
- A method for producing fluoro-2.3,45,6-pentachloroviridinium salt in a safe manner and with good yield.

The present invention will be explained in more detail below using Examples and Reference Examples. Example I CI 40 ml of trifluoroacetic acid, 1 part of pentachloropyridine
0.06g (40mmo +) and to! J7 Fluoromethanesulfone M3.53ml (40mmo I)
A mixed gas of 2:8 of fluorine and nitrogen was introduced at a flow rate of 50 ml/min into the container containing the solution at room temperature while stirring (the number of moles of fluorine used was 123 mmol). Thereafter, residual fluorine was removed by flushing with nitrogen, the solvent was distilled off, and dry ethyl acetate was added. The precipitated crystals were filtered off to obtain 12.12 g of N-fluoro-2.3,4,5.6-pentacyclopyridinium trifluoromethanesulfonate (yield: 72%). Physical property values and spectral data are shown below. Melting point: 3122-123°C "F-NMR (based on trichlorofluoromethane in acetonitrile): -48.0 ppm (s, N-F), 78
．． 2ppm (s.CF,), ? 7, Spectrum (m/e)! 268,270272.
274. Elemental analysis: Actual value: C. 17.31 94; H. O%
;N, 3.43%. Calculated value i C, 17.18%; H
, 09AEN, 3.34%. Example 2 Ml 40 ml of trifluoroacetic acid and 1 of pentachloropyridine
O. 06 g (40 mmo!)
F s gas was absorbed until it was no longer absorbed ( B F
The yield of s was 40 mmoJ》. After biting, the solution became a homogeneous solution. A 2:8 mixture of fluorine and nitrogen was poured into the container containing the solution at room temperature for 48 hours.
The amount of fluorine used to be introduced at a flow rate of ml/min was 1
(20 mmol). Thereafter, residual fluorine was removed by flushing with nitrogen, the solvent was distilled off, and dry ethyl acetate was added. The precipitated crystals were filtered to obtain 26.16 g of N-fluoro 2.3,4,5.6-pentachloroviridinium tetrafluoroborate (yield 92%).
．． Physical property values and spectral data are shown below. Melting point: 1
98-200°C (in a sealed tube under argon atmosphere) F-NMR (internal standard of trichlorofluoromethane in acetonitrile): -47.6 ppm (s, N-F),
+152.6ppm (s, BF4). Mass spectrum (m/θ): 287, 289, 29
1,293. Elemental analysis: Actual value + 0. 16.93%; H, 0%; N. 3.9
1%. Calculated value. C, 16.82%; H, 0%. N, 3.
92%. Example 3 The physical properties and spectral data of the CI product are shown in the section of Example 1. Reference Example 1 In a container containing a solution of 10 ml of Cl pentafluorobrobionic acid, 2.52 g (10 mmol) of pentachloropyridine, and 0.88 ml (10 mmol) of trifluoromethanesulfonic acid, a mixture of fluorine and nitrogen was added while stirring at room temperature. 8 mixed gas was introduced at a flow rate of 30 ml/min (the molar loss of fluorine used was 3 Q mmol). Post-treatment was carried out in the same manner as in Example 1 to obtain 3.47 g (yield: 83%) of N-fluoro-2.3,4,5,6-pentacro-viridinium trifluoromethanesulfonate. 2 ml of acetic acid and 423 μl of N-2.3.4,5.6-be7tachloroviridinium trifluoromethanesulfonate (lm
114 μj (lmmol) of styrene in a mixture with
1) was added and stirred at room temperature for 165 hours. After the reaction, water was added to the reaction solution and ether extraction was performed. The ether layer was washed with water, dried over magnesium sulfate, and then the solvent was distilled off. The resulting residue was purified by silica gel chromatography to obtain 117w of 1-acetoxy-1-phenyl-2
-Fluoroethane was obtained as an oil (yield 63%).
The physical property values and spectral data of the product are shown below. Boiling point: 190-200℃ (bath temperature) /63-65 Hg
．． IH-NMR (in deuterated chloroform): δ2. l1←
l. CHs), 4.50 (dm, J-4 8.0Hz
, CHt), 6.03 (d d d, J-1 6.8
, 6.5.4.5Hz, CH), 7.34 (s, aromatic nuclear hydrogen). 19F-pJMR (internal standard of trichlorofluoromethane in 1 chloroform): 223.8pp
m(dt, J-16.8.48.0Hz). IR (n
eat): 1740cm-' (ester). Mass spectrum (m/e) + 1 8 2 (M').
Elemental analysis: Actual value iC, 65.699HH, 6.25%. needle value i
C, 65.93%. H, 6.09%. Reference Example 2 CI 1.07 g of N-fluoro2.3.4,5.6-pencchloroviridinium tetrafluoroborate in a solution of 6 ml of acetic acid and 343 μl (3 mmol I) of styrene
(3 mma 1) was added and stirred at room temperature for 3 hours. After the reaction, the same post-treatment as in Reference Example 1 was carried out, and 0.30 g of 1
-acetoxy-1-phenyl-2-fluoroethane was obtained (yield 55%). The physical properties and spectral data of the product were the same as those shown in Reference Example 1.

Claims (2)

[Claims] (1) There are general formulas ▲ mathematical formulas, chemical formulas, tables, etc. ▼ that are characterized by reacting pentachloropyridine, fluorine, and Prensted acid represented by the general formula A method for producing an N-fluoro-2,3,4,5,6-pentachloropyridinium salt (wherein X^■ is a conjugate base of a Pronsted acid). (2) characterized by reacting pentachloropyridine, fluorine, and a Lewis acid represented by the general formula Y in a lower perfluorosaturated fatty acid;
A method for producing N-fluoro-2,3,4,5,6-pentachloropyridinium salt represented by the general formula ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (in the formula, Y is a Lewis acid).