GB2039473A - Reaction of a chlorinated pyridine with an alkali metal fluoride - Google Patents
Reaction of a chlorinated pyridine with an alkali metal fluoride Download PDFInfo
- Publication number
- GB2039473A GB2039473A GB7901122A GB7901122A GB2039473A GB 2039473 A GB2039473 A GB 2039473A GB 7901122 A GB7901122 A GB 7901122A GB 7901122 A GB7901122 A GB 7901122A GB 2039473 A GB2039473 A GB 2039473A
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- United Kingdom
- Prior art keywords
- compound
- fluoropyridine
- prepared
- fluoropyridine compound
- dichloro
- Prior art date
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- Granted
Links
- 229910001515 alkali metal fluoride Inorganic materials 0.000 title claims abstract description 18
- 150000003222 pyridines Chemical class 0.000 title description 2
- -1 fluoropyridine compound Chemical class 0.000 claims abstract description 51
- 238000000034 method Methods 0.000 claims abstract description 43
- 239000011698 potassium fluoride Substances 0.000 claims abstract description 20
- 150000001875 compounds Chemical class 0.000 claims abstract description 18
- NROKBHXJSPEDAR-UHFFFAOYSA-M potassium fluoride Chemical compound [F-].[K+] NROKBHXJSPEDAR-UHFFFAOYSA-M 0.000 claims abstract description 17
- DNDPLEAVNVOOQZ-UHFFFAOYSA-N 2,3,4,5,6-pentachloropyridine Chemical compound ClC1=NC(Cl)=C(Cl)C(Cl)=C1Cl DNDPLEAVNVOOQZ-UHFFFAOYSA-N 0.000 claims abstract description 16
- 239000003054 catalyst Substances 0.000 claims abstract description 13
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims abstract description 10
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 9
- 235000003270 potassium fluoride Nutrition 0.000 claims abstract description 9
- 229910052731 fluorine Inorganic materials 0.000 claims abstract description 8
- 239000011737 fluorine Substances 0.000 claims abstract description 8
- 150000004820 halides Chemical class 0.000 claims abstract description 6
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 5
- 230000003197 catalytic effect Effects 0.000 claims abstract description 4
- 229910052742 iron Inorganic materials 0.000 claims abstract description 4
- 238000004519 manufacturing process Methods 0.000 claims abstract description 4
- 229910052751 metal Inorganic materials 0.000 claims abstract description 4
- 239000002184 metal Substances 0.000 claims abstract description 4
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims abstract description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical group [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 3
- 239000000460 chlorine Substances 0.000 claims abstract description 3
- 229910052801 chlorine Inorganic materials 0.000 claims abstract description 3
- 150000002739 metals Chemical class 0.000 claims abstract description 3
- 239000000203 mixture Substances 0.000 claims description 15
- PKSORSNCSXBXOT-UHFFFAOYSA-N 3,5-dichloro-2,4,6-trifluoropyridine Chemical group FC1=NC(F)=C(Cl)C(F)=C1Cl PKSORSNCSXBXOT-UHFFFAOYSA-N 0.000 claims description 11
- 125000000217 alkyl group Chemical group 0.000 claims description 11
- MTAODLNXWYIKSO-UHFFFAOYSA-N 2-fluoropyridine Chemical compound FC1=CC=CC=N1 MTAODLNXWYIKSO-UHFFFAOYSA-N 0.000 claims description 10
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 claims description 7
- 125000004432 carbon atom Chemical group C* 0.000 claims description 7
- 239000002904 solvent Substances 0.000 claims description 7
- 239000001257 hydrogen Substances 0.000 claims description 6
- 229910052739 hydrogen Inorganic materials 0.000 claims description 6
- 239000000376 reactant Substances 0.000 claims description 6
- 150000003839 salts Chemical class 0.000 claims description 6
- FATBKZJZAHWCSL-UHFFFAOYSA-N 2,3,5,6-tetrachloropyridine Chemical compound ClC1=CC(Cl)=C(Cl)N=C1Cl FATBKZJZAHWCSL-UHFFFAOYSA-N 0.000 claims description 4
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 4
- 125000001309 chloro group Chemical group Cl* 0.000 claims description 4
- MBTGBRYMJKYYOE-UHFFFAOYSA-N 2,6-difluoropyridine Chemical group FC1=CC=CC(F)=N1 MBTGBRYMJKYYOE-UHFFFAOYSA-N 0.000 claims description 3
- AYTUSKIZXVPKBR-UHFFFAOYSA-N 3,5-dichloro-2,6-difluoropyridine Chemical group FC1=NC(F)=C(Cl)C=C1Cl AYTUSKIZXVPKBR-UHFFFAOYSA-N 0.000 claims description 3
- 229910001220 stainless steel Inorganic materials 0.000 claims description 3
- 239000010935 stainless steel Substances 0.000 claims description 3
- FILKGCRCWDMBKA-UHFFFAOYSA-N 2,6-dichloropyridine Chemical compound ClC1=CC=CC(Cl)=N1 FILKGCRCWDMBKA-UHFFFAOYSA-N 0.000 claims description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 claims description 2
- 239000004411 aluminium Substances 0.000 claims description 2
- 229910052782 aluminium Inorganic materials 0.000 claims description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 2
- 229910052787 antimony Inorganic materials 0.000 claims description 2
- WATWJIUSRGPENY-UHFFFAOYSA-N antimony atom Chemical compound [Sb] WATWJIUSRGPENY-UHFFFAOYSA-N 0.000 claims description 2
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 claims description 2
- 125000004435 hydrogen atom Chemical group [H]* 0.000 claims description 2
- 239000000463 material Substances 0.000 claims description 2
- 230000001069 nematicidal effect Effects 0.000 claims description 2
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 claims description 2
- 230000002363 herbicidal effect Effects 0.000 claims 3
- CISUDJRBCKKAGX-UHFFFAOYSA-N 3-fluoro-1h-pyridin-2-one Chemical compound OC1=NC=CC=C1F CISUDJRBCKKAGX-UHFFFAOYSA-N 0.000 claims 2
- JPMASQTVFRLSAV-UHFFFAOYSA-N 4-amino-3,5-dichloro-6-fluoro-1h-pyridin-2-one Chemical compound NC1=C(Cl)C(O)=NC(F)=C1Cl JPMASQTVFRLSAV-UHFFFAOYSA-N 0.000 claims 2
- 159000000000 sodium salts Chemical class 0.000 claims 2
- BEGINUFBBRTGBH-UHFFFAOYSA-N 3,5-dichloro-2,6-difluoropyridin-4-amine Chemical compound NC1=C(Cl)C(F)=NC(F)=C1Cl BEGINUFBBRTGBH-UHFFFAOYSA-N 0.000 claims 1
- 241000244206 Nematoda Species 0.000 claims 1
- 125000003277 amino group Chemical group 0.000 claims 1
- 150000001649 bromium compounds Chemical group 0.000 claims 1
- 125000001246 bromo group Chemical group Br* 0.000 claims 1
- 239000004035 construction material Substances 0.000 claims 1
- 125000001153 fluoro group Chemical group F* 0.000 claims 1
- 230000002401 inhibitory effect Effects 0.000 claims 1
- 150000005754 fluoropyridines Chemical class 0.000 abstract description 6
- 238000002360 preparation method Methods 0.000 abstract description 6
- 229910021578 Iron(III) chloride Inorganic materials 0.000 abstract description 2
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 abstract description 2
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 abstract 1
- 239000007858 starting material Substances 0.000 description 4
- IKZSQJOVXGDGAH-UHFFFAOYSA-N 2,3,4,5-tetrachloro-6-fluoropyridine Chemical compound FC1=NC(Cl)=C(Cl)C(Cl)=C1Cl IKZSQJOVXGDGAH-UHFFFAOYSA-N 0.000 description 3
- UXUZMYHSICIOQT-UHFFFAOYSA-N 3-chloro-2,4,5,6-tetrafluoropyridine Chemical compound FC1=NC(F)=C(Cl)C(F)=C1F UXUZMYHSICIOQT-UHFFFAOYSA-N 0.000 description 3
- 239000011541 reaction mixture Substances 0.000 description 3
- HEDRZPFGACZZDS-UHFFFAOYSA-N Chloroform Chemical compound ClC(Cl)Cl HEDRZPFGACZZDS-UHFFFAOYSA-N 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 230000001419 dependent effect Effects 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- PUZPDOWCWNUUKD-UHFFFAOYSA-M sodium fluoride Chemical compound [F-].[Na+] PUZPDOWCWNUUKD-UHFFFAOYSA-M 0.000 description 2
- HXJUTPCZVOIRIF-UHFFFAOYSA-N sulfolane Chemical compound O=S1(=O)CCCC1 HXJUTPCZVOIRIF-UHFFFAOYSA-N 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- WXUKVOVSTRWNSA-UHFFFAOYSA-N 2,3,5-trichloro-4,6-difluoropyridine Chemical compound FC1=NC(Cl)=C(Cl)C(F)=C1Cl WXUKVOVSTRWNSA-UHFFFAOYSA-N 0.000 description 1
- BNUSSTHQAKYHIS-UHFFFAOYSA-N 2,3,5-trichloro-6-fluoropyridine Chemical compound FC1=NC(Cl)=C(Cl)C=C1Cl BNUSSTHQAKYHIS-UHFFFAOYSA-N 0.000 description 1
- MSGCMOGAEFPFDE-UHFFFAOYSA-N 3,5-dichloro-2,4-difluoropyridine Chemical compound FC1=NC=C(Cl)C(F)=C1Cl MSGCMOGAEFPFDE-UHFFFAOYSA-N 0.000 description 1
- CPELXLSAUQHCOX-UHFFFAOYSA-M Bromide Chemical compound [Br-] CPELXLSAUQHCOX-UHFFFAOYSA-M 0.000 description 1
- STECJAGHUSJQJN-USLFZFAMSA-N LSM-4015 Chemical compound C1([C@@H](CO)C(=O)OC2C[C@@H]3N([C@H](C2)[C@@H]2[C@H]3O2)C)=CC=CC=C1 STECJAGHUSJQJN-USLFZFAMSA-N 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- WAIPAZQMEIHHTJ-UHFFFAOYSA-N [Cr].[Co] Chemical compound [Cr].[Co] WAIPAZQMEIHHTJ-UHFFFAOYSA-N 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- TVFDJXOCXUVLDH-UHFFFAOYSA-N caesium atom Chemical compound [Cs] TVFDJXOCXUVLDH-UHFFFAOYSA-N 0.000 description 1
- XJHCXCQVJFPJIK-UHFFFAOYSA-M caesium fluoride Inorganic materials [F-].[Cs+] XJHCXCQVJFPJIK-UHFFFAOYSA-M 0.000 description 1
- 150000005753 chloropyridines Chemical class 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004817 gas chromatography Methods 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 239000004009 herbicide Substances 0.000 description 1
- 239000000543 intermediate Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000005645 nematicide Substances 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 239000000575 pesticide Substances 0.000 description 1
- 239000003880 polar aprotic solvent Substances 0.000 description 1
- JUJWROOIHBZHMG-UHFFFAOYSA-N pyridine Substances C1=CC=NC=C1 JUJWROOIHBZHMG-UHFFFAOYSA-N 0.000 description 1
- UMJSCPRVCHMLSP-UHFFFAOYSA-N pyridine Natural products COC1=CC=CN=C1 UMJSCPRVCHMLSP-UHFFFAOYSA-N 0.000 description 1
- 239000012429 reaction media Substances 0.000 description 1
- 235000013024 sodium fluoride Nutrition 0.000 description 1
- 239000011775 sodium fluoride Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000011592 zinc chloride Substances 0.000 description 1
- 235000005074 zinc chloride Nutrition 0.000 description 1
- JIAARYAFYJHUJI-UHFFFAOYSA-L zinc dichloride Chemical compound [Cl-].[Cl-].[Zn+2] JIAARYAFYJHUJI-UHFFFAOYSA-L 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D213/00—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members
- C07D213/02—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members
- C07D213/04—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom
- C07D213/60—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
- C07D213/61—Halogen atoms or nitro radicals
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Pyridine Compounds (AREA)
Abstract
A process for preparing a fluoropyridine compound by reacting a chlorinated pyridine compound with a molar access of an alkali metal fluoride, especially potassium fluoride, in the presence of a catalytic amount of a catalyst selected from halides of organo-metals and halides of metals of the iron, nickel and copper groups, and which is preferably FeCl3, whereby the or at least one chlorine of the chlorinated pyridine compound is replaced by fluorine. Of especial interest is the preparation of 3,5-cidhloro-2,4,6-trichloropyridine from pentachloropyridine. The compounds prepared by such a process are useful for the preparation of agriculturally-useful fluoropyridines.
Description
SPECIFICATION
Reaction of a chlorinated pyridine with an alkali metal fluoride
This invention concerns an improvement in the reaction of a chlorinated pyridine compound with an alkali metal fluoride. Products of the reaction are useful as intermediates forthe preparation of herbicides or pesticides.
It is known to react chloropyridines with potassium fluoride in a polar aprotic solvent in the pres ence of a small amount of water to effect replace mentofchlorine by fluorine. Reaction of anhydrous
KF with pentachloropyridine in 5.9:1 mole ratio in sulpholane and water at 215 C has given 91% yield of 3, 5 - dichlorotrifluoropyridine, 6% yield of 3 chlorotetrafluoropyridine, and 3% yield of 3,4, 5, 6 tetrach lorofluoropyridine (British Patent Specification No. 1,256,082). Reaction of KF with pentachloropyridine in 11:1 mole ratio at 400"C for 18 hours in the absence of solvent has given 84% yield of 3,5 dichloro - 2,4,6 - trifluoropyridine (J. Chem. Soc.
1964,3573). Reaction of KF with pentachloropyridine in 9.5:1 mole ratio at 400"C for 5 hours in the absence of solvent has given 45% yield of 3, 5 - dichlorotrifluoropyridine and 19% yield of 3 - chlorotetrafluoropyridine (J. Chem. Soc. 1965, 594).
We have now found that certain compounds are effective catalysts for the reaction and that carrying out the reaction in the presence of a small amount of one or more of these compounds permits use of less alkali metal fluoride and lower temperatures than heretofore for preparing a given desired product in good yield.
Accordingly, the present invention provides a process for preparing a fluoropyridine compound, which process comprises reacting a chlorinated pyridine compound with a molar excess of an alkali metal fluoride in the presence of a catalytic amount of a catalyst selected from halides of organometals and halides of metals of the iron, nickel and copper groups, whereby the or at least one chlorine of the chlorinated pyridine compound is replaced by fluorine. The desired product may be isolated by distillation.
The starting material may be any pyridine compound containing at least one chlorine substituent on the ring. The useful starting materials include, for example, the mono-, di-, tri-, tetra- and pentachloropyridines, depending on the particular product or products desired. When the starting material is a polychloropyridine, the number of chlorine atoms replaced by fluorine is believed to be dependent on the temperature and time of reaction employed, the higher temperatures and longer times of reaction favouring more replacement by fluorine.The process of the invention is of especial interest for the preparation of 3, 5 - dichloro - 2,4, 6 - trichloropyridine from pentachloropyridine, and of inter estforthe preparation of3, 5 - dichloro - 2,6 - dif- luoropyridine from 2,3, 5, 6 - tetrachloropyridine and of 2, 6 - difluoropyridine from 2, 6 - dichloropyridine.
The alkali metal fluoride used in the process ofthe present invention may be caesium, potassium or sodium fluoride. The use of potassium fluoride is preferred.
As indicated above, it is essential to use a molar excess of the alkali metal fluoride. Preferably, the amount of alkali metal fluoride employed is 10 to 100%, more preferably 10 to 50%, in excess of the theoretical amount of fluorine required to produce the desired fluoropyridine.
An essential feature of the present process is the utilization of a catalyst selected from those listed above, such as, for example, a bromide or chloride of aluminium, antimony, or iron. Preferred catalysts include SbCI3, AICI3, ZnCl2 and FoCI3, with the latter being most preferred. In order to obtain the benefits of the present invention, it is also essential that the catalyst be employed in an amount sufficient to provide a catalytic effect. Having regard to economy and ease of carrying out the reaction, the catalyst is generally employed in an amount of from 0.5 to 10, pref erablyfrom 1 to 5, more preferably from 1 to 3, percent by weight based on the amount of the alkali metal fluoride.
For economic reasons, it is generally preferred to carry out the reaction of the process of this invention without the use of a solvent, although the reaction can be run in the presence of a solvent or reaction medium, such as sulpholane.
Although the reaction can be carried out successfully in glass equipmentglassissusceptible to attack by alkali metal fluorides, and it may be desirable to employ a greater amount of the alkali metal fluoride than the preferred amounts indicated above.
In view of this, it is preferred to carry out the reaction in equipment in which the parts contacted by the reactants are constructed of material that is inert to alkali metal fluorides, such as stainless steel, nickel or Hastelloy C (Registered Trade Mark).
The conditions under which the reaction is carried out are such that the reactants are in their liquid or gaseous states. Below 150"C there is a tendency for the reactants to be in their solid states, and accordingly it is preferred to carry out the reaction at a temperature within the range of from 150 to 4000C, more preferably at a temperature within the range of from 250 to 350"C. The reaction is preferably carried out in sealed vessels necessitating elevated pressures which are dependent on the temperatures used and the number of moles of starting material.
Typically at 3000C the pressure is in the range of from 50 to 200 psig.
A particularly preferred process of the present invention comprises reacting in a sealed inert vessel pentachloropyridine with from 3.3 to 4.5 moles of potassium fluoride per mole of the pentachloropyridine in the presence of from 1 to 3 percent by weight of FeCI3 based on the amount of potassium fluoride and in the absence of a solvent at a temperature within the range of from 250 to 350"C, and recovering 3, 5 - dichloro - 2,4, 6 - trifluoropyridine
Certain of the chemical formula(e) appearing in the printed specification were submitted in formal form after the date
of filing.
as the principal product
The fluoropyridine compounds prepared by a process according to the present invention are particu larly useful forthe preparation of agriculturallyuseful fluoropyridines. Examples of such agriculturally-useful fluoropyridines are as follows: (a) Compounds of general formula:
wherein each X independently represents chloro, bromoorfluoro; R represents-CONR3R4(where R3 and R4 independently each represents hydrogen or alkyl containing from 1 to 8 carbon atoms),-COOH or a salt thereof, or-COOR5 (where R5 represents alkyl containing from 1 to 12 carbon atoms or QCH2)nOR5 where n represents an integer of from 2 to 4 and R. represents lower alkyl or phenyl); and M represents hydrogen or lower alkyl.
Such compounds, agriculturally-useful compositions containing them, and their uses are described an claimed in British Patent Specification No.
1,418,979.
(b) Compounds of general formula:
and salts, including amine salts thereof, wherein R1 represents hydrogen or an alkyl group having from 6 to 16 carbon atoms. R1 may be an alkyl group having 8 carbon atoms. Some of these compounds are within the scope of formula (I) above and accordingly are within the scop of claim 1 of British Patent
Specification No. 1,418,979.
(c) Acompoundofformula:
(d) A compound of formula
Any agriculturally-useful fluoropyridine, including those specified in (a) to (d) above, which has been prepared directly or indirectly from a fluoropyridine prepared by a process according to the present invention is within the scope of the present invention. So is an agriculturally-useful composition comprising any such agriculturally-useful fluoropyridine.
Those compounds specified in (a) to (c) above are herbicidally active and the compound specified in (d) above is a nematocide.
The agriculturally-useful fluoropyridines can be prepared from the fluoropyridines prepared by the process of the present invention by any appropriate route. A typical example of such a route is as follows:
where R' is as defined above.
It will be apparent to those skilled in the art that a wide range of agriculturally-useful fluoropyridine can be prepared from a fluoropyridine which has been prepared by the process according to the present invention.
In order that the present invention may be more fully understood, the following Examples are given primarily by way of illustration and should not be construed as limitations upon the overall scope of the present invention.
Example I
A mixture of 100 g potassium fluoride and 1 g ferric chloride was prepared by grinding together the two components. In like manner, 2 g (0.008 mole) of pentachloropyridine were mixed with 1.87 g (0.032 mole) KF) of the KFlFeCI3 mixture. The mixing operations were carried out in a dry nitrogen atmosphere.
The mixture of the reactants was placed in a stain
less steel cylinder and the cylinder sealed. Then the
cylinder and contents were heated in a furnace at 300"C for 16 hours. After cooling, the contents were
extracted with chloroform and filtered. Analysis by
gas chromatography indicated an 83 percent yield of 3, 5 - dichloro - 2,4,6 - trifluoropyridine and a 4 percent yield of 3 - chloro - 2,4, 5, 6 - tetraf
luoropyridine.
Example 2
The method of this Example was similar to that of
Example 1 except as follows. The reaction mixture
contained 3.74 g. (0.64 mole KF) of the KF/FeCI3 mix ture (KF: pentachloropyridine molar ratio 8:1). The reaction vessel was glass, and the contents were
heated at 340"C for 30 hours. There was obtained a
31 percent yield of 2,3,4,5 - tetrachloro - 6 - fluoropyridine, a 57 percent yield of 2,3, 5 - dichloro -4,6- difluoropyridine, and an 8 percent yield of 3,5 - dichloro - 2,4, 6 - trifluoro - pyridine.
Example 3
The method for this Example was similar to
Example 1 except as follows. The reaction mixture
contained 29 (0.008 mole) pentachloropyridine and
1.62g (0.028 mole KF) of the KFlFeCI3 mixture, and
the reactants were heated at 250"C. There was
obtained a 2 percent yield of 2,3,4, 5 - tetrachloro - 6
- fluoropyridine, 24 percent yield of 2, 3, 5 - dichloro 4, 6 - difluoropyridine and 61 percent yield of 3,5 dichloro - 2,4, 6 - trifluoropyridine.
Example 4 (Comparative)
Example 3 was repeated except that no catalyst
(FeCI3) was used. There was obtained 5 percent
unreacted pentachloropyridine, 38 percent yield of 2,
3,4, 5 - tetrachloro - 6 - fluoropyridine, 33 percent
yield of 2,3, 5 - trichloro - 4, 6 - difluoropyridine and 17 percent yield of3, 5 - dichloro - 2,4 - 6 - trif- luoropyridine.
Example 5
The method for this Example was similar to
Example 1 except as follows. The reaction mixture
contained 2g (0.0092 mole) 2,3, 5, 6 - tetrach
loropyridine and 1.629 (0.0276 mole KF) of the
KF/FeCI3 mixture. There was obtained 70 percent
yield of 3,5 - dichloro - 2,6 - difluoropyridine.
Example 6 (Comparative) Examples was repeated except that no catalyst
(FeCI3) was used. There was obtained 1 percent of
unreacted 2,3,5, 6-tetrachloropyridine, 22 percent
yield of 2,3,5 - trichloro - 6 - fluoropyridine and 61
percent yield of 3,5 5 - dichloro - 2,6 - dif
luoropyridine.
Claims (48)
1. A process for preparing a fluoropyridine compound, which process comprises reacting a chlorinated pyridine compound with a molar excess of an alkali metal fluoride in the presence of a catalytic amount of a catalyst selected from halides of organometals and halides of metals of the iron, nickel and copper groups, whereby the or at least one chlorine of the chlorinated pyridine compound is replaced by fluorine.
2. A process as claimed in claim 1, wherein the catalyst is a bromide or a chloride.
3. A process as claimed in claim 1 or claim 2, wherein the organometal is aluminium or antimony.
4. A process as claimed in claim 1, wherein the catalyst is SbCI3, AIR13, FeCI3 or ZnCI2.
5. A process as claimed in any one of the preceding claims, wherein the amount of alkali metal fluoride used is 10 to 50% in excess of the theoretical amount of fluorine required to produce the desired fluoropyridine.
6. A process as claimed in any one of the preceding claims wherein the catalyst is employed in an amount of from 1 to 3 percent by weight based on the amount of alkali metal fluoride.
7. A process as claimed in any one of the preceding claims wherein the alkali metal fluoride employed is KF.
8. A process as claimed in any one of the preceding claims, wherein the reaction is carried out in equipment in which the parts contacted by the reactants are constructed of material that is inert to alkali metal fluorides.
9. A process as claimed in claim 8, wherein the construction material is stainless steel or nickel.
10. A process as claimed in any one of the preceding claims, wherein the reaction is carried out in the absence of a solvent.
11. A process as claimed in any one of the preceding claims wherein the reaction is carried out at a temperature within the range of from 150 to 400"C.
12. A process as claimed in claim 11, wherein the reaction is carried out at a temperature within the range of from 250 to 350"C.
13. A process as claimed in any one of the preceding claims, wherein the chlorinated pyridine compound employed is pentachloropyridine.
14. A process as claimed in claim 13, wherein the principal product is 3, 5 - dichloro - 2,4,6 - trifluoropyridine.
15. A process as claimed in any one of the claims 1 to 12 wherein the chlorinated pyridine compound employed is 2,3, 5, 6 - tetrachloropyridine.
16. A process as claimed in claim 15, wherein the principal product is 3, 5 - dichloro - 2,6 - difluoropyridine.
17. A process as claimed in any one of claims 1 to 12, wherein the chlorinated pyridine compound employed is 2, 6 - dichloropyridine.
18. A process as claimed in claim 17 wherein the principal product is 2, 6 - difluoropyridine.
19. A process for preparing afluoropyridine compound, which process comprises reacting in a sealed inert vessel pentachloropyridine with from 3.3 to 4.5 moles of potassium fluoride per mole of the pentachloropyridine in the presence of from 1 to 3 percent by weight of FeCI3 based on the amount of potassium fluoride and in the absence of a solvent at a temperature within the range of from 250 to 350"C, and recovering 3, 5 - dichloro - 2,4,6 - trifluoropyridine as the principal product.
20. A process as claimed in claim 1 for preparing a fluoropyridine compound, which process is substantially as hereinbefore described in any one of the
Examples.
21. A fluoropyridine compound which has been prepared by a process as claimed in any one of the preceding claims.
22. 3, 5 - Dichloro - 2,4, 6 - trifluoropyridine which has been prepared by a process as claimed in claim 14 or claim 19.
23. 3, 5 - Dichloro - 2,6 - difluoropyridine which has been prepared by a process as claimed in claim 16.
24. 2, 6 - Difluoropyridine which has been prepared by a process as claimed in claim 18.
25. Afluoropyridine compound which has in the 4-position thereof an amino group and which has been prepared from a fluoropyridine as claimed in claim 21.
26. 4 - Amino - 3,5 - dichloro - 2,6 - difluoropyridine which has been prepared from 3, 5 dichloro - 2,4,6 - trifluoro - pyridine as claimed in claim 22.
27. A fluoropyridine compound which is a salt of a 2 - hydroxyfluoropyridine and which has been prepared from a fluoropyridine as claimed in claim 21 or claim 25.
28. A fluoropyridine compound as claimed in claim 27 which is the sodium salt of a 2 - hydroxyfluoropyridine.
29. A fluoropyridine compound which is a salt of 4 - amino - 3,5 - dichloro - 6 - fluoro - 2 - hydroxypyridine and which has been prepared from a fluoropyridine as claimed in claim 22 or claim 26.
30. Afluoropyridine compound as claimed in claim 29 which is the sodium salt of 4 - amino - 3, 5 dichloro - 6 - fluoro - 2 - hydroxypyridine.
31. A fluoropyridine compound which is agriculturally useful and which has been prepared from a fluoropyrydine compound as claimed in claim 21.
32. Afluoropyridine compound which isagricul- turally useful and which has been prepared from a fluoropyridine compound as claimed in any one of claims 22 to 30.
33. A fluoropyridine compound of general formula:
wherein each X independently represents, chloro, bromo or fluoro; R represents -CONR3R4 (where R3 and R4 independently each represents hydrogen or alkyl containing from 1 to 8 carbon atoms), -COOH or a salt thereof, or-COORS (where R5 represents alkyl containing from 1 to 12 carbon atoms or -(CH3)OR0whern n represents an integer of from 2 to 4 and RS represents lower alkyl or phenyl); and M represents hydrogen or lower alkyl, which fluoropyridine compound has been prepared from a fluoropyridine compound as claimed in claim 21.
34. A fluoropyridine compound of general formula (I) as defined in claim 33, which fluoropyridine compound has been prepared from a fluoropyridine compound as claimed in claim 25 or claim 27.
35. A fluoropyridine compound of general formula:
or a salt thereof, wherein R' represents hydrogen or an alkyl group having from 6 to 16 carbon atoms, which fluoropyridine compound has been prepared from a fluoropyridine compound as claimed in claim 21.
36. A fluoropyridine compound as claimed in claim 35 which is an amine salt.
37. A fluoropyridine compound of general formula (II) as defined in claim 35, which fluoropyridine compound has been prepared from a fluoropyridine compound as claimed in claim 25 or claim 27.
38. Afluoropyridine compound of formula:
which fluoropyridine compound has been prepared from a fluoropyridine compound as claimed in claim 21.
39. Afluoropyridine compound as claimed in claim 38 which has been prepared from a fluoropyridine compound as claimed in claim 23.
40. A fluoropyridine compound of formula:
which fluoropyridine compound has been prepared from a fluoropyridine compound as claimed in claim 21.
41. A fluoropyridine compound as claimed in claim 40 which has been prepared from a fluoropyridine compound as claimed in claim 24.
42. A agriculturally-useful composition compris
ing a fluoropyridine compound as claimed in claim 31 or claim 32.
43. A herbicidal composition comprising a fluoropyridine compound as claimed in claim 33 or claim 34.
44. A herbicidal composition comprising a fluoropyridine compound as claimed in any one of claims 35 to 37.
45. A herbicidal composition comprising a fluoropyridine compound as claimed in claim 38 or claim 39.
46. A nematocidal composition comprising a fluoropyridine compound as claimed in claim 40 or claim 41.
47. A method of inhibiting the growth of undesirable plants, which method comprises applying to said plants or their habitats a fluorpyridine compound as claimed in any one of claims 31 to 39 or a composition as claimed in any one of claims 42 to 45.
48. A method of protecting plants from attack by nematodes which method comprises applying to said plants or their habitats a fluoropyridine compound as claimed in claim 40 or claim 41 or a composition as claimed in claim 46.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7901122A GB2039473B (en) | 1979-01-11 | 1979-01-11 | Reaction of a chlorinated pyridine with an alkali metal fluoride |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7901122A GB2039473B (en) | 1979-01-11 | 1979-01-11 | Reaction of a chlorinated pyridine with an alkali metal fluoride |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2039473A true GB2039473A (en) | 1980-08-13 |
| GB2039473B GB2039473B (en) | 1983-05-05 |
Family
ID=10502472
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7901122A Expired GB2039473B (en) | 1979-01-11 | 1979-01-11 | Reaction of a chlorinated pyridine with an alkali metal fluoride |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2039473B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0178260A3 (en) * | 1984-10-10 | 1987-01-07 | Ciba-Geigy Ag | Process for the preparation of fluorinated pyridine derivatives |
| EP0354444A3 (en) * | 1988-08-12 | 1990-08-01 | Bayer Ag | Process for the introduction of fluorine on aromatic nucleus by nucleophilic exchange |
-
1979
- 1979-01-11 GB GB7901122A patent/GB2039473B/en not_active Expired
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0178260A3 (en) * | 1984-10-10 | 1987-01-07 | Ciba-Geigy Ag | Process for the preparation of fluorinated pyridine derivatives |
| US4831148A (en) * | 1984-10-10 | 1989-05-16 | Ciba-Geigy Corporation | Process for the preparation of fluorinated pyridine derivatives |
| EP0354444A3 (en) * | 1988-08-12 | 1990-08-01 | Bayer Ag | Process for the introduction of fluorine on aromatic nucleus by nucleophilic exchange |
| US4978769A (en) * | 1988-08-12 | 1990-12-18 | Bayer Aktiengesellschaft | Process for introducing fluorine atoms into aromatic rings by nucleophilic exchange |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2039473B (en) | 1983-05-05 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |