IL129109A - Process for the preparation of fluoroolefin compounds - Google Patents
Process for the preparation of fluoroolefin compoundsInfo
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- IL129109A IL129109A IL12910997A IL12910997A IL129109A IL 129109 A IL129109 A IL 129109A IL 12910997 A IL12910997 A IL 12910997A IL 12910997 A IL12910997 A IL 12910997A IL 129109 A IL129109 A IL 129109A
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- lithium
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- fluorophenyl
- fluorobenzeneboronate
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Abstract
A process for preparing a fluoroolefin compound of the formula wherein Ar is phenyl optionally substituted with any combination of from one to three halogen, C1-C4 alkyl, C1-C4 haloalkyl, C1-C4 alkoxy or C1-C4 haloalkoxy groups, or 1- or 2-naphthyl optionally substituted with any combination of from one to three halogen, C1-C4 alkyl, C1-C4 haloalkyl, C1-C4 alkoxy or C1-C4 haloalkoxy groups; R is hydrogen and R1 is cyclopropyl, or R and R1 are each independently C1-C4 alkyl, or R and R1 are taken together with the carbon atom to which they are attached to form a cyclopropyl group; and the configuration of the hydrogen atom and the fluorine atom about the double bond being mutually trans, which process comprises oxidizing 5-bromo-2-fluorobenzeneboronic acid to form 5-bromo-2-fluorophenol, first reacting 5-bromo-2-fluorophenyl phenyl ether, second reacting 5-bromo- 2-fluorophenyl phenyl ether with magnesium to form the corresponding magnesium bromide, and third reacting the magnesium bromide with a compound of the formula wherein Ar, R and R1 are as described above, and Q is OC(O)CH3 or Br, in the presence of a transition metal catalyst selected from the group consisting of a cuprous halide, cuprous cyanide and Li2CuCl4, wherein, prior to the oxidizing step, the improvement comprises lithiating 1-bromo-4-fluorobenzene with at least about one molar equivalent of a lithium base in the presence of a solvent to form (5-bromo-2-fluorophenyl) lithium, reacting (4-bromo-2-fluorophenyl) lithium with a tri (C1-C6 alkyl) borate to form a di(C1-C6 alkyl) 5-bromo-2-fluorobenzeneboronate, and hydrolyzing the di (C1-C6 alkyl) 5-bromo-2-fluorobenzeneboronate to form 5-bromo-2- fluorobenzeneboronic acid.
Description
A PROCESS FOR THE PREPARATION OF FLUOROOLEFIN COMPOUNDS PAT/4951 This application has been divided out of co-pending Application No.121066 ("The Parent Application"). 5-Eromo-2 -f luorobenzeneboronic acid is an important: intermediate in the synthesis of a number of non-ester pyrethroid compounds. 5 -Bromo-2-f luorobenzeneboronic acid and processes for its preparation are described in U.S. 5,068,403 and Pesticide Science, 23, PP- 25-34 (1950) , which are incorporated herein by reference.
These references disclose that 5-brcmo-2-flucrc- benzen.eboron.io acid is prepared from 2 , 4 -dibromof luoro- ce zene. However, 2 , 4 -dibromof luorobenzene is net entirely satisfactory for use in the commercial manufacture cf 5 -farorao-2-f luorobenzeneboronic acid. 2, -Dibromo luorobenzene is commercially available as a mixture containing seventy percent 2,4- dibrcciof luorobenzene and thirty percent 3,4- dibromof luorobenzene . When that mixture is used to prepare 5 -brgmo-2-f luorobenzeneboronic acid, at most, only a 70% yield is obtainable based on the total amount used. In addition, to obtain high purity 5-bromo-2- f luorobenzeneboronic acid, a time-consuming purification step is required to remove impurities such as 3,4 - dibromof luorobenzene . A process that avoids the use of 2 , 4 -dibromof luorobenzene would provide a great improvement over the art processes.
It is therefore an object of the invention of the parent application to provide a prccsss for the preparation of 5-bromo-2- f luorobenzeneboronic acid which avoids the use of 2,4- dibrcmof luorobenzene . The invention of the parent application process for the preparation of 5-brcmo-2- fluorobenzeneboronic acid which comprises lithiating 1-bromo-4 - fluorobenzene with a lithium base in the presence of a solvent to form ( 5 -bromo-2- fluorophenyl) lithium, reacting ( 5 -bromo-2 -fluorophenyl) lithium with a tri(Cx-Csalkyl) borate to form a di ) 5-bromo-2-fluorobenzeneboronate , and hydrolyzing the di (C1-C6alkyl) 5 -bromo-2 - fluorobenzeneboronate . It has been found that the process of this invention is more effective and efficient than the prior art processes, and avoids the use of 2 , 4 -dibromo- fluorobenzene which is commercially availably only as an impure mixture.
The present invention provides a process for the preparation of a fluoroolefin compound of formula I (0 wherein Ar is phenyl optionally substituted with any combination of from one to three halogen, C1-C4alkyi, C -Cjhaloalkyl , C1-C4alkoxy or C1-C4haloaikoxy groups, or 1- or 2-naphthyl optionally substituted with any combination of from one to three halogen, C1-C4haioalkoxy groups; R is hydrogen and Rx is cyclopropyl, or R and R-, are each independently C-C^aikyl, or R and R,_ are taken together with the carbon atom to which they are attached to form a cyclopropyl group.
The configuration of the hydrogen atom and the fluorine atom about the double bond is mutually trans. The process comprises lithiating 1 -bromo -4 - fluorobenzene with a lithium base in the presence of a solvent to form (5-bromo-2-fluorophenyl) lithium, reacting (5-bromo-2-fluorophenyl) lithium with a tri (Ci-C6alkyl) borate to form a di (Ci-Cgalkyl) 5-bromo-2-fluorobenzeneboronate, hydrolyzing the di (Ci-Cgalkyl) 5-bromo-2-fluorobenzeneboronate to form 5-bromo-2-fluorobenzeneboronic acid, oxidizing 5-bromo-2-fluorobenzeneboronic acid to form 5-bromo-2-fluorophenol , reacting 5-bromo-2-fluorophenol with bromobenzene and a base such as sodium hydride to form 5-bromo-2-fluorophenyl ether, reacting 5-bromo-2-fluorophenyl ether with magnesium, and reacting the resulting compound in the presence of a transition metal catalyst such as a cuprous halide, cuprous cyanide or Li2CuCl4 to form the desired fluoroolefin of formula I .
The fluoroolefin compound is useful in a pesticide composition .
The invention of the parent application and the present invention are described in the following specific embodiments : THE PARENT APPLICATION 1. A process for the preparation of 5-bromo-2-fluorobenzeneboronic acid which comprises lithiating 1-bromo-4-fluorobenzene with at least about one molar equivalent of a lithium base in the presence of a solvent to form (5-bromo-2-fluorophenyl) lithium, reacting (5-bromo-2-fluorophenyl) lithium with a tri (Ci-C6alkyl) borate to form a di (Cx-Cgalkyl) 5-bromo-2-fluorobenzeneboronate, and hydrolyzing the di (Ci-Cgalkyl) 5-bromo-2-fluorobenzeneboronate . 2. The process of embodiment 1 wherein l-bromo-4-fluoroben is lithiated with the lithium base at a temperature below about 0°C. 3. The process of embodiment 2 wherein the temperature is below about -40°C. 4. The process of embodiment 1 wherein the lithium base is lithium dialkylamide or a lithium cyclic amide. 5. The process of embodiment 4 wherein the lithium base is a lithium diisopropyl amide. 6. The process of embodiment 1 wherein the solvent is an an ether. 7. The process of embodiment 6 wherein the ether is tetrahydrofuran . 8. The process of embodiment 1 wherein the tri (Ci-C6alkyl) borate is trimethyl borate. 9. The process of embodiment 1 wherein the di (Ci-Cgalkyl) 5-bromo-2-fluorobenzeneboronate is hydrolyzed with an aqueous organic acid or an aqueous mineral acid. 10. A process for the preparation of 5-bromo-2-fluorobenzeneboronic acid which comprises lithiating 1-bromo-4-fluorobenzene with at least about one molar equivalent of a lithium base selected from the group consisting of a lithium dialkylamide and a lithium cyclic amide in the presence of an ether to form (5-bromo-2- fluorophenyl) lithium, reacting (5-bromo-2-fluorophenyl) lithium with a tri (Ci-C6alkyl) borate to form a di (Ci-C6alkyl) 5-bromo-2-fluorobenzeneboronate, and hydrolyzing the di Cx-Cgalkyl) 5-bromo-2-fluorobenzeneboronate with an aqueous organic acid or an aqueous mineral acid.
THE PRESENT APPLICATION This application relates to a process for preparing a fluoroolefin compound having the formula wherein Ar is phenyl optionally substituted with any combination of from one to three halogen, Ci~C alkyl, Ci~C4haloalkyl , Ci~C4alko y or Ci-C4haloalkoxy groups, or 1- or 2-naphthyl optionally substituted with any combination of from one to three halogen, Cx-C4alkyl, C1-C4 haloalkyl, C2~C alkoxy or C!-C4haloalkoxy groups; R is hydrogen and Ri is cyclopropyl, or R and Ri are each independently C2-C4alkyl, or R and Ri are taken together with the carbon atom to which they are attached to form a cyclopropyl group; and the configuration of the hydrogen atom and the fluorine, atom about the double bond is mutually trans . The process comprises lithiating l-bromo-4-fluorobenzene with a lithium base in the presence of a solvent to form (5-bromo-2-fluorophenyl) lithium, first reacting (5-bromo-2-fluorophenyl) lithium with a tri (Ci-Cg lkyl) borate to form a di (Ci-C6alkyl) 5-bromo-2-fluorobenzeneboronate , hydrolyzing the di (Ci-C6alkyl) 5-bromo-2- fluorobenzeneboronate to form 5-bromo-2- fluorobenzeneboronic acid, oxidizing 5-bromo-2-fluorobenzeneboronic acid to form 5-bromo-2- luorophenol , second reacting 5-bromo-2-fluorophenol with bromobenzene and a base to form 5-bromo-2- fluorophenyl ether, third reacting 5-bromo-2-fluorophenyl phenyl ether with magnesium to form the corresponding magnesium bromide, and fourth reacting the magnesium bromide with a compound having the formula wherein Ar, R and Ri are as described above and Q is OC (O) CH3 or Br in the presence of a transition metal catalyst.
This application also relates to the process described above wherein the base in the second reacting step is sodium hydride .
Passages appearing below may include material not relating to the present application and outside the scope of the claims . These passages are retained for completeness .
DETAILED DESCRIPTION OF THE INVENTION The process preferably comprises lithiating 1-bromo-4-fluorobenzene with at least about one molar equivalent of a lithium base in the presence of a solvent preferably at a temperature below about 0°C, more preferably below about -40°C, to form (5-bromo-2-fluorophenyl) lithium, reacting (5-bromo-2-fluorophenyl) lithium with at least about one molar equivalent of a tri (Ci-Cg lkyl) borate to form a di (Ci-Cgalkyl) 5-bromo-2-fluorobenzeneboronate, and hydrolyzing the di (Ci-C6alkyl) 5-bromo-2-fluorobenzene boronate with at least about two molar equivalents of an aqueous acid to form the desired 5-bromo-2-fluorobenzene-boronic acid. The reaction scheme is shown in Flow Diagram I .
FLOW DIAGRAM I Br Advantageously, the process of this invention overcomes the problems associated with the use of impure 2 , 4 -dibromofluorobenzene by using 1 -bromo-4 - fluoroben-zene. By avoiding the use of impure 2 , 4 -dibromofiuoro-benzene, the process of this invention provides 5-bromo-2 - fluorobenzeneboronic acid in higher yield and higher purity than the less effective and less efficient art processes .
Lithium bases suitable for use in the process of this invention include lithium secondary amide bases such as lithium dialkylamides , lithium cyclic amides, lithium arylalkylamides and lithium bis (alkylsilyl ) amides and alkyl lithiums such as n-butyl lithium, s-butyl lithium, and tert -butyl lithium. Preferred lithium bases include lithium diaikyiamides such as lithium diisopropylamide and lithium isopropylcyclohexylamide , lithium cyclic amides such as lithium 2 , 2 , 6 , 6 - etramethylpiperidine , lithium arylalkylamides such as lithium phenylmethyl -amide, and bis (alkylsilyl ) amides such as lithium bis (trimethylsilyl ) amide , with lithium diisopropylamide and lithium 2 , 2 , 6 , 6-tetramethylpiperidine being more preferred .
Solvents suitable for use in the process of the present invention include organic solvents which do not react: undesirably with any of the compounds present in the reaction mixture. Preferred organic solvents include ethers such as cecrahydrofuran, diethyl ether, 1,2-di-methoxyethane, and mixtures thereof, with tetrahydrofuran being more preferred.
Preferred cri borates include trimethyl borate, triethyl borate, tri-n-butyl borate and triiso-propyi borate with trimethyl borate being more preferred.
The di (C:-C£alkyl ) 5-bromo-2-fluorobenzeneboronate compound is preferably hydrolyzed with an aqueous organic acid such as acetic acid, propionic acid and butyric acid or an aqueous mineral acid such as hydrochloric acid and sulfuric acid.
In order to facilitate a further understanding of the invention, the following example is presented to illustrate more specific details thereof. The invention is not to be limited thereby except as defined in the claims .
EXAMPLE 1 Preparation of 5-Bromo-2-fluorobenzeneboronic acid A solution cf lithium diisopropylamide (165 mL of a 2.0 solution in tetrahydrofuran , 0.33 mol) in tetrahy-drofuran (600 mL) at -70 °C is treated with l-bromo-4-fluorobenzene (33.0 mL, 0.30 mol), stirred at -70 °C for 90 minutes and added to a solution of trimethyl borate (41.0 mL, 0.36 mcl) in diethyl ether (300 mL) at -70 °C. The resulting solution is stirred at -70 °C for 15 minutes, warmed to 15 °C over 90 minutes, treated with acetic acid (51.5 mL. 0.9 mol) and water (375 mL) , and stirred at room temperature for 30 minutes. The organic layer _is separated and the aqueous layer is extracted with ether. The organic extracts are combined with the organic layer and the resulting solution is washed seauentially with 10% hydrochloric acid and brine, dried over anhydrous magnesium sulfate and concentrated in vacuo to give the title product as an off-white solid (65 g, 99% yield) .
Advantageously, the present invention also provides a process for the preparation of a fluoroolefin compound of formula I (I) wherein Ar is phenyl optionally substituted with any combination of from one to three halogen, C^Calkyi, C^-Chaloalkyl , C^-C^alkoxy or -C^haloalkoxy groups, or 1- or 2-naphthyl optionally substituted with any combination of from one tc three halogen, -Cjalkyl, C:-C4haloalkyl, C^C.alkoxy or (^-dhaloalkoxy groups; R is hydrogen and Rx is cyclopropyl, or R and R, are each independently -C.alkyl, or R and R,_ are taken together with the carbon atom to which they are attached to form a cyclopropyl group; and the configuration of the hydrogen atom and the fluorine atom about the double bond is mutually trans.
The process comprises lithiating l-bromo-4-fluorobenzene with a lithium base in the presence of a solvent to form ( 5 -bromo-2- fluorophenyl) lithium, reacting C5-bromo-2-fluorophenyl) lithium with a tri (Ci -C6alkyl ) borate to form a di (C1-C6alkyl } 5-bromo-2-fImorobenzeneboronate , hydrolyzing the di (C-, -C6alkyl) 5-bromo-2- luorobenzeneboronate to form 5 -bromo-2 - luorobenzeneboronic acid, oxidizing 5-bromo-2-fliioroberizenebcronic acid to form 5 -bromo-2 - fluorophenol , reaccln<~ 5 -bromo-2 -fluorophenol with bromobenzene and a base such as a sodium hydride to form 5 -bromo-2 -fluorophenyl ether, reacting 5 -bromo-2- fluorophenyl phenyl ether with magnesium to form a magnesium bromide of formula II, and reacting the formula II compound with an alkene compound of formula III in the presence of a transition metal catalyst sych as cuprous halide, cuprous cyanide or Li:CuCl4 to form the desired fluoroolefin of formula I. The fluoroolefin compound is useful in a pesticide composition .
The reaction scheme for the preparation of the fluoroolefin compound is shown in Flow Diagram II.
FLOW DIAGRAM II Br I Lithium Base i B[0{C_-C6alkyI) ] ĨI)
Claims (11)
1. In a process for preparing a fluoroolefin compound having the formula H wherein Ar is phenyl optionally substituted with any combination of from one to three halogen, Ci-^alkyl, Ci-C4haloalkyl , Ci-C4alkoxy or Ci-C4haloalkoxy groups, or 1- or 2-naphthyl optionally substituted with any combination of from one to three halogen, Ci-C4alkyl, Ci-C4haloalkyl , Ci~C4alkoxy or Ci~C4haloalkoxy groups; R is hydrogen and Ri is cyclopropyl, or R and Ri are each independently Ci-C4alkyl, or R and Ri are taken together with the carbon atom to which they are attached to form a cyclopropyl group; and the configuration of the hydrogen atom and the fluorine atom about the double bond being mutually trans, which process comprises oxidizing 5-bromo-2-fluorobenzeneboronic acid to form 5-bromo-2-fluorophenol , first reacting 5-bromo-2-fluorophenol with bromobenzene and a base to form 5-bromo-2-fluorophenyl phenyl ether, second reacting 5-bromo-2-fluorophenyl phenyl ether with magnesium to form the corresponding magnesium bromide, and 129109/2 16 third reacting the magnesium bromide with a compound having the structural formula H wherein Ar, R and Ri are as described above, and Q is OC(0)CH3 or Br, in the presence of a transition metal catalyst selected from the group consisting of a cuprous halide, cuprous cyanide and Li2CuCl , wherein, prior to the oxidizing step, the improvement comprises lithiating l-bromo-4-fluorobenzene with at least about one molar equivalent of a lithium base in the presence of a solvent to form (5-bromo-2- fluorophenyl) lithium, reacting (5-bromo-2-fluorophenyl) lithium with a tri (Ci~ C6alkyl) borate to form a di (Ci-C6alkyl) 5-bromo- 2-fluorobenzeneboronate, and hydrolyzing the di (Ci-C6alkyl) 5-bromo-2- fluorobenzeneboronate to form 5-bromo-2- fluorobenzeneboronic acid.
2. In a process for preparing a fluoroolefin compound having the formula H 129109 17 wherein Ar is phenyl optionally substituted with any combination of from one to three halogen, Ci-C4alkyl , Ci-C4haloalkyl , Ci-C4alkoxy or Ci-C4haloalkoxy groups, or 1- or 2-naphthyl optionally substituted with any combination of from one to three halogen, Ci-C4alkyl, Ci-C4haloalkyl , Ci~C4alkoxy or Ci-C4haloalkoxy groups; R is hydrogen and Ri is cyclopropyl , or R and Rj. are each independently Ci-C4alkyl, or R and Ri are taken together with the carbon atom to which they are attached to form a cyclopropyl group; and the configuration of the hydrogen atom and the fluorine atom about the double bond being mutually trans, which process comprises oxidizing 5-bromo-2-fluorobenzeneboronic acid to form 5- bromo-2-fluorophenol , first reacting 5-bromo-2-fluorophenol with bromobenzene and a base to form 5-bromo-2-fluorophenyl phenyl ether, second reacting 5-bromo-2-fluorophenyl phenyl ether with magnesium to form the corresponding magnesium bromide, and third reacting the magnesium bromide with a compound having the structural formula H 129109 18 wherein Ar, R and Ri are as described above, and Q is OC(0)CH3 or Br, in the presence of a transition metal catalyst selected from the group consisting of a cuprous halide, cuprous cyanide and Li2CuCl4, wherein, prior to the oxidizing step, the improvement comprises lithiating l-bromo-4-fluorobenzene with at least about one molar equivalent of a lithium base selected from the group consisting of a lithium dialkylamide and a lithium cyclic amide in the presence of an ether to form (5-bromo-2- fluorophenyl) lithium, reacting (5-bromo-2-fluorophenyl) lithium with a tri (Ci- C6alkyl) borate to form a di (Ci-C6alkyl) 5-bromo- 2-fluorobenzeneboronate, and hydrolyzing the di (Ci-C6alkyl) 5-bromo-2- fluorobenzeneboronate with an aqueous organic acid or an aqueous mineral acid to form 5-bromo- 2-fluorobenzeneboronic acid.
3. The process of claim 1 wherein the base in the first reacting step is sodium hydride.
4. The process of claim 1 or 2 wherein l-bromo-4- luorobenzene is lithiated with the lithium base at temperature below about 0°C.
5. The process of claim 4 wherein the temperature is below about - 0°C.
6. The process of claim 1 or 2 wherein the lithium base is a lithium dialkylamide or a lithium cyclic amide. 129109 19
7. The process of claim 6 wherein the lithium base is lithium diisopropyl amide.
8. The process of claim 1 or 2 wherein the solvent is an ether .
9. The process according to claim 8 wherein the ether is tetrahydro uran .
10. The process according to claim 1 or 2 wherein the tri (Ci~ Cealkyl) borate is trimethyl borate.
11. The process according to claim 1 or 2 wherein the di (Ci~ Cealkyl) 5-bromo-2-fluorobenzeneboronate is hydrolyzed with an aqueous organic acid or an aqueous mineral acid. OWITZ & CO. AGEN THE A .NT
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US66375596A | 1996-06-14 | 1996-06-14 | |
| IL12106697A IL121066A (en) | 1996-06-14 | 1997-06-12 | Process for the preparation of 5-bromo-2-fluorobenzeneboronic acid |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| IL129109A true IL129109A (en) | 2004-09-27 |
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Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| IL12910997A IL129109A (en) | 1996-06-14 | 1997-06-12 | Process for the preparation of fluoroolefin compounds |
| IL12910999A IL129109A0 (en) | 1996-06-14 | 1999-03-22 | A process for the preparation of fluoroolefin compounds |
Family Applications After (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| IL12910999A IL129109A0 (en) | 1996-06-14 | 1999-03-22 | A process for the preparation of fluoroolefin compounds |
Country Status (1)
| Country | Link |
|---|---|
| IL (2) | IL129109A (en) |
-
1997
- 1997-06-12 IL IL12910997A patent/IL129109A/en not_active IP Right Cessation
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1999
- 1999-03-22 IL IL12910999A patent/IL129109A0/en unknown
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| Publication number | Publication date |
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| IL129109A0 (en) | 2000-02-17 |
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