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Title:
METHOD FOR PRODUCING 2-HALOGENOMETHYLPHENYL ACETIC ACID DERIVATIVES
Document Type and Number:
WIPO Patent Application WO/2010/089267
Kind Code:
A2
Abstract:
The present invention relates to a process for producing 2-halogenomethylphenyl acetic acid derivatives.

Inventors:
KORTE, Alexander (Maximilianstraße 21, Neustadt, 67433, DE)
KEARNS, Mark Alan (13117 Trouville Court, Wake Forest, NC, 27587, US)
SMITH, Jonathan O. (2837 Cheswick Road, Quincy, IL, 62301, US)
LIPOWSKY, Gunter (Schillerstraße 8, Ladenburg, 68526, DE)
BIECHE, Willi (Raiffeisenstr. 48, Erpolzheim, 67167, DE)
Application Number:
EP2010/051144
Publication Date:
August 12, 2010
Filing Date:
February 01, 2010
Export Citation:
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Assignee:
BASF SE (67056 Ludwigshafen, DE)
KORTE, Alexander (Maximilianstraße 21, Neustadt, 67433, DE)
KEARNS, Mark Alan (13117 Trouville Court, Wake Forest, NC, 27587, US)
SMITH, Jonathan O. (2837 Cheswick Road, Quincy, IL, 62301, US)
LIPOWSKY, Gunter (Schillerstraße 8, Ladenburg, 68526, DE)
BIECHE, Willi (Raiffeisenstr. 48, Erpolzheim, 67167, DE)
International Classes:
C07C249/12; C07C251/38
Domestic Patent References:
1993-04-15
1995-12-21
1997-12-24
2003-09-04
2007-01-04
2001-06-14
2001-06-14
1996-05-30
1997-12-24
1993-04-15
1997-05-01
2008-10-23
Foreign References:
EP0398692A21990-11-22
CN101205187A2008-06-25
CN101139308A2008-03-12
DE10007695A12001-08-23
DE19959066C12001-05-03
EP0676389A21995-10-11
EP0619300A21994-10-12
EP0493711A11992-07-08
EP0254426A21988-01-27
EP0253213A11988-01-20
DE19508573A11996-03-14
CN1793115A2006-06-28
Other References:
AHMAD IJAZ ET AL: "A convenient entry into the rhoeadan skeleton. Total synthesis of (-+)-cis-alpinigenine", CANADIAN JOURNAL CHEMISTRY, vol. 60, no. 21, 1982, pages 2678-2686, XP002535580,
'The Pesticide Manual', 2006, THE BRITISH CROP PRODUCTION COUNCIL
Attorney, Agent or Firm:
BASF SE (67056 Ludwigshafen, DE)
Download PDF:
Claims:
Claims

1. Process for producing 2-halogenomethylphenyl acetic acid derivatives of formula

wherein X is chlorine or bromine, R1 is methyl, ethyl, n-propyl or i-propyl; and R2 is hydrogen, methyl or ethyl; said process comprising cleavage of an alkyloxime of formula

(II), wherein

R2 is methyl or ethyl; in the presence of an alcohol of formula

R1-OH (III),

wherein R1 is defined above; and a halogenating agent selected from the group consisting of thionyl halide, oxalyl halides and mixtures of thionyl bromide and hydrobromic acid, mixtures of thionyl chloride and hydrochloric acid or mixtures of oxalyl chloride and hydrochloric acid and mixtures of oxalyl bromide and hydrobromic acid.

2. A process according to claim 1 , wherein R1 is methyl or ethyl.

3. A process according to claim 1 or 2, wherein the halogenating agent is thionyl halide.

4. A process according to claim 1 or 2, wherein the halogenating agent is a mixture of thionyl chloride and hydrochloric acid or thionyl bromide and hydrobromic acid.

5. A process for the production of an alkyloxime of formula II, wherein R2 is methyl or ethyl, said process comprising reacting an oxime of formula IV

with an alkylating agent and a base in an inert organic solvent, wherein the inert organic solvent is toluene.

6. A process according to claim 1 , 2, 3 or 4, further comprising a process according to claim 5 for reacting an oxime of formula IV to an alkyl oxime of formula II.

7. A process for the production of an oxime of formula IV, said process comprising

a) reacting 3-isochromanone of formula V

with a nitrosating agent in presence of an alcohol and a base; and b) after completion of the reaction adjusting the pH to a pH <3.

8. A process according to claim 1 , 2, 3 or 4, further comprising a process according to claim 7 for reacting 3-isochromanone of formula V to an oxime of formula IV.

9. Use of 3-isochromanone of formula V for the production of 2- halogenomethylphenyl acetic acid derivatives of formula I.

10. Use according to claim 9, which includes cleavage of an alkyloxime of formula Il

wherein

R2 is methyl or ethyl; in the presence of an alcohol of formula III

R1-OH (III), wherein R1 is R1 is methyl, ethyl, n-propyl or i-propyl; and a halogenating agent selected from the group consisting of thionyl halide, oxa- IyI halides and mixtures of thionyl bromide and hydrobromic acid, mixtures of thionyl chloride and hydrochloric acid or mixtures of oxalyl chloride and hydrochloric acid and mixtures of oxalyl bromide and hydrobromic acid.

1 1. Process for producing 2-halogenomethylphenyl acetic acid derivatives of formula I, wherein R2 is methyl or ethyl comprising reaction of a compound of formula I, wherein R2 is hydrogen with an alkylating agent in an inert organic solvent.

12. A process for the production of 2-halogenomethylphenyl acetic acid derivatives of formula I, said method comprising

a) reacting a compound of formula V with a nitrosating agent according to claim 7, alkylation of the resulting oxime of formula IV as defined in claim 5 and cleavage of the obtained alkyloxime of formula Il as defined in claims 1 to 4, or

b) reacting a compound of formula V with a nitrosating agent as defined in claim 7, cleavage of the obtained oxime of formula IV of claim 5 according to the method set forth in claim 1 to 4, and subsequent alkylation of the resulting 2-halogenomethylphenyl acetic acid derivatives of formula I of claim 1 , wherein R2 is hydrogen, to the 2-halogenomethylphenyl acetic acid derivatives of formula I of claim 1 , wherein R2 is ethyl or methyl.

13. A process for the production of a strobilurine fungicide selected from the group consisting of dimoxystrobin, trifloxystrobin, kresoxim-methyl, orysastrobin, said process comprising

(1 a) cleavage of an alkyloxime of formula Il

(II), wherein

R2 is methyl or ethyl; in the presence of an alcohol of formula III

R1-OH wherein R1 is is methyl, ethyl, n-propyl or i-propyl; and a halogenating agent selected from the group consisting of thionyl halide, oxalyl halides and mixtures of thionyl bromide and hydrobromic acid, mixtures of thionyl chloride and hydrochloric acid or mixtures of oxalyl chloride and hydrochloric acid and mixtures of oxalyl bromide and hydrobromic acid; or

(1 b) cleavage of an alkyloxime of formula Il

(II), wherein

R2 is hydrogen in the presence of an alcohol of formula III

R1-OH

wherein R1 is is methyl, ethyl, n-propyl or i-propyl; and a halogenating agent selected from the group consisting of thionyl halide, oxalyl halides and mixtures of thionyl bromide and hydrobromic acid, mixtures of thionyl chloride and hydrochloric acid or mixtures of oxalyl chloride and hydrochloric acid and mixtures of oxalyl bromide and hydrobromic acid; followed by alklation of the resulting 2-halogenomethylphenyl acetic acid derivatives;

(2) reacting the resulting 2-halogenomethylphenyl acetic acid derivatives to the strobilurine.

Description:
Method for producing 2-halogenomethylphenyl acetic acid derivatives

The present invention relates to a process for producing 2-halogenomethylphenyl acetic acid derivatives of formula I

wherein X is chlorine or bromine;

R 2 is hydrogen, methyl or ethyl; and

R 1 is methyl, ethyl, i-propyl or n-propyl; said process comprising cleavage of an alky- loxime of formula Il

wherein R 2 is methyl or ethyl in the presence of an alcohol of formula III

R 1 -OH (III), wherein R 1 is methyl, ethyl, i-propyl or n-propyl; and a halogenating agent selected from the group consisting of thionyl halide, oxalyl halide and mixtures of thionyl bromide and hydrobromic acid, mixtures of thionyl chloride and hydrochloric acid or mixtures of oxalyl chloride and hydrochloric acid and mixtures of oxalyl bromide and hydrobromic acid.

2-Halogenomethylphenyl acetic acid derivatives are important intermediates for the preparation of agrochemically active compounds or microbiocides, e.g. in strobilurine synthesis. For example, the strobilurines dimoxystrobin, trifloxystrobin, kresoxim-methyl and orysastrobin can be easily produced by using these compounds.

The terms "dimoxystrobin", "trifloxystrobin", "kresoxim-methyl" and "orysastrobin" are the ISO names of certain agrochemically active compounds or microbiocides, analogously to INN names of pharmaceutically active substances. The ISO names designate unambigously a compound with a certain structure. The ISO names of the compounds, their structure and their IUPAC names respectively CAS names can be found e.g. on htt9://w>Λw.alanwood.net/p_esticides/, or in "The Pesticide Manual", 14 th Edition, 2006 The British Crop Production Council. The respective substance can be on the market under a variety of trademark names.

Furthermore, 2-halogenomethylphenyl acetic acid derivatives can be also used as intermediates in the syntheses of substituted p-trifluoromethyl phenyl ethers, which are compounds with insecticidal activity (WO 2007/000098 A1 and CN 101205187 A).

Currently published methods for the production of 2-halogenomethylphenyl acetic acid derivatives describe a route based on phthalides of formula A

(an overview is given in CN 101 139308, details for the respective single steps of the synthesis are, for example disclosed in DE 10007695 A, DE 19959066, WO 01/42182, WO 01/42185, EP 0676389 A, EP 0619300 A, WO 96/16023, EP 0493711A, EP 254 426 A and EP 253213 A). The synthesis contains a ring-opening step of the phthalide of formula A with thionyl chloride at temperatures >100 0 C followed by a reaction with toxic sodium cyanide.

Object of the present invention was to provide an efficient and/or short production route suitable for large scale synthesis, especially a production route to 2- halogenomethylphenyl acetic acid derivatives.

Further object of the present invention was to provide a production route, which can be based on educts (starting materials), which are less toxic than those used in currently existing routes.

The object was solved by a process for producing 2-halogenomethylphenyl acetic acid derivatives of formula I, which is based on 3-isochromanone.

Isochromanone-based syntheses for 2-(chloro- or bromomethyl)phenylacetates, which may serve as intermediates for agrochemicals, is mentioned in the art (see WO 97/48671). However, the processes described therein do not disclose the specific process of the present invention.

WO 93/07116 describes an isochromanone based synthesis of 2-hydroxymethylphenyl acetic acid derivatives.

The present invention relates to a process for producing 2-halogenomethylphenyl acetic acid derivatives of formula I

wherein X is chlorine or bromine; R 2 is hydrogen, methyl or ethyl; and R 1 is methyl, ethyl, i-propyl or n-propyl; said process comprising cleavage of an alky- loxime of formula Il

wherein R 2 is hydrogen, methyl or ethyl; in the presence of an alcohol of formula III R 1 -OH (III), wherein R 1 is methyl, ethyl, i-propyl or n-propyl; and a halogenating agent selected from the group consisting of thionyl halide, oxalyl halides and mixtures of thionyl bromide and hydrobromic acid, mixtures of thionyl chloride and hydrochloric acid or mixtures of oxalyl chloride and hydrochloric acid and mixtures of oxalyl bromide and hy- drobromic acid.

The term i-propyl is understood to be identical to iso-propyl (-CHMe 2 ). N-propyl is understood to be the linear propyl radical group.

The compound of formula I is a mixture of E/Z isomers. Preferably, the E isomer is present > 85% E isomer and < 15% Z isomer, more preferably > 90% E isomer and < 10% Z isomer, most preferably > 95% E isomer and <5% Z isomer.

Preferably, R 1 is methyl or ethyl, more preferably methyl. Preferably, X is chlorine.

Preferably, R 2 methyl or ethyl, more preferably methyl.

Particular preference is given to compounds of formula I listed in table I

In this subset, compounds 1-1 , I-2, I-3 and I-4 are preferred, and 1-1 and 1-2 are most preferred.

To achieve the preferred combinations, the skilled artisan will use the respective educts (starting materials) as outlined below.

Suitable thionyl halides are, for example thionyl chloride or thionyl bromide. Suitable oxalyl halides are oxalyl chloride or oxalyl bromide. Suitable mixtures are mixtures of thionyl chloride and hydrochloric acid, thionyl bromide and hydrobromic acid, oxalyl chloride and hydrochloric acid, oxalyl bromide and hydro- bromic acid.

The ratio of thionyl halide (or oxalyl halides) and respective acid is 1000:1 to 1 :10, preferably 1 :1 to 1 :10, more preferably 1 :3 to 1 :5.

Preferred halogenating agents are thionyl halide or a mixture of thionyl halide and hydrochloric or hydrobromic acid.

For chlorination, thionyl chloride or a mixture of thionyl chloride and hydrochloric acid is preferred. For bromination, thionyl bromide or a mixture of thionyl bromide and hydrobromic acid is preferred.

If the halogenating agent is thionyl halide or an oxalyl halide the molar ratio of compound of formula Il and the halogenating agent is preferably 1 :1 to 1 :20, more prefera- bly 1 :3 to 1 :15, most preferably 1 :5 to 1 :10.

If a mixture of thionyl halide (or oxalyl halide) and respective acid is used, the molar ratio of compound of formula Il and thionyl halide (or oxalyl halides) is 1 :1 to 1 :20, more preferably 1 :3 to 1 :15, most preferably 1 :3 to 1 :5.

Preferably, the molar ratio of the compound of formula Il and the alcohol is 1 :10 to 1 :100, preferably 1 :10 to 1 :60, more preferably 1 :20 to 1 :50. Optionally, the reaction mixture can further comprise an inert organic solvent. Useful solvents include aromatic (halogenated) hydrocarbons, e.g. benzene, toluene, xylene, chlorobenzene, dichlorobenzene, bromobenzene and benzotrifluoride; aliphatic (halogenated) hydrocarbons, e.g. pentane, heptane, dichloromethane, chloroform, 1 ,2- dichloroethane and carbon tetrachloride; cycloaliphatic hydrocarbons, e.g. cyclohexane and cyclopentane; ethers, e.g. dimethoxyethane, diethyl ether and di-isopropyl ether; esters, e.g. ethyl acetate and butyl acetate and polar aprotic solvents such as dimethyl- formamide, N-methylpyrrolidone, dimethylsulfoxide. Also mixtures of these solvents may be used. Preferred solvents include aromatic (halogenated) hydrocarbons, e.g. benzene, toluene, xylene, chlorobenzene and dichlorobenzene; aliphatic (halogenated) hydrocarbons such as e.g. dichloromethane, chloroform, 1 ,2-dichloroethane and carbon tetrachloride and polar aprotic solvents such as dimethylformamide, N- methylpyrrolidone. Also mixtures of these solvents may be used.

The reaction pressure is customarily from 0 to 100 bar. Preference is given to carrying out the reaction under atmospheric pressure. If the reaction is carried out under ato- mospheric pressure, the reaction temperature is customarily from -20 to 100 0 C, preferably from -10 to 40 0 C, more preferably from -10 to 30°C.

The compounds of formula II, wherein R 2 is methyl or ethyl, can be obtained by reacting an oxime of formula IV

according to methods known in the art, for example with an alkylating agent and a base in an inert organic solvent.

Suitable alkylating agents are widely known to the skilled artisan. Examples of suitable alkylating agents are dimethylsulfate, methyliodide, methylbromide, methylchloride, diazomethane and diethyl sulfate, ethyliodide, ethylbromide, ethylchlorid. Preferred alkylating agents are dimethylsulfate and methyliodide, more preferably dimethylsulfate.

Suitable bases are widely known to the skilled artisan. Examples of suitable bases include, but are not limited to potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide. Preferred bases are potassium carbonate and sodium car- bonate, more preferably potassium carbonate. Useful solvents include aromatic (halogenated) hydrocarbons, e.g. benzene, toluene, xylene, chlorobenzene, dichlorobenzene, bromobenzene and benzotrifluoride; aliphatic (halogenated) hydrocarbons, e.g. pentane, heptane, dichloromethane, chloroform, 1 ,2-dichloroethane and carbon tetra- chloride; cycloaliphatic hydrocarbons, e.g. cyclohexane and cyclopentane; ethers, e.g. dimethoxyethane, diethyl ether and di-isopropyl ether; esters, e.g. ethyl acetate and butyl acetate and polar aprotic solvents such as dimethylformamide, N- methylpyrrolidone, dimethylsulfoxide. Also mixtures of these solvents may be used. Preferred solvents include aromatic (halogenated) hydrocarbons, e.g. benzene, toluene, xylene, chlorobenzene and dichlorobenzene; aliphatic (halogenated) hydrocarbons such as e.g. dichloromethane, chloroform, 1 ,2-dichloroethane and carbon tetrachloride and polar aprotic solvents such as dimethylformamide, N-methylpyrrolidone. Also mixtures of these solvents may be used. To achieve high yields, it is preferred to use toluene as solvent.

The reaction pressure is customarily from 0 to 6 bar. Preference is given to carrying out the reaction under atmospheric pressure. If the reaction is carried out under atomos- pheric pressure, the reaction temperature is customarily from 0 to 100 0 C, preferably from 0 to 40 0 C, more preferably from 5 to 25°C.

The invention comprises also a process for producing 2-halogenomethylphenyl acetic acid derivatives of formula I as described herein, wherein X is chlorine or bromine; R 2 is hydrogen, methyl or ethyl; and

R 1 is methyl, ethyl, i-propyl or n-propyl; said process comprising cleavage of an alkyloxime of formula II, wherein R 2 is methyl or ethyl, in the presence of an alcohol R 1 -OH of formula III, wherein R 1 is methyl, ethyl, i- propyl or n-propyl, and a halogenating agent selected from the group consisting of thionyl halide, oxalyl halide and mixtures of thionyl bromide and hydrobromic acid, mixtures of thionyl chloride and hydrochloric acid or mixtures of oxalyl chloride and hydrochloric acid and mixtures of oxalyl bromide and hydrobromic acid, further comprising a process as described herein for reacting an oxime of formula IV to an alkyl oxime of formula II, in which the compounds of formula II, wherein R 2 is methyl or ethyl, are obtained by reacting an oxime of formula IV with an alkylating agent and a base in an inert organic solvent, wherein the inert organic solvent is preferably toluene.

The compounds of formula IV can be obtained by a process comprising

a) reacting 3-isochromanone of formula V

with a nitrosating agent in presence of an alcohol and a base,

b) after completion of the reaction adjusting the pH to a pH < 3, preferably pH < 1.

Preferred alcohols are methanol, ethanol, propanol or i-propanol more preferably methanol or ethanol, most preferably methanol.

Suitable bases include, but are not limited to alcoholates. Preferred alcoholates are

Na + , Li + or K + alcoholates, preferably the corresponding Na + or K + alcoholates, most preferably Na + alcoholates.

More preferably, the alcoholate corresponds to the alcohol, preferred embodiments are

Na + or K + CH 3 O-/ HOCH 3

Na + or K + CH 3 CH 2 O " / HO CH 2 CH 3

Na + or K + CH 3 CH 2 CH 2 OV HO CH 2 CH 2 CH 3 Na + or K + (CHs) 2 CH 2 OV HOCH 2 (CHs) 2 more preferably

Na + or K + CH 3 OV HOCH 3

Na + or K + CH 3 CH 2 OV HO CH 2 CH 3 most preferably Na + or K + CH 3 OV HOCH 3 utmost preferably

Na + CH 3 OV HOCH 3

The pH adjustment is made by a suitable acid with a pK a <0, preferably with a suitable mineral acid (e.g. hydrochloric acid, hydrobromic acid, sulfuric acid), more preferably with hydrochloric acid.

Suitable nitrosating agents are for example alkyl nitrites such as n-butyl nitrite, tert- butyl nitrite, iso-butyl nitrite, n-pentyl nitrite and iso-pentyl nitrite.

The reaction pressure is customarily from O to 6 bar. Preference is given to carrying out the reaction under atmospheric pressure. If the reaction is carried out under atmospheric pressure, the reaction temperature is customarily from O to 10O 0 C, preferably from 10 to 40 0 C, more preferably from 15 to 30°C.

The invention comprises also a process for producing 2-halogenomethylphenyl acetic acid derivatives of formula I as described herein, wherein X is chlorine or bromine;

R 2 is hydrogen, methyl or ethyl; and

R 1 is methyl, ethyl, i-propyl or n-propyl; said process comprising cleavage of an alkyloxime of formula II, wherein R 2 is methyl or ethyl, in the presence of an alcohol R 1 -OH of formula III, wherein R 1 is methyl, ethyl, i- propyl or n-propyl, and a halogenating agent selected from the group consisting of thionyl halide, oxalyl halide and mixtures of thionyl bromide and hydrobromic acid, mixtures of thionyl chloride and hydrochloric acid or mixtures of oxalyl chloride and hydrochloric acid and mixtures of oxalyl bromide and hydrobromic acid, further comprising a process as described herein for reacting 3-isochromanone of formula V to an oxime of formula IV, in which a) 3-isochromanone of formula V is reacted with a nitrosating agent in presence of an alcohol and a base, and b) after completion of the reaction the pH is adjusted to a pH < 3, preferably pH < 1.

The present invention also comprises the use of 3-isochromanone of formula V for the production of 2-halogenomethylphenyl acetic acid derivatives of formula I. The gist of the invention is the provision of a synthesis route to compounds of formula I as defined herein (i.e. having a methoxyimino group), starting from 3-isochromanone of formula V.

WO 97/48671 discloses the cleavage of 3-isochromanone of formula V to 2- halogenomethylphenyl acetic acid derivatives of formula I':

The compounds of formula I' disclosed in WO 97/48671 lack the methoxyimino group which is characteristic for the compounds of formula I according to the present invention. Although WO 97/48671 claims that the compounds of formula I' would be suitable for the synthesis of strobilurin type fungicides, for which a generic formula is given, WO 97/48671 fails to disclose how the methoxyimino group may be introduced into the compound.

If compounds of formula I' are subjected to the oximation step, this does not lead to the desired oxime product in sufficient yield, but only a complex mixture is obtained, mak- ing it impossible to proceed with the alkylation step. WO 97/48671 does therefore not put the person skilled in the art in the position to access compounds of formula I of present invention, starting from 3-isochromanone.

3-lsochromanone of formula V does not have any further functional groups and may therefore be easily cleaved. Surprisingly, it has been found that the compounds of for- mula Il according to the present invention can be cleaved to compounds of formula I, in spite of their sensitive substituent(s). In a preferred embodiment, the invention comprises the use of 3-isochromanone of formula V for the production of 2-halogenomethylphenyl acetic acid derivatives of formula I., which includes cleavage of an alkyloxime of formula Il

wherein

R 2 is methyl or ethyl; in the presence of an alcohol of formula III

R 1 -OH (III), wherein R 1 is R 1 is methyl, ethyl, n-propyl or i-propyl; and a halogenating agent selected from the group consisting of thionyl halide, oxalyl halides and mixtures of thionyl bromide and hydrobromic acid, mixtures of thionyl chloride and hydrochloric acid or mixtures of oxalyl chloride and hydrochloric acid and mixtures of oxalyl bromide and hydrobromic acid.

In a further embodiment, the 2-halogenomethylphenyl acetic acid derivatives of formula I, wherein R 2 is methyl or ethyl, can be produced based on 2-halogenomethylphenyl acetic acid derivatives of formula I, wherein R 2 is hydrogen, by alkylating compounds of formula I, wherein R 2 is hydrogen, in an inert organic solvent. Suitable alkylating agents are widely known to the skilled artisan. Examples of suitable alkylating agents are dimethylsulfate, methyliodide, methylbromide, methylchloride, diazomethane and diethylsulfate, ethyliodide, ethylbromide, ethylchloride. Preferred alkylating agents are dimethylsulfate and methyliodide, more preferably dimethylsulfate. Suitable bases are widely known to the skilled artisan. Examples of suitable bases in- elude, but are not limited to potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide. Preferred bases are potassium carbonate and sodium carbonate, more preferably potassium carbonate. Useful solvents include aromatic (halo- genated) hydrocarbons, e.g. benzene, toluene, xylene, chlorobenzene, dichloroben- zene, bromobenzene and benzotrifluoride; aliphatic (halogenated) hydrocarbons, e.g. pentane, heptane, dichloromethane, chloroform, 1 ,2-dichloroethane and carbon tetrachloride; cycloaliphatic hydrocarbons, e.g. cyclohexane and cyclopentane; ethers, e.g. dimethoxyethane, diethyl ether and di-isopropyl ether; esters, e.g. ethyl acetate and butyl acetate and polar aprotic solvents such as dimethylformamide, N- methylpyrrolidone, dimethylsulfoxide. Also mixtures of these solvents may be used. Preferred solvents include aromatic (halogenated) hydrocarbons, e.g. benzene, toluene, xylene, chlorobenzene and dichlorobenzene; aliphatic (halogenated) hydrocarbons such as e.g. dichloromethane, chloroform, 1 ,2-dichloroethane and carbon tetra- chloride and polar aprotic solvents such as dimethylformamide, N-methylpyrrolidone. Also mixtures of these solvents may be used.

The reaction pressure is customarily from 0 to 6 bar. Preference is given to carrying out the reaction under atmospheric pressure. If the reaction is carried out under atmospheric pressure, the reaction temperature is customarily from 0 to 100 0 C, preferably from 10 to 40 0 C, more preferably from 15 to 30°C.

The present invention also comprises a process for the production of 2- halogenomethylphenyl acetic acid derivatives of formula I, wherein R 2 is methyl or ethyl, said method comprising.

a) reacting a compound of formula V with a nitrosating agent under the conditions described above, alkylating of the resulting oxime of formula IV under the condi- tions described above and cleavage of the obtained alkyloxime of formula Il under the conditions described above, or

b) reacting a compound of formula V with a nitrosating agent as described above, cleavage of the obtained oxime of formula IV as described above and subse- quent alkylation of the resulting 2-halogenomethylphenyl acetic acid derivatives of formula I, wherein R 2 is hydrogen, as described above.

The present invention furthermore comprises a process for the production of a stro- bilurine fungicide selected from the group consisting of dimoxystrobin, trifloxystrobin, kresoxime-methyl, orysastrobin, said process comprising.

(1 ) cleavage of an alkyloxime of formula Il in the presence of an alcohol of formula III and a halogenating agent selected from the group consisting of thionyl halide, oxalyl halides and mixtures of thionyl bromide and hydrobromic acid, mix- tures of thionyl chloride and hydrochloric acid or mixtures of oxalyl chloride and hydrochloric acid and mixtures of oxalyl bromide and hydrobromic acid; and

(2) reacting the resulting 2-halogenomethylphenyl acetic acid derivatives of formula I to the strobilurine or the respective strobilurine precursor.

The methods for producing the strobilurins mentioned above based on 2-halogeno- methylphenl acetic acid derivatives are generally known to the skilled artisan.

For example, orysastrobin can be prepared using compounds of formula I in accor- dance with the methods described in WO 97/15552. Variations on this synthesis may easily be employed by a skilled person using the disclosure of this invention. The strobilurines kresoxim-methyl and dimoxystrobine can be prepared using compounds of formula I by substitution reaction with the respective phenol derivative according to the methods described in WO 2008/125592 A1. Variations on this synthesis may easily be employed by a skilled person using the disclosure of this invention.

The strobilurine trifloxystrobin can be prepared using compounds of formula I by substitution with the respective 3-trifluoromethylacetophenone oxime according to the methods described in DE19508573 A and CN 1793115 A. Variations on this synthesis may easily be employed by a skilled person using the disclosure of this invention.

The invention is further illustrated but not limited by the following examples:

Example 1 : lsochroman-3,4-dione 4-oxime [identical to 4-(Hydroxyimino)isochroman-3- one] by nitrosation of isochromanone

To a suspension of isochromanone (99% pure, 149.7g, 1.00 mol) in methanol (280 ml.) was added dropwise over a period of 90 min at 14-16 0 C sodium methanolate (30 % in methanol, 270.0 g, 1.50 mol) and the resulting mixture was stirred for 90 min at 15 0 C. To this mixture was added dropwise over a period of 6.5 h at 9-13 0 C iso-butyl nitrite (94% pure, 137.1 g, 1.25 mol) and the mixture was stirred at 8 0 C overnight. The conversion was monitored by HPLC. After completion of the reaction, 4 M hydrochloric acid was added to adjust a pH<1 before the resulting suspension was stirred for overnight at 4°C. The crude product was collected by filtration, washed with cold dist. water (2x 500 ml.) and dried in vacuo at max. 45°C. lsochroman-3,4-dione-4-oxime was ob- tained as a colorless solid (145.9 g, 90.4 HPLC-area %, 74% yield).

1 H-NMR (DMSO-d6): δ = 13.3 (s, 1 H), 8.34 (d, J = 7.4 Hz, 1 H), 7.54-7.41 (m, 3H), 5.46 (s, 2H) ppm; 13 C-NMR (DMSO-d6): δ = 162.3, 140.2, 133.2, 130.2, 129.0, 127.9, 125.4, 125.0, 68.3 ppm; mp = 179-182 0 C.

Example 2: lsochroman-3,4-dione 4-(O-methyl-oxime) [identical to 4-(Methoxyimino)- isochroman-3-one] by methylation of isochroman-3,4-dione 4-oxime

A suspension of isochroman-3,4-dione 4-oxime (90.4 HPLC-area %, 145.8 g, 0.74 mol) and potassium carbonate (153.4 g, 1.11 mol) in toluene (1000 mL) was stirred at ambient temperature for 1 h before dimethylsulfate (141.4 g, 1.1 1 mol) was added dropwise at 26 0 C over a period of 2.5 h. The resulting mixture was stirred for 24 h at ambient temperature. After completion of the reaction, dist. water (1000 mL) was added to the mixture under stirring. The organic layer was separated, washed with dist. water (500 mL) and dried in vacuo at 30-50 mbar and max. 50 0 C. lsochroman-3,4-dione 4-(O- methyl-oxime) was obtained as a light orange solid (160.1 g, 88.7 HPLC-area %, quant, yield, diastereomeric ratio = 58:42). 1 H-NMR (CDCI 3 JMS as internal standard) (main isomer): δ = 8.27-8.24 (m, 1 H), 7.48- 7.40 (m, 2H), 7.31-7.27 (m, 1 H), 5.35 (s, 2H), 4.22 (s, 3H) ppm; 13 C-NMR (CDCI 3 JMS as internal standard) (main isomer): δ = 162.2, 140.5, 133.0, 131.0, 130.0, 128.4, 125.4, 124.8, 69.1 , 65.5 ppm.

Example 3: (2-Chloromethyl-phenyl)-[(E)-methoxyimino]-acetic acid methyl ester (CLMO) by addition of thionyl chloride to isochroman-3,4-dione 4-(O-methyl-oxime) in methanol

To a solution of isochroman-3,4-dione 4-(O-methyl-oxime) (88.7 HPLC-area %, 160 g, 0.74 mol, diastereomeric ratior = 58 : 42) in methanol (890 g, 27.74 mol) was added dropwise at 15-20 0 C over a period of 5 h thionyl chloride (889.5 g, 7.40 mol) and the mixture was stirred overnight at ambient temperature (20-25 0 C). The conversion was monitored by HPLC. After completion of the reaction, the solvent was evaporated in vacuo at 30-50 mbar and max. 55 0 C. The resulting residue (216 g) was dissolved in toluene (500 mL), dist. water was added (300 mL) and the mixture was stirred at ambient temperature. The phases were separated and the organic phase was evaporated in vacuo at 30-50 mbar and max. 55 0 C to yield the crude product as a colorless oil (179 g, 56.7 HPLC-weight % CLMO, 54% yield). Recrystallization of the crude product from methanol (89 g) led to colorless crystals of (2-Chloromethyl-phenyl)-[(E)- methoxyimino]-acetic acid methyl ester CLMO (64.7g, 94.7 HPLC-weight %, 34% yield). 1H-NMR (CDCI 3 , TMS as internal standard): δ = 7.50-7.47 (m, 1 H), 7.43-7.35 (m, 2H), 7.18-7.14 (m, 1 H), 4.42 (s, 2H), 4.03 (s, 3H), 3.85 (s, 3H) ppm; 13 C-NMR (CDCI 3 , TMS as internal standard): δ = 163.2, 149.0, 135.5, 130.2, 129.8, 129.6, 128.6, 128.4, 63.8, 53.0, 44.0 ppm.

Example 4: (2-Chloromethyl-phenyl)-[(E)-methoxyimino]-acetic acid methyl ester

(CLMO) by addition of methanolic HCI and thionyl chloride to isochroman-3,4-dione 4- (O-methyl-oxime)

To a freshly prepared solution of gaseous HCI (21 g) in methanol (20 g) [HCI gas was inserted at -10 0 C] was added dropwise at -10 0 C a solution of isochroman-3,4-dione 4-(O-methyl-oxime) (89.5 HPLC-area %, 14.8 g, 0.069 mol) in methanol (82.9 g). After completion of addition, thionyl chloride (4.6 g, 38 mmol) was added dropwise below 0 0 C and the resulting mixture was stirred overnight. HPLC indicated a conversion of the isochroman-3,4-dione 4-(O-methyl-oxime) >97% HPLC-area %. The solution contained (2-chloromethyl-phenyl)-[(E)-methoxyimino]-acetic acid methyl ester of 72% HPLC- area % purity. Work-up can be performed according to example 3. Example 5: (2-Chloromethyl-phenyl)-[(E)-methoxyimino]-acetic acid ethyl ester by addition of thionyl chloride to isochroman-3,4-dione 4-(O-methyl-oxime) in ethanol:

The synthesis was performed according to the procedure described in example 3 using ethanol as a solvent.

1 H-NMR (CDCI 3 , TMS as internal standard): δ = 7.51-7.47 (m, 1 H), 7.43-7.34 (m, 2H), 7.18-7.14 (m, 1 H), 4.44 (s, 2H), 4.33 (q, J = 7.1 Hz, 2H), 4.04 (s, 3H), 1.32 (t, J = 7.1 Hz, 3H) ppm. 13 C-NMR (CDCI 3 , TMS as internal standard): δ = 162.8, 149.3, 135.5, 130.4, 129.7, 129.6, 128.6, 128.3, 63.8, 62.2, 44.0, 14.1 ppm.

Example 6: (2-Chloromethyl-phenyl)-[(E)-methoxyimino]-acetic acid ethyl ester by addition of addition of ethanolic HCI and thionyl chloride to isochroman-3,4-dione 4-(O- methyl-oxime):

The synthesis was performed according to the procedure described in example 4 using ethanol as a solvent.

Example 7: (2-Bromomethyl-phenyl)-[(E)-methoxyimino]-acetic acid methyl ester (BRMO) by addition of thionyl bromide to isochroman-3,4-dione 4-(O-methyl-oxime)

To a solution of isochroman-3,4-dione 4-(O-methyl-oxime) (5.6 g, 0.028 mol) in metha- nol (27 g) was added dropwise at 10-20 0 C thionyl bromide (45.4 g, 0.22 mol) over a period of 1 h and the resulting mixture was stirred at ambient temperature overnight. The reaction was monitored by HPLC. Concentration of the mixture in vacuo led to a crude residue (14.2 g). A small amount of the residue (3.2 g) was purified by silica column chromatography to yield (2-bromomethyl-phenyl)-[(E)-methoxyimino]-acetic acid methyl ester as a colorless solid (0.8 g).

1 H-NMR (CD 2 CI 2 , TMS as internal standard): δ = 7.50-7.46 (m, 1 H), 7.43-7.35 (m, 2H), 7.16-7.12 (m, 1 H), 4.34 (s, 2H), 4.02 (s, 3H), 3.83 (s, 3H) ppm; 13 C-NMR (CD 2 CI 21 TMS as internal standard): δ = 163.4, 149.2, 136.3, 131.1 , 130.5, 130.1 , 129.2, 128.8, 64.1 , 53.2, 31.3 ppm.

Example 8: (2-Chloromethyl-phenyl)-hydroxyimino-acetic acid methyl ester by addition of thionyl chloride to isochroman-3,4-dione 4-(O-methyl-oxime) in methanol and di- chloromethane

To a solution of isochroman-3,4-dione 4-oxime (98% pure, 3.5 g, 0.02 mol) in methanol (35 g) and dichlormethane (32 g) was added dropwise at 20-30 0 C thionyl chloride (24.0 g, 0.2 mol). The resulting mixture was stirred at ambient temperature for 3 d. The reaction was monitored by HPLC. After completion of the reaction, the mixture was concentrated in vacuo and a crude residue was obtained (5.5 g). A part of this residue (5.1 g) was dissolved in MTBE and was washed with water. The mixture was concentrated and the resulting residue was purified by silica column chromatography by yield (2-chloromethyl-phenyl)-hydroxyimino-acetic acid methyl ester as a colorless solid (3.4 g)-

Example 9: (2-Chloromethyl-phenyl)-[(E)-methoxyimino]-acetic acid methyl ester (CLMO) by methylation of (2-chloromethyl-phenyl)-hydroxyimino-acetic acid methyl ester

The synthesis was performed according to the procedure described in example 2.

Example 10: Synthesis of Orysastrobin from (2-Chloromethyl-phenyl)-[(E)- methoxyimino]-acetic acid methyl ester (CLMO)

A solution of (2E, 3Z, 4E)-pentane-2,3,4-trione O 2 ,O 3 -dimethyl trioxime and its (2E, 3Z, 4Z)- isomer (36,8% in DMF) (101.7g, 0.200 mol) was treated at 20 0 C with a solution of sodium methylate (30% in methanol) (39.5 g, 0.219 mol). After 15 min at 20 C the methanol was distilled off in vacuo at 40 0 C. Afterwards, a solution of (2-Chloromethyl-phenyl)-[(E)-methoxyimino]-acetic acid methyl ester (CLMO) (45% in DMF) (1 13.4g, 0.200mol) was added to the residue at 40 to 50 0 C within 15 min and the reaction mixture was stirred at 50 0 C for 3 hours. For the amidation step a solution of methylamine (18.6 g, 0.600 mol) in methanol (65.7 g) was added to the mixture and the resulting reaction mixture was stirred for 3 hours at 50 0 C. Methylamine and methanol were then distilled off in vacuo at 50 0 C. After an extraction with toluene and a water wash, toluene was distilled off giving rise to 74.9 g of crude residue. The crude residue was dissolved at 50 0 C in a mixture of methanol (248 g) and water (186 g) and was then cooled to -5 °C for crystallization. The resulting crystals were filtered off and were washed afterwards with a metha- nol/water mixture followed by a rinse with water. The solid was dried in vacuo at 70°C yielding 48.5 g of a solid that contained 95% of the EEE-isomer of Orysastrobin and 4.5% of its EEZ-isomer.

1 H-NMR (CD 2 CI 21 TMS as internal standard) (main isomer): δ = 7.41-6.95 (m, 4H), 5.03 (s, 2H), 3.89 (s, 3H), 3.88 (s, 3H), 3.86 (s, 3H), 2.76 (d, J = 5.0 Hz, 3H), 1.97 (s, 3H), 1.86 (s, 3H) ppm; 13 C-NMR (CD 2 CI 2 , TMS as internal standard) (main isomer): δ =

163.0, 153.7, 152.2, 151.5, 150.7, 136.0, 130.8, 129.2, 129.2, 129.2, 128.0, 76.0, 63.3, 63.2, 61.9, 26.2, 14.7, 10.3 ppm; mp = 95-96 °C.