DE3828059A1 - Process for the preparation of side chain-halogenated alkylbenzene derivatives - Google Patents

Abstract

The invention relates to a novel process for the preparation of side chain-halogenated alkylbenzene derivatives of the formula (I) <IMAGE> in which R stands for hydrogen, cyano, carboxyl, alkoxycarbonyl or optionally substituted alkyl, X stands for chlorine or bromine, Y stands for hydrogen or halogen and Z stands for hydrogen, halogen, cyano or optionally substituted phenoxy, by reaction of alkylbenzene derivatives of the general formula (II) <IMAGE> in which R, Y and Z have the meanings indicated above, with chlorine or bromine, optionally in the presence of a diluent, which is characterised in that the reaction is carried out in the presence of a catalyst at temperatures between 0 and 150@C.

Description

The invention relates to a new method of manufacture of side chain halogenated alkylbenzene derivatives.

It is known that the reaction of alkylbenzene derivatives with chlorine or bromine depending on the reaction conditions leads to different products. At high temperatures, possibly under exposure, are mainly side chain halogenated products educated; at low temperatures, possibly in However, the presence of catalysts is predominantly obtained nuclear halogenated products.

A new process for the production of side chain halogenated alkylbenzene derivatives of the general Formula (I)  

in which

R represents hydrogen, cyano, carboxy, alkoxycarbonyl or optionally substituted alkyl,
X represents chlorine or bromine,
Y represents hydrogen or halogen and
Z represents hydrogen, halogen, cyano or optionally substituted phenoxy,

by reaction of alkylbenzene derivatives of the general Formula (II)

in which

R, Y and Z have the meanings given above,
with chlorine or bromine, optionally in the presence of a diluent,

which is characterized in that the implementation in the presence of a catalyst at temperatures between 0 ° C and 150 ° C.

It is to be regarded as extremely surprising that side-chain halogenated by the inventive process alkylbenzene derivatives are obtained highly selective and in very good yields, since experience shows that was to be expected rather nuclear halogenation with the use of catalysts (J. March, Advanced Organic Chemistry, ^3rd Edition, 1985, 476 -479; John Wiley and Sons, New York).

The advantages of the method according to the invention lie in addition to the simple implementation mainly in the excellent selectivity of halogenation and in the high yields that are achieved. The The method according to the invention thus represents a valuable one Technology enrichment.

If, for example, 3- [3- (2- Chloro-6-fluoro-4-trifluoromethyl-phenoxy) -phenyl] -propionic acid- methyl ester and chlorine and platinum as a catalyst, the reaction can be carried out using the following formula are outlined:

The hydrocarbon chains listed in the definitions such as alkyl, alkoxy, alkylthio, alkylsulfinyl or Alkylsulfonyl are each straight-chain or branched.

With the help of the method according to the invention preferably the side chain halogenated alkylbenzene derivatives of formula (I) in which

R represents hydrogen, cyano, carboxy, C₁-C₆alkoxycarbonyl or C₁-C₆alkyl which is optionally substituted by fluorine, chlorine, bromine, cyano and / or C₁-C₄alkoxycarbonyl,
Y represents hydrogen, fluorine, chlorine or bromine,
Z for hydrogen, fluorine, chlorine, bromine, cyano or for optionally up to five times, identical or different, by fluorine, chlorine, bromine, cyano, halogen- C₁-C₄-alkyl, halogen-C₁-C₄-alkoxy, halogen-C₁- C₄-alkylthio, halogen-C₁-C₄-alkylsulfinyl and halogen-C₁-C₄-alkylsulfonyl substituted phenoxy.

Compounds of the Formula (I) in which

R represents hydrogen, cyano, carboxy, C₁-C₄-alkoxy-carbonyl or C₁-C₄-alkyl which is optionally substituted by fluorine, chlorine, bromine, cyano, carboxy and / or C₁-C₄-alkoxy-carbonyl,
Y represents hydrogen, fluorine, chlorine or bromine and
Z for hydrogen, fluorine, chlorine, bromine, cyano or for optionally single to fourfold, identical or different by fluorine, chlorine, bromine, cyano, difluoromethyl, chlorodifluoromethyl, fluorodichloromethyl, trifluoromethyl, difluoromethoxy, chlorodifluoromethoxy, fluorodichloromethoxy, trifluoromethoxy, difluorodomifluoromethyl Fluorodichloromethylthio, trifluoromethylthio, difluoromethylsulfinyl, chlorodifluoromethylsulfinyl, fluorodichloromethylsulfinyl, trifluoromethylsulfinyl, difluoromethylsulfonyl, chlorodifluoromethylsulfonyl, fluorodichloromethylsulfonyl and trifluoromethylsulfonyl.

Those compounds are very particularly preferred of the formula (I), in which

R represents hydrogen, cyano, methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, cyanomethyl, methoxycarbonylmethyl, ethoxycarbonylmethyl, propoxycarbonylmethyl or isopropoxycarbonylmethyl,
Y represents hydrogen, chlorine or bromine and
Z represents phenoxy which is mono- to tetrasubstituted, identically or differently, by fluorine, chlorine, cyano and trifluoromethyl or trifluoromethylsulfonyl.

To carry out the method according to the invention are alkylbenzene derivatives required as starting materials defined by formula (II). In this formula (II)  R, Y and Z preferably represent those radicals which already in the description of the invention Substances of formula (I) as preferred for these substituents were called.

Examples of the starting materials of the formula (II) are listed in Table 1 below.

Table 1

Examples of the starting materials of the formula (II)

The starting materials of the formula (II) are known and / or can be produced by methods known per se (see DE-AS 23 04 006, DE-OS 34 19 952, EP-A 23 890, EP-A 56 119).

The inventive method is preferably under Use of diluents. As Diluents come in handy in addition to water all relatively inert organic solvents in question. These preferably include halogenated hydrocarbons, such as methylene chloride, ethylene chloride, chloroform, Carbon tetrachloride, chlorobenzene and o-dichlorobenzene and Carboxylic acids, preferably aliphatic carboxylic acids, such as acetic acid and propionic acid, carbon tetrachloride as a solvent for the process according to the invention particularly preferred.

The process according to the invention is carried out in the presence of a Catalyst carried out. Coming as catalysts here preferably metals into consideration generally as catalysts in catalytic hydrogenations are used, but also their salts.

As examples of those to be used according to the invention Catalysts may be mentioned: nickel, especially Raney Nickel, nickel (II) acetate, nickel (II) bromide, nickel (II) - chloride, nickel (II) nitrate, nickel (II) sulfate, Cobalt, cobalt (II) acetate, cobalt (II) chloride, cobalt (II) - nitrate, cobalt (II) sulfate, copper, copper (II) - acetate, copper (II) bromide, copper (II) chloride, copper (II) - nitrate, copper (II) oxide, copper (II) sulfate, copper chromite, Palladium, Palladium (II) acetate, Palladium (II) -  chloride, palladium (II) nitrate, palladium (II) oxide, platinum, Platinum (II) chloride, platinum (IV) chloride and platinum (IV) - oxide, the metal salts optionally as Hydrates are used.

Nickel, Raney nickel, nickel (II) are preferably used. chloride and nickel (II) sulfate and their hexahydrates and palladium (II) chloride.

The reaction temperatures can in the inventive Procedures can be varied over a wide range. Generally one works at temperatures between 0 ° C and 150 ° C, preferably at temperatures between 20 ° C and 100 ° C.

The process according to the invention is generally described in Normal pressure carried out. However, it is also possible to work under increased or reduced pressure.

To carry out the method according to the invention to 1 mol of alkylbenzene derivative of the formula (II) in generally between 0.9 and 1.5 moles, preferably between 1.0 and 1.2 moles, chlorine or bromine, and between 0.001 and 0.1 mol, preferably between 0.005 and 0.05 Mole, catalyst.

The reaction components are generally at Combined at room temperature or with gentle cooling and, if necessary at elevated temperature, up to stirred at the end of the implementation. The workup can be carried out according to customary methods. In general is, if necessary after concentration, with water  and an organic water that is practically immiscible with water Solvents such as B. methylene chloride, chloroform or tetrachloromethane, shaken, the organic Phase separated, optionally dried and filtered. The solvent is reduced from the filtrate Pressure carefully distilled off Product of formula (I) remains in the residue. The Further cleaning can be carried out using conventional methods, for example performed by column chromatography will.

Those to be produced by the method according to the invention Compounds of formula (I) can be used as herbicides or can be used as intermediates for herbicides (cf. EP-A 23 890, EP-A 56 119, DE-P 38 12 768 dated April 16, 1984 and DE-P 37 36 089 of October 24, 1987).

Manufacturing examples example 1

A mixture of 5.9 g (0.015 mol) of 3- [3- (2,6-dichloro-4- trifluoromethyl-phenoxy) -phenyl] -propionic acid methyl ester, 0.1 g Raney nickel, 2.4 g (0.015 mol) bromine and 100 ml of carbon tetrachloride is refluxed for 60 minutes heated to boiling. Then the reaction solution with Washed water, dried with sodium sulfate and filtered. The solvent is removed from the filtrate in a water jet vacuum carefully distilled off.

7.0 g (99% of theory) of 3-bromo- [3- (2,6- dichloro-4-trifluoromethylphenoxy) phenyl] propionic acid methyl ester as an oily residue.

Example 2

A mixture of 16.4 g (0.046 mol) of 3- (2,3,6-trichloro- 4-trifluoromethylphenoxy) toluene, 0.1 g nickel (II) - chloride hexahydrate, 8 g (0.05 mol) bromine and 200 ml Tetrachloromethane is refluxed for 15 hours Boiled and then as described in Example 1 worked up.

19.5 g (98% of theory) of 3- (2,3,6-trichloro- 4-trifluoromethyl-phenoxy) benzyl bromide as an oily residue.

When using palladium (II) chloride instead of Nickel (II) chloride hexahydrate will be the same product obtained in an equally high yield (98% of theory).

Example 3

When using 3- [2-chloro-5- (2,6-dichloro-4-trifluoromethyl- phenoxy) phenyl] propionic acid methyl ester and Bromine in equimolar amounts is analogous to Example 1, with a yield of 99.2% of theory, 3-bromo-3- [2- chloro-5- (2,6-dichloro-4-trifluoromethylphenoxy) phenyl] - Get methyl propionate as a yellowish oil.

Claims (8)

1. Process for the preparation of side-chain halogenated alkylbenzene derivatives of the formula (I), in which
R represents hydrogen, cyano, carboxy, alkoxycarbonyl or optionally substituted alkyl,
X represents chlorine or bromine,
Y represents hydrogen or halogen and
Z represents hydrogen, halogen, cyano or optionally substituted phenoxy,
by reaction of alkylbenzene derivatives of the general formula (II) in which
R, Y and Z have the meanings given above,
with chlorine or bromine, optionally in the presence of a diluent,
which is characterized in that one carries out the reaction in the presence of a catalyst at temperatures between 0 and 150 ° C. 2. The method according to claim 1, characterized in that side chain halogenated alkylbenzene derivatives of the formula (I) in which
R represents hydrogen, cyano, carboxy, C₁-C₆alkoxycarbonyl or C₁-C₆alkyl which is optionally substituted by fluorine, chlorine, bromine, cyano and / or C₁-C₄alkoxycarbonyl,
Y represents hydrogen, fluorine, chlorine or bromine,
Z for hydrogen, fluorine, chlorine, bromine, cyano or for optionally up to five times, the same or different by fluorine, chlorine, bromine, cyano, halogen-C₁-C₄-alkyl, halogen-C₁- C₄-alkoxy, halogen-C₁- C₄-alkylthio, halogen-C₁-C₄-alkylsulfinyl and halogen-C₁-C₄-alkylsulfonyl substituted phenoxy,
getting produced. 3. The method according to claim 1, characterized in that nickel, nickel (II) acetate, nickel (II) bromide,  Nickel (II) chloride, nickel (II) nitrate, nickel (II) - sulfate, cobalt, cobalt (II) acetate, cobalt (II) - chloride, cobalt (II) nitrate, cobalt (II) sulfate, Copper, copper (II) acetate, copper (II) bromide, Copper (II) chloride, copper (II) nitrate, copper (II) - oxide, copper (II) sulfate, copper chromite, palladium, Palladium (II) acetate, palladium (II) chloride, Palladium (II) nitrate, palladium (II) oxide, platinum, Platinum (II) chloride, platinum (IV) chloride and Platinum (IV) oxide - the metal salts if necessary as hydrates - can be used as catalysts. 4. The method according to claim 3, characterized in that nickel, Raney nickel, nickel (II) chloride and Nickel (II) sulfate and their hexahydrates and Palladium (II) chloride used as catalysts will. 5. The method according to claim 1, characterized in that the reaction in the presence of a diluent is carried out. 6. The method according to claim 5, characterized in that that water, halogenated hydrocarbons or Carboxylic acids used as diluents will. 7. The method according to claim 6, characterized in that that methylene chloride, ethylene chloride, chloroform, Carbon tetrachloride, chlorobenzene, o-dichlorobenzene, Acetic acid or propionic acid as a diluent is used.   8. The method according to claim 1, characterized in that that for 1 mol of alkylbenzene derivative of the formula (II) 0.9 to 1.5 moles of chlorine or bromine and 0.001 to 0.1 mol of catalyst is used.