DE3738680A1 - Novel alpha-phenoxycarboxylic acids and their derivatives - Google Patents

Abstract

The invention relates to novel alpha -[phenoxy]carboxylic acids, -carboxylates, -carboxamides and -alkyloxazolidines, to a process for their preparation, and to the use of these compounds in crop protection.

Description

The invention relates to new α - (2- or 6-halo-3-methyl-4-nitrophenyloxy) carboxylic acids, esters, amides and the corresponding 2- [ α- phenoxyalkyl] oxazolines, their preparation and use as herbicides.

The compounds of the invention are characterized by the general formula I described,

which also the stereoisomers derived therefrom Compounds in any mixture or in pure Form, and optionally their salts with one, two or or trivalent cations, wherein

X or Y for halogen
R¹ is hydrogen or C₁-C₄ alkyl
Z for the rest

is in which n can take the values 0 to 2 R¹ is as previously defined and may be the same or different
or for the rest

stands in the

R² is hydrogen, C₁-C₁₀ alkyl, alkoxyalkyl having up to 4 carbon atoms, an alkenyl group having up to 6 carbon atoms or an alkynyl group having up to 6 carbon atoms
or for the rest

stands in the

R³, R⁴ which may be the same or different are hydrogen, C₁-C₆-alkyl or together represent a - (CH₂) _m group with m = 4 to 6.

The alkyl groups in the sense of the above definition can straight or branched, d. H. for methyl, ethyl, n-propyl, iso-propyl, n-butyl, butyl-2, iso-butyl, tert-butyl, the various isomeric pentanyls, in particular Neopentyl, the various isomeric hexanyls, octanyls, Nonanyle and Decanyle stand.

The alkenyl groups can be straight-chain or branched and include both the constitutional isomers and the cis-trans isomeric structures of the hexenyls, pentenyls, Methyl pentenyls, butenyls, alkyl-substituted butenyls, Propenyls, alkyl substituted propenyls and the vinyl group.

The alkynyl groups include those which are optionally alkyl-substituted isomeric hexinyls, pentinyls, butinyls as well as the propargyl group.

Halogens are fluorine, chlorine, bromine and iodine. One of the substituents X and Y is halogen, the other hydrogen. Carboxylic acids of formula I (R₂ is hydrogen) z. B. as salts with alkali or alkaline earth cations (Na⁺, K⁺, Mg²⁺,  Ca²⁺ or as salts with organic ions (e.g. with trimethylammonium, triethylammonium). Alkoxy-alkyl groups can the radicals 3-methoxypropyl, 2-methoxypropyl, 1-methoxypropyl, 2-ethoxyethyl, 1-ethoxyethyl, Propyloxymethyl, isopropyloxymethyl and 1-methoxy-1-methyl-ethyl mean.

To be emphasized are compounds of the general formula I at them

X or Y for fluorine, chlorine or bromine
R¹ is hydrogen, methyl or ethyl
Z for the rest

in which n can assume the values 0 to 2, R 1 is as previously defined and can be the same or different,
or for the rest

stands in the

R² is hydrogen, C₁-C₈-alkyl or ethoxyethyl,
or for the rest

stands in the

R³, R⁴, which may be the same or different, stand for hydrogen, C₁-C₄-alkyl or together for a - (CH₂) group with m = 4 to 6.

The invention further relates to methods of manufacture of compounds of the general formula I according to:

Procedure A

A phenol (M = H) or phenolation (M = cation) which Formula II

is with a compound of formula

implemented in which R¹ and Z have the meaning given above and W for a nucleophilically exchangeable group, such as Cl, Br, I, p-toluenesulfonyl, N₃ etc. is.

The implementation takes place according to known methods for nucleophilic substitution. Thereby solvents higher polarity preferred for those without, however, the selection The following representatives should be named: Alcohol such as B. methanol, ethanol, n-propanol, isopropanol, n-butanol, butanol-2, isobutanol, tert-butanol; Ketones such as B. acetone, 2-butanone, cyclohexanone, etc; Esters such as B. ethyl acetate, butyl acetate Etc; Dimethylformamide; N-methylpyrrolidone; Dimethyl sulfoxide; Pyrides; Tetrahydrofuran; Water; Glacial acetic acid a.

The solvents can be as pure solvents or but can be used in mixtures.  

A base such as triethylamine, Pyridine or quinoline can be added to the case acid HY released during the reaction.

The reaction is preferred at the boiling point of the Solvent carried out under normal pressure. she can but also at temperatures below the boiling point of the solvent. When implementing under Pressure in closed vessels, such as. B. autoclaves, are reaction temperatures above the boiling point of the solvent possible.

For the preparation of compounds of formula I with Z = COOH d. H. of free carboxylic acids, the reaction can be beneficial by reacting II and III in aqueous alkaline Solution carried out at temperatures between 0 ° C and 100 ° C. be, the product I with Z = COOH by acidification of the reaction mixture easily in pure form isolate.

Another advantageous method for the synthesis of Compounds I according to the invention is the implementation of Phenol II with compound III under phase transfer conditions.

By using chiral starting compounds of the general formula III, it is possible to synthesize an optically active product I, whereby it should be noted that the stereochemistry in the product I is inverse to the configuration of the starting compound III because of Walden's reversal at the a -C atom is.

Procedure B

Compounds of general formula I, which with Z = COR² (R² ≠ H) and CONR³R⁴ as carboxylic acid esters, or Carboxamides can also be viewed through Esterification and amidation reactions from compounds of formula I with Z = COOH by generally known methods getting produced.

Suitable processes for direct esterification or amidation of carboxylic acids are the implementation of compounds of the Formula I with Z = COOH with alcohols or amines of the formula IV or V.

The carboxylic acid I with Carbodiimidazole or cyclohexylcarbodiimide or chloroformate or another suitable connection in transferred a reactive form and with the corresponding one Alcohol IV or amine V converted to product I.

Procedure C

Another process for the synthesis of carboxylic acid esters or amides of the general formula I (Z = COOR² or CONR³R⁴) consists in the implementation of carboxylic acid halides of the formula

with alcohols IV or amines V. The carboxylic acid halides of the formula VI are general known methods easily from the corresponding Carboxylic acids of the formula (Z = COOH) z. B. by implementation accessible with thionyl chloride.

Procedure D

Compounds of the formula I with Z = oxazolinyl-2 can be cyclized by appropriately substituted β- ethanolamines

with carboxylic acids or carboxylic acid derivatives z. B. the Formulas I or VI according to methods known per se (e.g. Seeliger et al; Appl. Chem; 78 913 (1966) or also by Implementation of ethanolamines VII with aldehydes of the formula

according to methods also known from the literature (e.g. Eiter et al; Liebigs Ann. Chem; 76 555 (1972) will.  

Procedure E

Compounds of formula I can also by nitriding Compounds in position 4 of the phenoxy radical unsubstituted

or by halogenation reactions of the compounds

be produced by methods known per se.

The targeted incorporation of halogen substituents into the Position 2 or 6 of the phenoxy radical can also be through other methods familiar to the person skilled in the art, such as e.g. B. the Sandmeyer or the Balz-Schiemann reaction.

The necessary 2- or 6-aminophenols can in the Process stages A to E are used, with the introduction of halogen at any suitable stage in the process is possible.

Optically active compounds of formula I can by Use of optically active starting materials on any Stages of processes A to E are synthesized. If desired, methods A to E can be obtained Carboxylic acids of formula I (Z is COOH) in the usual Way in salts, carboxylic acid salts obtained in the free carboxylic acids are transferred.  

The compounds of formula I are herbicidally active. You can face numerous before and after emergence Weeds and grasses are used, e.g. B. against Field mustard, burdock herb, chamomile, field fox tail, Chicken millet, wild oats, amaranth, almond grass, nut grass.

The good selectivity of the new compounds enables it, weed control or weed control in numerous Performing crops, for example in wheat, Corn, rice, barley, potatoes, tomatoes, sunflowers, Peas, beans, beets, cotton.

For the application, the compounds of formula I in a manner known per se with usual auxiliary and or carriers processed into common formulations, e.g. B. to emulsion concentrates or suspension powders, where the active ingredient content between 10 and 95 percent by weight and that for the application with water to the desired active ingredient concentration be diluted. However, they can also be used undiluted Preparations are made, such as granules and Dusts. The active substance content here is between 0.01 and 10 percent by weight, preferably between 0.1 and 3 Percent by weight.

In weed control after casserole, it has proven to be proven to be advantageous with high-boiling emulsion concentrates To use solvents. This allows the Effectiveness of the agent can be increased significantly.  

Formulation examples (Specification of the composition in percent by weight) 1. Dusts

0.3% of a compound of formula I.
1.0% methyl cellulose
98.7% talc

2. Solution concentrate

20% of a compound of formula I.
30% Shellsol A (liquid mixture of aromatic hydrocarbons, boiling range 140-180 ° C)
40% acetone
10% Emulsogen I 40 (anionic emulsifier)

3. Suspension powder

95% of a compound of formula I.
4% calcium lignin sulfonate
1% sodium tetrapropylene benzene sulfonate

4. Emulsion concentrate

10% of a compound of formula I.
80% dimethylformamide
6.5% Tensiofix AS (emulsifier)
3.5% Tensiofix DS (emulsifier)

5. Emulsion concentrate

20% of a compound of formula I.
4% calcium dodecylbenzenesulfonic acid (emulsifier)
6% Marlowet EF emulsifier (carboxylic acid polyglycol ether)
10% Brÿ-30 emulsifier (polyoxyethylene lauryl ether aromatic mixture)
25% Shellsol A
35% liquid paraffin

6. Emulsion concentrate

30% of a compound of formula I.
5% calcium dodecylbenzenesulfonic acid (emulsifier)
10% Marlowet EF emulsifier
55% Shellsol A

7. Wettable powder

20% of a compound of formula I.
10% Ca lignin sulfonate (dispersant)
20% silica
25% northern white chalk
25% kaolin

Concentrates become 2nd, 3rd, 4th, 5th, 6th and 7th made by mixing with water spray liquors, which are generally between 0.001, preferably 0.01 and Contain 0.5% active ingredient.  

The following examples are intended to illustrate the invention explain without limiting their scope, in particular can the reaction conditions, such as temperature, solvent etc. can be modified within wide limits.

The processes A, B and C according to the invention are each explained in an example. In the in the The compounds described in the table are the procedures A to E specified according to which these substances are manufactured can be.

Example 1

m-cresols of formula II are known from the literature. (e.g. Raiford; J. Amer. Chem. Soc; 46 448 (1911), or Flaugh et al; J. Med. Chem; 2263 (1979).

The synthesis of 2-bromo-3-methyl-4-nitrophenol described:

2-bromo-3-methyl-4-nitrophenol

16.0 g of bromine in 10 ml of glacial acetic acid are at room temperature to a solution of 15.3 g within 30 minutes 3-methyl-4-nitrophenol added dropwise in 130 ml of glacial acetic acid. It is stirred for 1 h at room temperature and then at 50 ° C bath temperature in vacuum to ½ of the original Volume constricted. Then a lot of ice water is added. An organic phase forms with Diethyl ether is extracted.

The combined ether extracts are washed with water, dried over sodium sulfate and clarified with activated carbon. After the ether has been distilled off, an oil remains which crystallizes when rubbed with gasoline.
Yield: 17.5 g of 2-bromo-3-methyl-4-nitrophenol as crystals of melting point 92 ° C.

Example 2 (Method A) Methyl 2- (2-chloro-3-methyl-4-nitrophenyloxy) propionate

4.5 g of 2-chloro-3-methyl-4-nitrophenol potassium salt are heated on a water bath with 3.4 g of methyl 2-bromopropionate in 4 ml of dimethylformamide. After 20 min, the reaction mixture is poured into ice water and extracted with diethyl ether. The combined ether extracts are washed with 2N sodium hydroxide solution and then with water, dried over sodium sulfate and the solvent is distilled off in vacuo. There remains an oil which quickly crystallizes out at room temperature.
Yield: 5.2 g of methyl 2- (2-chloro-3-methyl-4-nitrophenyloxy) propionate, mp. 55-57 ° C.

Elemental analysis:
calc. C 48.30% H 4.42% N 5.13%
found C 48.51% H 4.39% N 4.93%

Example 3 (Method B) Propyl 2- (2-chloro-3-methyl-4-nitrophenyloxy) propionate

2.5 g of 2- (2-chloro-3-methyl-4-nitrophenyloxy) propionic acid are boiled with 2.00 g of N, N'-carbonyldiimidazole in 15 ml of tetrahydrofuran. After 15 minutes, 10 ml of n-propanol are added and the mixture is heated to boiling for a further 30 minutes. The reaction mixture is concentrated in vacuo, the residue is taken up in diethyl ether, washed with water and dried over sodium sulfate. After the solvent has been distilled off, an oil remains in which no contamination can be detected by thin-layer chromatography.
Yield: 2.9 g of propyl 2- (2-chloro-3-methyl-4-nitrophenyloxy) propionate as an oil.

Elemental analysis:
calc. C 51.90% H 5.35% N 4.66%
found C 51.93% H 5.50% N 5.00%

Example 4 (Method C) 2- (2-chloro-3-methyl-4-nitrophenyloxy) propionic acid-N, N-dimethylamide a) 2- (2-Chloro-3-methyl-4-nitrophenyloxy) propionic acid chloride

2.6 g of 2- (2-chloro-3-methyl-4-nitrophenyloxy) propionic acid are heated to boiling in 15 ml of thionyl chloride for 20 min. The excess thionyl chloride is in a vacuum distilled off. The 2- (2-chloro-3-methyl-4-nitrophenyloxy) propionic acid chloride remaining as residue can without further cleaning can be used.

b) 2- (2-chloro-3-methyl-4-nitrophenyloxy) propionic acid-N, N-dimethylamide

While stirring and cooling with ice, a solution of the acid chloride obtained in a) in 5 ml of chloroform is added dropwise to a solution of 1.0 g of dimethylamine and 1.6 g of triethylamine in 20 ml of acetonitrile. Then it is heated to boiling for 2 hours. The reaction mixture is poured into ice water and then extracted with diethyl ether. The combined ether extracts are washed with 2N sodium hydroxide solution and water and dried over sodium sulfate. After the solvent has been distilled off, an oil which crystallizes at room temperature remains.
Yield: 1.95 g of 2- (2-chloro-3-methyl-4-nitrophenyloxy) propionic acid-N, N-dimethylamide, mp. 115 ° C.

Elemental analysis:
C 50.27% H 5.27% N 9.77%
found C 50.38% H 5.05% N 9.82%

Example 4a (Method E) Ethyl 2- (2-chloro-3-methyl-4-nitrophenoxy) propionate

5.1 g (0.02 mol) of ethyl 2- (3-methyl-4-nitrophenoxy) propionate, 1 spatula tip 2,2′-azoisobutyronitrile and 1 spatula tip of iodine in 50 ml carbon tetrachloride solved. Under exposure to a 200 W lamp, at Chlorine introduced at room temperature for 2 hours. You narrow and cleans the residue on a silica gel column (Eluent diisopropyl ether). 3.5 g (61% of theory) are obtained of a yellowish oil.  

Example 5 Optically active ethyl 2- (2-chloro-3-methyl-4-nitrophenyloxy) propionate

2.25 g of 2-chloro-3-methyl-4-nitrophenol potassium salt are left with 2.72 g of 1-O- (p-toluenesulfonyl) lactic acid ethyl ester in 7.5 ml of dimethylformamide at 80 ° C. After 30 min the reaction mixture is poured into ice water and extracted with diethyl ether. The combined ether extracts are first washed with 2N sodium hydroxide solution and with water, dried over sodium sulfate and concentrated. The remaining oil is purified on silica gel with diisopropyl ether / gasoline (2: 1).
Yield: 2.0 g of optically active ethyl 2- (2-chloro-3-methyl-4-nitrophenyloxy) propionate as an oil with [ α ] + 20.6 (in ethanol).

Elemental analysis:
C 50.2% H 4.2% N 4.9%
found C 50.6% H 5.0% N 5.3%

Table I

Claims (7)

1. α -phenoxycarboxylic acids and their derivatives of the formula which also includes the stereoisomeric compounds which can be derived therefrom in any mixture or in pure form, and optionally their salts with mono-, di- or trivalent cations, where X or Y is halogen
R¹ is hydrogen or C₁-C₄ alkyl
Z for the rest is in which n can take the values 0 to 2 R¹ is as previously defined and may be the same or different
or for the rest in which R² is hydrogen, C₁-C₁₀ alkyl, alkoxyalkyl having up to 4 carbon atoms, an alkenyl group having up to 6 carbon atoms or an alkynyl group having up to 6 carbon atoms
or for the rest is in which R³, R⁴ which may be the same or different is hydrogen, C₁-C₆-alkyl or together represents a - (CH₂) _m group with m = 4 to 6. 2. Compounds according to claim 1, characterized in that X or Y is fluorine, chlorine or bromine
R¹ is hydrogen, methyl or ethyl
Z for the rest stands in which n can assume the values 0 to 2 R 1 is as previously defined and can be the same or different
or for the rest is in which R² is hydrogen, C₁-C₈ alkyl or ethoxyethyl
or for the rest is in which R³, R⁴ which may be the same or different is hydrogen, C₁-C₄-alkyl or together represents a - (CH₂) _m group with m = 4 to 6. 3. Herbicidal agent, characterized in that it is considered Active ingredient at least one compound according to claim 1 to 2 contains. 4. Use of compounds according to claim 1 to 2 the control of undesirable plant growth. 5. A process for the preparation of compounds according to claim 1 to 2, characterized in that in a manner known per se

• a) a phenol or phenol ion of the formula with a compound of the formula is implemented, where X, Y, R¹ and Z have the abovementioned meaning, M represents hydrogen or any cation and W represents a nucleophilically exchangeable group, or that
• b) Compounds of formula I with Z = COOH with alcohols of the formula R² OH (IV) or amines of the formula HNR³R⁴ (V) to carboxylic acid esters of the formula I with Z = COOR² or carboxamides of the formula I with Z = CONR³R⁴ or that
• c) carboxylic acid halides of the formula with alcohols of the formula R2 OH (IV) or amines of the formula HNR³R⁴ (V) to carboxylic acid esters of the formula I with Z = COOR² or carboxamides of the formula I with Z = CONR³R⁴ or that
• d) compounds of the formula with carboxylic acids or carboxylic acid derivatives of the formula I or VI to give 2 [ α- phenoxyalkyl] oxazolines of the general formula I with cyclized or aldehydes of the formula with a compound of the formula to the corresponding 2 [ α- phenoxy-alkyl] -oxazoline of the general formula I with cyclized or that one
• e) compounds of the formula nitrided
  or compounds of the formula halogenated
  or compounds of the formula in which one of the substituents X ′ or Y ′ for an amino group, the other for hydrogen, is converted into the corresponding α- halophenols of the formula I.

and that, if desired, an initially obtained carboxylic acid of formula I (Z = COOH) in a salt, one initially obtained salt converted into the free acid.   6. The method according to claim 5 for the production of optically active compounds of formula I, characterized in that that at one of the procedural stages of the process a) to e) an optically active starting material is used becomes.