CA1176637A - 2-substituted phenoxy-3-chloro-5-trifluoromethyl pyridine useful as a herbicide - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
2-substituted phenoxy-3-chloro-5-trifluoromethyl pyridlne~ having the formula (I):

(II) wherein X is a hydrogen atom; a (C1-C4)alkyl group; a (C1-C4) alkoxy group; a -COOR1 group wherein R1 is a hydrogen atom, a a cation or a (C1-C4)alkyl group; or an

Description

~,~7~3~7 The present invention relates to 2-substituted phenoxy-3-chloro-5-trifluoromethyl pyridines having herbicidal properties and a herbicidal composition containing the same.
The present invention provides a 2-substitued phenoxy-3-chloro-5-trifluoromethyl pyridine having the formula (I):

CQ

3 ~ r ~ ~ (I) N X

wherein X is a hydrogen atom; a (Cl-C4)alkyl group; a (Cl-C4) alkoxy group; a -COORl group wherein Rl is a hydrogen atom, a cation or a (cl-C4)alkyl group~ or an lCH3 group wherein R2 is a hyd~ogen atom, a cation, a (Cl-C4)alkyl group or a benzyl group and Y is a halogen atom, a nitro group or a cyano group.
The invention further provides a herbicidal composition ~comprising a herbicidally effective amount of at least one com-~pound of the above general formula (I) and agriculturally accep-~20 table adjuvants~
In formula (I), suitable examples of the halogen atoms which may be employed as substituent Y include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. Suitable ~ examples of the alkyl moiety in the (Cl-C4)alkyl groups or (Cl-; C4)alkoxy groups which may be employed as substituent ~, Rl and R2 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group and a tert-butyl group. Suitable examples of the cations which may be employed as substituent Rl and R2 include an alkali 3Q metal ion such as sodium ion and potassium ion, an ammonium ion, and an organic ammonium ion such as dimethyl ammonium ion and diethanol ammonium ion.

~P

~L~Il7~3~

Of the compounds of the formula (I), it is particularly preferred for X to be a -COORl group wherein Rl is a hydrogen atom, a cation or a (Cl-C4)alkyl group, and an ICH3 group wherein R2 is a hydrogen atom, a cation, a (Cl-C4)alkyl group or a benzyl group, and for Y to be a halogen atom, a nitro group or a cyano group.
The compounds ofthe present invention of the formula (I) can be produced by the methods described below.
METHOD A
A 2-halo-3-chloro-5-trifluoromethyl pyridine of the formula (II): CQ
.
CF ~ ~ Hal 3 \ . (II) wherein Hal is a halogen atom, and a substituted phenol of the formula (III):

HO ~ / \ ~ y ~ ~ ~ (III) X
wherein X is a hydrogen atom; a (Cl-C4)alkyl group; a (Cl-C4) alkoxy group; a -COORl group wherein Rl is a hydrogen atom, a - CH
cation or a tCl-C4)alkyl group; or an 1 3 group wherein R2 is a hydrogen atom, a cation, a tCl-C4)alkyl group or a benzyl group, and Y is a halogen atom, a nitro group or a cyano group, are reacted in the presence of an alkaline material at a temperature of 10 to 180C, preferably 50 to 150C, for 1 to 20 hours, preferably 1 to 10 hours, to form the compound of the 3~ formula (I):

`37 CQ

~ ~ (I) wherein X and Y are the same as defined hereinbefore.
The starting materials described in the above method, i.e. the 2-halo-3-chloro-5-trifluoromethyl pyridine of the formula (II) is described in, for example DT-OS 2,812,607, and the substituted phenol of the formula (III) is described in, for examplelBritish Patent 1,390,295.
Suitable examples of the alkaline materials which can be u~ed in the above described method are alkali metal hydroxides,~
such as sodium hydroxide or potassium hydroxide, and alkali metal carbonates~such as sodium carbonate or potassium carbonate.
; ~ Polar aprotic solvents/such as dimethyl sulfoxide, dimethyl ~formamide, hexamethylphosphoramide or sulfolane can be used in the above described method as a solvent.

.
Certain compounds of the present invention can be also ~ produced by the~following method with industrial advantages.

20~ METHOD B

~ nitration, halogen-;~ ation or cyano- CQ
CQ genation p ~ o ~ (~V)- - > CF3 ~ 0 ~ Y (V) OH OH

: ~ . I /
V) + Hal-CHcOoR2 (VI) ~~~~ CF3 ~ ~ CH3 In the reaction formula, Y is a halogen atom, nitro group or cyano group; Hal. is a halogen atom; R2 is a hydrogen atomr~ a cation, a (Cl-C4)alkyl group or benzyl group. The com-pound of the formula (IV) can be produced by:reacting 2-halo-3-chloro-5-trifluoromethyl pyridine of the formula (II) with resor-cinol by the Method A.

~L7~3'7 The compound of the formula (VI) is a known cornpound described for example in U.S. Patent 4,046,553.
METHOD C:
Cl CF3 ~ 0 ~ (VII-1 ~ C

~ 7 C~ - ~ ~ (VIII) CF3 ~ ~ (VII-2~ COOH
CN

nitration, halogenation or C
(VIII) cyanogenation CF3~ ~ Y
`COOH

In the reaction formula, Y is a halogen atom, nitro group or cyano group. The compounds of the formula (VII-l) and ~(VII-2) can be respectively produced by reacting 3-methyl phenol or 3-cyano phenol with 2-halo-3-chloro-5-trifluoromethyl pyridine ~20~ ~ of the formula (II) by Method A.
The present invention will be further illustrated by way of the following Examples.
Preparation Example l:

2-(4-chlorophenoxy)-3-chloro-5-trifluoromethyl pyridine:
In a flask, 4.0 g of 2,3-dichloro-5-trifluoromethyl pyridine, 10 ml of dimethyl sulfoxide, 5.1 g of anhydrous potas-sium carbonate and 2.g~ g of p-chlorophenol were charged. The flask was heated in an oil bath at 110C with stirring for 2 hours. The completion oE reaction was confirmed by a gas chro-matography. The reaction mixture was cooled and poured into a suitable amount of water. The reaction product was extracted d ~ ~t~ ~

with methylene chloride and the extracted phase was washed with a dilute aqueous sodium hydroxide solution and then, with water and dried over anhydrous sodium sulfate. Methylene chloride was distilled off under a reduced pressure and the oily residue was distilled to obtain 4.4 g of the object compound having a boiling point of 124-127C/2.5 mm~g.
Preparation Example 2-2-(4-nitrophenoxy)-3-chloro= 5-trifluoromethyl pyridine:
In a flask, 64 g of 2,3-dichloro-5-trifluoromethyl pyridine, 250 ml of dimethyl sulfoxide, 81.8 g of anhydrous potassium carbonate and 33.4 g of phenol were charged. The flask was heated in an oil bath at 100C with stirring for 4 hours. The reaction mixture was poured into a suitable amount of water and the reaction product was extracted with methylene chloride. The extracted phase was washed with water, with a 5%
aqueous sodium hydroxide solution and then, with water and dried over anhydrous sodium sulfate. Methylene chloride was distilled off under a reduced pressure and the residue was distilled to obtain 49 g of 2-phenoxy-3-chloro-5-trifluoromethyl pyridine.
~ The product was mixed with 100 ml of 98% sulfuric acid and the mixture was cooled with ice water. A mixture of 11.3 g of 60~
nitrlc acid and 30 ml of 98% sulfuric acid was added dropwise to the sulfuric acid solution of the reaction product at a temper-ature of 0 to 10C. A mild exothermic reaction was performed.
After the reaction, the reaction mixture was poured into a suitable amount of ice water and neutralized with a 10~ aqueous sodium hydroxide solution. The reaction product was extracted with methylene chloride. The extracted phase was dried over anhydrous sodium sulfate. Methylene chloride was distilled off under a reduced pressure to obtain 3~.5 g of the object compound having a melting point of 90 to 91C.

~L1'7~3~

Preparation Example 3:
Meth~ 2-nitro-5--(3-chloro-5-trifluoro-methyl-2-pyridyloxy)benzoate:
The process of Preparation Example 2 was repeated except using 51 g of methyl 3-hydroxy benzoate instead of 33.4 g of phenol, to obtain 50 g of methyl 3-(3-chloro-5-trifluoro-methyl-2-pyridyloxy)benzoate. Then, 5 g of -the resulting com-pound was mixed with 20 ml of 98% sulfuric acid and the mixture was maintained at a temperature of lower than 5C. A mixture of 1.4 g of 70% nitric acid and 5 g of 98% sulfuric acid was added dropwise to the reaction mixture. After a completion of the exothermic reaction, the reaction mixture was stirred at room temperature for 30 minutes. In accordance with the process of Preparation Example 2, the extraction, the washin~ and the drying were carried out to obtain 1.0 g of the object compound having a melting point of 56 to 57C.
Preparation Example 4:
Sodium 2-nitro-5-(3-chloro-5-trifluoromethyl-2-pyridyloxy)benzoate:
Methyl 2-nitro-5-(3-chloro-5-trifluoromethyl-2-pyridyl-oxy~)benzoate was hydrolyzed to obtain 2-ni-tro-5-(3-chloro-5-tri-fIuoro-methyl-2-pyridyloxy)benzoic acid. Then, 350 mg of the product was dissolved in 3 ml of isopropyl alcohol. The solution was admixed with a solution of 40 mg of sodium hydroxide in 1 ml of water. The mixture was stirred at room temperature ~or 30 minutes. The solvent was distilled off under a reduced pressure to obtain 350 mg of a crude object compound.
Preparation Example 5:
Ethyl 2-[2-bromo-5-(3-chloro-5=trifluoromethyl-2-pyridyloxy)phenoxy]propionate:
In 150 ml of chloroform, 5.5 g of 2-(3-hydroxyphenoxy)-

3-chloro-5-trifluorome-thyl pyridine was dissolved and then, 3.5 g 6;~
of bromine was added dropwise to the solution at a temperature of 10 to 15C. After the reaction, the reaction product was washed with water, with an aqueous sodium bicarbonate solution, with a saturated sodium thiosulfate solution and then, with water and dried over anhydrous sodium sulfate. Chloroform was distilled off under a ~educed pressure and the resulting crystals were washed with hexane and dried to obtain 3.0 g of 2-(3-hydroxy-

4-bromophenoxy)-3-chloro-5-trifluoromethyl pyridine having a melt-ing point of 124 to 127C.
In 30 ml of methyl ethyl ketone, 2.9 g of the resulting product and 1.42 g of ethyl 2-bromopropionate were dissolved and then, 2.2 g of anhydrous potassium carbonate were added. The mixture was refluxed for 3 hours. After the reaction, the solvent ; was distilled off under a reduced pressure. The residue was ; poured into a suitableamount of water and the product was extractedwith methylene chloride. The extracted phase was washed with water and dried over anhydrous sodium sulfate. Methylene chloride was distilled off and 3.5 g of the resulting oily product was adsorbed in a silica gel column and developed and eluted with toluene to obtain 2.4 g of the object compound (nlD 1.5440).
Preparation Example 6:
Ethyl-2-[2-cyano-5-(3-chloro-5-trifluoromethyl-2-pyridyloxy)phenoxy]propionate:
A mixture of 1 g of ethyl 2-[2-bromo-5-(3-chloro-5-trifluoromethyl-2-pyridyloxy)phenoxy]propionate, 0.3 g of cuprous cyanide and 3 ml of dimethylformamide was refluxed for 5 hours.
After the reaction, the reaction mixture was poured into a suitable amount of water containing dissolved ferric chloride. The pro-duct was ex-tracted with methylene chloride. The extracted solu-tion was washed with water and dried over anhydrous sodium sulfate.
The solvent was distilled off under a reduced pressure. The resulting oily product was adsorbed in a silica gel column and ~7~}~

developed and eluted with a mixture of n-hexane, toluene and methylene chloride to obtain 0.2 g of the object compound having a boiling point of 163 to 165C/0.5 mmHg.
Preparation Example 7:
, Ethyl 2-[2-nitro 5-(3-chloro-5-trifluoromethyl-2-pyridyloxy)phenox~]propionate:
2,3-Dichloro-5~trifluoromethyl pyridine was condensed with resorcinol and the product was nitrated with a mixed acid of ni-tric acid and sulfuric acid to obtain 2-(3-hydroxy-4-nitro-phenoxy)-3-chloro-5-trifluoromethyl pyridine. In 10 ml of methyl ethyl ketone, 1.67 g of the resulting product and 1.09 g of ethyl 2-bromopropionate were dissolved and then, 1.38 g of anhydrous potassium carbonate were admixed. The mixture was refluxed with stirring for 4 hours. After the reaction, a small amount of water was added to the reaction mixture. The solvent was dis-tilled off and the product was extracted with methylene chloride.
The extracted phase was washed with water and dried over anhydrous sodium sulfate. Methylene chloride was distilled off. The resulting oily product was adsorbed in a silica gel column and developed and eluted with toluene to obtain 0.8 g of the object compound (nD 1.5337~.
Typical examples of the compounds of the formula (I) of the present invention are given below:

3'7 Compound No. X Y Physical Constant . _ . . .
H CN mp 64-66C
2 H NOz mp 90 - 91C
3 -OCH3 NOz nlD 1.5680 4 -COOCH3 No2 mp 56 - 57C
-COOH N02 mp 124-128C
l~3 15 6 -ocHcooc2Hs No2 nD 1.5337 7 -OCHCOOC2Hs Br nD 1.5440 3 -OCHCOOCH2~ Br nD5 1.5646 (~H3 9 -OCHCOOCH2~ CN bp 175-177C/
1.5 mmHg H Cl bp 124-127C/
Z,5 mmHg 11 CH3 NO2 bp 173-180C/

5 mmHg 1~ cooc4Hg(n) No2 bp 185-188C/
2 mmHg 13 -COONa NO2 mp 200 - 210C
(~H3 14 -OCHCOOC4Hg(n) No2 bp 168 -17ZC/
CH3 1. lmmHg -OCHCOOH Br mp 115 - 118 C
:20 CH3 16 -o~Hcooc2H5 CN bp 163-165C/
0.5 mmHg 17 -COOK NO2 mp 150 - 180C
The compounds having the formula (I) of the present invention have an excellent herbicidal effect when they are used as active ingredients in herbicidal compositions as shown in the following Test Examples. The compounds having the formula (I) ; wherein X is -COORl group, are very effective for killing noxious weeds without any phytotoxicity to soybean. The compounds having the formula (I) wherein X is -OCHCOOR2 group are very effective for killing noxious weeds without any phyto-toxicity to corn and wheat. The compounds of formula I can be applied by a foliage treatment or a soil treatment to weeds and can be applied to paddy fields, up-land farms, orchards, and fores-ts. The compounds of ormula I can be applied in the form of aqueous solution or aqueous dispersion prepared by dissolving or dispersing the compound in water. The compounds of formula I
can be also used in t~e form of emulsifiable concentrates, wettable powder, water miscible solution, dusts and granules which are prepared by mixing the compound with an agricultural adjuvant. Suitable agricultural adjuvants include solid carriers such as diatomaceous earth, calcium hydroxide, calcium carbonate, talc, whitecarbon, kaolin, bentonite and Jeeklite (Trade mark for a zeolite produced by Jeeklite Co.); and solvents such as - n-hexane, toluene, xylene, solvent naphtha, ethanol, dioxane, acetone, isophorone,methyl isobutyl ketone, dimethylformamide, dimethylsulfoxide and water; and anionic or nonionic surface active agents such as sodium alkylsulfate, sodium alkylbenzene-sulfonate, sodium ligninsulfonate, polyoxyethylene lauryl ether, polyoxyethylene alkyl aryl ether, polyoxyethylene fatty acid ester and polyoxyethylene sorbitan fatty acid ester. These ; adjuvants can be selected as desired to prepare the herbicidal composition. The herbicidal compositions usually comprise 1 to 90 wt. %, preferably 1 to 70 wt. % of the active ingredient; 5 to 99 wt. %,preferably 25 to 99 wt. % of the carrler or the sol-vent and 0 to 30 wt. %~preferably 1 to 20 wt. % of the surface active agent. The active ingredient can be combined with other agricultural chemicals such as other herbicides, insecticides, fungicides or fertilizers or soils. In some cases a synergistic effect may be obtained.
The suitable amount of the herbicide of formula I
depends inter alia upon the conditions of weather or soil, form of the composition, time of application, method of application ~7~
and types of weeds, and is usually in a range of 0.1 to 100 g preferably 0.5 to 70 ~ per are as an active ingredient.
Test Example 1:
Each of a plurality of pots of 1/5,000 are (are=100 m ) was filled with a paddy soil and the soil was supersaturated with water. Seeds of edible barnyard grass were sown in each pot and covered with soil. The barnyard grass was sprouted in up-land conditions and then it was grown in flooded conditions of a depth of 3 cm. Each aqueous dispersion of each active ingredient di-luted with water was poured into the pot at the predetermined ratio when its coleoptile had appeared.
Three weeks after the treatment, the growth conditions of weeds were observed. "Degree of growth control" is shown by 5 ratings as the following standards.
5: Complete growth suppression is found, 4: Remarkable growthsuppression is found;
3: About 60% growthsuppression is found;
2: About 30~ growth suppressionis found;
1: No apparent difference between treated plants and untreated ~20 plants is found.
The result is shown in Table 1.
note. Herbicidal composition; Emulsifiable concentrate prepared by uniformly mixing 20 wt. parts of each active ingredient, 60 wt.
parts of xylene and 20 wt. parts of Sorpol 2806 B (Trade mark for a mixture of a polyoxyethylene phenyl phenol derivative, a poly-oxyethylene alkylaryl ether, a polyoxyethylene sorbitan alkylate a~d an alkylaryl sulfonate produced by Toho Chemical Co., Ltd.

3~

Table 1 .
. _ Degree of growth control Active Amountofactiveingredient ingredient 5(~/are) 2 5(g/are) ~L
Test Example 2:
Each of a plurality of pots of 1/3,000 are was filled ~ith an up-land soil. Seeds of barnyard grass were sown in the pot and covered with up-land soil containing seeds of large crab-grass, Lady's thumb to a depth of about 1 cm.
Two days after the sowing, an aqueous dispersion of each active ingredient diluted with water (the dispersion used in Test Example 1) was sprayed into the pot.
Thirty days after the treatment, the growth condition ~: of weeds were observed. The results are shown in Table 2.
::
"Degree of growth control" is shown by 10 ratings as the follow-ing standards.
lQ: Complete growth suppression is found;
1:. No apparent difference between treated plants and untreated plants is found.

~L~7~3~7 Table 2 ___ Amount of Degree of growth co_trol Active active BarnyardLargeLady' s ingredient ingredient grass crab- thumb ( g/ are) grass Compound No, 3 100 10 10 10 " _ -100 10 10 _ 7 10 10 ll -1-00 10 10 10 " 8 100 8 10 " 16 100 10- 10 10 ll 50 _ 8 10 10 ll 100 10 10 10 " 5 100 lO - 10 - 10 " 1 1 100 10 10 ' 10 " 12 100 10 10 10 _ 8 _ 10 " 13 100 10 10 10 " 14 100 10 10 10 " 15 10`0 9 10 _50 7 8 10 :
~ ~ 20 : ~ :
Test Example 3:
~; Each of a plurality of pots of 1/3, 000 are was filled ~ ::
wi-th soil to be in an up-land culturP condition. Seeds of crop plants of soybean, wheat, cotton and corn and weeds o f Large crab-grass, Redroot, pigweed, Common lambsquarters and Lady's thumb were sown and covered with soil to a depth of about l cm.
Three days after the sowing, each aqueous dispersion of each active ingredient diluted with wa~er (the dispersion used in Test Example 1) was sprayed at a ratio of 5 g/are of the 3 0 active ingredient .
Thirty days after -the treatment, the growth condition 7~ 7 of the crop plants and weeds was observed and "Degree of growth control" is shown by the rating of Test Example 2. The result is shown in Tahle 3.

Table 3 Degree of growth control Active Crop plant Weed ingredient A B C D E F G LH
Compound No. 3 1 1 2 1 6 10 6 _ " ~ 1 2 2 1 9 10 10 6 ~ - 16- 1 2 1 6 10 1~ 6 3 2 3 2 . 9 10 10 10 " 12 1 2 1 1 6 10 10 _ '' 15 1 1 . 1 1 6 8 9 6 : ~ note:
A: soybean B: wheat C: cotton D: - Corn ;~ E: Large crab-grass F: Redroot pigweed G: .Common lambsquarters ; ~20~ ; H: Lady's thumb Test Example 4:
Each of a plurality of pots of l/5, 000 are was filled with soil to be in an up-land culture condition. Seeds of the crops and weeds shown in Table 4 were sown. At the time of the growth of the plants of unifoliate stage. of soybean, two leaf stage of corn, 3 leaf stage of wheat, and two leaf stage of Redroot pig-weed, common lambsquarters and Lady ' s thumb and 2 . 5 leaf stage of common groundsel, each aqueous dispersion of each active ingredient diluted with 4 . 5 liters per are was sprayed in foliage treatment .

63~

Twenty five days after the treatment, the growth condl-tion of the crop plants and weeds was observed and "Degree of growth controlll is shown by the rating of Test Example 2. The result is shown in Table 4.

Table 4 _ ~A~nount _ _ Active ofactive Degree of growth control ingredient ingredient Cro )plant ~eed (g/are) I J K L M N ¦ O
. _ _ .
~ornpound No. 13 5 2 _ _ 1010 10 10 No, 15 ¦ 2.5 _ 2 1 1010 10 10 note:

I: soybean;
J: corn;
K: wheat;
L: Redrootpigweed M: Com monlambsquarters;
N: Lady's thumb;
O: Com mon groundsel ~erbicidal composition, Wettable powder prepared by uniformly mixing each active ingredient with the adjuvant at a ratio of 4 : l. The adjuvant was a mixture of 78 wt. parts of ~Jeeklite, 2 wt. parts of Lavelin S (Trade mark for a sodium naphthalene, sulfonate-formaldehyde condensate produced by Daiichi Kogyo Seiyaku Co., Ltd.) 5 wt. parts of Sorpol 5039 tTrade mark for a sulfate of polyoxyethylene alkylaryl ether produced by Toho Chemical Co., Ltd.) and 15 wt. parts of Carplex (Trade mark for whitecarbon (SiO2 nH2O) produced by Shionogi Seiyaku Co., Ltd.) Typical compositions will be illustrated.
Composition l:
(1) Ethyl 2-[2-nitro-5-(3-chloro-5-trifluoromethyl-2-pyridyloxy) phenoxy]propionate 20 wt. parts ~7~3~
(2) Xylene 60 wt. parts (3) Sorpol 2806B 20 wt. parts The components (1)-(3) were uniformly mixed to give an emulsifiable concentrate.

Composition 2:
-(1) Jeeklite 78 wt. parts (2) Lavelin S 2 wt. parts (3) Sorpol 5039 5 wt. parts (4) Carplex 15 wt. parts The mixture of these components (1)-(4) was mixed with potassium 2-nitro-5-(3-chloro-5-trifluoromethyl-2-pyridyloxy) benzoate at a ratio of 4:1 by weight to give a wettable powder.
Composit n 3:
(1) 2-[2-nitro-5-(3-chloro-5-trifluoromethyl-2-pyridyloxy)phenoxy]
- propionic acid 20 wt. parts (2) ~eeklite 75 wt. parts (3) Sodium lignin sulfonate 3 wt. parts (4) ~avelin S 2 wt. parts The components (1)-(4) were uniformly mixed to give a wettable powder.
Composition 4:
(1) Sodium 2-nitro-5-(3-chloro-5-trifluoromethyl-2-pyridyloxy) benzoate 20 wt. parts (2) Water 80 wt. parts The component (1) was dissolved in water to give a solu-tion.
Composition 5:

(1) Bentonite 58 wt. parts (2) Jeeklite 30 wt. parts (3) Sodi~m lignin sulfonate5 wt. parts The components (1)-(3) were mixed and granulated. A
solution of 7 wt. parts of methyl 2-nitro-5-(3-chloro-5-trifluoro-~17~

methyl-2-pyridyloxy)benzoate in acetone was sprayed on the granu-lated components to give a granulate.

1() .~

0:

:~:

Claims (29)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A compound having the general formula (I):

wherein X is a hydrogen atom; a (C1-C4)alkyl group; a (C1-C4) alkoxy group; a -COOR1 group wherein R1 is a hydrogen atom, a cation or a (C1-C4)alkyl group; or an group wherein R2 is a hydrogen atom, a cation, a (C1-C4)alkyl group or a benzyl group; and Y is a halogen atom, a nitro group or a cyano group.

2. The compound of claim 1, wherein X is a -COOR1 group wherein R1 is a hydrogen atom, a cation or a (C1-C4)alkyl group and Y is a halogen atom, a nitro group or a cyano group.

3. The compound of claim 1, wherein X is a -COOR1 group wherein R1 is a cation, and Y is a nitro group or a cyano group.

4. The compound of claim 1, wherein X is an group wherein R2 is a hydrogen atom, a cation, a (C1-C4)alkyl group or a benzyl group, and Y is a halogen atom, a nitro group or a cyano group.

5. The compound of claim 1, wherein X is a group wherein R2 is a (C1-C4)alkyl group, and Y is a nitro group or a cyano group.

6. The compound of claim 1 which is sodium 2-nitro-5-(3-chloro-5-trifluoromethyl-2-pyridyloxy)benzoate.

7. The compound of claim 1 which is methyl 2-nitro-5-(3-chloro-5-trifluoromethyl-2-pyridyloxy)benzoate.

8. The compound of claim 1, which is ethyl-.alpha.-[2-nitro-5-(3-chloro-5-trifluoromethyl-2-pyridyloxy)phenoxy]propionate.

9. The compound of claim 1, which is n-butyl .alpha.-[2-nitro-5-(3-chloro-5-trifluoromethyl-2-pyridyloxy)phenoxy]pro-pionate.

10. The compound of claim 1 which is ethyl .alpha.-[2-cyano-5-(3-chloro-5-trifluoromethyl-2-pyridyloxy)phenoxy]propionate.

11. A method of killing noxious weeds which comprises applying thereto at least one compound having the general formula (I):

(I) wherein X is a hydrogen atom; a (C1-C4)alkyl group; a (C1-C4) alkoxy group, a -COORl group wherein R1 is a hydrogen atom, a cation or a (Cl-C4)alkyl group; or an group wherein R2 is a hydrogen atom, a cation, a (C1-C4)alkyl group or a benzyl group; and Y is a halogen atom, a nitro group or a cyano group.

12. A method of claim 11, wherein X is a -COOR1 group wherein R1 is a hydrogen atom, a cation or a (C1-C4)alkyl group, and Y is a halogen atom, a nitro group or a cyano group.

13. The method of claim 11, wherein X is a -COOR1 group wherein R1 is a cation, and Y is a nitro group or a cyano group.

14. The method of claim 11, wherein X is an group wherein R2 is a hydrogen atom, a cation, a (C1-C4)alkyl group or a benzyl group, and Y is a halogen atom, a nitro group or a cyano group.

15. The method of claim 11, wherein X is an group wherein R2 is a (C1-C4)alkyl group, and Y is a nitro group or a cyano group.

16. The method of claim 11, wherein the compound is sodium 2-nitro-5-(3-chloro-5-trifluoromethyl-2-pyridyloxy)benzoate.

17. The method of claim 11, wherein the compound is methyl 2-nitro-5-(3-chloro-5-trifluoromethyl-2-pyridyloxy)benzO-ate.

18. The method of claim 11, wherein the compound is ethyl .alpha.-[2-nitro-5-(3-chloro-5-trifluoromethyl-2-pyridyloxy) phenoxy]propionate.

19. The method of claim 11, wherein the compound is n-butyl .alpha.-[2-nitro-5-(3-chloro-5-trifluoromethyl-2-pyridyloxy) phenoxy]propionate.

20. The method of claim 11, wherein the compound is ethyl .alpha.-[2-cyano-5-(3-chloro-5-trifluoromethyl-2-pyridyloxy) phenoxy]propionate.

21. A process for preparing a compound of formula A:

A

wherein Q is selected from: hydrogen; a cation; and an alkyl containing 1 to 4 carbon atoms which comprises reacting a com-pound of the formula B:

B

wherein Hal is a halogen atom with a compound of formula D:

D

wherein Q is as defined above in the presence of a base, and recovering the desired product.

22. A compound having formula A;

A
wherein Q is selected from: hydrogeni a cation; and alkyl con-taining 1 to 4 carbon atoms.

23. A method of killing noxious weeds which comprises applying thereto a herbicidally effective amount of a compound of formula A as set forth in claim 22.

24. A compound having the formula:

25. The method of claim 23 wherein the compound applied is the compound claimed in claim 24.

26. A compound having the formula:

27. The method of claim 23 wherein the compound applied is the compound claimed in claim 26.

28. A compound having the formula:

29. The method of claim 23 wherein the compound applied is the compound claimed in claim 28.