CA1267296A - 2-(1-(3-chloroallyloxyamino) alkylidene)-5- alkylthioalkylcyclohexane-1,3-dione herbicides - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Herbicidal compositions are described wherein the active component is 2[1-(3-trans-chloroallyloxyamino)-propylidene]-5-(2-ethylthiopropyl)cyclohexane-1,3-dione, of the formula

Description

BACKGROUND OF THE INVENTIO~
This invention relates to herbicidal compositions containing trans-2-~1-(3-chloroallyloxyamino) propylidene]-5-(2-ethylthiopropyl)cyclohexane-1,3-dione and salts thereof.
In Canadian Patent Application No. 389,584 filea November 6th, 1981 are disclosed compounds having the formula:

R ~NO-R

O ~ OR

wherein R is alkyl of 1 to 6 carbon atoms or phenyl;
Rl is haloalkyl of 1 to 6 carbon atoms, haloalkenyl of 2 to 6 carbon atoms, haloaryl of 6 to 10 carbon atoms, halobenzyl, all of which contain 1 to 3 halogen atoms; cycloalkyl oE 5 to 7 carbon atoms, or benzyl substituted with 1 to 3 alkyl groups of 1 to 4 carbon atoms or haloalkyl groups of 1 to 4 carbon atoms and 1 to 9 halogen atoms;
R2 and R3 are independently hydrogen, alkyl of l to 3 carbon atoms, or alkylthio of 1 to 6 carbon atoms;
R4 is hydrogen, or carbalkoxy of 2 to 4 carbon atoms;
R5 is hydrogen, a cation, or -COR6 wherein R6 is alkyl of 1 to 6 carbon atoms or aryl oE 6 to 10 carbon atoms.
Further, in Canadian Application 438,123 filed September 30th, 1983, are also disclosed compounds of the formula : .

2 --R ~ ~NO~
O ~ OR

~R4 ~ \ 3 in which:
R represents a propyl group Rl represents a trans 3-chloroallyl or 4 chlorobenzyl group;
R2 represents hydrogen;
R3 represents a 2-ethylthiopropyl group;
R4 represents hydrogen;
R5 represents hydrogen, a cation, or the group -COR6 wherein R6 is alkyl of 1 to 6 carbon atoms.
These compounds are shown to exhibit herbicidal activity against grasses and are safe with respect to broad-leaf crops.
SUMMARY OF THE INVENTION
It has now been discovered that herbicidal composi-tions in which the herbicidally active compound has the Eorm-ula

3 ~ ~C
0~
~J

: CH3 wherein Rl is a 3-trans-chlorallyl group, and which may be called 2-[1- (3 transchloroallyloxyamino)propylidene~-5-(2-ethylthio-propyl) cyclohexane-1,3-dione e~hibit surprisingly superior herbicidal activity, as compared with other compounds of this class, even the homolog butylidene compound of Application ~7`~

No. 438,123. This is especially surprising because such homolog where R is propyl i5 a very good herbicide.
As well as exhibiting pre-emergence activity, the compositions of this invention exhibi-t excellent post-emergence herbicidal activity against Bermudagrass, foxtail, crabgrass, volunteer corn, volunteer sorghum, barnyardgrass, broad-lea~
signalgrass, goosegrass, red rice, sprangletop, seedling Johnsongrass and Rhizone Johnsongrass.
The compositions of this invention also exhibit excellent phytotoxicity against grasses at even very low appli-cation rates and may he safely applied with respect to broad-leaf crops at such rates. Thus, the compositions are especially useful for controlling grassy weeds in broad-leaf crops and are especially useful to control grassy weeds in soybean crops.
The active compound of the compositions of this invention can be represented by the following formula (I) NOR
CH3CH2C~
0~ ~ O~I
(I) (~ 3 El CH2cHscH2cH3 wherein Rl is 3-transchloroallyl.
The compound may be used in the compositions of this invention in the free form, or as an agrochemically acceptable salt thereof.
As is well recognized, compounds of the nature of Formula (I) exist as tautomers. The compounds also have two asymmetric carbon atoms and can also exist as optical isomers.

The above formula is intended to encompass the respective taut-omeric forms as well as the individual optical isomers as well as mixtures there~f.
The compositions oE this invention thus broa~ly con-sist of a compound of formula I, or an agrochemically accept-able salt thereof, together with a compatible agriculturally acceptable carrier. The amount used in such a composi~ion will depend in large part on the purpose for which the composition is intended to be used.
The present invention also provides a method for pre-venting or controlling the growth of unwanted grassy vegeta-tion, which comprises treating the growth medium and/or the foliage of such vegetation with a herbicidally effec~ive amount of a composition of the inventlon, or mixtures thereof.
The present invention also provides a method ~or regulating plant growth which comprises treating the growth medium and/or the foliage of such vegetation with a plant growth regulating effective amoun~ of the compound(s) of the invention or mixtures thereof, effective to alter the normal growth pattern of said plants.
The following disclosure also describes chemical intermediates and processes for preparing the compound of for-mula I.
The invention will be further described hereinbelow.
FURTHER DESCRIPTION OF THE INVENTION
AND THE PREFERRED EMBODIMENTS
.
The compound of Formula (I) can be conveniently pre-pared by the following schematically represented process:

~. $~

CH3CH2 \ ~0 ~ OEI
+ H2NOR - ~ I
(B) 1~ CE~[2cHscH2c~I3 (A) CH
wherein Rl is 3-trans-chloroallyl.
This process can be conveniently effected ky contac-ting Compound (A) with 3-trans-chloroallyloxyamine (B), prefer-ably in an inert organic solvent.
Typically, this process is conducted at temperatures in the range of about from 0 to 80C, preferably about from 20 to 40C, for about from 1 to 48 hours, preferably about from 4 to 12 hours, using about from 1 to 2, preferably 1.05 to 1.2 moles of 3-trans-chloroallyloxya~ine (B) per mole of Compound (A). Suitable inert organic solvents which can be used include, ~or example, lower alkanols, e.g., methanol, ethanol, ethers, e.g., ethyl ether; methylene chloride. Two-phase water and immiscible organic solvent (e~g., hexane), and the like, and compatible mixtures thereof can also be used.
Trans-chloroallyloxyamine is a known compound and can be prepared via known procedures, such as, for example, des cribed in U.S. Patent No. 4,440,566. Conveniently, a hydro-~chloride salt of trans-chloroallyloxyamine can be used by neut-ralizing the salt with an alkali metal alkoxide, in situ.
; The starting materials of Formula (A) can be prepared via the general procedure described in U.S. Patent

- 4,4~0 566.
The compatible salts of Formula (I) can be prepared by conventional procedures, for example, via the reaction of the compound of Formula I with a base, such as, for example, sodium hydroxide, potassium hydroxide and the like, having the desired cation. Additional variations in the salt cation can , also be effected via ion exchange with an ion exchanye resin having the desired cation.
General Process Conditions The reaction product can be recovered from its reaction product mixture by any suitable separation and purifi-cation procedure, such as, for example, chromatography.
Suitable separation and purification procedures are, Eor example, illustrated in the Examples set forth hereinbelow.
Generally, the reactions described above are conduc-ted as liquid phase reaction and hence pressure is generallynot significant except as it affects temperature (boiling point) where reactions are conducted at reflux. Therefore, -these reactions are generally conducted at pressures of about from 300 to 3,000 mm of mercury and conveniently are conducted at about atmospheric or ambient pressure.
It should also be appreciated that where typical or preferred process conditions (e.g., reaction temperatures, times, mole ratios of reactants, solvents, etc.) have been given, that other process conditions could also be used.
Optimum rea~tion conditions (e.g., temperature, reaction time, mol ratios, solvents, etc.) may vary with the particular reagents or organic solvents used but can be determined by routine optimization procedures.
Where optical isomer mixtures are obtained, the res-pective optical isomers can be obtained by conventional resolu-tion procedures. Geometric isomers can be separated by conven-tional separation procedures which depend upon dif~erences in physical properties between the geometric isomers.

- 6a -However, it is generally preferable to use the desired isomeric starting material in the reaction.
Definitions As used herein the following terms have the following meanings unless expressly stated to the contrary: -The term "compatible salts" refers to salts which do not significantly adversely alter the herbicidal properties of the parent compound. Suitable salts include cation salts such as, for example, the cation salts of lithium, sodium, potas-sium, alkali earth metals, copper, zinc, ammonia, quaternary ammonium salts, and the like.
The term "room temperature" or "ambient temperature"
refers to about 20-25C.
Utility The compositions containing the compound of Formula (I) and its salts exhibit both pre- and post-emergent herbici-dal activity and exhibit especially good herbicidal activity against grasses. The compositions exhibit especially good 2Q phytotoxicity against foxtail, Bermudagrass, crabgrass, rhi-zone, Johnsongrass and volunteer corn ~hich are weed species which are generally very difficult to control.
Generally, for post-emergent applications, the herb-icidal compositions are applied directly to the foliage or other plant parts. For pre-emergence applications, the herb-icidal compositions are applied to the growth medium, or pros-pective growth medium, for the plant. The op-timum amount of the herbicidal composition will vary with the particular plant species, and the extent of plant growth, if any, and the par-ticular part of the plant which is contacted and the extent ofcontact. The optimum dosage can also vary with the general ,,;
, '- . .

~ ~8~ ~ ~

- 6b -location, or environmen-t (e.g., sheltered areas such as green-houses compared to exposed areas such as fields~, and type and degree of control desired. Generally, for both pre- and post-emergent control, the present compositions are applied to pro-vide the compound of formula I at rates of about from 0.02 to 60 kg/ha, preferably about from 0~02 to 10 kg/ha.
Also, although in theory the compounds can be applied undiluted, in actual practice they are applied as a composition or formulation comprising an effective amount of the compound of formula I and an acceptable carrier. An acceptable or com-patible carrier (agriculturally acceptable carrier) is one which does not significantly adversely affect the desired bio-logical effect achieved by the active compounds, save to dilute it. Typically, the composition contains about from 0.05 to 95%
by weight of the compound of Formula (I) or mixtures thereofO
Concentrates can also he made having high concentrations designed for dilution prior to application. The carrier can be a solid, liquid, or aerosol. The actual compositions can take the form of granules, powders, 01 ~7~

dusts, solutions, emulsions, slurrie~s, aerosols, and the like.
05 Suitable so]id carriers which can be used include, for example, natural clays ~such as kaolin, atta-pulgite, montmorillonite, etc.), talcs, pyrophyllite, diatomaceous silica, synthetic fine silica, calcium alumi-nosilicate, tricalcium phosphate, and the like. Also, 10 organic materials, such as, for example, walnut shell flour, cotton-seed hulls~ wheat flou~, wood flour, wood bark flour, and the like can also be used as carriersO
Suitable liquid diluents which can be used include, for example, water, organic solvents (e~gO, hydrocarbons such 15 as benzene, toluene7 dimethylsulfoxide "~erosene, diesel fuel, fuel oil, petroleum naphtha, etc.), and the like.
Suitable aerosol carriers which can be used include con-ventional aerosol carriers such as halogenated alkanes, etc.
The composition can also contain various promo-ters and surface-active agents which enhance the rate of transport of the active compound into the plant tissue such as, for example, organic solvents, wetting agents and oils, and in the case of compositions designed for pre-~5 emergence application agents which reduce the leachability of the compound or otherwise enhance soil stability. Crop oils, such as, for example, soybean oils, paraffin oils and olefinic oils, are especially advantageous as carriers or additives in that they enhance phytotoxicity.
The composition can also contain various com-patible adjuvants`~ stabilizers, conditioners, insecti-cides, fungicides, and if desired, other herbicidally active compounds.
One convenient concentrate formulation which can be used comprises 23-27~ by weight of the active herbicide of the invention~ 2 to 4% by weight of an emulsifier, for example~ calcium alkylbenzene sulronates, octylphenol-ethoxylate, etc., or mixtures thereof, and about 70-75~
organic solvent, for example, xylene, etc. The concen--trate is mixed with water and preferably a crop oil prior 0l -8--to application and applied as a water emulsion containing about 0.5 to 2~ of a crop oil, for example, soybean oils, oS and paraffinic oils and olefinic oilsO Conveniently, the herbicide is applied as water emulsion containing about 0.02-0.6 wt. ~, preferably 0~O7-OD15 wt. % of the herbi-cide, of the invention; about 0.~01-0.01 wt. ~ of an emul-sifier, about 0.08-2~5 wt. % of an organic solvent and 10 about 95 to 99 wt. ~ water. Preferably, the composition also contains about 0.25 to 2 wt. % of a crop oil. The application composition can be conveniently prepared by mixing the concentrate formulation with about l/4 to 1/2 the desired amount of water. Then admixing the crop oil 15 and then adding the remaining amount of water. If no crop oil is used, then the water and concentrate formulation are simply admixed together.
A further understanding of the invention can be had in the following non-limiting Preparation(s) and Example(s). Wherein, unless expressly stated to the con-trary, all temperatures and temperature ranges refer to the Centigrade system and the term "ambient" or "room temperature" refers to about 20-25C~ The term "percent"
or "~" re~ers to weight percent and the term "mole" or "moles" refers to gram molesO The term "equivalent"
refers to a quantity of reagent equal in moles, to the moles of the preceding or succeeding reactant recited in that example in terms of finite moles or finite weight or volume. Where given, proton-magnetic resonance spectrum (p.m.r. or NMR) were determined at 60 mHz, signals are assigned as singlets (s), broad singlets (bs~, doublets (d), double doublets (dd), triplets (t), double triplets (dt), quartets (q), and multiplets (m); and cps refers to cycles per second. Also where necessary examples are repeated to provide additional starting material for sub-sequent examples~

~0 , ~L~;~5~$
~1 _9_ EXAMPLES
_xam~le l

5 Trans-2-[1-(3-chloroallyloxyamino) propylidene]-5-(2-ethylthiopropyl)-cyclohe~ane-l,3-dione In this example, 17.2 g (0.0636 mol) of 2-pro-pionyl-5-(2-ethylthiopropyl)cyclohexane-l,3~dione: 0.9 g (0.0153 mol) o ace~ic acid, and lO.9 g (0.0757 mol) of 10 3-trans-chloroallyloxyamine in 35 ml of water were added to 20 ml of hexane and stirred~ Aqueous 5 wt. % sodium hydroxide was slowly added over about 15 minutes until 3~0 g ~0.0757 m + small excess) of sodium hydroxide had been added - pH of reaction mixture about 6. The mixture was 15 heated to and maintained at 40C for 2-l/2 hours and then eooled to room temperature. The organie (i.e., hexane) phase was separated and washed with lO ml of aqueous 5 wt.
% hydrochloric aeid and then aqueous 6.25 wt. % sodium hydroxide added until pHl2. The aqueous phase was separated and admixed with 25 ml of hexane and the pH
adjusted to 5.4 by the dropwise addition of aqueous 36 wt. ~ hydroehlorie acid over an ice bath. The organie phase was separated, dried over magnesium sulfate and then coneentratec3 by evaporation affordin~ 18.0 g of a erude product. The crude product was purified by column ehromatography over silica gel eluting with hexane:methylene chloride affording the purified title compound as an oil. Elemental analysis carbon calculated 56.73%, found 56.63~; Hydrogen calculated 7.28~, found 0 7.55%; Nitrog~n 3.89%, found 3.S5%.
Example 2 Sodium 2 11~13-trans-ehloroallyloxyamino~
propylidene-3-oxo-5-(2-ethylthiopropyl)-_ __ cyelohex-l-en-l-olate This example illustrates a procedure whieh ean be used to prepare the title compound.
A solution containing O.Ol mole of sodium hydroxide dissolved in 2 ml of water is added to a solu-tion eontaining O.Ol mole of 2-[l-(3-trans-chloroallyl~
oxyamino) propylidene-5-(2-ethylthiopropyl)-eyclohexane, l,3-dione at room temperature. After the reaction is ; .
.

completed, the soLvents are evaporated off under vacuum affor-ding the l-hydroxy sodium salt of 2-[1-(3-trans-chloroallyl-oxyamino) propylidene-3-oxo-5-(2-ethylthiopropyl)-cyclohex-1-en-l-ol.
Example 3 In this e~ample, the compound of Formula 1, i.e., 2-[1-(3-trans-chloroallylo~yamino) propylidene~- 5-(2-ethyl~
thiopropyl~-cyclohexane-1,3-dione was tested, in composition form, using the procedures dascribed hereinbelow, for pre-emergent and post-emergent phytotoxic activity against a variety of grasses and broad-leaf plants including one grain crop and one broad-leaf crop.
Pre-Emergent Herbicide Test Pre-emergence herbicidal activity was determined in the following manner.
Test solutions of the respective compounds were pre--pared as follows:
355.5 mg of test compound was dissolved in 15 ml of acetone. 2 ml of acetone containing 110 mg of a nonionic sur-factant was added to the solution. 12 ml of this stock solu-tion was then added to 47.7 ml of water which contained the same nonionic surfactant at a concentration of 625 mg/l.
Seeds of the test vegetation were planted in a pot of soil and the test solotion was sprayed uniformly onto the soil surface to provide a dose of the compound of formula I oE 27.5 micrograms/cm2 unless otherwise specified in the following Tables. The pot was watered and placed in a greenhouse. The pot was watered intermittent:Ly and observed for seedling emer-gence, health of emerging seedlings, etc., for a 3-week period.

At the end of this period, the herbicidal effectiveness of the ~omposition was rated based on the physiological observations.
A O~to-100 scale was used, 0 representing no phytotoxicity, 100 representing complete kill. The results oE these tests are summarized in Table l.
Post-Emergent Herbicidal Test An aqueous formulation of the compound of formula I
was prepared in the same manner as described above for the pre-emergent test. This formulation was uniformly sprayed on 2 similar pots containing plants 2 to 3 inches tall (except wild oats, soybean and watergrass which were 3 to 4 inches tall~
(approximately 15 to 25 plants per pot) at a test compound dose of 27.5 microgram/cm2 unless otherwise specified in the following Tables. After the plants had dried, they were placed in a greenhouse and then watered intermittently at their bases as needed. The plants were observed periodically for phyto-toxic effects and physiological and morphological responses to the treatment. After 3 weeks, the herbicidal effectiveness of the compound was rated based on these observations. A 0-to-lO0 scale was used, 0 representing no phytotoxicity, lO0 represen-ting complete kill. The results of these tests are summarizedin Table 2.

9~;

o ~ o , .
u7 ~ ~n 3 C~ o u o .'~

~D ~
O tn o O s ,c) ~ s~

~ E ~

O

. . .

v~

. !
ul ~ :

o l ~
~ ~ O
O a~ D 3 r-l "
u~ v ~n .'.;
U h V ~ o N

V N 1~ ~ V ~ ~4 cl JJ
O O S~ ~
a~ ~ ~ .~v';

a~R O
o æl o O O In :

' ' ` : . ", Exa~p]e 3 In thi.s example, an aqueous formulation of the com-pound of formula I, ("1"~ was tested for pos~-emergence herbi-cidal activity at moderately low dosage rates side-by-side with its butylidene homolog, i.e., trans-2-~1-(3-chloroallyloxy-amino)butylidene]-5-(2- ethylthiopropyl)-cyclohexane-1,3-dione~
The tests were conducted in the same manner as des-cribed in Example 2, hereinabove, with the exception that the application rates specified in Table 3 were used and 4 repli-cate pots were used per test instead of 2. The average result of the four replicates are reported in Table 3 herein below, wherein 0 indicates no phytotoxicity and 100 indicates complete kill. Generally, phytotoxicities below about 20-30% are not considered significant because the plant can typically grow out of this a~ount of injury.

~; ~

~ s a~ 3 o X

~n ~ ~ ~" O ~
O X 1--l V CO O L~l o ,~
u~ O ~ O a~
~ ~ ' ~ O '~
G O O C~
S~ O O O O'~ ~ ~J ,C' 1,';' O~o m ~ cs ~ ~ ~ o .Q ~ E s (a~1cO~ O N

~ c) .~ Q r~
,~ n o o v SJ

c a) I $ o O o o a) ~ o o ~ t~ ~J ::~ '~3 S:~ ~

~ ~ ~ r~ ~ ~l O O
~) Ql U (~) ~1 o o o s , I
O ~1 'X 3 O ~
, r V $

o~o Q ~1 o o o c 0 ~ ~' b~
O ~ ,~
X ¦ ~ I C I C O
~ o ,~ o Z ~ J~ r~ ~ r~
~ 11 0 o 3 o ~, ~ ~, C) Z ~ C~
o ~, ~ o :

, .

Ol 16-As can be seen frorn Table 3, Compound 1 was substantially superior to comparison Compound C-l against 05 crabgrass, even at moderately low dosages. The superior-ity of Compound 1 will become more apparent at the low dosages used in Example 4 hereinbelow.
~xample 4 In this example, the title compound (I'l") was 10 tested for post-emergence herbicidal activity at very low dosage rate side by side with trans-2~ (3-chloroallyl-oxyamino)butylidene]-5-(2-ethylthiopropyl)-cyclohexane-1,3-dione ("C lll) and the commercial herbicide Sethoxdm ("C-2") (i.e., 2 [l~(ethoxyamino)butylidene3~5-(2-15 ethylthiopropyl)-cyclohexane-1,3-dione against an expanded list of weed grasses.
The tests were conducted in the same manner as described in Example 3, hereinabove, with the exception that the dosages indicated in Table 4 were used. The 20 re~ults of this testin~ are summarized in Table 4 wherein 0 indicates no phytotoxicity and lO0 indicates complete kill. Generally, phytotoxicities below about 20-30% are not considered meaningful because the plant can ~ypically grow out of this amount of injury.

~0 ~ ' , 2~
~ ".
coooo r ~oo ~;
~ ~ o o o o o o o o C~ o o o U) .,., o ~ `
V~ X U) ~, U~ .,, c~ O 3 ~ O ~5 1~ ~ ~
o~ ~ o o o oo o o o o o o o ~ ' ~ Z

v 3-al o~oO G~C~Oo ''"
~ U~ ~ X~
~ U~

~ u~ o r~ ~ o o ''~
~D a . 0 ~_I 1~ U) 1~

~ o 30 ~ Do o~o u~u~oo P~ 4~ X C ~ o o c~~o o o c~ o Cl~ O O
~ o ~

& d~ i ~ o ~ n o ~ ~D O O
~ 1~
C ~ .
a) # l ' ' C~ ~ ~ L~
U~ ~ N ~1 0 0 ~N 1--l 0 0 ~ r-i O O
~ ~ \ O O O O O O O O O O C p O O Or-~
U ~ Z; C~ V

:

~ ` .

', ~ , . . .

:~, ': ' : ' As can be seen from Table 4, with the exception of wild oats and yellow nutsedge, Compound 1 was superior 05 ko Comparison Compound C-l with respect to teach of the other weed species tested. Compounds 1 and C~l were about equivalent with respect to wild oats and both compounds were inactive at these dosage rates against yellow nut-sedge. Compounds 1 and C-l were both superior to Compound o C-2.
In terms of dosages required to evoke equivalent responses, an application rate of Compound 1 of 0.11 q/cm2 ~las about equivalent to an application rate of Compound C-l of 0.28 q/cm2 to control crabgrass and barnyardgrass.
15 An application rate of Compound 1 of 0.05 q/cm2 was about equivalent to an application rate of Compound C~l of 0.28 q/cm2 to control yellow foxtail and an application rate of Compound 1 of Ooll q/cm2 was superior to an application rate of Compound C-l of 0.28 q/cm2 to control Johnsongrass~
obviously, many modifications and variations of the invention described hereinabove and below can be made without departing from the essence and scope thereof.

i so

Claims (9)

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

1. A herbicidal composition, or a concentrate for preparing such a composition, comprising the compound 2[1-(3-trans-chloroallyloxyamino)propylidene]-5-(2-ethylthiopropyl)-cyclohexane-1,3-dione, of the formula I
(I) wherein R1 represents the 3-trans-chloroallyl group, or an agrochemically acceptable salt thereof, together with a compatible carrier.

2. A herbicidal composition according to claim 1 comprising a herbicidally effective amount of the compound of formula I together with a compatible carrier.

3. A composition according to claim 1 wherein the compatible carrier is a crop oil.

4. A method for controlling grassy plants which comprises applying a herbicidally effective amount of a composition according to claim 1 or 2, to the foliage or habitat of said plants.

5. A method for controlling grassy weeds in soybean crops which comprises applying a herbicidally effective amount of a composition according to claim 1 or 2 to the habitat of the soybean crops.

6. A method for controlling the grass species of foxtail, Bermudagrass, volunteer sorghum, broad-leaf signal-grass, goosegrass, red rice, sprangletop, Johnsongrass or volunteer corn which comprises applying a herbicidally effective amount of a composition according to claim 1 or 2 to said grass species or their habitat.

7. A herbicidal composition according to claim 1 comprising 0.02 - 0.6 wt. % of the compound of formula I; 0.001 - 0.15 wt. % of an emulsifier; 0.08 - 2.5 wt. % of an organic solvent and about 95 to 99 wt. % water.

8. The composition of claim 7 wherein said composition comprises about 0.25 - 2 wt. % of a crop oil.

9. A herbicidal concentrate composition according to claim 1 comprising 23 - 27 wt. % of the compound of formula I;
2 to 4 wt. % of an emulsifier and about 70 - 75 wt. % of an organic solvent.