CA1184192A

CA1184192A - Cyclohexane-1,3-dione derivatives and their use for controlling undesirable plant growth

Info

Publication number: CA1184192A
Application number: CA000407744A
Authority: CA
Inventors: Dieter Jahn; Rainer Becker; Norbert Goetz; Bruno Wuerzer
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 1981-07-22
Filing date: 1982-07-21
Publication date: 1985-03-19
Also published as: ZA825198B; HU191185B; JPH0313221B2; DE3261762D1; DE3128960A1; EP0070495B1; JPS5824543A; EP0070495A1; ATE11039T1

Abstract

ABSTRACT OF THE DISCLOSURE: Cyclohexane-1,3-dione derivatives of the formula

Description

Cyclohexane~1,3-dione derivatives and their use for controlling _ _undesirable_plant_~rowth _ _ _ The present invention relates to cyclohexane~l,3-dione derivatives, herbicides containing these compounds as active ingredients, and processes for controlling undesirable plant growth using these compounds.
It has been disclosed that 5-arylcyclohexane-1,3-dione derivatives may be used for the selective control of undesirable grasses in broad-leaved crops (German Published Application DAS 2,439,104). Furthermore, it has been disclosed that the active ingredient is tolerated by the gramineous crop wheat particularly when the phenyl ring is p-substituted (Proc. 4th International Congress of Pesticide Chemistry (IUPAC), 1978, page 235), the best results being achieved with the p-methyl radical, as in 2-(1-ethoxyaminopropylidene)-5-(4-methylphenyl)-cyclohexane-1,3-dione. Particularly noteworthy in the above publication is the finding that when the alkoxy-aminoalkylidene radical is alkoxyaminobutylidene instead of alkoxyaminopropylidene, the herbicidal ac~ivity and the toleration by crops are reduced. In the experiments with wheat as the crop, the active ingredients described are exclusively ethoxyaminopropylidene-containing 5-arylcyclohexane-1,3-dione derivatives, which do little damage to wheat.
We have found that cyclohexane-1,3-dione derivatives of the formula .., /.

1 ~ NH-oR4 R O-A ~ ~ C (I) ~ ~ R3 R O

where R is alkylene of 3 or 4 carbon atoms, or phenyl, benzyl,

2 phenylethyl or phenylpropyl, each of which is unsubstituted or substituted by halogen, alkyl, alkoxy, nitro, cyano or sulfonyl, ~ is alkylene or alkenylene, each of which is of not more than 3 carbon atoms and may b~ substituted by 1 or 2 alkyl radicals of 1 to 5 carbon atoms, cyclohexyl, alkenyl of 2 or 3 carbon atoms, ethynyl or phenyl, R is hydrogen, or alkoxycarbonyl where alkoxy is of 1 or 2 carbon atoms, R is alkyl of 1 to 4 carbon atoms~ and ~ is alkyl of 1 to 3 carbon atoms, alkenyl of 3 or 4 carbon atoms, propargyl, or haloalkenyl of 3 or 4 carbon atoms and 1 to 3 halogen atoms, and agriculturally acceptable salts of these compounds have a good herbicidal action against undesirable grasses, and are very well tolerated by cereals, especially wheat, and other crops.
Thus, in accordance with another aspect, the present invention provides a process for combating unwanted plant growth, wherein the plants and/or their location are treated with a herbicidally effective amount of a compound of the formula I as defined above or an agriculturally acceptable salt thereof.
The compounds of the formula I can occur in several tautomeric forms, all of which are claimed:
NH-OR~ ~ N-oR4 RlO A ~ ~ ~

~ N-oR4 1 ~ N~OR
~ ~ \ 3 R O-A - ~ R3 Rl may, for example, be allyl, benzyl, fluorobenzyl, chloro-benzyl, bromobenzyl, dichlorobenzyl, trichlorobenzyl, nitro-benzyl, cyanobenzyl, methoxybenzyl, methylbenzyl, ethylben~yl, tert.-butylbenzyl, dimethylbenzyl, phenyl, chlorophenyl, i-propylphenyl/ dichlorophenyl, methylphenyl, dimethylphenyl, methoxyphenyl, 2-phenylethyl or.2-phenyl-n-propyl.
A may be methylene, methylmethylene, ethylmethylene, propylmethylene, cyclohexylmethylene, methylethylmethylene, methylvinylmethylene, methylpropinylmethylene, propylmethylene, 4-methylbutylmethylene, phenylmethylene, ethylene, propylene, methylpropylene or l-methylpropen-l-yl-ene.
R2 may be hydrogen, methoxycarbonyl or ethoxycarbonyl.

R3 may be methyl, ethyl, n-propyl, i propyl, n-butyl, sec.-butyl, i-butyl or tert.-butyl.
R may, for example, be methyl, ethyl, n-propyl, i-propyl, n-butyl, sec.-butyl, i-butyl, tert.-butyl, allyl, propar~yl/ l-chloroprop-l-en-3-yl, 2-chlcroprop-1-en-3-yl r 1,2 dichloroprop-1-en-3-yl or 1,1,2 trichloroprop-l~en-3-yl.
For the purposes of the invention, salts of the compounds of the formula I are understood as meaning, for ~ . ~

'~ . ,.

~ 4 ~ O.Z. 0050/35289 example the alkali metal salts in particular the potass;um salts and sodium salts and manganese salts copper salts zinc salts ;ron salts and barium salts.
The compounds can be obta;ned by reacting a com-pound of the formula o // O
R10-A~C (IT) \ \ R3 with a hydroxylamine derivative of the formula R40NH4Y where R1 A R2 R3 and R4 have the above meanings and Y is an an;on~
The react;on is advantageously carr;ed out in -the ' heterogeneous phase ;n an inert solvent at from û to 80C
or at the boiling point of the m;xture in the presence of a base. Examples of su;table bases are carbonates bicar-bonates acetates alcoholates hydroxides and oxides of alkal; metals and alkaline earth metals in particular of sodium potass;um magnes;um and calcium. It ;s also poss;ble to employ an organic base such as pyridine or a tertiary amine.
A well-defined pH range particularly suitable for the reaction is from 2 to 7 in part;cular from 4.5 to 5.5 and tnis ;s advantageously obtained by the addition of an acetate for exanple an alkal; metal açetate ;n part;cular sodium acetate or potassium acetate or their m;xtures.
The alkali metal acetate is employed for examp~e in an arnount of from 0~5 to 2 moles based on the ammonium compound.
Examples oE suitable solvents are methanol, ethanol, isopropanol, benzene, tetrahydrofuran, chloroform, aceto-nitrile, dichloroethane, ethyl acetate, dioxane and dimethyl-sulfoxide~
The reaction is complete after a few hours, and the product may be isolated by concentrating the mixture, adding water, extracting the mixture with a non-polar solvent, and distilling off the solvent under reduced pressure.
In addition, the compounds of the formllla I may be obtained by reacting the compound of the formula II with a hydroxylamine of the formula R4-o-NH2, where R4 has the above meanings, in an inert solvent, at from 0C to the boiling point of the mixture, e.g. from 0C to 80C, preferably from 15 to 70C.
Examples of suitable solvents are methanol, ethanol, isopropanol, cyclohexanol, methylene chloride, toluene, tetra-hydrofuran, acetonitrile, dichloroethane and ethyl acetate.
If appxopriate r the obtained compounds of formula (I) as defined above may be converted into agriculturally acceptable salts thereof. The sodium salts or potassium salts of the cyclohexane-1,3-dione derivatives may, for example, be obtained by treating these compounds with sodium hydroxide or potassium hydroxide in aqueous solution ox in an organic solvent, e.g. methanol, etharol or acetone D A sodium alco-holate or potassium alcoholate may also be used as the ba~eO
Other metal salts, for example the manganese salts, copper salts, zinc salts, iron salts and barium salts, may be prepared by reacting the sodium salt with the appropriate metal chloride in aqueous solution.
Compounds of the formula II may be prepared rom cyclohexane 1,3-diones of the formula III by conventional f'~

methods (Tetrahedron Lett., ~9, 2491~i the compounds of the formula II~ can also occur in the tautomeric forms IIIa and IIIb:

RlO~ ~~ ~ R O-A

III IIIa IIIb It is also possible to prepare compounds of the formula II via the enol ester intermediate, which is obtained, possibly as an isomer mixture, in the conversion of a compound of the formule III, and rearranged in the presence of an imidazole or pyridine derivative (Japanese Patent 54/063,052).
The compounds of the formula III are obtained by conventional processes, as can be seen from the equation helow:

. ;~

7 ~ O. Z . 0050/35289 R -O-A- CHO

O / ~ ~
CH 3- C- CH 3/ \ CH2 ( COOH ) 2 base / \~yridine O ' R10-A-CH=CH-C-CH3 Rl-O-A-CH=CH-C-OH
- 'I ' .' CH2 ( COOCH3 ) 2 ¦ CH 3-OH

CH3-ONa R -O-A- CH = CH- COOCH3 ~3-C-C~l2-cOOOc~3/c}13_oNa ,~
.. .

., //
R~-O-A--Q

1 ) ~OH
2) HCl ~ ' O

R1-O-A~
~\0 - 8 - O.Z. 0050/35289 The Exampies ~hicl1 follo~ ;llustrate the prepara-t;on of the cyclohexane-1,3-dione der;vatives. In the Examples, parts by ~e;ght bear tne same relat;on to parts by volume as that of the k;logram to the liter.

10.5 parts ~y weight of 2-butyryl-5~(4'-chloro-benzyloxyethylidene)-cyclohexane-1,3-dione, 3.1 parts by we;ght of ethoxyammonium chloride and 2.7 parts by ~eight of anhydrous sod;~Jm acetate in 100 parts by volume of ethanol were st;rred for 12 hours at roo~n temperature.
The solvent waS distilled off under reduced pressure, the residue l~zs st;rred with 120 parts of water and 100 parts of methylene chloride, the organ;c phase was separated off, the a~ueous phase was extracted u;th 50 parts of methylene chlor;de~ and the combined organ;c phases were washed with ~ater, dried over sod;um sulfate and concen-trated under reduced pressure. The product obtained was 2-ethoxyaminobutyl;dene-5 (4'-chlorobenzyloxyethylidene) cyclohexane-1,3-d;one with the follow;ng formula:
O

CH3 ~ ~ NH-OC2H5 2 ~ \0 ~ n-C3H7 1ngred~ent No.1 n24: 1.5424 C21H28ClN04 (3q4) calculated: C 64.03 H 7.16 N 3.56 Cl 9.00 found: C 63.9 ~ 7.0 ~l 3~7 Cl 9.3 10.0 par-s by we;ght of 2-butyryl 5-(4'-me~hyl benxyloxyethylidene)~cyclohexane-1,3-dione and 2.0 parts by weight of ethoxyamine in 100 parts by volume of ethanol were stirred for 12 hours at room temperature. The solvent was distilled off under reduced pressure, the residue was stirred with 120 parts of water and 100 parts of methylene chloride, the organic phase was separated off, the aqueous phase was extracted with 50 parts of methylene chloride, and the combined organic phases were dried over sodium sulfate and concentrated under reduced pressure. 2-Ethoxyaminobutylidene-(4'-methyl-benzyloxyethylidene)-cyclohexane-1,3-dione was obtained as an oil (active ingredient No. 2).
n 2: 1.5343 C22H31NO4 (373) calculated: C 70.75 H.8.37 N 3.75 found: C 70.2 H 8.4 N 3.8 The compounds given below were obtained in a corresponding manner:

~ / NH-oR4 RlO-A~= C\R3 `r~

~ 10 ~ 0~ Z ~ 0050~35289 C.) a~
O ~ ~ O Cl:lO ~D N ~-1 ~ n nIn ,~
r~ n ~ n In o ~
L~ ~nIn n In ~ ~n ~In In Q~ . . . . . . . . ~.
~jN ~ ~ ~--O a. ~ ~ Q ~ ~
L: ~a ~a ~a ~a ~a ~,a ~a ~ Na ~a ~1 :
=
~;

r~
~ ..~n Y ~ Y
P;

~;~ ~ q X ~ ~ X

~C~ -C~

N N O
h ~ a) o R R
h O
1:~ ~) ~ N
~3 C) (:~ : ~ ~1 _ ~r o ~n ~ r a: a~ o ~ ~`
Ei o o.æ. 0050/35289 ,_ O
~-1t~1`0a~ ~ ~
._ O ~Ll~~:r ~ r` t o r`
t~t~~'tl ~ ~ tY~ o~ t'l , .. ,, , , ~ U7 ~1 t~tO~ ~CD tO ~ r~ ~
~ ,,a ~at~ ~ t~a ~ ~a tr,a t~a ~a ~, ~~~, ~ ~ ~, ~, r~ I
~ ~~ ~ ~.
1~~ ~, ~ ~ ~ ~ S: ~, r~~ r~ ~ ~ ~ ~ ~ ~
P~ 0 au 0 tV td 0 0 a) 0 1~ 1~
t~l tl~ a C~ C~
t 1:~ ~: ~

t.'~
P; ~: ~ m ~ m -u-t.~

t,~ t~ I
~ q m~
I I ~) ^
m e v - , ~ , V
^ C.) I _ 11 t~ t~ p:
o m cv ~ I
_, o ,~ ~
N N ~:
~ aJ
R R Q
O : O
h S

~-1 ~1 0 r1 0 ,~ ~1 N,C N ~ U S::
U
~ ~ ,4 o Q~ ~ ~I~ a~ O ~ O 1-- oo O O

12 - 0.Z. 0050/35289 ._ o~ o ~ ~
o o ~ ~ u u~ Ln ~r ~ ~ a ~ a ~ a ~ ~ ~ a ~a ~ a ~/ ~ ~ ~ ~1 ~: s ~ ~ ~ ~ .c ~I ~ ~ ~ ~

~ - U~ : Y
r~ I
~:
O ,~r ~ ~ ~ ) y ~-Q~
.
~; ,~ ~ ~ a ~i ~ ~ ~ I

o ~ ~ ~ ~ ~o ~ C~ ~ CO
o o s~

- 13 O.Z. 0050/35289 ,~ .
C~ ~ ~ O ~D ~ ~ Ln ~ ~r Cl~ ~ OD ~ 0~ ~ ~D O Cl~ ~r U~
. . . . .
~1 a 2~ F~ ~ a~ ~ ~ a m ~, ~ o Y ~ ~ ~, m~
~; ~

m'~ m ir;

m ~ m m m m m m m m~ Y
~o ~ ~ ~, ::~
~ ~ ~ o R ~ ~ Q, --' : X - ~ ~ = _ _ ~r ~ R

~ ~ o ~ ~ ~ ~ u) ~ r~ c~
O O
V ~

0 - 14 O.Z. 0050/35289 1~-NMR spectroscopic data, based on tetramethylsilane as internal standard, and given in ~values (ppm). Abbreviations for the signal structures:
s = singlet, d = doublet, t = triplet, q = quartet, m = multiplet (strongest signal).

OR ~ /
CH -CH ~ ~ C " " ~'

3 ¦ ~ \ ~ NH-O-CH -

4.30 (m) 4.15 (q) 41 4.1 (m) 4.05 (q) 42 4.23 (m) 4.51 (d) 43 4.18 (m) 4.48 (d) 44 4.08 (m) 4.04 (q) 4.1 (m~ 4.09 (q) 47 4.21 (m) 4.49 (d) 48 4.13 (m) 4.06 (q) 61 4.21 (m) 4.48 (d) 62 4.25 (m) 4.05 (q) 63 4.30 (m) 4.50 (d) 79 4.30 (m) 4.55 (d) 4.35 (~) 4.10 (q) The following compounds of the formula I ma~ be obtained analogously:

- 15 - O.Z. 0050~35289 .

~ ~ ~:
P~ ~

e w c ~ l l l ~;

m m ~ m m m m m m m m w m 1~
I m I
,) ~ O I
I - I I ~ u~
m m m N ,_1 ~/
Q) ~ N N
~ N Q N ~ ~ N
N
~ ~ ~ ~ ~ ~rq ,4 0 ~ ~ X ~C O
C: h: ~: ::~ : O O h ~1 ~1 I .C ~ 0 ~1 ~) ~1 ~ ~ ~ ~ ~
~1 .~ N
~ 3 y o ~ r-! N ~ ~ ~ Dr~ : ~ O u~
O O
V ~

- 16 - O.Z. 0050/35289 ,~ Y ~ ~ ~ ~ ~
~;

~`
P~

~ ::~ m m m m m m m m m m m m m I tq o ~ C.~
C~ 11 1 1 : :
V mr~
m c) c, ~, N N ~ ~ ~
a) 0: 0 0 ~1 ~ X -h h ~ o O O ~ O
P; ~ U C) ~
~ ~ ~ ~ ~ ~r o o C3 ~

- 1 7 - 0 . Z . 0050/3528~

i~O

~
~Y

_~ X

C.) I ~ - 3 3 ~
2 0 t~ ?t ~ ~ ~ ~

,1 ~ ,~ ~ ~ ,1 ,1 s s ~1 a~
o : ~:
Q. RJ 3 r o o ~ a 0 5~
~1 ~ IJ S l O
~ a) a~ aJ I ~ ~ I I I I
~ 0 0 ~r ~r Lt') ~

o ~ r Ln ~ o ~ ~ n ~o E3 ' ~ ~ ~ Lf11~ Lt~ L~) Ln n L~ D LD ~D
O Q

- lg - O.Z. 0050/35289 ,, Lf ,, m'` ~'` m~
C~ O X ~
I I ~ -r~
U
O = 5 ~I O
~; v m ~ m m m m m m m m m I ~ ~.
~ c) ~
I
1~
I ~ O
~ ~: ~ I I ~ ô

,. ..
N N
~ ~ a) a) ,-~ ,J - O O
>1 ~ S~ h O O ~1 ~; ~ ~ ~ ~ ~ ~
~3 - C) y ~: _ ~p r.
ra o Q~ c~ o ~ c~ o ~1 ~ 0 ~1 ~I
~ ~D 1~ r~ 1` Cl~ Cl~ COa~ co Cl:) : a~ o o o O O
C~ ~

- 19 - O.Z. 0050/35289 ~ pplication of the cyclohexane-1,3-dione derivatives of the formula I as herbicides may be effected for instance in the form of directly sprayable solutions, powders, suspensions, dlsper-sions, emulsions, oil dispersions, pastes, dusts, broadcasting agents, or granules by spraying, atomizing, dusting, broadcasting or watering. The forms of application depend~entirely o~ the pur-pose for which the agents are being used, but they must ensure as fine a distriblltion of the active ingredient as possible.
For the preparation of solutions, emulsions, pastes and oil dispersions to be ~prayed direct, mineral oil fractions of medium to high boiling point, such as kerosene or diesel oil, further coal-tar oils, and oils of vegetable or animal origin, aliphatic, cyclic and aromatic hydrocarbons such as benzene, toluene, xylene, paraffin, tetrahydronaphthalene, alkylated naphthalenes and their derivatives such as methanol, ethanol, propanol, butanol, chloro-form, carbon tetrachloride, cyclohexanol, cyclohexanone, chloro-benzene, isophorone, etc., and strongly polar solvents such as dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, water, etc. are suitable.
Aqueous formulations may be prepared from emulsion concen trates, pastes, oil dispersions or wettable powders by adding waterO To prepare emulsions, pastes and oil disperslons the ingre-dients as such or dissolved in an oil or solvent may be homoge-nized in water by means of wetting or dispersing agents, adherents or emulsifiers. Concentrates which are suitable for dilution with water may be prepared from active ingredient, wetting agent, ad-herent, emulsifying or dispersing agent and possibly 501vent or oil.

- 20 - O.Z. 0050/35289 The herbicides contain, in addition to inert additives, ~rom

5 to 95, and especially from 10 to 80, wt~ of cyclohexane--1,3-dione as active ingredient.
Examples of surfactants are: alkali metal, alkaline earth metal and ammonium salts of ligninsulfonic acid, naphthalenesul-fonic acids, phenolsulfonic acids, alkylaryl sulfonates, alkyl sulfates, and alkyl sulfonates, alkali metal and alkaline earth metal salts of dibutylnaphthalenesulfonic acid, lauryl ether sul-fate, fatty alcohol sulfates, alkali metal and alkaline earth metal salts oE fatty acids, salts of sulfated hexadecanols, hepta-decanols, and octadecanols, salts of sulfated fatty alcohol glycol ethers, condensation products of sulfonated naphthalene and naphthalene derivatives with formaldehyde, condensation prod~lcts of naphthalene or naphthalenesulfonic acids wlth phenol and form-aldehyde, polyoxyethylene octylphenol ethers, ethoxylated isooctyl-phenol, ethoxylated octylphenol and ethoxylated nonylphenol, alkyl-phenol polyglycol ethers, tributylphenyl polyglycol ethers, alkyl-aryl polyether alcohols, isotridecyl alcohol, fatty alcohol ethylene oxide condensates, ethoxylated castor oil, polyoxy-ethylene alkyl ethers, ethoxylated polyoxypropylene, laurylalcohol polyglycol ether acetal, sorbitol esters, lignin, sulfite waste liquors and methyl cellulose.
Powders, dusts and broadcasting agents may be prepared b~
mixing or grinding the active ingredients with a solid carrier.
Granules, e.g., coated, impregnated or homogeneous granules, may be prepared by bonding the active ingredients to solid car-riers. Examples of solid carriers are mineral earths such as silicic acid, silica gels, silicates, talc, kaolin, Attaclay, - 21 - O.Z. 0050/35289 limestone, lime, chalk, bole, loess, clay, dolomite, diatomaceous earth, calcium sulfate, magnesium sulfate, magnesium oxide, ground plastics, fertilizers such as ammonium sulfate, ammonium phosphate, ammonium nitrate, and ureas, and vegetable products such as grain flours~ bark meal, wood meal, and nutshell meal, cellulosic powders, etc.
EXAMPLE a 90 parts by weight of compound 1 is mixed with 10 parts by weight of N-methyl~alpha-pyrrolidone. A mixture is obtained which is suitable for application in the form of very fine drops.
EXAMPLE b 10 parts by weight of compound 1 is dissolved in a mixture consisting of 90 parts by weight of xylene, 6 parts by we ght of the adduct of 8 to 10 moles of ethylene oxide and 1 mole of oleic acid~N-monoethanolamide, 2 parts by weight of the calcium salt of dodecylbenzenesulfonic acid, and 2 parts by weight of the adduct of 40 moles of ethylene oxide and 1 mole of castor oil.
EXAMPhE c 20 parts by weight of compound 44 is dissolved in a mixture consisting of 60 parts by weight of cyclohexanone, 30 parts by weight of isobutanol, 5 parts by weight of the adduct of 7 moles of ethylene oxide and 1 mole of isooctylphenol, and 5 parts by weight of the adduct of 40 moles of ethylene oxide and 1 mole of castor oil.
EXA~PLE d 20 parts by weight of compound 1 is dissolved ln a mixture consisting of 2S parts by weight of cyclohexanol, 65 parts by weight of a mineral oil fraction having a boiling point between - 22 - O.Z. 0050/35289 210 and 280C, and 10 parts by weight of the adduct of 40 moles of ethylene oxide and 1 mole of castor oil.
EXAMPLE e 820 parts by weight of compound 1 is well mixed with 3 parts by weight of the sodium salt of diisobutylnaphthalene-alpha 5ul-fonic acid, 10 parts by weight of the sodium salt of a lignin-sul-fonic acid obtained from a sulfite waste liquor, and 7 parts by weight of powdered silica gel~ and triturated in a hammer mill.
EXAMPLE f 5 parts by weight of compound 44 is intimately mixed with 95 paxts by weight of particulate kaolin. A dust is obtained con-taining 5% by weight of the active ingredient.
~XAMPLE g 30 parts by weight of compound 1 is intimately mixed with a mixture consisting of 92 parts by weight of powdered silica gel and 8 parts by weight of paraffin oil which has been sprayed onto the surface of this silica gel. A formulation of the active ingre-dient is obtained having good adherence.
EXAMPLE h 40 parts by weight of compound 44 is intimately mixed with 10 parts of the sodium salt of phenolsulfonic acid-urea-form-aldehyde condensater 2 parts of silica gel and 48 parts of water to give a stable aqueous dispersionO Dilution in 100,000 parts by weight of water gives an aqueous dispersion containing 0.0~ wt% of active ingredient.
EXAMPLE i 20 parts of compound 1 i3 intimately mixed with 12 parts of the calcium salt of dodecylbenzenesulfonic acid, 8 parts of a ,, .

- 23 - O.Z. 0050/35289 fatty alcohol polyglycol ether, 2 parts of the sodium salt of a phenolsulfonic acid-urea-formaldehyde condensate and 68 parts of a paraffinic mineral oil. A stable oily dispersion is obtained.
The agents may be appliPd pre- or postemergence; the latter method is preferred.
The amount of active ingredient which is applied depends on the objective to be attained, the growth stage and type of plant, and on the weather conditions, and varies from 0.1 to 15 kg/ha and more, but is preferably from 0.25 to 1.5 kg/ha.
The influence of the cyclohexane-1,3-dione derivatives of the formula I on the growth of unwanted and crop plants was demonstrated in greenhouse experiments.
The vessels employed were plastic flow0rpots having a volume of 300 cm3 and containing, as substrate, a sandy loam with about 1.5~ humus. The seeds of the test plants were sown shallow, and separately, according to species. For the postemergence treatment described here, the plants were first grown to a height of 5 to 15 cm, depending on growth form. The application rates varied from active ingredient to active ingredient, and were either 0.25, 0.5 at 1.0 kg/ha.
The active ingredients were sprayed as an aqueous suspension or emulsion by means of finely distributing nozzles.
The prior art compound -C ~ -0-C2~5 (A) - 24 - O.Z. 0050/35289 disclosed as having a particularly selective and good herbicidal action in German Published Application DAS 2,439,104 was used for comparison purposes.
The experiments were run for from 2 to 4 weeks. During this period, the plants were tended and their reactions to the various treatments assessed. The scale used for assessment was O to lOO, O
denoting no damage or normal emergence, and 100 denoting nonemer-gence or complete destruction of at least the visible plant parts.
The test plants were Alopecurus myosuroides, Avena fatua, Beta vulgaris, Lolium multiflorum, Triticum aestivum, Glycine max., Echinochloa crus-galli, Setaria italica, Sorghum bicolor, Rottboellia exaltata, and ~ordeum vulgare.
The results revealed that compound no. 44, applied post-emergence at a rate of 0.25 kg/ha, had an action on the unwanted grasses Alopecurus myosuroides and Avena fatua which was somewhat weaker than that of comparative compound A. At a rate of loO kg/ha, the herbicidal action of both compounds on both weeds is identical. ~owever, the tolerance of compound no. 44 by wheat is clearly better than the tolerance of comparative compound A.

The experiments also showed that compound no. l, on post-emergence application of 0.25 kg/ha, is superior to comparative compound A (applied at the same rate) in combating the grass species Alopecurus myosuroides and Lolium multiflorum. This com-pound too is much better tolerated by wheat than comparative compound A.
On postemergence application of l.O kg of compounds nos. 2, 8, 45, 72 and 73, these compound~ had an excellent action on unwanted grass species. Soybeans, as an example of a broadleaved crop plant, were not damaged.

- 25 - O.Z. 0050/35289 Compounds nos. 27, 28 and 50, applied postemergence at 0.5 kg/ha, selectively controlled unwanted grasses in cereals, such as barley and wheat, and in soybeans.
The compounds of the formula I have a selective herbicidal action not only in cereal species (preferably wheat), but also in broadleaved crops, such as sugarbeets, soybeans, cotton, rape, and sunflowers, and in oiher crops not belonging to the Gramineae family.
If certain crop plants tolerate the active ingxedients less well, application techniques may be used in which the herbicidal agents are sprayed from suitable equipment in such a manner that the leaves of sensitive crop plants are if possible not touched, and the agents reach the soil or the unwanted plants growing beneath the crop plants (post directed, lay-by treatment).
To increase the spectrum of action and to achieve synergistic effects, the cyclohexane 1,3-dione derivatives of the formula I
may be mixed and applied together with prior art cyclohexane--1,3-dione derivatives and with numerous representatives of other herbicidal or growth-regulating active ingredient groups. Examples of suitable mixture components are diazines, 4H-3,1-benzoxazine derivatives, benzothiadiazinones, 2,6-dinitroanilines, N-phenyl carbamates, thiolcarbamates, halocarboxylic acids, triazines, amides, ureas, diphenyl ethers, triazinones, uracils, benzofuran derivatives, etc.
It may also be useful to apply the novel compounds, either alone or in combination with other herbicides, in admixture with other crop protection agents, e.g., agents for combating pests or phytopathogenic fungi or bacteria. The compounds may also be mixed - 26 - O.Z. 0050/35289 with solutions of min~ral salts used to remedy nutritional or trace element deficiencies. Wetting agents, spreader-stickers, non-phytotoxic oils and oil concentrates may be also be added to initiate the herbicidal action.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed, are defined as follows:

1. A cyclohexane-1,3-dione derivative of the formula (I) where R1 is alkylene of 3 or 4 carbon atoms, or phenyl, benzyl, 2-phenylethyl or phenylpropyl, each of which is unsubstituted or substituted by halogen, alkyl, alkoxy, nitro, cyano or sulfonyl, A is alkylene or alkenylene, each of which is of not more than 3 carbon atoms and may be substituted by 1 or 2 alkyl radicals of 1 to 5 carbon atoms, cyclohexyl, alkenyl of 2 or 3 carbon atoms, ethynyl or phenyl, R2 is hydrogen, or alkoxycarbonyl where alkoxy is of 1 or 2 carbon atoms;
R3 is alkyl of 1 to 4 carbon atoms, and R is alkyl of 1 to 3 carbon atoms, alkenyl of 3 or 4 carbon atoms, propargyl, or haloalkenyl of 3 or 4 carbon atoms and 1 to 3 halogen atoms, and agriculturally acceptable salts thereof.

2. 2-Ethoxyaminobutylidene-5-(4'-chlorobenzyl-oxyethylidene)-cyclohexane-1,3-dione.

3. 2-Ethoxyaminobutylidene-5-(4'-methyl-phenoxyethylidene)-cyclohexane-1,3-dione.

4. A process for the manufacture of a compound of the formula (I) as defined in claim 1, and agriculturally acceptable salts thereof, characterized in that a compound of the formula (II) (II) where R1, A, R2 and R3 have the meanings given in claim 1, is reacted with an ammonium compound of the formula R4ONH4Y, where R4 has the meanings given in claim 1 and Y is an anion, in an inert solvent, at from 0° to 80°C, and in the presence of a base, and, if appropriate, converting an obtained compound of formula (I) as defined above into an agriculturally acceptable salt thereof.

5. A process as defined in claim 4, wherein the base is an alkali metal acetate.

6. A process for the manufacture of a compound of the formula (I) as defined in claim 1 and agriculturally acceptable salts thereof, characterized in that a compound of the formula (II) (II) where R1, A, R2 and R3 have the meanings given in claim 1, is reacted with an hydroxylamine of the formula R4O-NH2, where R4 has the meanings given in claim 1, in an inert solvent, at from 0 to 80°C, and in the presence of a base, and, if appro-priate, the obtained compound of formula (I) as defined above is converted into an agriculturally acceptable salt thereof.

7. A process for the manufacture of a compound of the formula (I) as defined in claim 1 and agriculturally acceptable salts thereof, characterized in that a compound of the formula (II) (II) where R1, A, R2 and R3 have the meanings given in claim 1, is reacted either (i) with an ammonium compound of the formula R4ONH4Y, where R4 has the meanings given in claim 1 and Y is an anion, or (ii) with an hydroxylamine of the formula R4O-NH2, where R4 has the meanings given in claim 1, in an inert solvent, at from 0° to 80°C, and in the presence of a base, and, if appropriate, the obtained compound of formula (I) as defined above is converted into an agriculturally acceptable salt.

8. A process for combating unwanted plant growth, wherein the plants and/or their location are treated with a herbicidally effective amount of a compound of the formula (I) as defined in claim 1 or an agriculturally acceptable salt thereof.