Oxime esters of substituted quinoline-8-carboxylic acids and use thereof as herbicides

Abstract

Oxime esters of substituted quinoline-8-carboxylic acids of the formula ##STR1## where X is hydrogen, C.sub.1 -C.sub.4 -alkyl or halogen, Z is hydrogen or methyl, R.sup.1 is C.sub.1 -C.sub.6 -alkyl, C.sub.1 -C.sub.4 -alkoxymethyl, C.sub.1 -C.sub.4 -alkoxyethyl, C.sub.1 -C.sub.4 -alkylthiomethyl, C.sub.1 -C.sub.4 -alkylthioethyl, C.sub.1 -C.sub.4 -alkoxycarbonyl, C.sub.3 -C.sub.6 -alkenyl or C.sub.5 -C.sub.8 -cycloalkyl, each of which is unsubstituted or bears up to 3 methyl substituents, hydrogen, cyano, acetyl, benzoyl, unsubstituted benzyl or phenyl, or benzyl or phenyl bearing up to 3 substitutents selected from the group consisting of halogen, cyano, trifluoromethyl, C.sub.1 -C.sub.4 -haloalkyloxy, C.sub.1 -C.sub.6 -alkylthio, C.sub.1 -C.sub.4 -alkoxy, C.sub.1 -C.sub.4 -alkyl, hydroxy, dimethylamino or acetamino, R.sup.2 is hydrogen if R.sup.1 is not hydrogen, R.sup.2 further denotes C.sub.1 -C.sub.6 -alkyl, C.sub.1 -C.sub.4 -alkoxymethyl, chloromethyl, azolylmethyl, 1,1-dimethoxymethyl, cyano, C.sub.1 -C.sub.4 -alkoxycarbony, C.sub.1 -C.sub.4 -alkoxy, phenyl if R.sup.1 is H, CH.sub.3 or acetyl, or R.sup.2 denotes, when R.sup.1 is H or methyl, furyl, tetrahydrofuryl, thienyl, tetrahydropyranyl, tetrahydrothiopyranyl, dihydro-.DELTA..sup.3 -pyranyl or dihydro-.DELTA..sup.3 -thiopyranyl; further, R.sup.1 and R.sup.2, together with the carbon atom to which they are linked, denote C.sub.1 -C.sub.12 -cycloalkylidene, C.sub.5 -C.sub.6 -cycloalkenylidene or 4-oxacyclohexadienylidene, each of which is unsubstituted or bears up to 3 methyl substituents, it being possible, where the ring is 5-membered or 6-membered, or doubly unsaturated 6-membered, for it to contain an oxygen or sulfur atom, their preparation, and their use as herbicides.

Description

It is known from European Patent Application Nos. 60,429 and 104,389 that esters of herbicidal quinoline-8-carboxylic acid have herbicidal properties. However, the specific action of these esters is in every case hugely inferior to that of the free acid.

We have now found that oxime esters which are derived from quinoline-8-carboxylic acids and have the general formula I ##STR2## Where X is hydrogen, C.sub.1 -C.sub.4 -alkyl or halogen, Z is hydrogen or methyl, R.sup.1 is C.sub.1 -C.sub.6 -alkyl, C.sub.1 -C.sub.4 -alkoxymethyl, C.sub.1 -C.sub.4 -alkoxyethyl, C.sub.1 -C.sub.4 -alkylthiomethyl, C.sub.1 -C.sub.4 -alkylthioethyl, C.sub.1 -C.sub.4 -alkoxycarbonyl, C.sub.3 14 C.sub.6 -alkenyl or C.sub.5 -C.sub.8 -cycloalkyl, each of which is unsubstituted or bears up to 3 methyl substituents, hydrogen, cyano, acetyl, benzoyl, unsubstituted benzyl or phenyl, or benzyl or phenyl bearing up to 3 substituents selected from the group consisting of halogen, cyano, trifluoromethyl, C.sub.1 -C.sub.4 -haloalkyloxy, C.sub.1 -C.sub.6 -alkylthio, C.sub.1 -C.sub.4 -alkoxy, C.sub.1 -C.sub.4 -alkyl, hydroxy, dimethylamino or acetamino, R.sup.2 is hydrogen if R.sup.1 is not hydrogen, R.sup.2 further denotes C.sub.1 -C.sub.6 -alkyl, C.sub.1 -C.sub.4 -alkoxymethyl, chloromethyl, azolylmethyl, 1,1-dimethoxymethyl, cyano, C.sub.1 -C.sub.4 -alkoxycarbonyl, C.sub.1 -C.sub.4 -alkoxy, phenyl if R.sup.1 is H, CH.sub.3 or acetyl, or R.sup.2 denotes, when R.sup.1 is H or methyl, furyl, tetrahydrofuryl, thienyl, tetrahydropyranyl, tetrahydrothiopyranyl, dihydro-.DELTA..sup.3 -pyranyl or dihydro-.DELTA..sup.3 -thiopyranyl; further, R.sup.1 and R.sup.2, together with the carbon atom to which they are linked, denote C.sub.1 -C.sub.12 -cycloalkylidene, C.sub.5 -C.sub.6 -cycloalkenylidene or 4-oxacyclohexadienylidene, each of which is unsubstituted or bears up to 3 methyl substituents, it being possible, where the ring is 5-membered or 6-membered, or doubly unsaturated 6-membered, for it to contain an oxygen or suflur atom, have a more powerful herbicidal action than the quinoline esters hitherto disclosed. We have also found that the compounds of the formula I are more suitable than the parent quinoline carboxylic acids for the desired weed control at the postemergence stage, ie. through absorption of the active substances of the formula I via the plant leaves. In the light of the reduced action of all hitherto disclosed esters of quinolinecarboxylic acids, this property was not foreseeable and has to be regarded as surprising.

C.sub.1 -C.sub.6 -alkyl includes not only straight-chain but also branched paraffin hydrocarbons of 1 to 6 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert.-butyl, sec.-amyl, isoamyl, n-pentyl or n-hexyl.

C.sub.1 -C.sub.4 -alkoxymethyl is for example methoxymethyl, ethoxymethyl, isopropoxymethyl or n-butoxymethyl, while C.sub.1 -C.sub.4 -alkoxyethyl is for example 1-methoxyethyl, 2-methoxyethyl, 2ethoxyethyl and the like.

C.sub.1 -C.sub.4 -alkylthioethyl comprises 2-methylthioethyl, 1-methylthioethyl, 2-isopropylthioethyl, 2-isobutylthioethyl and the like.

Halogen can be fluorine, chlorine, bromine or iodine. Substituted phenyl is for example 4-fluorophenyl, 2-chlorophenyl, 3-chlorophenyl, 4-chlorophenyl, 4-bromophenyl, 4-cyanophenyl, 4-trifluoromethylphenyl, 4-methoxyphenyl, 3-methoxyphenyl, 2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 2-hydroxyphenyl, 4-dimethylaminophenyl, 4-acetaminophenyl, 3,4-dichlorophenyl, 2,4-dichlorophenyl, 2,6-dichlorophenyl, 3,5-dibromo-4-hydroxyphenyl or 3,5-diiodo-4-hydroxyphenyl.

C.sub.3 -C.sub.6 -alkenyl includes unsaturated straightchain or branched hydrocarbon radicals of up to 6 carbon atoms in the chain, eg. allyl, butenyl, isobutenyl, pentenyl, isopentenyl or hexenyl.

C.sub.5 -C.sub.8 -cycloalkyl includes for example cyclopentyl, cyclohexyl, 3,3,5-trimethylcyclohexyl, cycloheptyl or cyclooctyl.

Azolylmethyl is pyrazolylmethyl, imidazolylmethyl or triazolylmethyl.

When R.sup.1 and R.sup.2 are combined with the carbon atoms to which they are bonded to form a saturated or unsaturated ring which may be substituted by methyl and may contain an oxygen or sulfur in the ring, the oximes of the following ketones are covered: cyclobutanone, cyclopentanone, 3-methylcyclopentanone, 3-methylcyclopent-2-en-1-one, cyclohexanone, 2-methylcyclohexanone, 3-methylcyclohexanone, 4-methylcyclohexanone, 3,3,5-trimethylcyclohexanone, isophorone, cyclohex-2-en-1-one, cycloheptanone, cyclooctanone, cyclododecanone, tetrahydrothiopyran-4-one, 2,6-dimethyltetrahydrothiopyran-4-one, 2,6-dimethyltetrahydropyran-4-one, 2,6-dimethylpyran-4-one, tetrahydropyran-4-one, thiopyran-4-one, 2,6-dimethylthiopyran-4-one, tetrahydrofuran-3-one, benzoquinone, toluquinone, xyloquinone and the like.

The novel compounds of the formula I are obtained by reacting for example an acid chloride of the formula II (prepared from the known quinoline-8-carboxylic acids as described in EP No. 60,429) with an oxime R.sup.1 R.sup.2 C.dbd.N--OH at from -10.degree. C. to 120.degree. C., preferably from 10.degree. C. to 50.degree. C., in an inert solvent in the presence of a baase. Suitable solvents are pyridine, toluene, chlorobenzene, methylene chloride, methyl tert.-butyl ether, tetrahydrofuran and the like. As suitable bases pyridine, triethylamine, 1,8-diazabicyclo[5.4.0]undec-7-one (=DBU) or, in the prepatation by Schotten-Baumann, aqueous alkali metal hydroxide solution or alkali metal carbonate solution.

The R.sup.1 R.sup.2 C.dbd.NOH oximes used are known compounds or can be obtained in the customary manner which follows from the respective structural formula. Oximes of saturated (aliphatic) or olefinically unsaturated ketones or of olefinically unsaturated or aromatic aldehydes are preferred on account of the particularly smooth course of reaction.

The reaction product is worked up, if pyridine is used, by pouring into water, but if a water-immiscible solvent is used by extraction with water, washing with dilute mineral acid, deacidifying, drying and evaporating under reduced pressure. The synthesis of esters of benzaldoximes is generally only possible with the pyridine variant, since the products decompose when hot or in the presence of strong acids to benzonitriles and the known quinolinecarboxylic acids.

The oximes of the formula III are usually present in the form of a mixtures of their syn- and anti-isomers. For that reason the compounds of the formula I can likewise be obtained in the form of syn-/anti-isomer mixtures. No isomers appear if oximes of symmetrical ketones such as acetone, cyclopentanone, cyclohexanone etc. are used.

If the crude products need to be purified, this is easily done in the case of esters of ketoximes by recrystallizing from ethyl acetate or the like, while the oxime esters of benzaldehydes are epedientlly purified by reprecipitating from ethanol/water or by chromatography.

EXAMPLE 1

Acetone oxime esters of 3,7-dichloroquinoline-8-carboxylic acid

95 g (1.2 mol) of pyridine are added to a solution of 87.6 g (1.2 mol) of acetone oxime in 1.5 l of methylene chloride, followed by adding 260.5 g (1 mol) of 3,7-dichloroquinoline-8-carbonyl chloride a little at a time with ice cooling to maintain the temperature within the range from 15.degree. to 20.degree. C. After 8 hours of stirring at 25.degree. C. the reaction mixture is extracted twice with 200 ml of 5% strength HCl and washed once with water. The organic phase is then separated off and dried over MgSO.sub.4, and the methylene chloride is driven off under reduced pressure. The residue is recrystallized from ethyl acetate and dried under reduced pressure to leave 240 g (81%) of a white powder having a melting point of 131.degree.-132.degree. C.

EXAMPLE 2

Benzaldehyde oxime ester of 3,7-dichloroquinoline-8-carboxylic acid (compound No. 16 of Table I)

6.7 g (55 mmol) of benzaldehyde oxime are dissolved in 50 ml of pyridine, and 13 g (50 mol) of 3,7-dichloroquinoline-8-carbonyl chloride are added at 0.degree. C. a little at a time. After 3 hours of stirring the reaction mixture is poured into a mixture of 100 ml of ice-water and 50 ml of glacial acetic acid, and the precipitated solid is filtered off with suction, stirred up with 150 ml of NaHCO.sub.3 solution, is filtered off again with suction and washed with water. Drying under reduced pressure leaves 9 g of a pale brown solid (53% yield) having a melting point of 166.degree.-168.degree. C.

EXAMPLE 3

Cyclohexane oxime ester of 3,7-dichloroquinoline-8-carboxylic acid (compount No. 57 in Table II)

13 g (50 mol) of 3,7-dichloroquinoline-8-carbonyl chloride are added at 15.degree.-20.degree. C. a little at a time to an ice-cooled solution of 11.3 g (0.1 mol) of cyclohexanone oxime in 100 ml of pyridine. After 3 hours of stirring the pyridine is removed in a rotary evaporator, and the residue is dissolved in CH.sub.2 Cl.sub.2, washed with water, dried (MgSO.sub.4) and evaporated to dryness. The precipitated solid is recrystallized from diisopropyl ether and pentane (7:3).

Yield: 9.5 g (57%) of a white powder, melting point 142.degree.-143.degree. C.

By appropriately modifying the above examples it is possible to prepare the remaining compounds which are listed in Tables I and II and for the characterization of which the tables provide physical data. The compounds for which no physical data are shown can be obtained in a corresponding manner; owing to their structure as oxime esters of herbicidal quinolinecarboxylic acids, they can likewise be expected to have a powerful herbicidal action.

TABLE I__________________________________________________________________________ ##STR3##No. X R.sup.1 R.sup.2 m.p. (.degree.C.)__________________________________________________________________________ 1 CH.sub.3 CH.sub.3 CH.sub.3 111-112 2 Cl CH.sub.3 CH.sub.3 131-132 3 Cl C.sub.2 H.sub.5 CH.sub.3 130-132 5 Cl n-C.sub.3 H.sub.7 n-C.sub.3 H.sub.7 76-78 7 Cl i-C.sub.4 H.sub.9 i-C.sub.4 H.sub.9 92-94 8 Cl CH.sub.3 neopentyl 133-134 9 Cl CH.sub.3 4-methylpentyl 92-9410 Cl (CH.sub.2).sub.2CHC(CH.sub.3).sub.2 CH.sub.3 74-7511 Cl CH.sub.3 CH.sub.2OCH.sub.3 105-10712 Cl C.sub.2 H.sub.5 CH.sub.2 OCH.sub.3 86-8813 Cl CH.sub.3 CH(OCH.sub.3).sub.2 117-11814 Cl CH(CH.sub.3)S CH.sub.3 CH.sub.3 118-11915 Cl benzyl CH.sub.316 Cl H phenyl 166-16817 Cl CH.sub.3 phenyl 173-17418 Cl phenyl CH.sub.2 Cl19 Cl phenyl ##STR4## 185-18620 Cl acetyl CH.sub.3 114-11521 Cl acetyl phenyl 167-16922 Cl 4-N(CH.sub.3).sub.2phenyl H 165-16623 Cl 2-Clphenyl H 158-16024 Cl 3 -Clphenyl H 155-15825 Cl 4-Clphenyl H 175-17726 Cl 4-Fphenyl H 155-15727 Cl 4-CF.sub.3phenyl H 182-18328 Cl 4-CH.sub.3phenyl H 165-16729 Cl 4-CH.sub.3 Ophenyl H 147-14930 Cl 3-CH.sub.3phenyl H 121-12331 Cl 3-CH.sub.3 Ophenyl H 141-14332 Cl 3-F.sub.3 CHCF.sub.2 O)phenyl H 138-14033 Cl 4-H.sub.3 CCONHphenyl H 174-17634 Cl 4-CNphenyl H 178-18035 Cl 3,4-Cl.sub.2phenyl H36 Cl 2,4-Cl.sub.2phenyl H 162-16337 Cl 2,4-(n-C.sub.6 H.sub.13S).sub.2phenyl H --38 CH.sub.3 CH.sub.3 C.sub.2 H.sub.5 74-7639 CH.sub.3 CH.sub.3 i-C.sub.3 H.sub.7 97-9840 CH.sub.3 n-C.sub.3 H.sub.7 n-C.sub.3 H.sub.7 92-9341 CH.sub.3 i-C.sub.4 H.sub.9 i-C.sub.4 H.sub.9 70-7242 Cl 2-thienyl CH.sub.3 127-12943 CH.sub.3 3-thienyl CH.sub.3 137-13844 Cl 2-furyl H --45 Cl 2-furyl CH.sub.3 163-16446 Cl 5,6-dihydro-3-thiopyranyl-3 H 225-22847 Cl 5,6-dihydro-3-pyranyl-3 CH.sub.3 159-16148 Cl 2-furyl n-C.sub.3 H.sub.7 --49 Cl 2,3-dihydro-6-methyl-5-pyran-6-yl50 Cl 4-hydroxy-3,5-dibromophenyl H 203-20551 Cl 4-hydroxy-3-5,diiodophenyl H52 Cl CH.sub.3 OC.sub.2 H.sub.5 129-13053 Cl CN CO.sub.2 C.sub.2 H.sub.5 138-13954 Cl 3-thienyl CH.sub.3 160-16255 CH.sub.3 4-CF.sub.3phenyl H 135-13756 CH.sub.3 2-Clphenyl CH.sub.3 160-162__________________________________________________________________________ TABLE II______________________________________ ##STR5## No. X ##STR6## m.p. (.degree.C.)______________________________________57 Cl cyclopentylidene 128-13058 CH.sub.3 cyclopenytlidene 105-10759 Cl cyclohexylidene 142-14360 CH.sub.3 cyclohexylidene61 Cl 3,3,5-trimethylcyclohexylidene 144-14562 Cl ##STR7## 140-14363 Cl 3-methylcyclopentylidene 132-13364 Cl 3-methylcyclohexylidene 122-12565 Cl 3-methyl-cyclopent-2-enylidene 15066 Cl cyclohex-2-enylidene67 Cl cycloheptylidene 120-12268 Cl 2,6-dimethylpyranylidene-4 --69 Cl 2,6-dimethylthiopyranylidene-4 --70 Cl tetrahydrothiopyranylidene-4 167-16871 Cl tetrahydropyranylidene-4 153-15572 Cl cyclododecylidene 164-16673 Cl 2,3-benzocyclopentylidene-1 164-16574 CH.sub.3 2,3-benzocyclopentylidene-1 175-17675 Cl 2,3-benzocyclohexylidene-1 178-17976 CH.sub. 3 2,3-benzocyclohexylidene-1 180-18177 CH.sub.3 3,3,5-trimethylcyclohexylidene 123-12578 CH.sub.3 isophoronylidene 118-12079 CH.sub.3 3-methylcyclopent-2-enylidene80 CH.sub.3 cycloheptylidene 108-11081 CH.sub.3 2,6-dimethylpyranylidene-4 --82 CH.sub.3 tetrahydropyranylidene-4 134-13583 CH.sub.3 tetrahydrothiopyranylidene-4 172-173______________________________________

The following compounds of the formula I may be prepared in the same manner:

______________________________________No. X Z R.sup.1 R.sup.2______________________________________84 C.sub.2 H.sub.5 H CH.sub.3 CH.sub.385 i-C.sub.3 H.sub.7 H CH.sub.3 CH.sub.386 Br H CH.sub.3 CH.sub.387 C.sub.4 H.sub.9 H CH.sub.3 CH.sub.388 Cl CH.sub.3 CH.sub.3 CH.sub.389 H CH.sub.3 CH.sub.3 C.sub.2 H.sub.590 CH.sub.3 H CH.sub.2CH.sub.2SCH.sub.3 CH.sub.391 CH.sub.3 H CH(CH.sub.3)SCH.sub.3 CH.sub.392 CH.sub.3 H ##STR8## CH.sub.393 CH.sub.3 H 2-thienyl CH.sub.394 Cl H phenyl pyrazolylmethyl95 Cl H phenyl imidazolylmethyl96 CH.sub.3 H phenyl CH.sub.2Cl97 CH.sub.3 H CH.sub.3 CH(OCH.sub.3).sub.298 Cl H C.sub.2 H.sub.5 C.sub.2 H.sub.599 Cl H n-C.sub.4 H.sub.9 n-C.sub.4 H.sub.9100 Cl H iso-C.sub.5 H.sub.11 CH.sub.3101 Cl H allyl CH.sub.3102 Cl H CH.sub.2CH CHCH.sub.3 CH.sub.3103 Cl H cyclopentyl CH.sub.3104 Cl H cyclohexyl CH.sub.3105 Cl H cyclooctyl CH.sub.3106 Cl H 2,6-Cl.sub.2phenyl H107 Cl H 2,4,6-(CH.sub.3).sub.3phenyl H108 CH.sub.3 H phenyl H109 CH.sub.3 H 4-Clphenyl H______________________________________

Use examples

The action on broadleaved weeds was investigated, the following plants being employed:

Avena sativa, Galium aparine, Lamium amplexicaule, Triticum aestivum and Veronica spp.

On postemergence application of 3.0 kg/ha of the compound of Example 1, Galium aparine is well controlled. Oats, as an example of a crop plant, suffered no damage whatsoever (Table I).

On application of 0.5 kg/ha of an agent based on the compound of Example 2, wheat remained completely undamaged. The active ingredient exhibited selective herbicidal properties (Table II).

In view of the spectrum of weeds which can be combated, the tolerance of the novel compounds by crop plants or the desired influence on their growth, and in view of the numerous application methods, the novel compounds may be used in a large number of crops, for example:

______________________________________Botanical name Common name______________________________________Allium cepa onionsAnanas comosus pineapplesArachis hypogaea peanuts (groundnuts)Asparagus officinalis asparagusAvena sativa oatsBeta vulgaris spp. altissima sugarbeetsBeta vulgaris spp. rapa fodder beetsBeta vulgaris spp. esculenta table beets, red beetsBrassica napus var. napus rapeseedBrassica napus var. napobrassica swedesBrassica napus var. rapa turnipsBrassica rapa var. silvestrisCamellia sinensis tea plantsCarthamus tinctorius safflowerCarya illinoinensis pecan treesCitrus limon lemonsCitrus maxima grapefruitsCitrus reticulata mandarinsCitrus sinensis orange treesCoffea arabica (Coffea canephora, coffee plantsCoffea liberica)Cucumis melo melonsCucumis sativus cucumbersCynodon dactylon Bermudagrass in turf and lawnsElais guineensis oil palmsFragaria vesca strawberriesGlycine max soybeansGossypium hirsutum cotton(Gossypium arboreumGossypium herbaceumGossypium vitifolium)Helianthus annuus sunflowersHelianthus tuberosus Jerusalem artichokeHevea brasiliensis rubber plantsHordeum vulgare barleyHumulus lupulus hopsIpomoea batatas sweet potatoesJuglans regia walnut treesLactuca sativa lettuceLens culinaris lentilsLinum usitatissimum flaxLycopersicon lycopersicum tomatoesMalus spp. apple treesManihot esculenta cassavaMedicago sativa alfalfa (lucerne)Mentha piperita peppermintMusa spp. banana plantsNicothiana tabacum tobacco(N. rustica)Olea europaea olive treesOryza sativa ricePanicum miliaceum milletPhaseolus lunatus limabeansPhaseolus mungo mungbeansPhaseolus vulgaris snapbeans, green beans, dry beansPennisetum glaucum pearl milletPicea abies Norway spruceAbies alba fir treesPinus spp. pine treesPisum sativum English peasPrunus avium cherry treesPrunus domestica plum treesPrunus dulcis almond treesPrunus persica peach treesPyrus communis pear treesRibes sylvestre redcurrantsRibes uva-crispa gooseberriesRicinus communis castor-oil plantsSaccharum officinarum sugar caneSecale cereale ryeSesamum indicum sesameSolanum tuberosum Irish potatoesSorghum bicolor (s. vulgare) sorghumSorghum dochna sorgoSpinacia oleracea spinachTheobroma cacao cacao plantsTrifolium pratense red cloverTriticum aestivum wheat Vaccinium corymbosum blueberriesVaccinium vitis-idaea cranberriesVicia faba tick beansVigna sinensis (V. unguiculata) cow peasVitis vinifera grapesZea mays Indian corn, sweet corn, maize______________________________________ To increase the spectrum of action and to achieve synergistic effects, the novel quinolinecarboxylic acid derivatives may be mixed and applied together with numerous representatives of other herbicidal or growth-regulating active ingredient groups.

It may also be useful to apply the compounds of the formula I in admixture with other crop protection agents, e.g., agents for combating pests or phytopathogenic fungi or bacteria. The compounds may also be mixed with solutions of mineral salts used to remedy nutritional or trace element deficiencies. Non-phytotoxic oils and oil concentrates may also be added.

TABLE III__________________________________________________________________________Control of Echinochloa crus-galli in rice onpre- and postemergence application of novel compounds in the greenhouse ##STR9## Test plants and % damageEx. no. X R.sup.1 R.sup.2 kg/ha Type of application Oryza sativa Echinochloa crus-galli__________________________________________________________________________20 Cl acetyl methyl 0.25 preemergence 0 9521 Cl acetyl phenyl 0.5 " 10 9812 Cl ethyl methoxymethyl 0.5 " 0 95 5 Cl propyl propyl 0.5 postemergence 10 9020 Cl acetyl methyl 0.125 " 0 9012 Cl ethyl methoxymethyl 0.25 " 0 90 3 Cl ethyl methyl 0.5 " 10 95__________________________________________________________________________ To combat Echinochloa crus-galli, an important weed in rice, compounds nos. 20, 21 and 12 are suitable on preemergence application and compounds nos. 5, 20, 12 and 3 on postemergence application. Only slight damage, if any at all, is caused to the crop plant. TABLE IV__________________________________________________________________________Examples showing herbicidal action and tolerance by acrop plant on postemergence application in the greenhouse ##STR10## Test plants and % damageEx. no. X R.sup.1 R.sup.2 kg/ha Triticum aestivum Gallium aparine Veronica spp.__________________________________________________________________________13 Cl methyl CH(OH.sub.3).sub.2 0.25 10 90 9010 Cl (CH.sub.2 CHC(CH.sub.3).sub.2) methyl 0.5 0 90 9820 Cl acetyl methyl 0.5 0 95 9816 Cl H phenyl 0.5 0 90 98__________________________________________________________________________ For controlling broadleaved unwanted plants on postemergence application, active ingredients 13, 10, 20 and 16 are suitable. Wheat, as an example o a graminaceous crop, is only slightly damaged, if at all. The compounds are selective herbicidal active ingredients. TABLE V__________________________________________________________________________Control of wanted plant growth and tolerance by a crop; preemergenceapplication in the greenhouse ##STR11## Test plants and % damageEx. no. X R.sup.1 R.sup.2 kg/ha Triticum aestivum Echinochloa c. g. Gallium aparine Veronica spp.__________________________________________________________________________13 Cl methyl CH(OH.sub.3).sub.2 0.5 10 98 90 10020 Cl acetyl methyol 0.25 10 98 90 100__________________________________________________________________________ Compounds 13 and 20 are excellently tolerated by wheat, and offer good control of grassy and broadleaved unwanted plants.

Claims

1. An oxime ester of a substituted quinoline- 8-carboxylic acid of the formula ##STR12## where X is hydrogen, C.sub.1 -C.sub.4 -alkyl or halogen, Z is hydrogen or methyl, R.sup.1 is C.sub.1 -C.sub.6 -alkyl, C.sub.1 -C.sub.4 -alkoxymethyl, C.sub.1 -C.sub.4 -alkoxyethyl, C.sub.1 -C.sub.4 -alkylthiomethyl, C.sub.1 -C.sub.4 -alkylthioethyl, C.sub.1 -C.sub.4 -alkoxycarbonyl, C.sub.3 -C.sub.6 -alkenyl or C.sub.5 -C.sub.8 -cycloalkyl, each of which is unsubstituted or bears up to 3 methyl substituents, hydrogen, cyano, acetyl, benzoyl, unsubstituted benzyl or phenyl, or benzyl or phenyl bearing up to 3 substituents selected from the group consisting of halogen, cyano, trifluoromethyl, C.sub.1 -C.sub.4 -haloalkyloxy, C.sub.1 -C.sub.6 -alkylthio, C.sub.1 -C.sub.4 -alkoxy, C.sub.1 -C.sub.4 -alkyl, hydroxy, dimethylamino or acetamino, R.sup.2 is hydrogen if R.sup.1 is not hydrogen, R.sup.2 further denotes C.sub.1 -C.sub.6 -alkyl, C.sub.1 -C.sub.4 -alkoxymethyl, chloromethyl, azolylmethyl, 1,1-dimethoxymethyl, cyano, C.sub.1 -C.sub.4 -alkoxycarbonyl, C.sub.1 -C.sub.4 -alkoxy, phenyl if R.sup.1 is H, CH.sub.3 or acetyl, or R.sup.2 denotes, when R.sup.1 is H or methyl, furyl, tetrahydrofuryl, thienyl, tetrahydropyranyl, tetrahydrothiopyranyl, dihydro-.DELTA..sup.3 -pyranyl or dihydro-.DELTA..sup.3 -thiopyranyl; further, R.sup.1 and R.sup.2, together with the carbon atom to which they are linked, denote C.sub.1 -C.sub.12 -cycloalkylidene, C.sub.5 -C.sub.6 -cycloalkenylidene or 4-oxacyclohexadienylidene, each of which is unsubstituted or bears up to 3 methyl substituents, it being possible, where the ring is 5-membered or 6-membered, or doubly unsaturated 6-membered, for it to contain an oxygen or sulfur atom.

2. A herbicidal composition containing an effective amount of a compound of the formula I in claim 1, and an inert diluent.

3. An oxime ester of the formula I as defined in claim 2, wherein X is Cl and R.sup.1 and R.sup.2 are each CH.sub.3.

4. A method of eliminating undesirable plant growth which comprises: applying to the plants or to the soil in which the plants will grow a herbicidally effective amount of an oxime ester as defined in claim 1.

5. A method of eliminating undesirable plant growth which comprises: applying to the plants or to the soil in which the plants will grow a herbicidally effective amount of an oxime ester as defined in claim 3.

6. A herbicidal composition which comprises a carrier or diluent and a herbicidally effective amount of the oxime ester of claim 3.