N-phenyltetrahydrophthalimides

Abstract

N-Phenyltetrahydrophtalimides of the general formula I ##STR1## where R.sup.1 is hydrogen or halogen, R.sup.2 is halogen, R.sup.3 is hydrogen or C.sub.1 -C.sub.4 -alkyl, R.sup.4 is unsubstituted or C.sub.1 -C.sub.3 -alkoxy-substituted C.sub.1 -C.sub.8 -alkyl, C.sub.3 -C.sub.4 -alkenyl or C.sub.3 -C.sub.4 -alkynyl, and R.sup.5 is hydrogen or C.sub.1 -C.sub.4 - alkyl, methods for their manufacture, and their use as herbicides.

Description

N-Aryl-substituted tetrahydrophthalimides which have a herbicidal action are known. For example, EP-A-207,894 describes tetrahydrophthalimides of of the formula I' ##STR2## where the radicals have for example the following meanings:

R.sup.a and R.sup.b are identical or different and each is hydrogen or halogen;

R.sup.c and R.sup.d together denote, inter alia, a substituted or unsubstituted C.sub.2 -C.sub.3 -alkylene bridge; and

R.sup.e is, inter alia, hydrogen, cyano or C.sub.1 -C.sub.4 -alkyl.

However, the action of these compounds is unsatisfactory at low application rates.

The object of the invention was therefore to provide N-phenyltetrahydrophthalimide compounds which have, at low application rates, a better action on unwanted plants without damaging crop plants.

We have now found that tetrahydrophthalimides of the formula I ##STR3## where R.sup.1 is hydrogen or halogen, R.sup.2 is halogen, R.sup.3 is hydrogen or C.sub.1 -C.sub.4 -alkyl, R.sup.4 is unsubstituted or C.sub.1 -C.sub.3 -alkoxy-substituted C.sub.1 -C.sub.8 -alkyl, C.sub.3 -C.sub.4 -alkenyl or C.sub.3 -C.sub.4 -alkynyl, and R.sup.5 is hydrogen or C.sub.1 -C.sub.4 -alkyl, have an advantageous herbicidal action particularly when applied postemergence, and are selective in a number of crop plants.

By halogen, we mean fluorine, chlorine and bromine, halogen for R.sup.1 preferably being fluorine and for R.sup.2 preferably chlorine.

The term alkyl embraces straight-chain and branched radicals, e.g., methyl, ethyl, n-propyl and isopropyl.

The alkenyl and alkynyl radicals may also be straight-chain or branched. Examples of alkenyl radicals in formula I are 2-propenyl, 2-butenyl, 3-butenyl, and 2-isobutenyl, especially 2-propenyl and 2-butenyl; alkynyl radicals are usually propargyl, 2-butynyl and 3-butynyl.

The invention embraces the enantiomers, the diastereomers and mixtures thereof.

The N-substituted tetrahydrophthalimides are obtainable from 3,4,5,6-tetrahydrophthalic anhydride and an aniline of the formula V, e.g., in a solvent at a temperature of from 20.degree. to 200.degree. C., preferably 40.degree. to 150.degree. C. Suitable solvents are for example lower alkanoic acids such as glacial acetic acid or propionic acid, or aprotic solvents such as toluene or xylene in the presence of acidic catalysts such as aromatic sulfonic acids.

Preferred compounds I are those in which R.sup.1 is hydrogen or fluorine, R.sup.2 is chlorine, R.sup.3 is C.sub.1 -C.sub.2 -alkyl, R.sup.4 is C.sub.1 -C.sub.4 -alkyl, C.sub.3 -C.sub.4 -alkenyl or C.sub.3 -C.sub.4 -alkynyl and R.sup.5 is hydrogen or methyl.

The anilines of the formula V are obtained for example by reducing a nitrobenzene IV having the appropriate acetal structure by means of reducing agents such as iron or tin(II) salts. ##STR4##

The reduction can also be carried out as a catalytic hydrogenation with a noble metal catalyst such as platinum or palladium, or with Raney nickel under relatively mild conditions.

Nitroacetals IV are accessible by reaction of an appropriate benzaldehyde II in an inert solvent in the presence of an acid with a diol of the formula III: ##STR5##

The recommendations given in the examples below were employed to obtain further compounds of the general formula I using different starting compounds. These compounds and their physical data are given in the following table. Compounds without any physical data may be obtained from the corresponding materials in analogous manner. Because of their close structural similarity to the manufactured and investigated compounds they are expected to have a similar action.

EXAMPLE ##STR6##

(a) 19.4 g of n-butyl 2,3-dihydroxyisobutyrate is added to 18.6 g of 2-chloro-5-nitrobenzaldehyde and 0.5 g of p-toluenesulfonic acid in 250 ml of toluene, and the mixture is refluxed for 5 hours using a water separator. The mixture is cooled, the solvent is removed and the remainder is dried in a high vacuum. There is obtained 35 g of 3-(5-methyl-5-n-butyloxycarbonyl-1,3-dioxolan-2-yl)-4-chloronitrobenzene (oil).

(b) While refluxing, 34.4 g of the above nitro compound in 20 ml of methanol is added to a mixture of 16.8 g of iron powder in 30 ml of methanol and 75 ml of glacial acetic acid. The mixture is refluxed for 2 hours. After cooling, 250 ml of water is added and the mixture is subjected to suction filtration. The filtrate is extracted three times, each time with 100 ml of ethyl acetate, dried, concentrated and dried in a high vacuum. There is obtained 31 g of 3-(5-methyl-5-n-butyloxycarbonyl-1,3-dioxolan-2-yl)-4-chloroaniline (oil).

(c) 15.7 g of the above aniline and 7.6 g of cyclohexene-1,2-dicarboxylic anhydride are refluxed for 5 hours in 150 ml of glacial acetic acid. After cooling, 150 ml of water is added, followed by extraction twice with 100 ml of methylene chloride, drying and removal of the solvent. The product is purified by chromatography and dried in a high vacuum. There is obtained 9.0 g of N-[3-(5-methyl-5-n-butyloxycarbonyl-1,3-dioxolan-2-yl)-4-chlorophenyl]-3.4.5.6-tetrahydrophthalimide (oil) (Table 1, no. 1.027).

Table 1 contains further examples of active ingredients which can be prepared by this synthesis principle.

TABLE 1__________________________________________________________________________ ##STR7##No. R.sup.1 R.sup.3 R.sup.4 mp [.degree.C.] IR [cm.sup.-1 ]__________________________________________________________________________1.001 H H CH.sub.31.002 F H CH.sub.31.003 H CH.sub.3 CH.sub.3 oil 1715, 1481, 1377, 10881.004 F CH.sub.3 CH.sub.31.005 H CH.sub.2 CH.sub.3 CH.sub.3 oil 2938, 1715, 1481, 1378, 10881.006 F CH.sub.2 CH.sub.3 CH.sub.31.007 H H CH.sub.2 CH.sub.31.008 F H CH.sub.2 CH.sub.31.009 H CH.sub.3 CH.sub.2 CH.sub.3 oil 1715, 1480, 1376, 10881.010 F CH.sub.3 CH.sub.2 CH.sub.3 oil 1720, 1500, 1422, 10821.011 H CH.sub. 2 CH.sub.3 CH.sub.2 CH.sub.3 oil 2938, 1715, 1480, 1377, 10891.012 F CH.sub.2 CH.sub.3 CH.sub.2 CH.sub.3 oil 1721, 1500, 1422, 10831.013 H H (CH.sub.2).sub.2 CH.sub.31.014 F H (CH.sub.2).sub.2 CH.sub.31.015 H CH.sub.3 (CH.sub.2).sub.2 CH.sub.3 oil 2929, 1716, 1479, 1377, 10891.016 F CH.sub.3 (CH.sub.2).sub.2 CH.sub.3 oil 1720, 1500, 1422, 10821.017 H CH.sub.2 CH.sub.3 (CH.sub.2).sub.2 CH.sub.3 oil 2938, 1716, 1481, 1378, 10891.018 F CH.sub.2 CH.sub.3 (CH.sub.2).sub.2 CH.sub.3 oil 1721, 1500, 1422, 10831.019 H H CH(CH.sub.3).sub.21.020 F H CH(CH.sub.3).sub.21.021 H CH.sub.3 CH(CH.sub.3).sub.21.022 F CH.sub.3 CH(CH.sub.3).sub.21.023 H CH.sub.2 CH.sub.3 CH(CH.sub.3).sub.21.024 F CH.sub.2 CH.sub.3 CH(CH.sub.3).sub.21.025 H H (CH.sub.2).sub.3 CH.sub.31.026 F H (CH.sub.2).sub.3 CH.sub.31.027 H CH.sub.3 (CH.sub.2).sub.3 CH.sub.3 oil 2958, 1716, 1481, 1377, 10881.028 F CH.sub.3 (CH.sub.2).sub.3 CH.sub.3 oil 2958, 1721, 1500, 1423, 10821.029 H CH.sub.2 CH.sub.3 (CH.sub.2).sub.3 CH.sub.3 oil 2960, 1716, 1480, 1378, 10891.030 F CH.sub.2 CH.sub.3 (CH.sub.2).sub.3 CH.sub.3 oil 2960, 1721, 1500, 14221.031 H CH.sub.3 CH.sub.2 CH(CH.sub.3).sub.2 oil 2960, 1718, 1481, 1378, 10881.032 F CH.sub.3 CH.sub.2 CH(CH.sub.3).sub.21.033 H CH.sub.2 CH.sub.3 CH.sub.2 CH(CH.sub.2 CH.sub.3)(CH.sub.2).sub.3 CH.sub.3 oil 2932, 1717, 1481, 1378, 10891.034 F CH.sub.2 CH.sub.3 CH.sub.2 CH(CH.sub.2 CH.sub.3)(CH.sub.2).sub.3 CH.sub.3__________________________________________________________________________ TABLE 2______________________________________ ##STR8##No. R.sup.1 R.sup.3 R.sup.4 mp [.degree.C.] IR [cm.sup.-1 ]______________________________________2.001 H CH.sub.3 CH.sub.32.002 F CH.sub.3 CH.sub.32.003 H CH.sub.3 CH.sub.2 CH.sub.32.004 F CH.sub.3 CH.sub.2 CH.sub.32.005 H CH.sub.3 (CH.sub.2).sub.2 CH.sub.32.006 F CH.sub.3 (CH.sub.2).sub.2 CH.sub.32.007 H H CH(CH.sub.3).sub.2 oil 2936, 1717, 1418, 1376 11012.008 F H CH(CH.sub.3).sub.22.009 H H (CH.sub.2).sub.3 CH.sub.3 oil 2958, 1715, 1480, 1378 11002.010 F H (CH.sub.2).sub.3 CH.sub.32.011 H H CH.sub.3 oil 1715, 1481, 1378, 11042.012 F H CH.sub.32.013 H H (CH.sub.2).sub.2 CH.sub.32.014 F H (CH.sub.2).sub.2 CH.sub.3______________________________________ TABLE 3______________________________________ ##STR9##No. R.sup.3 R.sup.4 R.sup.5 mp [.degree.C.] IR [cm.sup.-1 ]______________________________________3.001 H CH.sub.3 H3.002 CH.sub.3 CH.sub.3 H3.003 H CH.sub.3 CH.sub.33.004 CH.sub.3 CH.sub.3 CH.sub.33.005 H CH.sub.2 CH.sub.3 H3.006 CH.sub.3 CH.sub.2 CH.sub.3 H3.007 H CH.sub.2 CH.sub.3 CH.sub.33.008 CH.sub.3 CH.sub.2 CH.sub.3 CH.sub.33.009 H (CH.sub.2).sub.2 CH.sub.3 H3.010 CH.sub.3 (CH.sub.2).sub.2 CH.sub.3 CH.sub.33.011 H (CH.sub.2).sub.2 CH.sub.3 CH.sub.33.012 CH.sub.3 (CH.sub.2 ).sub.2 CH.sub.3 CH.sub.33.013 H CH(CH.sub.3).sub.2 H3.014 CH.sub.3 CH(CH.sub.3).sub.2 H3.015 H CH(CH.sub.3).sub.2 CH.sub.3 oil 2978, 1720, 1512, 1437, 1097, 10683.016 CH.sub.3 CH(CH.sub.3).sub.2 CH.sub.33.017 H (CH.sub.2).sub.3 CH.sub.3 H3.018 CH.sub.3 (CH.sub.2).sub.3 CH.sub.3 H oil 1720, 1512, 1437, 11323.019 H (CH.sub.2).sub.3 CH.sub.3 CH.sub.33.020 CH.sub.3 (CH.sub.2).sub.3 CH.sub.3 CH.sub.3______________________________________

The herbicidal agents, or the active ingredients on which they are based, may be applied pre- or postemergence. If certain crop plants tolerate the active ingredients 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).

The application rates depend on the objective to be achieved, the time of the year, the plants to be combated and their growth stage, and are from 0.005 to 3.0, preferably 0.01 to 0.5, kg/ha.

The action of the active ingredients of the formula I on the growth of plants is illustrated in greenhouse experiments.

The vessels employed were plastic flowerpots having a volume of 300 cm.sup.3 and filled with a sandy loam containing about 3.0% humus. The seeds of the test plants were sown separately, according to species.

For the postemergence treatment, either plants which had been sown in the pots and grown there were selected, or they were cultivated separately as seedlings and transplanted to the pots a few days before being treated.

Depending on growth form, the plants were grown to a height of from 3 to 15 cm before being treated with the active ingredients which were suspended or emulsified in water and sprayed through finely distributing nozzles. The application rate for postemergence treatment was 0.06 kg/ha.

The pots were set up in the greenhouse, species from warmer climates in warmer areas (20.degree. to 35.degree. C.) and species from moderate climates at 10.degree. to 20.degree. C. The experiments were run for from 2 to 4 weeks. During this time the plants were tended and their reactions to the various treatments assessed.

The assessment scale was 0 to 100, 100 denoting nonemergence or complete destruction of at least the visible plant parts, and 0 denoting no damage or normal growth.

The plants used in the greenhouse experiments belonged to the following species:

______________________________________CODE Botanical name Common name______________________________________ABUTH Abutilon theophrasti velvet leafAMARE Amaranthus spp. pigweedCHYCO Chrysanthemum corinarium crown daisyDEDTO Desmodium tortuosum Florida beggarweedGALAP Galium aparine catchweed bedstrawIPOSS Ipomoea spp. morninggloryLAMAM Lamium amplexicaule henbitMERAN Mercurialis annua annual mercuryPOLPE Polygonum persicaria ladysthumbSINAL Sinapis alba white mustardSOLNI Solanum nigrum black nightshadeSTEME Stellaria media chickweedTRZAS Triticum aestivum spring wheatTRZAW Triticum aestivum wheatVERSS Veronica spp. speedwellZEAMX Zea mays Indian corn______________________________________

In view of the numerous application methods possible, the compounds according to the invention, or agents containing them, may be used in a large number of crop plants for removing unwanted plants. The following crops are examples:

______________________________________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,Coffea liberica) coffee plantsCucumis melo melonsCucumis sativus cucumbersCynodon dactylon BermudagrassDaucus carota carrotsElais guineensis oil palmsFragaria vesca strawberriesGlycine max soybeansGossypium hirsutum (Gossypium arboreum, cottonGossypium herbaceum, Gossypium vitifolium)Helianthus annuus sunflowersHelianthus tuberosus Jerusalem artichokeHevea brasiliensis rubber plantsHordeum vulgare barleyHumulus lupulus hopsIpomoea batatas sweet potatoes Juglans regia walnut treesLinum usitatissimum flaxLycopersicon lycopersicum tomatoesMalus spp. apple treesManihot esculenta cassavaMedicago sativa alfalfa (lucerne)Mentha piperita peppermintMusa spp. banana plantsNicotiana tabacum (N. rustica) tobaccoOlea europaea olive treesOryza sativa ricePhaseolus lunatus limabeansPhaseolus mungo mungbeansPhaseolus vulgaris snapbeans, green beans, dry beansPennisetum glaucum pearl milletPetroselinum crispum spp. tuberosum parsleyPicea 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 sorgoTheobroma cacao cacao plantsTrifolium pratense red cloverTriticum aestivum wheatVaccinium corymbosum blueberriesVaccinium vitis-idaea cranberriesVicia faba tick beans Vigna 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 N-phenyltetrahydrophthalimides of the formula I may be mixed with each other, or mixed and applied together with numerous representatives of other herbicidal or growth-regulating active ingredient groups. Examples of suitable components are diazines, 4H-3,1-benzoxazine derivatives, benzothiadiazinones, 2,6-dinitroanilines, N-phenylcarbamates, thiolcarbamates, halocarboxylic acids, triazines, amides, ureas, diphenyl ethers, triazinones, uracils, benzofuran derivatives, cyclohexane-1,3-dione derivatives, quinolinecarboxylic acids, etc.

It may also be useful to apply the N-phenyltetrahydrophthalimides of the formula I, 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 with solutions of mineral salts used to remedy nutritional or trace element deficiencies. Non-phytotoxic oils and oil concentrates may also be added.

TABLE 4______________________________________Herbicidal action of compound no. 1.027 on postemergenceapplication of 0.06 kg/ha in the greenhouseTest plants Damage (%)______________________________________ABUTH 100AMARE 100DEDTO 100GALAP 98IPOSS 100MERAN 100SOLNI 100______________________________________ TABLE 5______________________________________Herbicidal action and tolerance by a crop on postemergenceapplication of 0.03 kg/ha of compound no. 1.027Test plants Damage (%)______________________________________GALAP 100LAMAM 100MERAN 100POLPE 100SINAL 95STEME 100TRZAW 0VERSS 100______________________________________

Examples demonstrating the control of unwanted broadleaved plants and tolerance by a crop on postemergence application of 0.03 kg/ha in the greenhouse.

TABLE 6__________________________________________________________________________ ##STR10##Comp. no. R.sup.1 R.sup.2 R.sup.3 R.sup.4 R.sup.5 TRZAS CHYCO SOLNI GALAP STEME__________________________________________________________________________2.007 H Cl H CH(CH.sub.3).sub.2 CH.sub.3 10 100 100 100 902.009 H Cl H (CH.sub.2).sub.3 CH.sub.3 CH.sub.3 10 100 100 100 100__________________________________________________________________________ TABLE 7__________________________________________________________________________ ##STR11##Comp. no. R.sup.1 R.sup.2 R.sup.3 R.sup.4 R.sup.5 ZEAMX CHYCO LAMAM SOLNI STEME__________________________________________________________________________1.031 H Cl CH.sub.3 CH.sub.2 CH(CH.sub.3).sub.2 H 0 100 100 100 100__________________________________________________________________________ TABLE 8__________________________________________________________________________ ##STR12##Comp. no. R.sup.1 R.sup.2 R.sup.3 R.sup.4 R.sup.5 TRZAS CHYCO SOLNI VERSS__________________________________________________________________________1.005 H Cl CH.sub.2 CH.sub.3 CH.sub.3 H 10 100 100 100__________________________________________________________________________

Claims

1. An N-tetrahydrophthalimide of the general formula ##STR13## where R.sup.1 is hydrogen or halogen, R.sup.2 is halogen, R.sup.3 is hydrogen or C.sub.1 -C.sub.4 -alkyl, R.sup.4 is unsubstituted or C.sub.1 -C.sub.3 -alkoxy-substituted C.sub.1 -C.sub.8 -alkyl, C.sub.3 -C.sub.4 -alkenyl or C.sub.3 -C.sub.4 -alkynyl, and R.sup.5 is hydrogen or C.sub.1 -C.sub.4 -alkyl, independently of the steric configuration.

2. A herbicidal agent containing a compound of the formula as set forth in claim 1, and conventional inert auxiliaries, extenders and diluents.

3. A process for combating the growth of unwanted plants, wherein a herbicidally effective amount of an N-tetrahydrophthalimide as set forth in claim 1 is allowed to act on the plants and their habitat.

4. An N-tetrahydrophthalimide of the general formula ##STR14## where R.sup.1 is hydrogen or halogen, R.sup.2 is halogen, R.sup.3 is C.sub.1 -C.sub.4 -alkyl, R.sup.4 is unsubstituted or C.sub.1 -C.sub.3 -alkoxy substituted C.sub.1 -C.sub.8 -alkyl, C.sub.3 -C.sub.4 -alkenyl or C.sub.3 -C.sub.4 -alkynyl, and R.sup.5 is hydrogen or C.sub.1 -C.sub.4 -alkyl, independently of steric configuration.