Patent Publication Number: US-4728357-A

Title: Cyclohexane-1,3-dione derivatives, their preparation and herbicides containing these compounds

Description:
This application is a continuation of application Ser. No. 515,897, filed on July 21, 1983, now abandoned. 
    
    
     It has been disclosed that, for example, 2-(1-ethoxyaminobutylidene)-5-(2-ethylthiopropyl)-cyclohexane-1,3-dione and other compounds of this type possessing a lower alkyl or phenyl group at the sulfur atom have a good action against grasses (U.S. Pat. No. 4,249,937 and British Pat. No. 2,090,246). 
     We have found that the compounds as claimed in claim 1 likewise have a herbicidal action against grasses, and moreover cause little or no damage either to broad-leaved crop plants and monocotyledon crops, which do not belong to the family of grasses (Gramineae), or, surprisingly, to cereals. 
     The novel compounds of the formula I can occur in various tautomeric forms, all of which are embraced by the claims: ##STR2## In formula I R 1  is branched or straight-chain alkyl of 2 to 4 carbon atoms, e.g. ethyl, n-propyl, i-propyl or n-butyl, R 2  is alkyl or alkenyl of 2 or 3 carbon atoms, for example ethyl, allyl, n-propyl, i-propyl, R 3  is ethylene which is unsubstituted or substituted by 1 to 2 substituents selected from the group consisting of methyl, phenyl, benzyl and C 2  -C 6  -alkenyl, the substituents totaling a maximum of 7 carbon atoms, or R 3  is propenylene, R 4  is, when R 3  is unsaturated or olefinically or aromatically substituted, alkyl of from 1 to 6 carbon atoms, R 4  is further alkenyl of from 2 to 6 carbon atoms, phenyl, chlorophenyl, naphthyl or phenylethyl, Z=H, and n i O, or a salt thereof. 
     Examples of suitable salts of the compounds of the formula I are the alkali metal salts, in particular potassium or sodium salts, alkaline earth metal salts, in particular calcium, magnesium or barium salts, and manganese salts, copper salts, zinc salts and iron salts. 
     The anion A.sup.⊖ of the hydroxylammonium salt referred to in claim 2 is a monovalent anion or one equivalent of a polyvalent anion, e.g. Cl - , Br - , 1/2 SO 4   --  or H 3  C--COO - . 
     Preparation 
     The novel derivatives I can be prepared by the methods described below: ##STR3## In the formulae, R 1 , R 2 , R 3 , R 4 , Z and A have the above meanings. 
     The reaction is advantageously carried out in the heterogeneous phase at from 0° to 80° C. in an inert solvent in the presence of a base. Examples of suitable bases are carbonates, bicarbonates, acetates, alcoholates, hydroxides or oxides of alkali metals or alkaline earth metals, in particular of sodium, potassium, magnesium or calcium. Organic bases, e.g. pyridine or tertiary amines, may also be used. A defined pH of from 2 to 8, in particular from 4.5 to 5.5, is particularly suitable for the reaction, this pH advantageously being established by the addition of an acetate, eg. sodium acetate or potassium acetate, or of a bicarbonate, eg. sodium bicarbonate or potassium bicarbonate. The base is used in an amount of from 0.5 to 2 moles, based on the hydroxylammonium compound. Examples of suitable solvents are dimethylsulfoxide, alcohols, such as methanol, ethanol and isopropanol, benzene, toluene, hydrocarbons and chlorohydrocarbons, such as methylene chloride, chloroform or dichloroethane, esters, such as ethyl acetate, and ethers, such as dioxane, tetrahydrofuran or diethyl ether. The reaction is complete after a few hours, and the product can be obtained by evaporating down the reaction mixture, adding water, extracting the mixture with a non-polar solvent, eg. methylene chloride, and distilling off the solvent under reduced pressure. 
     The compounds of the formula I can also be obtained by reacting a compound II with a hydroxylamine of the formula R 2  ONH 2 , or an aqueous solution of this, in an inert solvent under the conditions described above. 
     Furthermore, the novel compounds can be prepared by reacting a compound of the formula II with hydroxylamine to give an oxime, and alkylating the latter with a suitable alkylating agent to give the novel end product: ##STR4## The compounds of the formula II can be obtained by C-acylation of a cyclohexane-1,3-dione(III), as described in Tetrahedron Lett. (1975), page 2491. In another suitable method of preparing the derivatives II, a cyclohexane-1,3-dione (III) is C-acylated and the product is then subjected to a rearrangement reaction under acid catalysis (AlCl 3 , as described in Synthesis (1978), page 925) or base catalysis (pyridine derivatives, as described in Japanese Pat. No. 54,063,052). 
     The compounds III can also occur in the tautomeric forms III a/b shown below: ##STR5## 
     Compounds of the formula III can be prepared from an aldehyde R 4  --SO n  --R 3  --CH═O by a conventional method, for example by aldol condensation with acetone followed by cyclisation with a malonate by a procedure similar to that described in Organic Synthesis Coll. Vol. II, page 200. The intermediates of the formula III can also be obtained by reacting an aldehyde R 4  SO n  R 3  --CHO with malonic acid by the Knoevenagel-Doebner reaction (cf. Org. Reaction Vol. 15, page 204), esterifying the resulting acid and subjecting the product to a cyclization reaction with ethyl acetoacetate, the procedure used being similar to that described in, for example, Chem. Ber. 96 (1963), page 2946. 
     The aldehydes R 4  --SO n  --R 3  CHO can be obtained by an addition reaction of a mercaptan with an unsaturated aldehyde (German Pat. No. 855,704). Another possible method of synthesizing the compounds III comprises reacting a γ-halocrotonic acid derivative with a mercaptan and subjecting the resulting γ-mercaptocrotonic acid derivative to a cyclization reaction with ethyl acetoacetate, as described above. 
     The sodium and potassium salts of the novel compounds can be obtained by treating these compounds with sodium hydroxide or potassium hydroxide in aqueous solution or in an organic solvent, e.g. methanol, ethanol or acetone. The base used may also be an alkali metal alcoholate. 
     Other metal salts, e.g. the manganese, copper, zinc, iron or barium salts, can be prepared by reacting the sodium salt with the appropriate metal chloride in aqueous solution. 
    
    
     The Examples which follow illustrate the preparation of the novel cyclohexanediones. Parts are by weight, and parts by weight bear the same relation to parts by volume as that of the kg to the liter. 
     EXAMPLE 1 
     10.6 parts by weight of 2-butyryl-4-methoxycarbonyl-5-(2-allylthiopropyl)-cyclohexane-1,3-diol are dissolved in 150 parts by volume of ethanol, 3.3 parts by weight of allyloxiammonium chloride and 2.9 parts by weight of sodium acetate are added and the mixture is stirred for 20 hours at room temperature. Thereafter, the mixture is poured into ice water, the resulting mixture is extracted with methylene chloride and the latter is stripped off to give 11.3 g of 2-(1-allyloxibutylidene)-4-methoxycarbonyl-5-(2-allylthiopropyl)-cyclohexane-1,3-dione as a yellow oil. 
     
         ______________________________________                                    
 ##STR6##                                                                 
C.sub.21 H.sub.31 NO.sub.5 S  M = 409 n.sub.D.sup.25 1,5337               
______________________________________                                    
calculated: C 61.5  H 7.6      N 3.4 S 7.8                                
found:      C 61.7  H 7.7      N 3.1 S 8.2                                
______________________________________                                    
 
    
     The following compounds may be prepared analogously: 
     
         __________________________________________________________________________
 ##STR7##                                                                 
Com-                                                                      
pound                                                    Refractive       
no. R.sup.1                                                               
        R.sup.2   R.sup.3S            R.sup.4  Z      n  index            
                                                         (°C.)     
__________________________________________________________________________
1   n-C.sub.3 H.sub.7                                                     
        CH.sub.2 CHCH.sub.2                                               
                   ##STR8##           CH.sub.2 CHCH.sub.2                 
                                               COOCH.sub.3                
                                                      0  1.5337 (25)      
2   &#34;   C.sub.2 H.sub.5                                                   
                  &#34;                   &#34;        &#34;      0  1.5325 (25)      
3   &#34;   C.sub.2 H.sub.5                                                   
                  &#34;                   &#34;        H      0  1.5397 (25)      
4   &#34;   CH.sub.2 CHCH.sub.2                                               
                  &#34;                   &#34;        H      0  1.5408 (25)      
5   &#34;   CH.sub.2 CHCHCl                                                   
                  &#34;                   &#34;        H      0                   
6   &#34;   CH.sub.2 CClCH.sub.2                                              
                  &#34;                   &#34;        H      0                   
7   &#34;   C.sub.2 H.sub.5                                                   
                  &#34;                   &#34;        H      1                   
8   &#34;   C.sub.2 H.sub.5                                                   
                  &#34;                   &#34;        H      2                   
9   &#34;   C.sub.2 H.sub.5                                                   
                  &#34;                   CH.sub.2 CH.sub.2 C.sub.6 H.sub.5   
                                               COOCH.sub.3                
                                                      0                   
10  &#34;   CH.sub.2 CHCH.sub.2                                               
                  &#34;                   &#34;        COOCH.sub.3                
                                                      0  1.5556 (25)      
11  &#34;   C.sub.2 H.sub.5                                                   
                  &#34;                   &#34;        H      0                   
12  &#34;   CH.sub.2 CHCH.sub.2                                               
                  CH.sub.2 CH(CH.sub.3)                                   
                                      CH.sub.2 CH.sub.2 C.sub.6 H.sub.5   
                                               H      0                   
13  &#34;   CH.sub.2 CHCHCl                                                   
                  &#34;                   &#34;        H      0                   
14  &#34;   CH.sub.2 CClCH.sub.2                                              
                  &#34;                   &#34;        H      0                   
15  &#34;   C.sub.2 H.sub.5                                                   
                  &#34;                   &#34;        H      1                   
16  &#34;   C.sub.2 H.sub.5                                                   
                  &#34;                   &#34;        H      2                   
17  &#34;   C.sub.2 H.sub.5                                                   
                  CH.sub.2 CH(C.sub.6 H.sub.5)                            
                                      C.sub.2 H.sub.5                     
                                               H      0  1.5628 (31)      
18  &#34;   CH.sub.2 CHCH.sub.2                                               
                  &#34;                   &#34;        H      0  2.5662 (31)      
19  &#34;   C.sub.2 H.sub.5                                                   
                  CH.sub.2 C(CH.sub.3)CH.sub.2 CH.sub.2 CHC(CH.sub.3).sub.
                  2                   &#34;        H      0  1.5192 (31)      
20  &#34;   CH.sub.2 CHCH.sub.2                                               
                  &#34;                   &#34;        H      0                   
21  &#34;   C.sub.2 H.sub.5                                                   
                  CH.sub.2 C(CH.sub.3)CH.sub.2 CH.sub.2 CHC(CH.sub.3).sub.
                  2                   C.sub.6 H.sub.4                     
                                               H      0                   
22  &#34;   CH.sub.2 CHCH.sub.2                                               
                  &#34;                   C.sub.6 H.sub.5                     
                                               H      0                   
23  &#34;   C.sub.2 H.sub.5                                                   
                  &#34;                   p-ClC.sub.6 H.sub.4                 
                                               H      0                   
24  &#34;   CH.sub.2 CHCH.sub.2                                               
                  &#34;                   p-ClC.sub.6 H.sub.4                 
                                               H      0                   
25  &#34;   CH.sub.2 CHCHCl                                                   
                  &#34;                   C.sub.2 H.sub.5                     
                                               H      0                   
26  &#34;   CH.sub.2 CClCH.sub.2                                              
                  &#34;                   C.sub.2 H.sub.5                     
                                               H      0                   
27  &#34;   C.sub.2 H.sub.5                                                   
                  CHCHCH.sub.2         C.sub.2 H.sub.5                    
                                               H      0                   
28  &#34;   CH.sub.2 CHCH.sub.2                                               
                  CHCHCH.sub.2        C.sub.2 H.sub.5                     
                                               H      0                   
29  &#34;   C.sub.2 H.sub.5                                                   
                  CH.sub.2CHCH        C.sub.2 H.sub.5                     
                                               H      0                   
30  &#34;   CH.sub.2CHCH.sub.2                                                
                  CH.sub.2CHCH        C.sub.2 H.sub.5                     
                                               H      0                   
31  C.sub.2 H.sub.5                                                       
        C.sub.2 H.sub.5                                                   
                  CH.sub.2 CH(CH.sub.3)                                   
                                      CH.sub.2 CH.sub.2 C.sub.6 H.sub.5   
                                               H      0                   
32  C.sub.2 H.sub.5                                                       
        CH.sub.2 CHCH.sub.2                                               
                  CH.sub.2 CH(CH.sub.3)                                   
                                      CH.sub.2 CH.sub.2 C.sub.6 H.sub.5   
                                               H      0                   
33  C.sub.2 H.sub.5                                                       
        CH.sub.2 CHCHCl                                                   
                  CH.sub.2 CH(CH.sub.3)                                   
                                      CH.sub.2 CH.sub.2 C.sub.6 H.sub.5   
                                               H      0                   
34  C.sub.2 H.sub.5                                                       
        CH.sub.2 CClCH.sub.2                                              
                  CH.sub.2 CH(CH.sub.3)                                   
                                      CH.sub.2 CH.sub.2 C.sub.6 H.sub.5   
                                               H      0                   
35  n-C.sub.3 H.sub.7                                                     
        C.sub.2 H.sub.5                                                   
                  CH.sub.2 CH(CH.sub.3 )                                  
                                      CH.sub.2 CH.sub.2 C.sub.6 H.sub.5   
                                               CH.sub.3                   
                                                      0                   
36  n-C.sub.3 H.sub.7                                                     
        C.sub.2 H.sub.5                                                   
                  CH.sub.2 CH(CH.sub.3)                                   
                                      CH.sub.2 CH.sub.2 C.sub.6 H.sub.5   
                                               CN     0                   
37  n-C.sub.3 H.sub.7                                                     
        C.sub.2 H.sub.5                                                   
                  CH.sub.2CH(CH.sub.2 C.sub.6 H.sub.5)                    
                                      C.sub.2 H.sub.5                     
                                               H      0                   
38  &#34;   &#34;         CH.sub.2CH(CH.sub.3)                                    
                                      β-naphthyl                     
                                               H      0  1.5921           
__________________________________________________________________________
                                                         (37)             
 
    
     Application 
     The agents may be applied pre- or postmergence. Preferably, the novel active ingredients are applied after emergence of the unwanted plants. 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 amount of active ingredient applied depends on the time of the year, the objective to be achieved, the plants to be combated, and the growth stage of the plants, and varies from 0.05 to 5 kg/ha. 
     The influence of representatives of the novel cyclohexane-1,3-dione derivatives on the growth of unwanted and crop plants is demonstrated in greenhouse experiments. 
     The vessels employed were plastic flowerpots having a volume of 300 cm 3 , and which were filled with a sandy loam containing about 1.5% humus. The seeds of the test plants were sown shallow, and separately, according to species. For the preemergence treatment, the active ingredients were applied to the surface of the soil immediately after the seeds had been sown. The compounds were emulsified or suspended in water as vehicle, and sprayed through finely distributing nozzles. The application rate was 3.0 kg of active ingredient per hectare. After the agents had been applied, the vessels were lightly sprinkler-irrigated to induce germination and growth and to active the chemical agents. Transparent plastic covers were then placed on the vessels until the plants had taken root. The cover ensured uniform germination of the plants, insofar as this was not impaired by the active ingredients. 
     For the postemergence treatment, the plants were first grown in the vessels to a height of from 3 to 15 cm, depending on growth form, before being treated. The soybean plants used for the postemergence treatment were grown in a peat-enriched substrate to ensure better growth than is possible in a sandy loam. For this treatment, plants which had been sown directly in the pots and grown there were selected. No covers were placed on the pots in this treatment method. The application rates for postemergence treatment varied from ingredient to ingredient, and were 0.125, 0.25 and 3.0 kg of active ingredient per hectare. 
     The following compound was used for comparison purposes at a rate of 0.25 kg/ha: ##STR9## 
     The following test plants were used in the experiments: 
     
         ______________________________________                                    
Botanical name       Common name                                          
______________________________________                                    
Alopecurus myosuroides                                                    
                     blackgrass                                           
Avena fatua          wild oats                                            
Echinochloa crus-galli                                                    
                     barnyardgrass                                        
Glycine max.         soybeans                                             
Lolium multiflorum   Italian ryegrass                                     
Hordeum vulgare      barley                                               
Triticum aestivum    wheat                                                
Oryza sativa         rice                                                 
______________________________________                                    
 
    
     The pots were set up in the greenhouse--species from warmer areas at from 20° to 35° C., and species from moderate climates at 10° to 20° C. The experiments were run for 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 0 to 100, 0 denoting no damage or normal emergence, and 100 denoting nonemergence or complete destruction of at least the visible plant parts. 
     On pre- and postemergence application in the greenhouse, compounds nos. 3, 4, 11 and 12 had a considerable herbicidal action on grassy species. 
     In investigations in the greenhouse into selective herbicidal action, compound no. 19 combated unwanted grassy species at 0.25 kg/ha. No damage was inflicted on the soybean plants or on the cereals barley and wheat. The herbicidal action of comparative agent A is somewhat stronger, but even lower (still effective) application rates do not achieve the tolerance of compound no. 19 according to the invention. 
     On postemergence application in the greenhouse, compound no. 17, at 0.125 kg/ha, exhibited good control of unwanted plants, without damaging crop plants such as soybeans and wheat. The damage caused to Glycine max. and Triticum aestivum was 0%, to Alopecurus myosuroides 80%, and to Avena fatua and Lolium multiflorum 90%. 
     Further, compound no. 11, applied postemergence at a rate of 0.06 kg/ha, selectively combated unwanted grasses (88% damage to Echinochloa crus-galli) in rice (Oryza sativa; 5% damage). 
     Compound no. 18, applied in the greenhouse at 0.125 kg/ha, controlled wild oats very well (Avena fatua; 95% damage) while causing only little damage to wheat (Triticum aestivum; 10% damage). 
     In view of the good tolerance of the herbicides according to the invention, or agents containing them, by numerous broadleaved and other crops, and the numerous application methods possible, they may be used in a large number of crops for removing unwanted plant growth. 
     The following crops may be mentioned by way of example: 
     
         ______________________________________                                    
Botanical name    Common name                                             
______________________________________                                    
Allium cepa       onions                                                  
Ananas comosus    pineapples                                              
Arachis hypogaea  peanuts (groundnuts)                                    
Asparagus officinalis                                                     
                  asparagus                                               
Beta vulgaris spp. altissima                                              
                  sugarbeets                                              
Beta vulgaris spp. rapa                                                   
                  fodder beets                                            
Beta vulgaris spp. esculenta                                              
                  table beets, red beets                                  
Brassica napus var. napus                                                 
                  rape                                                    
Brassica napus var. napobrassica                                          
Brassica napus var. rapa                                                  
                  turnips                                                 
Brassica rapa var. silvestris                                             
Camellia sinensis tea plants                                              
Carthamus tinctorius                                                      
                  safflower                                               
Carya illinoinensis                                                       
                  pecan trees                                             
Citrus limon      lemons                                                  
Citrus maxima     grapefruits                                             
Citrus reticulata mandarins                                               
Citrus sinensis   orange trees                                            
Coffea arabica (Coffea canephora,                                         
                  coffee plants                                           
Coffea liberica)                                                          
Cucumis melo      melons                                                  
Cucumis sativus   cucumbers                                               
Cynodon dactylon  Bermudagrass in turf                                    
                  and lawns                                               
Daucus carota     carrots                                                 
Elais guineensis  oil palms                                               
Fragaria vesca    strawberries                                            
Glycine max       soybeans                                                
Gossypium hirsutum                                                        
                  cotton                                                  
(Gossypium arboreum                                                       
Gossypium herbaceum                                                       
Gossypium vitifolium)                                                     
Helianthus annuus sunflowers                                              
Helianthus tuberosus                                                      
Hevea brasiliensis                                                        
                  rubber plants                                           
Hordeum vulgare   barley                                                  
Humulus lupulus   hops                                                    
Ipomoea batatas   sweet potatoes                                          
Juglans regia     walnut trees                                            
Lactuca sativa    lettuce                                                 
Lens culinaris    lentils                                                 
Linum usitatissimum                                                       
                  flax                                                    
Lycopersicon lycopersicum                                                 
                  tomatoes                                                
Malus spp.        apple trees                                             
Manihot esculenta cassava                                                 
Medicago sativa   alfalfa (lucerne)                                       
Mentha piperita   peppermint                                              
Musa spp.         banana plants                                           
Nicothiana tabacum                                                        
                  tobacco                                                 
(N. rustica)                                                              
Olea europaea     olive trees                                             
Oryza sativa      rice                                                    
Phaseolus lunatus limabeans                                               
Phaseolus mungo   mungbeans                                               
Phaseolus vulgaris                                                        
                  snapbeans, green beans,                                 
                  dry beans                                               
Pennisetum glaucum                                                        
Petroselinum crispum                                                      
                  parsley                                                 
spp. tuberosum                                                            
Picea abies       Norway spruce                                           
Abies alba        fir trees                                               
Pinus spp.        pine trees                                              
Pisum sativum     English peas                                            
Prunus avium      cherry trees                                            
Prunus domestica  plum trees                                              
Prunus dulcis     almond trees                                            
Prunus persica    peach trees                                             
Pyrus communis    pear trees                                              
Ribes sylvestre   redcurrants                                             
Ribes uva-crispa  gooseberries                                            
Ricinus communis  castor-oil plants                                       
Saccharum officinarum                                                     
                  sugar cane                                              
Sesamum indicum   sesame                                                  
Solanum tuberosum Irish potatoes                                          
Spinacia oleracea spinach                                                 
Theobroma cacao   cacao plants                                            
Trifolium pratense                                                        
                  red clover                                              
Triticum aestivum wheat                                                   
Vaccinium corymbosum                                                      
                  blueberries                                             
Vaccinium vitis-idaea                                                     
                  cranberries                                             
Vicia faba        tick beans                                              
Vigna sinensis ( V. unguiculata)                                          
                  cow peas                                                
Vitis vinifera    grapes                                                  
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     To increase the sepctrum of action and to achieve synergistic effects, the novel cyclohexane-1,3-dione derivatives may be mixed and applied together with numerous other herbicidal active ingredients. Examples of suitable mixture 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, 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 with solutions of mineral salts used to remedy nutritional or trace element deficiencies. non-phytotoxic oils and oil concentrates may also be added. 
     
                                           TABLE 1                                 
__________________________________________________________________________
Herbicidal action of compounds according to the invention on pre-         
and postemergence application of 3.0 kg/ha in the greenhouse.             
 ##STR10##                                                                
                                           Test plants and % damage       
                                           Preemergence                   
                                                     Postemergence        
                                                 Lolium    Lolium         
Compound                                   Echinochloa                    
                                                 multi-                   
                                                     Echinochloa          
                                                           multi-         
no.   R.sup.1                                                             
          R.sup.2  SR.sup.3                                               
                           n R.sup.4     Z crus-galli                     
                                                 florum                   
                                                     crus-galli           
                                                           florum         
__________________________________________________________________________
11    n-C.sub.3 H.sub.7                                                   
          C.sub.2 H.sub.5                                                 
                    ##STR11##                                             
                           0 C.sub.6 H.sub.5CH.sub.2CH.sub.2              
                                         H 100   100 100     90           
12    n-C.sub.3 H.sub.7                                                   
          CH.sub.2 CHCH.sub.2                                             
                   &#34;       0 &#34;           H 100   100 100    90            
 3    n-C.sub.3 H.sub.7                                                   
          C.sub.2 H.sub.5                                                 
                   &#34;       0 CH.sub.2CHCH.sub.2                           
                                         H 100   100 100   100            
 4    n-C.sub.3 H.sub.7                                                   
          CH.sub.2 CHCH.sub.2                                             
                   &#34;       0 &#34;           H 100   100 100   100            
__________________________________________________________________________
 
    
     
                       TABLE 2                                                     
______________________________________                                    
Selective herbicidal action of compound no. 19                            
and comparative agent A on postemergence                                  
application in the greenhouse                                             
 ##STR12##                                                                
               Percentage damage at 0.25 kg/ha                            
Test plants      no. 19     A (prior art)                                 
______________________________________                                    
Glycine max.      0          0                                            
Hordeum vulgare   0         90                                            
Triticum aestivum                                                         
                  0         90                                            
Alopecurus myosuroides                                                    
                 90         95                                            
Avena fatua      90         95                                            
Lolium multiforum                                                         
                 90         98                                            
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