Abstract:
N-Pyrazinyl-haloacetamide having insecticidal, herbicidal, or fungicidal activity. The compound has the general formula: ##STR1## wherein R is hydrogen, hydrocarbyl, halogen, epoxy, hydroxy, alkoxy, mercapto, alkylthio, nitro, cyano or amino; R&#39; is hydrogen or hydrocarbyl; X is halogen; m is an integer from 1 to 4; and n is 0, 1 or 2. The compound may also be a tautomer or acid addition salt of this formula.

Description:
FIELD OF THE INVENTION 
     The present invention is directed to N-pyrazinyl-haloacetamides which have biological activity as herbicides, insecticides, microbiocides or plant growth regulators. 
     DESCRIPTION OF THE INVENTION 
     The novel compounds of the present invention are N-pyrazinyl-haloacetamides of the formula: ##STR2## wherein each R is a radical independently selected from: hydrogen; hydrocarbyl radicals having from 1 to about 10 carbon atoms, preferably from 1 to about 6 carbon atoms; halide; epoxy; --OR&#34; in which R&#34; is hydrogen or a hydrocarbyl radical having from 1 to about 10 carbon atoms, preferably from 1 to about 6 carbon atoms; --SR&#34; in which R&#34; is hydrogen or a hydrocarbyl radical having from 1 to about 10 carbon atoms, preferably from 1 to about 6 carbon atoms; nitro; cyano; and --NR&#34; 2  in which each R&#34; is independently hydrogen or a hydrocarbyl radical having from 1 to about 10 carbon atoms, preferably from 1 to about 6 carbon atoms; 
     each R&#39; is independently hydrogen or hydrocarbyl radical having from 1 to about 10 carbon atoms, preferably from 1 to about 6 carbon atoms; 
     X is halogen selected from chlorine, bromine, fluorine and iodine, preferably chlorine; 
     n is an integer from 0 to 2; and 
     m is an integer from 1 to 4. The compounds of the invention also include the biologically active acid addition salts and tautomers corresponding to the foregoing formula. 
     Particularly preferred as having insecticidal activity for the family Tetranychidae (spider mites) are the N-pyrazinyl-haloacetamides of the above formula in which n is 2, e.g. 2-chloro-N-(2-pyrazinyl)-acetamide. 
     Particularly preferred as having herbicidal and plant growth regulating activity for broadleaf grasses, grassy weeds, and broadleaf crops are the N-pyrazinyl-haloacetamides of the above formula in which n is zero, e.g. 2,2,2-trichloro-N-(2-pyrazinyl)-acetamide. 
     The present N-pyrazinyl-haloacetamides are generally prepared by reacting 2-haloacetyl halide with the appropriate aminopyrazine in an inert organic solvent in the presence of an acid scavenger. Suitable inert solvents include, for example, ethyl acetate, ethyl ether, petroleum ether, tetrahydrofuran, acetonitrile, toluene, and the like. Typical acid scavengers include, for example, triethylamine, sodium carbonate, sodium bicarbonate, calcium carbonate, calcium bicarbonate, dimethyl benzylamine, sodium acetate, and the like. Generally, the reaction is carried out at room temperature and is completed in 1/2-4 hours with stirring. The product is generally recovered by evaporating the solvent following the reaction. 
     In using the present N-pyrazinyl-haloacetamides, it may be applied to the area to be treated in the form of wettable powder, dust, granules, solution, emulsion, suspension or aerosol as desired at an effective rate. 
    
    
     EXAMPLE 1 
     Into a 250 ml round-bottom flask equipped with a magnetic stirrer were placed 7.00 g (0.07 mol) aminopyrazine, 150 ml anhydrous ethyl acetate and 7.49 g (0.07 mol) triethylamine as an HCl scavenger. After complete dissolution of the aminopyrazine, an argon atmosphere was maintained and 8.36 g (0.07 mol) 2-chloroacetyl chloride was added with a syringe pump over a one-hour period while stirring. The reaction temperature was about 23°-25° C. After stirring for an additional one-half hour, the ethyl acetate was removed by vacuum distillation at room temperature to precipitate the reaction product. The product was dissolved and ultrasonicated in about 400 ml methylene chloride, washed with deionized water, dried over magnesium sulfate, and filtered. The methylene chloride was then removed by vacuum distillation at room temperature. 
     The product was a light green solid, m.p. 143°-145° C. The chemical structure for N-(2-pyrazinyl)-2-chloroacetamide was verified by NMR, IR and GC analytical methods. 
     The product was screened for insecticidal and herbicidal activity, and was found to have insecticidal activity for two-spotted spider mites. At 800 ppm, about 95 percent of the mites were killed. The results are presented in Table I. 
     
                       TABLE I______________________________________Biological Activity Screening of2-Chloro-N--pyrazinyl Acetamide          Test                 PercentSpecies        Method   Concentration                               Inhibition______________________________________Tobacco Budworm          .sup. A.sup.1                   800     ppm   0Beet Army worm larvae          A        800     ppm   0Western spotted cucumber          .sup. B.sup.2                   75      ppm   0beetle larvaeTwo-spotted spider mite          .sup. C.sup.3                   800     ppm   95Nutsedge       .sup. D.sup.4                   4000    ppm   0Pig weeds      D        4000    ppm   0Pig weeds      .sup. E.sup.5                   1.12    g/m.sup.2                                 0Cotton         D        4000    ppm   0Cotton         E        1.12    g/m.sup.2                                 0Crabgrass      D        4000    ppm   0Crabgrass      E        1.12    g/m.sup.2                                 0Water grass    D        4000    ppm   0Water grass    E        1.12    g/m.sup.2                                 0Wild oats      D        4000    ppm   0Wild oats      E        1.12    g/m.sup.2                                 0Yellow Foxtail D        4000    ppm   0Yellow Foxtail E        1.12    g/m.sup.2                                 0Velvet leaf    D        4000    ppm   0Velvet leaf    E        1.12    g/m.sup.2                                 0______________________________________Notes for Table I:.sup.1 Test Method A: Three-inch discs of the indicated leaf (tobaccoor beet) were treated in the diluted test material at theindicated concentration by spray or dip and placed in an openpetry dish until dry. Test insects were put onto the treatedleaf and the petry dish covered. Single mortality counts weremade and recorded 2-5 days after keeping the covered petry dishin a moist atmosphere..sup.2 Test Method B: Thirty grams of air-dried Davis soil were placedin a jar and treated with sufficient 800 ppm test chemicalsolution or dispersion to obtain the indicated concentration.The treated soil was dried for 24 hours and stirred well. In aplastic cup was placed 5 ml water, two corn seeds, 50-75 eggs,and the 30 g soil. The cup was capped with a plastic lid havinga 3 mm hole in the center and stored at 27° F. and 60% relativehumidity. The test was read 9-12 days later, noting live anddead larvae and any unhatched eggs..sup.3 Test Method C: Test plants were grown singly in three-inch potsand used before the primary leaves were fully expanded andbefore terminal growth occurred. Fifty to 100 mites or aphidsas indicated were placed on the host plant and the plant wasthen dipped in the test chemical solution at the indicatedconcentration. Also, an additional application of the testchemical was made to the soil by an injection of the testchemical solution at approximately 2.2 g/m.sup.2 with a syringe. Thetests were conducted under greenhouse conditions (18-36° C.) andmortality checks made 3-6 days following treatment. Percentcontrol was recorded after making any corrections for naturalmortality in untreated checks..sup.4 Test Method D: The indicated species were grown in plant bandsto an average height of about 4 inches and sprayed to runoffwith an aqueous solution or dispersion of the test chemical atthe indicated concentrations. The plants were then held ingreenhouse conditions for about 2 weeks before reading. Percentinhibition was determined by comparison to untreated plants, 0indicating no visible effect and 100 indicating all plants dead..sup.5 Test Method E: Seeds were planted in agricultural soil. Justafter planting the diluted test chemical was sprayed on the soilat the indicated rate to drench the soil and allow the chemicalto leach into the soil. The pots were maintained in variablegreenhouse conditions (18-36°  C.) and watered as necessary.Readings were taken about two weeks after treatment and percentinhibition determined as in Test Method E. 
    
     EXAMPLE 2 
     The procedure of Example 1 was repeated except that 10.90 g (0.07 mol) of 2,2-dichloroacetyl chloride was used instead of the 2-chloroacetyl chloride. The product N-(2-pyrazinyl)-2,2-dichloroacetamide was obtained as a brown semi-solid containing some unreacted aminopyrazine complexed therewith. The chemical structure was verified by NMR, IR and GC analytical techniques. 
     EXAMPLE 3 
     The procedure of Examples 1 and 2 was repeated except that 13.45 g (0.07 mol) of 2,2,2-trichloroacetyl chloride was used as the haloacetyl chloride. The product N-(2-pyrazinyl)-2,2,2-trichloroacetamide was obtained as a light tan solid, m.p. about 68° C., which also contained some unreacted aminopyrazine. The chemical structure was verified by NMR, IR and GC analytical methods. 
     The trichloro product was screened for biological activity as in Example 1, and was found to have pre-emergence herbicidal activity for various species. The results are presented in Table II. 
     
                       TABLE II______________________________________Biological Activity Screening of2,2,2-Trichloro-N--pyrazinyl Acetamide          Test                 PercentSpecies        Method   Concentration                               Inhibition______________________________________Tobacco budworm          .sup. A.sup.1                   800     ppm   0Beet army worm larvae          A        800     ppm   0West spotted cucumber          .sup. B.sup.2                   75      ppm   0beetle larvaeTwo-spotted spider mite          .sup. C.sup.3                   800     ppm   0Nutsedge       .sup. D.sup.4                   4000    ppm   0Nutsedge       .sup. E.sup.5                   0.11    g/m.sup.2                                 0Nutsedge       E        1.22    g/m.sup.2                                 70Pig weeds      D        4000    ppm   0Pig weeds      E        1.12    g/m.sup.2                                 0Cotton         D        4000    ppm   0Cotton         E        0.11    g/m.sup.2                                 0Cotton         E        0.22    g/m.sup.2                                 30Cotton         E        1.12    g/m.sup.2                                 0Crabgrass      D        4000    ppm   0Crabgrass      E        1.12    g/m.sup.2                                 0Water grass    D        4000    ppm   0Water grass    E        0.22    g/m.sup.2                                 0Water grass    E        1.22    g/m.sup.2                                 100Wild oats      D        4000    ppm   0Wild oats      E        1.12    g/m.sup.2                                 100Yellow foxtail D        4000    ppm   0Yellow foxtail E        0.22    g/m.sup.2                                 0Yellow foxtail E        1.22    g/m.sup.2                                 100Velvet leaf    D        4000    ppm   0Velvet leaf    E        0.22    g/m.sup.2                                 0Velvet leaf    E        1.12    g/m.sup.2                                 0Morning glory  D        4000    ppm   0Morning glory  E        0.22    g/m.sup.2                                 0Morning glory  E        1.22    g/m.sup.2                                 0Soybean        E        0.22    g/m.sup.2                                 0White winter wheat          E        0.03    g/m.sup.2                                 0White winter wheat          E        0.06    g/m.sup.2                                 50White winter wheat          E        0.11    g/m.sup.2                                 50White winter wheat          E        0.22    g/m.sup.2                                 50Corn           E        0.11    g/m.sup.2                                 0Corn           E        0.22    g/m.sup.2                                 50Sorghum/milo   E        0.11    g/m.sup.2                                 0Sorghum/milo   E        0.22    g/m.sup.2                                 30Johnson grass  E        0.22    g/m.sup.2                                 0Sugar beets    E        0.22    g/m.sup.2                                 0Rape           E        0.11    g/m.sup.2                                 0Rape           E        0.22    g/m.sup.2                                 40Cultured rice  E        0.11    g/m.sup.2                                 0Cultured rice  E        0.22    g/m.sup.2                                 100Jimson weed    E        0.22    g/m.sup.2                                 0Species 19184  E        0.11    g/m.sup.2                                 0Species 19184  E        0.22    g/m.sup.2                                 20______________________________________ Notes for Table II: .sup.1 See Table I, note 1. .sup.2 See Table I, note 2. .sup.3 See Table I, note 3. .sup.4 See Table I, note 4. .sup. 5 See Table I, note 5. 
    
     Having described my invention above, many variations in the illustrated details and specific materials, apparatus and procedures will occur to those skilled in the art. It is intended that all such variations which fall within the scope and spirit of the claims which follow be embraced thereby.