S-BENZYL THIOLCARBAMATES AND THEIR USE IN CONTROLLING WEEDS IN RICE FIELDS

Abstract: Novel S-benzyl thiolcarbamates, having the formula <IMAGE> in which R<1> is selected from the group consisting of hydrogen and methoxy, R<2> is selected from the group consisting of methyl, ethyl, and allyl, and R<3> is selected from the group consisting of straight-chain C3-C6 alkyl optionally substituted with one or two methyl groups, and allyl. The compounds are particularly effective in the control of weeds associated with rice crops.

Description: S-EEKZIL THIOLCAR-BA -CES ASP THEIR USE IN CONTROLLING- WEEDS IN RICE FIELDS Background of the Invention 1. Field of the Invention The inhibition of crop growth by weeds and other vegetation which consume valuable acreage or soil nutrients is a recurring problem in agriculture. To combat this problem, an extensive variety of chemi¬ cals and chemical formulations have been produced for application as herbicides- Many types of herbicides are disclosed in the literature and a large number are in commercial use. Prominent among the herbicides are the thiolcarbamates, several closely related a a og of which are well established in commercial use. The present invention resides in the discovery of a novel class of thiol- carbamates, i.e., certain S-benzyl thiolcarbamates, which display unusu¬ ally strong ef ectiveness in controlling weeds without harming the crop itself. 2. Description of the Prior Art S-Benzyl thiolcarbamates are known as herbicidal agents in gen¬ eral. References disclosing such compounds include U.S. Patent Nos. 3,679,726 ( udamatsu et al. , July 25, 1972), 3,144,475 (Har an et al. , August 11, 1964), 3,682,616 ( i ura et al., August 8, 1972), 3,781,440 (Marco et al., December 25, 1973), 3,992,185 (D'Amico, ovember 16, 1976), 4,153,444 (Jikihara et al., May 8, 1979), 3,742,005 (Tilles, June 26, 1973), 3,582,314 ( onnai et al., June 1, 1971), and 3,930,838 (Pellegrini et al., January 6, 1976), and Ger. Offen. 2,138,017 (Aya et al., February 3, 1972). Sι * τι-mnι-y of the Invention It has now been discovered that a certain class of S-benzyl thiolcarbamates display unusual activity in the control of weeds associ¬ ated with rice crops. This class of compounds is defined by the follow¬ ing formula in which R 1 is selected from the group consisting of hydrogen and metho-xy, R2 is selected from the group consisting of methyl, ethyl, and allyl, and R.3 is selected from the group consisting of C3-C6 alkyl optionally substituted with one or two methyl groups, and allyl. Within the scope of the present invention, certain embodiments are preferred, namely those in which R--- is selected from the group consisting of hydrogen and ethosy, R2 is selected from the group consisting of methyl, ethyl, and allyl, and R-5 is selected from the group consisting of n-butyl, n-pentyl, 1,2-dimethylpropyl, and allyl. Detailed Description of the Invention S-Eenzyl thiolcarbamates within the scope of the present inven¬ tion can be prepared by any of the known techniques for thiolcarbamate manufacture. These include the reaction between a benzyl chlorothiolfor- ate, a secondary amine, and a base; the reaction between a carbamyl chloride and a benzyl mercaptan: and the reaction between a secondary amine, carbonyl sulfide, and a base, to form an intermediate which is in turn reacted with a benzyl halide or sulfate. OMPI The following are- examples of the preparation of several com¬ pounds within the scope of the invention, followed by demonstrations of their efficacy in the control of weeds in rice fields. EXAMPLE 1 S-Benzyl Ethyl-1 ;2-dimethylpropylthiolcarbamate A reaction mole) of ethyl 1,2-dimethylpropyl amine, 5-6 g (0.055 mole) of triethylamine, and 75 ml of benzene. Once the amines were dissolved, the mixture was cooled to 0 β C. A solution of 9-3 g (0.050 mole) of benzyl chlorothiolformate in 25 ml of benzene was separately prepared and added in portions to the amine mixture. The temperature rose to approximately 40°C during the addition and a precipitate formed (triethylamine hydrochloride). After standing for several hours at room temperature, the mixture was filtered to remove the precipitate. The filtrate was washed with successive portions of 10^ hydrochloric acid and water, then dried with magnesium sulfate. The sol¬ vent was then evaporated on a rotary evaporator under vacuum to yield 12.1 g ( 1$ yield) of a liquid with refractive index n ** -30 = 1.5344, confirmed by infrared spectroscopy as. S-benzyl ethyl-l,2-dimethylpropyl- ' thiolcarbamate. EXAMPLE 2 S-Benzyl Ethyl-n-butylthiolcarbama,te The procedure of -E-xample 1 was followed, using 6.4 g (0.063 mole) of ethyl n-butyl amine, 6.7 g (0.066 mole) of 1_riethyl--_mine, and 11.2 g (0.060 mole) of ' benzyl chlorothiolfoπnate. Evaporation of the solvent yielded 13.1 g (87# yield) of a liquid with refractive index nτ)30 = 1.5367, confirmed by infrared spectroscopy as S-benzyl erthyl- n-butylthiolcarbamate. EXAMPLE 3 S-Benzyl Methyl-n-pentylthiolcarbamate A reaction vessel was charged witii 10.6 g (0.105 mole) of methyl-n-pentylamine, 11.1 g (0.11 mole) of triethylamine, and 200 ml of diethyl ether. The flask and contents were then placed in an ice bath. Over a five-minute period, 18.6 g (0.10 mole) of benzyl chlorothiolfor- mate were added through a dropper. The flask and contents were then removed from the ice bath, and heat was applied to reflux the reaction mixture at 36°C for thirty minutes. The mixture was cooled to rocm tem¬ perature and filtered to remove precipitated matter. The filtrate was washed with dilute hydrochloric acid and water and dried over magnesium sulfate, and the solvent was removed an a rotary evaporator under vacuum, and the residue was distilled in a falling film still at 165°C to yield 19.5 g ( 711*1%) of a liquid, with refractive index nj)30 = 1.5376, confirmed by mass spectroscopy as S-benzyl methyl-n-pentyltiiiolcarbaπ-ate. EXAMPLE 4 S-^enzyl Ethyl-n-pentylthiolcarbaroate The procedure of Exaπ-ple 3 was followed, using 12.1 g (0.105 mole) of ethyl-N-pentylamine, 11.1 (0.11 mole) of triethylamine, 200 ml of diethyl ether, and 18.6 g (0.10 mole) of benzyl chlorothiolfoππate. The liquid remaining after evaporation of the solvent was distilled in a falling film still at 165°C to produce a distillate weighing 23-5 g (88.8? yield), with refractive index nj * )30 = 1.5326, confirmed by mass spectroscopy as S-benzyl ethylHrt-pentylthiolcarbamate. O EXAMPLE 5 S-p-Metho-sybenzyl iall lthiolcarbamate The procedure of Example 1 was followed, using 3-0 g (0.03 mole) of diaUyla ine, 3-1 g (0.03 mole) of triethylamine, 50 ml of ben¬ zene, and 6.5 g (0.03 mole) of p-^ethoxybenzylchlorothiolformate. A liquid product weighing 7-6 g ( 1$ yield) with refractive index ΠD-50 = 1.5380 was achieved, confirmed by infrared spectroscopy as S-p-methoxybenzyl diallylthiolcarbamate. EXAMPLE 6 S-Benzyl Methyl-n-butylthiolcarbamate A stirred suspension of 4-7 g (0.054 mole) of methyl-n-butyl- a ine in 100 ml of water containing 2.2 g (0.054 mole) of sodium hydrox¬ ide was treated with 10 g (0.054 mole) of benzyl chlorothiolformate, the latter added rapidly in dropwise manner. During the addition and for an hour thereafter, the mixture was stirred constantly and held to a temper¬ ature of 0-10"C by external cooling. To the mixture was then added 100 " ml of diethyl ether. The liquid layers were then separated and the ether layer was dried over magnesium sulfate. The solvent was then evaporated to yield 11.45 g of a colorless liquid, determined by gas-liquid chroma- tography to be 97 pure product. The above compounds are summarized in the following table: ' OMΓΓ_ o TABLE I COMPOUNDS AND EEERACTIVE INDICES Compound -No. Rl -R2 - - * R3 - m 2 H -C2Ξ5 -C4H9-ΪI 1-5367 5 CE ■ 3O- allyl allyl 1.5380 • ϋTAMEES 7 Greenhouse Tests - Post-Baergence Post-Flood Application This example illustrates the herbicidal activity αf the six compounds listed above in the control of several broadleaf and grass weed species commonly associated with, rice crops. The effect αf the compounds on a rice crop grown adjacent to the weeds is also observed. S÷uπulations of flooded rice paddies were used for this test. The weed species were planted at intervals predetermined to provide a uniform degree of maturi¬ ty when the test compounds were applied. Both, direct seeded and trans¬ planted rice were used to represenc common growing tehcniques. The procedure was as follows: Plastic tubs measuring 11.1 inches (28.2 cm) in length, 6.7 inches (17-0 cm) in width, and 5-3 inches (13-5 cm) in depth were lined with plastic and filled to a depth to 2-3 inches (5.1-7-6 cm) with sandy loam soil containing 50 parts per million by weight (ppm) of cis-N-[(tri- chloromethyl)thio]-4-cyclohexene-l,2-dicarboxiπιide (a comπercial fungi¬ cide known as •■ Captan") and 17-17-17 (percentages of N-P2O5-K2O on a weight basis) fertilizer. The weed and rice species were then planted in each tub as follows: 1st day: Seeds of sprangletop (Leptochloa dubia) were planted in a single furrow. 5th day: Seeds of M-9 rice (Oryza sativa), sesbania (Sesbania exaltata), and yellow nutsedge (Cyperus esculentus), and cuttings of άayflower (C πiBlina cαnπunis) were planted in separate furrows. Additional seeds of M-9 rice were planted, in a separate tub. 12th day: Seeds of annual morning glory (Ipomoea purpurea) -and watergrass (Echinochloa crusgalll) were planted in further furrows in the tub containing the other weeds. 16th day: Rice plants grown in the separate tub were trans¬ planted into the tub containing all the other species. On the 20th day, the soil in each tub was flooded under 2-3 inches (5.1-7.6 cm) of water. The watergrass was in the two-leaf stage by this tine and was completely submerged fcy the water. The other weed species and the two rows of rice were all at the water line or slightly above. The test compounds were then added on the same day to the flood water from stock solutions made by dissolving 88 ng of test compound in 40 ml acetone containing 0.1% (by weight) of a polyoxyethylene sorbitan monolaurate surface-active agent. Aliquots of the appropriate amount of solution were used to provide an application rate rangi-rg from 0.125 to 4.0 pounds of active ingredient per acre (0.14 to 4.48 kilograms per hectare) in equivalent ' terms. The water level was then maintained in each tub or three weeks, at which time each species was evaluated for percent injury. The evaluation was a visual rating comparing the treated plants to untreated OMPI ™ plants grown under otherwise identical conditions in a separate tub. The rating ranged from 0 to 100$, with 0 representing no injury and lCO^ representing complete kill. The injury ra ing represented total plant injury due to all factors. The results are shown in Table II. OMPI TABLE II GREENHOUSE HERBICUE TEST RESULTS ■ _._ POST-EMERGENCE, POST-FLOOD APPLICATION Appli¬ Percent Injury Test cation Rice Compourid Rate ' Morning Ses- Nut- • Water- Sprangle- r&y- Direct Trans¬ No * . (lb/A) glory bania sedge grass too flower Seeded plante 1 0.125 0 0 0 0 0 0 0 0 0.25 0 0 0 50 0 0 0 0 0.5 90 0 20 100 100 0 20 20 1.0 90 10 85 100 100 0 35 35 2.0 90 20 85 100 100 50 50 50 4.0 100 75 95 100 100 • 95 75 75 2 0.125 0 0 0 0 0 0 0 0 0.25 0 0 0 20 95 0 0 0 0.5 100 0 0 95 95 0 10 0 1.0 100 0 25 100 100 0 20 10 2.0 100 75 95 100 100 95 20 • 20 4.0 100 100 100 100 100 100 85 85 3 0.125 0 0 0 0 0 0 0 0 0.25 0 0 0 25 50 0 0 0 0.5 0 0 0 95 50 0 0 0 1.0 0 0 0 100 95 0 0 0 2.0 0 0 0 100 100 0 0 0 4.0 0 0 85 100 100 * 0 40 0 4 0.125 0 0 0 0 0 0 0 0 0.25 0 0 0 40 95 0 0 0 0.5 100 0 0 100 95 0 0 . 0 1.0 100 0 60 100 100 0 0 0 2.0 100 0 60 100 100 0 0 0 4.0 100 0 60 100 100 20 10 - * 10 5 0.125 0 0 0 10 0 0 0 0 0.25 0 0 0 60 0 0 0 0 0.5 0 0 0 100 0 0 0 0 1.0 100 0 0 100 20 0 0 0 2.0 100 0 0 100 100 0 0 0 4.0 100 0 100 100 100 0 10 10 6 0.125 0 0 0 0 0 0 0 0 0.25 0 0 0 0 0 0 0 0 0.5 0 0 0 50 0 0 0 0 1.0 100 - 20 0 100 95 0 0 0 2.0 100 40 0 100 100 0. 10 20 4.0 100 40 20 100 100 0 20 20 EXAMPLE 8 Greenhouse Tests - Pre-Bπergence Surface Application In this series, the same six test αxπpounds were applied to dry soil a ter the planting of the weeds and rice, according to the following procedure: Silty clay soil containing neither fungicide nor fertilizer was placed in plastic tubs measuring 12.0 inches (30.5 cm) by 14 inches (35-6 cm) to a depth of 4 inches (10.2 cm). Seeds of watergrass, yellow nut- sedge, and -9 rice were planted in individual rows and the soil surface was watered lightly. Solutions of the test compounds in acetone contain¬ ing the surface-active agent, ranging from 150 to 450 mg of active ingre- dient per 50 ml of solution were then prepared. Appropriately selected solutions were sprayed over the soil surface by the use of a linear spray table at a spray rate corresponding to 80 gallons per acre (750 liters per hectare) to achieve application rates equivalent to 2 to 6 pounds of active ingredient per acre (2.2 to 6.7 kilograms per hectare). Two weeks later, an additional row of watergrass seeds was planted, and an additional two weeks later, a third row was planted. Ihese two late planting were done in order to test the residual activity of the test compounds. The tubs were watered regularly. Three weeks after the last watergrass seeds were planted, *' injury ratings of each plant species were taken as in Example 6. The results are shown in Table III. TABLE III GREENHOUSE HERBICIDE TESE RESULTS — PRE-EMERGENCE SURFACE APPLICATION "Percent Injury • Test Application Watergrass — • Seeding Date Compound Rate Day of 2 4 No. ' (lb/A) Nutsed,ge Application Weeks Veeks Rice 1 2 10 98 0 0 0 4 20 100 0 0 0 6 40 100 0 0 0 2 2 0 50 0 . 0 0 4 20 50 0 " 0 10 6 20 100 0 0 20 3 2 0 0 0 0 0 4 0 50 • 0 0 0 6 0 80 0 0 0 4 2 0 0 0 0 0 4 10 80 0 0 0 6 10 90 25 0 0 5 2 0 50 0 0 0 4 10 90 20 10 20 6 20 ICO 90 95 25 6 2 0 50 ' 0 0 0 4 ID 50 10 0 15 6 10 50 20 0 25 EXAMPLE 9 Outdoor Tests — Post-ESmergence, Post-Flood Application In this series, four of the compounds were tested in outdoor tubs following a procedure similar to that described in Example 7 above. This series covers various stages in the growth of both rice and water¬ grass. Plastic tubs which were 16.0 inches (40.6 cm) in diameter and 8.5 inches (21.6 cm) deep were filled to a depth of 3-0 inches (7.6 cm) with sandy loam soil containing 50 ppm each of the same fungicide and fertilizer used in the tests in Example 7. The seeding plan was as ollows: 1st day: Seeds of yellow πutsedge and sprangle top were planted. 5th day: Seeds of red rice (a weed species) and M-9 rice were planted. Additional M-9 rice seeds were planted in a sep¬ arate tub for later transplanting. 7th day: Dayflower cuttings were planted. 12th day: Seeds of watergrass and M-9 rice were planted. 16th day: Seeds of sesbania, watergrass, and M-9 rice were planted. 19th day: Seeds of watergrass and M-9 rice were planted. 25th day: The separately grown rice plants were transplanted to the main tub. On the 27th day, the tubs were flooded to achieve a water depth of 5-0 inches (12.7 cm), and aliquots of test compound solutions in ace¬ tone containing the surface-active agent were added to the flood water to provide application rates equivalent to 0.5 to 4.0 pounds of active in¬ gredient per acre (0.56 to 4.48 kilograπs per hectare) (18.4 g per tub is equivalent to 1 pound per acre). At this point, the dayflower plants were about 90 submerged, the sesbania were 2 inches (5-1 cm) tall with primary leaves, secondary growth beginning to appear, the sprangletop showed sporadic growth averaging 6 inches (15.2 cm) in height, the red rice plants were 7 to 8 inches (17.8-20.3 cm) tall, and the nutsedge were just above the water level. Due to cold weather, the sprangletop in several of the tubs failed to germinate. The watergrass in its several separate planting ranged from the two-leaf stage (1-2 inches or 2.5-5«l cm tall) to the four-leaf stage (7-9 inches or 17.8-22.9 cm tall). The M-9 rice ranged from the one-leaf stage (1-2 inches or 2.5-5*1 cm tall) to the three-leaf stage (5-7 inches or 12.7-17.8 cm tall). The results are shown in Table 17. TABLE IV OUTDOOR HERBICHE TEST RESULTS — POST-MERC2ΞNCE, POST-FLOOD APPLICATION Appli- Percent Injury cation Watergrass M-9 Rice: Days Rate Sprangle Red Ses- Nut- Day- Days Trans- (Ib/A) top Rice bania sedge flower 15 11 T " 18 15 H 8 plante Test Compound No. 2: 0.5 0 0 0 0 0 0100 50 0 0 0 50 0 1.0 100 0 0 0 — 20100 95 0 0 0 50 0 2.0 10 100 10 90 100100 — 0. 0 50 90 0 4.0 20 100 90 100 100100 — 20 20 90 — 0 Test Coπ-pound No. 3: 0.5 0 0 0 0 0 0 0 — 0 0 0 0 0 1.0 100 0 0 0 0 50 — — 0 0 0 0 0 2.0 100 0 100 0 95 90100 — 0 0 0 0 0 4.0 100 0 100 20 100 90100 — 0 0 0 0 0 Test Coπp->und No. 4: 0.5 o ■ 0 0 0 0 0100 — θ 0 0 0 0 1.0 0 0 0 0 0 50100 — 0 0 0 0 0 2.0 100 0 0 0 0 85100 — 0 0 0 0 0 4.0 100 0 0 20 95 95100100 0 0 0 0 0 Test Coπ-pound No. 5: 0.5 — 0 0 0 σ 0 0 — 0 0 0 0 0 1.0 — 0 0 0 0 10100 — 0 0 0 0 0 2.0 — 0 0 0 90 20 90 90 0 0 0 0 0 4.0 — 100 90 95 90 100 — —— 0 0 0 0 0 EXAMPLE 10 Outdoor Tests — Post-Emergence, Post-Flood Application This series is similar to that of Example 9, except that all six test con-pounds shown in Table I were tested. The seeding plan was as follows: 1st day: Yellow nutsedge seeds were planted. 2nd day: Dayflower cuttings were planted. 14th day: Sesbania seeds were planted. 19th day: Red rice and M-9 rice seeds were planted. Addition¬ al red rice seeds were planted in a separate tub for later transplanting. 22nd day: Watergrass and M-9 rice seeds were planted. 24th day: Watergrass seeds Vere planted. 26th day: Watergrass seeds were planted. 28th day: Watergrass seeds were planted. 33rd day: The separately grown rice plants were transplanted to the main tub. Flooding and treatment with the test compounds were done en the 37th day .and injury ratings were taken four weeks later. The results are shown in Table V. OMPI TABLE V OUTDOOR HERBICIDE 1_ESr RESULTS — POST-EMERGENCE, POST-FLOOD APPLICATION Test Appli¬ Percent Injury Com¬ cation Watergrass M-9 Rice : Days pound Rate Red Ses- Nut- Day- Days Trans- No. (lb/A) Rice bania sedge flowe- -15 13 11 9 18 15 olanted 1 1.0 0 0 ' 0 0 75 75 0 0 0 0 0 1.0 0 0 0 0 40 60 0 0 0 0 0 2.0 0 0 0 0 50 50100100 0 0 0 2.0 0 0 0 0 90 90.100100 0 0 0 3.0 0 90 0 90 75 75100100 0 0 0 3.0 0 95 0 90 80 95100100 0 0 0 4.0 0 95 0 90 100100100100 15 15 0 4.0 0 95 0 90 100100100100 20 20 0 2 1.0 0 0 0 0 0 0 0 0 0 0 0 1.0 0 0 0 0 0 75 0 0 0 0 0 2.0 0 0 0 0 20 75100100 " 0 0 0 2.0 0 0 0 0 75100100100 0 0 0 3.0 0 0 0 0 100100100100 * o 0 0 3.0 0 0 0 0 95100100100 0 0 0 4.0 10 0 0 0 100100100100 5 5 10 4.0 10 0 0 0 95100100100 10 10 10 •' 6.0 10 0 0 0 100100100100 10 10 10 6.0 10 0 0 0 100100100100 10 10 "' 10 3 1.0 0 0 0 0 0 90100100 0 0 0 1.0 0 0 0 0 0 0100100 0 0 0 2.0 0 0 0 0 20 90100100 0 0 0 2.0 0 0 0 0 0 90100100 0 0 0 3.0 0 0 0 0 98100100100 0 0 0 3.0 0 0 0 0 75100100100 0 0 0 4.0 10 -o 0 0 100100100100 10 10 10 4.0 10 0 0 0 100100100100 10 10 10 6.0 10 0 0 10 100100100100 10 10 10 6.0 10 100 0 10 100100100100 10 10 10 OMPI TABLE Y (Continued) Test Appli¬ ■ ' ' Percent Inury ... . Com¬ cation Watergrass M-y Rice : Days pound Rate Red Ses- Nut¬ Day- Days - Trans¬ No. (Ϊb/A) Rice bania sedgei flower is ιι- y 18 15 planted 4 1.0 0 0 0 0 0 0100100 0 0 0 1.0 0 0 0 0 0 0100100 0 0 0 2.0 0 0 0 0 20 75100100 0 0 0 2.0 0 0 0 0 0 75 0 0 0 0 0 3-0 0 0 0 0 95100-100100. 0 0 0 3-0 0 0 0 0 100100100100 0 0 0 4.0 0 0 0 10 100100100100 10 10 10 4.0 10 0 0 10 100100100100 20 20 20 6.0 10 50 0 90 100100100100 20 20 20 6.0 10 100 0 90 100100100100 25 50 25 5 1.0 . 0 0 0 0 0 0100100 0 0 — 1.0 0 0 0 0 0 75100100 0 0 2.0 0 0 0 0 0 90100100 0 0 — 2.0 • 0 • 0 0 0 20 50100100 0 0 3-0 0 0 0 0 75100100100 0 0 — 3.0 0 0 0 0 75 75100100 0 0 4.0 0 0 0 0 90 90100100 0 0 4-0 0 0 0 0 100100100100 0 0 •— 6.0 0 0 0 0 95 95100100 0 0 6.0 0 0 0 0 95 95100100 0 0 6 1.0 0 0 0 0 75 0100100 0 0 0 2.0 0 75 10 0 85100100100 0 0 0 3.0 0 100 10 100 95100100100 0 0 0 3-0 0 100 10 100 75100100100 0 0 0 4.0 0 100 10 100 98100100100 0 0 0 4-0 0 100 10 100 100100100100 0 0 0 6.0 0 100 10 75 100100100100 0 0 0 6.0 0 100 10 ICO 100100100100 0 0 0 Oϊ.frl " EXAMPLE 11 Greenhouse Tests - Post-Einergence, Post-Flood Application This series of tests was run on watergrass only, focusing on the residual activity of the test compounds in water after one month. Planting tubs identical to those used in Example 7 were planted with watergrass seeds. After one week, the tubs were flooded with treated water taken from the outdoor tubs of Example 9. Three weeks later, injury ratings were taken. The results are shown in Table VI. TABIE VI GREENHOUSE TEST RESULTS — POST-EMERGENCE APPLICATION USING PRE-TREAΕD FLOOD WATER (Watergrass only) Application Percent Injury Rate (lb/A) COMPOUND NO: 1 2 3 4 3 6 1.0 0 0 0 0 0 0 1.0 20 0 0 0 0 2.0 75 0 0 0 0 0 2.0 75 0 0 0 0 3.0 90 0 0 0 0 0 3.0 60 0 0 0 0 0 4.0 98 0 0 0 0 10 4.0 100 0 0 0 0 10 6.0 — 0 10 10 0 10 6.0 0 10 10 0 10 METHODS OF APPLICATION The coπ ounds of the present invention are useful in control¬ ling the growth of undesirable vegetation by preemergence or post- emergence application to the locus where control is desired. The compounds are generally embodied in formulations suitable for convenient application, containing additional ingredients or diluent carriers to aid in the dispersal of the con-positions. Examples of such ingredients or carriers are water, organic solvents, granules, surface active agents, OM?I water-oil emulsions, wetting agents, dispersing agents, and emulsifying agents. The formulated compositions generally take the form of emulsifi- able concentrates, granules, or microcapsules. A. MUISLPIABLE CONC TRATES Emulsifiable concentrates are solutions in which the active material and an emulsifying agent are dissolved in a non-water-miscible solvent. Prior to use, the concentrate is diluted with water to form a suspended emulsion of solvent droplets. Typical solvents for use in emulsifiable concentrates include weed oils, chlorinated hydrocarbons, and non-water-miscible ethers, esters, and ketones. Typical emulsifying agents are anionic or nonionic surfactants, or mixtures of the two. Examples include long-chain mercaptan polyethoxy alcohols, alkylaryl polyethoxy alcohols, sorbitan fatty acid esters, polyoxyethylene ethers with sorbitan fatly acid esters, polyoxyethylene glycol esters with fatty or rosin acids, fatty aliylol amide condensates, calcium and amine salts of fatty alcohol sulfates, oil soluble petroleum sulfonates, or preferably mixtures of these emulsifying agents. Such emulsifying agents usually comprise about 1 to 10 weight percent αf the total composition. Iζypical emulsifiable concentrates contain about 15 to 50 weight percent active material, about 40 to 82 weight percent solvent, and about 1 to 10 weight percent emulsifier. Other additives such as spreading agents and stickers can also be included. B. GRANULES Granules are physically stable, particulate compositions in which the active ingredient adheres to or is distributed throughout a basic matrix of a coherent, inert carrier with macroscopic dimensions. A typical particle is about 1 to 2 millimeters in diameter. Surfactants are often present to aid in the leaching of the active ingredient from the granule to the surrounding medium. The carrier is preferably of mineral origin, and generally falls within one of two types. The first are porous, absorptive, pre¬ formed granules, such as attapulgite or heat expanded vermiculite. A solution of the active agent is sprayed on the granule at concentrations of up to 25 weight percent of the total weight. The second are powdered materials to which the active ingredients are added prior to being formed into granules. These materials include kaolin clays, hydrated attapul¬ gite, or bentonite clays in the form of sodium, calcium, or magnesium bentonites. Water-soluble salts may also be present to help the granules disintegrate in water. These ingredients are blended with the active components, then granulated or pelleted, followed by drying. In the resulting composition, the active component is distributed uniformly throughout the mass. Granules can be made with as much as 25 to 30 weight percent active component, but more frequently a concentration of about 10 weight percent is desired for optimum distribution. Granule compositions are most useful in a size range of 15-30 mesh. The surfactant is generally a common wetting agent of anionic or nonionic character. The most suitable wetting agents depend upon the type of granule used. When preformed granules are sprayed with active material in liquid form, the most suitable wetting agents are nonionic, liquid wetters miscible with the solvent. These are compounds generally known as e ulsifiers, and comprise alkylaryl polyether alcohols, alkyl polyether alcohols, polyoxyethylene sorbitan fatty acid esters, poly¬ ethylene glycol esters with fatly or rosin acids, fatty alkylol amide condensates, oil solution petroleum or vegetable oil sulfonates, or mix¬ tures of these. Such agents usually comprise up to about 5 weight per¬ cent of the total composition. When the active ingredient is first mixed with a powdered car¬ rier and subsequently granulated, liquid nonionic wetters can still be used, but it is usually preferable to incorporate at the mixing stage a solid, powdered anionic wetting agent comprising up to about 2.0 weight percent of the total composition. Typical granules comprise about 5 to 30 percent by weight active material, about 0 to 5 weight percent wetting agent, arri. about 65 to 95 weight percent carrier. C. MICROCAPSULES Microcapsules are fully enclosed droplets or granules in which the active material is enclosed in an inert porous membrane which allows the enclosed material to escape to the surrounding medium at controlled rates. Encapsulated droplets are -typically about 1 to 50 microns in diameter. The enclosed liquid typically constitutes about 50 to 95 of the weight of the capsule, and may contain a_ small amount of solvent in addition to the active materials. Encapsulated granules are characterized by porous membranes sealing the openings of the granule carrier pores, trapping the liquid containing the active components inside for controlled release. A typi¬ cal granule size ranges frcm 1 millimeter to 1 centimeter in diameter. Granules formed by extrusion, agglomeration, or prilling are useful in the present invention as well as materials in their naturally occurring form. Examples of such carriers are vermiculite, sintered clay granules, kaolin, attapulgite clay, sawdust, and granular carbon. Useful encapsulating materials include natural and synthetic rubbers, cellulosic materials, styrene-butadiene copolymers, polyacrylo- "' nitriles, polyacrylates, polyesters, polyamides, polyurethanes, and starch xanthates. D. IN GENERAL In general, any conventional method of application can be used. The locus of application can be soil, seeds, seedling, or the actual plants, as well as flooded fields. Liquid compositions can be applied by the use of boom or hand sprayers. Liquid or solid compositions can be applied from airplanes ' . The compositions can also be added .to irrigation water so that they will accompany the water as it penetrates the soil, and also to flood water in rice cultivation. The amount of active ingredient required for herbicidal effectiveness depends upon the nature of the seeds or plants to be controlled and the prevailing conditions. Usually, herbicidal effects are obtained with an application rate of about 0.01 to ' about 50 pounds per acre, preferably about 0.1 to about 25- It. will be readily apparent to one skilled in the art that compounds -exhibiting lower herbicidal activity will require a higher dosage than more active compounds for the same degree of control.

Claims: WHAT IS CLAIMED IS: 1. A compound having the formula in which Rl is selected from the group consisting of hydrogen and methoxy, 5 R 2 is selected from the group consisting of methyl, ethyl, and allyl, and R5 is selected from the group consisting of straight-chain C3-C6 alkyl optionally substituted with one or two methyl groups, and allyl. 10 2. A compound according to Clai 1 in which Rl is selected from the group consisting of hydrogen and methoxy,. R 2 is selected from the group consisting of methyl, ethyl, and allyl, 'and 15 3 is selected from the group consisting of n-butyl, n-pentyl, 1,2-dimethylpropyl, and allyl. 3- A compound according to Claim 1 in which R is hydrogen, R 2 is ethyl, and R3 is 1,2-dimethylpropyl. 4. A compound according to Claim 1 . in which Rl is hydrogen, 20 R 2 is ethyl, and R5 is n-butyl. 5. A compound according to Claim 1 in which R.1 is hydrogen, t. . R 2 is methyl, and R5 is n-pentyl. 6. A compound according to Claim 1 in walch R.1 is hydrogen, R 2 is ethyl, and 5 is n-pentyl. 25 7. A compound according to Claim 1 in which R is methoxy, R 2 is allyl, and R-5 is .allyl. 8. A compound according to Claim 1 in which R is hydrogen, R 2 is methyl, and R3 is n-butyl. 9. An herbicidal coπ-position comprising an herbicidally e ective amount of a coπ-pound having the formula in which Rl is selected from the group consisting of hydrogen and methoxy, R 2 is selected from the group consisting of methyl, ethyl, and allyl, and R3 is selected rom the group consisting of C3-C5 alkyl optionally substituted with one or two methyl groups, and allyl, and an inert carrier. 10. A composition according to Claim 9 in which R*-- is selected from the group consisting of hydrogen and methoxy, R 2 is selected from the group consisting of methyl, ethyl, and allyl, and R3 is selected from the group consisting of n-butyl, n-pentyl, 1,2-dimethylpropyl, and allyl. 11. A composition according to Claim 9 in which Rl is hydrogen, R 2 is ethyl, and R3 is 1,2-dimethylpropyl. 12. A composition according to Claim 9 in which R.1 is hydrogen, R 2 is ethyl, and R3 is n-butyl. 13- A composition according to Claim 9 in which Rl is hydrogen, R 2 is methyl, and R3 is n-pentyl. 14. A ccπposition according to Claim 9 in which Rl is hydrogen, R 2 is ethyl, and R3 is n-pentyl. OMH 15- A composition according to Claim 9 in which Rl is methoxy, R 2 is allyl, and R3 is allyl. 16. A composition according to Claim 9 in which Rl is hydrogen, R 2 is methyl, and R5 is n-butyl. 17. A method of controlling undesirable vegetation in rice crops comprising applying to the locus where control is desired an herbicidal composition comprising an herbicidally effective amount of a compound having the formula in which Rl is selected from the group consisting of hydrogen and methoxy, R 2 is selected from the group consisting of methyl, ethyl, and allyl, and R5 is selected from the group consisting of strai^it-chain C 3~C6 alkyl optionally substituted with one or two methyl groups, and allyl, and an inert diluent carrier. 18. A method according to Claim 17 in which Rl is selected from the group consisting of hydrogen and " methoxy, R 2 is selected from the group consisting of methyl, ethyl, and allyl, and R5 is selected from the group consisting of n-butyl, n-pentyl, 1,2-dimethylpropyl, and allyl. 19. A method according to Claim 17 in which Rl is hydrogen, R 2 is ethyl, and 5 is ' 1,2-dimethylpropyl. 20. A method according to Claim 17 in which Rl is hydrogen, R 2 is ethyl, and R3 is n-butyl. 21. A method according to Claim 17 in which Rl is hydrogen, R 2 is methyl, and R3 is n-pentyl. 22. A method according to Claim 17 in which Rl is hydrogen, R 2 is ethyl, and 5 is n-pentyl. 23« A method according to Claim 17 in which R.1 is methoxy, R 2 is allyl, and R3 is allyl. 24« A method according to Claim 17 in which Rl is hydrogen, R 2 is methyl, and 5 is n-butyl. OMP

Inventors: BUREN LAWRENCE LAMONT, JAMES DONALD RICHARD, RANDOLPH BARNEY JULIUS, TEACH EUGENE GORDON, TILLES HARRY, WALKER FRANCIS HARRY, BUREN, LAWRENCE, LAMONT, JAMES, DONALD, RICHARD, RANDOLPH, BARNEY, JULIUS, TEACH, EUGENE, GORDON, TILLES, HARRY, WALKER, FRANCIS, HARRY
Applicants: STAUFFER CHEMICAL CO, STAUFFER CHEMICAL COMPANY
Application year: 1982
Main classification: C07C155
IPC codes: A01N47