Herbicidal pyridazinone derivatives

Abstract

The present invention relates to herbicidal benzyloxy-substituted phenyl-diones and benzyloxy substituted phenyl-dioxo-thiazinone derivatives of formula (I), as well as to processes and intermediates used for the preparation of such derivatives. The invention further extends to herbicidal compositions comprising such derivatives, as well as to the use of such compounds and compositions in controlling undesirable plant growth: in particular the use in controlling weeds, such as broad-leaved dicotyledonous weeds, in crops of useful plants.

Claims

1. A compound of formula (I) ##STR00020## or a salt or N-oxide thereof, R.sup.1 is selected from the group consisting of C.sub.1-C.sub.4 alkyl, C.sub.3-C.sub.6cycloalkyl, C.sub.3-C.sub.6alkoxy, C.sub.1-C.sub.2 alkoxy-C.sub.1-C.sub.2 alkyl, C.sub.2-C.sub.4 alkenyl, C.sub.1-C.sub.4 haloalkyl, cyano-C.sub.1-C.sub.4alkyl, C.sub.2-C.sub.4 haloalkenyl, C.sub.2-C.sub.4 alkynyl and C.sub.2-C.sub.4 haloalkynyl; R.sup.2 is selected from the group consisting of hydrogen, halogen, cyano, C.sub.1-C.sub.6alkyl, C.sub.1-C.sub.6haloalkyl, C.sub.1-C.sub.6haloalkoxy, C.sub.1-C.sub.3haloalkoxy-C.sub.1-C.sub.3alkyl-, C.sub.1-C.sub.6alkoxy, C.sub.1-C.sub.3alkoxy-C.sub.1-C.sub.3alkyl, C.sub.1-C.sub.3alkoxy-C.sub.1-C.sub.3alkoxy-C.sub.1-C.sub.3alkyl-, C.sub.3-C.sub.6cycloalkyl, C.sub.2-C.sub.6 alkenyl, C.sub.2-C.sub.6 haloalkenyl, C.sub.2-C.sub.6 alkynyl, C.sub.1-C.sub.6hydroxyalkyl-, C.sub.1-C.sub.6alkylcarbonyl-, C.sub.1-C.sub.6alkyl-S(O).sub.m, amino, C.sub.1-C.sub.6alkylamino, C.sub.1-C.sub.6dialkylamino, C(C.sub.1-C.sub.3alkyl)=NOC.sub.1-C.sub.3alkyl and C.sub.2-C.sub.6 haloalkynyl; G is hydrogen, or C(O)R.sup.3; X and Y are each independently hydrogen, C.sub.1-C.sub.3 alkyl, C.sub.1-C.sub.3 alkoxy, C.sub.1-C.sub.3haloalkyl, C.sub.1-C.sub.3haloalkoxy, or halogen; Z is C.sub.1-C.sub.3 alkyl, C.sub.1-C.sub.3 alkoxy, C.sub.1-C.sub.3haloalkyl, C.sub.1-C.sub.3haloalkoxy, or halogen; m is an integer of 0, 1, or 2; n is an integer of 0, 1, 2, 3, 4, or 5; R.sup.3 is selected from the group consisting of C.sub.1-C.sub.6alkyl, C.sub.1-C.sub.6alkoxy, C.sub.1-C.sub.6alkenyl, C.sub.1-C.sub.6alkynyl, C.sub.1-C.sub.6alkyl-S, NR.sup.4R.sup.5 and phenyl optionally substituted by one or more R.sup.6; R.sup.4 and R.sup.5 are independently selected from the group consisting of C.sub.1-C.sub.6 alkyl and C.sub.1-C.sub.6 alkoxy, or R.sup.4 and R.sup.5 together can form a morpholinyl ring; and, R.sup.6 is selected from the group consisting of halogen, cyano, nitro, C.sub.1-C.sub.3alkyl, C.sub.1-C.sub.3haloalkyl, C.sub.1-C.sub.3alkoxy and C.sub.1-C.sub.3haloalkoxy, wherein the compound of formula (I) can be in the following tautomeric forms when R.sup.2 is hydrogen and G is hydrogen: ##STR00021##

2. The compound according to claim 1, wherein G is hydrogen or C(O)R.sup.3 wherein R.sup.3 is isopropyl, t-butyl, methyl, ethyl, propargyl, methoxy, ethoxy, or tert-butoxy.

3. The compound of claim 1, wherein X is hydrogen, halogen, or C.sub.1haloalkyl.

4. The compound of claim 1, wherein Y is hydrogen, C.sub.1-C.sub.3 alkyl, C.sub.1-C.sub.3haloalkyl, or halogen.

5. The compound of claim 1, wherein X is ortho with respect to the pyrdazinone/pyridazine-dione moiety.

6. The compound of claim 1, wherein Y is ortho with respect to the benzyloxy moiety.

7. The compound of claim 1, wherein R.sup.1 is methyl, ethyl, n-propyl, cyclopropyl, propargyl, or C.sub.1haloalkyl.

8. The compound of claim 1, wherein R.sup.2 is selected from the group consisting of hydrogen, C.sub.1-C.sub.6alkyl, C.sub.1-C.sub.6haloalkyl, C.sub.1-C.sub.6alkoxy, C.sub.1-C.sub.3alkoxy-C.sub.1-C.sub.3alkyl, C.sub.3-C.sub.6cycloalkyl, C.sub.2-C.sub.6 alkenyl, C.sub.2-C.sub.6 haloalkenyl, C.sub.2-C.sub.6 alkynyl and C.sub.2-C.sub.6 haloalkynyl.

9. The compound of claim 1, wherein R.sup.2 is selected from the group consisting of, methyl, ethyl, cyclopropyl, trifluoromethyl and methoxymethyl.

10. The compound of claim 1, wherein R.sup.2 is cylcopropyl or methyl.

11. The compound of claim 1, wherein each Z is independently selected from halogen, methyl, methoxy, and trifluoromethyl.

12. A herbicidal composition comprising a herbicidal compound according to claim 1 and an agriculturally acceptable formulation adjuvant.

13. The herbicidal composition according to claim 12, further comprising at least one additional pesticide.

14. A method of controlling unwanted plant growth, the method comprising applying a compound of formula (I) as defined in claim 1 to the unwanted plants or to the locus thereof.

Description

PREPARATION EXAMPLES

Example 1 Preparation of 4-(2-benzyloxy-3,6-dichloro-phenyl)-2,6-dimethyl-pyridazine-3,5-dione

(1) ##STR00013##

1.1 2-Allyl-3,6-dichloro-phenol

(2) A mixture of 2-allyloxy-1,4-dichloro-benzene (1.0 g, 4.9 mmol, 1.0 eq.) and DMF (0.1 mL) was heated at an external temperature of 220 C. for 1 hour. The mixture was allowed to cool to room temperature and was concentrated in vacuo to provide 2-allyl-3,6-dichloro-phenol as a brown oil (0.99 g, 99%).

(3) ##STR00014##

(4) .sup.1H NMR (400 MHz, CDCl.sub.3): .sub.H: 7.18-7.08 (1H, m) 6.95-6.85 (1H, m) 6.02-5.84 (1H, m) 5.71 (1H, s) 5.14-4.99 (2H, m) 3.59 (2H, dt).

1.2 2-Allyl-3-benzyloxy-1,4-dichloro-benzene

(5) Benzyl bromide (3.2 mL, 27 mmol, 1.1 eq.) was added to a suspension of 2-allyl-3,6-dichloro-phenol (5.0 g, 25 mmol, 1.0 eq.) and potassium carbonate (3.7 g, 27 mmol, 1.1 eq.) in acetone (49 mL) and the mixture was heated at reflux for 6 hours. The mixture was allowed to cool to room temperature and was filtered. The filtrate was concentrated in vacuo and the crude product was purified by flash column chromatography to provide 2-allyl-3-benzyloxy-1,4-dichloro-benzene (4.031 g, 56%) as a colourless oil.

(6) ##STR00015##

(7) .sup.1H NMR (400 MHz, CDCl.sub.3): .sub.H: 7.54-7.49 (2H, m), 7.45-7.35 (3H, m), 7.27-7.24 (1H, m), 7.15 (1H, d), 6.01-5.90 (1H, m), 5.10-4.97 (4H, m), 3.59 (2H, dt).

1.3 2-(2-Benzyloxy-3,6-dichloro-phenyl)acetic acid

(8) A solution of 2-allyl-3-benzyloxy-1,4-dichloro-benzene (38.1 g, 130 mmol, 1.00 eq.) in dichloromethane (650 mL) in a 3-necked flask was cooled to 78 C. One side neck was connected to a Dreshel bottle containing an aqueous solution of KI (100 mL, 15% w/w). Ozone was bubbled through the solution until 2-allyl-3-benzyloxy-1,4-dichloro-benzene had been fully consumed (4 hours). Air was bubbled through the solution for 10 minutes to remove excess ozone. The bubbling of gas through the solution was stopped and dimethyl sulfide (95.4 mL, 1300 mmol, 10.0 eq.) was added. The mixture was allowed to warm to room temperature and was stirred for 12 hours. The mixture was washed with brine (2200 mL) and the organic extracts were passed through a hydrophobic frit. The mixture was concentrated in vacuo to provide a yellow oil (43 g). The residue was dissolved in a mixture of in tert-butanol (260 mL) and water (130 mL) then cooled to 0 C. 2-methylbut-2-ene (135 mL, 1300 mmol, 10.0 eq.), sodium dihydrogen phosphate (62.4 g, 520 mmol, 4.00 eq.) and sodium chlorite (44.1 g, 390 mmol, 3.00 eq.) were added. The mixture was stirred for 2 hours then diluted with brine (300 mL) and 2.0M hydrochloric acid (300 mL). The mixture was extracted with EtOAc (3200 mL). The combined organic extracts were washed with a saturated aqueous solution of sodium metabisulfite (200 mL) then passed through a hydrophobic frit and concentrated in vacuo to provide a pale yellow solid (41.4 g). The residue was suspended in H.sub.2O (200 mL) and an aqueous solution of NaOH (30 mL, 2.0 M) was added resulting in a clear solution. The mixture was washed with Et.sub.2O (100 mL) and the aqueous layer was acidified by addition of concentrated HCl (20 mL) resulting in the formation of a precipitate. The mixture was filtered and the filtrand was dried in vacuo to provide 2-(2-benzyloxy-3,6-dichloro-phenyl)acetic acid (29.2 g, 72%) as a white solid.

(9) ##STR00016##

(10) .sup.1H NMR (400 MHz, CDCl.sub.3): .sub.H: 7.48-7.44 (2H, m), 7.42-7.31 (4H, m), 7.17 (1H, d), 5.04 (2H, s), 3.85 (2H, s).

1.4 ethyl (2E/Z)-2-(methylhydrazono)propanoate

(11) A 3-necked 500 mL flask equipped with a stirrer bar, dropping funnel and thermometer was placed under N.sub.2 atmosphere. Chloroform (60 mL), ethyl 2-oxopropanoate (12.9 g, 111 mmol) and magnesium sulfate (13.3 g, 111 mmol) were charged to the vessel with stirring. The resulting slurry was cooled to 0 C. (ice bath). The dropping funnel was then charged with chloroform (20 mL) and methylhydrazine (5.00 g, 109 mmol). The methylhydrazine solution was then added dropwise to the stirred reaction mixture, setting the rate of addition to maintain the temperature <10 C. After the addition was complete, the reaction was warmed to ambient temperature and then stirred for a further 16 h.

(12) The reaction was filtered, washing with chloroform. The filtrate was concentrated under reduced pressure to give the desired hydrazone ethyl-2-(methylhydrazono)propanoate (15.1 g, 105 mmol, 96.5% Yield), a yellow oil, as a mixture of E/Z isomers.

(13) ##STR00017##

(14) .sup.1H NMR data for major isomer: (400 MHz, CDCl.sub.3): .sub.H: 5.58 (1H, brs), 4.30 (2H, q, 3.24 (3H, s), 1.92 (3H, s), 1.34 (3H, t).

1.5 ethyl 2-[[2-(2-benzyloxy-3,6-dichloro-phenyl)acetyl]-methyl-hydrazono] propanoate

(15) 2-(2-benzyloxy-3,6-dichloro-phenyl)acetic acid (1.32 mmol, 0.41 g) was dissolved in dichloromethane (10 mL) under N.sub.2 with stirring. Oxalyl chloride (3.95 mmol, 0.50 g, 0.34 mL) was added. After 2 min, N,N-dimethylformamide (0.13 mmol, 0.01 mL) was added dropwise. Effervescence was observed. After 1 h stirring at ambient temperature, LC/MS analysis of an aliquot quenched into MeOH showed complete conversion of acid starting material to the methyl ester (evidencing acyl chloride formation).

(16) The reaction mixture was concentrated in vacuo to afford an orange gum.

(17) The crude acid chloride was then redissolved in dichloromethane (10 mL) under N.sub.2 atmosphere and cooled to 0 C. Ethyl 2-(methylhydrazono)propanoate (1.34 mmol, 0.194 g) was added with stirring. Triethylamine (2.64 mmol, 0.37 mL) in dichloromethane (0.5 mL) was added dropwise over 10 min. The reaction mixture was stirred at 0 C. for a further 15 min, before being warmed to ambient temperature and continued a further 4 h.

(18) The solvent was evaporated in vacuo and the residue redissolved in ethyl acetate (30 mL). Organics were washed with dilute aq. HCl solution (210 mL), saturated aq. NaHCO.sub.3 solution (210 mL) and brine (210 mL), before being passed through a phase separator cartridge and concentrated in vacuo.

(19) Flash column chromatography (silica, eluant a 0-5% ethyl acetate in hexane gradient) afforded the desired product ethyl 2-[[2-(2-benzyloxy-3,6-dichloro-phenyl)acetyl]-methyl-hydrazono]propanoate (0.21 g, 36.5%) as a yellow gum.

(20) ##STR00018##

(21) .sup.1H NMR (400 MHz, CDCl.sub.3): .sub.H: 7.49-7.23 (6H, m), 7.18-7.11 (1H, m), 5.05-4.97 (2H, m), 4.31 (2H, q), 4.20 (2H, s), 3.31 (3H, s), 2.21 (3H, s), 1.34 (3H, t).

1.6 4-(2-benzyloxy-3,6-dichloro-phenyl)-2,6-dimethyl-pyridazine-3,5-dione

(22) A microwave vial was charged with ethyl 2-[[2-(2-benzyloxy-3,6-dichloro-phenyl)acetyl]-methyl-hydrazono]propanoate (0.46 mmol, 0.20 g), acetonitrile (4 mL) and 1,8-Diazabicyclo[5.4.0]undec-7-ene (0.98 mmol, 0.15 g, 0.15 mL). The mixture was heated under microwave irradiation at 125 C. for 50 min before LC/MS analysis showed complete reaction. The reaction mixture was diluted with ethyl acetate (20 mL) and water (10 mL) and acidified to pH 4-5 with dilute hydrochloric acid. The organics were separated and further washed with saturated aqueous ammonium chloride solution (210 mL) then brine (10 mL). The organics were then passed through a phase separator cartridge and concentrated in vacuo to afford a crude yellow gum. Flash column chromatography (silica, eluant 0-25% ethyl acetate in hexane gradient) afforded the desired product 4-(2-benzyloxy-3,6-dichloro-phenyl)-2,6-dimethyl-pyridazine-3,5-dione (0.11 g, 61%) as a pale yellow gum.

(23) ##STR00019##

(24) .sup.1H NMR (400 MHz, CDCl.sub.3): .sub.H: 2.22 (3H, s), 3.66 (3H, s), 4.70 (1H, d), 5.08 (1H, d), 7.13-7.17 (2H, m), 7.24-7.30 (4H, m), 7.41 (1H, d).

BIOLOGICAL EXAMPLES

(25) B1 Post-Emergence Efficacy

(26) Seeds of a variety of test species are sown in standard soil in pots:Solanum nigrum (SOLNI), Amaranthus retoflexus (AMARE), Setaria faberi (SETFA), Alopecurus myosuroides (ALOMY), Echinochloa crus-galli (ECHCG), Ipomoea hederacea (IPOHE), Lolium perenne (LOLPE). After 8 days cultivation (post-emergence) under controlled conditions in a glasshouse (at 24/16 C., day/night; 14 hours light; 65% humidity), the plants are sprayed with an aqueous spray solution derived from the formulation of the technical active ingredient in acetone/water (50:50) solution containing 0.5% Tween 20 (polyoxyethelyene sorbitan monolaurate, CAS RN 9005-64-5). Compounds are applied at 1000 g/ha. The test plants are then grown in a glasshouse under controlled conditions in a glasshouse (at 24/16 C., day/night; 14 hours light; 65% humidity) and watered twice daily. After 13 days, the test is evaluated for the percentage damage caused to the plant. The biological activities are assessed on a five point scale (5=80-100%; 4=60-79%; 3=40-59%; 2=20-39%; 1=0-19%). A blank value in the table is indicative that the compound was not tested on that species.

(27) TABLE-US-00002 TABLE 2 Control of weed species by compounds of formula (I) after post-emergence application at a rate of 1000 g/Ha Compound LOLPE SOLNI AMARE SETFA ALOMY ECHCG IPOHE 1.001 5 5 5 4 5 5 1.002 1 5 4 1 1 1 1.003 5 5 4 3 5 5 1.004 5 5 5 5 5 5 1.005 5 5 5 5 5 5 1.006 2 5 5 3 3 5 1.007 4 5 5 5 5 5 1.009 5 5 5 5 5 5 1.010 4 5 5 3 4 5 1.012 5 5 5 5 5 5 1.014 3 5 4 5 4 5 1.016 4 5 5 5 5 5 1.037 5 5 5 4 5 5 1.041 4 5 5 5 5 5 1.044 5 5 5 5 5 5 1.067 5 5 2 5 5 5 1.068 2 5 3 4 4 4 1.069 3 5 3 5 5 5 1.070 5 5 5 5 5 5 1.071 3 5 3 5 4 5 1.072 2 5 2 5 4 5 1.073 3 5 3 5 5 5 1.074 5 5 5 5 5 5 1.075 4 5 4 5 5 5 1.076 4 5 2 5 5 5 1.077 5 5 5 5 5 5 1.078 1 5 3 3 2 4 1.079 1 5 1 1 1 5 1.080 2 5 2 1 1 5 1.081 2 5 3 4 2 4 1.082 1 5 1 2 1 3 1.083 2 5 1 3 1 5 1.084 4 5 3 2 1 5 1.085 5 5 5 3 4 5 1.086 4 5 3 4 2 5 1.087 5 5 5 5 5 5