Synthesis and Chemistry of Agrochemicals IV - American Chemical

Chapter 9

Alkyl 3-[2,4-Disubstituted-4,5-dihydro-3-methyl5-oxo-1H-1,2,4-triazol-1-yl)phenyl]propenoate Derivatives

Downloaded by UNIV OF CALIFORNIA SAN DIEGO on April 14, 2016 | http://pubs.acs.org Publication Date: May 5, 1995 | doi: 10.1021/bk-1995-0584.ch009

Synthesis and Structure—Activity Relationships George Theodoridis, James T. Bahr, Bruce L. Davidson, Stephen E. Hart, Frederick W. Hotzman, Kathleen M. Poss, and S. F. Tutt Agricultural Chemical Group, FMC Corporation, P.O. Box 8, Princeton, NJ 08543 Structure-activity investigations of the five position of the aryl ring of 1-(2,4,5-trisubstitutedphenyl)-4,5-dihydro-1,2,4-triazol-5(H)-one 1 resulted in the discovery of a highly active class of postemergence herbicides with excellent control of key broadleaf weeds. The synthesis and structure-activity relationship of these compounds are discussed. The weed control and crop selectivity of F8426 are presented in detail.

1 Our previous structure-activity investigations of aryltriazolinone herbicides 1, have resulted in a number of significant discoveries, including sulfentrazone (1, X, Y = CI; R = NHSO2CH3), a soybean herbicide currently in development by FMC Corporation (1,2,3). Recently we discovered that a 2-halopropionate ester group at the five position of the phenyl ring results in a highly active class of postemergence herbicides with good cereal tolerance (4).

1 0097-6156/95/0584-()090$12.00/0 © 1995 American Chemical Society

Baker et al.; Synthesis and Chemistry of Agrochemicals IV ACS Symposium Series; American Chemical Society: Washington, DC, 1995.

9. THEODORIDIS ET AL.

Alkyl Phenylpropenoates

91


F8426, is a new experimental postemergence herbicide in development at FMC Corporation (5). The mechanism of action was found to involve the inhibition of the enzyme protoporphyrinogen oxidase (Protox), which results in the build-up of a photodynamic toxicant, protoporphyrin IX (6-11). Applied postemergence, F8426 herbicide causes rapid dessication of sensitive weed species at field rates between 4 and 35 g/ha. Soil activity of F8426 is observed at higher rates, 70 to 500 g/ha.

F8426 Synthesis Synthesis of this class of compounds involves the use of substituted arylhydrazines as starting materials to prepare the corresponding substituted aniline triazolinone intermediates 2, as previously reported (72). The Meerwein reaction was used for the synthesis of the alkyl halopropionate chain. Treatment of the aniline intermediate 2 with tert-butyl nitrite, alkyl acrylate and copper II chloride in acetonitrile gives the desired product 3 in excellent yields (4,13) (Figure 1).


92

SYNTHESIS AND CHEMISTRY OF AGROCHEMICALS TV

An alternative synthesis involves the use of 2-chloro-4-fluoro-5nitrobenzaldehyde 4 as starting materials (4). The aldehyde is protected during the synthesis of the heterocycle by reacting it with 1,3-propanedithiol. The protecting group was then removed to regenerate the aldehyde 6 which was reacted with (carbethoxymethylene) triphenylphosphorane. The trans isomer 7 is obtained which can then be hydrogenated to the saturated propionate derivative 8 as shown in Figure 2.


CI

OHC

Several steps N0

2

Aq. acetone 0°C

Cl

OHC N=< CH

3

(Ph )P=CHC0 Et 3

X Et0 C

R0

5

j Et0 C

2

2

8

7

Figure 2. Alternative synthesis of aryltriazolinones.


2



93

Biological Testing The compounds described were tested preemergence and postemergence on various weeds and crops in the greenhouse. All biological data for Tables I-VIII refer to postemergence application. The seeds of the plant test species were planted in furrows in steam-sterilized sandy loam soil contained in disposable fiber flats. A topping soil of equal portions of sand and sandy loam soil was placed uniformly on top of each flat to a depth of approximately 0.5 cm. The flats were placed in a greenhouse and watered for 8-10 days, then the foliage of the emerged test plants was sprayed with a solution of the test compound in acetone-water containing up to 5 ml liter - sorbitan monolaurate emulsifier/solubilizer. The concentration of the test compound in solution was varied to give a range of application rates. Phytotoxicity data were taken as percentage control, determined by a method similar to the 0-100 rating system described previously (14) , with 0% control of crops or weeds showing no effect relative to controls, and 100% control indicating complete crop or weed destruction. The biological data in Tables I- VIII are presented as the postemergence application rate required to give 90% control as compared with untreated plants. In general, the 95% confidence interval for individual ED90 values in these tests is ED90/2 to ED90x2 (e.g., the CI for an ED90 of 30 g ha" is 15-60). The weeds species used in this study were morningglory and velvetieaf.


1

1

Structure-Activity Relationships Aromatic Substitution. The pre- and postemergence activity of aryl triazolinone herbicides is greatly affected by the substituents in the aromatic portion of the molecule. We have previously discussed the effect that various chemical groups at position five of the phenyl ring have on preemergence biological activity, weed control spectrum and crop tolerance of aryl triazolinones (12). In that study we concluded that the substituents at position five of the phenylringnot only influence the degree of preemergence herbicidal activity but also the weed spectrum and crop tolerance. In the present work we found that the substituents at position five of the phenyl ring also influence the degree of postemergence biological activity as well as the weed spectrum and crop tolerance. For instance, R groups such as the methoxy and the propargyloxy resulted in compounds that provided good broadleaf weed control at low application rates, but their presence also resulted in high wheat injury. When R=NH2 or O C ^ s , the resulting compounds were considerably less active than the parent compound, R=H. In contrast, the ethyl 2-chloropropionate group is able to provide both good weed control and wheat tolerance (Table I). The structure-activity relationship of chemical groups at the 2 and 4 position of the phenylringparallels that of related aryl triazolinone herbicides (12). Compounds where X=F and Y=C1 provided the best postemergence biological activity, with compounds where X=F and Y=Br providing comparable activity. When X and Y were both chlorine or fluorine there was a significant reduction of activity (Table II). The ester group was replaced with a variety of other chemical groups, all of which resulted in a dramatic reduction in biological activity. This was particularly true when the ester group was replaced with a methanesulfonyl or a phenyl group (Table III).


94



Table I. Effect of R Groups at Position Five of Aromatic Ring on the Postemergence Biological Activity of Aryltriazolinones

CH

3

Rate required to provide 90% control of weeds tested

R CH CHClC0 Et OCH C=CH 2

2

2

OCH H

3

OC6H NH

5

2

Rate required to provide 20% wheat injury (g/ha) 250 8 100 250 100 500

(g/ha) 15 15 100 250 1000 2000

Table II. Effect of Groups X and Y of Aromatic Ring on Postemergence Biological Activity

CH

Substituents X Y F F CI F

CI Br CI F

3

Rate required to provide 90% control of weeds tested (g/ha) 15 15 30 300




95

Table HI. Effect of R3 Group on Postemergence Biological Activity


K.. Rate required to provide 90% control of weeds tested

R3

(g/ha) C0 Et PO(OEt) CN

15 250 300 >300 >300

2

2

SO2CH3

C H 6

5

Several carboxylic acid derivatives were prepared including a variety of esters, amides and substituted amides. The ester derivatives provided the best postemergence broadleaf weed activity and wheat tolerance. The ester derivatives were more active than the corresponding acid derivatives. The amide derivatives, though fairly active, resulted in higher wheat phytotoxicity than the esters (Table IV). Table IV. Effect of Carboxylic Acid Derivatives on Postemergence Biological Activity

R4

OCH3 OCH2CH3

OH NH

2

NHCH3

Rate required to provide 90% control of weeds tested

Rate required to provide 20% wheat injury

(g/ha)

(g/ha)

30 30 125 125 125

125 125 60 30 60


96


Of all the chemical groups investigated at the alpha-position of the propionate group, X=H and Y=C1 gave the highest biological activity. Replacement of the alphachlorine with hydrogen, bromine or a methyl group resulted in a reduction of biological activity (Table V).


Table V . Effect of Substituents in the Propionate Group on Postemergence Biological Activity

CH

Substituents

3

X

Y

Rate required to provide 90% control of weeds tested (g/ha)

H CH H H H

CI CI Br H CH

15 30 300 300 300

3

3

F8426 Herbicidal Activity F8426 was tested in small plot field trials in the United States, Canada, Europe, selected east Asian countries and Australia during several seasons. The United States field performance of F8426 alone at 28 to 40 days after treatment at 35 grams per hectare is shown here (Table VI). These data are from the 1990 to 1992 testing seasons for the 50 and 240 gram per liter EC formulations. The number of observations varies from as few as two for common sunflower to as many as 19 for kochia. Weed control varies from only 61% control of wild buckwheat to 98% control of field pennycress. For most species control is in the 80 to 90% range; wild buckwheat and three of the mustard species were less well controlled. For some weed species F8426 does not kill the growing point of all plants present. We have conducted one field trial with sulfonylurea-resistant kochia. Both the EC formulation of F8426, and F8426 combined with 2,4-D ester, provided good to excellent control of this kochia population, while Harmony® Extra herbicide failed to provide either control or suppression (Table VII).




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Table VI. Postemergence Weed Control of F8426 Under Field Conditions in the United States Species

35 g/ha

kochia pigweed Russian thistle wild buckwheat common lambsquarters common sunflower velvetleaf shepherd's purse smallseed falseflax blue mustard tansy mustard flixweed bushy wallflower wild mustard field pennycress

87(19) 85(7) 83(9) 61(18) 88(9) 94(2) 92(5) 97(4) 69(3) 73(10) 70(7) 83(14) 91(5) 83(14) 98(5)

Table VII. F8426 Postemergence Control of Sulfonyl Urea-Resistant Kochia % Kochia Control (30 DAT) Harmony® Extra herbicide 26 g/ha

25

F8426 35 g/ha

83

F8426 35 g/ha plus 2,4-D esterl40 g/ha

91

2,4-D ester 280 g/ha plus Dicamba 140 g/ha

95

F8426 has similar tolerance in other cereal crops. A side-by-side field trial was conducted to compare multiple cultivars and multiple cereal crops. The injury at seven days after treatment to three-leaf stage crops ranged from 4% to 8% at the 35 gram per hectare rate. At the 70 grams per hectare rate, the injury varied from 7% to 13%. There were no significant differences among cultivars nor among the several cereal crops (Table VIII). In Europe, F8426 provides control or strong suppression of several important weeds common in cereal crops when applied postemergence. At an application rate of 20 g Al/ha F8426 controlled Galium aparine, Veronica hederfolia, Veronica persica, Capsella bursa-pastoris, Chenopodium album, and Lamium purpureum (5).


98


Table Vm. Cereal Tolerance to Postemergence Application of F8426


Side-by-side Trial Crop/cultivar

Necrosis at 7 DAT a 70 g/ha 35 g/h; 11 7 10 6 10 6 %

Spring Wheat

Butte Marshall Vance

Winter Wheat

Cardinal Caldwell Howell

5 6 5

11 10 8

Spring Barley

Robust Azure IFS:2619D

7 7 7

13 11 11

Winter Barley

Pike Wysor

8 6

9 11

Winter Oats

Ogle

6

12

Winter Rye

IFS:5432

4

7

Summary F8426 is a new postemergence broadleaf herbicide for use in cereal crops. It will offer growers a new, low-rate, herbicide for cereals. It should be a significant contributor to the management of sulfonylurea-resistant broadleaf weed populations. Literature Cited

1. 2. 3.

4. 5. 6.

Theodoridis, G. U.S. Patent 4,818,275, 1989. Theodoridis, G. U.S. Patent 5,041,155, 1991. Van Saun, W.A.; Bahr, IT.; Crosby, G.A.; Fore, Z.A.; Guscar, H.L.; Harnish, W.N.; Hooten, R.S.; Marquez, M.S.; Parrish, D.S.; Theodoridis, G.; Tymonko, J.M.; Wilson, K.R.; Wyle, M.J. Proc. Br. Crop ProtectionConf.,Weeds, 1991, pp 77-82. Poss, K.M. U.S. Patent 5,125,958, 1992. Van Saun, W.A.; Bahr,J.T.;Bourdouxhe, L.J.; Gargantiel, F.J.; Hotzman, F.W.; Shires, S.W.; Sladen, N.A.; Tutt, S.F.; Wilson, K.R.; Proc. Br. Crop Protection Conf., Weeds, 1993, pp 19-22. Matringe, M.; Scalla, R. Pest. Biochem.Physiol.1988, 32, 164.


9. THEODORIDIS ET AL. 7. 8. 9. 10.


11. 12.

13. 14.


99

Witkowski, D.A.; Hailing, B.P. PlantPhysiol.1988, 87, 632. Ibid, 1989, 90, 1239. Matringe, M.; Camadro, J-M.; Labbe, P.; Scalla, R. Biochem J. 1989, 260, 231. Matringe, M.; Camadro, J-M.; Labbe, P.; Scalla, R. FEBS Letters 1989, 245, 35. Mito, N.; Sato, R.; Miyakado, M.; Oshio, H.; Tanaka, S. Pest. Biochem. Physiol. 1991, 40, 128. Nandihalli, U.B.; Liebl, C.A. Pesticide Science. 1991, 31, 9. Theodoridis, G.; Baum, J.S.; Hotzman, F.W.; Manfredi, M.C.; Maravetz, L.L.; Lyga, J.W.; Tymonko, J.M; Wilson. K.R.; Poss, K.M.; Wyle, M.J. In Synthesis and Chemistry of Agrochemicals III, edited by Baker, D.R.; Fenyes, J.G.; Steffens, J.J.; ACS Symposium Series No. 504; American Chemical Society; Washington, D.C. 1992, pp 134-146. Doyle, M.P.; Siegfried, B.; Elliot, R.C.; Dellareia, J.F. J. Org. Chem. 1977, 42, 2431. Frans, R.E.; Talbert, R.E.; Research Methods in Weed Science, 2nd edn, ed. B. Truelove, Auburn, AL, 1977, pp 15-23.

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Synthesis and Chemistry of Agrochemicals IV - American Chemical

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