Plant growth and development modification using benzoxazole derivatives

Abstract

Benzoxazole compounds of the following structural formula modify the growth and development of plants: ##STR1## wherein U is selected from -hydrogen, -halogen, -lower alkyl, -lower alkenyl, -phenylmethyl, -phenyl, -nitro, -hydroxycarbonyl, -phenylcarbonyl, -halophenylcarbonyl, -phenylthio, -phenylsulfoxy, -phenylsulfonyl, and a substituent of the formula--OZ in which Z is -aryl or -aryl carring 1 or 2 substituents independently selected from -halogen, -lower alkyl, -lower haloalkyl, -lower alkoxy, -acetamido, and -phenyl;V is selected from -hydrogen, -halogen and -lower alkyl, or U and V taken together are -C.sub.4 H.sub.4 -- joining adjacent ring positions; andW is selected from -hydrogen, -lower alkyl optionally substituted with -alkoxycarbonyl, and an agriculturally acceptable cation.

Description

This invention is in the field of organic chemical compounds; more specifically, it pertains to novel 2-(2-oxycarbonylphenyl)benzoxazoles, processes and intermediates thereto, plant growth and development modifying compositions containing 2-(2-oxycarbonylphenyl)benzoxazoles, and to the use of 2-(2-oxycarbonylphenyl)benzoxazoles for modifying the growth and development of plants.

A number of organic chemical compounds modify the growth and development of plants. Application of an organic chemical to plants may cause death of the plants. Such chemicals are referred to as herbicides. Although broad spectrum herbicides have recognized utility, herbicidal activity is often more desirable if it is selective, sparing crops, but killing weeds. Occasionally organic compounds are discovered which are not simply nutrients, but, when applied in the recommended manner, selectively modify the normal growth and development of plants and do not kill them.

Beneficial effects from such modification include increasing the yield of fruit, seeds, fiber, or other plant products. Another beneficial effect may be an increase in the nutritional value of food products derived from the plants. It is a beneficial effect of some compounds to facilitate harvesting the plant product. Yet another beneficial effect in certain cases is an increase in the products's storage life. Such chemical compounds, beneficial to plants in small amounts, are referred to as plant growth regulators. Plant growth and development modifications leading to such effects include, but are not limited to: root initiation; set, development, ripening and abscission of fruits; plant size and shape; suppression of lodging; control of axillary buds and lateral shoots; metabolism regulation, including senescence; breaking or enforcing dormancy in seeds, buds, and storage organs; promotion or delay of flowering; defoliation; desiccation; and growth promotion under stress.

Sometimes an organic chemical compound displays plant growth and development regulation characterized by both herbicidal activity and plant growth regulator activity depending upon the species of plant, the time of application in the plant growth cycle, the site of application, and the amount of chemical employed, i.e., the application rate.

The plant growth and development modifying 2-(2-oxycarbonylphenyl)benzoxazoles of this invention are in the latter category. In general, they can be made to behave as either herbicides or plant growth regulators depending upon the way they are used.

A 2-(2-oxycarbonylphenyl)benzoxazole is a condensed ring heteroaromatic compound containing the following structural unit: ##STR2## The ring atom numbering scheme is shown for convenient reference.

Both 2-(3-carboxyphenyl)benzoxazole and the (4-carboxyphenyl)isomer are known compounds, as are the corresponding methyl esters; see J. Gen. Chem. USSR, 963 (1968). U.S. Pat. No. 3,947,582 discloses related benzoxazole phenylacetic acids and their pharmaceutical utility. The herbicidal activity of certain 2-phenylbenzoxazoles is disclosed in GB 1,090,497, and U.S. Pat. No. 4,319,026 describes 2-substituted benzoxazole plant growth regulators.

According to the present invention 2-(2-oxycarbonylphenyl)benzoxazoles of the following formula have been found to modify the growth and development of plants: ##STR3## wherein U is selected from -hydrogen, -halogen, -lower alkyl, -lower alkenyl, -phenylmethyl, -phenyl, -nitro, -hydroxycarbonyl, -phenylcarbonyl, -halophenylcarbonyl, -phenylthio, -phenylsulfoxy, -phenylsulfonyl, and a substituent of the formula

--OZ in which Z is -aryl or -aryl carrying 1 or 2 substituents independently selected from -halogen, -lower alkyl, -lower haloalkyl, -lower alkoxy, -acetamido, and -phenyl; V is selected from -hydrogen, -halogen, and -lower alkyl, or U and V taken together are --C.sub.4 H.sub.4 -- joining adjacent ring positions; and W is selected from -hydrogen, -lower alkyl optionally substituted with -alkoxycarbonyl, and an agriculturally acceptable cation.

In the aforesaid description and wherever employed in this application the terms "halogen" or "halo" mean fluorine, chlorine and bromine. Similarly, the terms "lower alkyl" and "lower alkenyl" mean a straight or branched chain containing 1 to 6, preferably 1 to 4, carbon atoms, and the term "lower alkoxy" contemplates bonded to oxygen a straight or branched chain containing 1 to 6, preferably 1 to 4, carbon atoms. The terms "haloalkyl," "halophenyl," or the like mean one or more hydrogen atoms has been replaced by halogen. The term "aryl" includes phenyl, naphthyl, heterocyclics such as 2,2-dimethylbenzofuranyl, and equivalents thereof. "Agriculturally acceptable cations" include, but are not limited to, alkali and alkaline earth metals such as sodium, potassium, calcium, lithium, and magnesium, or other metals such as copper, zinc, aluminum or iron; ammonium, mono-, di-, or tri-substituted ammonium, such as methylammonium, 1-methylethylammonium, diethylammonium, triethylammonium, hexylammonium, dodecylammonium, ethanolammonium, diethanolammonium, hexanolammonium, or dodecanolammonium.

Many of the 2-(2-oxycarbonylphenyl)benzoxazoles are new compounds, constituting one aspect of this invention. However, the instant invention also includes plant growth and development modifying compositions comprising in admixture with an agriculturally acceptable carrier a plant growth and development modifying effective amount of at least one of the aforesaid 2-(2-oxycarbonylphenyl)benzoxazoles. Furthermore, the invention includes as another aspect the method of modifying the growth and development of plants which comprises applying to the locus where such modification is desired a plant growth and development modifying effective amount of at least one 2-(2-oxycarbonylphenyl)benzoxazole within the aforesaid description.

Among the aforesaid 2-(2-oxycarbonylphenyl)benzoxazoles the most interesting from the standpoint of overall activity are generally the acids and salts, i.e., compounds in which W is either -hydrogen or an agriculturally acceptable cation. Within this set it is preferred that V be -hydrogen and that U be a 5-, 6- or 7-substituent, especially a 5- or 6-substituent. Other attractive compounds are those in which U and V together are --C.sub.4 H.sub.4 -- joining either the 4- and 5-positions or the 5- and 6-positions.

In those compounds in which V is -hydrogen the most attractive properties generally are seen in those compounds wherein U is -alkyl (especially -methyl), -phenyl, -phenylthio, -phenylsulfoxy, -phenylsulfonyl, -phenylcarbonyl, -halophenylcarbonyl, and especially -OZ. Preferred substituents Z include -phenyl, especially phenyl carrying -halogen, haloalkyl, or -acetamido substitution; -naphthyl; and 2,2-dimethyl-7-benzofuranyl.

If the 2-(2-oxycarbonylphenyl)benzoxazoles are to be used as herbicides, attractive specific compounds include 2-(2-carboxyphenyl)-6-phenoxybenzoxazole; 2-(2-carboxyphenyl)-6-(4-chlorophenoxy)benzoxazole; 2-(2-carboxyphenyl)-6-(2,4-dichlorophenoxy)benzoxazole; 2-(2-carboxyphenyl)-6-(2-chloro-4-trifluoromethylphenoxy)benzoxazole; and agriculturally acceptable cation salts of 2-(2-carboxyphenyl)-6-(2,4-dichlorophenoxy)benzoxazole, 2-(2-carboxyphenyl)-6-(2-chloro-4-trifluoromethyl phenoxy)benzoxazole, and 2-(2-carboxyphenyl)-6-(4-methylphenoxy)benzoxazole. Among the aforesaid herbicidal compounds, an agriculturally acceptable cation salt of 2-(2-carboxyphenyl)-6-(2-chloro-4-trifluoromethylphenoxy)benzoxazole is preferred for both preemergence and postemergence application.

With regard to plant growth regulation, the compounds in which W is -hydrogen or an agriculturally acceptable cation are substantially equivalent. Noteworthy plant growth regulating 2-(2-oxycarbonylphenyl)benzoxazoles include 2-(2-carboxyphenyl)-6-phenylbenzoxazole; 2-(2-carboxyphenyl)-5-phenoxybenzoxazole; 2-(2-carboxyphenyl)-6-phenoxybenzoxazole; 2-(2-carboxyphenyl)-6-(2-chloro-4-trifluoromethylphenoxy)benzoxazole; 2-(2-carboxyphenyl)-6-(4-methylphenoxy)benzoxazole; 2-(2-carboxyphenyl)-6-(phenylsulfinyl)benzoxazole; 2-(2-carboxyphenyl)-6-(4-acetamidophenoxy)benzoxazole; 2-(2-carboxyphenyl)-6-(2,2-dimethyl-7-benzofuranoxy)benzoxazole; 2-(2-carboxyphenyl)-naphtho[2,1-d]oxazole; 2-(2-carbomethoxyphenyl)-6-phenoxybenzoxazole; 2-(2-carbomethoxyphenyl)-6-(.alpha.-naphthoxy)benzoxazole; and agriculturally acceptable cation salts of 2-(2-carboxyphenyl)-6-(2-chloro-4-trifluoromethylphenoxy)benzoxazole.

Among the aforesaid plant growth regulators 2-(2-carboxyphenyl)-6-phenylbenzoxazole, 2-(2-carboxyphenyl)-6-(2-chloro-4-trifluoromethylphenoxy)benzoxazole, and especially 2-(2-carboxyphenyl)-5-phenoxybenzoxazole display promising activity.

The 2-(2-oxycarbonylphenyl)benzoxazoles of this invention can be prepared by adaptations of synthesis techniques described in the literature. The following general technique is employed: ##STR4## Those compounds in which W is other than methyl are readily derived from the esters by known methods. The starting 2-carbomethoxybenzaldehyde can be prepared by the method of Brown and Sargent, J. Chem. Soc. (C), 1818 (1969), while the appropriately substituted 2-aminophenol is readily derived from the corresponding 2-nitrophenol, e.g., by catalytic hydrogenation.

The condensation of 2-carbomethoxybenzaldehyde with the appropriately substituted 2-aminophenol, producing a Schiff base, as well as cyclization of the latter, can be effected by the methods of Stephens and Bower, J. Chem. Soc., 2971 (1949). These processes will be clarified upon reference to the following Example.

EXAMPLE 58

2-(2-Carbomethoxyphenyl)-6-(2-chloro-4-trifluoromethylphenoxy)benzoxazole

A solution of 2.3 grams (0.0008 mole) 2-amino-5-((2-chloro-4-trifluoromethylphenoxy)phenol in ethanol was heated on a steam bath, and 1.2 grams (0.008 mole) of o-carbomethoxybenzaldehyde in ethanol was added. The reaction mixture was then heated on the steam bath for an additional hour. The cooled reaction mixture was concentrated under reduced pressure to give 3.4 g of N-(o-carbomethoxybenzylidene)-2-hydroxy-4-(2-chloro-4-trifluoromethylphenoxy)aniline that solidified on standing; m.p. 82.degree.-85.degree. C.

To a stirred solution of 2.7 grams (0.006 mole) N-(o-carbomethoxybenzylidene)-2-hydroxy-4-(2-chloro-4-trifluoromethylphenoxy)aniline in 25 ml of chloroform was added portionwise 2.9 grams (0.007 mole) lead tetraacetate. The reaction mixture was stirred for an additional hour, then washed sequentially with three portions of water and an aqueous saturated sodium chloride solution. The organic layer was concentrated under reduced pressure to a residual oil. The oil was dissolved in methylene chloride and passed through a column of activated magnesium silicate. The appropriate fractions were combined and concentrated under reduced pressure to give 2.2 grams of 2-(o-carbomethoxyphenyl)-6-(2-chloro-4-trifluoromethylphenoxy)-benzoxazole as an oil. The nmr spectrum was consistent with the proposed structure.

Analysis: nmr (.delta., CHCl.sub.3): 3.87 (s, 3H); 6.93-8.23 (m, 10H).

Following is a list of other 2-(2-oxycarbonylphenyl)benzoxazoles within the scope of this invention prepared by similar techniques, together with mp (.degree.C.) where applicable.

______________________________________Ex-am-ple______________________________________ 1 2-(2-Carboxyphenyl)benzoxazole, mp 211-214. 2 2-(2-Carboxyphenyl)-5-chlorobenzoxazole, mp 205-207. 3 2-(2-Carboxyphenyl)-7-chlorobenzoxazole, mp 235-236. 4 2-(2-Carboxyphenyl)-5,7-dichlorobenzoxazole, mp 199-202, dec. 5 2-(2-Carboxyphenyl)-4-methylbenzoxazole, mp 155-156. 6 2-(2-Carboxyphenyl)-5-methylbenzoxazole, mp 203-205. 7 2-(2-Carboxyphenyl)-6-methylbenzoxazole, mp 243-246. 8 2-(2-Carboxyphenyl)-7-methylbenzoxazole, mp 225-227. 9 2-(2-Carboxyphenyl)-7-(2-methylpropyl)benzoxazole, mp 160-162.10 2-(2-Carboxyphenyl)-5-(1,1-dimethylethyl)benzoxazole, mp 68-73.11 2-(2-Carboxyphenyl)-7-(2-methyl-2-propenyl)benzoxazole, mp 147-150.12 2-(2-Carboxyphenyl)-5,7-dimethylbenzoxazole, mp 204-206.13 2-(2-Carboxyphenyl)-5-nitrobenzoxazole, mp 238-241.14 2-(2-Carboxyphenyl)-5-carboxybenzoxazole, mp 227, dec.15 2-(2-Carboxyphenyl)-5-phenylbenzoxazole, mp 171-17916 2-(2-Carboxyphenyl)-6-phenylbenzoxazole, mp 205-206.17 2-(2-Carboxyphenyl)-7-phenylbenzoxazole, mp 238-240.18 2-(2-Carboxyphenyl)-5-phenoxybenzoxazole, mp 142-144.19 2-(2-Carboxyphenyl)-6-phenoxybenzoxazole, mp 154-155.20 2-(2-Carboxyphenyl)-6-(4-chlorophenoxy)benzoxazole, mp 148-149.21 2-(2-Carboxyphenyl)-6-(2,4-dichlorophenoxy)benzoxazole, mp 181-182.22 2-(2-Carboxyphenyl)-6-(3,4-dichlorophenoxy)benzoxazole, mp 174-176.23 2-(2-Carboxyphenyl)-6-(2-chloro-4-trifluoromethyl- phenoxy)benzoxazole, mp 175-176.24 2-(2-Carboxyphenyl)-6-(4-methylphenoxy)benzoxazole, mp 169-170.25 2-(2-Carboxyphenyl)-6-(4-methoxyphenoxy)benzoxazole, mp 159-160.26 2-(2-Carboxyphenyl)-6-(4-phenylphenoxy)benzoxazole, mp 198-200.27 2-(2-Carboxyphenyl)-6-(.alpha.naphthoxy)benzoxazole, mp 162-164.28 2-(2-Carboxyphenyl)-6-(.beta. naphthoxy)benzoxazole, mp 154-155.29 2-(2-Carboxyphenyl)-6-phenylthiobenzoxazole, mp 146-147.30 2-(2-Carboxyphenyl)-6-(phenylsulfinyl)benzoxazole, mp 135-141.31 2-(2-Carboxyphenyl)-6-(phenylsulfonyl)benzoxazole, mp 201-203.32 2-(2-Carboxyphenyl)-5-benzoylbenzoxazole, mp 173-174.33 2-(2-Carboxyphenyl)-5-(4-chlorobenzoyl)benzoxazole, mp 165-168.34 2-(2-Carboxyphenyl)-naphtho[1,2-d]oxazole, mp 181-183.35 2-(2-Carboxyphenyl)-naphtho[2,3-d]oxazole, mp 196-198.36 2-(2-Carbomethoxyphenyl)benzoxazole, liquid.37 2-(2-Carbomethoxyphenyl)-5-chlorobenzoxazole, mp 76-80.38 2-(2-Carbomethoxyphenyl)-7-chlorobenzoxazole, mp 92-93.39 2-(2-Carbomethoxyphenyl)-5,7-dichlorobenzoxazole, mp 106-107.40 2-(2-Carbomethoxyphenyl)-4-methylbenzoxazole, liquid.41 2-(2-Carbomethoxyphenyl)-5-methylbenzoxazole, liquid.42 2-(2-Carbomethoxyphenyl)-6-methylbenzoxazole, liquid.43 2-(2-Carbomethoxyphenyl)-7-methylbenzoxazole, liquid.44 2-(2-Carbomethoxyphenyl)-7-(2-methylpropyl)benzoxazole, liquid.45 2-(2-Carbomethoxyphenyl)-5-(1,1-dimethylethyl)benzox- azole, liquid.46 2-(2-Carbomethoxyphenyl)-7-(2-methyl-2-propenyl)- benzoxazole, liquid.47 2-(2-Carbomethoxyphenyl)-5,7-dimethylbenzoxazole, liquid.48 2-(2-Carbomethoxyphenyl)-5-nitrobenzoxazole, mp 134-135.49 2-(2-Carbomethoxyphenyl)-5-carboxybenzoxazole, mp 201-202.50 2-(2-Carbomethoxyphenyl)-5-phenylbenzoxazole, liquid.51 2-(2-Carbomethoxyphenyl)-6-phenylbenzoxazole, mp 83-83.52 2-(2-Carbomethoxyphenyl)-7-phenylbenzoxazole, mp 92-95.53 2-(2-Carbomethoxyphenyl)-5-phenoxybenzoxazole, liquid.54 2-(2-Carbomethoxyphenyl)-6-phenoxybenzoxazole, liquid.55 2-(2-Carbomethoxyphenyl)-6-(4-chlorophenoxy)benzoxazole, liquid.56 2-(2-Carbomethoxyphenyl)-6-(2,4-dichlorophenoxy)benzox- azole, liquid.57 2-(2-Carbomethoxyphenyl)-6-(3,4-dichlorophenoxy)benzox- azole, mp 75-77.59 2-(2-Carbomethoxyphenyl)-6-(4-methylphenoxy)benzoxazole, liquid.60 2-(2-Carbomethoxyphenyl)-6-(4-methylphenoxy)benzoxazole, liquid.61 2-(2-Carbomethoxyphenyl)-6-(4-acetamidophenoxy)benzox- azole, mp 62-65.62 2-(2-Carbomethoxyphenyl)-6-(4-phenylphenoxy)benzoxazole, mp 112-114.63 2-(2-Carbomethoxyphenyl)-6-(.alpha.-naphthoxy)benzoxazole, liquid.64 2-(2-Carbomethoxyphenyl)-6-(.beta.-naphthoxy)benzoxazole, mp 101-103.65 2-(2-Carbomethoxyphenyl)-6-phenylthiobenzoxazole, mp 79-80.66 2-(2-Carbomethoxyphenyl)-6-(phenylsulfinyl)benzoxazole, mp 119-120.67 2-(2-Carbomethoxyphenyl)-6-(phenylsulfonyl)benzoxazole, mp 140-141.68 2-(2-Carbomethoxyphenyl)-5-benzoylbenzoxazole, mp 115-116.69 2-(2-Carbomethoxyphenyl)-5-(4-chlorobenzoyl)benzoxazole mp 128-130.70 2-(2-Carbomethoxyphenyl)-naphtho[1,2-d]oxazole, liquid.71 2-(2-Carbomethoxyphenyl)-naphtho[2,3-d]oxazole, mp 133-134.72 2-(2-Carbomethoxyphenyl)benzoxazole, 1-methylethyl- amine salt, mp 128-132.73 2-(2-Carboxyphenyl)-5-chlorobenzoxazole, 1-methylethyl- amine salt, mp 146-150.74 2-(2-Carboxyphenyl)-7-chlorobenzoxazole, 1-methyl- ethylamine salt, mp 164-166.75 2-(2-Carboxyphenyl)-5,7-dichlorobenzoxazole, 1-methyl- ethylamine salt, mp 111-116.76 2-(2-Carboxyphenyl)-4-methylbenzoxazole, 1-methyl- ethylamine salt, mp 161-163.77 2-(2-Carboxyphenyl)-5-methylbenzoxazole, 1-methylethyl- amine salt, mp 150, dec.78 2-(2-Carboxyphenyl)-6-methylbenzoxazole, 1-methylethyl- amine salt, mp 149-151.79 2-(2-Carboxyphenyl)-7-methylbenzoxazole, 1-methylethyl- amine salt, mp 164-166.80 2-(2-Carbomethoxyphenyl)-5-(1,1-dimethylethyl)benzox- azole, 1-methylethylamine salt, mp 70-75, dec.81 2-(2-Carboxyphenyl)-5-nitrobenzoxazole, 1-methylethyl- amine salt, mp 110, dec.82 2-(2-Carboxyphenyl)-5-phenylbenzoxazole, 1-methylethyl- amine salt, mp 170-176, dec.83 2-(2-Carboxyphenyl)-6-phenylbenzoxazole, 1-methylethyl- amine salt, mp. 176-179.84 2-(2-Carboxyphenyl)-7-phenylbenzoxazole, 1-methylethyl- amine salt, mp 192-193.85 2-(2-Carboxyphenyl)-5-phenoxybenzoxazole, 1-methylethyl- amine salt, mp 118-120.86 2-(2-Carboxyphenyl)-6-(2,4-dichlorophenoxy)benzoxazole, 1-methylethylamine salt, mp 70-73, hygroscopic.87 2-(2-Carboxyphenyl)-6-(3,4-dichlorophenoxy)benzoxazole, 1-methylethylamine salt, mp 129-130.88 2-(2-Carboxyphenyl)-6-(2-chloro-4-trifluoromethylphen- oxy)benzoxazole, 1-methylethylamine salt, mp 69-71.89 2-(2-Carboxyphenyl)-6-(4-methylphenoxy)benzoxazole, 1-methylethylamine salt, mp 175-178.90 2-(2-Carboxyphenyl)-6-(4-methylphenoxy)benzoxazole, 1-methylethylamine salt, mp 154-155.91 2-(2-Carboxyphenyl)-6-(4-phenylphenoxy)benzoxazole, 1-methylethylamine salt, mp 171-174.92 2-(2-Carboxyphenyl)-6-(.alpha.-naphthoxy)benzoxazole, 1- methylethylamine salt, mp 174-177.93 2-(2-Carboxyphenyl)-6-(.beta.-naphthoxy)benzoxazole, 1- methylethylamine salt, mp 163-166.94 2-(2-Carboxyphenyl)-6-phenylthiobenzoxazole, 1-methyl- ethylamine salt, mp. 128-129.95 2-(2-Carboxyphenyl)-naphtho[1,2-d]oxazole, 1-methyl- ethylamine salt, mp 170-173.96 2-(2-Carboxyphenyl)-naphtho[2,3-d]oxazole, 1-methyl- ethylamine salt, mp 177-181.97 2-(2-Carboxyphenyl)-5-phenylmethylbenzoxazole, mp 50-53.98 2-(2-Carboxyphenyl)-6-(4-acetamidophenoxy)benzoxazole, mp 208-209.99 2-(2-Carbomethoxyphenyl)-5-phenylmethylbenzoxazole, liquid.100 2-(2-Carbomethoxyphenyl)-6-(2,2-dimethyl-7-benzofuran- oxy)benzoxazole, liquid.101 2-(2-Carboxyphenyl)-6-(2,2-dimethyl-7-benzofuran- oxy)benzoxazole, mp 235-237.102 2-(Carbo-[2-(1-ethoxypropanoyl)oxy]phenyl)-5-phenyl- benzoxazole, liquid.103 [ 2-(1-ethoxypropanoyl)oxy]phenyl)-5-methyl- benzoxazole, mp 95-97.104 2-(Carbo-[2-(1-ethoxypropanoyl)oxy]phenyl)-6-(4-methyl- phenoxy)benzoxazole, liquid.105 2-(2-Carbomethoxyphenyl)-5-(4-methoxyphenoxy)benzoxa- zole, liquid.106 2-(2-Carboxyphenyl)-5-(4-methoxyphenoxy)benzoxazole, mp 214-215.107 2-(2-Carbomethoxyphenyl)-naptho[2,1-d]oxazole, liquid.108 2-(2-Carboxyphenyl)-naptho[2,1-d]oxazole, mp 228-230.109 2-(2-Carbomethoxyphenyl)-5-(2-chloro-4-trifluoromethyl- phenoxy)benzoxazole, liquid.110 2-(2-Carboxyphenyl)-5-(2-chloro-4-trifluoromethylphen- oxy)benzoxazole, mp 179-180.______________________________________

In the normal use of the aforesaid 2-(2-oxycarbonylphenyl)benzoxazole plant growth and development modifiers, the active compounds usually will be not employed free from admixture or dilution, but ordinarily will be used in a suitable formulated agricultural composition compatible with the method of application and comprising a plant growth and development modifying effective amount of at least one of said active compounds. Said benzoxazoles, like most pesticidal agents, may be blended with the agriculturally acceptable surface-active agents and carriers normally employed for facilitating the dispersion of active ingredients, recognizing the accepted fact that the formulation and mode of application of a plant growth and development modifier may affect the activity of the material. The present active compounds may be applied, for example, as sprays, dusts, or granules to the area where plant growth and development modification is desired, the type of application varying of course with the plant and the environment. Thus, the benzoxazole compounds of this invention may be formulated as granules of large particle size, as powdery dusts, as wettable powders, as emulsifiable concentrates, as solutions, and the like.

Granules may comprise porous or nonporous particles, such as attapulgite clay or sand, for example, which serve as carriers for said active compounds. The granule particles are relatively large, a diameter of about 400-2500 microns typically. The particles are either impregnated with the active compound from solution or coated with the compound, adhesive sometimes being employed. Granules generally contain 0.05-20% by weight, preferably 0.5-5%, active ingredient as the plant growth and development modifying effective amount. A typical granular formulation employed for evaluation purposes contains 95% attapulgite clay (24/48 mesh) and 5% 2-(2-carboxyphenyl)-6-phenylbenzoxazole.

Dusts are admixtures of said active compounds with finely divided solids such as talc, attapulgite clay, kieselguhr, pyrophyllite, chalk, diatomaceous earths, calcium phosphates, calcium and magnesium carbonates, sulfur, flours, and other organic and inorganic solids which act as carriers for the plant growth and development modifier. These finely divided solids have an average particle size of less than about 50 microns. A typical dust formulation useful for modifying the growth and development of plants contains by weight 5 parts 2-(2-carboxyphenyl)-6-phenylbenzoxazole and 95 parts talc.

The benzoxazole compounds of the present invention may be made into liquid concentrates by dissolution or emulsification in suitable liquids and into solid concentrates by admixture with talc, clays, and other known solid carriers used in the pesticide art. The concentrates are compositions containing, as a plant growth and development modifying effective amount, about 5-50% the benzoxazole by weight and 95-50% inert material, which includes surface-active dispersing, emulsifying, and wetting agents, but even higher concentrations of active ingredient may be employed experimentally. The concentrates are diluted with water or other liquids for practical application as sprays, or with additional solid carrier for use as dusts. Typical carriers for solid concentrates (also called wettable powders) include fuller's earth, clays, silicas, and other highly absorbent, readily wetted inorganic diluents.

Manufacturing concentrates are useful for shipping low melting products of this invention. Such concentrates are prepared by melting the solid products together with one percent or more of a solvent to produce a concentrate which does not solidify on cooling to the freezing point of the pure product or below.

Useful liquid concentrates include the emulsifiable concentrates, which are homogeneous liquid or paste compositions readily dispersed in water or other liquid carriers. They may consist entirely of the active compound with a liquid or solid emulsifying agent, or they may also contain a liquid carrier such as xylene, heavy aromatic naphthas, isophorone and other relatively non-volatile organic solvents. For application, these concentrates are dispersed in water or other liquid carriers and normally applied as sprays to areas to be treated.

Typical surface-active wetting, dispersing, and emulsifying agents used in agricultural formulations include, for example, the alkyl and alkylaryl sulfonates and sulfates and their sodium salts; alkylamide sulfonates, including fatty methyl taurides; alkylaryl polyether alcohols, sulfated higher alcohols; polyethylene oxides; sulfonated animal and vegetable oils; sulfonated petroleum oils; fatty acid esters of polyhydric alcohols and the ethylene oxide addition products of such esters; and the addition products of long-chain mercaptans and ethylene oxide. Many other types of useful surface-active agents are available in commerce. The surface-active agent, when used, normally comprises about 1-15% by weight of the plant growth regulator composition.

Other useful formulations include simple solutions of the active ingredient in a solvent in which it is completely soluble at the desired concentration, such as acetone or other organic solvents.

A plant growth and development modifying effective amount of said benzoxazole in a plant growth and development modifying composition diluted for application is normally in the range of about 0.004% to about 5% by weight. Many variations of spraying and dusting compositions known in the art may be used by substituting said plant growth and development modifying compounds of this invention into compositions known or apparent to the art. The plant growth and development modifying compositions of this invention may be formulated with other active ingredients, including insecticides, nematicides, acaricides, fungicides, other herbicides or plant growth regulators, fertilizers, etc.

In using the compositions to modify plant growth and development according to the method of this invention, it is only necessary that a plant growth and development modifying, or herbicidally, or plant growth regulant, effective amount of at least one of said benzoxazoles, depending on the objective, be applied to the locus where such modification, or control, or regulation is desired, generally a soil locus where agricultural crops are grown and either before or, preferably, after the plants have emerged. Liquid plant growth regulator compositions may be incorporated into the soil, applied to the soil as a drench, or sprayed on the foliage of growing plants. Solid compositions may be applied by broadcasting or in bands. For most applications, a plant growth and development modifying, or herbicidally, or plant growth regulant, effective amount will be about 0.005 to 8 kg, preferably 0.01 to 2 kg, per hectare.

The plant growth and development modifiers of this invention were investigated for activity in preemergence and postemergence tests according to the following procedure:

Flats were filled with a steam-sterilized sandy loam soil. Seeds of the following test plant species were planted in furrows: cotton (Gossypium hirsutum) or limabean (Phaseolus limensis), field corn (Zea mays L.), soybean (Glycine max), wheat (Triticum aestivum), barnyardgrass (Echinochloa crus galli), johnsongrass (Sorghum halepense), pitted morningglory (Ipomoea lacunosa), velvetleaf (Abutilon theophrasti), field bindweed (Convolvulus arvenia), and green foxtail (Setaria viridis). Soil was leveled to a 1 cm depth over the seeds.

In both the preemergence and postemergence tests the test chemicals were applied as aqueous acetone solutions at a rate equivalent to 8.0 kilograms/hectare.

A flat for premergence test was watered and the soil evenly drenched with the water-acetone solution of test chemical. The treated flat was placed in a greenhouse where it was watered regularly at the soil surface for a period of 13 days. The effect of the test chemical was then recorded. In some tests individual plant species were examined for percent kill and a vigor rating of one to five was assigned to the surviving plants, a vigor of five signifying no chemical injury. In other tests percent kill and vigor rating were combined in a single rating called "percent control," which has the following significance:

______________________________________Percent Description Effect EffectControl of Effect on Crops on Weeds______________________________________ 0 No effect No crop reduction No weed control10 Slight discoloration Very poor weed or stunting control20 Slight effect Some discoloration, Poor weed control stunting or stand loss30 Crop injury more Poor to deficient pronounced but not weed control lasting40 Moderate injury, Deficient weed crop usually control recovers50 Moderate Crop injury more Deficient to effect lasting, recovery moderate weed control60 Lasting crop Moderate weed injury no recovery control70 Heavy injury and Control somewhat stand loss less than satisfactory80 Severe Crop nearly Satisfactory to effect destroyed a few good weed control survivors90 Only occasional Very good to live plants left excellent control100 Completely Complete crop Complete weed effective destruction destruction______________________________________ Footnotes denoting other morphological responses observed were also recorded.

A flat for postemergence test was placed in a greenhouse for an 8 to 10 day growing period. The test solution was then hand-sprayed onto the foliage of the merged test plants. After spraying, the foliage of the test plants was kept dry for 24 hours after which time regular watering was resumed for a period of 13 days. The effect of the test chemical was then recorded in the same manner described for the preemergence tests.

The results of the preemergence and postemergence tests appear in Tables I and II, respectively. In the Tables, columns headed "PC," "V," "K," and "F" refer to percent control, vigor, kill, and footnotes, respectively. Footnotes B, C, D, E, G, H, J, M, P, Q, and U, defined in the Tables and described in more detail below, indicate plant growth regulator activity.

Stunting (footnote B) can retard the growth of grasses, which reduces maintenance time for lawns, golf courses, and highway rights-of-way. Stunting in fruit trees may reduce stem growth, which can reduce pruning and trimming time. Stunting in cereal and broadleaf crops such as wheat, cotton, and soybeans may result in a shorter, thicker stalk which resists lodging, in turn promoting higher yields.

Desiccation (footnote C) can reduce the pre-harvest moisture content in cereals such as wheat, or in broadleaf crops such as sunflower. Desiccation can result in the loss of foliage, and in such plants as soybeans, cotton, peanuts, and potatoes the loss of foliage aids in harvesting.

Axillary growth stimulation (footnote D), or branching, can lead to multiple stems in cereals such as wheat (tillering). An increase in the number of stems may increase the yield. In soybeans, axillary stimulation at flowering can result in more fruits, increasing yield.

Nastic response (footnote E) is manifested by twisting and bending of the plants and indicates a hormonal disruption. A natural and useful nastic response is the curling of a tendril or stem around a support, e.g., in peas and pole beans.

Stimulation (footnote G) of vegetative growth in crops such as clover results in increased yields of forage. The stimulation of reproductive growth in fruits and cereals will also result in increased yields from those crops.

Defoliation (footnote H), or loss of plant foliage just prior to harvesting crops such as soybeans, cotton, peanuts and potatoes will facilitate harvest of those crops. Foliage present at the time cotton is harvested may stain the cotton.

Intumescence (footnote J) indicates formation of abnormal swellings, a disruption of the hormonal balance that promotes normal growth. Intumescence-causing agents can promote the growth of tissue, such as tobacco callus.

Negative root geotropism (footnote M) connotes the upward growth of roots out of the soil and indicates disruption of the plant's normal hormonal balance. There can be a correlation between negative root geotropism and increase in the number of pods on soybean plants.

Deeper green lower leaves (footnote P) suggests delay of senescence, increased chlorophyll product, or chlorophyll retention. These phenomena mean greater photosynthesis, which may increase yield from plants such as soybeans.

Leaf alteration (footnote Q) indicates disruption in the plant's hormonal balance. Leaves of plants can be altered to allow better utilization of sunlight, which may enhance plant growth.

Benzoxazoles of this invention were also found in separate tests to inhibit the transport of auxin in excised stems of soybean plants, to affect geotropic response in cress (Lepidium sativum) seedlings, and to enhance pod set in soybean plants.

TABLE I Preemergence Tests Plant Cotton.sup.1 / Barngr Bindweed Corn-F Greenfox Mrnglory Johngr Lima Bean Soybean Velvetlf Wheat Ex- PC or PC or PC or PC or PC or PC or PC or PC or PC or PC or ample V K F V K F V K F V K F V K F V K F V K F V K F V K F V K F 1 4 0 BE 3 60 BE 4 0 M 4 0 B -- -- -- 4 0 BE 4 0 B 4 0 BE 3 60 BE 4 0 B E 2 4 0 I 4 0 A 3 0 ABM 4 0 B 4 0 M 4 0 AB 4 0 BM 3 0 BIM 4 0 BI 3 0 AB 3 4 0 AB 4 20 AB 4 0 ABM 4 0 ABM 4 20 A 4 0 M 4 0 BM 3 0 BM 3 50 AB 4 0 A 4 5 0 0 4 0 A 5 0 0 4 0 A 4 0 A 5 0 0 5 0 0 5 0 0 5 0 0 5 0 0 5 4 0 AM 4 25 BM 3 0 BM 3 0 ABM 4 0 BM 4 0 M 3 80 BEM 3 20 BM 4 0 BM 4 0 M 6 7 3 0 ABEI 3 60 ABE 3 0 ABM 3 0 AB 4 0 ABE 4 0 BE 3 0 ABIM 2 50 AB 4 20 AB 4 0 AE 8 4 0 M 3 30 BEI 3 0 ABM 4 0 BIM 3 40 BM 4 0 M 4 50 BM 3 30 BMP 4 0 BIM 5 0 0 9 4 0 M 3 0 ABM 4 0 0 4 0 M 4 0 BM 4 0 M 4 0 I 4 0 M 3 95 BM 4 0 A 10 5 0 0 4 0 B 4 70 B 4 50 0 4 0 B 4 20 B 4 80 B 4 20 B 4 0 B 4 0 A 11 4 0 M 4 0 AI 4 30 KM 5 0 0 4 0 M 4 0 M 4 0 BM 4 10 AEIM 5 0 0 4 0 M 12 5 0 0 5 0 0 4 30 M 5 0 0 5 0 0 5 0 0 4 70 B 4 50 0 5 0 0 5 0 0 13 4 0 AB 4 0 B 4 0 ABI 5 0 0 5 0 0 5 0 0 5 0 0 4 50 B 5 0 0 4 0 A 14 4 0 A 5 0 0 4 0 M 4 0 A 4 0 A 5 0 0 4 0 M 4 0 AM 5 0 0 4 0 A 15 5 0 0 4 10 ABI 4 0 A 4 10 A 3 20 AB 4 0 B 5 0 0 4 20 BI 4 0 B 5 0 0 16 2 30 ABE 3 40 ABE 2 0 ABE 3 40 ABE 3 0 ABE 3 0 ABE 2 80 BE 2 50 ABE 3 0 ABE 3 0 ABE 17 3 0 ABE 3 30 ABE 4 0 0 3 40 ABE 3 30 ABE 3 0 ABE 3 30 BE 2 30 BE 3 40 ABEI 3 0 ABE 18 3 0 ABNE 3 40 BE 2 0 ABE 4 0 BEI 3 0 ABEI 3 0 ABE 3 20 ABE 3 30 ABE 3 0 BEI 3 0 ABE 19 2 20 ABE 2 80 ABE 2 30 ABE 3 90 ABE 2 10 ABE 3 10 ABE 3 50 ABE 3 70 ABE 3 80 BE 3 20 ABE 20 3 0 BEP 2 30 ABE 4 30 ABE 5 0 0 3 0 ABE 3 0 M 2 30 UBE 2 50 ABE 2 40 ABE 4 0 E 21 3 50 BEP 3 10 BE 2 0 BE 3 70 B 3 20 BE 2 0 BE 2 80 ABE 2 90 BE 3 10 BE 3 0 BEP 22 3 0 ABE 3 20 ABEI 3 0 ABEI 3 0 ABE 3 30 BE 3 0 ABE 3 70 ABEI 3 20 ABD 3 0 EI 3 30 ABEM 23 3 0 E 1 90 ABE 2 0 ABE 1 95 ABE 2 50 ABE 3 0 E 3 0 ABE 2 50 ABE 0 100 0 3 0 AE 24 3 0 ABE 3 20 ABE 2 0 ABE 2 35 ABE 3 20 ABE 3 0 ABE 3 30 ABE 3 0 BEI 3 30 ABE 2 0 ABE 25 3 0 AB4E 3 50 BE 2 30 AB2E 3 20 BE 3 20 B4E 3 30 B4EI 2 20 B4E 3 0 B3E 26 5 0 0 5 0 0 5 0 0 5 0 0 5 0 0 5 0 0 4 0 B1 3 0 B1E 5 0 0 5 0 0 27 20 E 80 B 30 BEM 90 B5 30 EB 0 0 30 A 70 B5 0 E 20 EB1 28 70 B5 50 0 30 B2M 90 B5 40 BE 50 B3 50 B2G 50 B5U 0 0 30 E 29 30 B1MP 0 0 20 B2EMP 10 B2P 40 B2E 10 PE 60 B2E 70 B3E 20 B1E 50 B2E 30 10 M 10 BIE 20 MI 20 B1E 30 B2E 10 M 30 B2M 70 B5EM 30 B1EI 60 B2E 31 0 M 0 0 10 MP 0 0 0 0 40 B2M 20 B2M.sup.1 40 B3EM 0 0 20 B2E 32 3 0 AB 3 0 ABE 4 0 M 3 40 ABE 3 0 ABE 4 0 ABE 2 50 BEM 3 0 BDI 3 0 BE 3 0 ABM 33 4 0 M 4 30 BE 3 0 MP 3 60 ABEP 4 50 BEM 4 0 M 4 0 M 3 50 BEM 5 0 0 3 0 EM 34 5 0 0 3 30 BE 4 0 A 4 10 AB 4 0 BEI 5 0 0 3 80 B 4 60 B 3 90 BI 4 0 A 35 4 0 B 4 40 B 4 0 A 4 20 B 4 0 B 5 0 0 5 0 0 4 0 B 4 50 0 4 0 A 36 5 0 0 4 0 B 5 0 0 4 30 B 5 0 0 5 0 0 4 0 BM 4 0 B 4 30 B 5 0 0 37 5 0 0 5 0 0 5 0 0 5 0 0 5 0 0 5 0 0 5 0 0 5 0 0 5 0 0 5 0 0 38 5 0 0 5 0 0 5 0 0 5 0 0 5 0 0 5 0 0 5 0 0 5 0 0 5 0 0 5 0 0 39 5 0 0 5 0 0 4 0 A 5 0 0 5 0 0 5 0 0 4 0 AI 5 0 0 5 0 0 5 0 0 40 5 0 0 4 30 A 4 0 M 3 50 BEI 4 0 M 4 0 M 4 0 M 4 0 M 4 20 BM 4 0 M 41 4 0 A 5 0 0 5 0 0 4 0 A 4 0 A 5 0 0 4 0 AM 4 0 BM 5 0 0 5 0 0 42 4 0 E 4 0 E 4 0 M 3 0 BI 4 0 B 4 0 BI 4 0 B 3 0 ABDI 4 0 A 5 0 0 43 4 0 A 4 0 A 4 30 0 4 0 A 4 0 E 5 0 0 5 0 0 5 0 0 4 0 A 5 0 0 44 5 0 0 4 0 B 4 0 M 4 0 AB 4 0 BM 4 0 0 4 0 IM 4 0 M 0 100 0 4 0 M 45 5 0 0 4 30 B 4 30 0 4 0 B 4 50 0 5 0 0 5 0 0 5 0 0 5 0 0 5 0 0 46 5 0 0 5 0 0 5 0 0 5 0 0 5 0 0 5 0 0 5 0 0 4 0 B 5 0 0 5 0 0 47 5 0 0 5 0 0 4 0 M 4 0 A 5 0 0 5 0 0 4 50 BM 5 0 0 5 0 0 5 0 0 48 5 0 0 5 0 0 5 0 0 4 0 AI 4 0 I 4 0 N 5 0 0 5 0 0 5 0 0 5 0 0 49 4 0 A 5 0 0 4 0 M 4 0 A 4 0 A 4 0 A 4 0 AM 4 70 ABEM 5 0 0 4 0 AM 50 5 0 0 5 0 0 4 0 BM 5 0 0 5 0 0 5 0 0 4 10 M 4 0 B 5 0 0 4 0 B 51 3 0 ABE 3 50 ABEP 4 0 M 2 80 AB 3 10 BE 4 0 ABEP 4 0 M 3 40 ABDP 4 0 B 3 20 ABE 52 4 0 ABE 4 0 ABE 4 0 BI 5 0 0 3 0 BE 4 0 ABE 3 0 BE 3 0 BDEI 4 0 A 4 0 A 53 3 0 BEM 3 30 BEI 4 30 AIM 3 0 BE 4 20 BM 4 0 M 4 0 M 3 40 BIM 3 10 BEI 54 3 0 ABE 3 50 BE 2 30 ABE 0 100 0 3 0 BE 3 0 BE 3 50 ABE 3 50 BDE 3 0 BE 3 0 BE 55 3 0 BEP 4 0 E 4 0 BM 3 0 BEP 3 0 BE 3 0 BE 3 0 B 3 50 BEM 4 0 E 3 0 BEP 56 4 0 M 5 0 0 4 0 M 3 0 BEM 4 0 A 3 0 EM 3 0 AEI 3 20 BEM 5 0 0 4 0 M 57 3 0 AEI 3 0 EI 4 0 IM 3 0 BE 4 0 M 3 0 BE 3 20 EM 3 30 BDI 3 0 EI 3 0 AEIM 58 3 0 BEP 4 0 3 4 0 M 3 0 BEP 3 0 BE 3 0 BE 3 0 ABE 3 0 ABE 3 20 BE 3 0 BEP 59 3 0 BM 3 0 B 4 0 M 4 0 A 4 0 3 3 0 BE 5 0 0 3 0 E 4 0 E 4 0 BE 60 3 10 AB4E 3 90 BE 2 30 AB3E 3 0 AB4E 3 30 BE 3 50 B4E 3 0 B3 3 0 AB4E 3 0 BE 3 0 E 61 10 AB1 20 AB1 0 0 40 AB2E 0 0 10 AB2 0 0 0 0 0 0 0 0 62 5 0 0 5 0 0 4 0 M 5 0 0 4 0 M 5 0 0 5 0 0 5 0 0 5 0 0 5 0 0 63 60 B3EAPB5 100 0 100 0 100 0 90 BE4 90 B4EA 90 B5E 100 0 100 0 100 0 64 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 65 0 0 20 BEI 20 B2E 0 0 0 0 0 0 0 0 10 B1 0 0 40 B2E 66 0 0 0 0 0 M 0 0 0 0 0 0 0 0 0 0 0 0 10 B1M 67 0 0 0 0 30 B1A 0 0 0 0 0 0 30 B2 20 B1 0 0 60 B2E 68 4 0 M 4 0 AE 4 0 AM 4 0 BM 5 0 0 4 0 M 4 0 BEM 4 0 BM 4 0 A 4 0 AM 69 5 0 0 5 0 0 4 0 B 5 0 0 4 0 B 5 0 0 5 0 0 4 50 BEM 5 0 0 5 0 0 70 5 0 0 4 50 A 4 0 A 4 10 A 5 0 0 5 0 0 5 0 0 5 0 0 5 0 0 5 0 0 71 5 0 0 5 0 0 4 0 M 5 0 0 5 0 0 5 0 0 4 0 M 4 0 M 5 0 0 5 0 0 72 4 0 B 3 90 B 4 0 BM 4 0 B 4 0 B 4 0 B 4 0 B 3 40 B 4 60 B 4 20 BE 73 5 0 0 4 40 0 4 0 M 4 30 0 0 100 0 4 0 B 4 0 M 5 0 0 4 30 0 5 0 0 74 4 0 M 4 0 A 4 0 AM 4 0 AM 4 0 M 4 0 M 4 0 AB 3 0 B 4 20 A 4 0 AM 75 5 0 0 5 0 0 5 0 0 5 0 0 5 0 0 5 0 0 5 0 0 5 0 0 5 0 0 5 0 0 76 4 0 M 4 0 BM 4 0 M 4 0 BM 4 0 BM 4 0 M 4 20 M 4 0 BM 4 0 M 4 0 M 77 4 0 M 4 0 BEM 3 0 BM 4 0 M 3 0 BEM 4 0 M 4 0 BM 4 30 EM 4 0 M 4 0 M 78 3 0 AB 4 0 A 3 0 M 4 0 BM 4 0 M 4 0 B 4 0 AM 3 40 BM 4 20 A 4 0 AM 79 4 0 BM 3 30 EI 3 0 ABMP 4 0 M 3 40 BEM 4 0 M 3 10 BM 3 20 BMP 4 0 IM 4 0 AB 80 5 0 0 4 10 0 4 30 0 4 40 A 3 80 AB 4 0 B 5 0 0 4 20 B 5 0 0 4 0 A 81 5 0 0 5 0 0 5 0 0 4 0 A 5 0 0 5 0 0 5 0 0 5 0 0 5 0 0 5 0 0 82 4 0 BEM 3 95 B 4 0 ABM 2 95 B 3 20 BE 4 0 M 4 0 AIM 3 60 BIM 3 20 BI 4 0 AE 83 2 30 ABE 4 0 AE 2 0 ABE 3 30 ABE 3 30 ABE 3 0 ABE 0 100 0 2 70 ABE 4 40 AB 3 0 ABE 84 3 0 ABEP 3 40 ABE 4 0 ABMP 3 40 ABEP 3 20 ABE 4 0 ABEP 2 30 ABMP 3 20 ABMP 3 50 ABE 3 0 ABEP 85 3 10 BE 3 40 ABE 2 0 ABE 3 40 ABE 2 30 ABE 3 10 BE 3 20 ABE 2 70 ABE 3 50 B 3 0 BE 86 3 0 BE 3 90 BE 2 30 ABEM 2 80 BE 3 20 BE 2 0 BEP 3 10 ABEM 2 80 BE 2 90 BE 4 0 E 87 3 0 BE 3 10 BE 4 30 EM 5 0 0 3 0 BE 3 0 BE 3 0 ABEI 3 40 BD 4 0 EI 4 0 BEM 88 3 0 BE 2 40 BE 2 30 ABEK 2 0 BE 2 0 BE 3 0 BE 2 30 ABE 1 90 ABE 1 95 BE 2 0 BE 89 3 0 ABE 3 10 ABE 2 0 ABE 3 0 BE 0 100 0 3 0 ABE 3 20 ABE 3 20 BE 3 0 BE 3 0 ABE 90 3 0 AB4E 3 30 BE 2 0 AB3E 3 0 B4E 3 30 BE 3 10 AB4E 3 90 B4E 3 90 BE 3 0 AB3E 91 4 0 B1 5 0 0 4 0 B1M 5 0 0 5 0 0 4 0 B1 4 0 B1E 4 0 B1M 5 0 0 4 0 B1E 92 50 B5E 50 E 0 GMP 90 B56 40 BE 40 B5E 30 E 50 B3E 0 E 30 E 93 80 B5 70 0 50 B3M 60 B3 0 E 50 B3E 50 B3 80 B5 50 0 40 B1E 94 30 B2MP 0 0 20 MI 90 B5 90 B4AE 10 MP 80 B3EA 90 B5E 0 0 40 B2E 95 4 0 ABM 3 50 ABE 4 0 AM 3 40 AB 3 40 B 4 0 AM 3 90 B 3 50 BE 3 90 ABI 4 0 A 96 5 0 0 5 0 0 4 0 AM 5 0 0 5 0 0 5 0 0 5 0 0 4 20 B 5 0 0 5 0 0 97 30 0 90 B 40 B2MP 90 0 80 AB 50 AB2 70 0 100 0 90 BEI 40 0 98 60 B5 40 BE 40 B3EM 40 B5E 30 BE 40 B5E 40 B5E 60 B5 20 BE 40 B2E 99 10 AB2 20 AB1E 20 B1M 10 AB1 0 B1E 0 0 30 AB1 10 B2 0 0 30 B1E 100 80 B5E 60 BE 70 AB3EM 80 B5E 60 BE 80 B5E 60 B5E.sup.1 90 B4E 60 BEI 60 AB2EI 101 80 B5EP 10 B1E 30 B2EP 90 B5EA 80 B5E 80 B5E 80 B5E.sup.1 90 B5E 40 B2E 50 B2EA 102 0 0 10 AB2 70 B1K 10 B1 10 B3 10 B2M 20 AB2.sup.1 60 B2 10 B3 30 B2 103 20 AB4 0 0 10 AB1 0 0 10 B 20 AB1 0 0.sup.1 0 0 10 0 0 0 104 30 E 0 0 10 B2M 0 0 0 0 0 0 20 B2E.sup.1 10 B2M 0 0 10 B1E 105 60 B5P 10 E 30 EPMB2 30 B5 40 BE 50 0 0 0.sup.1 0 0 60 B 10 E 106 80 B5 50 BE 30 PM 40 B3 70 BE 50 B3 10 B1.sup.1 20 B3 70 BE 10 E 107 0 0 0 0 10 M 80 B3AE 20 B1EM 20 B1AM 10 B1M.sup.1 60 B3M 0 0 30 B2M 108 20 B1E 0 0 30 B2EM 80 B5E 30 B1E1 20 PEM 90 B3EMA.sup.1 60 B3PEM 10 L 20 EM FOOTNOTES V = Vigor 5 = Plants normal 4 = Slight injury; plants will or have already recovered 3 = Moderate injury; plants expected to recover 2 = Moderate to severe injury; plants are not expected to recover 1 = Severe injury; plants will not recover 0 = Dead plant K = % Kill F = Footnote: A = Necrosis B = Stunted C = Desiccation D = Axillary Growth Stimulation E = Nastic Responses F = Necrotic Spots G = Growth Stimulation H = Defoliant I = Chlorosis J = Intumescence K = Suspected germination failure L = Stand may be affected by nonchemical factors M = Negative root geotropism N = Bleaching P = Deeper green lower leaves Q = Leaf alterations U = Any other morphological response Subfootnotes: 1 = 0%-24% 2 = 25%-49% 3 = 50%-74% 4 = 75%-100% 5 = refers to stunting only 75%-100% stunted with 0-30% phytotoxicity .sup.1 Data for cotton TABLE II__________________________________________________________________________Postemergence Tests Plant__________________________________________________________________________Barngr Bindweed Corn-F Greenfox MrngloryPC or PC or PC or PC or PC orExample V K F V K F V K F V K F V K F__________________________________________________________________________1 4 0 0 4 0 B 5 0 0 4 0 A 4 0 AB2 4 0 C 4 0 AB 4 0 M 4 0 A 4 0 AB3 4 0 C 4 0 C 4 0 C 4 0 C 4 0 C4 4 0 A 3 80 A 4 0 A 4 0 A 5 0 05 5 0 0 5 0 0 5 0 0 5 0 0 5 0 07 4 0 CM 3 0 C 4 0 M 4 0 BC 4 0 CM8 4 0 AM 3 0 E 4 0 M 4 0 3 3 0 BE9 4 0 C 4 90 CI 4 0 CM 5 0 0 4 0 CI10 5 0 0 3 95 AB 5 0 0 5 0 0 4 0 A11 4 0 C 0 100 0 4 0 CM 4 0 CIM 4 0 CM12 4 0 C 3 30 BCM 5 0 0 4 0 C 4 0 C13 4 0 A 4 0 A 4 0 A 4 0 AB 5 0 014 4 0 C 3 0 CI 4 0 C 4 0 C 4 0 C15 3 0 A 3 0 AE 4 0 AM 5 0 0 4 0 AE16 3 0 A 3 20 ABE 3 0 AM 4 0 A 3 0 BE17 3 0 A 2 0 ABE 4 0 AM 4 0 A 3 0 AE18 4 10 C 3 30 BDE 3 0 BCM 5 0 0 3 40 BCEH19 3 0 BCE 3 95 BC 2 0 BCEM 3 0 BCE 3 0 BCEI20 3 0 BCE 3 60 BCE 3 0 CEM 4 20 C 2 50 BCE21 3 0 BCE 2 80 BCE 3 0 BCEM 4 0 CE 2 60 BCE22 4 0 AB 3 0 E 4 0 M 4 0 M 3 0 ABE23 3 0 BCE 0 100 0 3 0 CEM 3 10 BCE 3 95 BCE24 4 0 C 3 0 CE 2 0 BCEM 3 0 CL 2 0 BCE25 4 0 M 4 0 B1E 4 0 MEP 4 0 M 4 0 B1E26 5 0 0 5 0 0 3 0 M 5 0 0 5 0 027 40 AE 80 BE 40 B3 0 0 60 EIB28 20 AM 20 AB4E 20 AB2M 10 A 70 AB2E29 20 A 40 E 0 M 0 0 30 ABE30 40 AB4 20 ABE 30 AEM 60 A 40 ADE31 0 0 0 0 0 M 0 0 0 032 4 0 AM 3 30 BE 4 0 AM 3 0 ABM 4 0 AE33 3 0 BC 3 50 CE 4 0 BM 4 0 CE 3 0 BCEM34 4 0 A 3 50 ABM 5 0 0 5 0 0 4 0 A35 4 0 A 3 30 AI 4 0 A 4 30 A 4 0 A36 4 0 A 5 0 0 4 0 A 5 0 0 5 0 037 5 0 0 2 30 AB 4 0 AB 4 0 A 5 0 038 4 0 C 4 0 C 4 0 C 4 0 C 4 0 C39 4 0 A 4 0 A 4 0 A 4 0 AB 4 0 AI40 4 0 A 4 50 A 4 0 A 4 0 A 5 0 041 4 0 A 4 0 B 4 0 A 4 0 A 4 0 BM42 5 0 0 4 0 EI 4 0 C 3 40 BC 4 0 EM43 4 0 A 0 100 0 4 0 A 4 0 A 4 0 ADI44 4 0 A 4 0 AI 4 0 A 4 0 A 5 0 045 5 0 0 4 0 A 5 0 0 5 0 0 5 0 046 4 0 A 4 0 AI 4 0 B 4 0 A 4 0 A47 4 0 C 4 0 C 5 0 0 4 0 C 4 0 C48 4 0 A 3 20 A 4 0 A 4 0 A 4 0 AI49 4 0 C 3 40 C 4 0 CM 3 80 BC 3 0 BDIM50 4 0 A 5 0 0 5 0 0 5 0 0 5 0 051 4 0 A 4 0 ABE 4 0 A 4 0 A 3 0 ABE52 4 0 AM 3 50 BE 4 0 A 0 100 0 3 0 EM53 5 0 0 5 0 0 5 0 0 5 0 0 4 0 AB54 3 0 ABEM 2 0 BE 2 0 ABEM 3 0 BE 2 0 BEM55 3 0 AB 3 0 E 4 0 BM 3 0 ABI 3 0 AEI56 4 0 BC 3 0 BE 4 0 CM 4 0 BC 3 25 BCE57 4 0 A 3 0 E 4 0 AM 3 0 ABE 3 0 BE58 3 0 BCM 2 90 BCI 2 30 BCE 3 0 BC 3 30 BCEI59 4 0 A 3 30 AE 3 0 ABEM 3 40 AB 3 0 AB60 4 0 PM 4 0 B1E 4 0 PEM 5 0 0 4 0 B1E61 0 0 10 E 0 M 30 B3EAP 10 EB162 5 0 0 5 0 0 5 0 0 5 0 0 5 0 063 40 AE 80 BE 40 B3 0 0 60 EIB64 30 AB1 20 A 20 AB1 10 A 30 AB1E65 20 A 40 E 20 AB1M 0 0 30 ABE66 0 0 60 B 10 M 60 B2 90 BE67 0 0 0 0 0 0 0 0 0 068 4 0 A 3 0 ABE 4 0 AM 4 0 A 4 0 BE69 4 0 A 4 0 AI 4 0 A 4 0 A 4 0 B70 4 0 A 4 0 A 4 0 A 4 0 A 5 0 071 5 0 0 4 0 CI 4 0 C 3 20 BC 5 0 072 5 0 0 4 0 0 5 0 0 5 0 0 5 0 073 4 0 C 1 90 B 4 0 B 4 0 C 5 0 074 4 0 C 3 40 C 4 0 C 3 30 BC 4 0 C75 4 0 A 4 0 A 4 0 A 4 0 A 4 0 A76 4 0 M 4 0 M 5 0 0 4 0 M 4 0 M77 4 0 BC 3 20 C 4 0 M 5 0 0 4 0 BC78 4 0 C 3 0 CE 4 0 CM 3 0 BC 4 0 CM79 3 0 ABE 3 0 E 3 0 ABE 3 0 ABN 3 0 ABE80 5 0 0 0 100 0 5 0 0 3 30 C 4 0 C81 5 0 0 3 40 A 4 0 A 4 20 A 5 0 082 4 0 A 4 0 AB 4 0 A 4 0 A 4 0 ABE83 3 0 AB 2 90 ABE 3 0 AM 4 0 AB 3 0 ABE84 4 0 A 4 0 E 4 0 A 4 0 A 3 0 AE85 3 0 BCE 2 30 BCE 2 0 BCEM 3 0 BCE 3 0 BCEI86 3 0 BC 0 100 0 3 0 BCM 4 0 M 2 80 BCE87 4 0 C 3 0 BCE 3 0 BCEM 3 0 BE 3 40 BCEHPM88 3 0 BC 0 100 0 3 0 BCEM 3 0 BC 0 100 089 4 0 BC 3 50 BCE 3 0 BCEM 3 20 BCL 2 0 BCE90 5 0 0 3 0 EB1 3 0 ME 3 0 M 3 0 B1E91 3 0 MI 5 0 0 4 0 M 3 0 EM92 30 B1C2M 20 B2C1E 20 B1C1 20 B2C1U 80 B3C3E93 20 AM 10 B 20 AB1M 20 A 80 AB3E94 0 0 30 E 0 M 0 0 30 ABE95 4 0 A 3 20 A 4 0 AM 4 0 A 3 0 ABM96 5 0 0 5 0 0 4 0 A 3 0 AB 5 0 097 0 0 0 0 0 M ND ND 20 AEB198 20 AB1U 10 AB2E 40 AB2EM 30 AB2U 10 AB4PEM99 0 0 10 3 10 MI 10 ME 30 B1EM100 20 AB1 0 0 30 E 20 AB1 0 AB1E101 0 0 30 E 30 AM 50 AB2E 30 E102 0 0 0 0 0 0 0 0 0 0103 0 0 0 0 0 0 0 0 0 0104 30 AB1 20 E 20 AB1M 10 A 20 AB1E105 70 L 70 BE 30 B2M 40 B1 40 BE106 20 B5 40 BE 30 B5M 20 B2E 30 BE107 20 A 30 EI 40 AB1IM 10 E 30 BE108 40 L 40 E 30 AEM 20 E 30 BE__________________________________________________________________________ Cotton.sup.1 /Johngr Lima Bean Soybean Velvetlf WheatPC or PC or PC or PC or PC orExample V K F V K F V K F V K F V K F__________________________________________________________________________1 4 0 B 4 0 DEB 4 0 ABD 4 0 B 4 0 02 4 0 B 4 0 ABD 4 0 ABD 4 0 AB 5 0 03 4 0 C 4 0 C 4 0 C 4 0 BCI 4 0 C4 4 0 A 5 0 0 5 0 0 4 0 A 4 0 A5 5 0 0 5 0 0 5 0 0 5 0 0 5 0 07 4 0 C 4 0 CDM 3 0 CDIM 3 0 CE 3 0 C8 4 0 AM 3 0 AEM 3 0 ABD 3 0 E 4 0 E9 4 0 C 4 20 CI 4 0 CIM 4 90 C 4 0 C10 5 0 0 4 0 A 4 0 A 4 0 AB 5 0 011 4 0 C 3 0 CM 4 0 CEIM 0 100 0 4 0 CM12 5 0 0 5 0 0 4 0 C 5 0 0 4 0 C13 4 0 A 5 0 0 5 0 0 5 0 0 4 0 A14 4 0 C 4 30 CI 3 0 BCDI 4 20 C 4 0 C15 3 10 A 3 0 ABDE 3 0 ABD 4 0 AB 3 0 A16 4 0 A 3 0 ABD 4 0 ABD 3 20 BE 4 0 A17 4 0 A 2 0 BED 3 0 ABD 2 20 ABE 4 0 A18 4 10 C 3 0 BCE 3 0 BCDEP 3 0 E 4 0 BC19 3 0 BCE 2 0 BCE 3 0 BCD 3 90 BCE 3 0 BC20 3 20 C 2 30 BCM 2 0 BCDE 3 40 BCE 4 0 M21 4 0 BCE 2 50 BCM 2 0 BCDM 2 90 BCE 4 0 CEM22 4 0 A 3 0 H 3 0 ABDE 3 0 AE 5 0 023 3 10 BCE 0 100 0 2 30 BCDM 0 100 0 3 0 CE24 3 10 CE 3 0 CE 3 0 BCD 3 0 BCE 5 0 025 4 0 PM 3 0 B3E 3 0 BAP 4 0 B1E 4 0 B1E26 5 0 0 5 0 0 3 0 DEC3 5 0 0 5 0 027 40 E 40 E 50 B5EID 50 BE 20 E28 20 AB1M 80 AB2H3 10 AB3DP 60 AB2E 10 A29 40 AB3 30 AE 50 AB3DE 30 E 10 I30 50 L 30 AB4 30 AB5I 40 AE 50 AN31 0 0 0 0 40 B5ED 0 0 30 AB132 4 20 AM 2 0 BEM 3 0 BDIM 3 0 BEM 4 0 AM33 4 0 CE 3 0 BEM 2 0 BCD 3 0 BCEI 3 0 BCEM34 3 0 A 4 0 AD 4 0 AM 2 90 BM 3 0 AM35 4 0 A 4 0 A 4 0 A 3 0 AB 4 0 A36 5 0 0 3 0 ABD 3 0 ABD 3 50 AB 4 0 A37 4 0 AB 3 0 ABDE 4 0 BD 5 0 0 5 0 038 4 0 C 4 0 CI 4 0 CI 4 0 C 4 0 C39 4 0 A 4 0 A 4 0 I 4 10 A 4 0 A40 4 30 AB 4 0 BDI 4 0 ADI 4 0 A 5 0 041 3 50 AB 4 0 AI 4 0 A 4 0 B 5 0 042 4 0 C 4 0 CPM 3 0 BCDI 4 0 C 3 0 C43 0 100 0 4 0 A 4 0 ADI 5 0 0 4 0 A44 4 0 AB 4 0 AI 4 50 BI 4 0 AI 3 0 C45 3 30 A 4 0 A 5 0 0 5 0 0 4 0 A46 5 0 0 5 0 0 4 0 AI 4 0 I 4 0 A47 5 0 0 3 0 C 4 0 CM 4 0 C 5 0 048 4 0 A 4 0 I 5 0 0 3 30 AB 4 0 A49 4 20 BCM 4 0 CIM 4 0 CDIM 3 30 C 4 0 CM50 5 0 0 4 0 A 4 0 AD 4 0 A 4 0 A51 4 0 A 4 0 BDEI 3 0 ABD 3 0 ABE 4 0 A52 3 20 AB 2 0 BED 3 0 BD 3 0 BE 4 0 AM53 5 0 0 4 0 A 4 0 AEI 4 0 I 5 0 054 3 0 ABEM 2 0 BEM 3 0 ABD 2 0 BEM 4 0 AE55 3 0 ABM 3 0 EM 2 0 ABD 3 0 E 4 0 A56 3 0 BCM 2 0 BEM 2 0 BCD 2 30 BCDI 4 0 M57 4 0 A 3 0 H 3 0 BDEI 3 0 E 5 0 058 3 20 BCM 2 0 BCEI 3 0 BCD 0 100 0 3 0 C59 3 20 AB 3 0 AE 3 0 ABD 3 70 ABE 4 0 A60 4 0 PEM 3 0 B2E 4 0 B4P 4 0 E 4 0 P61 20 B2EP 20 B2E 60 B6PDEM 10 ED1 0 M62 5 0 0 5 0 0 5 0 0 5 0 0 5 0 063 40 E 40 E 50 B6EID 50 BE 20 E64 20 AB1 20 AB1 10 B2DP 30 AB2E 30 A65 40 AB3E 20 E 50 AB3DE 30 E 10 I66 0 0 0 0 40 B5ED 10 BE 0 067 0 0 0 0 40 AB2DEIP 0 0 20 E68 4 0 AM 4 0 BDE 4 0 ABD 3 0 ABE 4 0 A69 4 0 A 5 0 0 3 0 ABDI 4 0 A 5 0 070 4 0 A 5 0 0 4 0 A 4 0 I 2 0 A71 4 0 C 4 0 C 4 0 C 5 0 0 5 0 072 5 0 0 4 0 ABD 4 0 ABD 4 0 BE 5 0 073 3 30 BC 4 0 BCD 4 0 BCD 3 0 BC 4 0 C74 4 20 C 4 0 CD 4 0 CDI 3 40 BC 4 0 C75 4 0 A 5 0 0 4 0 A 4 0 A 4 0 A76 4 0 M 5 0 0 4 0 M 3 70 AM 4 0 M77 4 0 C 4 0 CM 4 0 CDIM 3 30 BCM 3 0 M78 4 0 CM 4 0 CD 4 0 BCDM 3 0 CE 4 0 C79 3 0 ABE 4 0 AEM 3 0 ABD 3 0 EN 4 0 AEM80 5 0 0 4 0 C 4 0 C 3 30 BC 4 0 C81 4 20 A 5 0 0 5 0 0 5 0 0 5 0 082 4 20 A 4 0 D 4 0 ADI 4 0 ABE 5 0 083 3 0 AB 3 0 ABD 3 0 ABD 3 0 ABE 4 0 A84 4 0 A 3 0 BDEI 4 0 D 3 0 AEI 4 0 A85 3 0 BCE 2 0 BE 3 0 BCD 2 0 BCE 3 0 CE86 3 20 BCM 3 40 BCI 3 30 BCD 2 50 BCE 4 0 M87 4 0 C 3 0 BEH 3 0 BCDEIP 3 0 BCE 4 0 C88 3 10 BC 0 100 0 2 20 BCD 0 100 0 4 0 C89 3 0 BC 3 0 CE 3 0 BCD 2 0 BCE 4 0 C90 5 0 0 3 0 B4H 4 0 B4M 3 0 B1E 4 0 E91 3 0 M 3 0 E 3 0 B4M 4 0 MI92 20 C1M 30 B2C1 40 B3C2DEP 30 B2C1E 20 C193 20 AM 30 AB2 20 AB4DP 70 AB2E 20 A94 0 0 30 AE 50 AB3DEP 30 E 10 AE95 3 20 AM 4 0 AM 4 0 ADM 2 80 ABI 3 0 A96 5 0 0 4 0 A 5 0 0 3 0 AB 5 0 097 10 A 70 0 B3EAH2 50 B3AE 10 E 0 098 60 AB3EPU 90 AB4U 20 AB5DPU 10 AB3EM 50 AB1EM99 10 ME 10 E 10 PDIAE 20 B1EM 10 M100 20 AB1M 30 E.sup.1 20 B1D 30 E 20 A101 40 AB3 40 AE.sup.1 50 B5DE 30 E 40 A102 0 0 0 0.sup.1 0 0 0 0 0 0103 0 0 0 0.sup.1 0 0 0 0 0 0104 10 A 0 0.sup.1 10 AB1 20 B2E 20 A105 60 L 70 H1.sup.1 50 EFMB5P 100 0 10 I106 10 B3 50 H3B5.sup.1 40 B5EUPD 40 BE 10 B1107 30 AB1M 40 AB1IM.sup.1 60 B3I 20 BE 10 0108 40 B2E 30 B1EI 40 AB3DEM 60 BEI 10 EM__________________________________________________________________________ FOOTNOTES The footnotes in Table I are also applicable in Table II.

Claims

1. Plant growth and development modifying 2-(2-oxycarbonylphenyl)benzoxazoles of the formula ##STR5## wherein U is --OZ, and Z is selected from -phenyl; -phenyl carrying 1 or 2 substituents independently selected from -halogen, -lower haloalkyl, and -acetamido; -naphthyl;

V is -hydrogen; and

W is selected from -hydrogen, -lower alkyl and an agriculturally acceptable cation.

2. A compound of claim 1 selected from agriculturally acceptable cation salts of 2-(2-carboxyphenyl)-6-(2-chloro-4-trifluoromethylphenoxy)benzoxazole.

3. 2-(2-Carboxyphenyl)-6-(2-chloro-4-trifluoromethylphenoxy)benzoxazole.

4. 2-(2-Carboxyphenyl)-5-phenoxybenzoxazole.

5. A plant growth and development modifying composition comprising in admixture with an agriculturally acceptable carrier a plant growth and development modifying effective amount of 2-(2-carboxyphenyl)-6-(2-chloro-4-trifluoromethylphenoxy)benzoxazole.

6. A plant growth and development modifying composition comprising in admixture with an agriculturally acceptable carrier a plant growth and development modifying effective amount of 2-(2-carboxyphenyl)-5-phenoxybenzoxazole.

7. A plant growth and development modifying composition comprising in admixture with an agriculturally acceptable carrier an agriculturally acceptable cation salt of 2-(2-carboxyphenyl)-6-(2-chloro-4-trifluoromethylphenoxy)benzoxazole.

8. A method of modifying the growth and development of plants which comprises applying to the locus where such modification is desired a plant growth and development modifying effective amount of at least one 2-(2-oxycarbonylphenyl)benzoxazole of the formula ##STR6## wherein U is selected from -hydrogen, -lower alkyl, -lower alkenyl, -phenylmethyl, -phenyl, -phenylcarbonyl, -halophenylcarbonyl, -phenylthio, -phenylsulfoxy, -phenylsulfonyl, and --OZ in which Z is -aryl or -aryl carrying 1 or 2 substituents independently selected from -halogen, -lower alkyl, -lower haloalkyl, -lower alkoxy, -acetamido, and -phenyl; wherein aryl denotes phenyl or naphthyl;

V is selected from -hydrogen, -lower alkyl, or U and V taken together are --C.sub.4 H.sub.4 -- joining adjacent ring positions, with the proviso that V is not -hydrogen or -lower alkyl unless U is other than -hydrogen and -lower alkyl; and

W is selected from -hydrogen, -lower alkyl and an agriculturally acceptable cation.

9. A method according to claim 8 wherein said 2-(2-oxycarbonylphenyl)benzoxazole is selected from 2-(2-carboxyphenyl)-6-phenoxybenzoxazole; 2-(2-carboxyphenyl)-6-(4-chlorophenoxy)benzoxazole; 2-(2-carboxyphenyl)-6-(2,4-dichlorophenoxy)benzoxazole; 2-(2-carboxyphenyl)-6-(2-chloro-4-trifluoromethylphenoxy)benzoxazole; 2-(2-carboxyphenyl)-6-phenylbenzoxazole; 2-(2-carboxyphenyl)-5-phenoxybenzoxazole; 2-(2-carboxyphenyl)-6-(4-methylphenoxy)benzoxazole; 2-(2-carboxyphenyl)-6-(phenylsulfinyl)benzoxazole; 2-(2-carboxyphenyl)-6-(4-acetamidophenoxy)benzoxazole; 2-(2-carboxyphenyl)-6-(2,2-dimethyl-7-benzofuranoxy)benzoxazole; 2-(2-carboxyphenyl)-naphtho[2,1-]oxazole; 2-(2-carbomethoxyphenyl)-6-phenoxybenzoxazole; 2-(2-carbomethoxyphenyl)-6-(.alpha.-naphthoxy)benzoxazole; and agriculturally acceptable cation salts of 2-(2-carboxyphenyl)-6-(2,4-dichlorophenoxy)benzoxazole, 2-(2-carboxyphenyl)-6-(2-chloro-4-trifluoromethylphenoxy)benzoxazole, and 2-(2-carboxyphenyl)-6-(4-methylphenoxy)benzoxazole.

10. A method according to claim 8 wherein said 2-(2-carboxyphenyl)benzoxazole is 2-(2-carboxyphenyl)-6-phenylbenzoxazole.

11. A method according to claim 8 wherein said 2-(2-oxycarbonylphenyl)benzoxazole is 2-(2-carboxyphenyl)-6-(2-chloro-4-trifluoromethylphenoxy)benzoxazole.

12. A method according to claim 8 wherein said 2-(2-oxycarbonylphenyl)benzoxazole is 2-(2-carboxyphenyl)-5-phenoxybenzoxazole.

13. A method according to claim 8 wherein said 2-(2-oxycarbonylphenyl)benzoxazole is selected from agriculturally acceptable cation salts of 2-(2-carboxyphenyl)-6-(2-chloro-4-trifluoromethylphenoxy)benzoxazole.

14. A method of controlling the growth of plants which comprises applying to the locus where control is desired a herbically effective amount of at least one 2-(2-oxycarbonylphenyl)benzoxazole selected from 2-(2-carboxyphenyl)-6-phenoxybenzoxazole; 2-(2-carboxyphenyl)-6-(4-chlorophenoxy)benzoxazole; 2-(2-carboxyphenyl)-6-(2,4-dichlorophenoxy)benzoxazole; 2-(2-carboxyphenyl)-6-(2-chloro-4-trifluoromethylphenoxy)benzoxazole; and agriculturally acceptable cation salts of 2-(2-carboxyphenyl)-6-(2,4-dichlorophenoxy)benzoxazole, 2-(2-carboxyphenyl)-6-(2-chloro-4-trifluoromethylphenoxy)benzoxazole, and 2-(2-carboxyphenyl)-6-(4-methylphenoxy)benzoxazole.

15. A method according to claim 14 wherein said 2-(2-oxycarbonylphenyl)benzoxazole is selected from agriculturally acceptable cation salts of 2-(2-carboxyphenyl)-6-(2-chloro-4-trifluoromethylphenoxy)benzoxazole.

16. A method of regulating the growth of plants which comprises applying to the locus where regulation is desired a plant growth regulant effective amount of at least one 2-(2-oxycarbonylphenyl)benzoxazole selected from 2-(2-carboxyphenyl)-6-phenylbenzoxazole; 2-(2-carboxyphenyl)-5-phenoxybenzoxazole; 2-(2-carboxyphenyl)-6-phenoxybenzoxazole; 2-(2-carboxyphenyl)-6-(2-chloro-4-trifluoromethylphenoxy)benzoxazole; 2-(2-carboxyphenyl)-6-(4-methylphenoxy)benzoxazole; 2-(2-carboxyphenyl)-6-(phenylsulfinyl)benzoxazole; 2-(2-carboxyphenyl)-6-(4-acetamidophenoxy)benzoxazole; 2-(2-carboxyphenyl)-6-(2,2-dimethyl-7-benzofuranoxy)benzoxazole; 2-(2-carboxyphenyl)-naphtho[2,1-d]-oxazole; 2-(2-carbomethoxyphenyl)-6-phenoxybenzoxazole; 2-(2-carbomethoxyphenyl)-6-(.alpha.-naphthoxy)benzoxazole; and agriculturally acceptable cation salts of 2-(2-carboxyphenyl)-6-(2-chloro-4-trifluoromethylphenoxy)benzoxazole.

17. A method according to claim 16 wherein said 2-(2-oxycarbonylphenyl)benzoxazole is selected from 2-(2-carboxyphenyl)-6-phenylbenzoxazole, 2-(2-carboxyphenyl)-6-(2-chloro-4-trifluoromethylphenoxy)benzoxazole, and 2-(2-carboxyphenyl)-5-phenoxybenzoxazole.

18. A method according to claim 16 wherein said 2-(2-oxycarbonylphenyl)benzoxazole is 2-(2-carboxyphenyl)-5-phenoxybenzoxazole.