GB1595261A - Method of regulating the growth of aquatic weeds with pyridine derivatives - Google Patents

Description

(54) METHOD OF REGULATING THE GROWTH OF AQUATIC WEEDS WITH PYRIDINE DERIVATIVES (71) We, ELI LILLY AND COMPANY, a corporation of the State of Indiana, United States of America, having a principal place of business at 307 East McCarty Street, City of Indianapolis, State of Indiana, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention provides methods and compositions for inhibiting the growth of aquatic weeds which comprises the use of a 3-substituted pyridinemethane, pyridinemethanol, or derivative thereof, in a body of water containing the aquatic weeds to be regulated, in quantities sufficient to inhibit the growth of the said aquatic weeds. Particularly important compositions are those comprising the compounds in the form of an invert or water-in-oil emulsion.

The problems of controlling or regulating the growth of organisms in aqueous systems are serious and growing in severity. Submerged aquatic weeds, for example, cause major problems in water distribution and irrigation systems. Large sums are spent in the mechanical and other methods of removal of weed growths from irrigation canals and other bodies of water. Because of the great difficulties involved in the mechanical removal of weeds from water, it has been proposed to utilize chemical control. Accordingly, various types of chemicals have been added to such bodies of water.

However, chemicals which kill weeds create a serious problem. Masses of dead and rotting aquatic weeds result when weeds are killed, and the decomposition of the weeds decreases the amount of available oxygen in the water, makes purification of the water much more difficult, and gives off an unpleasant odor when it collects in a body of water. Thus, control of the amount of growth, rather than destruction of the aquatic weeds, would be advantageous.

In the prior art, Krumkalns et al., U.S. Patent No. 3,655,359 (April 11,1972), teach the use of substituted 3-pyridylmethanes for eliminating germinating weed grasses and broadleaf weeds selectively from crop plants such as corn, cotton, and soybeans, and their close relatives in the plant kingdom.

Also in the prior art, Krumkalns et al., U.S. Patent No. 3,744,988 (July 10, 1973), teach the use of substituted 3-pyridylmethanes for inhibiting sucker growth of tobacco plants.

Van Heyningen, U.S. Patent No. 3,396,224 (August 6, 1968), teaches a method of controlling fungi pathogenicto plants by contacting the fungus-susceptible plant with a fungicidal amount of a 3-pyridylmethane derivative, particularly a 3pyridinemethanol.

Van Heyningen et al., U.S. Patent No. 3,397,273 (August 13, 1968), teach a method for protecting plant from attack by phytopathogenic fungi by treating the plants with a fungicidally-effective amount of a 3-pyridylmethane.

Krumkalns, U.S. Patent No. 3,335,148 (August 8, 1967), discloses the 9-(3 pyridyl) derivative of fluorene, 9-fluorenol, xanthene and 9-xanthenol, and the nonphytotoxic acid addition salts thereof. The compounds are alleged to possess antifungal and antibacterial activities.

Another reference, Krumkalns, U.S. Patent No. 3,361,753 (January 2, 1968), is directed to 9-(3-pyridyl)-thioxanthene and thioxanthol derivatives, active as plant antifungal agents and as antibacterial agents.

Another reference is German Patent No. 1,935,292, also identified by Derwent No. 04548S, which patent teaches and claims a means for restraining growth and influencing the habits of higher plants, influencing blossom and fruit formation, checking the growth of grass, and the like, using triarymethylimidazoles, -pyrazoles, and -triazoLes, or their salts. One of the aryl groups is taught as pyridyl.

The reference does not include use on aquatic weeds or plants.

This invention provides a novel method and compositions for inhibiting the growth of aquatic weeds which comprises adding to the water containing said weeds a growth-regulating and non-herbicidal amount of a compound of the formula

wherein X is hydrogen, hydroxyl, halo, C1-C3 alkoxy, C1-C6 alkylthio, cyclohexylthio, 4-chlorophenylthio, -N(R3)2, acetamido, imidazol- I -yl, morpholino, or cyano; R1 is hydrogen, C1Cg alkyl, ethynyl, C3-C6 cycloalkyl, benzyl, phenyl, or monohalophenyl; R2 is C1-C9 alkyl, C3-C6 cycloalkyl, cyclohexylmethyl, cyclohexylethyl, phenyl, monohalophenyl, dihalophenyl, 3,4-(methylenedioxy)phenyl, trifluoromethylphenyl, p-cumenyl, tolyl, phenoxyphenyl, phenoxy(C1-C4)alkyl, benzyl, C1-C4 alkoxyphenyl, pentafluorophenyl, xylyl, 2-thienyl, 3-pyridyl, 1,3 dioxan-5.yI or 5-methyl-l,3-dioxan-5-yl; R1 and R2, when taken together with the carbon atom to which they are attached, form 2,6-dimethylcyclohexan- 1 -yl, 9-fluorenyl, 10,I l-dihydro-SH- dibenzo[a,d]cyclohepten-5-yl, 9-xanthenyl, SH-dibenzo[a,d]cyclohepten-5-yl, or 9 thioxanthenyl; R3 is hydrogen or C1-C6 alkyl; and the nonphytotoxic acid addition salts thereof.

In the above formula, C1C3 alkoxy can be methoxy, ethoxy, isopropoxy, and propoxy.

The C1-C9 alkyl groups are saturated straight or branched-chain alkyl and can be illustratively methyl, ethyl, propyl, isopropyl, n-butyl, s-butyl, t-butyl, namyl isoamyl, s-amyl, n-hexyl, isohexyl, s-hexyl, n-heptyl, isoheptyl, s-heptyl, n octyl, isooctyl, s-octyl, n-nonyl, isononyl, and s-nonyl.

C3-C6 Cycloalkyl can be, illustratively, saturated monocyclic cycloalkyl such as cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl.

Monohalophenyl can be, illustratively, o-chlorophenyl, p-chlorophenyl, p fluorophenyl, p-bromophenyl, p-iodophenyl and m-chlorophenyl.

Dihalophenyl can be, for example, 2,4-difluorophenyl, 2,4-dichlorophenyl, 2,4-dibromophenyl, 3,4-difluorophenyl, 3,4-dichlorophenyl, 3,4-dibromophenyl, 4chloro-3-fluorophenyl, 3,5-difluorophenyl, 3,5-dichlorophenyl and 3,5dibromophenyl, C1-C8 Alkylthio, is methylthio, ethylthio, propylthio, isobutylthio, hexylthio and similar groups.

Phenoxy(C1-C4)alkyl can be groups such as phenoxymethyl, phenoxyethyl, phenoxypropyl, and phenoxybutyl.

C1-C4 Alkoxyphenyl can be, for example, methoxyphenyl, ethoxyphenyl, propoxyphenyl and butoxyphenyl.

Xylyl is 3,4-xylyl, 2,3-xylyl, 2,4-xylyl, 3,5-xylyl, 2,5-xylyl or 2,6-xylyl.

Halo or halogen is chlorine, bromine, iodine, or fluorine.

The compounds of Formula l are effective for inhibiting the growth of aquatic weeds when applied to the water in which the weeds live in a concentration in the range of from 0.25 to 10 ppm. by weight, suitably at a concentration in the range of from 0.25 to 2 ppm.

The preferred compounds of Formula I are those wherein X is hydrogen, hydroxyl, or methoxy; R1 is hydrogen, C1-C8 alkyl, C-C6 cycloalkyl, or phenyl; R2 is C1-C,, alkyl, cyclohexylmethyl, cyclohexyl, phenyl, 4-fluorophenyl, 4chlorophenyl, 4-methoxyphenyl, p-tolyl, or 4-phenoxy-n-butvl: R1 and R2, when taken together with the carbon atom to which they are attached, form 9-fluorenyl, 9-xanthenyl, or 10,1 l-dihydro-5H- dibenzo[a,d]cyclohepten-5-yl; and the nonphytotoxic acid addition salts thereof.

The compounds more preferred are those of Formula I above wherein X is hydrogen, hydroxyl or methoxy; R7 is C3-C8 alkyl, cyclopropyl, cyclohexyl, or phenyl; R2 is C4-C7 alkyl, 4-chlorophenyl, 4-fluorophenyl, 4-methoxyphenyl, p-tolyl, cyclohexylmethyl, phenyl, or 4-phenyoxy-n-butyl; R' and R2, when taken together with the carbon to which they are attached, form 9-fluorenyl; and the nonphytotoxic acid addition salts thereof.

The compounds most preferred are those of Formula I above wherein X is hydroxyl; R' is isopropyl, cyclopropyl, t-butyl, isobutyl or phenyl R2 is n-hexyl, phenyl, 4-fluorophenyl, 4-methoxyphenyl, or 4-chlorophenyl; and the nonphytotoxic acid addition salts thereof.

The most preferred compounds are a - (4 - chlorophenyl) - a - isopropyl 3 - pyridinemethanol, cr- isopropyl - a - (4 - methoxyphenyl)- 3 pyridinemethanol, and a - (t - butyl) - a - (4 - fluorophenyl) - 3 pyridinemethanol.

The compounds of Formula I are conveniently prepared by methods wellknown to the art. Thus, many of the 3-pyridinemethanols and derivatives thereof are described by Van Heyningen, U.S. 3,396,224 (August 6, 1968); and many of the 3-pyridinemethane derivatives are disclosed by Van Heyningen et al., U.S.

3,397,273 (August 13, 1968). The 9-(3-pyridyl) derivatives of fluorene, 9-fluorenol, xanthene, and 9-xanthenol, and methods for their preparation, are disclosed by Krumkalns, U.S. 3,335,148 (August 8, 1967); while the 9-(3-pyridyl)thioxanthene and thioxanthenol derivatives, together with methods for their preparation, are taught by Krumkalns, U.S. 3,361,753 (January 2, 1968). The compounds of the generic formula wherein X=phenylthio or N,N-dialkyl, and methods for their preparation are disclosed by Krumkalns et al., U.S. 3,849,423 (November 19, 1974).

In particular, the a,a-dialkyl-substituted 3-pyridinemethanols are prepared according to the teaching of Wibaut et al., Rec. Trav. Chim., 77, 1057 (1958). Those compounds wherein X is C1-C3 alkoxy, amino, cyano, acetamido, or C1-C3 alkylthio, are prepared by methods disclosed in the above-cited references.

Suitable nonphytotoxic acid addition salts of the pyridine bases represented by the above formula can be prepared by methods well known to the art employing, for example, acids such as hydrochloric, hydrobromic, sulfuric, phosphoric and methanesulfonic.

The intermediate ketones are synthesized by methods well known in the art, which are exemplified in the following preparations.

Preparation 1 Isopropyl m-tolyl ketone In a three-neck round-bottom flask fitted with a mechanical stirrer, and a reflux condenser, and protected from moisture, there was placed 300 ml. of tetrahydrofuran, to which was added 10 g. of magnesium shavings. The mixture was then heated to refluxing. A catalytic amount of iodine was added, followed by the dropwise addition of 75 g. of m-bromotoluene. The Grignard reagent which was thus formed was a slate gray color. The reaction was held at reflux temperature until the magnesium had completely reacted. The reaction mixture was then cooled and 14 g. of isobutyronitrile was added dropwise to the mixture. The reaction product mixture was then heated to reflux for several hours. At the end of the heating period, the reaction product mixture was cooled and ammonium chloride hydrate was added, followed by concentrated hydrochloric acid, until the solution was acidic. The organic layer was separated, dried over anhydrous sodium sulfate, and concentrated in vacuo. There was obtained an oil which weighed about 38 g., and which was identified by NMR and IR spectra as isopropyl m-tolyl ketone.

Preparation 2 Isopropyl 3,4-methylenedioxyphenyl ketone The Grignard reagent prepared from 25 g. of isopropylbromide and 5 g. of magnesium turnings in 100 ml. of ether was allowed to react with 30 g. of 3,4methylenedioxybenzaldehyde, and the resulting isopropyl-3,4methylenedioxyphenylcarbinol was isolated and used without purification in the next step of the reaction.

The carbinol thus prepared was dispersed in about 200 ml. of glacial acetic acid with stirring, and to the mixture was added 20 g. of chromium trioxide dissolved in about 30 ml. of water. The addition was carried out carefully and the reaction temperature was kept below 80"C. Stirring of the mixture was centinued for about 4 hours. The reaction product mixture was cooled and poured onto a mixture of crushed ice and aqueous 50 percent sodium hydroxide solution, and the pH of the mixture was adjusted to pH 8. The mixture was extracted with large volumes of ether and the ether extracts combined and washed with dilute aqueous sodium hydroxide solution. The ether solution was dried and concentrated in vacuo to leave a residue. The residue was chromatographed over a silica column, using benzene as solvent and eluant, to yield 20 g. of product, which was identified by NMR and infrared spectrum as isopropyl 3,4-methylenedioxyphenyl ketone.

Preparation 3 5-(4-Chlorobenzoyl)-5-methyl- 1,3-dioxane Following the procedures taught by (a) Terada, Nippon Kagan Zasshi. 81. 612 (1960), Chem. Abst. 56, 1446 (1962); (b) British Patent No. 1,148,247, Chem. Abst. 71.

61394u (1969); (c) Wesslen, Acta. Chem. Scand. 23, 1033 (1969), a mixture of 50.7 g. of 4-chloropropiophenone, 90 g. of paraformaldehyde, 128 g. of BF3 etherate, and 300 ml. of acetonitrile was allowed to react, and there was isolated 10.5 g. of product having a melting point of about l08-1090C., after recrystallization from petroleum ether. The product was identified by NMR spectrum as 5 - (4 chlorobenzoyl) - 5 - methyl - 1,3 - dioxane.

Compounds of Formula I are synthesized following the general procedures taught in the references named above. Some typical syntheses are described in the following examples.

Example 1 a-Isopropyl-a-(3,4-xylyl)-3-pyridinemethanol In a multi-neck round-bottom flask equipped with a dropping funnel, a gasinlet tube, a mechanical stirrer, and protected from moisture, there was placed 500 ml. of anhydrous ether, and, while dry nitrogen was introduced into the flask through the gas-inlet tube, the whole was cooled at 700 C. To this cold ether, there was added in a single portion, 45 ml. of 2.1-2.3 molar hexane suspension of nbutyllithium. The mixture was stirred and cooled to 700 C. There was then added dropwise, with stirring, 13.5 g. of 3-bromopyridine, while the temperature of the mixture was held at -700C., plus or minus 3 . The mixture was stirred for 0.5 hour after addition of the 3-bromopyridine was completed, and then 15 g. of isopropyl 3,4-xylyl ketone was added dropwise with continued stirring. The reaction mixture was allowed to stir overnight and warm to ambient room temperature during that time. The reaction product mixture was worked up by adding water, separating the organic layer and extracting the aqueous layer several times with ether. The original ether layer and the ether extracts were combined and dried over anhydrous sodium sulfate. The drying agent was filtered off and most of the ether removed in vacuo.

The material which crystallized from the ether was filtered off and again recrystallized from ether to yield product weighing 11 g., and having a melting point of 109--1100C. The product was identified by NMR spectrum and elemental analyses as a - isopropyl - a - (3,4 - xylyl) - 3 - pyridinemethanol.

Analyses calculated for C,7H2,NO.

Theoretical Found C 79.96% 79.70% H 8.29 8.34 N 5.49 5.71 Example 2 a-(t-B utyl)-a-chloro-a-(4-fluorophenyl)-3-pyridinemethane hydrochloride A solution was prepared of 34 g. of a - (t - butyl) - a - (4 - fluorophenyl) 3 - pyridinemethanol in 300 ml. of benzene, and there was slowly added to the solution 16 g. of thionyl chloride. When addition was complete, the solution was refluxed for 2 hours. The reaction mixture was then cooled and filtered. The solid on the filter was washed with benzene. Additional material was obtained by concentrating the filtrate to dryness, leaving a residual solid which was also washed with benzene. The total amount of solid---product collected was 37 g. It had a melting point of 190--191"C., and was identified by NMR spectrum and elemental analyses as a - (t - butyl) - a - chloro - a - (4 - fluorophenyl)- 3 pyridinemethane hydrochloride.

Analyses calculated for C16H,7CIFN HCI: Theoretical Found C 69.19% 69.10% H 6.17 5.88 N 5.04 5.00 Example 3 a-(t-B utyl)-a-(4-fluorophenyl)-a-methoxy-3-pyridinemethane A solution of sodium methylate in methanol was prepared by adding 1 g. of metallic sodium to 150 ml. of absolute'methanol in a flask protected from atmospheric moisture. There was then added to the sodium methylate solution, 4 g. of a - (t - butyl) - - chloro - a - (4 - fluorophenyl) - 3 - pyridinemethane hydrochloride (prepared in Example 2). The reaction mixture was refluxed for 2 hours and then stirred overnight at ambient room temperature. The reaction product mixture was worked up by concentrating it at reduced pressure. To the residue thus obtained, there was added methylene dichloride and water. The methylene dichloride layer was separated and the aqueous layer was again extracted with methylene dichloride. The original methylene dichloride layer was combined with the extracts, and dried over anhydrous sodium sulfate. The drying agent was filtered off and the filtrate was concentrated in vacuo. The oil that was left as a residue was chromatographed over a silica gel column, elution being accomplished with a mixture containing 85 percent toluene and 15 percent acetone by volume. There was collected 2.5 g. of an oil identified by NMR spectrum and elemental analyses as a - (t - butyl) - ce - (4 - fluorophenyl) - a - methoxy - 3 - pyridinemethane.

Analyses calculated for C17H20FNO: Theoretical Found C 74.70% 74.50% H 7.39 7.30 N 5.12 4.92 Example 4 a,a-Diphenyl-a-morpholino-3-pyridylmethane To a solution of 15 g. of a,a-diphenyl-3-pyridinemethanol in 100 ml. of dichloromethane, there was added 25 ml. of thionyl chloride, and the mixture was refluxed for 3 hours. The reaction mixture was concentrated in vacuo. The residue was washed with benzene and again concentrated in vacuo. The residue which was obtained was a yellow semi-solid, which was dissolved in 200 ml. of morpholine and the solution refluxed for about 3 hours. The reaction product mixture was cooled and concentrated to dryness in vacuo, leaving a residue. Water was added to the residue and the gray solids which separated were filtered off and dissolved in methylene dichloride. the methylene dichloride solution was washed with water, dried over anhydrous magnesium sulfate, and the drying agent was filtered off. The filtrate was concentrated in vacuo to yield a gray solid weighing 16 g. This solid was recrystallized from hot acetone to yield product having a melting point of 280"C.

The product was identified by NMR spectrum and elemental analyses as a diphenyl-a-morpholino-3-pyridylmethane.

Analyses calculated for C22H22N2O: Theoretical Found C 79.97% 80.01% H 6.71 6.77 N 8.48 8.09 Example 5 a-(4-Chlorophenyl)-a-(4-chlorophenylthio)-3-pyridylmethane A mixture of 12 g. of a-chloro-3-(4-chlorobenzyl)pyridine, 8.5 g. of the sodium salt of 4-chlorothiophenol, and 100 ml. of dimethylformamide was refluxed for about 2 hours. The reacton product mixture was concentrated in vacuo and the residue taken up in 200 ml. of ether. The ether mixture was extracted with water.

The water layer was extracted once with 100 ml. of benzene. The ether layer and the benzene layer were combined and dried over anhydrous magnesium sulfate.

The drying agent was filtered off and the filtrate concentrated in vacuo and distilled at reduced pressure. The product obtained had a boiling point of about 180- 183"C./0.1 mm. and weighed 6 g. It had 712D 1.6509. The product was identified by NMR spectrum and elemental analyses as a - (4 - chlorophenyl)- a - (4 chlorophenylthio) - 3 - pyridylmethane. Yield: 6 g.

Analyses calculated for C18H13CI2NS: Theoretical Found C 62.43 62.24 H 3.78 3.84 N 4.04 3.89 The method of this invention is practiced by adding a compound of Formula I to the water in which aquatic weeds live. The compounds of Formula I inhibit the growth of aquatic weeds when a growth-inhibiting but not herbicidally-effective amount of one of the compounds is brought into contact with the weeds. Some weeds float in or on top of water; others are rooted in the underwater soil.

Depending on the type of weed of primary concern in a particular body of water, it may be advantageous to supply the compound in a form which sinks, floats, or is evenly dispersed throughout the water.

The method is preferably practiced by adding to the water an amount of the compound such that a concentration of from 0.25 ppm. by weight to 10 ppm. of the compound is obtained. Preferably, the concentration is in the range of from 0.25 to 2 ppm.

The optimum concentration for any specific weed-inhibiting problem varies with the temperature and the species of weeds to be controlled. At higher water temperatures, less compound is generally required for a given degree of control than is needed at low temperatures.

The compounds are preferably added to the water in the form of the growthinhibiting compositions of this invention. The inert ingredients of the compositions are similar to other agricultural chemical formulations.

In general, all pesticides, including the compounds of Formula I, are prepared in the form of comparatively concentrated compositions. Such compositions contain, in general, from 0.1% to 90% by weight of the compound of Formula I, and are in the forms of granules, wettable powders or emulsifiable concentrates.

Granules are applied by simply scattering them over the surface of the water.

They may be formulated to sink or float by adjusting the density. In general, granules contain from 0.1% to 10% by weight of the compound, dispersed in or adsorbed on particles of dried earth, stone or sand. Such earths as diatomaceous earths, kaolin, bentonite, montmorillonite and attapulgite are particularly useful for preparing granules of this invention, and comprise from 90% to 99.9 /O of the comnosition.

Compositions in the forms of wettable powders and emulsifiable concentrates are diluted in water to prepare a dilute composition, which is then sprayed over or otherwise applied to the weed-infested water. The concentration of the compound of Formula I in the dilute composition is not particularly important, since the efficacy of weed inhibition depends on the amount of compound applied to the water, and not upon the concentration of the dilute composition in which form it is applied.

Wettable powders comprise an intimate mixture of the active compound in an inert carrier which is a mixture of a fine inert powder and surfactants. The concentration of the active compound is usually from about 10 percent to about 90 percent by weight. The inert powder is usually chosen from among the attapulgite clays, the montmorillonite clays, the diatomaceous earths, or the purified silicates.

Effective surfactants, comprising from about 0.5 percent to about 10 percent of the wettable powder, are found among the sulfonated lignins, the condensed naphthalenesulfonates, the naphthalenesulfonates, the alkylbenzene sulfonates, the alkyl sulfates, the nonionic surfactants such as ethylene oxide adducts of alkyl phenol.

Typical emulsifiable concentrates of the compounds comprise a convenient concentration of the compound, such as from about to about 500 g. per liter of liquid, equivalent to from about 5 percent to about 50 percent, dissolved in an inert carrier which is a mixture of water-immiscible organic solvent and emulsifiers.

Useful organic solvents include the aromatics, especially the xylenes, and the petroleum fractions, especially the high-boiling naphthalenic and olefinic portions of petroleum such as heavy aromatic naphtha. Other organic solvents may also be used, such as the terpenic solvents including rosin derivatives, and complex alcohols such as 2-ethoxyethanol. Suitable emulsifiers for emulsifiable concentrates are chosen from the same types and concentrations of surfactants used for wettable powders.

A particularly preferred type of composition is the novel invert emulsion containing a compound of Formula I. Ordinary pesticidal emulsifiable concentrates form oil-in-water emulsions upon dilution. Such emulsions consist of a small amount of the organic phase dispersed in the form of microscopic droplets in the water phase.

Technology for forming water-in-oil emulsions, called invert emulsions, has rather recently been discovered. These emulsions consist of a large amount of water dispersed in the form of droplets in a small amount of the organic phase.

Such invert emulsions are in the physical form of a stiff mayonnaise-like cream which is applied to the water in which the weeds grow through atomizing nozzles which break the emulsion into small droplets. The invert emulsion has the advantageous properties of remaining in discrete droplet form for long periods of time while suspended in water, and of readily adhering to the foliage of aquatic plants.

Most invert emulsions tend to float, which is an advantage if floating weeds are to be treated. If the weeds of primary concern are submerged weeds, the invert emulsion can be made to sink by suspending a heavy, inert powder in it, or by dissolving an inert substance in either the organic or the water phase.

A compound of Formula I may be prepared as an invert emulsion composition in various manners. The compound may be dissolved in the organic phase, and may thereby be easily transported and marketed as an emulsifiable concentrate, which is combined with water at the time of application to prepare the invert emulsion.

The compound of Formula I may also be prepared in the form of a fine powder, suitably admixed with surface-active agents, which powder is then suspended in the organic phase. Again, the organic phase with the compound suspended therein would be the marketed and shipped form of the compound and would be diluted with water at the time of application.

A preferred way to prepare the invert emulsion composition makes use of a wettable powder composition of the compound of Formula I. The wettable powder is prepared in the usual way as described above, and is easily transported and marketed. When the invert emulsion composition is to be prepared, the wettable powder is dispersed in either the organic or the aqueous phase, and the phases are mixed as usual.

An excellent reference on the formulation and preparation of invert emulsions is Stull et al., U.S. 3,197,299 (July 27, 1965). It is there explained how invert emulsions are prepared, using approximately equal parts of organic and water phases. It should be pointed out, however, as will be shown in the examples below, that it is now possible to use much larger amounts of water, even up to 90% or 95% of the total invert emulsion composition.

As Stull et al., explained, it is often more convenient to prepare the invert emulsion composition substantially simultaneously with the application of it to the body of water. It is entirely possible to prepare the invert emulsion in a mixing tank, as an ordinary emulsion would be prepared, but the viscosity of the invert emulsion composition makes it difficult to pump and atomize. Invert emulsions are therefore most conveniently made by forcing the proper amounts of the two phases continuously into a mixing chamber, and thence out of the mixing chamber through the atomizing nozzle.

A number of types of surface-active agents will form invert emulsions. Stull taught the use of such emulsifying agents as alkyl aryl polyether alcohols, particularly pointing out the trademarked products Triton X-171 and Triton 9D208, produced by Rohm and Haas Company. Other typical surface-active agents which have been found effective for making invert emulsion compositions are oilsoluble alkanoylamides such as Emcol 511 and fatty acid polyglycerol esters such as Emcol 14. The Emcol surfactants are trademarked products of the Witco Chemical Company.

A widely-distributed product for the preparation of invert emulsion compositions is called Visko-Rhap Oil, which is a product of Rhodia Inc., Chipman Division.

Surfactants such as the above are usually mixed in the organic phase of the invert emulsion. The major part of the organic phase is a solvent. It has been found that citrus terpenes, a solvent prepared from the rind of citrus fruit, is a particularly useful solvent for the purpose. Stull, cited above, points to the use of petroleumbased solvents, particularly the non-phytotoxic horticultural base oils. It will be understood that the exact nature of the solvent is not particularly important, and that numerous types of solvents, including petroleum distillates, aliphatic hydrocarbons, aromatic hydrocarbons, and terpenic and naphthalenic solvents may be used as is economical or convenient for a given instance. Thus, the invert emulsion composition is prepared by mixing, either in a mixing tank or continuously, the organic phase and the water phase. The organic phase is composed of a solvent and one or more surface-active agents. The water phase most typically contains no special adjuvants.

The compound of Formula I may be dissolved in the organic phase, dispersed in either phase as a solid, or dispersed in the final emulsion after it is prepared.

Mqst typically and conveniently, the compound of Formula I will be formulated as a wettable powder as described above, and dispersed in either the organic or aqueous phase before the invert emulsion composition is prepared.

Various types of adjuvants may be used if desired. As discussed above, weighting agents may be added to adjust the density of the invert emulsion.

Additional surface-active agents may be added to enhance the ability of the emulsion to stick to or to spread across submerged vegetation. A particularly useful adjuvant is a complexed form of copper, particularly as an ethylene diamine tetraacetic acid complex. Such complexes, which may be readily obtained in solution form, serve as algicides and also increase the density of the invert emulsion composition.

As agricultural chemists will understand, the concentrations of the various ingredients in the invert emulsion composition vary over a rather wide range. In general, the compositions contain amounts of a compound of Formula I from 0.01% to 1% by weight, amounts of solvent from 3% to 30%, and amounts of surface-active agent from 0.5% to 5%. Adjuvants such as spreader-stickers and weighting agents need not be present, but may range up to 15% of the composition by weight. Accordingly, the amount of water in the composition may range from 49% to 96.49%.

The following exemplary invert emulsion composition formulae are presented as a further assistance and convenience to agricultural chemists who wish to practice this invention. In the examples below, the compounds of Formula I are identified by their numbers in the listing below.

Formula 1 Compound 12, as a 50% wettable powder 0.15% Orange terpenes 3.00 Copper complex solution, containing 9% Cu 11.80 Visko-Rhap Oil 1.70 Water 83.35 Formula 2 Compound 36 as a 75% wettable powder 0.55% Horticultural base oil 15.00 Powdered limestone 8.00 Emulsifier 2.50 Water 73.95 Formula 3 Compound 73, as a 25% wettable powder 3.1% Orange terpenes 10.0 Emcol 14 5.0 Molasses 10.0 Spreader-sticker 5.0 Water 66.9 Formula 4 Compound 83 as a 50% wettable powder 0.05% Diesel fuel 7.00 Emcol 511 1.80 Water 91.15 Formula 5 Compound 4 1.0% Horticultural base oil 20.0 Triton X-171 5.0 Spreader-sticker 5.0 Water 69.0 Formula 6 Compound 19, as a 50% wettable powder 1.4% Diesel fuel 5.0 Orange terpenes 6.0 Emulsifier 3.5 Water 84.1 Formula 7 Compound 84, as a 65% wettable powder 0.1% Horticultural base oil 3.0 Visko-Rhap Oil 0.5 Water 96.4 The novel aquatic growth regulating method and compositions for use therein are illustrated by the following experiments.

Experiment 1 The following method was used in the laboratory to evaluate the aquatic growth regulating properties of the compounds disclosed herein, when used at a concentration of 10 ppm., against a representative submerged aquatic weed.

The compounds for this test were formulated in the following manner. Twenty mg. of compound was weighed into a 12 ml. disposable vial. To the vial containing the compound were added 1 ml. of acetone and 9 ml. of aqueous 0.1 percent polyoxyethylene sorbitan monooleate (Tween 80). To obtain the test concentration of 10 ppm., 4.00 ml. of this stock solution was added to 785 ml. of water in a plastic container. The plastic containers used were flowerpot-shaped, having a bottom diameter of 9 cm., a top diameter of 11.5 cm., and a height of 13.5 cm.

Terminal pieces of Florida elodea, Hydrilla verticillata (L.F.), (hereinafter identified as hydrilla) 10 cm. long, without branching, were prepared for testing.

Three such cuttings were placed in each plastic container holding 785 ml. of water, to which water the formulated test compound had been added, along with 3 ml. of Hoagland's Nutrient solution. Three 10 cm. cuttings of hydrilla were placed in each of several control containers of water. To the water in each control container there was also added the amount of solvent used to formulate the test compound for each container.

After a period of two to three weeks, measurements were made to determine the total length of each plant. An average total growth was obtained by dividing the total combined lengths by the number of replicates. By subtracting 10 cm. from the average total length, the average increase in growth was obtained. This difference was divided by the average increase in length of the plants in the solvent controls (SC) and the quotient multiplied by 100 to give a percent inhibition.

Total combined length of Replicates =Average Length Number of Replicates Avg. Length-l0 cm.=Avg. Increased Growth Avg. Increased Growth (1- )x100=% Inhibit ion Avg. Increased Growth SC The compounds employed in this experiment, as well as in one or more of the experiments described hereinafter, are identified as follows: 1. 5-(p-Pyridyl)-5-hydroxynonane 2. 2-(p-Pyridyl)-2-heptanol 3. 2-(p-Pyridyl)-5-methyl-2-heptanol 4. 3-Pyridyl diphenylmethane 5. 3-[B is(4-fluorophenyl)methyl] pyridine 6. a,a-Diphenyl-3-pyridinemethanol 7. &alpha;-t-Butyl-&alpha;-(4-chlorophenyl)-3-pyridinemethanol 8. a-Cyclopropyl-a-(4-chlorophenyl)-3-pyridinemethanol 9. 5-Hydroxy-5-(3-pyridyl)- 10,11 -dihydro-5-dibenzola[a,d] cycloheptene 10. 9-Hydroxy-9-(3-pyridyl)fluorene 11. &alpha;-Ethyl-&alpha;-phenyl-3-pyridinemethanol 12. &alpha;-(4-Chlorophenyl)-&alpha;-cyclopropyl-3-pyridinemethanol.HCl 13. a-Chloro-a-(3-pyridyl)-4,4'-dichlorodiphenylmethane 14. 9-(3-Pyridyl)fluorene 15. a-(3-Pyridyl)benzyl alcohol 16. a-Cyclobutyl-a-(4-methoxyphenyl)-3;pyridinemethanol 17. a-Cyclohexyl-a-(4-phenoxy-n-butyl)-3-pyridinemethanol 18. a-Cyclohexyl-a-(2-cyclohexylethyl)-3-pyridinemethanol 19, &alpha;-Isopropyl-&alpha;-(4-methoxyphenyl)-3-pyridinemethanol 20. a,a-B is(3-pyridyl)benzyl alcohol 21. a-(2-Chlorophenyl)-3-pyridinemethanol 22. a-(2-Chlorophenyl)- < r-methyl- 3-pyridinemethanol 23. &alpha;-(4-Chlorophenyl)-&alpha;-ethynyl-3-pyridinemethanol 24. a,a-B is(n-pentyl)-3-pyridinemethanol HCI 25. &alpha;-(n-Hexyl)-&alpha;-methyl-3-pyridinemethanol 26. &alpha;-Isopropyl-&alpha;-(4-propoxyphenyl)-3-pyridinemethanol 27. a-(2-Chlorophenyl)-a-(n-hexyl)-3-pyridinemethanol 28. a-(4-Chlorophenyl)-3-pyridinemethanol 29. a,a-Dibenzyl-3-pyridinemethanol 30. 9-(3-Pyridyl)thioxanthen-9-ol 31. &alpha;-(t-Butyl)-&alpha;-(4-propoxyphenyl)-3-pyridinemethanol 32. &alpha;-(p-Cumenyl)-&alpha;-isopropyl-3-pyridinemethanol 33. cE-(t-Butyl)-a-(4-methoxyphenyl)-3-pyridinemethanol 34. a-Cyclohexylmethyl-3-pyridinemethanol 35. a-Cyclohexyl-a,a-bis(3-pyridyl)methanol 36. a,a-B is(3-pyridyl)-n-nonanol 37. a,a-B is(isobutyl)-3-pyridinemethanol 38. 3-[1-(2-Chlorophenyl)-n-heptyl]pyridine 39. a-(4-chlorophenyl)-a-(4-chlorophenylthio)-3-pyridylmethane 40. 3-(4,4'-Dichloro-a-ethoxydiphenylmethyl)pyridine 41. cE-cyclobutyl-a-(4-fluorophenyl)-3-pyridinemethanol 42. a-Pentafluorophenyl-ce-phenyl-3-pyridinemethanol 43. 3-(a-Ethylbenzyl)pyridine 44. a-Phenyl-a-(2-thienyl)-3-pyridine methandl 45. 9-(3-Pyridyl)-9-fluorenol HCI 46. &alpha;-Propyl-&alpha;-(2-thienyl)-3-pyridinemethanol 47. &alpha;-Methyl-&alpha;-(4-phenoxyphenyl)-3-pyridinemethanol 48. &alpha;-(4-Chlorophenyl)-&alpha;-methyl-3-pyridinemethanol 49. &alpha;-(4-Bromophenyl)-2-ethyl-3-pyridinemethanol 50. &alpha;-Isopropyl-&alpha;-phenyl-3-pyridinemethanol 51. &alpha;,&alpha;-Bis(cyclpropyl)-3-pyridinemethanol.HCl 52. 5-(3-Pyridyl)-10,11-ihydro-5H-dibenzo]a,d]cycloheptene 53. 9-(3-Pyridyl)xanthen-9-ol 54. 9-(3-Pyridyl)thioxanthen-9-ol 55. &alpha;,&alpha;-Bis(cyclohexyl)-3-pyridinemethanol 56. 5-(3-Pyridyl)-5H-dibenzo[a,d]cyclohepten-5-ol-HCl 57. &alpha;-(4-Chlorophenyl)-&alpha;-cyclohexyl-3-pyridinemethanol.HCl 58. 3-(4-Chloro-&alpha;-isopropylbenzyl)pyridine 59. a,a-Diisopropyl-3-pyridinemethanol 60. &alpha;,&alpha;-Diisopentyl-3-pyridinemethanol.HCl 61. &alpha;-(n-Hexyl)-&alpha;-isobutyl-3-pyridinemethanol.HCl 61. &alpha;,&alpha;-Diphenyl-3-pyridineacetonitrile 63. &alpha;-(3-Ethyl-n-pnetyl)-&alpha;-isobutyl-3-pyridinemethanol.HCl 64. &alpha;-methyl-&alpha;-(n-nonyl)-3-pyridinemethanol 65. &alpha;,&alpha;-Bis(n-pentyl)-3-pyridinemethanol 66. &alpha;-(n-Heptyl)-&alpha;-isobutyl-3-pyridinemethanol 67. &alpha;-Cyclopropyl-&alpha;-(4-fluorophenyl)-3-pyridinemethanol 68. &alpha;,&alpha;-Bis(cyclohexylmethyl)-3-pyridinemethanol 69. &alpha;-Cyclohexyl-&alpha;-isopropyl-&alpha;-pyridinemethanol 70. &alpha;-(2,4-difluorophenyl)-&alpha;-phenyl-3-pyridinemethanol 71. &alpha;-(4-Methoxyphenyl)-&alpha;-neopentyl-3-pyridinemethanol 72. &alpha;-Isopropyl-&alpha;-(&alpha;,&alpha;,&alpha;-trifluoro-m-toyl)-3-pyridinemethanol 73. 3-(&alpha;,p-Dimethoxybenzyl)pyridine 74. &alpha;-(n-Hexyl)-&alpha;-isobutyl-3-pyridinemethanol 75. &alpha;-(n-heptyl)-&alpha;-isobutyl-3-pyridinemethanol.HCl 76. 3-Butylpyridine 77. a-(n-Hexyl)-a-isopropyl-3-pyridinemethanol 78. &alpha;-(m-chlorophenyl)-3-pyridinemethanol 79. 3-(&alpha;-t-Butyl)-&alpha;-(4-Chlorophenyl)-&alpha;-(imidazol-1-yl)-3-pyridylmethane 80. &alpha;-Isoproyl-&alpha;-(3,4-xylyl)-3-pyridinemethanol 81. &alpha;-Isopropyl-&alpha;-(p-tolyl)-3-pyridinemethanol 82. &alpha;-Isopropyl-&alpha;-(m-tolyl)-3-pyridinemethanol 83. N-[Bis(4-chlorophenyl)-3-pyridinemethyl]acetamide 84. &alpha;-(Cyclohexylmethyl)-&alpha;-(n-octyl)-3-pyridinemethanol 85. &alpha;-(4-Chlorophenyl)-&alpha;-isopropyl-3-pyridinemethanol 86. &alpha;-(t-Butyl)-&alpha;-(4-fluorophenyl)-3-pyridinemethanol 87. &alpha;-(t-Butyl)-&alpha;-chloro-&alpha;-84-luorophenyl)-3-pyridinemethane 88. &alpha;-(t-Butyl)-&alpha;-(4-fluorohenyl)-&alpha;-methoxy-3-pyridylmethane 89. &alpha;-sec.-Butyl-&alpha;-pentyl-3-pyridinemethanol 90. &alpha;-Heptyl-&alpha;-isopropyl-3-pyridinemethanol 91. &alpha;-(t-BUtyl)-&alpha;-(4-fluorophenyl)-&alpha;-propoxy-3-pyridylmethane 92, 3-(9-Methoxyfluoren-9-yl)pyridine 93. 3-(9-chlorofluoren-9-yl)pyridine 94. a-(4-chlorophenyl)-a-(5-methyl- 1,3-dioxan-5-yl)-3-pyridine- methanol.HCl 95. &alpha;-(5-Methyl-1,3-dioxan-5-yl)-&alpha;-phenyl-3-pyridinemethanol.HCl 96. &alpha;-(2,4-dichlorophenyl)-&alpha;-(1,3-dioxan-5-yl)-3-pyridinemethanol 97. &alpha;,&alpha;-Bis(4-chlorophenyl)-3-pyridinemethanol 98. &alpha;,&alpha;-Diphenyl--morpholino-3-pyridylmethane 99. &alpha;-Isopropyl-&alpha;-[3,4-(methylenedioxy)phenyl]-3-pyridinemethanol 100. &alpha;-(4-Chlorophebnyl)-&alpha;-8n-pentylthio)-3-pyridinemethanol 101. &alpha;-(4-Chlorophenyl)-N,N-di(n-propyl)-3-pyridylmethylamine 102. &alpha;-(4-Chlorophenyl)-&alpha;-cyclohexylthio-3-pyridylmethane.

The results of the tests, run at the concentration of 10 ppm. of compound, and observed at the end of three weeks, are set forth in the table which follows. In the table, the number in column I identifies the test compound; column 2 lists the percent growth inhibition of hydrilla observed.

TABLE I Substituted 3-Pyridine Derivatives Approx. % Growth Compound Inhibition 95 2 95 3 93 4 100 5 100 6 95 7 98 8 99 9 82 10 83 11 100 12 98 13 53 14 84 15 99 16 96 17 95 18 94 19 81 20 78 21 83 22 85 23 88 24 100 25 92 26 98 27 100 28 94 29 97 30 75 31 90 32 96 33 93 34 92 35 65 36 97 37 99 38 97 39 93 40 90 41 96 42 84 43 95 44 87 45 91 46 90 47 62 48 92 49 96 50 96 51 59 52 91 53 92 54 66 55 100 56 62 57 100 58 99 59 77 60 100 TABLE 1 Continued Substituted 3-Pyridine Derivatives Approx. % Growth Compound Inhibition 61 100 62 96 63 99 64 94 65 100 66 100 67 100 68 97 69 96 70 72 71 93 72 97 73 75 74 100 75 100 76 97 77 100 78 89 79 98 80 96 81 97 82 97 83 78 84 93 85 99 86 86 87 92 88 100 89 95 90 95 91 98 92 96 93 92 94 92 95 90 96 97.

97 71 98 92 99 92 100 91 101 100 102 98 Experiment 2 The general procedure of Experiment 1 was repeated using a number of the same compounds at test concentrations of 1, 0.5 and 0.25 ppm.

The test compounds were formulated in the following manner: Twenty mg. of compound was weighed into a 12 ml. disposable vial. To the vial containing the compound were added I ml. of acetone and 9 ml. aqueous 0.1 percent polyoxyethylene sorbitan monooleate. This solution was designated as stock solution A.

The 1 ppm. test concentration was obtained as follows: Four ml. of stock solution A was diluted with 36 ml. of aqueous 0.1 percent polyoxyethylene sorbitan monooleate to give stock solution B. Four ml. of stock solution B, when added to 785 ml. water in the plastic test containers, gave a concentration of test compound of I ppm. The plastic test containers were identical to those employed in Experiment 1.

The 0.5 ppm. concentration of test compound was obtained as follows: Stock solution B, 20 ml., was diluted with 20 ml. aqueous 0.1 percent polyoxyethylene sorbiton monoleate, and this solution was designated stock solution C. Four ml. of stock solution C was added to 785 ml. of water in the plastic test containers to give a concentration of 0.5 ppm.

The 0.25 - ppm concentration of test compound was obtained as follows: Stock solution C, 20 ml., was diluted with 20 ml. aqueous 0.1 percent polyoxyethylene sorbitan monooleate to give stock solution D. This stock solution D, 4 ml., added to 785 ml. of water in the plastic test containers gave a concentration of test compound of 0.25 ppm.

Three weeks after the date of application of the test compounds, measurements were made on the total growth of each plant, as described in Experiment 1, and the percent inhibition observed was calculated using the formulas set forth in Experiment 1, above. The results are recorded in the table which follows. The test compounds are each identified by the same number as used in Experiment 1.

TABLE 2 Substituted 3-Pyridine Derivatives Approx. % Growth Inhibition at Indicated Test Concentrations Compound 1 ppm. 0.5 ppm. 0.25 ppm.

1 46 26 37 3 48 35 15 4 73 63 58 6 93 89 87 8 87 87 65 11 37 31 17 12 97 92 90 17 92 92 91 18 79 70 66 19 95 44 43 37 93 88 85 39 70 66 59 45 86 83 87 52 66 65 80 53 85 80 70 59 72 22 18 61 -6 82 48 66 90 83 89 69 90 90 88 71 70 71 55 72 51 35 58 75 98 92 81 76 90 84 73 77 88 72 55 78 87 84 63 85 91 87 69 86 100 93 91 88 80 87 85 89 97 95 88 91 88 82 72 93 53 41 38 98 80 71 68 99 57 34 36 100 73 65 52 101 76 54 51 102 80 73 73 Experiment 3 A field test to establish the efficacy of selected compounds of the above formula as growth regulators of submerged and floating aquatic weeds was conducted in the following manner.

Individual tanks three feet in diameter and about two feet deep were each filled with 80 gallons of water. A layer of 6 inches of a mixture of sand-clay loam soil (50:50) was placed in the bottom of each tank. Three of the plants to be used in the test, namely Florida elodea, Southern naiad, and Eurasian milfoil, were prepared by cutting 4-inch terminal stems and burying the lower one inch of each stem in the soil in the tank. The surface of the soil was divided into four quadrants and each plant was planted in a separate quadrant. The plants were allowed a period of about two weeks to become rooted. About 10 days after these aquatic plants had been planted, 10 Gambusia affinis (mosquito fish) were added to each pool. About 4 days later, two sprigs of coontail were added to each pool, as well as sufficient duckweed to cover 1/4 to 1/2 the water surface of each pool.

The compounds were tested at application rates of 2, 1 and 0.5 ppm. The test compounds were formulated by weighing 666.67 mg. (for 3 ppm.), 333.34 mg. (for I ppm.), and 166.67 mg (for 0.5 ppm.), and adding each weight to a mixture of 6 ml. of acetone and 54 ml. of aqueous 0.1 percent solution of Tween (Registered Trade Mark) 80 (polyoxyethylene sorbitan monooleate). This provided approximately 60 ml. total volume of each formulation. There were two replicates per rate as well as six replicates, that is six pools, which received 60 ml. of the solvent, and 12 pools which served as untreated controls. Each pool was treated by pouring the 60 ml. of the formulated material directly into the pool and stirring the water to distribute the test compound.

The aquatic plants used in the test are identified by letters of the alphabet as follows: A. Duckweed, Lemna minor L.

B. Coontail, Ceratophyllum demersum (L.) C. Eurasian milfoil, Myriophyllum specatum L.

D. Florida elodea, hydrilla veticillata (L.F.) E. Southern naiad, Najas guadalupensis (Spreng.) Observations of the growth regulation achieved by the test compounds were made at 3 weeks, 7 weeks, 10 weeks, and 12 weeks. The activity of the test compounds was compared in each case with the solvent controls. No fish toxicity was observed at any time throughout the period of the test. The growth inhibition was evaluated on a scale of 0 to 100 percent. As more than one determination was carried out at each rate, an average value was calculated.

The compounds employed in this field trial are identified by numbers, as set forth in Experiment 1.

The results of this field trial are recorded in Table 3, which follows. In the table, the number in column 1 identifies the test compound; column 2 indicates the application rate in parts per million (ppm.); column 3 indicates the weeks after treatment when the observation was made; and column 4 through 8 list the approximate percent inhibition of the particular aquatic weed observed.

TABLE 3 Appln. Weeks Rate After Cmp. ppm. Treatment A B C D E 6 2 3 100 100 60 100 100 1 100 100 60 100 100 0.5 100 100 60 90 100 2 7 100 100 40 100 100 1 100 100 20 100 100 0.5 100 100 15 90 100 2 10 100 100 40 100 100 1 100 100 0 100 100 0.5 100 100 0 90 100 2 12 100 100 0 100 100 1 100 100 0 99 100 0.5 100 100 0 93 100 12 2 3 100 100 100 100 100 100 100 90 100 90 0.5 100 100 80 100 90 2 7 100 100 100 100 100 1 100 100 80 100 100 0.5 100 100 60 100 100 2 10 100 100 100 100 100 100 100 30 100 100 0.5 100 100 10 100 100 TABLE 3 Continued Appln. Weeks Rate After Cmp. ppm. Treatment A B C D E 2 12 100 100 98 100 100 100 100 20 100 100 0.5 100 100 0 100 100 37 2 3 100 100 100 100 100 1 100 100 100 100 100 0.5 100 100 95 90 100 2 7 100 98 100 100 100 1 100 83 100 70 100 0.5 100 95 85 15 100 2 10 100 100 100 100 100 1 100 100 100 70 100 0.5 100 100 100 5 100 2 12 100 100 100 99 100 1 100 100 99 55 100 0.5 100 100 98 0 100 74 2 3 100 65 100 95 95 100 50 100 90 70 0.5 100 45 80 75 45 2 7 100 78 85 95 100 100 60 75 65 98 0.5 100 60 10 35 80 2 10 100 100 10 10 75 1 100 100 0 5 60 0.5 100 100 0 0 45 2 12 100 100 0 0 50 1 100 100 0 0 50 0.5 100 100 0 0 35 76 2 3 0 10 10 10 10 1 0 0 0 0 0 0.5 0 0 0 0 0 85 2 3 100 100 100 100 100 1 100 100 100 100 100 0.5 100 100 100 100 100 2 7 100 100 100 100 100 1 100 100 100 100 100 0.5 100 100 95 100 100 2 10 100 100 100 100 100 1 100 100 98 100 100 0.5 100 100 80 95 100 2 12 100 100 100 100 100 100 100 97 100 100 0.5 100 100 50 95 100 SC* 0 3 0 0 0 0 0 0 7 60 0 0 0 0 0 10 99 100 0 0 0 0 12 100 100 0 0 0 *SC-Solvent Control Experiment 4 A study was conducted of the time exposure effect of ce-(4-chlorophenyl)-cg- isopropyl-3-pyridinemethanol on Florida elodea (Hydrilla veticillata), hereinafter referred to as hydrilla. The procedure and materials used in this study are described as follows.

Twelve battery jars were set up, with each jar containing 1000 ml. of dechlorinated tap water. To the water in each jar there was added 4 ml. of Hoagland's Nutrient solution and 24 cuttings of hydrilla, each cutting being 10 cm. in length. The test compound was formulated by weighing out weights of 20 mg., 10 mg., and 2 mg., and each of these weights of compound was then dissolved in 1 ml. of acetone plus 9 ml. of aqueous 0. I percent polyoxyethylene sorbitan monooleate, yielding three solutions having a volume of 10 ml. each. Each solution was divided equally between two battery jars to give two battery jars containing 10 ppm. of test compound, two battery jars containing 5 ppm. of test compound, and two battery jars containing I ppm. of test compound. The remaining six battery jars were divided into three groups, each containing two jars, and an amount of solvent equivalent to that used to give the formulations of 10, 5 and I ppm., respectively, was added to the jars of each group, to serve as solvent controls.

Three plants were removed from each jar into a 750 ml. plastic carton containing 750 ml. of dechlorinated tap water plus 3 ml. of Hoagland's nutrient solution and 4 ml. of aqueous 0.1 percent Tween 80 (polyoxyethylene sorbitan monooleate) solution at time intervals equal to approximately 10 minutes, 3 hours, 6 hours, 12 hours, 24 hours, 48 hours, and 72 hours. Left remaining in the battery jars were three plant cuttings for a continuous exposure of 3 weeks to the test compound or to the solvent controls. Weekly measurements were made of the plants to determine the total length of each plant. The calculations of the percent inhibition observed were carried out using the formula disclosed in Experiment 1, above. The results of the tests, as calculated at the end of 1 week, 2 weeks and 3 weeks, are set forth in the table which follows. In the table, column 1 identifies the time of exposure of the plant to the test compound; column 2, the percent growth inhibition of hydrilla observed in the solvent controls; column 3, the percent growth inhibition of hydrilla observed at the application rate of 1 ppm.; column 4, the percent growth inhibition observed at application rate of 5 ppm.; and column 5, the percent growth inhibition of hydrilla observed at an application rate of 10 ppm.

The table is divided into three parts in order to record the percent inhibition observed at the end of I week, 2 weeks and 3 weeks.

TABLE 4 % Inhibition Observed Weekly at Indicated Application Rate 1 week Exposure Time SC I ppm. 5 ppm. 10 ppm. lOmin. 0 46 40 46 3 hr. 0 49 42 54 6 her. 0 43 51 49 12 her. 0 57 60 67 24 her. 0 66 75 73 48hr. 0 63 80 80 72 hr. 0 74 82 81 continuous 0 75 89 89 2 weeks 10 min. 0 37 38 48 3hr. 0 43 53 64 6 her. 0 41 70 67 12 hr. 0 47 71 77 24 hr. 0 56 80 81 48 hr. 0 55 81 85 72 hr. 0 66 85 87 continuous 0 89 96 98 3 weeks 10 min. 0 22 23 34 3 hr. 0 37 52 60 6 hr 0 36 74 70 12 hr. 0 45 73 83 24 hr. 0 48 79 84 48 hr. 0 55 85 90 72 hr. 0 60 88 92 continuous 0 92 97 100 The results of this experiment indicate that the test compound, a-(4 chlorophenyl)-cw-isopropyl-3-pyridinemethanol, is rapidly taken up by Hydrilla verticillata, and 10 minutes of exposure to the compound is sufficient to achieve considerable inhibition of growth for about a week. Longer exposure, of course, promotes inhibition of growth for longer periods of time.

Claims (42)

WHAT WE CLAIM IS:

1. A composition for inhibiting the growth of aquatic weeds in the form of a water-in-oil emulsion which comprises an inert carrier and a compound of the formula

wherein X is hydrogen, hydroxyl, halo, C1-C3 alkoxy, C1-C6 alkylthio, cyclohexylthio, 4-chlorophenylthio, -N(R3)2, acetamido, amidazol- I -yl, morpholino, or cyano; R' is hydrogen, C1-C9 alkyl, ethynyl, C3-C6 cycloalkyl, benzyl, phenyl, or monohalophenyl; R2 is C1-C9 alkyl, C3-C6 cycloalkyl, cyclohexylmethyl, cyclohexylethyl, phenyl, monohalophenyl, dihalophenyl, 3,4-(methylenedioxy)phenyl, trifluoromethylphenyl, p-cumenyl, tolyl, phenoxyphenyl, phenoxy(C1-C4)alkyl, benzyl, C1-C4 alkoxyphenyl, pentafluorophenyl, xylyl, 2-thienyl, 3-pyridyl, 1,3 dioxan-5-yl, or 5-methyl-1,3-dioxan-5-yl; R' and R2, when taken together with the carbon atom to which they are attached, form 2,6 - dimethylcyclohexan - 1 - yl, 9 - fluorenyl, 10,11 - dihydro 5 H - d i b e n z o [a,d] c y c l o h e p t e n - 5 - y l, 9 - x a n t h e n y l, 5 H dibenzo[a,d]cycylohepten - 5 - yl, or 9 - thioxanthenyl: R is hydrogen or C1-C6 alkyl; and the nonphytotoxic acid addition salts thereof.

2. A composition of claim 1 wherein the compound of Formula I is a compound wherein X is hydrogen, hydroxyl or methoxy; R' is hydrogen, C1-C8 alkyl, C3-C6 cycloalkyl, or phenyl; R2 is C1-C8 alkyl, cyclohexylmethyl, cyclohexyl, phenyl, 4-fluorophenyl, 4 chlorophenyl, 4-methoxyphenyl, p-tolyl, or 4-phenoxy-n-butyl; R' and R2, when taken together with the carbon atom to which they are a t t a c h e d, f o r m 9 - f l u o r e n y l, 9 - x a n t h e n y l, or 10, 11 - d i h y d r o - 5 H dibenzo[a,d]ccylohepten-5-yl; and the nonphytotoxic acid addition salts thereof.

3. A composition of Claim 2 wherein the compound of Formula I is a compound wherein X is hydrogen, hydroxyl or methoxy; R1 is C3-C8 alkyl, cyclopropyl, cyclohexyl, or phenyl; R2 is C4-C7 alkyl, 4-chlorophenyl, 4-fluorophenyl, 4-methoxyphenyl, p-tolyl, cyclohexylmethyl, phenyl, or 4-phenoxy-n-butyl; R' and R2, when taken together with the carbon to which they are attached, form 9-fluorenyl; and the nonphytotoxic acid addition salts thereof.

4. A composition of Claim 3 wherein the compound of Formula I is a compound wherein X is hydroxyl; R' is isopropyl, cyclopropyl, t-butyl, isobutyl or phenyl; R2 is n-hexyl, phenyl, 4-fluorophenyl, 4-methoxyphenyl, or 4-chlorophenyl; and the nonphytotoxic acid addition salts thereof.

5. The composition of Claim 3 wherein the compound is &alpha;,&alpha;-diphenyl-3- pyridinemethanol.

6. The composition of Claim 3 wherein the compound is &alpha;-(4-chlorophenyl)-&alpha;- cyclopropyl-3-pyridinemethanmol hydrochloride.

7. The composition or Claim 3 wherein the compound is &alpha;,&alpha;-diisobutyl-3- pyridinemethanol.

8. The composition of Claim 3 wherein the compound is a-hexyl-cg-isobutyl-3- pyridinemethanol.

9. The composition of Claim 3 wherein the compound is a-(4-chlorophenyl)-cr- isopropyl-3-pyridinemethanol.

10. The composition of Claim 3 wherein the compound is 3-pyridyl diphenylmethane.

I 1. The composition of Claim 3 wherein the compound is a-isopropyl-a-(4methoxyphenyl)-3-pyridinemethanol.

12. The composition of claim 3 wherein the compound is a-(t-butyl)-a-(4- fluorophenyl)-3-pyridinemethanol.

113. A composition of any of Claims 1-12 wherein the concentration of the compound is from 0.01 to 1% by weight.

14. A composition of any of Claims 1-12 comprising citrus terpenes as a solvent.

15. A composition of any of Claims 1-2 which is more dense than water.

16. A composition of any o claims 1-12 wherein the compound is in the form of a finely-divided solid dispersed in the composition.

17. A composition of any of Claims 1-12 additionally comprising an aromatic solvent.

18. A composition of any of Claims 1-12 additionally comprising a petroleum distillate as a solvent.

19. A composition of any of claims 1-.12 wherein the concentraton of water is from 80% to 90% by weight.

20. A method for inhibiting the growth of aquatic weeds which comprises adding to the water containing said weeds an amount sufficient to provide a growth-inhibiting and non-herbicidal concentration of a compound of the formula

wherein X is hydrogen, hydroxyl, halo, C1-C3 alkoxy, C1-C6 alkylthio, cyclohexylthio, 4-chlorophenylthio, -N(R )2, acetamido, imidazol-1-yl, morpholino, or cyano; R' is hydrogen, C1-C9 alkyl, ethynyl, C3-C6 cycloalkyl benzyl, phenyl, or monohalophenyl R2 is C1-C9 alkyl, C3-C6 cycloalkyl, cyclohexylmethyl, cyclohexylethyl, phenyl, monohalophenyl, dihalophenyl, 3,4-(methylenedioxy)phenyl, trifluoromethyphenyl, p-cumenyl, tolyl, phenoxyphenyl, phenopxy(C1-C4)alkyl, benzyl, C1-C4 alkoxyphenyl, pentafluorophenyl, xylyl, 2-thienyl, 3-pyridyl, 1,3dioxan-5-yl, or 5-methyl-I ,3-dioxan-5-yl; R' and R2, when taken together with the carbon atom to which they are attached, form 2,6-dimethylcyclohexan- 1 -yl, 9-fluorenyl, 10,11 -dihydro-5H- dibenzo[l,b]cyclohepten-5-yl, 9-xanthenyl, 5H-dibenzo[a,d,]cyclohepten-5-yl, or 9-thioxanthenyl; R3 is hydrogen or C1C6 alkyl; and the nonphytotoxic acid addition salts thereof.

21. A method of Claim 20 wherein the compound of Formula I is a compound wherein X is hydrogen, hydroxyl or methoxy; R is hydrogen, C1-C8 alkyl, C3-C6 cycloalkyl, or phenyl; R is C1-C8 alkyl, cyclohexylmethyl, cyclohexyl, phenyl, 4-fluorophenyl, 4 chlorophenyl, 4-methoxyphenyl, p-tolyl, or 4-phenoxy-n-butyl; R' and R2, when taken together with the carbon atom to which they are attached, form 9-fluorenyl, 9-xanthenyl, or 10,11-dihydro-5Hdibenzo[a,d]cyclohepten-5-yl; and the nonphytotoxic acid addition salts thereof.

22. A method of Claim 21 wherein the compound of Formula I is a compound wherein X is hydrogen, hydroxyl or methoxy; R' is C3-C8 alkyl, cyclopropyl, cyclohexyl, or phenyl; R2 is C4-C7 alkyl, 4-chlorophenyl, 4-fluorophenyl, 4-methoxyphenyl, p-tolyl, cyclohexylmethyl, phenyl, or 4-phenoxy-n-butyl; R' and R2, when taken together with the carbon to which they are attached, form 9-fluorenyl; and the nonphytotoxic acid addition salts thereof.

23. A method of claim 22 wherein the compound of Formula I is a compound wherein X is hydroxyl; R' is isopropyl, cyclopropyl, t-butyl, isobutyl or phenyl; R2 is n-hexyl, phenyl, 4-fluorophenyl, 4-methoxyphenyl, or 4-chlorophenyl; and the nonphytotoxic acid addition salts thereof.

24. The method of Claim 22 wherein the compound is a,a-diphenyl-3pyridinemethanol.

25. The method of Claim 22 wherein the compound is a-(4-chlorophenyl)-a- cyclopropyl-3-pyridinemethanol hydrochloride.

26. The method of Claim 22 wherein the compound is a,a-diisobutyl-3- pyridinemethanol.

27. The method of Claim 22 wherein the compound is c-hexyl-cr-isobutyl-3- pyridinemethnaol.

28. The method of Claim 22 wherein the compound is a-(4-chlorophenyl)-a- isopropyl-3-pyridinemethanol.

29. The method of Claim 22 wherein the compound is 3-pyridyl diphenylmethane.

30. The method of Claim 22 wherein the compound is a-isopropyl-cg-(4- methoxyphenyl)-3-pyridinemethanol.

31. The method of Claim 22 wherein the compound is a-(t-butyl)-a-(4- fluorophenyl)-3-pyridinemethanol.

32. A method of any of Claims 2031 wherein the concentration of the compound in the water is from 0.25 ppm. to 10 ppm. by weight.

33. A method of Claim 32 wherein the concentration of the compound in the water is from 0.25 ppm. to 2 ppm. by weight.

34. A method of any of Claims 2031 wherein the compound is added to the water in the form of a water-in-oil emulsion in which the concentration of the compound is from 0.01% to 1% by weight.

35. A method of any of Claims 2031 wherein the compound is added to the water in the form of a water-in-oil emulsion wherein citrus terpenes are present as a solvent.

36. A method of any of Claims 231 wherein the compound is added to the water in the form of a water-in-oil emulsion which is more dense than water.

37. A method of any of Claims 2-31 wherein the compound is added to the water in the form of a water-in-oil emulsion wherein the compound is in the form of a finely-divided solid dispersed in the composition.

38. A method of any of Claims 2031 wherein the compound is added to the water in the form of a water-in-oil emulsion wherein an aromatic solvent is used.

39. A method of any of Claims 2031 wherein the compound is added to the water in the form of a water-in-oil emulsion wherein a petroleum distillate is used as solvent.

40. A method of any of Claims 2031 wherein the compound is added to the water in the form of a water-in-oil emulsion wherein the concentration of water is from 80% to 90% by weight.

41. A composition as claimed in Claim I substantially as described hereinbefore with particular reference to any one of the Examples.

42. A method as claimed in Claim 20 substantially as described hereinbefore with particular reference to any one of the Examples.