[0001] The invention relates (a).to novel pyridyloxy(thio)-phenoxy propanoic acids, salts
and esters thereof and pyridyl(oxy/thio)phenoxy propanols and esters and ethers thereof,
and propionitriles, (b) to herbicidal compositions of such compounds and (c) to methods
of using such compounds for the control of undesired plant growth. The compounds are
particularly useful for control of grassy weeds.
[0002] The present invention provides a trifluoromethylpyridyl(oxythio)phenoxypropionic
compound corresponding to the formula
wherein T is oxygen or sulfur;
X is Cl, Br, or CF3;
Y is H, Cl, Br, or CF3, provided at least one of X and Y is CF3;
Z is
-CN, -CH20R3,
M is ⊕NHR1R1R1, Na, K, Mg, or Ca;
R is H, C1-8 alkyl, benzyl, chlorobenzyl, or C3-6 alkoxyalkyl;
R1 is H, C1-4 alkyl, or C2-3 hydroxyalkyl;
R2 is R1 or -OCH3 ;
R3 is H or C1-4 alkyl;
R4 is C1-7 alkyl; and
R5 is C1-4 alkyl.
[0003] The compounds of the above formula, hereinafter referred to for convenience as "active
ingredients", have been found to be especially active as herbicides for the control
of undesired vegetation, for example, grassy or graminaceous weeds. Accordingly, the
present invention also encompasses compositions containing one or more active ingredients
as well as preemergent and postemergent methods of controlling undesired plant growth,
especially in the presence of valuable crops. Such methods comprise applying a herbicidally-effective
amount of one or more active ingredients to the locus of the undesired plants, that
is, the seeds, foliage, rhizomes, stems and roots or other parts of the growing plants
or soil in which the plants are growing or may be found.
[0004] The compounds of the present invention are generally oils or crystalline solids at
ambient temperatures which are soluble in many organic solvents commonly employed
as herbicidal carriers. The active ingredients of the above formula wherein T is oxygen,
X is CF
3, Y is Cl or H, and Z is
wherein R is Cl-C8 alkyl constitute preferred embodiments of the present invention. The active ingredients
of the above formula wherein T is oxygen, X is CF3, Y is Cl, Br, CF3 or hydrogen, Z is
constitute additional preferred bodiments. Yet additional preferred embodiments are
the present compounds wherein T is sulfur, X is CF3, Y is Cl, and Z is
wherein R is H or C1-C8 alkyl.
[0005] The compounds of the present invention wherein T is oxygen can be readily prepared
by the reaction of 2-(4--hydroxyphenoxy)propanoic acid or an ester thereof with a
substituted pyridine having the requisite substitution in the 3-- and/or 5-ring positions
in addition to 2-halo substitution. The pyridine compound used as starting material
can be prepared from a 2-halopyridine compound, generally the 2-chloro substituted
compound; having trichloromethyl substitution in either or both of the 3- and 5-ring
positions in addition to any desired chloro or bromo substitution at the 3- or 5--positions,
if not occupied by a CC1
3 group, by reacting the pyridine compound with a fluorinating material such as anti-
money trifluoride whereupon the trichloromethyl group or groups are converted to trifluoromethyl
groups.
[0006] The compounds of the present invention wherein T is sulfur similarly can be prepared
by the reaction of 2-(4--mercaptophenoxy)propanoic acid or an ester thereof with an
appropriate substituted pyridine in substantially the same manner as described above.
[0007] The reaction between such a substituted pyridine and the.said hydroxy- or mercapto-phenoxy
propanoic acid can be readily carried out in a polar solvent such as dimethyl sulfoxide
to which has been added a small amount of aqueous or powdered sodium hydroxide. Reaction
is usually carried out at a temperature in the range of about 70 to about 125°C over
a period of about 1 to 3 hours under ambient atmospheric pressure. The reaction mixture
is then allowed to cool and is poured into a quantity of cold water and acidified
with hydrochloric acid, whereupon the product precipitates and is separated and purified
as may be required.
[0008] The propanoate esters of the present invention may be prepared in substantially the
same manner as set forth above for the propanoic acids, using the requisite ester
of 2-(4-hydroxyphenoxy)propanoic acid or 2-(4-mercaptophenoxy)--propanoic acid to
react with the appropriately substituted 2-halopyridine. Or, if desired, the appropriate
propanoic acid of the invention is esterified by first converting to the acid chloride
with thionyl chloride and then reacting the acid chloride with the appropriate alcohol,
or, mercaptan, such as ethyl mercaptan, propyl mercaptan, or butyl mercaptan, according
to generally accepted procedures or the classic method of reacting an alcohol and
an acid in the presence of a little sulfuric acid may be followed.
[0009] The propanoic acid compounds of the invention after conversion to the acid chloride
may also be reacted with (a) ammonia to form the simple amide, (b) with an alkyl amine
to form an N-alkyl amide or N,N-dialkyl amide, or (c)' with a methoxy amine to form
the methoxy amide.
[0010] The simple amide serves as preferred starting material for the manufacture of the
nitriles, which are obtained upon reaction of the amide with phosphorous oxychloride.
[0011] The propanoate metal salts are prepared from the propanoic acid form of the compound
by simply reacting the carboxylic acid with the requisite inorganic base, such as
NaOH, KOH, Ca(OH)
2 or Mg(OH)
2. The amine salts are prepared by reacting the propanoic acid compound with the requisite
amine, for example, triethanolamine or trimethylamine.
[0012] The compounds which are substituted propanols are
[0013]
[0014] Esterification of such alcohol is carried out according to methods generally known
in the art in which, e.g., an acid chloride is reacted with the alcohol in solvent
medium in the presence of a hydrogen chloride acceptor, such as triethylamine. The
hydrochloric salt is filtered off and the solvent stripped, leaving an oily product.
[0015] Ethers of the alcohols of the invention are prepared _by reacting the alcohol with,
e.g., sodium hydride in a polar solvent such as dimethyl formamide at a temperature
of about 35 to 60°C, after which an alkyl bromide is added to the reaction mixture
and heated to 75 to 100°C for one to two hours. The solvent medium is then stripped
off under reduced pressure and the crude product is poured into cold water and final
product taken up with water immiscible solvent such as heptane. The solvent, on being
stripped off, leaves an oily product.
[0016] In an alternate process for making the present propanoic acid compounds, a salt,
e.g.. the sodium salt, of 4-methoxyphenol, or of 4-mercaptophenol, is dissolved in
a solvent such as dimethyl sulfoxide and the requisite trifluoromethyl-substituted
2-chloropyridine is added to the solution of the methoxy phenol and reacted in the
presence of aqueous sodium hydroxide at a temperature in the range of about 70 to
130°C and over a time interval of about 30 to 45 minutes. -The reaction mixture is
then cooled and poured over ice. The solid product is filtered off, washed with water,
taken up in a solvent mixture and reprecipitated therefrom. The methoxy group, if
present, is then cleaved off the phenyl ring by refluxing the compound in'48% by weight
HBr for about an hour and after purification, precipitated from acidic solution and
recovered, as by filtration, and dried. The 4-(trifluoromethyl-substituted 2-pyridyloxy)phenol,
or 4-(trifluoromethyl-substituted 2-pyridylthio)phenol, is then dissolved in a solvent
such as dimethyl sulfoxide, anhydrous powdered sodium hydroxide is added thereto and
reacted therewith for a few minutes at about 75 to 85°C. Then an ester, such as the
ethyl ester of 2-bromopropanoic acid is added to the reaction mixture and stirred
for a time, such as about half an hour, at approximately 100°C or up to about 2 hours
in the case of the sulfur bridged compound. The reaction mixture is then allowed to
cool and poured over ice or simply into cold water whereupon an oily layer separates
which can be recovered by taking up in a water-immiscible solvent and subsequently
stripping the solvent off leaving an oily product. The product so obtained will be
the alkyl ester of the propanoic acid compound. In carrying out the several reactions
of this alternate process, the reactants are usually mixed with a carrier medium,
such as, for example, methyl ethyl ketone, methyl isobutyl ketone or an aprotic polar
solvent such as dimethylformamide, dimethylacetamide,- dimethylsulfoxide, N-methylpyrrolidone,
hexamethylphosphoramide, or sulfolane. The first step condensation is generally carried
out at a temperature of at least 50°C, preferably about 70 to about'150°C and during
a reaction period of about 1 to about 20 hours, preferably about 1 to about 10 hours.
The second condensation reaction is carried out under similar reaction conditions
except that the reaction
Ring Substituents On Pyridine
Example 2
[0017]
[0018] The product had the following elemental analysis:
[0019] These results confirm the obtention of methyl 2-[4-( 3, 5-bis ( trifluoromethyl)
-2-pyridyloxy) phenoxyl propanoate .
[0020] Other compounds of the present invention were similarly prepared by employing procedures
analogous to those set forth in the above example. Such other active ingredients include
the following compounds:
Example 3
[0021] To 5.0 g
trifluoromethyl-2-
30 ml of SOCl
2 and the mixture
minutes, after which unreacted SOCl
2 was removed on a still under water aspirator vacuum. The resulting syrup was added
to a stirred. solution of 30 ml (0.028 mole) of concentrated aqueous NH
40H in 40 ml of acetonitrile. The mixture was stirred at a temperature of 25°C for
15 minutes and filtered, thus recovering crystals of solid product which had formed.
The recovered crystals had a melting, temperature of 140-42°C. On elemental analysis,
the crystals were found to contain 49.50% carbon; 3.44% hydrogen; 10.01% chlorine;
and 7.76% nitrogen. Theoretical composition for 2-[4-(3-chloro-5-trifluoromethyl-2-pyridyloxy)phenoxylpropionamide
is 49.94% carbon; 3.35% hydrogen; 9.83% chlorine; and 7.76% nitrogen.
[0022] Other propionamides of the invention prepared using procedures similar to the foregoing
are as follows.
Example 4
[0023] 2- [4- (5-Chloro.-3-trifluoromethyl-2-pyridyloxy) - phenoxy]propionamide (4.5 g;
0.01248 mole) was refluxed with 20 ml of phosphorous oxychloride for 1.75 hours. The
POC1
3 was distilled off, and the remaining reaction mixture was poured over ice and extracted
with heptane. On cooling, a crystalline product was obtained having a melting range
of 61.5-62.5°C. The anticipated product was 2-[4-(5-chloro-3--trifluoromethyl-2-pyridyloxy)phenoxy]propionitrile.
The following elemental analysis was obtained:
[0024] Other active nitrile compounds similarly prepared include the following.
ExampLe 5 .
[0025] In eich of a series of metal salt preparations 60 milligrams of one of the propanoic
acids of the invention was stirred into several milliliters of water and an aqueous
solution of base added thereto in the amount needed for neutralization plus a slight
excess estimated to be 10% excess upon obtaining a color change to yellow-green in
universal indi atoro The propanoic acids, the molar amount employed, the bases employed
and the estimated amounts of such bases are tabulated as follows, the propanoic acid
being identified by Lng substitution on the pyridyl ring:
[0026] The aqueous solutions so obtained are conveniently used in herbicid applications
with or without further dilution. The
a may be recovered by evaporation of the water from the sections and purified by
careful recrystallization, if desired.
[0027] Magnesium and calcium salts are prepared in substantially the manner decribed above.
Example 6
[0028] to be reached upon titrating to the yellow-green color of universal indicator. The
propanoic acids, identified by ring substituents, the molar amount of propanoic acid,
the base employed and the estimated amounts of each base, are as follows:
[0029] The aqueous solutions so obtained are conveniently used in herbicidal applications
with or without further dilution. The salts may be recovered by evaporation of water
from the solutions and purified by recrystallization, if desired.
[0030] Other amine salts, such as the triethanolamine, diethanolamine, tripropylamine, or
the butylamine salt, are prepared in substantially the manner described above.
Example 7
[0031] Sodium borohydride (6.35 g; 0.1716 mole) was dissolved in 25 ml of water and added
over a ten minute period to a solution of methyl 2-[4-(3,5-bis(trifluoromethyl)-2--pyridyloxy)phenoxy]propionate
(11.7 g; 0.02859 mole) dissolved in 155 ml of warm methanol. During the addition,
the temperature was kept between 25 and 30°C. The mixture was stirred at room temperature
for 40 minutes and was then
tilled off, leaving an orange colored oil with an index of refraction of 1.5028
at 25°C. The anticipated product was 2-[4-(3,5-bis(trifluoromethyl)-2-pyridyloxy)phenoxy]propanol.
The product had the following elemental analysis:
[0032] 2-[4-(3-Chloro-5-trifluoromethyl-2-pyridyloxy)-phenoxy]propanol, 1.5377, was prepared
by similar procedure. Elemental analysis:
Example 8
[0033] 2-[4-(3,5-Bis(trifluoromethyl)-2-pyridyloxy)phenoxy]-propanol (5.45 g; 0.0171 mole)
was dissolved in 75 ml of toluene and placed in a round bottom flask, and 1.8 g of
triethylamine was added thereto. Then octoyl chloride (3.05 g; 0.01875 mole) as a
solution in 18 ml of toluene was added to the propanol over a 3-minute period at a
temperature of 25-30°C. The mixture was stirred for about an hour at ambient room
temperature and then refluxed for about one hour. At the end of the reaction period,
the separated hydrochloride salt was filtered off, and the toluene was stripped off.
The-residue was poured into ice water and extracted with heptane. The heptane extracts
were dried, and the heptane was removed by distillation, leaving an oil with a refractive
index of 1.4740 at 25°C. The anticipated product was 2-(4-(3,5-bis(trifluoromethyl)-2-pyridyloxy)phenoxy]propyl
octanoate. The product had the following elemental analysis:
[0034] 2-[4-(3-Chloro-5-trifluoromethyl-2-pyridyloxy)-phenoxy]propyl acetate, .1.5230, was
prepared by similar procedure. Elemental analysis:
Example 9
[0035] Sodium hydride (0.8 g; 0.0334 mole) is dissolved in 30 ml of dry dimethyl formamide,
and then a solution of 2-[4-(3, 5-bis (trifluoromethyl) -2-pyridyloxy)phenoxy] propanol
(5.5 g; 0.0176 mole) in 50 ml of dry dimethylformamide is added to the sodium hydride
solution over a four-minute period and then stirred for an hour at 40-50°C. A solution
of l-bromobutane (2.4 g; 0.0175 mole) in 25 ml of dry dimethy formamide is then added
over a six-minute period. The reaction mixture is then slowly heated to 90°C over
a 30-minute period and held at 90°C for one hour and ten minutes. The reaction mixture
is then stirred and heated at 105-115°C for 2 hours. The dimethylformamide is then
strippe off under partial vacuum and the crude product poured into cold water and
extracted with heptane. The heptane is remove by distillation, leaving an oil, 2-[4-(3,5-bis(trifluoromethyl)-2-pyridyloxy)phenoxy]propyl
n-butyl ether.
Example 10
[0036] The following series of preparations illustrate an alternate method of synthesizing
the propanoate esters and from such compounds the propanoic acids of the invention.
A solution of the sodium salt of 4-methoxyphenol was prepared by dissolving the methoxyphenol
(7.45 g; 0.06 mole) in 45 ml of dimethylsulfoxide and adding a solution of sodium
hydroxide (2.4 g; 0.06 mole) in 7 ml of water. A solution of 2-chloro-5-(trifluoromethyl)pyridine
(9.0 g; 0.05 mole) i 40 ml of dimethylsulfoxide was then added to the above sodiu
phenate solution over an 11 minute period. During-the addition, the temperature rose
to about 80°C, and then the reaction mixture was heated to 124°C over 26 minutes and
the temperature maintained for 15 minutes. At the end of this time, the reaction mixture
was cooled to 75°C and poured over ice. The solid product was collected on a filter,
washed, and taken up in a toluene-hexane mixture. This solution on cooling yielded
9.7 grams of solid product having a melting temperature of 49.5-50.5°C and having
a composition of 58.02% carbon; 3.86% hydrogen; and 5.22% nitrogen. The theoretical
composition is 57.99% carbon; 3.74% hydrogen; and 5.20% nitrogen, confirming the product
to.be 5-(trifluoromethyl)-2-(4-methoxyphenoxy)pyridine.
[0037] The 5-(trifluoromethyl)-2-(4-methoxyphenoxy)pyridine , (10.95 g; 0.0407 mole) was
refluxed with 50 ml of 48 percent by weight aqueous hydrobromic acid solution for
one hour. At the end of this time, the reaction mixture was cooled, poured over ice
and the separated solids collected on a filter. The product was purified by taking
it up in dilute caustic solution, extracting the solution with chloroform to remove
unreacted starting material and then acidifying the solution to precipitate free phenol.
The dried crystalline phenol product had a melting temperature of 89-91°C and was
found to contain 56.21% carbon; 3.27% hydrogen; and 5.44% nitrogen. The theoretical
composition of 4-(5-trifluoromethyl-2-pyridyloxy)phenol is 56.48% carbon; 3.16% hydrogen;
and 5.49% nitrogen.
[0038] The 4-(5-trifluoromethyl-2-pyridyloxy)phenol (4.95 g; 0.0194 mole) was dissolved
in dimethylsulfoxide (41 ml); then sodium hydroxide (0.78 g; 0.014 mole) was added
as a dry powder and the mixture stirred for about 10 minutes and warmed to about 80°C.
Ethyl 2-bromopropionate (4.2 g; 0.023- mole) was then added and the mixture stirred
for about 35 minutes at 96°C. The solution was then cooled, poured over ice and the
oil, which separated, taken up in petroleum ether containing 20 percent by volume
methylene chloride. The separated solvent phase was stripped of solvent leaving an
oily product weighing 6.3 g. An infrared scan of a sample of the oil confirmed the
ester structure of the anticipated ethyl 2-[4-(5-trifluoromethyl-2-pyridyloxy)phenoxy]propionate.
[0039] Ethyl 2-[4-(5-trifluoromethyl-2-pyridyloxy)phenoxy]-propionate (6.3 g; 0.0177 mole)
was dissolved in 28 ml of ethanol, and a solution of sodium hydroxide (1.06 g; 0.0266
mole) in 28 ml of water was added. The reaction mixture was heated to 75°C for 5 minutes
and then poured into 150 ml of cold water and acidified with 4 g of concentrated hydrochloric
acid. The crude acid product, which precipitated, was washed with hot petroleum ether
and dried. The resulting product had a melting temperature of 97-100°C and was found
on analysis to contain 54.91% carbon; 3.77% hydrogen; and 4.28% nitrogen. The theoretical
composition for 2-[4-(5-trifluoromethyl-2-pyridyloxy)phenoxy]propionic acid is 55.05%
carbon; 3.70% hydrogen; and 4.28% nitrogen, indicating the' expected product was obtained.
Example 11
[0040] 4-Mercaptophenol (7.6 gm., 0.06 mole) was dissolved in 70 ml of dimethyl sulfoxide,
and a solution of sodium hydroxide (2.4 gm.,. 0.6 mole)'in 3.0 ml of water was added.
The mixture was warmed to 50° and stirred under nitrogen for 10 minutes to form the
sodium thiophenate salt. A solution of 2-chloro-5-(trifluoromethyl)pyridine (10.9
gm., 0.06 mole) in 60 ml of dimethylsulfoxide was then added all at once. The mixture
was heated to 100° and held there for 1.5 hours. At the end of this time it was poured
into 500 ml of cold water. An emulsion formed; therefore, 60 ml of a saturated solution
of ammonium chloride was added. The product precipitated as a sticky solid. The aqueous
layer was decanted, the solid washed with more water then taken up in hot heptane,
dried with solid sodium sulfate and decolorized with charcoal. In the filtrate, a
white solid product precipitated and was separated and found to have a melting temperature
of 89-93°C.
[0041] The so-prepared 4-[5-(trifluoromethyl)-2-pyridyl- thio]phenol (10 gms., 0.037 mole)
was dissolved in 80 ml of dimethylsulfoxide, and dry, powdered sodium hydroxide (6.7
gm., 0.37 mole) was added. The mixture was warmed to about 40° and stirred until the
base was all in solution indicating that the desired sodium phenate had formed. Ethyl
bromopropionate (6.7 gm., 0.37 mole) was then added all at once. The reaction was
run at 100-105° for 2.0 hours, then cooled and poured into 450 ml of cold water. The
ester was extracted into methylene chloride, the extract dried and solvent removed
leaving the product as an'oil weighing 13.5 gm.
[0042] This was used without further purification for the next step which was hydrolysis
of the ester to the metal salt in aqueous alkaline medium.
[0043] The ethyl 2-[4-(5-trifluoromethyl-2-pyridylthio)-phenoxy]propionate (13.5 gm., 0.37
mole) was dissolved in 50 ml of 95% ethanol and a solution of sodium hydroxide (3.0
gm., 0.075 mole) in 25 ml of water was added. The mixture was refluxed at 80° for
about 6 minutes, then cooled, poured into 400 ml of cold water, and extracted with
250 ml of methylene chloride to remove any base-insoluble impurities. The aqueous
solution containing the sodium salt of the acid was acidified to pH 1 with concentrated
hydrochloric acid. The product which precipitated as a gummy solid was washed with
water (after decanting) and taken up in hot methylcyclohexane. On cooling, the product
precipitated as white crystals having a meltingtemperature of 118-120°C and a composition
of, by weight, 52.38% carbon; 3.66% hydrogen; 4.00% nitrogen and 9.07% sulfur. The
theoretical composition of 2-[4-(5-trifluoromethyl-2-pyridylthio)phenoxy]propanoic
acid is 52.5% carbon; 3.5% hydrogen; 4.08% nitrogen and 9.34% sulfur.
Example 12
[0044] 4-Mercaptophenol (6.4 gm., 0.051 mole) was dissolved in 70 ml of dimethylsulfoxide
and a solution of sodium hydroxide (2.04 gm., 0.051 mole) in 3.0 ml of water was added..
The mixture was warmed to about 50° and stirred under nitrogen for 10 minutes to form
the sodium thiophenate salt. A solution of .2, 3-dichloro-5- (trifluoromethyl) pyridine
(11.0 qm., 0.051 mole) in 60 ml of dimethylsulfoxide was next added at once. The mixture
was then heated at 95-100° efor 2.5 hours, then poured into 500 ml of cold water and
allowed to stand for 45 minutes. The solid was then collected on a filter, washed
and taken up in about one liter of boiling hexane. The product precipitated on cooling
as a white solid melting at 94-96°C.
[0045] The so-prepared 4-[3-chloro-5-trifluoromethyl-2-pyridylthio]phenol '(11.0 gm., 0.036
mole) was dissolved in 80 ml of dimethylsulfoxide and dry powdered sodium hydroxide
(1.44 gm., 0.036 mole) was added. The mixture was warmed and stirred until the base
was all in solution, showing that the desired sodium phenate had formed. Ethyl bromopropionate
(6.5 gm., 0.036 mole) was then added all at once. The reaction was run at 100° for
2.0 hours, then cooled and poured into 500 ml of water. Most of the product precipitated
as a white semi-solid. The aqueous layer, which was decanted off was extracted with
300 ml of methylene chloride. The extract was separated, solvent removed, and the
residue added to the
Example 13
[0046]
Example 14
[0047] A mixture of 60 ml of thionyl chloride and 6.0 g of 2-[4-(3-chloro-5-trifluoromethyl-2-pyridyloxy)phenoxy]-propanoic
acid was refluxed for 30 minutes. The excess thionyl chloride was removed on a still
using aspirator vacuum. The resulting acid chloride was dissolved in 25 ml toluene.
This solution was then added to a reaction flask containing 2.1 g 2-butoxyethanol,
1.85 g triethyl amine, and 27 ml toluene and the mixture refluxed for about 2 hours.
The salt was filtered off and the volatiles removed. The crude product was taken up
in n-hexane, purified with activated carbon, and the hexane removed. 7.05 G of amber
oil was obtained which had a refractive index of 1.5061 at 25°C and an elemental analysis
of: C = 54.27%; H = 4.97%; N = 3.21%; and Cl = 7.77%. Calculated values for 2-[4-(3-chloro-5-trifluoromethyl-2-pyridyloxy)phenoxy]propanoic
acid, 2-butoxyethyl ester are: C = 54.61%; H = 5.028; N = 3.038; and Cl = 7.68%.
Example 15
[0048] A mixture of 80 ml of thionyl chloride and 8.0 g of 2-[4-(3-chloro-5-trifluoromethyl-2-pyridyloxy)phenoxy]-propanoic
acid was refluxed for 3.8 minutes. The excess thionyl chloride was then removed on
a still using aspirator vacuum. The resulting acid chloride was dissolved in 30 ml
toluene. This solution was then added to a reaction flask containing 2.1 g of butyl
mercaptan, 2.5 g of triethyl amine, and 25 ml of toluene. The mixture was slowly heated
to 98°C over one hour and then refluxed for about 45-50 minutes. The salt was filtered
out and the volatiles removed. The
2-[4-(3-chloro-5-trifluoromethyl-2-pyridyloxy)phenoxy]thio- propanoic acid S-butyl
ester is: C = 52.59%; H = 4.41%; N = 3.23%; Cl = 8.17%; and S = 7.39%.
[0049] The compounds of the present invention have been found to have advantage over prior
art compounds in the control of perennial grassy weeds in that the present com- -
pounds control a broader spectrum of such weeds than the counterpart compounds while
exhibiting a higher level of activity or control at-like dosage rates. In addition,
the present compounds are sufficiently tolerant towards most broad leafed crops to
contemplate control of grassy weeds therein at substantially commercially practicable
levels, particularly so with the preferred compounds.
[0050] For such uses, unmodified active ingredients of the present invention can be employed.
However, the present invention embraces the use of the -compounds in composition form
with an inert material known in the art as an adjuvant or carrier in solid or liquid
form. Thus, for example, an active ingredient can be dispersed on a finely-divided
solid and employed therein as a dust. Also, the active ingredients, as liquid concentrates
or solid compositions comprising one or more of the active ingredients can be dispersed
in water, typically with aid of a wetting agent, and the resulting aqueous dispersion
employed as a spray. In other procedures, . the active ingredients can be employed
as a constituent of organic liquid compositions, oil-in-water and water-in-oil emulsions
or water dispersions, with or without the addition of wetting, dispersing, or emulsifying
agents. Suitable adjuvants of the foregoing type are well known to those skilled in
the art.
[0051] The concentration of the active ingredients in solid or liquid compositions generally
is from about 0.0003 to about 95 percent by weight or more. Concentrations from about
0.05 to about 50 percent by weight are often employed. In compositions to be employed
as concentrates, the active ingredient can be present in a concentration from about
5 to about 98 weight percent. The active ingredient compositions can also contain
other compatible additaments, for example, phytotoxicants, plant growth regulants,
pesticides and the like and can be formulated with solid particulate fertilizer carriers
such as ammonium nitrate, urea and the like.
[0052] The present compounds which are substituted propanol or propyl ethers are more effective
in preemergent operations than in postemergent applications.
[0053] The exact rate to be applied is dependent not only on a specific active ingredient
being applied, but also on a particular action desired (e.g., general or selective
contro] the plant species to be modified and the stage of growth thereof as well as
the part of the plant to be contacted witl the toxic active ingredient. Thus, all
of the active ingredients of the present invention and-compositions containing the
same may not be equally effective at similar concentrations or against the same plant
species. In non--selective preemergence and foliar treatments, the active ingredients
of the invention are usually applied at an approximate rate of from about 0.5 to about
5 pounds/acre (0.56-5.6 kg./hectare), but lower or higher rates may be appropriate
in some cases such as 0.01 to about 20'pounds/ac (0.011-22.4 kg./hectare). In preemergent
operations for selective uses a dosage of about 0.05 to about 20 pounds/acr (0.056-22.4
kg./hectare) is generally applicable, a rate of 0.2 to 4 pounds/acre (0.224-4.48 kg./hectare)
being preferre and about 0.75 to about 1 pound/acre (0.84-1.12 kg./hectare) being
most preferred.
[0054] In selective postemergent operations a dosage: of about 0.01 to about 20 pounds/acre
(0.011-22.4 kg./hectar is generally applicable, although not all compounds and equally
effective and some weeds are more difficult to control. Thus, a dosage rate in the
range of about 0.05 to about 0.75 pounds/acre (0.056-0.84 kg./hectare) is preferr
in postemergent control of annual grassy weeds, while above 0.5 to about 5 pounds/acre
(0.56-5.6 kg./hectare) is a preferred dosage range for the postemergent control of
perennial grassy weeds.
[0055] The following examples illustrate effects of the compounds of this invention. Plant
species used in these tests were the following.
Example 16
Example 17
[0057] To illustrate the phytotoxic properties of the various active ingredients of the
present invention in post emergent application, a group of controlled greenhouse experiments
is described below.
[0058] Various species of plants were planted in beds of good agricultural soil in a greenhouse.
After the plants had emerged and grown to a height of about 2-6 inches (5-15cm ) a
portion ofthe plants were sprayed with an aqueous mixture made by mixing a selected
active ingredient and emulsifier or dispersant with about 1:1 water-acetone, employing
sufficient amounts of the treating composition to provide application rates of 4000
parts per million (ppm) or about 10 pounds per acre (11.2 kg/hectare) and in some
cases so
Other portions of the plants were left
to serveas controls.
Example 18
[0060] In a series of tests clearly demonstrating the herbicidal properties of the compounds
of the present invention applied in postemergent application, various metal and amine
salts of propancic acids prepared in aqueous solution as described hereinabove and
brought initially to a dilution of 4000 ppm were applied to growing plants under greenhouse
conditions.
[0061] Various species of plants were planted in pots containing good agricultural soil
in a greenhouse. After the plants had emerged and grown to a height of about 2-6 inches
(5-15 cm.), some of the plants were sprayed, respectively, with a respective one of
the said aqueous solutions then diluted and sprayed on other respective selected plants
at lower rates, each species of plant not being run at all rates. Other plants were
left untreated to serve as controls. Still other plants, plants of Bermuda grass,
blue grass, Johnscn grass and cheat grass, were allowed to crow to 6-8 inches (15-20
cm.) then four times cut back to 2 inches (5 cm. ) and allowed to regrow, all over
about a 6-7 week period providing established plants.
[0062] After about two weeks, the effect of the respective test ingredients used on various
respective plants was evaluated by comparison with the control group of plants. The
results showed that the potassium and triethylamine salts of 2-[4-(5-trifluoromethyl-3-chloro-2-pyridyloxy)phehoxy]-propanoic
acid applied (a) at a rate of 4000 ppm gave complete control of Bermuda grass, vorghum
and barnyard grass while showing little or no control of cottons (b) at a rate of
2000 ppm gave substantial to complete control of bluegrass and rice while showing
no effect on soybeans; (c) at a rate of 1000 ppm gave complete control of Johnson
grass , crabgrass and yellow foxtail; and (d) at a rate of 500 ppm exhibited complete
control of cheat grass, corn, wheat and wild oats.
control of wild oats, foxtail, barnyard grass cotton, pigweed, annual morning glory
orvelver leaf, while
-dimethyl-2-[4-(5-trifluoromethyl-2-pycidyloxy)phenoxy]-propanamide showed complete
control or wild oats, foxtail barnyard grass and crabgrass.
[0063]