CA1078407A - M-isopropyl phenylureas - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Compounds of the structural formula in which R is from the group consisting of hydrogen, methyl, ethyl and methoxy; m and n are integers from 0 to 3; and X
is hydrogen when the sum (m+n) exceeds 4, otherwise X is from the group consisting of H, F, and Cl. The compounds possess herbicidal properties and are particularly effective in post-emergence weed control.

Description

~784~)'7 R.J.~immons et al 2-2-2 This invention relates to m-isopropyl phenylureas, to a process for the control of undesirable vegetation with said compounds and to herbicidal compositions containing said compounds.
m-alkyl phenylureas in which the alkyl group is methyl or halosubstituted methyl are known, as is their herbicidal activity. Specifically, the trifluoroemthyl derivative is sold commercially as a herbicide. However, the trifluoromethyl derivative has a broad spectrum of activity and damages many desirable crops including established lawns.
It is, therefore, insufficiently selective to use for weed ' control of lawns. German patent 1,911,610, dated October 1, 1970, discloses a group of polyhaloethyl and -propyl derivatives possessing herbicidal activity with greater selectivity.
However, the patent discloses only pre-emergence herbicidal activity and neither the German patent, nor the prior art, discloses how the propyl derivatives are prepared. Moreover, the degree of herbicidal effectiveness of the known m-alkyl phenylureas appears to decrease as the fully halogenated alkyl group increases in length from methyl through propyl. The trifluoromethyl is the most effective herbicide, the fully fluorinated ethyl derivative is not as effective and the isopropyl derivatives disclosed in the German patent possess insufficient herbicidal activity to be of value for weed ~5 control.

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` iO78407 .
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R.J. Timmons et al 2-2-2 :' It is, therefore, a primary object of the present invention to provide a new class of m-isopropyl phenylureas.
It is an additional object of this invention to provide a new class of herbicidal compounds for the post-emergence control of weeds, and more specifically for theselective post-emergence control of monocot weeds in lawn~.
;` It has now been discovered that compounds of the . ~
following structural formula are effective herbicides for post-emergence weed control:

'`''` 10 >N C NH= ~_ R ~ CFnH3-n ~ FORMULA I

! CFm~3_m in which R is from the group consisting of hydrogen, methyl, ethyl and methoxy; m and n are integers from 0 to 3; and X is hyarogen when the sum (m+n) exceeds 4, and otherwise X is from the group consisting of H, F, and Cl. The compounds of ;j the invention are used by applying a growth inhibiting amount to undesirable vegetation, including both monocotyledonous and dicotyledonous weeds. They are particularly useful for the selactive post-emergence control of monocotyledonous weeds in lawns.

Control of standing dicot weeds in grass lawns can be readily effected by application of known herbicides. However, .

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` 1C~78407 R. J. Timmons et al 2-2-2 ,;
such control is not presently avaiLable for emerged monocot weeds in lawns. Probably the most successful instance of salective grass control is post-emergence control of crabgrass with derivatives of methanèarsenic acid. But the use of such materials has come under increasing attack on ecology grounds.
Insofar as is known, no satisfactory material is available for the selective post-emergence control of tall fescue, bentgrass, ; poa annua, nimblewill, or quackgrass in lawns.
The m-isopropyl phenylureas of the above Formula I
possess high activity against many of these noxious monocotyl-edonous weeds whilP maintaining tolerance to desirable lawn grasses. The present compounds therefore, offer to fulfill the long-sought goal of post-emergence control of monoctyledonous weeds in grass lawns.
Examples of compounds falling within Formula I which have been found to be useful in the invention include the following~
1. Compounds in which X is hydrogen and m and n are each three:
\N _ C _ NH ~ O ~

" 3 2 l-Methyl-3-m-(1,1,1,3,3,3-hexafluoro-2-propyl) phenylurea 1,1-Dimethyl-3-m-tl,1,1,3,3,3-hexafluoro-2-propyl) phenylurea l-Methoxy-l-methy1-3-m-(1,1,1,3,3,3-hexafluoro-2-propyl)-phenylurea . .

.

Q78~)7 ''' R. J. Timmons et al 2-2-2 l-Ethyl-l-methyl-3-_-(1,1,1,3,3,3-hexafluoro-2-propyl)-phenylurea ~- 2. Compounds in which X is fluorine and m and n are . each two:

C~
. CF(C~IF2)2 ~ .
` l-Methyl-3-_-(1,1,2,3,3-pantafluoro-2-propyl)phenylurea, . 1,1-Dimethyl-3-m-(1,1,2,3,3-pentafluoro-2-propyl)phenylurea, and ; 10 1-Methoxy-l-Methyl-3-_-~1,1,2,3,3-pentafluoro-2-propyl)-phenylurea.

3. Compounds in which X is chlorine and m and n ~ are each two:

:: CH3 o / N C WH - ~

: CCl (CHF2)2 .
l-Methyl-3-m-(2-Chloro-1,1,3,3-tetrafluoro-2-propyl)phenylurea, 1,1-Dimethyl-3-m-(2-chloro-1,1,3,3-tetrafluoro-2-propyl)-phenylurea, 20 . 1-Ethyl-l-methyl-3-m-(2-chloro-1,1,3,3-tetrafluoro-2-propyl)-phenylurea, and l-Methoxy-l-methyl-3-m-(2-chloro--1,1,3,3-tetrafluoro-2-propyl)-phenylurea.

` ~C378407 .:
R. J. Timmons et al 2-2-2 4. Compounds in which X is fluorine, m is 0 and n is three:
C}13 "
N C____NH < ~ O~ ~

CF'' 3 \ CH3 l-~ethyl-3-m-(l,l,l,2-tetrafluoro-2-propyl) phenylurea, Dimethyl-3-mr(1,1,1,2-tetrafluoro-2-propyl) phenylurea, and l-Methoxy-l-methyl-3-m~l,l,~tetrafluoro-2-propyl)phenylurea.
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5. Compounds in which X is hydrogen and m and n -~ lO are 0: o \ N - C NH - ~ O ~

C11 (C~13)2 l-Methyl-3-m-(2-propyl) phenylurea, l-l-Dimethyl-3-m-(2-propyl) phenylurea, and l-Methoxy-l-methyl-3-m-(2-propyl) phenylurea.
. .
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of the foregoing compounds, the most active appear to be the l,l-dimethylureas (in which R is methyl).
The unobvious nature of the present discovery is :. .
demonstrated by the lack of herbicidal activity shown by a number of closely related compounds. The compounds falling within the scope of Formula I generally demonstrate 80~ or ; ~ ~
' ~ -6-. . !

~ ~ . ' ' , ' ' `

-` ` `` ~.~3784(~
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R. J. Timmons et al 2-2-2 - 7 ~

greater control of several indicator weeds at 5 ox 10 lbs per acre and often control one or more weeds at 1 lb/acre. The following closely related compounds failed to give as much as -` 50% control of a single weed species at either 5 or 10 lbs/acre:
O
N C N ~
; CX (CF3)2-in which R=CH3 and X=OCH3; R=CH3 and X=F; R=OCH3 and X=F;
and R=CH3 and X=Cl, and CH3 ~
R ~ ~ C
F ICClF2)2 in which R=CH3 or OCH3.
me compounds of the invention are prepared from the corresponding m-isopropylaniline intermedia~e, many of which are themselves new compounds. The latter compounds and their preparation are the subject of our co-pending Canadian ~pplication No. 195,128 filed of even date herewith and reference should be i 20 made to tha foregoing application for a complete description of ~he preparation of the intermediates. In general, the m-isopro-pylanilines are pxepared by reacting benzene in the presence of a metal halide catalyst with a ketone of the formula:

CFnH3_n Cl-O
CFmH3_m - 1~7~3407 .

R. J. Timmon~ et al 2-2-2 in which m and n are integers from 0 to 3 to produce a 2-phenyl isopropanol, halogenating the 2-phenyl isopropanol to produce a 2-halo-isopropyl benzene, nitra~ing the 2-halo-isopropyl benzene to produce a m-(~-halo-isopropyl) nitro-benzene, and hydrogenating the m-(2-halo-isopropyl) nitro-benzene to produce the m-isopropylaniline intermediate. The phenylureas are produced from the m-isopropylanilines by converting the latter -~ with phosgene to isocyanates which readily react with aliphatic amines to produce the ureas.
The following examples illustrate the preparation of the phenylurea compounds of the invention. Examples 1-5 illustrate the preparation of the isocyanate, while examples 6-22 illustrate the preparation of the final phenylurea com~
pounds from the isocyanate.

Example 1 The following procedure was used in the preparation of each of the isocyanates of Examples 1-5 from the isopropyl-aniline.
A phosgene cylinder was connected to a trap and in turn to a gas addition tube entering the reaction flask. This flask was equipped with a mechanical stirrer, thermometer, and condenser which was replaced with a dropping funnel during the . : . . ~ . , ~ .

~78407 R. Jo Timmons et al 2-2-2 _9_ addition of isopropylaniline. The top of the condenser (or . dropping funnel) was equipped with an adaptor. The adaptor was ~ ~a6~ k~
~ connected via Tygon~tubing through a trap to a magnetically-stirred solution of 30~ NaOH. Ethyl acetate was dried over MgSO4, and a 2-liter portion was employed per mole of isopropyl-aniline reagent. The isopropylaniline was dissolved in 5 ml.
of ethyl acetate per gram, and the remaining ethyl acetate was placed in the reaction 1ask.
The phosgene stream was started and the ethyl acetate in the reaction flask saturated at room temperature ~pproxi-mately 20 minutes). The condenser was replaced with a dropping funnel containing the solution of isopropylaniline in ethyl acetate. The isopropylaniline was added dropwise while the phosgene stream was continued. After the addition was complete, the dropping funnel was replaced and heat was applied until gentle reflux was attained. In each case, l hour of ref~ux while phosgene addition was continued was sufficient to convey any insoluble amine hydrochloride into the soluble isocyanate.
The phosgene stream was stopped, and dry nitrogen was passed ao through to remove most excess phosgene while the solution was refluxed for a second hour. After the solution had cooled, the bulk of the solven~ was removed by distillation with aspirator vacuum. The remainder of the solvent was removed with a rotary evaporator to leave the crude produc~. The 1~78407 R. ~. Timmons et al 2-2-2 specific isorpopylaniline used in this example was m-(l,l,l-3,3,3-hexafluoro-2-propyl) aniline. The reaction product was O=C=N ~
C}~(CF3)2 m~(l~ 3~3~3-Hexafluoro-2-propyl) phenyl Isocyanate Liquid, b.p. 114-124C. (45 mm). IR: 4.38~ (N=C-O).
The same procedure was used to prepare the follow-ing isocyanates from the corresponding isopropylanilines.

Example 2.

O=C=N_ ~
CF(CHF2)2 m-(1,1,2,3,3-Pentafluoro-?-propyl) phenyl Isocyanate ~iquid, b.p. 115-120C. (15 mm). IR: 4.38~ (N-C-O).

Example 3.
O=C=N ( ~
CCl(CHF2)2 ~-(2-Chloro-1,1,3,3-tetrafluoro-2-pro ~ ) phenyl Icocyanate Clear, colorless liquid, b.p. 132-138C. (llmm). IR: 4.39~J
(N=C=O).

Example 4.
r O-C=N--<~ /CF3 ~ ~13 m- (1, 1 ,1, 2-tetrafluoro-2-propyl)~ nyl Isocyanate Liquid, b.p. 115C. (30 mm.) IR: 4.40~ (N=C=O).

, .

; 1~78407 R. J. Timmons et al 2-2-2 Example 5.
O=C=N- ~
C1~(C113)2 ':....................... .
` m-Isopropylphenyl Isocyanate , Liquid, B.P. 55C. (0.5 mm.). IR: 4.38~ (N-C=O).

Examples 6-22.
The following procedure was used to convert the isocyanate to the final phenylurea compound by reaction with the appropriate aliphatic amine, CH3NRH, where R has the same meaning as in Formula I above.
Methylamine, dimethylamine, and methylethylamine were commercially available reagent grade chemicals. Methoxy-methylamine was generated as ne~eded by covexing its hydro-chloride with 5 ml. of ether per gram and slowly adding l0 lS NaOH to generate a solution of the free amine in ~ther.
In the urea preparations, an excess of amine was employed~ This was to account for loss due to vola~ility of methyl-, dimethyl-, and methylethyl-amine and for lack of complete conversi.on of the methoxy-methylamine hydrochloride to the free amine! in ether.
A solution of the appropriate amine in dry ether was cooled in an ice bath, and a solution of the aryl iso-cyanate in 5 ml. of ether per gram was added dropwise below 10C. After the addition was complete, the reaction mixture was stirred 2 hours at ambient temperature. The condenser was removed, and the ether allowed to evaporate as the reaction ~71~0~

` R. J. Timmons et al 2-2-2 mixture stirred overnight in a hood. The crude pxoduct which remained was purified by appropriate means. Properties of the specific ureas prepared are given in tlle following ~xamples.

; 5 m-(1,1,1,3,3,3-Hexafluoro-2-propyl) phenyl Ureas \ N _ C - NH - ~ ~

H(CF3)2 Analysis Exampla R mp ~C) C=O(cm 1) C H F N

7 CH3 122-123 1630 Calcd. 45.87 3.85 36.28 8.91 Found 45.90 4.78 35.94 9.00 8OCH3 67-72 1660 Calcd. 43.65 3.66 34.52 8.48 Found 43.55 3.48 34.34 8.56 ; 15 m-(1,1,2,3,3-pentafluoro-2-propyl) phenyl Ureas \ N - C - NH - ~
CF(CHF2)2 Analysis Example R mp (C) C-O (cm~l) C H F N
H113-115 1650 Calcd. 46.82 3.90 33.66 9.93 Found 46.98 3.63 33.37 10.22 ` 11 CH395-96 1640 Calcd. 48.66 4.42 32.07 9.46 Found 48.37 4.22 32.62 9.68 12 CH30 oil 1680 Calcd. 46.16 4.19 30.42 8.97 Found 46.20 4.19 29.43 8.76 - - lQ789~7 .
.
,~ R. J. Timmons et al 2-2-2 ; - 13 -m-(2-chloro-1,1,3,3-tetrafluoro-2-~propyl) phenyl ureas CH3 \ "

R ~ { ~
Cl(CHF2)2 ` Anal~sis Example R mp (C) C-0(cm~l) C _ Cl F N
13 H 137-39 1650 Calcd. 44.23 3.71 11.87 25.45 9.38 Found 43.82 4.04 12.33 24.91 9.54 14 CH3 87-88 1640 Calcd. 46.09 4.19 11.34 24.30 8.96 . Found 45.45 4.48 11.14 24.60 9.24 C2Hs 81-83 1640 16 OCH3 Oil 1670 Calcd. 43.85 3.99 10.79 23.12 8.52 Found 43.75 4.44 10.56 22.53 9.04 ~, mr(l,l,l,2-tetrafluoro-2-propyl) phenyl ureas .~: O
~3 ~N- C NH ~ ~ CF3 F
\ GH3 Example R mp (C) C=0(cm~l) C Analysis N
17 H 119-123 1650 Calcd. 50.01 4.57 28.76 10.60 Found 50.20 4.78 28.46 10.80 18 CH3 108-109 1640 Calcd. 51.80 5.07 27.31 10.07 Found 51.50 5.18 27.14 10.17 ; 19OCH3 Oil 1680 Calcd. 48.98 4.79 25.83 9.52 ` Founa 49.10 4.89 26.10 9.32 m-Isopropylphenyl ureas C33 ~ C _ N~3 ~
CH(cH3)2 ;

R. J. Timmons et al 2-2-2 Analysis Example R mp (C~? C=O(cm 1) C H N

21CH3 98-99 1650 Calcd. 69.87 8.80 13.58 E'ound 69.92 8.85 13039 22oc~3 77-78 1670 Depending on the particular compound, the type of formulation in which it is incorporated, the character--~ istics of the particular area to which the formulation is applied, etc., the compounds of the present invention may be applied at single application rates ranging from 1 to 16 or more pounds per acre for the purposes discussed above.
Applications in this range will in most cases provide excellent weed control with minimal or no turfgrass injury.
It is within the province of our invention to use repeat applications of the compounds, normally at rates below the single application rates. Repeat applications at low rates will typically provide control of weeds with a minimum of turf injury in even the most difficult circumstances.
Further, mixtures of the compounds of the present invention may be employed for the purposes described herein, if desired.
The compounds of the present invention can be employed in sprays, in granular formulations, as drenches or combined with a diluent and,/or other adjuvants to make a dust and .

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R. J. Timmons et al 2-2-2 applied with conventional dusting equipment. Depending ; upon factors such as those discussed above in conjunction with application rates, the proportions of the ingredients in the formulation may vary over a wide range. Generally 5 speaking, however, the proportions will fall within the following limits:
Ingredient Parts by Weight Carrier 8100 Solvent-sticking agent 0-3200 Phenyl urea 300-4500 Surfactant 0-1000 Appropriate carriers include organic solvents, water, vermiculite, perlite, diatomaceous earth, clay, corn cobs, and other materials such as those described in the - 15 Handbook of Dust Diluents and Carriers (2d Ed.), 1955. For granular formulations, exfoliated vermiculite is preferred.
` One suitable surfactant for use in the formulations descri~ed herein is Triton X-100, a trademark for an octylphenoxy-polyethoxy ethanol manufactured by Rohm & Haas Company.
Other suitable surfactants are those listed in Deter~ents and Emulsifiers, Up-to-Date, 1968, John W. McCutcheon, Inc.
The "solvent" may include or be a sticking agent. Suitable "solvents" include Polyvis OSH (a trademark for a polybutene having a molecular weight of approximately 400 manufactured by the ,.

. ~078407 R. J. Timmons et al 2-2-2 Cosden Oil and Chemical Company) and hexylene glycol. Other suitable solvents-sticking agents are described in U. S. Patents Nos. 3,076,699 and 3,083,089.
The foregoing patents also disclose methods for making granular formulations which may be used with the compounds of tne present invention. That is, those compounds which are solids at room temperature may be dissolved in an appropriate solvent and adhered to a carrier in the m~nner disclosed in Patent No. 3,083,089. Or particles of the compound may be adhered to a carrier with a suitable s~ick-ing agent as described in Patent No. 3,076,699. Those compounds which are liquids can be similarly absorbed on exfoliated vermiculite as described in the foregoing patents.
Diluents, stabilizers, fertilizers and other plant nutrients, other herbicides, flow enhancing agents, adhesives, dyes, and other adjuvants may also be employed in formulations in which the compounds of the present invention are incorporated. The above mentioned and other adjuvants which may be employed are described in Weed Control ~2d Ed.), Robbins et al, McGraw-Hill Book Company, Inc., New York, New York, 1952, and in U. S. Patents No. 3,231,363, issued January 25, 1966, to Victor A. Renner for PROCESS
FOR MAXING FOAMED UREA-FORMALDEHYDE FERTILIZER, and U. S.
Patent 3,705,794, issued December 12, 1972 for FOAMED

FERTILIZERS AND COMBINATION PRODUCTS which disclose various 107840~

R. J. Timmons et al 2-2-2 com'oination prod~cts in which the compounds disclosed herein may be incorporated and methods of preparing such formulations. tSee also Patents Nos. 3,076,699 and 3,083,089.) A series of tests were conducted to evaluate the herbicidal effectiveness of the compounds of the invention as well as their degree of selectivity on established lawns.
Initial greenhouse tests were conducted to determine the activity of the compounds of the invention for the post-emergence control of lawn weeds. The results are summarized in Table I.

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R. J. Timmons et al 2-2-2 ; It is clear from Table I that the compounds '~ of the present invention possess a high order of activity , against both monocots and dicots at 5 to 10 pound per acre.
Additional tests were run at a lower application rate to determine whether the compounds give celective control of undesirable grass and weeds in the presence of Rentucky bluegrass. Table II records the results from several of the examples on bentgrass, pigweed, and bluegrass when applied by the same test method, but at one pound per acre.

10'78407 .' I
o-;,i ~ I o o ~ o o o o In o 'dP'~ ~ I
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O 1` ~ O -I N 1` co o~ o w l ~1 ~I r~l N N N

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R. J. Timmons et al 2-2-2 Table II demonstra~es the selectivity of the : herbicidal compounds of the invention. Compounds of examples 6, 8, 13, 14, 15 and 16 gave no post-emergence kill of either weeds or bluegrass at one pound per acre and thus are not included in Table II. The compounds of these examples require higher application rates.
Further tests were conducted to test the herbicidal effectiveness of m-heptafluoroisopropyl and m-chlorohexa-fluoroisopropyl, i.e., compounds outside the scope of Formula I. The three compounds tested were:
(1) 1,1-dimethyl-3-m-(1,1,1,2,3,3,3-heptafluoro-

2-propyl) phenylurea, (2) 1-methoxy-1-methyl-3-m-(1,1,1,2,3,3-hepta-fluoro-2-propyl) phenylurea and

(3) 1,1-dimethyl-3-m-(2-chloro-1,1,1,3,3,3-hexafluoro-2-propyl) phenylurea ; The results from the same initial greenhouse test of post-emergence weed control as reported in Table I for the examples of the present in~ention are shown in Table III for the hepta-fluoroisopropyl compounds (1) and (2) and the chloro-hexa-fluoroisopropyl case (3).

378~1~7 ~Q
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l~ol O O
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Q)~, P ~ U~

o .
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~L(378~07 .

R. J. Timmons et al 2-2-2 Comparison of the results in Table III with those of the active compounds in Tables I and II illustrate the striking loss of activity observed in compounds which are structurally similar to, but outside the scope of, Formula I
5 of the invantion.
Similarly, the pre-emergence herbicide activity of the compounds in Table III were examined. The results .. for annual bluegrass lPoa annua), barnyard grass (Echinochloa crus-galli), redroot pigweed (Amaranthus retroflexus), wheat-grass and Bermudagrass are shown in Table IV.

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-7846~7 R. J. Timmons et al 2-2-2 It is evident from the above that compounds containing the fully-halogenated isopropyl group also posses no signif-icant pre-emergence herbicide activity.
Activity of the m-isopropylphenylureas of the S in~ention in the greenhouse was confirmed in a variety of ~ield t~sts conducted with selected compounds. Post-emergence monocot control activity was determined by applying the chemicals as sprays to 1 foot by 2 foot plots of established grassy weeds. Tolerance to desirable grasses was measured by spray-ing the compounds on 1 foot by 2 foot plots of Windsor ~entucky bluograss. The resu ts are shown in Table V.

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8~07 ,, : R. J. Timmons et al 2-2-2 : Table V de~onstrates the ability o~ the compounds of this invention to selectively des~trQy undesirable grasses . such as bentgrass, Poa annua, and, i.n some cases, crabgrass ; in the presenca of desirable lawn species such as ~entucky Bluegrass.
Additional testing was conducted on larger, 2' ~. .
X 3' plots. The chemicals were formulated both on granular carricrs and ao sprays. Thc results are recordcd iA Table VI.

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R. J. Timmons et al 2-2-2 Similarly, two of the m-isopropyl phenylureas of the invention were tested for selective post-emergence ~icot control in the field. The chemicals were formulated both on granular carriers and as sprays. These formulations were applied to 2' X 3' plots of various dicot weed~ and also to bluegra~s sod to determine the turf tolerance of the formulations. The resul~s are shown in Table VII.

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~ 0 o ~q C~w lC~78407 ., R. J. Timmons et al 2-2-2 In the above field tests, the chemicals were applied to the plant foliage. That is, sprays were directed at and allowed to dry on the foliage. Granular materials were applied to previously moistened foliage to promote adherance.
S The following Tabel VIII shows the activity of the herbicides when applied to the soil rather than the foliage.
` In this case, the chemicals were applied as sprays or granular formulations and immediately "watered in", i.e. washe~ off the foliage onto the soil. In an initial test for soil activity, several of the m-isopropyl phenylureas were applied as sprays and then watered in to 1' X 2' plots of actively growing grassy and broadleaf weeds. A 1' X 2' strip of blue-grass sod was employed to measure turf tolerance. Table VIII lists the results.

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R. J. Timmons et al 2-2-2 ;: -33-'~ ' One of the more preferred compounds, l-methyl-3-m-(2-propyl) phenylurea (compound of example 20) was placed in an advanced test for activity against dicotyledonous weeds through the soil. It was applied as a granular ~ormula-tion and immediately watered in to 2' X 3' plots.

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~. J. Timmons et al 2-2-2 The data in Tables I through IX illustrate the versatility of the compounds of the present invention for weed control in lawns. Both greenhouse and field data illustrate the ability of these materials to control grassy and broadleaf weeds without harming desirable lawn grasses.
In addition, the compounds are active both as granular and spray formulations and may be applied either to the foliage or the soil. The latter properties are important when the compounds are applied commercially under a variety o field conditions. Moreover, Table III and IV demonstrate the herbicidal ln~ffectiveness of compounds outside the scope of ~ormula ~.

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Claims (20)

R. J. Timmons et al 2-2-2 WE CLAIM:

1. A compound of the structural formula in which R is from the group consisting of hydrogen, methyl, ethyl and methoxy; m and n are integers from 0 to 3; and X
is hydrogen when the sum (m+n) exceeds 4, otherwise X is from the group consisting of H, F and Cl.

2. The compound of Claim 1 in which X is hydrogen and m and n are each three.

3. The compound of Claim 1 in which X is fluorine and m and n are each two.

4. The compound of Claim 1 in which X is chlorine and m and n are each two.

5. The compound of Claim 1 in which X is fluorine, m is 0 and n is three.

6. The compound of Claim 1 in which X is hydrogen and m and n are each 0.

7. The compound of Claim 1 in which R is methyl.

8. 1, 1-Dimethyl-3-?-(1,1,1,3,3,3-hexafluoro-2-propyl) phenylurea.

R. J. Timmons et al 2-2-2

9. 1,1-Dimethyl-3-?-(1,1,2,3,3-pentafluoro-2-propyl)-phenylurea.

10. 1,1-Dimethyl-3-?-(2-chloro-1,1,3,3-tetrafluoro-2-propyl) phenylurea.

11. 1,1-Dimethyl-3-?-(1,1,1,2-tetrafluoro-2-propyl) phenylurea.

12. 1,1-Dimethyl-3-?-(2-propyl) phenylurea.

13. 1-Methyl-3-?-(2-propyl) phenylurea.

14. A process for the control of undesirable vegetation comprising applying to the vegetation a growth inhibiting amount of a compound of the formula in which R is from the group consisting of hydrogen, methyl, ethyl and methoxy; m and n are integers from 0 to 3; and X is hydrogen when the sum (m + n) exceeds 4, otherwise X is from the group consisting of H, F and Cl.

15. The process of Claim 14, in which the undesirable vegetation is monocotyledonous and dicotyledonous weeds.

16. The process of claim 14 in which the compound is applied to lawns for the selective post-emergent control of moncotyledonous weeds.

17. Process for the preparation of 1,1-dimethyl-3-(3-isopropyl-phenyl)-urea comprising reacting 3-isopropyl-phenylisocyanate with dimethylamine.

18. A process for the control of undesirable vege-tation comprising applying to the vegetation a growth inhibi-ting amount of 1,1-dimethyl-3-(3-isopropyl)-urea.

19. N-(3-isopropylphenyl)-N'-methoxy-N'-methylurea.

20. A process for the control of undesired vegetation comprising applying to the vegetation a growth inhibiting amount of N-(3-isopropylphenyl)-N'-methoxy-N'-methylurea.