CA1110081A - N-(benzenesulfonyl)thiocarbamates - herbicidal antidotes - Google Patents

Abstract

N-(BENZENESULFONYL) THIOCARBAMATES - HERBICIDAL ANTIDOTES

Abstract of the Disclosure N-(substituted and unsubstituted benzene-sulfonyl) thiocarbamates as new compositions of matter useful as active herbicidal antidotes to protect various crops from injury when used with a thiocarbamate herbicide; improved herbicidal compositions and utility of said compositions employing N-benzenesulfonyl thiocarbamates having the formula wherein X is hydrogen, methyl, chloro, bromo , or methoxy; n is an interger 1 to 3, inclusive; R1 is hydrogen or methyl; and R2 is alkyl having from 1 to 4 carbon atoms, inclusive, N-(p-chlorobenzenesulfonyl) carbamoyl-thiomethyl, benzyl or 4-chlorophenyl;
provided that when X is hydrogen and R1 is methyl, the R2 is other than ethyl.

Description

~110081 Background of the Invention ~ hile many herbicides are immediately toxic to a large number of weed pests, it is known that the effect of many herbi-c~des upon important plant cultivations is either non-selective or not adequately selective. Thus, many herbicides damage not only the weeds to be controlled but, to a greater or lesser extent, the desirable cultivated plants as well. This holds true for many herbicidal compounds which have been commercially suc-cessful and are commercially available. These herbicides include t~pes such as triazines, urea derivatives, halogenated acetani-lldes, carbamates, thiocarbamates and the like. Some examples of these compounds are described in U.S. Patents No. 2,913,327, 3,037,853, 3,175,897, 3,185,720, 3,198,786 and 3,582,314.
The side effect of in~ury to a cultivated crop by various herbicides i8 particularl~ inconvenient and unfortunate.
When used in the recommended amounts in the soil to control broadleaf weeds and grasses, serious malformstion or stunting of the crop plants sometimes result. This abnormal growth in the crop plants results in loss of crop y~eld. The search cont~nues for good selective herbicides.
Previous attempts are described to overcome th~s problem. The treatment of the crop ~eed with certain "hormonal"
antagoni~t~c agent3 prior to planting is described; see U.S.
Patents 3,131,5a9 and 3,564,768. ~he protect~e agents, as 11~0081 well as the herbicide in these prior processes are largely 8pecific to certain cultivated plant species or in the nature of the antagonistic agents. The prior antagonistic agents have not been notably successful. The aforementioned patents speci-fically exemplify and describe the treatment of seeds employing compounds of a different chemical class, not suggestive of the present invention.
The literature describes the preparation of certain N-(benzenesulfonyl) thiocarbamates for which no utility is dis-closed. The reference, Hirooka et al., NiPpon Ka~aku Zasshi:
1970, 91(3) 270(5), CA 73:14369w (1970), relates to the synthesis and reactions of bis-[N-(phe~ylsulfonyl)-formimidoyl]disulfides.
From certain;reactions of an appropriate disulfide with hydrogen peroxide, there is obtained N-(phenylsulfonyl)methyl thiolcarba-mates. ~urther, there i~ reference to certain alkyl p-toluene-~ulfonylthiocarbamates used in pharmacological e~aluat~ons.
These latter compounds are by Xriesel, D.C. et al., J. Pharm Sci., 968, 57(10), 1791-3.

Description of the Invention It h~s been discovered that cultivated crop plants ca~
be protected against injury by thiocarbamate-type herbicides, alonP or in mixtures or combination with other compounds. Further, as an a~ternative effect, the tolerance of growing plants, re particularly soybeans, to the ~locarbamate herbicides, re par-tlcularly S-n-propyl N,N-di-n-propylthiocarbamate, can be increased su~stantially by adding to the soil compound of the type N-(s~bstituted and unsubstituted benzenesulfonyl) thiocar-bæmate wh~ch is an effect~ve antidote w~th sa~d thiocarbamate herbicide, s ld compound corresponding to the following formula 11~Q08~

n ~ _ N _C ~R2 wherein X is hydrogen, methyl, chloro, bromo or methoxy; n is an interger from 1 to 3, inclusive, Rl is hydrogen or methyl;
and R2 is alkyl having from 1 to 4 carbon atoms, inclusive, methylthio-p-chlorobenzenesulfonyl carbamate, benzyl or 4-chlorophenyl; provided that when X is hydrogen and R~ iS
methyl, then R2 is other than ethyl.
As a preferred embodiment of the present invention, is a two part herbicide system comprising (1) a first part con~
sisting of at least one thiocarbamate herbicide and (2) a second part consisting of at least one compound having the formula X

n ~ ~ SR

wherein X iS hydrogen, methyl, chloro, bromo, or methoxy; n is an interger from 1 to 3 inclusive, Rl is hydrogen or methyl;
and R2 is alkyl having from 1 to 4 carbon atoms, inclusive, N-(p-chlorobenzenesulfonyl) carbamoyl-thiomethyl), benzyl or 4-chlorophenyl; provided that when X is hydrogen and Rl is methyl, then R2 is other than ethyl; said compound being anti-dotally active with said thiocarbamate herbicide.
Certain of the compounds disclosed herein are considered new compositions of matter and correspond to the following formula 111~Q8~
n ~3 wherein X is hydrogen, methyl, chloro, bromo or methoxy; n is an interger from 1 to 3, inclusive, Rl is hydrogen or methyl;
and R2 is alkyl having from 2 to 4 carbon atoms, inclusive, N-(p-chlorobenzenesulfonyl) carbamoly-thiomethyl, benzyl or 4-chlorophenyl; provided that when X is methyl, then R2 is other than alkyl and provided that when X is hydrogen and R
is methyl, then R2 is other than ethyl.
In the above descriptions,the following embodiment is intended for the various alkyl substituent groups. As exemplary of the alkyl portion wïthin the preferred embodiment are the following: Methyl, ethyl, n-propyl, isopropyl, n-butyl, sec.-butyl, isobutyl, and tert.-butyl. Whereas n can be an interger from 1 to 3, inclusive, preferably n is 3 when X is methyl; and n is a para-substitution of the X moiety.
As an alternative mode of action, the compounds of this invention may interfere with the normal herbicidal action of the thiocarbamate-type and other herbicides to render them selective in their action. Whichever mode of action is present the corresponding beneficial and desirable effect is the continued herbicidal effect of the thiocarbamate with the accompan~ing decreased herbicidal effect on desired crop species. This advantage and utility will become more appar~nt hereinafter.
Therefore, the terms "herbicide antidote" or "anti-dotal amount", is meant to describe that effect which tends to counteract the normal injurious herbicidal response that the herbicide might otherwise produce. Whether it is to be termed a remedy, interferant,protectant, or the like, will depend upon the exact mode of action. The mode of action is varied, but the effect, which is desirable, is the result of the method of treating the soil in which a crop is planted. Hitherto, there have been no systems which have been satisfactory for this purpose.
The compounds of this invention represented by the above formulas can be prepared by several different procedures depending upon the starting materials.
The appropriate intermediate, arylsulfon$mide, was reacted with an alkyl chlorothiolformate in the presence of a hydrogen chloride acceptor to prepare the desired com~ound.
Work-up and purification procedure3 involved standard methods of extraction, distillation or crystallization. In st instan-ces, character;ization of the structure was by infrared spectroscopy, nuclear magnetic resonance or mass spectroscopy, as well as physical constants.
The compounds of the present invention and their pre-paration are re particularly lllustrated by the following examples. Follo~Hngthe examples of preparation is a table of compounds wh ch are prepared according to the procedures des-cribed herein. Compou~ number~ have been assigned to them and are used for ~dentification throughout the balance of the specification.

E~XAMPIE
Preparatlon of N-(P-methoxvbe~zenesulfonYl~-ethYl thiolcarbamate.
p-Methoxy~enzenesulfonamide (11.7 g., 0.64 le), potas~ium carbon~te (21.5 g., 0.156 mole), and ethyl chlorothiol-formate (8.5 g., 0.068 mole) were refl~ed in 80 ml. of acetone for eight hours. The cooled mlxture was poured into 350 ml.
water snd the solution flltered through Celite and extracted with benzene to r~move any unreacted chlorothiolfonmate. It lllQQ81 was then acidified with hydrochloric acid ~pH about 2) with cool-ing. The mixture was extracted with benzene and the extract washed with water and dried over magnesium sulfate. Removal of the solvent left the product as a very viscous oil. There was obtained 8.4 g. (48~ theory) of the title compound, n30 1.5502.

EXAMPLE II
Preparation of N-~p-chlorobenzenesulfonyl~-eth~l thiolcarbamate.
p-Chlorobenzenesulfonamide (12.0 g., 0.063 mole), potassium carbonate (21,5 g., 0.156 mole), and ethyl chlorothiol-formate (8.5 g., 0.068 mole) were refluxed in 75 ml. of acetone for six hours. The work-up was as in Example I. The crude product was triturated with hexane and dried. There was obtained 12.4 g. (70% of theory) of the title compound, m.p. 93-95C. The structure was confirmed by infrared, nuclear magnetic resonasce, and mass spectroscopy.

EXAMP~E III
Preparation of N-(benzenesulfon~l)-ethvl th~olcarbamate.
8enzenesulfonamide (39.3 g., 0.25 le~, and potassium carbonate (90 g., 0.65 mole) were placed in 300 ml. of acetone and ethyl chlorothiolformate (41 g., 0.33 l~) added over several hours. The m~xture was s~irred one hour at room temperature, then refluxed 12 hours. It was cooled, poured into one 1. of water and acidified wit~ 100 ml. hydrochloric acid. The product was extracted with 250 ml. benzene and the extract dried over magnesium sulfate. It was f~ltered and the solvent removed.
Pentsne (100 ml.) was added, whereupon the product cry3tallized.
It wa~ filtered, washed wlth 50 ml. pentane, and dried at 50C.
There was obtained 58 g. (95~ of theory~ of the title com~ound, m.p. 100-103C. Analys~s: N, calculated, 5.72; found, 5.59;
Analys~s: S, ca~culatedj 26 ~ found, 2S.24.

111~081 EXAMPLE IV
Preparation of N-(p-chlorobenzenesulfonyl)-p-chlorophenyl thiol-carbamate.
-p-Chlorobenzenesulfonamide (19.1 g., 0.1 mole), potas-sium carbonate (30 g., 0.22 le), and p-chlorophenyl chloro-thiolformate (22 g , 0.11 mDle) in 150 ml. acetone were refluxed and stirred for 10.5 hours. The cooled mixture was poured into one l~ter water and acidified with acetic acid. The precipitate was filtered, washed with water and dried. There was obtained 20 g. (55.5% of theory) of the title compound, m.p. 129-132C.
Analysis: N, calculated, 3.85; found, 4.83 Analysis: S, calculated, 17.67; found, 17.37.
The ~olLowing is a table of the compounds which are prepared according to the aforementioned procedures. Compound numbers have been assigned to them and are used for identification throughout the balance of the specification.

TABLE I

~R2 1110(~81 m.p. c.
COMPOUND R R or 30 NUMBER n x 1 2 nD
1 1 para-CH3 H C2H5 104-110

2 1 H H C2H5 100-10~

3 1 para-Cl H 4-Cl-0 129-132

4 1 ~ara-Cl CH3 C2H5 1.5643 1 para-Cl H C2H5 g3-95 6 1 para-Br H C2H5 102-107 7 1 Para-Cl H n-C3H7 94-96 8 1 para-Cl H i C3~7 77-83 9 1 ~ -OCH3 H C2H5 1.5502 1 para-Cl H CH20 94-96 11 3 2,4,6-CH3 H C2H5 105-108 12 ~ Para-Cl ~ -CH2sc(O)~ (O2)-0-Cl(p) 238-239 dec.
The herbicide indicated in the tables and e~sewhere are used at rates which produce effective contr~l of undesirable vegetation. The range of rates employed herein produce represen-tative results within the recommended amounts set forth by the supplier. Therefore, the weed control in each instance is com-mercially acceptable within the desired or recommended am~unt.
It i~ clear that the class of herbicidal agents des-cribed and lllustrated herein is characterized as an effective herbicide exhibiting such activity. The degree of this herbi-cldal activity varies among specific compounds and among c~mbi-nat~ons of specif~c compou~ds within the class. Similsrly, the degree of activlty to some extent varies Emong the species of plants to which ~ spe~ific herbicidal compound or comb~nation may be applled. Thus, select~on of a specific herbicidal compound or c~mbination to control unde~irable plant species readily may be made. Within ~he present invention, the prevention of inJury to a de~ired crop specie~ in~e presenee of a spec~fic compo~nd or comb~natio~ m~y be achie~ed. The beneficial pLant species which _g_ can be protected by this method is not intended to be limited by the specific crops employed in the e2amples.
The herbicidal compounds employed in the utility of this invention are active herbicides of a general type. That is, the members of the classes are herbicidally effective against a wide range of plant species with no discr~mination between desirable and undesirable species. The method of controlling vegetation comprises applying an herbicidally effective amount of the herein described herbicidal compounds to the area or plant locus where control is desired. The compositions as set forth in this inven-tion include those wherein the preferred active thiocarbamate herbicidal compound is preferably S-n-propyl N,N-di-n-propyl thiocarbEmate., A~ herb~cide as used herein means a compound which con-trols or modifies the growth of vegetation or plants. Such con-trolling or difying efects include all deviations from natural development; for example, k~lling, retardat~on, defoliation, desic-cation, regulation, ~tunting, tillering, stimulation, dwarfing and the like. By "plants", it is meant germinant seed~, emerging seedlings and established vegetation including the roots and above-ground portions.

Eval~aCio~ ~r~cedores Flats to be used for growing the crops a~d weed spec~es were filled with loamy sand soil. Stock solutions of the herbi-oide ~nd e ch candidate antidote were prepared as foll~ws:
A. Herbicide - S-n-propyl N,N-di-n-propyl thiocarbamate - VERMAM ~ 6E - 1560 mg. of VERN~M 6E
was diluted in 250 ml. of water so that 5 ml. applied to a flat is equi~alent to 6 lb/A per flat (based) ~ 08 1 on the surface area of a flat).

B. Antidote - of each candidate 78 mg. was dissolved in 20 ml. of acetone with 1% Tween 20 (polyoxyethylene sorbitan nolaurate) so that

5 ml. when applied by pre-plant incorporation techni~ue (PPI) ~s equal to 5 lb/A per flat.

The herbicide and antidotes were applied to the soil together as a tank mix employing pre-plant incorporation tech-nique. To prepare the combined tank mix, 5 ml. of the VERNAM Q
stock solution and 5 ml. of each of the antidote stock solutions were admixed, followed by incorporation into the soil from the flats during incorporation in a rotary mixer.
One row each of the following weeds and crop was seeded into the treated soll in the flats:

Watergrass (Echinochloa crus~alli);
Foxtail (Sataria viridis), and Soybeans (GlYcine max) The ~lats were placed on greenhouse benches where temperatures were maintained between 70-90F. The soil was watered by sprinkling to Rssure good plant growth. Injury ratings were taken 2 and 4 weeks after the application was made. Indi-viâual flats treated with the herbicide alon~ were included to provide a basis for determining the æmount of injury reduction provided by the herbicide antidotes.
The following table includes results as percent protec-tion for the crop according to the procedures discussed above.
The percent protection is determined by a ~om~arison with flats not treated with the c~ndidate ant~dotes of this invention.

TABLE II

Application Method : Pre-plant Incorporation - PPI (Tank Mix) Crop Species : Soybeans (GlYcine max~
Weed Species : Foxtail (S~taria viridis) Watergras ~ crus~alli) * - % injury ** ~ % protection __________..______________________________________________________ PPI (6 1b/A~ (Tank Mix) CO~OUND
NUMBER SoYbeans Watergrass Foxtail VERNAM 6 lb/A 40* 100* 100*
_________________________________________________________________ 1** , 37.5 0 0 2 37.5 0 0

6 25 0 0

7 25 0 0

8 5~ 0 0

9 25 0 0 ~Qa 75 0 0 11 33 o o ~2 50 0 0 $ ~ Pre-plant incorporatlo~ of VERNAM~ and antidote applied ~epurately to soil prior fo i~corporation.

-1~-1~10~1 The thiocarbamate herbicide S-ethyl cyclohexylethyl thiocarbamate and compound number 6 when applied to the soil to-gether as a tank mix employing pre-plant incorporation technique, exhibited 50 percent protection to grain sorghum (milo) planted in the treated soil. That is, the injury to emerging grain sorg-hum plants was decreased by at least 50 percent when grown in soil treated with a tank mix of compound number 6 and S-ethyl cyclohexylethyl thiocarbamate. This is compared to grain sorghum (milo) planted in soil containing a treatment of only the thiocarbamate herbicide.
Various other varieties of legumes were tes~ed for antidote activity in conjunctlon with a representat~ve thiocarba-mate herbicide and a N-(benzenesulfonyl) thiocarbamate. Legumes are plants that have a symbiotic relationship with nitrogen fix-ing organisms. For example, soybeans, varieties of phaeolus vulgarius, peanuts, alfalfa, cloves, peas and the l~ke.
The antidote candidate from the above list of N-(ben-zenesulfonyl) thiocarbamates com~ound number 5 was used at the rates of 1 and 2 lb/A. The stock solution used consisted of 39 mg. dissolved in 25 ml. of acetone, such that 2.5 ml~ is equivalent to 1 lb/A when applied pre-plant incorporated. The representative thiocarb~mate herbicide was EPTC, S-ethyl N,N-dipropyl thiocarbamate. The herbicide stock solution was made up by dissolving 1560 mg. of EPTC 6E in 2~0 ml. water, ~uch that 5 ml. of solution was equivalent to 6 l~/A when pre-plant incorporated in the soil.
~ avy beans and pinto beans were evaluated ln this test.
Also pre~ent in the planted flats were the weed spec~es, water-grass and fox ail. The results were rated at two and four weeks after treatment and seeding. After two weeks EPTC at 6 lb/A with 1 lb/A and 2 lb/A compound number 5 present injured only ~0 percent of the navy beans and 0 percent of the pinto bean plants.
After four weeks at 1 lb/A navy bean plants were protected 23 percent and pinto bean plants were protected 40 percent. At 2 lb/A after four weeks navy beans were protected 23 percent and pinto beans 20 percent. The watergrass and foxtail weed species were completely (100 percent) controlled four weeks after treatment with the antidote and herbicide.

Seed Treatment Test Small flats were filled with Felton loamy sand soil.
Soil incorporated herbicides were applied at this time. The soil from each flat was placed into a five-gallon cement mixer where the soil was mixed as the herbicides were applied using a pre-determined amount of a stock solution containing 780 mg. of approximately 75 percent active ingredient to 125 ml. of water.
Five ml. of stock solution was applied to the ssll in a volu-metric pipet. Five ml. of stock solution contained an equiYalent of herbicide which equals to ~ix pounds per acre when applied to the soil in the flats. After the herbicide incorporation, the soil was placed back into the flats.
Flats of herbicide-treated and untreated soil were then ready to be planted. A pint sEmple of soil was removed from each flat and placed next to each flat for later use ~n covering up the seeds. The soil was leveled and rows one-half inch deep were made for planting seeds. Alternating rows of treated and un-treated crop seeds were sown. In each test, soybean (G1YC~ne max) seeds ~ere planted in each row. Rows were approximately one ~nd one-half inches apart in the flat. Seed~ were treated by preparing a stock solution by dissolving 2$0 mg. of the anti-dote compound in 2.5 ml. of acetone, then using 0.5 ml. of the 1 llQ~8 1 stock solution to treat 10 g. of soybean seed equivalent to 0.5 percent w/w. Antidote compounds can also be applied as liquid slurries and powders or dusts. In some cases, acetone is used to dissolve powdered or solid compounds so they could be more effectively applied to the seeds.
After the flats were seeded, they were covered with the one pint of soil which had been removed just prior to planting.
Flats were placed on greenhouse benches were temperatures ranged from 70-90F. Flats were watered by sprinkling as needed to assure good plant growth. Percent control ratings were taken four weeks after the treatments were applied.
In each test, the herbicide was applied alone, in com-bination with t,he seed protec~ant, and the seed protectant was applied alone to check for phytotoxoclty. The untreated ad;acent row was employed to observe any beneficial lateral movement of the antidote compound through the soil. The degree of the effect was noted by compari~on with the ccntrol.
In this seed treatment test with the herbicide S-n-propyl N,N-di-n-propyl thiocarbamate, compound number 5 exhib~ted 50 per-cent protection to the treated soybean seeds. That is, the inj~ry was reduced by at least 50 percent to the emerging soybea~ plants grown rom seed treated with compound number 5 compared to un-treated seed grown in soll containing the thiocarbamate herbicide.
The compounds and compositions of this invention were employed in effective herbicidal compositions com~rising the anti^
dote and a representative thiocarbamate herbicide as descrlbed hereinabove. The herbicidal composit~ons were tested in the foll~wing m~nner The ~ompositions of the present invention for the pro-tection of culti~ated crop pLants comprlse an act$ve herbicidal compound and an antido~e therefor ~elec~ed from the above-described com~ounds. The compositlons of herb~cide and ant~doee can be 111()081 prepared by conventional methods through the thorough mixing and grinding of the active herbicide agents and the antidote with su~table carriers and/or other distribution media, possibly ~ith the addition of dispersion agents or solvents.
The antidote compounds and compositions of the present invention can be used in any convenient form. Thus, the antidote com~ounds can be formulated into emNlsifiable liquids, emulsifiable concentrates, liquid, wettable powder, powders, granular or any other convenient form. In its preferred form, a non-phytotoxic quantity of an herbicidal antidote compound is admixed with a selected herbicide and incorporated into the soil prior to or after planting the seed It is to be understood, however, that the herbicides can be incorporated into the soil and thereafter the antidote compound can be incorporated into the 80il. Moreover, the crop seed itself can be treated with a non-phytotoxic quRntity of the compound and planted into the soil which has been treated with herbicides, or untreated with the herbicide and su~sequently treated with the herbicide. The addition of the antidote com-pound does not affect the herbicidal acti~ity of the herbicides The amount of antidote compound present can range bet-ween about 0.001 to about 30 parts by weight of antidote compound described herein per each part by weight of herbicide. The exact ~mount of antidote compound will usually be determined on economic ratios for ehe most effective ~mount usable. It is understood tkat a non-phytGtoxic quantity of antidote compound will be employed in the herbicidal com~ositions described herein.

Claims (24)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A herbicidal composition comprising a thiocarbamate herbicide and an antidotally effective amount of a compound corresponding to the formula in which X is hydrogen, methyl, chloro, bromo, or methoxy;
n is an interger of 1 to 3; R1 is hydrogen or methyl; and R2 is alkyl having from 1 to 4 carbon atoms, inclusive, N-(p-chlorobenzene sulfonyl) carbamoyl-thiomethyl benzyl or 4-chlorophenyl; provided that when X is methyl, then R2 is other than alkyl and when X is hydrogen and R1 is methyl, then R2 is other than ethyl; said compound being antidotally active with said thiocarbamate herbicide.

2. The herbicidal composition according to Claim 1 in which X is para-methyl, R1 is hydrogen and R2 is alkyl.

3. The herbicidal composition according to Claim 2 in which R2 is ethyl.

4. The herbicidal composition according to Claim 1 in which X is hydrogen, R1 is hydrogen and R2 is alkyl.

5. The herbicidal composition according to Claim 4 in which R2 is ethyl.

6. The herbicidal composition according to Claim 1 in which X is para-chloro, R1 is hydrogen and R2 is alkyl.

7. The herbicidal composition according to Claim 6 in which R2 is ethyl.

8. The herbicidal composition according to Claim 6 in which R2 is isopropyl.

9. The herbicidal composition according to Claim 1 in which X is para-chloro, R1 is hydrogen and R2 is benzyl.

10. The herbicidal composition according to Claim 1 in which X is para-bromo, R1 is hydrogen and R2 is alkyl.

11. The herbicidal composition according to Claim 10 in which R2 is ethyl.

12. The method of protecting soybean crops from injury, said injury due to the thiocarbamate herbicide S-n-propyl di-n-propylthiocarbamate, comprising application to the soil in which said crop is to be planted and grown, a non-phytotoxic antidotally effective amount of a compound corresponding to the formula in which X is hydrogen, methyl, chloro, bromo, or methoxy, n is an interger of 1 to 3; R1 is hydrogen or methyl; and R2 is alkyl having from 1 to 4 carbon atoms, inclusive, N-(p-chlorobenzene sulfonyl) carbamoyl-thiomethyl, benzyl or 4-chlorophenyl; provided that when X is methyl, then R2 is other than alkyl and when X is hydrogen and R1 is methyl, then R2 is other than ethyl.

13. The method according to Claim 12 in which X is methyl, R1 is hydrogen and R2 is alkyl.

14. The method according to Claim 13 in which R2 is ethyl.

15. The method according to Claim 12 in which X is hydrogen, R1 is hydrogen and R2 is alkyl.

16. The method according to Claim 15 in which R2 is ethyl.

17. The method according to Claim 12 in which X is para-chloro, R1 is hydrogen and R2 is alkyl.

18 The method according to Claim 17 in which R2 is ethyl.

19. The method according to Claim 17 in which R2 is isopropyl.

20. The method according to Claim 12 in which X is para-chloro, R1 is hydrogen and R2 is benzyl.

21. The method according to Claim 12 in which X is para-bromo, R1 is hydrogen and R2 is alkyl.

22. The method according to Claim 21 in which R2 is ethyl.

23. The herbicidal composition as set forth in Claim 1 wherein said thiocarbamate herbicide is selected from the group S-n-propyl N,N-di-n-propyl thiocarbamate, S-ethyl di-propyl thiocarbamate, and S-ethyl cyclohexylethyl thiocarbamate.

24. The method of protecting a crop from injury, said injury due to a thiocarbamate herbicide selected from the group S-n-propyl N,N-di-n-propyl thiocarbamate, S-ethyl dipropyl thiocarbamate, and S-ethyl dipropyl thiocarbamate and S-ethyl cyclohexylethyl thiocarbamate; comprising application to the soil in which an herbicidally effective amount of said thiocarbamate is used, a non-phytotoxic amount of a compound corresponding to the formula in which X is hydrogen, methyl, chloro, bromo, or methoxy;
n is an interger of 1 to 3; R1 is hydrogen or methyl; and R2 is alkyl having from 1 to 4 carbon atoms; inclusive, N-(p-chlorobenzene sulfonyl) carbamoyl-thiomethyl), benzyl or 4-chlorophenyl; provided that when X is methyl, then R2 is other than alkyl, and when X is hydrogen and R1 is methyl, then R2 is other than ethyl; said compound being antidotally active with said thiocarbamate herbicide.