The compounds are of the class of N-[(substituted pyrimidin-2-yl)aminocarbonyl]-2-(sulfonylmethyl)benzenesulfonamides, useful as preemergent or postemergent herbicides or plant growth regulants.

BACKGROUND OF THE INVENTION 
.alpha.,2-Toluenedisulfonamide derivatives are useful as agricultural 
chemicals and in particular as herbicides. 
French Pat. No. 1,468,747 discloses the following para-substituted 
phenylsulfonamides, useful as antidiabetic agents: 
##STR1## 
where R=H, halogen, CF.sub.3 or alkyl. 
Logemann et al., Chem. Ab., 53, 18052 g (1959), disclose a number of 
sulfonamides, including uracil derivatives and those having the formula: 
##STR2## 
wherein R is butyl, phenyl or 
##STR3## 
and R.sub.1 is hydrogen or methyl. When tested for hypoglycemic effect in 
rats (oral doses of 25 mg/100 g), the compounds in which R is butyl or 
phenyl were most potent. The others were of low potency or inactive. 
Wojciechowski, J. Acta. Polon. Pharm. 19, P. 121-5 (1962) [Chem. Ab., 59 
1633 e] describes the synthesis of 
N-[(2,6-dimethoxypyrimidin-4yl)aminocarbonyl]-4-methylbenzenesulfonamide: 
##STR4## 
Based upon similarity to a known compound, the author predicted 
hypoglycemic activity for the foregoing compound. 
Netherlands Pat. No. 121,788, published Sept. 15, 1966, teaches the 
preparation of compounds of Formula (i), and their use as general or 
selective herbicides: 
##STR5## 
wherein 
R.sub.1 and R.sub.2 may independently be alkyl of 1-4 carbon atoms; and 
R.sub.3 and R.sub.4 may independently be hydrogen, chlorine or alkyl of 1-4 
carbon atoms. 
Compounds of Formula (ii), and their use as antidiabetic agents, are 
reported in J. Drug. Res. 6, 123 (1974): 
##STR6## 
wherein R is pyridyl. 
The presence of undesired vegetation causes substantial damage to useful 
crops, especially agricultural products that satisfy man's basic food 
needs, such as soybeans, wheat and the like. The current population 
explosion and concomitant world food shortage demand improvements in the 
efficiency of producing these crops. Prevention or minimizing the loss of 
a portion of such valuable crops by killing, or inhibiting the growth of 
undesired vegetation is one way of improving this efficiency. 
A wide variety of materials useful for killing, or inhibiting (controlling) 
the growth of undesired vegetation is available; such materials are 
commonly referred to as herbicides. The need exists, however, for still 
more effective herbicides that destroy or retard weeds without causing 
significant damage to useful crops. 
SUMMARY OF THE INVENTION 
This invention relates to novel compounds of Formula I and their 
agriculturally suitable salts, suitable agricultural compositions 
containing them and their method of use as general herbicides. 
##STR7## 
wherein 
L is SO.sub.2 NR.sub.3 R.sub.4 ; 
R is H, F, Cl, Br, NO.sub.2, CF.sub.3, C.sub.1 -C.sub.3 alkyl or C.sub.1 
-C.sub.3 alkoxy; 
R.sub.1 is H or C.sub.1 -C.sub.4 alkyl; 
R.sub.2 is H or CH.sub.3 ; 
R.sub.3 is C.sub.1 -C.sub.4 alkyl or OCH.sub.3 ; 
R.sub.4 is C.sub.1 -C.sub.4 alkyl; 
R.sub.8 is H, CH.sub.3 or OCH.sub.3 ; 
A is 
##STR8## 
W is O or S; 
X is H, Cl, Br, CH.sub.3, CH.sub.2 CH.sub.3, C.sub.1 -C.sub.3 alkoxy, 
CF.sub.3, SCH.sub.3 or CH.sub.2 OCH.sub.3 ; 
Y is CH.sub.3 or OCH.sub.3 ; 
Z is N, CH, CCl, CBr, CCN, CCH.sub.3, CCH.sub.2 CH.sub.3, CCH.sub.2 
CH.sub.2 Cl or CCH.sub.2 CH.dbd.CH.sub.2 ; 
Y.sup.1 is H, CH.sub.3, OCH.sub.3 or OCH.sub.2 CH.sub.3 ; and 
Q is O or CH.sub.2 ; 
and their agriculturally suitable salts; provided that: 
(1) when R.sub.3 is OCH.sub.3, then R.sub.4 is CH.sub.3 ; 
(2) the total number of carbon atoms of R.sub.3 and R.sub.4 is five or 
less; and 
(3) when W is S, then R.sub.8 is H. Preferred in increasing order for their 
higher activity and/or more favorable ease of synthesis. 
(1) Compounds of the generic scope wherein Z is N, CH, CCl, CBr or 
CCH.sub.3, W is O, and R.sub.8 is H or CH.sub.3 ; 
(2) Compounds of Preferred (1) wherein Z is CH or N, X is CH.sub.3 or 
OCH.sub.3, and R.sub.1 and R.sub.2 are H; 
(3) Compounds of Preferred (2) wherein A is 
##STR9## 
and R and R.sub.8 are H; 
(4) Compounds of Preferred (3) wherein R.sub.3 is C.sub.1 -C.sub.3 alkyl or 
OCH.sub.3, and R.sub.4 is CH.sub.3 ; and 
(5) Compounds of Preferred (4) wherein R.sub.3 is OCH.sub.3 or CH.sub.3. 
Specifically Preferred for highest activity and/or most favorable ease of 
synthesis are: 
2-[(Dimethylamino)sulfonylmethyl]-N-[(4,6-dimethylpyrimidin-2-yl)aminocarbo 
nyl]benzenesulfonamide, m.p. 203.degree.-204.degree. C.; 
2-[(Dimethylamino)sulfonylmethyl]-N-[(4,6-dimethoxypyrimidin-2-yl)aminocarb 
onyl]benzenesulfonamide, m.p. 171.degree.-176.degree. C.; 
2-[(Dimethylamino)sulfonylmethyl]-N-[(4-methoxy-6-methylpyrimidin-2-yl)amin 
ocarbonyl]benzenesulfonamide, m.p. 181.degree.-183.degree. C.; 
2-[(Dimethylamino)sulfonylmethyl]-N-[(4,6-dimethyl-1,3,5-triazin-2-yl)amino 
carbonyl]benzenesulfonamide, m.p. 209.degree.-210.degree. C.; 
2-[(Dimethylamino)sulfonylmethyl]-N-[(4,6-dimethoxy-1,3,5-triazin-2-yl)amin 
ocarbonyl]benzenesulfonamide, m.p. 200.degree.-203.degree. C.; and 
2-[(Dimethylamino)sulfonylmethyl]-N-[(4-methoxy-6-methyl-1,3,5-triazin-2-yl 
)aminocarbonyl]benzenesulfonamide, m.p. 200.degree.-205.degree. C. 
This invention also relates to novel compounds of Formula II which are 
useful intermediates for the preparation of the herbicidal compounds of 
Formula I. 
##STR10## 
wherein 
L, R, R.sub.1, and R.sub.2 are as previously defined, and 
Z is CH or N. 
This invention also relates to novel compounds of Formula III which are 
useful intermediates for the preparation of the compounds of Formula I. 
##STR11## 
wherein L, R, R.sub.1 and R.sub.2 are as previously defined. 
DETAILED DESCRIPTION 
Synthesis 
The compounds of Formula I, in which W=O, may be prepared as shown in 
Equation 1 by the reaction of an appropriately substituted benzenesulfonyl 
isocyanate with an appropriate aminopyrimidine or aminotriazine. 
##STR12## 
wherein 
R is H, F, Cl, Br, NO.sub.2, CF.sub.3, C.sub.1 -C.sub.3 alkoxy or C.sub.1 
-C.sub.3 alkyl; 
R.sub.1 is H or C.sub.1 -C.sub.4 alkyl; 
R.sub.2 is H or CH.sub.3 ; 
R.sub.4 is C.sub.1 -C.sub.4 alkyl; 
R.sub.3 is CH.sub.3 O or C.sub.1 -C.sub.4 alkyl; provided that when R.sub.3 
is CH.sub.3 O, then R.sub.4 is CH.sub.3, and provided that the total 
number of carbon atoms of R.sub.3 and R.sub.4 is five or less; 
A is 
##STR13## 
X is H, Cl, Br, CH.sub.3, CH.sub.3 CH.sub.2, C.sub.1 -C.sub.3 alkoxy, 
CF.sub.3, CH.sub.3 S or CH.sub.3 OCH.sub.2 ; 
Y is CH.sub.3, CH.sub.3 O or Cl; 
Z is N, CH, C-Cl, C-Br, C-CN, C-CH.sub.3, C--CH.sub.2 CH.sub.3, C-CH.sub.2 
CH.sub.2 Cl or C--CH.sub.2 CH.dbd.CH.sub.2 ; 
Y.sup.1 is H, CH.sub.3, CH.sub.3 O or OCH.sub.2 CH.sub.3 ; 
and 
Q is O or CH.sub.2. 
The reaction of Equation 1 is best carried out in an inert aprotic solvent 
such as methylene chloride, tetrahydrofuran or acetonitrile at a 
temperature between 20.degree. and 80.degree.. A catalytic amount of 
1,4-diazabicyclo[2,2,2]octane (DABCO) may be used to accelerate the 
reaction. In cases in which the products are insoluble in the reaction 
solvent, they may be isolated by simple filtration. When the products are 
soluble, they may be isolated by evaporation of the solvent and 
trituration of the residue with solvents such as 1-chlorobutane, 
ethylether or methanol and filtration. 
The benzenesulfonyl isocyanates of Formula III may be prepared as shown 
below in Equation 2, by phosgenation of the sulfonamides of Formula IV in 
the presence of butyl isocyanate. The sulfonyl isocyanates of Formula III 
may also be prepared, as shown in Equation 3, by phosgenation of the butyl 
ureas of Formula V. 
##STR14## 
wherein R, R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are as previously 
described. 
The above reaction is carried out by heating a mixture of the appropriate 
sulfonamide (IV), an alkyl isocyanate such as butyl isocyanate and a 
catalytic amount of a tertiary amine such as 1,4-diaza[2,2,2]bicyclooctane 
(DABCO) in xylene, or other inert solvent of boiling point 
.gtoreq.135.degree. to approximately 135.degree.. Phosgene is then added 
to the mixture over a 1-6 hour period until an excess of phosgene is 
present as indicated by a drop in the boiling point to less than 
130.degree.. The mixture is cooled and filtered to remove a small amount 
of insoluble by-products. The solvent and the alkyl isocyanate are 
distilled off in-vacuo leaving a residue of the crude, sulfonyl 
isocyanate, III, which can be used without further purification. 
##STR15## 
wherein R, R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are as previously 
described. 
The compounds of Formula V are conveniently prepared by stirring a mixture 
of the sulfonamides, IV, anhydrous potassium carbonate, and n-butyl 
isocyanate in acetone or methyl ethyl ketone at 25.degree.-80.degree. 
until all of the isocyanate has reacted. The products are isolated by 
quenching in dilute mineral acid and recrystallizing the solid product. 
The compounds V are treated with phosgene and a catalytic amount of DABCO 
in refluxing xylene or chlorobenzene in a manner analogous to that 
described in Equation 2. 
The sulfonyl isocyanates of Formula III may also be prepared as shown in 
Equation 4, by the method of Ulrich et al. [J. Org. Chem. 34, 3200 
(1969)]. 
##STR16## 
The synthesis of heterocyclic amine derivatives such as those depicted by 
Formula VIII has been reviewed in "The Chemistry of Heterocyclic 
Compounds", a series published by Interscience Publ., New York and London. 
Aminopyrimidines are described by D. J. Brown in "The Pyrimidines", Vol. 
XVI of the above series. 
The synthesis of the bicyclic pyrimidines of Formula VIII is described in 
the following references: 
Braker, Sheehan, Spitzmiller and Lott, J. Am. Chem. Soc. 69, 3072 (1947). 
Mitter and Bhattacharya, Quart. J. Indian. Chem. Soc. 4, 152 (1927). 
Shrage and Hitchings, J. Org. Chem. 16, 1153 (1951). 
Caldwell, Kornfeld and Donnell, J. Am. Chem. Soc. 63, 2188 (1941). 
Fissekis, Myles and Brown, J. Org. Chem. 29, 2670 (1964). 
All of the above are herein incorporated by reference. 
Compounds of Formula I, in which W=O, can also be prepared by the method 
described in Equation 5. 
##STR17## 
wherein 
R, R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are as described previously; 
R.sub.12 is methyl; 
R.sub.13 is C.sub.1 -C.sub.3 alkyl; 
X.sub.2 is Cl or Br; 
Y.sub.2 is H, Cl, Br, methyl, ethyl or CF.sub.3 ; 
Y.sub.3 is Cl or Br; 
Y.sub.4 is methyl, ethyl or CF.sub.3 ; and 
E is CH.sub.3 S--. 
REACTION STEP (5a) 
In Reaction Step (5a), an aromatic sulfonamide of Formula IV is contacted 
with a heterocyclic isocyanate of Formula VII to yield an 
N-(haloheterocyclicaminocarbonyl) aromatic sulfonamide of Formula II. 
The heterocyclic isocyanates used in Reaction (5a) may be prepared 
according to methods described in Swiss Pat. No. 579,062, U.S. Pat. No. 
3,919,228, U.S. Pat. No. 3,732,223 and Angew Chem. Int. Ed. 10, 402 
(1976), the disclosures of which are herein incorporated by reference. 
The aromatic sulfonamide and the heterocyclic isocyanate are contacted in 
the presence of an inert organic solvent, for example, acetonitrile, 
tetrahydrofuran (THF), toluene, acetone or butanone. Optionally, a 
catalytic amount of a base, such as 1,4-diazabicyclo[2.2.2]octane (DABCO), 
potassium carbonate, sodium hydride or potassium tert-butoxide, may be 
added to the reaction mixture. The quantity of base constituting a 
catalytic amount would be obvious to one skilled in the art. The reaction 
mixture is preferably maintained at a temperature of about 25.degree. to 
110.degree. C., and the product can generally be recovered by cooling and 
filtering the reaction mixture. For reasons of efficiency and economy, the 
preferred solvents are acetonitrile and THF, and the preferred temperature 
range is about 60.degree. to 85.degree. C. 
REACTION STEPS (5b) AND (5c) 
In Reaction Steps (5b) and (5c), one or two of the halogen atoms on the 
heterocyclic ring of the compound of Formula II is displaced by a 
nucleophilic species. Generally, this may be done by contacting the 
compound of Formula II either with alkanol, R.sub.12 OH, or with alkoxide, 
--OR.sub.12, where R.sub.12 is as defined above. 
Thus, in Reaction Step (5b), a compound of Formula II, substituted with one 
displaceable group, can be contacted with at least one equivalent of 
alkanol, R.sub.12 OH. This reaction is sluggish, however, and it is 
preferred to contact the compound of Formula II with at least two 
equivalents of alkoxide, --OR.sub.12. The alkoxide can be provided in a 
number of ways: 
(a) The compound of Formula II can be suspended or dissolved in an alkanol 
solvent, R.sub.12 OH, in the presence of at least two equivalents of 
alkoxide, --OR.sub.12. The alkoxide can be added directly as alkali metal 
or alkaline earth metal alkoxide or can be generated by the addition to 
the alkanol solvent of at least two equivalents of a base capable of 
generating alkoxide from the solvent. Suitable bases include, but are not 
limited to, the alkali and alkaline earth metals, their hydrides and 
tert-butoxides. For example, when R.sub.12 is methyl, the compound of 
Formula II could be suspended or dissolved in methanol in the presence of 
two equivalents of sodium methoxide. Alternatively, two equivalents of 
sodium hydride could be used in place of the sodium methoxide. 
(b) The compound of Formula II can be suspended or dissolved in an inert 
solvent in the presence of at least two equivalents of alkoxide, 
--OR.sub.12. Suitable inert solvents include, but are not limited to, 
acetonitrile, THF and dimethylformamide. The alkoxide may be added 
directly as alkali metal or alkaline earth metal alkoxide or may be 
generated from alkanol and a base as described in (a) above. For example, 
when R.sub.12 is methyl, the compound of Formula II could be suspended or 
dissolved in THF in the presence of two equivalents of sodium methoxide. 
Alternatively, two equivalents each of methanol and sodium hydride could 
be used instead of sodium methoxide. 
For reasons of economy and efficiency, procedure (a) is the more preferred 
method. 
It should be noted that two equivalents of alkoxide are required for 
Reaction Step (5a) whereas only one equivalent of alkanol is needed for 
the same process. This difference is due to the reaction which is believed 
to occur between the alkoxide and the sulfonyl nitrogen of the sulfonamide 
of Formula VIII. When alkoxide is used, the first equivalent of alkoxide 
removes a proton from the sulfonyl nitrogen, and it is only the second 
equivalent which effects displacement of the halogen. As a result, two 
equivalents of alkoxide are required. The resulting salt must be 
acidified, e.g., with sulfuric, hydrochloric or acetic acid, to yield a 
compound of Formula IX. Applicant, of course, does not intend to be bound 
by the mechanism described above. 
In Reaction step (5c) a compound of Formula IXa, substituted with at least 
one displacement group, is contacted with either one equivalent of 
alkanol, R.sub.13 OH, or with two equivalents of alkoxide, --OR.sub.13 
where R.sub.13 is as described above. The compound of Formula IXa is 
prepared according to Reaction Step (5b) from a compound of Formula IX 
where Y.sub.2 is Cl or Br. When alkoxide, --OR.sub.13 is used, it may be 
provided in either of the methods described above in connection with 
Reaction Step (5c), and the resulting salt can be acidified to yield a 
compound of Formula X. 
When R.sub.12 =R.sub.13, Reaction Steps (5b) and (5c) may be combined. 
Thus, a compound of Formula II may be contacted either with at least two 
equivalents of alkanol, R.sub.13 OH, or with at least three equivalents of 
alkoxide, --OR.sub.13. 
When a compound of Formula II contains two displaceable groups, i.e., both 
X.sub.2 and Y.sub.2 are Cl or Br, certain reaction conditions will favor 
displacement of only one of the group. These conditions are the use of low 
temperatures and, when alkoxide is used, the slow addition of the 
stoichiometric amount of alkoxide or alkoxide-generating base to the 
medium containing the compound of Formula II. 
When alkoxide is used, both Reaction Steps (5b) and (5c) are preferably run 
at temperatures within the range of about -10.degree. to 80.degree. C., 
the range of about 0.degree. to 25.degree. C. being more preferred. 
Reaction Steps (5b) and (5c) are more sluggish when alkanol is used 
instead of alkoxide, and more drastic conditions are required for the 
reaction to go to completion. Thus, higher temperatures, up to and 
including the boiling point of the alkanol itself, are required. 
REACTION STEP (5d) 
Reaction Step (5d) involves the displacement of the halogen atom in a 
compound of Formula IIa by a methylthio nucleophile. The starting 
material, a compound of Formula IIa, is prepared according to Reaction 
Step (5a), and Y.sub.4 is limited to C.sub.1 -C.sub.2 alkyl and CF.sub.3. 
For this reaction, the compound of Formula IIa is suspended or dissolved in 
an inert solvent, such as acetonitrile or THF. At least one equivalent of 
the nucleophilic species and at least two equivalents of a base are then 
contacted with the starting material. The first equivalent of base is 
believed to neutralize the sulfonamido proton. The second equivalent of 
base generates mercaptide ion from the mercaptan. Suitable bases include 
sodium hydride, sodium methoxide and sodium hydroxide. 
Suitable reaction temperatures are within the range of about -10.degree. to 
80.degree. C., with a range of about 0.degree. to 25.degree. C. being 
preferred. The product may be isolated by dilution of the reaction mixture 
with water, mild acidification and filtration. 
The sulfonamides of Formula IV can be prepared by the four step reaction 
sequence shown in Equation 6. 
##STR18## 
wherein R, R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are as defined in 
Equations 1-5, with the exception that R cannot be NO.sub.2. 
In step 6a, the o-nitrobenzylsulfonyl chlorides of Formula XII, which are 
well-known in the art, are treated with an amine of Formula XIIa in an 
inert organic solvent such as methylene chloride, ethyl ether or 
tetrahydrofuran at 0.degree.-50.degree.. The amine may be taken in excess 
to act as an acid acceptor; or, alternatively, a tertiary amine such as 
triethylamine or pyridine may be used as an acid acceptor. The by-product 
amine hydrochloride is filtered off or washed out of the solvent with 
water and the product isolated by evaporation of the solvent. 
The reduction described in step 6b is accomplished by treating a solution 
of the compounds of Formula XIII in a solvent such as ethanol, ethyl 
acetate, or diglyme, in a pressure vessel, with 50-1000 pounds per square 
inch of hydrogen at 25.degree.-150.degree. in the presence of a 
hydrogenation catalyst such as 5-10% palladium absorbed on carbon. When 
the theoretical amount of hydrogen has been absorbed, the solution is 
cooled and the catalyst is removed by filtration. The product is then 
isolated by evaporation of the solvent. 
In the case where R=NO.sub.2, the reduction of step 6b an be accomplished 
using ammonium sulfide or sodium hydrosulfide instead of catalytic 
hydrogenation. This type of procedure is described in Organic Synthesis 
Coll. Vol. III, pgs. 242-3, John Wiley and Sons, Inc., New York and London 
(1955), the disclosure of which is herein incorporated by reference. 
The diazotization and coupling with sulfur dioxide, described in step 6c, 
is accomplished in the following manner. A solution of the aniline of 
Formula XIV in a mixture of concentrated hydrochloric acid and glacial 
acetic acid is treated with a solution of sodium nitrite in water at 
-5.degree. to 0.degree.. After stirring for 10-15 minutes at 0.degree. to 
insure complete diazotization, this solution is added to a mixture of an 
excess of sulfur dioxide, and a catalytic amount of cuprous chloride in 
glacial acetic acid at 0.degree.-5.degree.. The temperature is kept at 
0.degree.-5.degree. for 1/4 to 1 hour then raised to 20.degree.-25.degree. 
and held at that temperature for 2-4 hours. This solution is then poured 
into a large excess of ice water. The sulfonyl chloride products, XV, can 
be isolated by filtration or by extraction into a solvent such as ethyl 
ether or methylene chloride followed by evaporation of the solvent. 
The amination described in step 6d is conveniently carried out by treating 
a solution of the sulfonyl chloride of Formula XV with an excess of 
anhydrous ammonis in a solvent such as ethyl ether or methylene chloride 
at 0.degree.-25.degree.. If the product sulfonamide, IV, is insoluble it 
may be isolated by filtration followed by washing out the salts with 
water. If the product sulfonamide is soluble in the reaction solution, it 
may be isolated by filtering off the precipitated ammonium chloride and 
evaporation of the solvent. 
Compounds of Formula I, in which W=O and R.sub.8 =H, can also be prepared 
by the reaction of an appropriately substituted sulfonamide, IV, with the 
methyl carbamate of the appropriate aminoheterocycle, XVI, in the presence 
of an equivalent of trimethylaluminum as shown in Equation 7. 
##STR19## 
wherein R, R.sub.1, R.sub.2, R.sub.3, R.sub.4 and A are as previously 
defined. 
The reaction of Equation 7 is best carried out in an inert solvent such as 
methylene chloride at 10.degree.-45.degree. and ambient pressure. The 
preferred mode of addition is to add the trimethylaluminum to a solution 
or slurry of the sulfonamide, IV, a mildly exothermic reaction occurs 
accompanied by the evolution of gas. The addition of the heterocyclic 
carbamate, XVI, is then made and the mixture is stirred at ambient to 
reflux temperatures for 6 to 48 hours. The addition of aqueous acid such 
as dilute hydrochloric or acetic acid removes inorganic salts from the 
product contained in the organic phase. Evaporation of the methylene 
chloride yields the crude product which can be purified by 
recrystallization or column chromatography. 
As shown in Equation 8, compounds of Formula I, in which W is sulfur and R, 
R.sub.1, R.sub.2, R.sub.3, R.sub.4 and A are as previously defined and 
R.sub.8 is H are prepared by reaction of an appropriately substituted 
sulfonamide, IV, with a heterocyclic isothiocyanate of Formula XVII. 
##STR20## 
The reaction of Equation 8 is best carried out by dissolving or suspending 
the sulfonamide and isothiocyanate in a polar solvent such as acetone, 
acetonitrile, ethyl acetate or methyl ethyl ketone, adding an equivalent 
of a base such as potassium carbonate and stirring the mixture at ambient 
temperature up to the reflux temperature for one to twenty-four hours. In 
some cases, the product precipitates from the reaction mixture and can be 
removed by filtration. The product is stirred in dilute mineral acid, 
filtered and washed with cold water. If the product does not precipitate 
from the reaction mixture it can be isolated by evaporation of the 
solvent, trituration of the residue with dilute mineral acid and filtering 
off the insoluble product. 
The heterocyclic isothiocyanates which are used in the procedure of 
Equation 8 are prepared, for example, according to the method of Japan 
Patent Application Pub: Kokai 51-143686, June 5, 1976, or that of W. 
Abraham and G. Barnikow, Tetrahedron 29, 691-7 (1973). 
Agriculturally suitable salts of compounds of Formula I are also useful 
herbicides and can be prepared in a number of ways known to the art. For 
example, metal salts can be made by treating compounds of Formula 1 with a 
solution of an alkali or alkaline earth metal salt having a sufficiently 
basic anion (e.g. hydroxide, alkoxide, carbonate or hydride) quaternary 
amine salts can be made by similar techniques. Detailed examples of such 
techniques are given in U.S. Pat. No. 4,127,405, the disclosure of which 
is herein incorporated by reference.