Process for producing arylsulfamates

The present invention relates to a novel process for producing 
N-(heterocyclo-aminocarbonyl)-arylsulfamates. 
N-(Heterocyclo-aminocarbonyl)-arylsulfamates are known as being herbicides 
for pre- and post-emergence application. Herbicidal active substances of 
this type, their production, compositions containing them and the use 
thereof are described in the U.S. Pat. No. 4,191,553. 
According to the production process described in the U.S. Pat. No. 
4,191,553, the herbicidal N-(heterocyclo-aminocarbonyl)-arylsulfamates are 
obtained by firstly refluxing phenols with chlorosulfonylisocyanate in 
toluene or xylene for 11/2 to 2 hours, and isolating the intermediate 
reaction product. The formed aryloxysulfonylisocyanate is reacted, in a 
second reaction step, with a triazinyl- or pyrimidinylamine. The known 
2-stage process is disadvantageous in that, with the formation of the 
aryloxysulfonyl-isocyanate-starting product by heating at temperatures of 
110.degree.-140.degree. C., there can always occur, as by-products, 
3-oxo-2,3-dihydro-4,1,2-benzoxathiazine-1,1-dioxide derivatives when the 
employed phenols have a free ortho-position [cp. Chem. Ber. 105, 2791 
(1972)]. Furthermore, it is possible under the applied reaction conditions 
for substituents of the phenol ring which are sensitive to acid to become 
decomposed by the formed hydrogen chloride. And, finally, the performed 
process is uneconomical also in view of the necessary heating of the 
reaction mixture in the first step. 
The object of the present invention was thus to avoid the disadvantages of 
the known process, and to provide a process by which 
N-(heterocycloaminocarbonyl)-arylsulfamates can be produced on a 
commercial scale in a simple, unequivocal and economical manner. 
According to the process of the invention, the herbicidal 
N-(heterocyclo-aminocarbonyl)-arylsulfamates of the general formula I 
##STR4## 
wherein R.sub.1 is hydrogen, methoxy or C.sub.1 -C.sub.3 -alkyl, 
R.sub.2 is hydrogen, fluorine, chlorine, bromine, nitro, CF.sub.3, C.sub.1 
-C.sub.4 -alkyl, C.sub.1 -C.sub.4 -alkoxy or C.sub.1 -C.sub.4 
-alkoxycarbonyl, 
R.sub.3 is hydrogen, fluorine, chlorine, bromine, methyl or C.sub.1 
-C.sub.4 -alkoxy, 
R.sub.4 is hydrogen, fluorine, chlorine, bromine, nitro, cyano, C.sub.1 
-C.sub.4 -alkyl, C.sub.1 -C.sub.4 -alkoxy or C.sub.1 -C.sub.4 
-alkoxycarbonyl, 
R.sub.5 is hydrogen, fluorine, chlorine, bromine, nitro or CF.sub.3, 
R.sub.6 is hydrogen, fluorine, chlorine, bromine, C.sub.1 -C.sub.4 -alkyl 
or C.sub.1 -C.sub.4 -alkoxy, 
X is C.sub.1 -C.sub.2 -alkyl, C.sub.1 -C.sub.3 -alkoxy, C.sub.1 -C.sub.2 
-alkylthio, methoxymethyl, methoxyethyl, CF.sub.3 or chlorine, 
Y is C.sub.1 -C.sub.2 -alkyl, C.sub.1 -C.sub.3 -alkoxy, C.sub.1 -C.sub.2 
-alkylthio, methoxymethyl or methoxyethyl, and 
Z is the methine group or nitrogen, 
are obtained by adding, in a single-vessel process, in an inert organic 
solvent, chlorosulfonylisocyanate of the formula III 
EQU Cl--SO.sub.2 --N.dbd.C.dbd.O (III) 
to an aminoheterocyclic compound of the formula II 
##STR5## 
wherein R.sub.1, X, Y and Z have the meanings defined under the formula I; 
and subsequently reacting this mixture, optionally with the addition of an 
agent binding hydrogen chloride, with a phenol of the formula IV 
##STR6## 
wherein R.sub.2 and R.sub.3 have the meanings given under the formula I. 
The process according to the invention is exothermic, so it can therefore 
be necessary to cool the reaction vessel. The process is carried out at 
temperatures of between -10.degree. C. and +80.degree. C., preferably 
between 0.degree. C. and 40.degree. C. 
Suitable inert organic solvents which can be used are: hydrocarbons, such 
as benzene, toluene, xylene or cyclohexane; chlorinated hydrocarbons, such 
as methylene chloride, chloroform, carbon tetrachloride or chlorobenzene, 
and ethers, such as diethyl ether, dimethoxyethane, diethylene 
glycol-dimethyl ether, tetrahydrofuran or dioxane. Preferred solvents are 
cyclic or polyvalent ethers, such as tetrahydrofuran, dioxane or 
dimethoxyethane. 
Suitable agents binding hydrogen chloride are carbonates and hydrogen 
carbonates of alkali metals and alkaline-earth metals, such as sodium and 
potassium carbonate and sodium and potassium hydrogen carbonate, or 
tertiary amines, such as pyridine, 4-dimethylaminopyridine, quinoline, 
isoquinoline, quinuclidine, triethylamine or trimethylamine. 
Chlorosulfonylisocyanate is used according to the invention in an equimolar 
amount or in a slight excess. It is advantageous to use 1.0 to 1.3 mols of 
chlorosulfonylisocyanate per mol of aminoheterocyclic compound. The amount 
preferably used in 1.0 to 1.2 mols, depending on the degree of purity of 
the chlorosulfonylisocyanate. On account of the high reactivity of the 
chlorosulfonylisocyanate, it is of advantage to use solvents which are 
free from water and alcohol. 
In a preferred embodiment of the process according to the invention, the 
heterocycloamine of the formula II is suspended in absolute dioxane, and 
at 5.degree.-10.degree. C. are added, with cooling, 1.0-1.2 mols of 
chlorosulfonylisocyanate per mol of aminoheterocyclic compound. To the 
formed clear solution is added 0.9-1.0 mol of the phenol of the formula IV 
per mole of aminoheterocyclic compound. There is optionally added to the 
solution 1 mol of triethylamine in such a manner that the temperature of 
the reaction mixture does not exceed 25.degree. C. After the reaction 
mixture has been stirred at 20.degree.-25.degree. C. until the reaction of 
the starting materials is completed, the solvent, after filtration, is 
evaporated off, and the product is obtained by crystallisation of the 
residue. 
It is possible by the process according to the invention to produce 
N-(heterocycloamino-carbonyl)-arylsulfamates on a commercial scale in a 
simple, clear and economical manner. The process avoids the isolation of 
an intermediate, a step which is necessary in the known process, and 
requires no heating of the reaction mixture. Also avoided by the process 
of the invention is the formation to by-products, even when the 
ortho-position of the phenol ring is unoccupied and when the phenol ring 
carries substituents sensitive to acid, because the process according to 
the invention can be performed at considerably lower temperatures. 
By the reaction of chlorosulfonylisocyanate (III) with an amine of the 
formula II intermediates of the formula V are formed 
##STR7## 
wherein X, Y and Z have the meaning given under the formula I. 
These intermediates of the formula V are part of the invention. 
Examples of the intermediates of the formula V are listed below. 
N-(4-methoxy-6-methyl-1,3,5-triazin-2-yl)-N-chlorosulfonylurea, mp. 
79.degree. C. (dec.), 
N-(4,6-dimethyl-1,3,5-triazin-2-yl)-N'-chlorosulfonyl-urea, 
N-(4,6-dimethoxy-1,3,5-triazin-2-yl)-N'-chlorosulfonylurea, 
N-(4-methoxy-6-methyl-pyrimidin-2-yl)-N'-chlorosulfonylurea, 
N-(4,6-dimethoxy-pyrimidin-2-yl)-N'-chlorosulfonyl-urea, 
N-(4,6-dimethyl-pyrimidin-2-yl)-N'-chlorosulfonyl-urea, 
N-(4-methyl-6-methylthio-1,3,5-triazin-2-yl)-N'-chlorosulfonyl-urea, 
N-(4-methoxymethyl-6-methyl-1,3,5-triazin-2-yl)-N'-chlorosulfonyl-urea, 
N-(4-ethyl-6-methoxy-pyrimidin-2-yl)-N'-chlorosulfonyl-urea, 
N-(4-methoxy-6-trifluoromethyl-1,3,5-triazin-2-yl)-N'-chlorosulfonyl-urea 
and 
N-(4-chloro-6-methyl-pyrimidin-2-yl)-N'-chlorosulfonyl-urea. 
The intermediate compounds of the formula V can be obtained from a reaction 
which is carried out according to the first part of the inventive process 
and isolation of the formula V compounds by evaporating off the solvent. 
Instead of isolating the intermediates it is particularly preferable to 
produce these compounds in situ and to directly convert them to the end 
products of the formula I by adding phenols of the formula IV thereto 
according to the single vessel process of the invention.

The process according to the invention is further illustrated by the 
following Examples. 
EXAMPLE 1 
N-[(4-Methoxy-6-methyl-1,3,5-triazin-2-yl)aminocarbonyl]-0-phenylsulfamate 
##STR8## 
8.1 g (57.5 mmols) of chlorosulfonylisocyanate are added dropwise to a 
suspension, cooled to 5.degree. C., of 7.0 g (50 mmols) of 
2-amino-4-methoxy-6-methyl-1,3,5-triazine in 100 ml of abs. dioxane. When 
a clear solution has formed after about 10 minutes, 4.7 g (50 mmols) of 
phenol are added, as a result of which the temperature of the solution 
rises to 8.degree. C. There are subsequently added dropwise to the 
solution, with slight cooling, 6.9 ml (50 mmols) of triethylamine in such 
a manner that the temperature of the reaction mixture does not exceed 
25.degree. C. After 16 hours of stirring at room temperature, the 
suspension is filtered through a short silica gel column. Concentration by 
evaporation of the clear yellow solution produces 12.5 g (74%) of 
N-[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)-amino-carbonyl]-O-phenylsulfama 
te, which yields, after recrystallisation from an ether/benzine mixture, 
colourless crystals, m.p. 152.degree.-153.degree. C. 
EXAMPLE 2 
N-[(4,6-Dimethyl-pyrimidin-2-yl)-amino-carbonyl]-O-(2-chlorophenyl)-sulfama 
te 
##STR9## 
To a slightly cloudy solution, cooled to 5.degree.-10.degree. C., of 3.7 g 
(30 mmols) of 2-amino-4,6-dimethyl-pyrimidine in 25 ml of absolute dioxane 
are added dropwise 3.1 ml (35.4 mmols) of chlorosulfonylisocyanate. 
Immediately after the addition of the chlorosulfonylisocyanate, 2.9 ml 
(27.5 mmols) of 2-chlorophenol are added to the formed clear solution. 
After a stirring time of 16 hours and concentration by evaporation, the 
oily residue is taken up in a small amount of methylene chloride, and the 
suspension is filtered through a short silica gel column. The solution is 
concentrated by evaporation to obtain 8.2 g (76.6%) of 
N-[(4,6-dimethyl-pyrimidin-2-yl)aminocarbonyl]-O-(2-chlorophenyl)-sulfamat 
e, which, after recrystallisation from an ether/benzine mixture, yields 
colourless crystals, m.p. 145.degree.-147.degree. C. 
Further compounds of the formula I can be obtained in an analogous manner, 
for example those listed in the U.S. Pat. No. 4,191,553.