PROCESS FOR THE PREPARATION OF ARYLOXYBENZOIC ACIDS CONTAINING A SULPHONAMIDE GROUP

PREPARATION D'ACIDES ARYLOXYBENZOIQUES RENFERMANT UN GROUPE SULFONAMIDE

English Abstract

ABSTRACT
"PROCESS FOR THE PREPARATION OF ARYLOXYBENZOIC ACIDS
CONTAINING A SULPHONAMIDE GROUP"
Process for the preparation of an N-sulphonyl-
aryloxy benzamide by reacting an aryloxybenzoic acid with
a sulphonyl isocyanate or isothiocyanate.

Claims

- 9 -
The embodiment of the invention, in which
an exclusive privilege or property is claimed, are defined
as follows:
1. A process for the preparation of a compound
of the general formula:
<IMG>
wherein A is hydrogen, fluorine,
chlorine, bromine, iodine or a nitro group; -N=NCF3: N?; a
dialkylamino group; an alkyl group; trialkylammonio;
alkylthio, alkylsulphinyl, alkylsulphonyl, dialkyl-
sulphonio, cyanosulphonyl, alkanoyloxy, alkoxy, alkoxy
which is substituted by alkoxycarbonyl, nitroso, -SCN,
azide, CF3, -N=N-?-(OCH3)2 or acyl; Z is hydrogen,
fluorine, chlorine, bromine, iodine or an alkyl, alkoxy,
alkylsulphinyl, alkylsulphonyl, CF3, NO2 or CN group; Z1
is hydrogen or halogen, or an alkyl or dialkylamino group,
D is fluorine, chlorine, bromine or iodine, or a CF3,
alkylthio, alkylsulphinyl, alkylsulphonyl, halogenoalkyl,
sulphamyl, formyl, alkylcarbonyl, CN or dimethylamino
group; E is hydrogen or a halogenoalkyl, alkoxy,
alkylsulphinyl, alkylsulphonyl, CN or CF3 group; W is a
trivalent nitrogen atom or a -C(G)= group; G has one of
the meanings given for Z; and R3 is a phenyl, pyridyl or

- 10 -
thienyl group which is optionally substituted by one or
more halogen atoms, alkyl groups or nitro groups, or is
an alkenyl or alkynyl radical having 2 to 4 carbon atoms
or an alkyl radical of 1 to 4 carbon atoms, which are
optionally substituted by one or more fluorine, chlorine,
bromine or iodine atoms, or by one or more of the
following substituents: alkoxycarbonyl of 2 to 5 carbon
atoms, alkylcarbonyl of 2 to 5 carbon atoms,
dialkylcarbamyl in which the alkyl groups have from 1 to 4
carbon atoms, alkylthio, alkylsulphinyl or alkylsulphonyl,
each having 1 to 4 carbon atoms, alkylcarbonyloxy of 2 to
5 carbon atoms or cyano, which comprises reacting an acid
of the general formula:
<IMG> (IV)
with a sulphonyl isocyanate or isothiocyanate of the
general formula:
R3SO2-N=C=Y (V)
wherein Y is an oxygen or sulphur atom and the symbols
A, Z, Z1, D, E, W and R3 are as hereinbefore defined.
2. A process according to claim 1 wherein R2
represents CF3.

- 11 -
3. A process according to claim 1 or 2, wherein
the reaction is carried out in the liquid phase at a
temperature such that the compound COY formed during the
reaction is eliminated from the reaction mixture
progressively, in gaseous form.
4. A process according to claim 1, wherein
the reaction is carried out in the presence of a catalyst.
5. A process according to claim 4 wherein the
catalyst is a tertiary amine or an alkyl-tin salt.
6. A process according to claim 4 or 5 wherein
the molar ratio of catalyst to acid of general formula
(IV) is between 0.001:1 and 0.1:1.
7. A process according to claim 4 or 5 wherein the
molar ration of catalyst to acid of general formula (IV) is
between 0.01:1 and 0.05:1.
8. A process according to claim
1 wherein the molar ration of acid of general formula (IV)
to sulphonyl isocyanate or isothiocyanate of general
formula (V) is between 0.8:1 and 1.2:1.
9. a process according to claim 1
wherein the molar ratio of acid of general formula (IV) to
sulphonyl isocyanate or isothiocyanate of general formula
(V) is between 0.9:1 and 1.1:1.
10. A process according to claim 1
wherein the acid of general formula (IV) and the
sulphonyl isocyanate or isothiocyanate of general formula
(V) are used in stoichiometric proportions.

- 12 -
11. A process according to claim
1 wherein the reaction is carried out in an inert aprotic
organic solvent having a boiling point greater than or
equal to the reaction temperature.
12. A process according to claim 11 wherein the
solvent is an aliphatic or aromatic liquid hydrocarbon
or an ether or nitrile.
13. A process according to claim 11 or 12 wherein
the reaction temperature is less than or equal to the
boiling point of the solvent.
14. A process according to claim 11 or 12 wherein
the reaction temperature is between 60 and 180°C.
15. A process according to claim 11 or 12 wherein
the reaction temperature is between 70 and 150°C.
16. A process according to claim
1 wherein in general formula (I), (IV) and (V) depicted
in claim 1, A is a hydrogen or chlorine atom or an NO2
group, Z is a halogen atom, Z' and E are hydrogen atoms,
D is CF3, R3 is an alkyl group and W is -CH=.
17. A process according to claim 16 wherein R3 is
an alkyl group having 1 to 4 carbon atoms.
18. A process according to claim 16 wherein R3 is
CH3.

Description

~2~S;~57
DESCRIPTION
PROCESS FOR THE PREPARATION OF ARYLOXYBENZOIC ACIDS
_ CONTAINING A SULPHONAMIDE GROUP _ _ _
The present invention relates to an improved
process for the preparation of certain aryloxybenzoic acid
derivatives containing a sulphonamide group and having
herbicidal properties.
Herbicidal derivatives of aryloxybenzoic acids
containing a sulphonamide group (or N-sulphonyl-phenoxy-
benzamides) are known from European Patent Applications
3,416 and 23,392 and Japanese Patent Application No.
82.106,654.
These patent applications disclose many compounds
of this type, in particular compounds of the general formula:
zl z CO-NH-SO -R3
D~ ~ ~ A (I)
E W
and salts thereof, wherein A is hydrogen, fluorine,
15 chlorine, bromine, iodine or a nitro group; -N=NCF3; N2; a
dialkylamino group; an alkyl group; trialkylammonio;
alkylthio, alkylsulphinyl, alkylsulphonyl, dialkylsulphonio,
cyanosulphonyl, alkanoyloxy, alkoxy, alkoxy which is
substituted by alkoxycarbonyl, nitroso, -SCN, azide, CF3,
20 -N=N-~-(OCH3)2 or acyl; Z is hydrogen, fluorine, chlorine,
o

:~2~S~5~7
bromine, iodine or an alkyl, alkoxy, alk~lsulphinyl,
alkylsulphonyl, CF3, N02 or CN group; ~ is hydrogen or
halogen, or an alkyl or dialkylamino group, D is fluorine,
chlorine, bromine or iodine, or a CF3, alkylthio,
5 alkylsulphinyl, alkylsulphonyl, halogenoalkyl, sulphamyl,
formyl, alkylcarbonyl, C~ or dimethylami~o group; E is
hydrogen or a halogenoalkyl, alkoxy, alkylsulphinyl,
alkylsulphonyl, CN or CF3 group, W is a trivalent nitrogen
atom or a -C(G)=group; G has one of the meanings given for
10 Z, and R3 is a phenyl, pyridyl or thienyl group which is
optionally substituted by one or more halogen atoms, alkyl
groups or nitro groups, or is an alkenyl or alkynyl radical
of 2 to 4 carbon atoms or an alkyl radical of 1 to 4 carbon
atoms, which are optionally substituted by one or more
15 fluorine, chlorine, bromine or iodine atoms, preferably CF3,
or by one or more of the following substituents: alkoxycar-
bonyl of 2 to 5 carbon atoms, alkylcarbonyl of 2 to 5 carbon
atoms, dialkylcarbamyl in which the alkyl groups have from
1 to 4 carbon atoms, alkylthio, alkylsulphinyl or alkyl-
20 sulphonyl, each having 1 to 4 carbon atoms, alkylcarbony-
loxy of 2 to 5 carbon atoms or cyano.
In this spécification and the accompanying claims,
alkyl groups and moieties, unless otherwise specified, are
straight or branched-chain and preferably contain from 1 to
25 4 carbon atoms.
According to the known processes, the compounds of

lZ~i35'7
-- 3 --
general formula (I~ CaQ be prepared by reacting an
intermediate acid halide of the formula:
zl z COX
D ~ 0 ~ (II)
E
5 wherein X is chlorine, bromine or iodine and A, z, zl, D,
E and W are as hereinbefore defined, with a sulphonamide
of the general formula:
R S2N~2 (III)
wherein R3 is as hereinbefore defined, at between 25 and
10 140C, generally in the presence of an acid acceptor, in
particular a tertiary amine, such as N,N-dimethylaniline
or pyridine, or an alkali metal carbonate, such as
anhydrous potassium carbonate or an alkali metal fluoride
such as cesium fluoride.
The compounds of general formula (I) can then be
alkylated in a known manner, for example by reaction with
a diazoalkane having 1 to 4 carbon atoms, in a manner such
that the corresponding products substituted by an alkyl
group of 1 to 4 carbon atoms on the nitrogen atom of the
20 sulphonamide group are obtained, the hydrogen atom of
this same nitrogen atom may also be replaced by alkali
mPtal atoms, such as sodium, for example by the action of
a basic alkaline agent to give alkali metal salts of
ccmpounds of general formula (I).

12:1S;~S7
-- 4 --
This known process for condensation of compounds of
the general formulae (II) and (III) has various
disadvantages, in particular mediocre yields. It is
believed that it is generally the presence of an acid
5 acceptor which decreases the yield since it promotes the
diacylation reaction. Moreover, the use of an acid
acceptor renders isolation and purification of the final
products more difficult and more expensive.
Another disadvantage of the known process is that
10 a supplementary reaction stage is necessary to obtain the
acid halide of general formula (II) starting from the acid
of general formula (IV) defined hereinafter.
An object of the present invention is to overcome
the disadvantages of the known processes. Other
15 advantages will appear in the course of the description
which follows.
The present invention provides a process for the
preparation of a compound of general formula (I) wherein
the various symbols are as hereinbefore defined which
20 comprises reacting an acid of the general formula:
zl z COOH
~ ~ (IV)
D ~ ~ ~ O ~ A
E~W
with a sulphonyl isocyanate or isothiocyanate of the
general formula:

3 Z~5357
R S02-N=C-Y (V)
wherein Y is an oxygen or sulphur atom and the s~mbols A,
Z, Z , D E, W, and R3 are as hereinbefore defined. This
process is in general effected in the liquid phase,
5 preferably in the presence of a catalyst, and at a
temperature such that the compound COY (that is to say
carbon dioxide, if Y - 0, or carbonyl sulphide, if Y = S)
which forms during the reaction is eliminated from the
reaction mixture progressively, in gaseous form.
A sub-group of compounds of general formula (I)
which are particularly appropriately and advantageously
prepared by the process according to the present invention
comprises the compounds of general formula (I) wherein A
is a hydrogen atom, an N02 group or a chlorine atom; Z is
15 a halogen atom, more especially chlorine; zl and E are
hydrogen atoms, D is the CF3 group, R3 is an alkyl group,
preferably having 1 to 4 carbon atoms, especially CH3, and
W is -CH=, and more especially 5-[2'-chloro-4'-
(trifluoromethyl)-phenoxy~-2-nitro-N-methanesulphonyl-
20 benzamide.
The preferred reactants of general formulae (IV)and (V) are chosen in such a way that the symbols present
in their formulae have meanings corresponding to those
given hereinbefore for the compounds of general formula
25 (I).
Of the catalysts which can be used, there may be

~Z~3S~
mentioned non-limitatively: tertiary amines, such as
triethylamine, pyridine, N,~-dimethylaniline or 1,4-di-
azabicyclo(2,2,2) octane, or tin derivatives, in
particular alkyl-tin salts, such as dibutyl-tin diacetate
5 or dibutyl-tin dilaurate. Tertiary amines and alkyl-tin
salts are preferred.
The molar ratio Df the compound of general formula
(IV) to the compound of general formula ~V) is generally
between 0.8:1 and 1.2:1, preferably between 0.9:1 and
10 1.1:1; more especially these reagents are used in
stoichiometric proportions.
The molar ratio of catalyst to acid of general
formula (IV) in general varies between 0.001:1 and 0.1:1,
and is preferably between 0.01:1 and 0.05:1.
The reagents are preferably dissolved in an inert
aprotic organic solvent having a boiling point greater
than or equal to the reaction temperature, for example an
aliphatic or aromatic, chlorinated or non-chlorinated
liquid hydrocarbon, such as benzene, toluene, the xylenes,
20 xylene mixtures, 1,2-dichloroethane or chlorobenzene, or
an ether or nitrile: it is also possible to use a mixture
of several solvents. The use of an inert solvent has the
practical advantage of allowing better transfer of heat in
a process carried out on an industrial scale: it also
25 enables local overheating of the reaction mixture to be
avoided.

~s~
-- 7 --
As hereinbefore indicated, t~e temperature at which the
process according to the present invention is carried out
is advantageously such that the compound of the formula
COY (carbon dioxide or carbonyl sulphide) formed in the
5 course of the reaction is eliminated f~om the reaction
mixture in gaseous form progressively as it is generated.
Moreover, this temperature is lower than the decomposition
temperature of the compounds of general formulae (IV), (V)
and (I) i-nvolved in the process. In the case where a
10 solvent is used, the reaction temperature is advantageously
less than or equal to the boiling point of the solvent
and is generally between 60 and 180C and preferably
between 70 and 150C.
At the end of the reaction, the compound of general
15 formula (I) can be isolated by methods ~nown ~ se. By
the term "methods kno~n per se" as used in the present
specification is meant methods herQtofore used or
described in the chemical literature.
The process according to the present invention is
20 distinguished by the simplicity of the method of recovery
of the end product, since this product is generally
insoluble in the hot reaction mixture and separates out as
crystals in a pure form, so that this recovery is
essentially reduced to filtration. This filtration can
25 also be facilîtated by addition of a non-solvent.
The following non-limitative examples illustrate

~Z~L5357
the present invention.
Example 1
5 g (0.0138 mol) of 5-[2'-chloro-4'-
(trifluoromethyl)-phenoxy]-2-nitrobenzoic acid are
5 suspended in 10 cm3 of toluene. The suspension is stirred
and 1.9 g tO.0138 mol) of methanesulphonyl isothiocyanate
and 0.04 g (0.0004 mol) of triethylamime are added at room
temperature~ The reaction mixture is heated, with
stirring and while boiling under reflux, for 10 minutes.
10 Carbonyl sulphide escapes from the reaction mixture
progressively as it is formed. After addition of 20 cm3
of toluene, the precipitate formed is filtered off and
washed with toluene and then with methylene chloride.
5 g (0.0114 mol, 83% yield) of a white solid
15 consisting of 5-~2'-chloro-4'-(trifluoromethyl)-phenoxy]-
2-nitro-N-methanesulphonylbenzamide of melting point 218C
are thus obtained. The structure of this product is
confirmed by infra-red and nuclear magnetic resonance
spectroscopy.
Example 2
Proceeding as described in Example 1 but replacing
the 1.9 g of methanesulphonyl isothiocyanate by 1,7 g of
methanesulphonyl isocyanate (CH3S02N=C=0), 5-[2'-
chloro-4'-(trifluoromethyl)-phenoxy]-2-nitro-~-
25 methanesulphonylbenzamide is obtained in a yield of 88%.