PROCEDE DE PREPARATION D'ACIDES ARYLOXYBENZOIQUES CONTENANT LE GROUPE SULPHONAMIDE

PROCESS FOR THE PREPARATION OF ARYLOXYBENZOIC ACIDS CONTAINING A SULPHONAMIDE GROUP

Abrégé anglais

ABSTRACT
A PROCESS FOR THE PREPARATION OF ARYLOXYBENZOIC ACIDS
CONTAINING A SULPHONAMIDE GROUP
A process for the preparation of herbicidal
aryloxybenzoic acids containing a sulphonamide group by
reacting an aryloxybenzoic acid halide, which may be impure,
with a sulphonamide in the presence of a halogenating agent
such as P(0)C13.

Revendications

- 16 -
The embodiments 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>
(I)
in which:
A is hydrogen; fluorine; chlorine; bromine; iodine; a
nitro group; -N=NCF3; H2PO3 and its alkyl esters wherein the
alkyl group contains from 1 to 4 carbon atoms; NH2; NHOH; N?;
a carboxy group or one of its functional derivatives; a
monoalkylamino or dialkylamino group; an NH-CO-R1 group in
which R1 is an alkyl or alkoxy or monoalkylamino or
dialkylamino group; an alkyl group; trialkylammonium; NHSO2R2
in which R2 is an alkyl group or a phenyl group; NHCONHSO2R2,
in which R2 is as hereinbefore defined; alkylthio;
alkylsulphinyl; alkylsulphonyl; dialkylsulphonium;
cyanosulphonyl; hydroxy; alkanoyloxy; alkoxy, alkoxy
substituted by an alkoxycarbonyl group; SH; nitroso; -SCN;
azide; CF3; <IMG> or acyl;

- 17 -
B is a hydrogen, fluorine, chlorine, bromine or iodine atom,
or an alkyl, alkoxy, alkylsulphinyl, alkylsulphonyl, CF3,
NO2, CN, NH2, NHCOR wherein R1 is as hereinbefore defined or
CONH2 group;
C is a hydrogen or halogen atom or an alkyl or
dialkylamino group;
D is a fluorine, chlorine, bromine or iodine atom or a
CF3, alkylthio, alkylsulphinyl, alkylsulphonyl, haloalkyl,
sulphamoyl, formyl, alkylcarbonyl, CN or dimethylamino group,
E is hydrogen or a haloalkyl, alkoxy, alkylsulphinyl,
alkylsulphonyl, CN, CF3, NH2, CONH2, or NH-CO-R1 group,
wherein R1 is as hereinbefore defined;
W is a trivalent nitrogen atom or a -C(G)= group in which
G has one of the meanings given for B;
R3 is a phenyl, pyridyl or thienyl group optionally
substituted by one or more halogen atoms, alkyl groups or
nitro groups; or an alkenyl or alkynyl radical having 2 to 4
carbon atoms or an alkyl radical containing 1 to 4 carbon
atoms optionally substituted by one or more fluorine,
chlorine, bromine or iodine atoms, or by one or more of the
following substituents: carboxy, alkoxycarbonyl containing
from 2 to 5 carbon atoms, alkylcarbonyl containing from 2 to
5 carbon atoms, monoalkylcarbamoyl or dialkylcarbamoyl in
which the alkyl groups contain from 1 to 4 carbon atoms,
alkylthio, alkylsulphinyl, alkylsulphonyl, each having from 1
to 4 carbon atoms, alkylcarbonyloxy containing from 2 to 5
carbon atoms, alkylcarbonylamino containing from 2 to 5
carbon atoms, or cyano, which comprises reacting an acid

- 18 -
halide of the general formula:
<IMG>
(II)
with a sulphonamide of the general formula:
R3-SO-2-NH2 (III)
in which A, B, C, D, E and W are as hereinbefore defined, and
X is chlorine, bromine or iodine, in the liquid phase in the
presence of a halogenating agent and at a temperature such
that the hydrogen halide formed during the reaction is
removed progressively from the reaction medium in a gaseous
form as it is formed.
2. A process according to claim 1 wherein R3
represents CF3.
3. A process according to claim 1 or 2 in which A is
NO2 or a hydrogen or chlorine atom B is a halogen atom, C and
are hydrogen atoms, D is a trifluoromethyl group, and W is
-CH=.
4. A process according to claim 1 in which
is a chlorine atom and R3 is an alkyl group.
5. A process according to claim 1 in
which R3 is an alkyl group containing from 1 to 4 carbon
atoms.
6. A process according to claim 1 in
which R3 is CH3.
7. A process according to claim 1,
wherein X in the compound of general formula (II) is a
chlorine atom.

- 19 -
8. A process according to claim 1, in
which the starting material comprises, in addition to the
acid halide of general formula (II), up to 30% by weight of
impurities.
9. A process according to claim 1 in
which the starting material comprises, in addition to the
acid halide of general formula (II), up to 20% by weight of
impurities.
10. A process according to claim 1,
wherein the starting material comprises, in addition to the
acid halide of general formula (II), impurities which are
mainly compounds containing a group of the formula:
<IMG>
which carries one or more substituents.
11. A process according to claim 10, in which the
starting material comprises, in addition to the acid halide
of general formula (II), impurities which are mainly
compounds containing a group of the formula:
<IMG>
which carries one or more substituents.
12. A process according to claim 1,
in which the halogenating agent is P(0)C13, PC13, P(0)Br3, or
PBr3.
13. A process according to claim 1,
in which the halogenating agent is P(0)C13.
14. A process according to claim 1,
which is carried out in the absence of an acid acceptor.

- 20 -
15. A process according to claim 1,
in which the molar ratio of the sulphonamide of general
formula (III) depicted in claim 1 relative to the acid halide
of general formula (II) depicted in claim 1 is between 0.8
and 1.2.
16. A process according to claim 1,
in which the molar ratio of the sulphonamide of general
formula (III) depicted in claim 1 relative to the acid halide
of general formula (II) depicted in claim 1 is between 0.9
and 1.1.
17. A process according to claim 1 in
which the molar ratio of the halogenating agent relative to
the acid halide of general formula (II) depicted in claim 1
is between 0.1 and 20.
18. A process according to claim 1 in
which the molar ratio of the halogenating agent relative to
the acid halide of general formula (II) depicted in claim 1
is between 0.1 and 5.
19. A process according to claim 1,
which is carried out in the presence of an inert solvent.
20. A process according to claim 19, in which the
solvent is a liquid aliphatic or aromatic, chlorinated or
non-chlorinated hydrocarbon, or a nitrile.
21. A process according to claim 1,
in which the reaction temperature is below the decomposition
temperature of the compounds of general formulae (III), (II)
and (I) and, if appropriate, less than or equal to the

- 21 -
boiling point of the solvent used.
22. A process according to claim 21, in which the
reaction temperature is between 70 and 180°C.
23. A process according to claim 21 in which the
reaction is carried out in the absence of a solvent and
the reaction temperature is between 80 and 120°C.
24. A process according to claim 21 in which the
reaction is carried out in the presence of a solvent and
the reaction temperature is between 80 and 150°C.

- 22 -
CLAIMS SUPPORTED BY THE SUPPLEMENTARY DISCLOSURE
25. A process according to Claim 1 in which, in general
formulae (I) and (II), A is hydrogen, B is chlorine, C is
hydrogen, D 13 trifluoromethyl, E is hydrogen, W is a -C(H)-
group, X in general formula (II) is chlorine, and R3 in
formulae (I) and (III) is methyl.
26. A process according to Claim 25 in which the
halogenating agent is phosphoryl chloride.

Description

1~30593
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 phenoxybenzoic acid derivatives
containing a sulphonamide group (or N-sulphonylphenoxy-
benzamides) are known from European Patent Applications Nos.
3,416 and 23,392 and Japanese Patent Application No.
82/106,654.
These patent applications disclose a number of
products of this type, and particularly products of the
general formula:
C B Co-NH-So2-R3
D ~ O ~ (I)
and their salts,
in which:
A is hydrogen; fluorine; chlorine; bromine; iodine; a nitro
group; -N=NCF3;H2PO3 and its alkyl esters wherein the alkyl
group contains from 1 to 4 carbon atoms; NH2; NHOH; N2; a
carboxy group or one of its functional derivatives (e.g.
esters,
amides and alkali metal, alkaline earth metal, ammonium and

1230593
-- 2 --
amine salts); a monoalkylamino or dialkylamino group; an
NH-CO-Rl group in which Rl is an alkyl or alkoxy or
monoalkylamino or dialkylamino group; an alkyl group;
trialkylammonium; NHSO2 in which R2 is an alkyl group or a
phenyl group; NHCONHSO2R2, in which R2 is as hereinbefore
defined; alkylthio; alkylsulphinyl: alkylsulphonyl;
dialkylsulphonium; cyanosulphonyl; hydroxy; alkanoyloxy;
alkoxy; alkoxy substituted by an alkoxycarbonyl group; SH;
nitroso ; -SCN; an azide group; CF3; -N=N-P-(OCH3)2,
o
or acyl;
B is a hydrogen, fluorine, chlorine, bromine or iodine
atom, or an alkyl, alkoxy, alkylsulphinyl, alkylsulphonyl,
CF3, NO2, CN, NH2, NHCORl, wherein R is as hereinbefore
defined, or CONH2 group;
C is a hydrogen or halogen atom or an alkyl or
dialkylamino group;
D is a fluorine, chlorine, bromine or iodine atom or a
CF3, alkylthio, alkylsulphinyl, alkylsulphonyl, haloalkyl,
sulphamoyl, formyl, alkylcarbonyl, CN or dimethylamino group;
E is hydrogen or a haloalkyl, alkoxy, alkylsulphinyl,
alkylsulphonyl, CN, CF3, NH2, CONH2, or NH-CO-Rl group, in
which Rl is as hereinbefore defined;
W is a trivalent nitrogen atom or a -C(G)= group in which
G has one of the meanings given for B;
R3 is a phenyl, pyridyl or thienyl group optionally
substituted by one or more halogen atoms, alkyl groups or
nitro groups; or an alkenyl or alkynyl radical having 2 to 4

lZ3(~593
-- 3 --
carbon atoms or an alkyl radical containing 1 to 4 carbon
atoms optionally substituted by one or more fluorine,
chlorine, bromine or iodine atoms, preferably CF3, or by one
or more of the following substituents: carboxy,
alkoxycarbonyl containing from 2 to 5 carbon atoms,
alkylcarbonyl containing from 2 to 5 carbon atoms,
monoalkylcarbamoyl or dialkylcarbamoyl in which the alkyl
groups contain from 1 to 4 carbon atoms, alkylthio, alkyl~
sulphinyl, alkylsulphonyl, each having from 1 to 4 carbon
10 atoms, alkylcarbonyloxy containing from 2 to 5 carbon atoms,
alkylcarbonylamino containing from 2 to 5 carbon atoms, or
cyano.
In this specification and the accompanying claims
alkyl groups and moieties, unless otherwise specified, are
lS straight- or branched-chain and preferably contain from 1 to
4 carbon atoms.
According to the known processes, the products of
general formula (I) can be prepared by reacting, between 25
and 140C, an acid halide intetmediate of the general
formula:
D ~0 ~X ( I l )
in which X is chlorine, bromine or iodine, and A, B, C, D, E
and W have the meanings already indicated, with a
sulphonamide of the general formula:

1230S93
-- 4 --
2 2 (III)
in which R3 is as hereinbefore defined, generally in the
presence of an acid acceptor, especially 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 caesium fluoride.
The compounds of general formula (I) can then be
alkylated in a known manner, for example by reaction with a
diazoalkane containing ~rom 1 to 4 carbon atoms, so as to
give the corresponding products which are substituted on the
nitrogen atom of the sulphonamide group by an alkyl group
containing from 1 to 4 carbon atoms; the hydrogen atom of
this same nitrogen atom can also be replaced by an alkali
metal atom such as, e.g. sodium, for example by reaction with
lS basic alkali metal reagents.
This known process for condensing the compounds of
general formulae (II) and (III) has various disadvantages, in
particular poor yields. It is believed that, in general, it
is the presence of an acid acceptor which lowers the yield
because it favours the diacylation reaction. Moreover, the
use of an acid acceptor makes the isolation and the
purification of the final products more difficult and more
costly.
An objective of the invention is to remedy these
disadvantages of the known processes.
The process of the present invention enables the

lZ3(~S93
-- 5 --
of general formula (I) to be prepared from reactants of the
general formula:
C B COOH
D ~ O ~ A (IV)
(wherein the various symbols are as hereinbefore defined)
of technical or industrial grades.
In practice, the latter problem is all the more
important because this type of acid of general formula (IV)
is liable to contain a considerable number of impurities as a
result of the number and the nature of the reactions used in
its manufacture. Thus, by way of a non-limiting example, it
may be indicated that acifluorfen of the formula:
Cl CooH
CF3~ 0 {~ N02 (V)
i.e. 5-[2'-chloro-4'-(trifluoromethyl)phenoxy]-2-nitrobenzoic
acid, can be prepared by coupling an alkali metal
meta-cresolate with a 3,4-dihalotrifluoromethylbenzene,
followed by oxidation of the CH3 group to a carboxylic acid
group and then nitration. During such a sequence of
reactions, the number of isomers and other undesirable
compounds progressively increases and a large number of acids
is often detected in acifluorfen of ordinary quality, and
especially the following acids:
2-ni~ro-3-12'-chloro-4'-(trifluoromethyl)phenoxy]benzoic acid
in an amount which can easily reach 16~ by weight, 2-nitro-5-

~3~593
-- 6 --
[2'-chloro-5'-(trifluoromethyl)phenoxy]benzoic acid and 4-
nitro-5-[2'-chloro-4'-(trifluoromethyl)phenoxy]benzoic acid,
it being easily possible for these two acids to be present in
quantities of up to 3~ by weight, as well as a series of
other acids, in amounts which can also range up to 3~, this
amount frequently being lower, however, for example less than
0.5~, such as for example the following acids
3-12'-chloro-S'-(trifluoromethyl)phenoxy]benzoic acid,
3-[2'-chloro-4'-(trifluoromethyl)phenoxy]benzoic acid and
2,4-dinitro-5-[2'-chloro-4'-(trifluoromethyl)phenoxy]benzoic
acid, as well as
4-[2'-chloro-4'-(trifluromethyl)phenoxy]nitrobenzene and 2-
nitro-5-[2'-chloro-4'-(trifluoromethyl)phenoxy]toluene.
The process of the invention permits the
preparation of products of general formula (I) having high
purity from starting materials of low purity which comprise
impurities in addition to the compound of general formula
(IV).
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 comprises
reacting an acid halide of general formula (II) with a
sulphonamide of general formula (III), wherein, in both, the
various symbols are as defined and X is preferably a chlorine
atom in the liquid phase, in the presence of a halogenating
agent, preferably a phosphorated chlorinating (or
chloride-forming) agent and at a temperature which is such

123(~593
-- 7 --
that the hydrogen halide which is formed during the reaction
is progressively removed from the reaction medium in a
gaseous form as it is formed.
According to a preferred embodiment of the process
according to the invention, the acid halide of general
formula (II) which is used is one which has been prepared by
halogenating an acid of general formula (IV) by means of a
known halogenating agent.
According to an embodiment of the invention, there
is employed [for reacting with the sulphonamide of general
formula (III)] an acid halide of general formula (II) of
technical or industrial quality, that is to say containing up
to 20% by weight and possibly up to, but preferably less
than, 30% by weight of impurities. Such impurities are, for
example, the impurities derived from the reaction of a
halogenating agent with an acid of general formula (IV) of
technical or industrial quality, containing up to 20% by
weight and possibly up to, but preferably less than, 30~ by
weight of impurities. These impurities in the acid halide of
general formula (II) are, therefore, chiefly products whose
formula is similar to that of the compound of general formula
(II~, but differing particularly in the number and the
position of the substituents. These impurities are therefore
essentially compounds containing the group of the formula:
~ ~ (A)
which carries one or more substituents, or specifically the

lZ305~3
group of the formula:
Cl
~0~ (O
¢F3
which carries one or more additional substituents.
The process of the invention comprising the
reaction of the compounds of general formulae (II) and (III)
is preferably carried out in the absence of an acid acceptor;
furthermore, the presence of a solvent is optional.
A sub-group of compounds of general formula (I) for
the preparation of which the process according to the
invention is especially suitable and advantageous, consists
of the compounds of general formula ~I) in which A is the NO2
group or a hydrogen or chlorine atom; B is a halogen atom and
more particularly a chlorine atom; C and E are hydrogen
atoms; D is the CF3 group; R is an alkyl group preferably
having 1 to 4 carbon atoms, particularly CH3; and W is -CH=,
and more especially 5-[2'choro-4'-(trifluoromethyl)phenoxy]-
2-nitro-~-methanesulphonylbenzamide..
The preferred reactants of general formulae (II)
and ~III) are naturally chosen so that the symbols which
appear in their formula have a meaning which is similar to
that just given for the products of general formula (I).
Among the halogenating agents which may be employed
there may be mentioned: P(O)C13, PC13, P(O)Br3 or PBr3;
P(O)C13 is preferred.
The molar ratio of (II) to (III) is generally

lZ3l:~S93
between 0.8 and 1.2, preferably btween 0.9 and 1.1; more
especially, these reactants are in stoichiometric
proportions.
The molar ratio of the halogenating agent relative
to the halide of general formula (II) generally varies
between 0.1 and 5. The halogenating agent can be present in
large excess, e.g. the molar ratio relative to the acid
halide (II) may exceed 5 and may be as much as 20; it can
then serve as a solvent for the reaction. In that case, it
can be recovered by distillation from the reaction mixture
for the purpose of subsequent recycling.
The reactants can also be dissolved in an inert
solvent which has a boiling point above the reaction
temperature, for example a liquid aliphatic or aromatic,
chlorinated or unchlorinated hydrocarbon such as benzene,
toluene, xylenes, mixed xylenes, cumene, 1,2-dichloro-
ethane, chlorobenzene or, for example, a nitrile such as
acetonitrile; a mixture of several solvents can also be
employed. The use of an inert solvent has the practical
advantage of permitting better heat transfer in a process on
an industrial scale; it also makes it possible to avoid local
overheating of the reaction medium.
As hereinbefore indicated, the temperature at which
the process according to the invention is carried out is such
that the hydrogen halide formed during the reaction is
removed from the reaction medium in a gaseous form
concurrently with its production. This temperature,

~Z3~593
-- 10 --
moreover, lies below the decomposition temperature of the
compounds of general formulae (II), (III) and (I) involved in
the process; in the case where a solvent is employed, the
reaction temperature is advantageously less than or equal to
the boiling point of this solvent which can, moreover,
consist of an excess of the halogenating agent as has already
been indicated. The temperature is therefore generally
between 70 and 180C. In the absence of a solvent, the
preferred temperature is between 80 and 120C: in the
presence of a solvent (particularly in the case of cumene
which boils at 153C), the temperature is advantageously
between 80 and 150C.
At the end of the reaction the product of general
formula (I) can be isolated by methods known per se. By the
term "methods known per se" as used in the present
specification is meant methods heretofore used or described
in the chemical literature.
The process according to the invention is
distinguished by the simplicity of the method by which the
final product is recovered because the latter is insoluble
in the halogenating agent with the result that this recovery
is usually confined to a filtration. This filtration can also
be facilitated by the addition of a non-solvent.
The acid halide of general formula (II) can be
prepared by any method known ~ se from the acid of general
formula (IV). In general, the procedure is a reaction of an
acid of general formula (IV) with a halogenating agent such

123~S93
as those mentioned hereinbefore. ~he reaction can, if
appropriate, be carried out in situ, and catalysts, e.g.
dimethylformamide, can also be employed.
The acid halide of general formu~a (II) can be:
- separated and purified, or
- separated in the crude state without purification, or
- prepared _ situ in the reaction solvent, without being
separated, before being placed in the presence of the
sulphonamide of general formula (III).
The following non-limitative examples illustrate
the present invention.
Example 1:
Cl COCl
CF - ~ - ~ ~ ~ NO2 + CH352NH2 9O~C
Cl CoNHso2cH3
3 ~ ~ ~ ~ NO2 + H Cl
(VI)
5-[2'-Chloro-4'-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid
15 chloride (16.79; 0.044 mol) and methanesulphonamide (4.2 9;
0.044 mol) are suspended in P(0)C13 i.e. phosphoryl chloride
(20 cc). The reaction mixture is heated for 1 hour at 90C
with stirring. After adding toluene (50 cc) the precipitate
formed is filtered off and then washed with toluene.
A white solid consisting of 5-l2'-choro-4'-(tri-
fluoromethyl)phenoxy]-2-nitro-N-methanesulphonyl benzamide
(16.49; 0.034 mol; yield 85%), of the formula (VI), m.p.
203C is thus obtained. The structure of this product is
confirmed by infrared and by nuclear magnetic resonance
(NMR).

123~593
Example 2:
5-C2'-Chloro-4'-~trifluoromethyl)phenoxy~-2-nitro-
benzo;c ac;d chlor;de (19 9; 0.05 mol) and methanesul-
phonamide (4.759; 0.05 mol) are suspended in a mixture
of P(O)Cl3 (14 cc) and toluene (35 cc). The reaction
mixture is heated for 3 hours at 100C ~ith stirring.
After adding toluene (50 cc) the precipitate formed is
filtered off and then uashed with toluene.
A uhite solid consisting of 5-~2'-chloro-4'-(tri-
fluoromethyl)phenoxy~-2-nitro-N-methanesulphonyl benzamide
~14.7 9; 0.034 mol; yield 67X), of the formula (VI), m.p.
198C, is thus obtained. The structure of this product
is confirmed by infrared and by NMR.
Example 3:
5-t2'-Chloro-4'-(trifluoromethyl)phenoxy]-2-nitro-
benzoic acid chloride (7.6 9; 0.02 mol) and methanesul-
phonamide (1.9 9; 0.02 mol) are dissolved ;n a mi~ture of
P(O)Cl3 (2 cc) and acetonitrile (20 cc). The reaction
m;xture ;s boiled under reflux for 2 hours 30 minutes
~;th st;rr;ng, and ;s then concentrated to dryness. The
crude mater;al obta;ned ;s rccrystallised from a mixture
of toluene and ethyl acetate (95/5).
A uh;te sol;d consist;ng of 5-C2'-chloro-4'-(tri-
fluoromethyl)phenoxy~-2-nitro-N-methanesulphonyl benz-
amide (7.6 9; 0.0173 mol; yield 87X), of the formula (VI),m.p. 215C, is thus obtained. The structure of this
product ;s confirmed by infrared and by NMR.

;lZ3~)S93
ExampLe 4:
5-C2'-Chloro-4'-(trifluoromethyl)phenoxy~-2-nitro-
benzoic acid t36.1 9; 0.1 mol) is suspended in a mixture
of toluene (60 cc) and dimethylformamide (DMF) (1 cc). The
reaction mixture is heated to 55C with stirring. A
solution of thionyl chloride (11.9 g; 0.1 mol) in toluene
(15 cc) is then added. When gas ceases to be evolved,
the reaction mixture is heated to 90C, before adding
methanesulphonamide (9.5 9; 0.1 moL). P(O)Cl3 (27 cc)
is then run in over a period of 10 minutes, and the reac-
tion mixture is then heated at 105C for 2 hours. Af-
ter cooling, the precipitate formed is filtered off and
then washed ~ith toluene.
A white solid consisting of 5-C2'-chloro-4'-(tri-
fluoromethyl)phenoxy]-2-nitro-N-methanesulphonyl benzamide
(23.8 9; 0.054 moL; yield 54%~, of the formula (VI), m.p.
200C is thus obtained. The structure of this product
is confirmed by infrared and by NMR.
Example 5:
This exampLe illustrates the preparation of benz-
amide of the formula (VI) starting from impure phenoxy-
benzoic acid. The purity of the starting phenoxybenzoic
acid was determined by high performance liquid phase
chromatography (abbreviated to HPLC); this HPLC was per-
formed under the following conditions:
- column 20 cm in Length, 4 mm in diameter,
- packing of silica on which a stationary phase contain-

123~593
1 ~,
ing an amine group has been grafted (the chromatographytakes pl-ace by a partit;on bet~een the stat;onary phase
and the eluant)
eluant: a mixture of 2,2,4-trimethylpentane, 2-propanol
and acet;c acid in constant volume proportions of 42/4û/18
respect;vely
- flow rate 2 cc/min.
The purity of the react;on product ~as also deter-
mined by HPLC under similar conditions except for varying
1û the proport;ons of the components of the eluant mixture
between the outset and the end of the chromatography,
from a ratio of 35/50/5 to 56/20/24 (elution gradient).
The accuracy of these chromatographic methods ~as
checked by the use of standards corresponding to the sam-
ples of each of the ;mpur;t;es mentioned, taken separateLy.
The percentages sho~n belo~ are percentages by~eight. The "technica ~grade" acid employed containS:
- 80.9% of 5-C2'-chLoro-4'-(trifluoromethyl)phenoxy]-2-
nitrobenzoic acid of the formula (V),
- 8.2X of 3-C2'-chloro-4'-(trifluoromethyl)phenoxy]-2-
nitrobenzoic acid,
- ~.3% of 5-C2'-chloro-4'-(trifluoromethyl)phenoxy]-4-
nitrobenzoic acid,
- less than 1X of 5-C2'-chloro-5'-(trifluoromethyl)phenoxy~-
2-nitrobenzoic acid, and
- less than 1Z of 3-C2'-chloro-4'-(trifluoromethyl)phenoxy~
benzoic acid.
.

1230593
- 15 -
Techn;cal-grade ac;d (38 9) of the composition
specified above is suspended in a mixture of 1,2-dichloro-
ethane (1ûO cc), thionyl chloride (10.3 cc; 0.109 mol) and
dimethyl~ormamide (1 cc). The reaction mixture is heated grad-
ually with stirring to the boil under reflux. Refluxing is con-
tinued for 1 hour after gas evolution has ended, and the
material is then concentrated to dr~ness. The residue
(4û 9) is dissolved in toluene (75 cc)~ after ~hich methane-
sulphonamide (10 9; 0.105 mol) and R(O)Cl3 (25 cc) are
added. The reaction mixture is then heated to the boil
under reflux for 3 hours ~ith stirring. After cooling,
the precipitate formed is filtered off and then ~ashed
w;th toluene.
A ~hite solid consisting of 5-~2'-chloro-4'-(tri-
fluoromethyl)phenoxy~-2-nitro-N-methanesulphonyl benzamide
(28 9) of the formula (VI), m.p. 200C, is thus ob-
tained. The structure of this product is confirmed by
infrared and by NMR. Its purity, as determined by HPLC,
is 90%.

gL23~593
- 15a -
SfJPI'l,E~ 'rARY DISCLOSU~E
~ he ~ollowing Example 111UGtrate3 the proce3s Or the
pre~ent in~ention in which, ln general formulae ~I~ and ~II),
t3 hydrog~n, B is chlorine, C 13 hydrosen, D is
trl~l~oromethyl, 3 ~ hydrogen, W ~g a -C~)= grou~, X in
general formula ~II) 19 chlorine, and R3 ln ~ormulae tI) and
~ 3 ~ethyl. The halogenating agent i3 ph~8phO
chlorlde.
Exam~le 6
5-~2'-Chlbro-4'-(tri~luoromethyl~phenoxy]-benzo1c
acid chlor~de ~8,4gS 0.025 mole) o~ the formul~:
Cl CCCl
~ ~/
, ~ethane~ulphonamlde ~2. 4g; 0 . 02S mole) and phosphar~ll
chlor~de ~12c~ were a~ded to a 5ac~ reactor wi~h he~tlng and
stir~lng. T~ reactlon mlxtu~e was heated for 1 hour at 90C
and then cooledS toluene ~Occ) and then petroleum ether
~3~cc) wera ad2~d. ~ho mlxtu~e thu~ oo~alned was ~iltered,
washed with p2troleum ether a~d dried to o~taln
5-~'-chloro-4l-~trlfluoromethyl)phenoxy~ methar~esulphon~l
benzamlde (~.7g: yield 8g~: melting point about 163C) o. the
ormula:
Cl ~ Co~ o2-c.i3
C~3 ~ ~ ~
. ~