Note: Descriptions are shown in the official language in which they were submitted.
10~63~33
The present invention relates to certain novel 2-
chloro-3,5-diiodo pyridine derivatives and to processes
for their preparation. The novel compounds possess
interesting herbicidal activity.
According to one feature of the present invention
there are provided compounds of the formula:-
OR
I ~ I (I)
~ Cl
wherein R represents a hydrogen atom, one equivalent of
an inorganic or organic cation or the group -OC-Rl or
-OC-ORl, (in which Rl represents an alkyl group with up
to 17 carbon atoms optionally substituted by halogen, an
alkenyl group with up to 4 carbon atoms, a cycloalkyl group
with 3 to 6 carbon atoms, a phenyl group optionally chloro-,
nitro- or methyl-substituted or a benzyl or styryl group),
the group -OC-NR2R3 (in which R2 and R3, which may be the
: same or different, each represent an alkyl group with 1 to
; 4 carbon atoms), or the group -02S-R4 (in which R4
represents an alkyl group with 1 to 4 carbon atoms or a
phenyl group optionally substituted by methyl).
Where R in formula I represents one equivalent of an
l~fi3~33
inorganic or organic cation the cations of alkali metal
and alkaline earth metal cations are preferred inorganic
cations whilst alkylammonium cations, for example those
derived from methylamines, ethylamines, ethanolamine and
piperidine are preferred organic cations.
Preferred compounds of formula I, by virtue of their
especially interesting herbicidal activity, are those in
which R represents the groups -OC-Rl and -OC-ORl, wherein
Rl represents a lower up to middle alkyl group, especially
an alkyl group with up to 3 carbon atoms, optionally
substituted by halogen. Halogen substituents in the groups
-OC-Rl and -OC-ORl are preferably chlorine or bromine atoms.
An especially preferred compound of the present
invention, by virtue of its particularly interesting
herbicidal activity, is 2-chloro-3,5-diiodo-4-acetoxy
; pyridine.
The present invention also relates to the compounds of
formula I together with at least one of:
ta) 3-(4-chlorophenyl)-1-methyl-1-(1-methyl-prop-2-ynyl)-
urea;
(b) 3-(4-chlorophenyl)-1-methyl-1-methoxyurea;
(c) 3-(3-chloro-4-methoxyphenyl)-1,1-dimethylurea;
I
109~3~3
(d) 3-(3-chloro-4-methylphenyl)-l,l-dimethylurea;
(e) l-benzthiazole-2-yl-1,3-dimethylurea;
(f) 3-(4-isopropylphenyl)-1,1-dimethylurea;
(g) 6-t-butyl-4-(2-methyl-propylideneimino)-3-methyl-
S mercapto-4,5-dihydro-1,2,4-triazlne-5-one;
(h) isobutyl-2-[4-(4-chlorophenoxy)-phenoxy]-propionate;
(i) ethyl-2-(N-benzoyl-3,4-dichloroanilino)-propionate;
:~ (j) l,l-dimethyl-3,5-diphenylpyrazolium-methosulfate;.
(k) 2-chloro-3-(4-chlorophenyl)-methylpropionate;
(1) methyl-2-[4-(2,4-dichlorophenoxy)-phenoxy]-propionate;
(m) a mixture of 4-chloro-2-methylphenoxy acetic acid and
9-hydroxyfluorene-9-carboxylic acid and the salts
thereof;
(n) 2-(4-chloro-2-methylphenoxy)-propionic acid and the
salts thereof;
(o) 2-(2,4-dichlorophenoxy)-propionic acid and the salts
thereof;
(p) a mixture of 2,4-dichlorophenoxy acetic acid and 4-
chloro-2-methylphenoxy acetic acid and the salts
thereof;
(q) 4-hydroxy-3,5-diiodobenzonitrile;
(r) 4-hydroxy-3,5-dibromobenzonitrile;
~ 38~
(s) 3-isopropyl-2,1,3-benzothiadiazinone-(4)-2,2-dioxide;
(t) 3,5-dibromo-4-hydroxybenzaldehyde-2,4-dinitrophenyl-
oxime;
(u) 2-(1-methyl-n-propyl)-4,6-dinitrophenylacetate; and
S (v) 4,6-dinitro-2-t-butylphenol.
Thus for example the invention includes, in combination,
(i) a compound of formula I as hereinbefore defined, and
(ii) a Mixture of the dimethylamine salt of 4-chloro-2-
methylphenoxy acetic acid and the dimethylamine salt of
9-hydroxyfluorene-9-carboxylic acid. The present invention
also includes, in combination (i) a compound of formula I
as hereinbefore defined, and (ii) a mixture of 2,4-di-
chlorophenoxy acetic acid and 4-chloro-2-methylphenoxy
acetic acid (in salt form).
According to a further feature of the present invention
there is provided a process for the preparation of compounds
of formula I as hereinbefore defined (wherein R represents
a hydrogen atom or one equlvalent of an inorganic or organic
cation) which comprises iodinating 2-chloro-4-hydroxypyridine
whereby 2-chloro-3,5-diiodo-4-hydroxypyridine is obtained
and, if desired, converting the said 2-chloro-3,5-diiodo-4-
hydroxypyridine into a compound of formula I in which R
1~963~3
represents an equivalent of an inorganic or organic cation.
The iodination may, for example, be effected by the use
of iodine(I)-chloride or iodic acid/iodine. When using
iodine(I)-chloride the reaction is preferably effected in
the presence of acetic acid, aqueous hydrochloric acid or
water, conveniently at an elevated temperature, for example
!' at the boiling temperature of the reaction mixture. When
the iodination is effected by the use of iodic acid/iodine,
the iodination is preferably effected in the presence of
water/ethanol. Other organic solvents miscible with water
may conveniently be used instead of ethanol, if they are
sufficiently inert under the reaction conditions, for
example acetic acid.
The compounds of formula I wherein R represents a
hydrogen atom or an equivalent of an inorganic or organic
cation may, if desired, be employed as starting materials
in the preparation of the remaining compounds of formula I.
Thus according to a further feature of the present
invention there is provided a process for the preparation of
compounds of formula I as hereinbefore defined (wherein R
represents the group -OC-Rl, -OC-ORl, -OC-NR2R3 or -O2S-R4
in which Rl, R2, R3 and R4 are as hereinbefore defined)
-- 6 --
- . . 1
1~9~3~3
- which comprises reacting 2-chloro-3,5-diiodo-4-hydroxy-
pyridine with a compound of the formula:-
Rl-C0-X (II); R10-C0-X (III); R2R3N-C0-X (IV); or
4 S 2 X (V)
(wherein Rl, R2, R3 and R4 are as hereinbefore defined and
X represents an atom or group removable as an anion)
; whereby a compound of formula I as hereinbefore defined
J (wherein R represents the group Rl-C0-, R10-C0-, R2R3N-C0-
or R4-S02- in which Rl, R2, R3 and R4 are as hereinbefore
defined) is obtained.
A compound of the formula II, III, IV or V is
preferably used in which X represents a chlorine or bromine
atom.
-` Where it is desired to prepare a compound of formula I
in which R represents the group -OC-Rl, a compound of
formula II may conveniently be used in which X represents
the group -0-OC-Rl (in which Rl is as hereinbefore defined).
Thus the acylation may be effected by the use of an acid
anhydride of formula Rl-C0-0-OC-Rl.
The compounds according to the present invention
possess herbicidal activity. Furthermore the compounds of
formula I, wherein R represents a hydrogen atom or one
-- 7 --
-
1~963~13
equivalent of an inorganic or organic cation, may be used
as intermediates in the production of herbicides.
According to a further feature of the present invention
there are provided herbicidal compositions which comprise
as active ingredient at least one compound of formula I as
hereinbefore defined in association with an inert carrier or
diluent.
The compositions preferably comprise 2-chloro-3,5-
diiodo-4-acetoxypyridine as active ingredient.
The compounds of the present invention are herbicidally
active using leaf or soil treatment. At high dosages the
compounds of the invention may serve as total herbicides,
whereas at lower dosages (<0.25 kg/ha) the compounds of the
present invention may be used to selectively kill broad-
leaf weeds, for example in cereal fields by means of post-
emergence leaf-treatment.
The compositions of the present invention may, for
example, be in the form of wettable powders, dusting powders,
granulates, solutions, emulsifiable concentrates, emulsions
or sprays. The active ingredient content of the compositions
of the present invention may amount to about 90% by weight.
Compositions suitable for use without dilution
-- 8 --
1~9~i;3~3~
,
preferably contain from 0.001 to 5% by weight, preferably
0.005 to 1% by weight. Dusting agents and, especially, ULV
: (ultra low volume) formulations may contain higher concen-
trations of active ingedient, for example, up to
approximately 85% by weight.
The herbicidal compositions of the present invention
may be formulated in conventional manner, at least one
active ingredient of formula I being mixed with conventional
carriers or excipients for example solvents, diluents,
wetting and adhesive agents, emulsifiers and dispersants,
optionally together with other herbicides or biocides.
The superior activity of the compounds according to
the invention is shown, for example, by the following
comparative test (greenhouse test, leaf treatment):-
A: 2-chloro-3,5-diiodo-4-acetoxypyridine (according to
invention)
B: 2-chloro-3,5-diiodo-4-acetoxy-6-methylpyridine (U.S.
Patent 3,859,295)
In order to achieve 90% extermination of broad-leef weeds
0.043 kg/ha of A and 0.29 kg/ha of B are required.
Tests which we have conducted show that the active
_ g _
,'
~91~38~
;,
ingredient according to the invention, especially 2-chloro-
3,5-diiodo-4-acetoxypyridine, may be used with advantage in
combination with other herbicides Thus in one embodiment
of the present invention the herbicidal compositions
additionally contain as a further active ingredient at least
one of the following:-
(a) 3-(4-chlorophenyl)-1-methyl-1-(1-methyl-prop-2-ynyl)-
urea;
(b) 3-(4-chlorophenyl)-1-methyl-1-methoxyurea;
(c) 3-(3-chloro-4-methoxyphenyl)-1,1-dimethylurea;
(d) 3-(3-chloro-4-methylphenyl)-1,1-dimethylurea;
(e) l-benzthiazole-2-yl-1,3-dimethylurea;
(f) 3_(4-isopropylphenyl)-1,1-dimethylurea;
(g) 6-tert.-butyl-4-(2-methyl-propylideneimino)-3-methyl-
mercapto-4,5-dihydro-1,2,4-triazine-5-one;
(h) isobutyl-2-[4-(4-chlorophenoxy)-phenoxy]-propionate;
(i) ethyl-2-(N-benzoyl-3,4-dichloroanilino)-propionate;
(j) 1,1-dimethyl-3,5-diphenylpyrazolium-methosulfate;
(k) 2-chloro-3-(4-chlorophenyl)-methylpropionate;
(1) methyl-2-[4-(2,4-dichlorophenoxy)-phenoxy]-propionate;
(m) a mixture of 4-chloro-2-methylphenoxy acetic acid and
9-hydroxyfluorene-9-carboxylic acid and the salts
- 10 -
1~)63~33
thereof;
(n) 2-(4-chloro-2-methylphenoxy)-propionic acid and the
salts thereof;
(o) 2-(2,4-dichlorophenoxy)-propionic acid and the salts
. .
; 5 thereof;
(p) a mixture of 2,4-dichlorophenoxy acetic acid and 4-
chloro-2-methylphenoxy acetic acid and the salts thereof;
(q) 4-hydroxy-3,5-diiodobenzonitrile;
(r) 4-hydroxy-3,5-dibromobenzonitrile;
(s) 3-isopropyl-2,1,3-benzothiadiazinone-(4)-2,2-dioxlde;
(t) 3,5-dibromo-4-hydroxybenzaldehyde-2,4-dinitrophenyloxime;
(u) 2-(1-methyl-n-propyl)-4,6-dinitrophenylacetate; and
(v) 4,6-dinitro-2-t-butylphenol.
In one embodiment of the present invention the further
active ingredient comprises a mixture of the dimethylamine
salts of 4-chloro-2-methylphenoxy acetic acid and 9-hydroxy-
fluorene-9-carboxylic acid. In a further embodiment of the
present invention the further active ingredient comprises a
mixture of 2,4-dichlorophenoxy acetic acid and 4-chloro-2-
methylphenoxy acetic acid in salt form.
We have found that a more favourable spectrum of
activities or a synergistic effect may be achieved by the
~`~963~33
use of such combinations. In such combinations the active
- ingredient according to the invention, in particular the
above-mentioned especially preferred compound, is
advantageously used in a concentration of approximately 0.03
to 1.0, preferably 0.05 to 0.3 kg/ha. Each of the effective
ingredients is conveniently used in from 50 to 100% of the
normal dose. In typical combinations of the above-mentioned
type, the following quantities of active ingredient may for
example be used, together with from 0.05 - 0.2 kg/ha of
2-chloro-3,5-diiodo-4-acetoxypyridine and, for example, from
0.1 to 6.0 kg/ha of the further active ingredient preferably
about:
; 1.0 kg/ha 3-(4-chlorophenyl)-1-methyl-1-(1-methyl-prop-2-
ynyl)-urea,
0.5 kg/ha 3-(4-chlorophenyl)-1-methyl-1-methoxyurea,
3.3 kg/ha 3-(3-chloro-4-methoxyphenyl)-1,1-dimethylurea,
2.0 kg/ha 3-(3-chloro-4-methylphenyl)-1,1-dimethylurea,
2.5 kg/ha 1-benzothiazole-2-yl-1,3-dimethylurea,
1.5 kg/ha 3-(4-isopropylphenyl)-1,1-dimethylurea,
0.9 kg/ha 6-t-butyl-4-(2-methyl-propylideneimino)-3-
methylmercapto-4,5-dihydro-1,2,4-triazine-5-one,
: 0 9 kg/ha isobutyl-2-[4-chlorophenoxy)-phenoxy]-propionate,
- 12 -
1~9~,383
1.6 kg/ha ethyl-2-(N-benzoyl-3,4-dichloroanilino)-
propionate,
1.0 kg/ha 1,1-dimethyl-3,5-diphenylpyrazolium-methosulfate,
4.0 kg/ha 2-chloro-3-(4-chlorophenyl)-methylpropionate,
1.0 kg/ha methyl-2-[4-(2,4-dichlorophenoxy)-phenoxy]-
propionate,
1.0 kg/ha a mixture of the dimethylamine salts of 4-chloro-
2-methylphenoxy acetic acid (760 g) and 9-hydroxy-
fluorene-9-carboxylic acid (240 g),
2.4 kg/ha 2-(4-chloro-2-methylphenoxy)-propionic acid and
the salts thereof,
2.4 kg/ha 2-(2,4-dichlorophenoxy)-propionic acid and the
salts thereof,
0.8 kg/ha a 1:1 combination of 2,4-dichlorophenoxy acetic
acid and 4-chloro-2-methylphenoxy acetic acid
(as salts),
0 4 kg/ha 4-hydroxy-3,5-diiodobenzonitrile,
0 4 kg/ha 4-hydroxy-3,5-dibromobenzoinitrile,
2.0 kg/ha 3-isopropyl-2,1,3-benzothiadiazinone-(4)-2,2-
dioxide,
2.0 kg/ha 3,5-dibromo-4-hydroxybenzaldehyde-2,4~dinitro-
phenyloxime,
6383
2.5 kg/ha 2-(1-methyl-n-propyl)-4,6-dinitrophenylacetate, or
3.0 kg/ha 4,6-dinitro-2-t-butylphenol.
The preceding further active ingredients may, however,
be used in varying doses. Thus, for example, the
quantity of those herbicides which act primarily upon
monocotyledons may be reduced to approximately 75% and
the quantities of the other herbicides to approximately
50% of the quantities indicated above. If required,
the quantity of the active ingredient according to
the present invention employed in compositions comprising a
further active ingredient may be increased, preferably within
the range indicated above, at the same time as the quantity
of further active ingredient is reduced. If desired, the
further active ingredients listed above may be applied in a
lS concentration increased by approximately 50% over that
indicated in the list, in which case the active ingredients
according to the present invention will be applied in a
lower concentration than the range indicated above.
According to a still further feature of the present
invention there is provided a method for controlling
undesired vegetation which comprises applying to the locus
of said undesired vegetation an effective amount of a
composition as hereinbefore defined.
- 14 -
1~963~13
The following Examples illustrate the present invention:-
EXAMPLE 1
2-Chloro-3,5-diiodo-4-hydroxypyridine
- 129.5 g (1 mol) of 2-chloro-4-hydroxypyridine and
203.2 g (0.8 mol) of iodine are added to 1 ltr. of ethanol
and heated while stirring. -At 60 to 70C, a solution of
70.4 g (0.4 mol) of iodic acid dissolved in 200 ml of
water is added dropwise to the reaction mixture. The
reaction mixture is then refluxed for 30 minutes, allowed
to cool and the crystals thus formed are filtered off with
suction. The crystals are then rinsed with cold ethanol
and dried at 100-110C.
! The yield is 366 g (96% of theory).
The substance decomposes at >290C.
EXAMPLE 2
2-Chloro-3,5-diiodo-4-acetoxypyridine
191 g (0.5 mol) of 2-chloro-3,5-diiodo-4-hydroxypyridine
are suspended in 400 ml of acetic anhydride and refluxed for
30 minutes. A clear solution is obtained which is stirred
after cooling into 5 ltr. of water. The precipitating
solid is filtered off with suction, washed with water and
dried at 50-60C. The yield amounts to 192 g (91% of theory);
- 15 -
~9G3~3
m.p. 127-128C (from ethanol).
EXAMPLE 3
2-Chloro-3,5 diiodo-4-hydroxypyridine sodium salt
381.5 g (1 mol) of 2-chloro-3,5-diiodo-4-hydroxy-
pyridine are added to a solution of 23 g (1 mol) of sodium
in 200 ml of methanol. The methanol is completely distilled
off from the solution obtained, under the current addition
of toluene whereby a colourless powder precipitates, which
is filtered off with suction and dried. The yield is
quantitative.
EXAMPLE 4
2-Chloro-3,5-diiodo-4-methoxycarbonyloxypyridine
38.1 g (0.1 mol) of 2-chloro-3,5-diiodo-4-hydroxy-
pyridine, 15 g (0.15 mol) of methyl chloroformate and 27.6 g
(0.2 mol) of potassium carbonate are refluxed for 3 hours
in 300 ml of acetonitrile. After cooling, the reaction
mixture is poured onto water, extracted with methylene
chloride, the organic phase is shaken with 1% sodium
hydroxide solution and water, dried over sodium sulfate and
evaporated The remaining oil solidifies when cooling to
form a crystal cake, which may be recrystallized from cyclo-
hexane Yield: 35 g(82.7% of theory); m.p 74-75C,
- 16 -
1~9~;3~3
EXAMPLE 5
-
2-Chloro-3,5-diiodo-4-(N,N-dimethylcarbamoyloxy)-pyridine
8.1 g (0.02 mol) of the sodium salt of Example 2 are
boiled while stirring with 4 2 g (0.04 mol) of dimethyl-
carbamoyl chloride in 50 ml of toluene for 20 hours. The
residue is then filtered off, the cooled solution is shaken
with 0.5 N sodium hydroxide solution and water and evaporated.
When triturated, the remaining oil solidifies and is
crystallized from ethyl acetate. Yield: 6 g (64% of theory);
m.p. 148-149~C.
EXAMPLE 6
(a) 129.5 g (1 mol) of 2-chloro-4-hydroxypyridine and
203.2 g (0.8 mol) of iodine are suspended in a mixture of
1.6 ltr. of ethanol and 400 ml of 20% sulfuric acid, while
stirring. The mixture is heated to 60~C and over a period
of 30 minutes a solution of 86 g of potassium iodate in 200
ml of water is added dropwise to the mixture. The reaction
mixture is refluxed for a further 30 minutes, allowed to
cool and the suspension is then decolorized by the dropwise
addition of 20 mls of a saturated solution of sodium hydrogen
sulfite in water. The reaction mixture is then filtered off
with suction, washed thoroughly with water and rinsed with
- 17 -
1~9~ 3
a little cold ethanol. After drying at approximately 100C,
340 g (89% of theory) of Z-chloro-3,5-diiodo-4-hydroxy-
pyridine are obtained.
(b) 129.5 g (1 mol) of 2-chloro-4-hydroxypyridine are
suspended in 4 ltr. of 10% hydrochloric acid. A solution of
324 g (2 mol) of iodine chloride in 650 ml of 10% hydro-
chloric acid is poured into the mixture while stirring and
is slowly heated to boiling. The reaction mixture is allowed
to cool, the separated product is filtered off with suction,
washed thoroughly with water and dried at 110C. The yield
of 2-chloro-3,5-diiodo-4-hydroxypyridine amounts to 320 g
(84% of theory).
(c) 253 g (1 mol) of iodine are suspended in 1 ltr. of
acetic acid. At room temperature 71 g of chlorine gas are
introduced into the mixture in the course of one hour. To
the solution thus obtained are added 129.5 g (1 mol) of
2-chloro-4-hydroxypyridine and the mixture is heated for 30
minutes to 100C. The mixture is then cooled, poured onto
3 ltr. of water, filtered off with suction, washed thoroughly
with water and dried at 110C. The yield of 2-chloro-3,5-
` diiodo-4-hydroxypyridine amounts to 340 g (89% of theory).
(d) a mixture of 129.5 g (1 mol) of 2-chloro-4-hydroxy-
- 18 -
1~ 9G~3~ 3
pyridine and 253 g (1 mol) of iodine is suspended in 1 ltr.
of acetic acid and heated to 60C while stirring. A mixture
- of 30 ml of nitric acid (d 1.4) and 110 ml of sulfuric acid
; (d 1;84) is added dropwise to the suspension and subsequently
the temperature is maintained at 60C for 30 more minutes.
The reaction mixture thus obtained is then poured onto 3 ltr.
of water, filtered off with suction, washed thoroughly with
water and dried at 110C. The yield of 2-chloro-3,5-diiodo-
4-hydroxypyridine amounts to 335 g (88% of theory).
Corresponding to the preceding Examples, the compounds
of the following table may also be obtained.
- 19 -
` - ~
1~96383
Example No. R [8Cl] ing Point
,. , , . .-
n-C 3H7-C0- 58-60
8 CH3-CH-CH2-C0- 55-56
. CH3
9 n C7H15 C0 oil
17H35 C0 61-63
11 CH3-CH=CH-C0 113-114
12 Cl-CH2-CH2-C0 99-100
13 CH3-CH-C0- 98-100
Br
: C12CH-CO- 99-100
~ C0- 93-95
16 O - C0- 93-94
17 ~ C0- 149-151
:.:
18 Cl ~ C0- 115-120
19 CH3 -~ C0- 158-159
.
- 20 -
..
~ 1~963~33
Example ~lc~in~ Point
¢3~ C0- 150-151
.. N02
21 ~ - C0 146-148
22 ~ - CH2-C- 119-120
23 <~3--CH=CH-Co_ 135-136
24 n C3 7 0 C0 58-59
CH3-CH-0-C0- 147-149
CH3
26 CH3 ( CH2) 12-14 C0 o ll
: ( mixture)
27 CH3( CH2 ) 3-CH-CH2-0-C0- oil
C2H5
28 (C2H5)2N-C0- 132-133
29 CH3-S02- 133
H3C ~ S2- 158
31 C 2H5 C0 146-147
- 21 -
,. .1
~96383
In the following Examples all percentages are by weight.
Herbicidal composition Examples
EXAMPLE A
Wettable Powder
25% of 2-chloro-3,5-diiodo-4-acetoxypyridine
55% of kaolin
10% of colloidal silicic acid
9% of lignine sulfonate (dispersing agent)
1% of sodium tetrapropylene benzosulfonate (wetting agent)
EXAMPLE B
Wettable Powder
80% of active ingredient according to the invention
8% of calcium lignine sulfonate
5% of colloidal silicic acid
5% of sodium sulfate
2% of diisobutyl-naphthalene sodium sulfonate
EXAMPLE C
Emulsifiable Concentrate
40% of active ingredient according to the invention
25% of Shellsol A (liquid mixture of aromatic hydrocarbons)
25% of N-methylpyrrolidone
10% of Emulsogen I 40 (anion-active emulsifier)
- 22 -
1~9~;3133
The concentrates indicated above are diluted to the
desired concentration of active ingredient for use with
water (0.001 to 5% by weight).
- 23 -
