Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
3L~3S~3~
This invention relates to novel selective herbicides
for the control of wild oatS in cereal crops.
U.K~ specification 1,164,160 describes and claims a
class of selectively herbîcidal compounds of formula:
(R)n ~ N / COR" (I)
R'Y
wherein R represents a halogen atom or an alkyl or alkoxy
group; n is O or an integer from 1-5 and when n is
greater than 1 each R group may be the Same or different;
Rl represents an alkylene group; R~ representS an alkyl,
alkoxy, aryl, or an aryloxyalkylene group; and Y represents
a carboxy group or salts or esters thereof or a carbamoyl
group optionally mono- or di-N-substituted.
Although the compounds known from U.K. specif;cation
No. 1,164,160 have shown good selectively herbicidal
properties when used to combat wild oats in wheat crops
they have proved less reliable for use in barley due to
their tendency to produce phytotoxic symptoms in the crop
as well as in the wild oats.
It has now been found that a group of closely related
compounds have interesting selectivity properties for the
control of wild oats in cereal crops, especially barley.
Accordingly the invention provides novel compounds
having the following general formula:
1~5~3~i
(R)n ~ C0(~6H5 (II)
CI'H - COOY
CH3
wherein R is chlorine, bromine and/or fluorine; n is
l, 2, 3, or 4~ and Y is an alkyl or alkenyl group
containing l to lO carbon atoms and bearing at lea~st one
fluorine, chlorine and10r bromine atoms.
Compounds giving the best results have n equal to
l or 2 when R is chlorine and/or fluorine, fo~ example,
those compounds having (R)n representing a ~-chloro-,
4-chloro , 3-fluoro-, 4-fluoro-, 3,4-dichloro-,
3,4-difluoro-, 3-chloro-4-fluoro-, or 3-fluoro-4~chloro~
substitution. Particularly effective are the compounds
; with a 4-halogen-substitution or a 3,4-di-halogen-
substitution.
As regards Y, the alXyl or alkenyl group may be
straight or branched chain and preferably contains
l to 6, especially l to 3, carbon atoms. The compounds
according to the invention are characterized by the
presence of at least one ~luorine, chlorine and/or
bromine atoms in the alkyl group Y and, generally
; 20 speaking9 the presence of one, two or three of such
halogen atoms gives rise to satisfactory herbicidal
activity. The group 2~chloroethyl- is especially
effective.
~s~
The compounds accordin~ to the invention may be
prepared by a process which comprises reactin~ an
acid of formula:
(R)n ~ COC~H5 (III)
CHCOOH
IH3
with the appropriate halogenated alcohol. This
esterification reaction may be carried out in the
presence of a suitable esterification catalyst, e.g.
an inorganic acid such as sulphuric acid or an organic
acid such as p-toluene-sulphonic acid. The acid (III)
may be prepared by a number of routes a convenient
example being the benzoylation of the appropriate amino-
acid ester followed by a hydrolysis step to liberate the
free acid.
Particular examples of the compounds according to
the invention which have useful selective activity against
wild oats in cereal crops are:
2-chloroethyl N benzoyl-N-(394~dichlorophenyl)-
2-aminopropionate
2-chloroethyl N-benzoyl N-(4-fluorophenyl)-
2-aminopropionate
2-chloroethyl N-benzoyl-N-(3-chloro-4-fluoro-
phenyl)-2-aminopropionate .
5;~3~t;
The compounds may be used in the manner known for
herbicides and the invention includes therefore herbicidal
compositions comprising a carrier or a surface-active
agent, or both a carrier and a surface-active agent
together with, as active ingredient a compound of the
invention. Likewise the invention includes also a method
of combating the growth of wild oats in cereal crops at
a locus which comprises applying to the locus a selectively
herbicidal amount of a compound or a composition of the
invention.
The term "selectively herbicidal amount1' as used
herein denotes an amount of the compound or composition
sufficient to produce a substantial reduction on the
growth of wild oats while at the same time producing an
insignificant phytotoxic effect on the crop. The
selectively herbicidal properties of the compound are
illustrated in the Examples below.
The term "carrier" as used herein means a solid or
fluid material, which may be inorganic or organic and of
synthetic or natural origin, with which the active
compound is mixed or formu~ated to facilitate its
application to the plant, seed, soil or other object to
be treated, or its storage, transport or handling.
The surface-active agent may be an emulsifying
agent or a dispersing agent or a wetting agent; it may
be nonionic or ionic.
~3S'~3~3
-- 6 --
Any of the carrier materials or surface-active
agents usually applied in formulating pesticides may
be used in the compositions of the invention, and
suitably examples of these are to be found, for
example, in our U.K. specification No. 1~289,283
or 1,164,160.
The compositions of the invention may be
formulated as wettable powders, dusts, granules,
solutions, emulsifiable concentrates, emulsions,
suspension concentrates and aerosols. Wettable powders
are usually compounded to contain 25, 50 or 75% w of
toxicant and usually contain, in addition to solid
carrier 3-10% w o~ a dispersing agent and~ where neces-
sary, 0-10% w of stabilizer(s) and/or other additives
such as penetrants or stickers. Dusts are usually
formulated as a dust concentrate having a similar
composition to that of a wettable powder but without
a dispersant, and are diluted in the field with further
solid carrier to give a composikion usually containing
0.5-10% w of toxicant. Granules are usually prepared
to have a size between lO and 100 as mesh (1.676 -
0.152 mm), and may be manufactured by agglomeration or
impregnation techniques. ~enerally, granules will
contain 0.5-25% w of toxicant and 0-10% w of additives
such as stabilizers, slow release modifiers and binding
agents. Emulsifiable concentrates usually contain, in
addikion to the solvent and when necessary, co-solvent,
~s~
- 7 -
10-50% wtv toxicant, 2-20% w/v emulsifiers and 0.20% w/v
o~ appropriate additives such as stabilizers, penetrants
and corrosion inhibitors.
Suspension concentrates are compounded 90 as to
obtain a stable, non-sedimenting, flowable product and
usually contain 10-75% w toxicant~ 0.5-15% w of dispers-
ing agents, 0.1-10% w of suspending agents such as
protective colloids and thixotropic agents, 0-10% w of
appropriate additives such as defoamers, corrosion
inhibitors, stab;lizers, penetrants and stickers, and
as carrier, water or an organic li~uid in which the
toxicant is substantially insoluble, certain organic
solids or inorganic salts may be dissolved in the
carrier to assist in preventing sedimentation or as
antifreeze agents for water.
Aqueous dispersions and emulsions, for example,
compositions obtained by diluting a wettable powder or
a concentrate according to the invenkion with water,
also lie within the scope of the present invention.
The said emulsions may be of the water-in-oil or of the
oil-in-water type~ and may have a thick "mayonnaise"-
like consistency.
The compositions of the invention may also contain
other ingredients, for example, other compounds
possessing pesticidal, especially insecticidal, acaricidal,
herbicidal and fungicidal properties.
XAMPLE 1 Pre~aration of 2-chloroethyl N- _nzoyl-N-
(3-chloro-4-fluorophenyl)-2-aminopropionate
N-Benzoyl-N-(3-chloro-4~fluorophenyl)-2-amino-
propionic acid (3.215 g, 0.01 mole) was dissolved in
2-chloroethanol ~25 ml) and dry hydrogen chloride was
passed through the stirred solution for 6 h~ The
mixture was heated at 100C for 3 h and the solvents
were evaporated. The residue was dissolved in ether
(100 ml) and the ether was washed with sodium ~i-
carbonate solution and water. The ether layer wasseparated, dried (Na2S0l~) and evaporated to give an
oil which gave on treatment with hexane white crystals
(3.1 g, 80%), m.p. 78-80C, of ~ -N-benzoyl-
N-(3-chIoro-4-fluoro~heny])-?-aminopropionate.
~Found: C 56.2; H 4.2; N 3.6. C18H16C12FNO3 requires
C 56.3; H 4.2; N 3.6~.)
EXAMPLES 2 - 15
A series of compounds were prepared employing the
same process as given for the compound of Example 1,
Details of the compounds and their physical properties
are given in the table below:
R1 ~ COC6H5 ~IV)
~ CHCOOY
R2 CH3
3~
, . . ~
__ _ _ . _ _ a~ L~ L~ ~1 _ _ . _
Z; . .. . . . . . . . . o ~ ~ ~
____.... .___ _ _ . _ . _ ~ r~
oo J ~ o 1 o~ o o t~l ~ ~r r~ c-
=r ~r u~ ~ ~ 3 ~r ~ ~ ~r ~
_ ___ _____ _...... _... ~ .~ ....... .____.__ .
~ o ~ ~ ~ o ~ ~ o ~ ~ =r ~D O t_
o~ o~ U~ L~ o o~ L~ Lr ~ ~ ~ ~ ~ L~
L~ Ln U~ U~ ~ L~ L~ Lr~ Li~ U~ L~ ~ L~
_ ....... __ _ _ _ __ _
~q ~ ~n ~q lQ ~ ~q
rl ~ ~ ~ ~ a) ~
~rl ~ . ~ r ~ ~r ~ ~r ~ h h ~ .
c~ ~ P~ ~ l~ p:; ~ p~ P~ 1~ p:; ~
~ ~ ~ ~ æ ..
O O r~ O O ~ O
N V V V V V V
~ 00 ~ ~D ~ J 00
:r~ ~ P:~ ~C~
~1 ~ OD 0
C~ V C~ C) C~ C~ V
__ .- _ : ._ _ ,.
O~ oV oV
~ ~D~ O ~3 ''01 ~ ''01 r~
-- _ _ _ N ~ _ r l
N V V V
rl V N I l V V
-1 5~ N N r l :1: V C.)
N _, N N N N _,
:c ~ m ~ ~c :r: ~
N _ _ r-l r l r l
~; ~ ~ m v v v v
. _ ____
~ ~ V ~ C~ ~ C~ C~
._ _ _ __ ~
~ cu r(~ ~ u\ ~:> e- OD
~3
_ ~ _
3~
- 10 -
_ __ ~ I~ CO N 15~ ~ Ir~ ~ N 3
~: ~ r~ 3 r~ ~ ~ t~ J ~ ~ ~ 1~ 1~ 1~
_ _ _ _
~ t~ ~ ~ ~ N ~-I ~1 J O J Ir~ C0
t~ =S =~r ~ =~ J , 1~ ~ ~ 3 ::r t~ ~\ 1~ 1
C~ o ~ co ~ ~ ~ Lr~ ~ oC) O L~ ~ ~ O
3 ~ ~1 N N C0 cr~ 1~ ~D t~ ~\1 ~ C)
Ir~ ~ ~D ~D ~D '`D Ir~ ~ 1~ J L~
_ . __ ___
tn ~o ~q oq c7 lQ U~ ~q
~rl ~ ~L) a~ a) a) (I)
,h ~ r~ J .r ~d h ~ r C S I ~d rl
1~ ~ ~ ~ ~ ~ ~ ~ ~ 1~ ~; ~ O
¢ ~ ~ P; ~ ~r ~ ~; ~ ~;
~ ~ l
~ 1~ O O ~\
:z; o~ æ z~ z;~ ~ o~
r~ Zr-l ¢l V r l r-l
O~ t~O~ L~ \~1:) J Lt~
~ ~ico 5~J ~ ~1 ~ ~
V~ V~V~ V~ V~ C~ ~
__ _ _ __
V V U O r-l V r~
J ~Lf ~ ~C) rl J rl
_e N __ _
r VN ~
r l ~ 11 N
V V VN ~ r-l 1~ r-l
~ ~ ~ ~ V ~ ~
N ~`J N N ~ N N
~ ~ V ~V V V ~V
__ _ ,_ _
N r l ~ ~ ~ r-l V r-l
_ _._ _ _ _ _
~;. r l ~1 114 ~4 ~1 ~ rv
_ __
r-l 0~ O ~1 N ~1 J ~rl
~1
_
EXA~PLE 16 Tests demonstratin~ selectivel~ herbicidal
~ barley)
25 seeds of barley (var. Imber~ or 30 seeds of wild
oats (Avena fatua) were planted in John Innes No. 1
compost contained in 7 cm pots. When the plants had
reached the 1~-2~ leaf stage the pots were sprayed with
a solution of the compound under test in a 1:1 acetone/
water mixture containing added wetter~sticker. Barley
plants were treated at dosages from 10 to o.6 kglha and
the wild oats at dosages from 2.0 I;o 0.15 kg/ha. Each
dosage was replicated four times. The pots were kept in
a glasshouse at ca 21C with 16 hours per day of light.
Assessments were made 10-14 days after spraying.
Barley was cut at soil level and the plant weight
expressed as a percentage of untreated barley weight.
The percentage depression in growth of the wild oats was
assessed visually. These figures were then used to
calculate the growth inhibitio~n dosages and the dosage
to give a 10% reduction in barley (GID1o) was compared
with that to give 90% reduction in wild oats (GIDgo)~
The selectivity factor for the compound is then given by
the expression:
1 0,
GIDgo wild oats
The results of this test are shown in the following
Table, in which the results for the closely related
- 12 ~
compound ethyl N-ben~oyl N-(3,4-dichlorophenyl)-
2-aminopropionate are included for comparison. This
compound is disclosed in U.K. 1,164,160.
TABLE
Rl ~3 COC6H5
CHCOOY
R2 CH3
_ _ __ _ _ _ _
Example ~ ¦R2 ompound GID1o GIDgo Selectivity
barley oat factor
. _ _ ~ _
6 C1 Cl CH2CH2Cl 6.49 4.1 1.6
1 F Cl CH2CH2Cl 0,44 0.60 0.73
F H CH2CH2Cl 1.02 1.98 0.51
: 11 F H CH2CH2CH2C ¦ 26.0 8.60 3.o
Comparlson Cl ~ ~ 5 _ 0.09 2 45 0.037
From these results it can clearly be seen that the
compounds according to the invention have a better
selectivity than the closely-related comparative compound.
