Note: Descriptions are shown in the official language in which they were submitted.
3~
The present invention rela-tes to compounds useful as
antidotes against the treatmen-t of plants with herbicides and
to -their use an-tidotes.
This application is a divisional applica-tion of copend-
ing~application No. ~23,89~ Eiled March :L8, 1983.
Ilerbicides belonging -to the class of chloroacetanilides
or of thiolcarbamates are very useful compounds agains-t the weeds
infes-ting agrarian cultivations.
Many of these herbicides, however, also exert their
10 toxic action towards cer-tain useful cul-tivations such as, for
example, maize and sorghum, and, in consequence, being non-
selective, -they cannot be used for weed-killing in such culitva-
tions.
The availabi:Lity of antidotes, i.e. oE compouncls whjc~l
pro-tect the usefu:L cultivations from the action of the herbicides
without contemporaneously reducing their herbicide action towards
the infes-ting plan-ts, also allows use of these herbicides
for defending those useful cultivations which otherwise would
be damaged.
Among the main herbicides which prove -to be phyto-
toxic for cer-tain useful cultivations -there are those belonying
to the class of the chloroace-tanilides comprising, for example,
N-methox~me-thyl-2, 6-die-thyl~chloroacetanilide tCommon name:
Alachlor). N-butoxymethyl-2, 6-die-thyl-chloroacetanylide
(common name: Butachlor), N-methoxyethyl-2-methyl-6-allyl-chloro-
acetanilide and the ones belonging to the class of the thiol-
carbama-tes comprising, e.g., N,N-diiaopropyl-S-(2, 3-dichloro-
allyl)-thiolcarbamate (common name: Dialla-te); N,N-diisopropyl-
S-(2,3,3-trichloroallyl)-thiolcarbamate (common name: Triallate);
N,N-diethyl-S-(4-chlorobenzyl)-thiolcarbamate (common name:
Benthiocarb); N,N-dipropyl-S-etllyl-thiolcarbamate (common name:
Eptam).
Compounds belonging to dif~erent chemical classes are
known which are capable of protecting useful cultivations from
the toxic action exerted by the herbicides.
For example, dichloroacetamides useful as antidotes
have been described in U.S. Patent NoO ~,021,22~ (Stauffer) or
in U.S. Paten-t No. ~,228,101 (Monteclison S~poA~ ) ~ 2-chloro-
thiazoles disubstituted in positions ~, 5, which are useful as
antidotes in the defence of sorghum cul-tivations have been
described in European Patent application No. 27019 (Monsanto Co.)O
-- 2
h~
~ pplicants have now found that the -toxic action
oE non-selec~ive herbicides, belonging e.g. to the class of the
chloroacetanilides and of the thiolcarbamates, towards useful
cultivations can be signiEicantly reduced or elimina-ted, without
decreasing, at the same time, the herbicide action towards in-
festing plants if use is made, as antido-tes, of compounds of
formula:
/ ____.
N - COOR (I)
~1
where:in: group COOR is in position 2 or ~ in the thiazolidine
ring, r~ represents a hydrogerl atom or an alkyl Cl-C4; Rl repre-
sents a hydrogen atom,or an acetyl group optionally subs-tituted by
1 to 3 halogen atoms.
~'~ h~C~/~
Thus, the inven-tion disclosed and claimed in copending~J
application No. 423,89~, is a method of reducing the damage~ to-
wards useful cultiva-tions caused by non-selec-tive herbicides
20 belonging, for example, to -the class of the chloroacetanilides
or of the thlolcarbamates, such method comprising treat:Lng the
seeds, the plants or the soll in which they grow with arl eEfec-
tive amount of an antido-te of formula I, ei-ther as such or in -the
form of a sui-table composi-tion.
The invention of the copending; application also discloses
and claims compositions containing a compound of formula I as an
ac-tive ingredien-t along with inert vehicles and optionally other
additives useful -to trea-t the seeds of useful plan-ts, the plan-ts
themselves or -the soil in which -they grow.
The appLicationalso discloses and claims see~s o.E useful
plants treated with an effective amount of a compound of formula
The compounds of formul.a I may also be in the form of
sa~ts, e.g. hyrochlorides, when in formu:La :t 1~1=11.
For the uses according to the invention of the copend-
ing applica-tion, -the individual compounds oi~ formula I, also in
admix-ture with one ano-ther, and the corresponding sal-ts are
equally valid.
Some of the compounds of formula I are known, namely:
2-thiazolidine-carboxylic acid and the lower alkyl es-ters thereof,
4-thiazolidine-carboxylic acid and the lower alkyl esters thereof,
N-acetyl-2-th:iazolidi.ne-carboxylic acid, the methyl este:r of N-
d.ichloroacety:L-4-th:iazol:idine-carboxy:~.ic ac:id,and N-acety.L-4-
th:Lazoli.dine-carboxyll.c ac:i.d.
Some of these known compounds, such as tl-le derivatives
of 4--thiazolidine-carboxylic acid, are useful as bios-timulan-ts
for agrarian uses. I'he others have been tested in the pharmaceu-
tical field as hepatoprotectors or intermediates for antibio-tics.
As far as we know, these compounds were never supposed
-to be associated with proper-ties of antidotes for herbicides.
-- 4
~v~
The compounds oE Eormula I are easily preparable by
acylation o.E 2- or 4-thiazolidine-carboxylic acid or oE the res-
pective alkyl esters with the suitable haloacetyl chloride, in
an inert solvent and in the presence o:E a halohydric acid-
accepting base.
As an alternative, acylation can be accomplished by
subs-ti-tuting the acyl halide by the corresponding anhydride.
The following compounds; N-dichloracetyl-2-thiazolidine-
carboxylic acid
HO-C--<
t NJ
f~-C~IC12
[metl-ting poin-t = 136-140 C; IR (cm ) : 1710 (~J COOH), 1660
l~) CO-N)], methyl ester of N-dichloroacetyl-2-thiazolidine-
carboxylic acid ~S
H3CO-C--
\NI--
~-CHC12
~melting point = 80-81 C; IR (cm ): 1740 ( COOCH3), 1670
(`J CO-N)] are new and :Eorm the subject ma-tter oE the presen-t in-
ven-tion.
-- 5
It has been furthermore observed tha-t N-acetyl-2-
-thiazolidi.ne-carboxylie aeid and the esters thereof with Cl-C~
alcohols possess, besides antidotic properties, also biostimula-t-
ing properties.
The action of these compounds, when employed as biosti-
mulants, results in a more luxuriant aspeet of the plants and in
an increase in -the harvest.
Thus, -the inven-tion of the copending application pro-
vides for -the use of N-aee-tyl-2-thiazolidine-carboxylie aeid and
10 of its esters with Cl-C~ aleohols as biostimulan-ts for eul-tiva-
tions of agrarian interest.
As menti.oned hereinbefore, the antidotes of formula I
ean be appii.ed to the useful eultivat:ions aeeordirlg to various
rnoclalities.
-- 6
Z3~:L
For example, they can be utilized for a preventive
treatmen-t of seeds, so that the plants developing thereErom
wlll be pro-tec-ted from the toxic actlon exer-ted by nonselec-
tive herbicides.
As an alternative, -the compounds of formula I are
employable for treating the plant itself or the soil in which
it grows. In this case, the antidotes can be distributed
alone or in combination with the nonselective herbicides.
The different types of applications require diEfer~
ent conditions which affect the practical aspects of the
-treatment, such as antidote amoun-t, period of treatment and
type of composition.
Other :Eactors in:Eluencing the practical aspects oE
the treatment are the type oE cultivation to be protected,
the non~selective herbicide employed, the climatic and environ-
mental conditions.
When the antidote is applied in a preventive seed
treatment, it is employable as such or, preferably, as a
proper composition.
2Q The compositions for the treatment of the seeds may
be in the form of powders, wetable powders or emulsiEiable
concentrates, and generally consist of the active compound
in amounts ranging from 0.5 to 95% by weight and of the usual
inert vehicles
\
~23;~
I which, depending on the composition type, may be solid,
¦ such as -talc, silica, diatomite, ben-toni-te, calcium carbon-
~ a-te and mixtures thereoE, or liquid, such as water, alkyl-
¦ aroma-tic hydrocarbons, acetone, cyclohe~anone and mixtures
thereoE.
The compositions may also contain suitable addi-
tives, such as surfac-tants, wetting agents, dispersants
and mixtures thereof.
As previously cited, -the antidote amount -to be
distributed on -the seeds vaLies as a function of various
factors, however, it is generally suEficient to use product
amounts ranging Erom 0.1 to 100 g/Kg oE seeds.
The treatments directly eEEected on the plant or
in the medium where the plant grows require, oE course,
that the antidote be used in the form of a suitable composi-
tion according to the usual practice for this kind of appli-
cation.
In the applications in which the antidote is distri-
buted on the vegetation or into the soil along with the non-
selective herbicide in a single formulation, the type of
formulation and the content vary both as a function o:E the
above-mentioned factors, and as a func-tion of the herbicide
type utilized and of the characteristics thereof.
The anticlote amoun-t to be used ranges from 0.1 to
10 Kg/ha and the ratio between an-tidote and herbicide in the
composition may range from 1:5 to 5:1.
~ ~r~
The following examples are given to better illus-
trate the present invention.
Example 1
~ntidotic Activity in Maize Plants by Preventive
Treatment of the Seeds
General modalities: 60 maize seeds were treated
with 60 or 120mg of the antidote to be tested, dissolved
in 3ml of an aqueous solu-tion of dimethylsulphoxide (DMSO)
at 3% by weight, or in 3ml of water optionally containing
a wetting agent at 0.1%.
On a basis oE 60,000 seeds/ha, the dose employed
was corresponding to 6~ or to ].20CJ oE antidote per hectare,
or corresponding to 2. 8 or 5.6g of antidote per Kg. of seeds.
The treatment was accomplished by mixing the seeds
for 10 minutes in said solution and then by allowing them to
dry during 24 hours, stirring them at interva]s in the course
of the first hours.
The treated seeds were then sowed a ground pre-
viously treated with the weed-killer heing tested, a-t a
predetermined dose. As a control, also mai~e seeds leEt
in a water bath not containing an~ antidote, under the
same condi-tions, were sowed.
After a 10-day growth under continuous light and
at a temperature o~ 25C, the antidotic activity was evalu-
ated by comparing the growth of the plants treated with
the weed-killer and with the
g
?
,;.,~.~s~ j
. ~ .~. ~,
~2~23~a
weed-killer plus the antido-te, wi-th the grow-th of the plants
-trea-ted neither wi-th the weed-killer nor with the antidote.
In the an-tidotic act.ivi-ty -tests, the following compounds oE
~ormula I were tested
A = N-acetyl-4-thiazolidine-carboxylic acld
= 4-thiazolidine-carboxylic acid
C = 2-thiazolidine-carboxylic acid
D = N-acetyl-2-thiazolidine-carboxylic acid
E = methyl ester of N-dichloroacetyl--4-thiazolidine-carboxylic
ac.id
F = N-dichloroacetyl-2-thiazolidine-carboxylic acid
G = methyl ester of acid C
H = methyl ester of acid F
I = methyl ester oE N-chloroacetyl-~-thiazolidine-carboxylic
acid.
The herbicides employed wexe Alachlor (chloroace-tanilide) and
Eptam (thiolcarbamate).
The results recorded on Eollowing Tables 1 and 2
reEer to the toxic action of the herbicide in the presence of
the antidote on the maize plants and are expressed accordin~
to a scale of values Erom 4 (complete stop o:E growth or
death of the plant) to 0 (plant growth like that of plants
not trea-ted with herbicide and antidote).
-- 10
. . ,
~2~23~
As a consequence, an evalua-tion equal to that of the
herbicide alone is indicative of the absence of an antidotic
effect, while lower values are indicative of an an-tidotic
effect increasing towards the lower values.
Preliminary laboratory tests proved that -the anti-
do-tes of formula I are not toxic for ma:ize and that the
herbicide activity o~ Ala.chlor and Eptarn towards the common
infesting plants of maize (Solanum nigrum, Amarantus spp.,
Echinochloa spp., Digitaria Spp., Setaria spp., Sorghurn_
_~lepense, Panichum dichotomiElorum, ~yperus rotundus,
Cyperus esclulantus) is not a:Efected by -the presence of
....
the antidote in this kind of tests.
`; ~
J Table 1
~ Antidotic ac-tivity by preventlve trea-tment oE maize seeds.
3 Herbicide: Alachlor
:, An-tidote g of anti- Antidote Toxic action on maize ex-
dote/lO00 solution erted by the herbicide at
g of seeds a dose of:
16 Kg/ha 8 Kg/ha
¦ A 2.8 H2O 2 2
B 2.8 H2O 2-3 2-3
C. 2.8 H2O .l
D 2.8 H2O 2
E 2.8 H2O/DMSO 3% 2
F 2.8 H2O/DMSO 3% l 0
G 2O8 H2O/DMSO 3% 2
H 2.8 H2O/DMSO 3% 1--2 0
12
-il
Table 2
An-tidotic activity by preventive trea-tment of maize seeds.
Herbicide: Eptam
Antidote g of anti- Anticlote Toxic action on maize ex-
dote/1000 g solution erted by the weed-killer
of seeds (1) at a dose of:
4 Kg/ha2 Kg/ha
_ _ - 3 2
C 2.8H2O/DMSo 3% 2
C 5.6~-12O/D~SO 3% 1 0
C 2.8H2O/wettiny
agen-t 0.1% 1 0
C 5.6H2O/wetting
agent 0.1% 1 0
C 2.8H2O/wetting
agent 0.5% 0
G 2.8~I2O/DMSO 3% 2
F 2.8H2O/DMSO 3% 0 0
H 2.8H2O/DMSO 3~ 0 0
I 2.8H2O~DMSO 3% 2-3
Notes to Table 2
(1) As a wetting agent there was indifferently utilized
"Tween 20" (registered trademark of Atlas Co. for
sorbitane monolaurate polyoxyethylated with 20 moles
of ethylene oxide per mole of substrate) or "Emulson
20 OM" (registered trademark of ROL Co. for sorbitane
oleate polyoxyethylated with 20 moles of ethylene
oxide per mole of substrate).
- 13
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