Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
The present invention relates to the use, as agents for
regulating plant growth, of a certain amido-thiono-phosphoric acid
ester, which is a known compound.
It is already known that similar amido-thiono-phosphoric
acid esters have herbicidal properties (see German Auslegeschrift
(German Published Specification) 2,001,771).
It is also known that a product which is commercially
available under the trade name "Off-Shoot-T" and is based on fatty
alcohols with 6, 8, 10 and 12 carbon atoms can be employed for
regulating plant growth, in particular for suppressing the growth
of side shoots of tobacco (see Farm. Chem. Handbook 1975, Meister
Publishing Co., Willoughby, Ohio, 1~75 and Pesticide Dictionary D
147). However, the action of this product is not always satisfactory,
l especially when low amounts are used.
,;`j
It has now been found that the compound O-(2-nitro-4-
methylphenyl)-O-methyl-N-isopropylphosphoramidothioate of the
formula
~, '
NO~
~ 3 > S ~ CH3 (I)
! /HC-HN
, /
H3C
is particularly suitable for inhibiting the growth of side shoots
(suckers) on tobacco plants.
Accordingly, the present invention provides a method for
inhibiting the growth of side shoots on tobacco plants which
comprises applying to the plants or their habitat an effective amount
of 0-(2-nitro-4-methylphenyl)-O-methyl-N-isopropyl-phosphoramidothio-
, .:
7 ~3
ate of the formul.a
N2
H C \~ I O ~ - CH3 (I)
Surprisingly, the compound tI) which is used according
to the invention exhibits a considerably more powerful side shoot-
inhibiting activity on tobaeco plants than Off-Shoot-T, which is
known from the state of the art and is an active compound of hiyh
aetivity and the same type of aetion. The substance used according
to the invention thus represents a valuable enrichment of the art.
The eompound (I) used according to the invention is
known (see German Auslegeschrift (German Published Speeifieation)
2,001,771). However, its use for regulating plant growth, speeifi-
eally for inhibiting the growth of side shoots on tobaceo plants,
is new.
The compound I used aceording to the invention can be
prepared by a process in which
(a) an O-methyl-N-isopropyl-amido-thiono-phosphoric aeid
ester halide of the general formula
H3C ~ S
/ P-Hal (II)
7 3 N
in whieh Hal represents ehlorine or bromine,
is reaeted with a phenol derivative of the general formula
N ~ CH3 (III)
3~7
.~
in wh.ich M represents hydrogen, an alkali metal or ammonium, if
appropriate in the presence of an acid-binding agent, such as
potassium carbonate or sodium carbonate, and iE appropriate in the
presence of an inert organic solvent, for example acetonitrile,
a-t temperatures between 30C and 110C, preferably between 40C and
70C, or in which
(b) an 0-(2-nitro-4-methylphenyl)-N-isopropylami.dothiono-
phosphoric acid ester halide of the general Eormula
NO
Hal S ~CH3 ( IV)
: i-H7C3-NH
in which Hal has the meaning stated above,
'~l, is reacted with an alkali metal methoxide of the general formula
I M'-O-CH (V)
:il, in which M' represents sodium or potassium, :~
i in the presence of an inert organic solvent, for example a lower
:l alcohol, at temperatures between 30C and 110C, preferably between
:, 40C and 70C, or in which
.. (c) an O-methyl~O-(2-nitro-4-methylphenyl)-thionophosphoric
acid ester halide of the general formula
NO~
\ P - o ~ = C~3 (VI1
in which Hal has the meaning stated above,
, is reacted with isopropylamine in an inert organic solvent, such as
acetonitrile, at temperatures between 30C and 110C, preferably
between 40C and 70C.
- 3 -
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.
' ~ ': ` ` , .` ' ' ' .' ` , , ' , ,' . ' ' : ~ . ., , ,
,.' '. ' '., ' i , ' , : ': ' . ~, : . , '
~ 3~
Experience -to date of the mode of action of plant
growth regulators has shown that an active compound can exert one or
` several different actions on plants~ The actions of the compounds
depend essentially on the point in time at which they are used,
relative to the stage of development of the seed or of the plant,
. and on the amounts of active compound applied to the plants or
their environment and the way in which the compounds are applied.
In the present case, compound (I) has outstanding properties when
used on tobacco plants, normally at the stage of removing the apical
vegetative tips, in the inhibition of side~shoot or sucker growth.
This provides the preconditions for being able to carry out complete
mechanical or manual harvesting o~ tobacco plants in only a single
pass.
The active compound (I) can be converted into the cus-
tomary formulations, such as solutions, emulsions, suspensions,
' powders, foams and ULV cold mist and warm mist formulations.
These formulations may be produced in known manner,
for example by mixing the active compounds with extenders, that
is to say liquid or solid carriers, optionally with the use of
surface-active agents, that is to say emulsifying agents and/or
dispersing agents and/or foam-forming agents. In the case of the
use of water as an extender, organic solvents can, for example,
also be used as auxiliary solvents.
As liquid diluents or carriers, especially solvents,
there are suitable in the main, aromatic hydrocarbons, such as
xylene, toluene or alkyl naphthalenes, chlorinated
- 4 -
, ~"
;~ ' . ' ~" , ` ' ' ` ' .; ' ' " ' , ' ' ' ` ` " ' ' ' ` ~
~3~'77'~
aromatic or chlorinated aliphatic hydrocarbons, such as
chlorobenzenes, chloroethylenes or methylene chloride,
aliphatic or alicyclic hydrocarbons, such as cyclohexane
~` or paraffins, for example mineral oil fractions, alcohols,
such as butanol or glycol as well as their ethers and
~, esters, ketones, such as acetone, methyl ethyl ketone,
methyl isobutyl ketone or cyclohexanone, or strongly polar
solvents, such as dimethylformamide and dimethylsulphoxide,
as well as water.
As solid carriers there may be used ground natural
minerals, such as kaolins, clays, talc, chalk, quartz,
attapulgite, montmorillonite or diatomaceous ear~h, and
ground synthetic minerals, such as highly-dispersed silicic
acid, alumina and silicates. As solid carriers for granules
` 15 there may be used crushed and fractionated natural rocks
such as calcite, marble, pumice, sepiolite and dolomite,
as well as synthetic granules of inorganic and organic
meals, and granules of organic material such as sawdust,
coconut shells, maize cobs and tobacco stalks.
As emulsifying and/or foam-forming agents there
may be used non-ionic and anionic emulsifiers, such as
polyoxyethylene-fatty acid esters, polyoxyethylene-fatty
alcohol ethers, for example alkylaryl polyglycol ethers,
alkyl sulphonates, alkyl sulphates, aryl sulphonates as
well as albumin hydrolysis products. Dispersing agents
include, for example, lignin sulphite waste liquors and
methylcellulose.
Adhesives such as carboxymethylcellulose and natural
and synthetic polymers in the form of powders, granules
30 or latices, such as gum arabic, polyvinyl alcohol and ;~
polyvinyl acetate, can be used in the formulations.
It is possible to use colorants such as inorganic
pigments, for example iron oxide, titanium oxide and
Prussian Blue, and organic dyestuffs, such as alizarin
~ 35 dyestuffs, azo dyestuffs or metal phthaloFyanine dyestuffs,
::
~ Le A 19 119
!
,., ., .: : ` , : ' : ,: ' : ' . .:, . .
77~;3
~ and trace nutrients, such as salts oE iron, manganese, boron,
?,~ copper, cobalt, molybdenum and zinc.
The formulations in general contain from 0.1 to 95 per
cent by weight of active compound, preferably from 0.5 to 90 per
; cent by weight.
The active compound according to the invention can be
present in the formulations as a mixture with other active compounds,
such as fungicides, insecticides, acaricides and herbicides, and
- also as a mixture with fer-tilisers and other growth reyulators.
` 10 The active compound can be used as such, in the form of
its formulations or as the use forms prepared therefrom, such as
ready-to-use solutions, emulsifiable concentrates, emulsions, foams,
suspensions, wettable powders, pastes, soluble powders, dusting
agen-ts and granules. These may be used in the customary manner,
for example by watering, spraying, atomising, scattering, dusting,
` foaming and gassing.
- The active compound concentrations can be varied within
a substantial range. In general, 0.01 to 50 kg, preferably 0.05 to
10 kg, of the active compound are employed per hectare.
In the following Example, the activity of the compound (I)
. , .
used according to the invention is illustrated.
,~ The known comparison compound is identified as follows:
Off-Shoot-T = a commercially available growth regulator based on
~ fatty alcohols with 6, 8, 10 and 12 carbon atoms.
;~ Inhibition of growth of side shoots of tobacco
; Solvent: 30 parts by weight of dimethylformamide
Emulsifier: l part by weight of polyoxyethylene sorbitan monolaurate
To produce a suitable preparation of active compound,
,
-- 6
. . ~
.
. ~
! 1 part by weight of active compound was mixed with the stated
amounts of solvent and emulsifier and the mixture was made up to
the desired concentration with water.
Tobacco plants were grown in a greenhouse until the 7th
foliage leaf had unfolded. In this stage, the apical vegetative
l tips of the plants were removed and the plants were sprayed with
'f the preparations of active compound until dripping wet. After 3
I weeks, the side shoots of the planls were broken ofE and weighed.
i The weight of the side shoots of the treated plants was compared
with that of the control plants. 100% inhibition denoted the
absence of side shoots and 0~ denoted a growth of side shoots which
corresponded to that of the control plants.
The active compounds, active compound concentrations
and results can be seen from the table which follows.
T A B L E C
Inhibition of growth of side shoots of
tobacco
Active Compound Active compound con- Inhibition of
centration in ~growth in ~
3~ :
' 20 - - =
(control)
Off-Shoot-T 0.2 20
Compound (I) 0.2 92
Compound (I) 0.4 99
Compound (I) 0.6 99
_eparative Examples
Example 1
3 \ p _ O ~ CH3 (I)
i-EI7C3N ~
q~'7~
18.8 g (0.1 mol) of O-methyl-M-isopxopylamidothiono-phosphoric acid
ester chloride were added dropwise to a mixture of 15.3 g (0.1 mol)
of 2-nitro-4~methyl-phenol, 14.0 g of anhydrous potassium carbonate
and 100 ml of acetonitrile at 50C to 60C, whilst stirring intens-
~ ively.
- The mixture was stirred at 70C for a further 5 hours in
order to bring the reaction to completion. The inorganic salt
formed was filtered off and the filtrate was distilled to remove
the solvent. The residue was taken up in 100 ml of benzene and
the benzene solution was washed with 1% strength aqueous sodium
carbonate solution and dried over anhydrous sodium sulphate. After
distilling off the benzene and recrystallising the residue from a
mixture of carbon tetrachloride/n-hexane, O-t2-nitro-4-methylpheny~-
O-methyl-N-isopropylphosphoramidothioate was obtained. M.p. 54-
56C.
.
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:, . . , , ,:, :, . .
