Note: Descriptions are shown in the official language in which they were submitted.
1147729
This present invention relates to new herbi-
cide compounds and, more particularly, to new formamidine
. sulphides and disulphides
114'7729
- 2
and to thiocarbamoyl guanidines endowed with a high herbicide
activity, to the use and the method of preparing same.
A restricted number of formamidine disulphides is known in
literature, however herbicide properties were never recognlzed
to such com~ounds.
P,K. Srivastrava et al. prepared, for merely academical purpo-
ses, the following formamidine disulphides in the form of hromo
hydrates: -
C6H5 / 6 5
N N . 2HBr~P~K. Srivastrava et al.,
C \ / C \ Tetrahedron Letters 23,
NH S-S NH 2725, 196B)
C6H5 C6H5
C 11 -C13 / C~2-C6~
N N. 211Br (P.K. Srlvsstrava et al.,
C / C \J. Ind. Chem. Soc. 40,
~2N S-S N1~2 803, 1963)
1~47729
-- 3 --
C6H / 6 5
N N . 2HBr (P ~ . Srivastrava et al.,
Il . .
/ C \ / C \ Indian J. Chem. 1, 354,
HN S-S NH 432, 1963)
CH3 CH3
However no analytical data for the characterization of the
abovesaid three compounds are reported, probably because, due
to their instabillty, they cannot be isolated as free bases.
Similarly, from the technical literature only a limited number
of derivatives belonging to the class of thiocarbamyl-guanadi-
nes are known. To this class of compounds too, had never been
previously recognized herbicide properties.
lleld, Gross and Schubert / Zeitschrlft der Chemle 13, 341 (1973),~
by oxidation of the N,N-dimethyl-N'-phenyl-thiourea wlth thlo-
nyl chloride, prepare N ,N -dlmethyl-~ ,N dlphenyl-~ -~N,N-dl-
methyl-thiocarbamoyl/-guanadine of the formula:
C6135
N
/C\ /C6~35
3 I N
CH3 S=C N(C13)2
~1~7729
-- 4 --
Srivastrava et al. /J. Ind. Chem. Soc. 40, 803 (1963)/ prepar-
ed derivatives of thiocarbamoyl-guanadine non substituted on
the nitrogen atom in position 1 and on the nitrogen atom of
the thlocarbamoyllc group in the form of bromohydrates.
We have now found, and this forms an object of the present
invention, formamidine sulphides and disulphides of general
formula I and thiocarbamoyl guanidines of general formula II:
R R R \
N N . N
Il 11 11
R - N / ~S) N - R R - N N - C - N - R
n l2 R2 1 11 !2
(I) ~II)
In both formulae I and II:
R - phenyl optionally substituted by one or more halogen atom~,
one or more al~yl or haloalkyl groups having from 1 to 3
carbon atoms7
R and R ~like or unlike each other) = alkyl C1-C3, alkoxvl
C -C
or R and R to~ether are the group -CH2- (CH2)3- CH2 or
tle grOUP - Cll2 - C112 - O - Cll2 2
~ ~ . . .
,' ~
.
~147729
n = 1 or 2;
provided that when in formula II Rl = R = CH3, R be a
substituted phenyl.
Compounds of formulae I and II, even in the
case in which in formula II R = R = CH3 when R =
unsubstituted phenyl, are endowed with herbicide activity
against both monocotyledons and dicotyledons and can be
usefully utilized, as such or in form of suitable compo-
sition, in the fight against infesting weeds, the
method for fighting infesting weeds by using compounds
of formulae I and II and compositions thereof being a
second object of the present invention.
The preparation of the compounds of formulae I
and II, which forms a further object of this invention,
is achieved according to the processes herebelow des-
cribed.
The compounds of general formula I are prepared
by oxidation of trisubstituted thioureas (III) in the
presence of an organic base (reaction 1), so obtaining
the compounds of formula I in which n = 2 (disulphides),
from which, by desulphurization in the presence of
triphenylphosphine (reaction 2), the corresponding
sulphides are obtained. The same compounds ~mono-
sulphides) can be obtained also by reacting a trisubsti- --
tuted thiourea (III) with the proper imidoyl-chloride
(IV) in the presence of a halogenhydric acid accepting
base (reaction 3)
S Rl R R
Il / \ / (I,n=2)
1) R - N~ -C - N oxidants~ C
S--S
Rl_N N_Rl
1 12 ,-
R2 R
~ - 5 -
1147729
2) (I, n=2) + (C6H5) 3P (I, n=l) + (C6~I5) 3P=S
Cl Rl
53) (III) + R - N = C - N (IV) base ~ (I, n=l)
R2
Reaction 1 is conducted by oxidizing thiourea
(II) in the presence of an organic base and in an inert
solvent.
As oxidizing agent it is possible to use, for
example, a halogen such as bromine and iodine (Br2, I2),
while a tertiary amine such as triethyl- or tributyl-
amine can be used as an organic base.
Excellent yields were obtained by employing
methylene chloride (CH2C12) or chloroform (CHC13) as a
solvent.
Under the conditions described hereinbefore
the reaction occurs at room temperature and in very
short times. At the conclusion of the reaction the
mixture is washed with water and anhydrified, and
the solvent is evaporated. The resulting product can
be utilized as such, otherwise it can be crystal-
lized from non-polar solvents.
Reaction 2 can be advantageously conducted by
reacting equimolar amounts of disulphide (obtained from
reaction 1) and triphenyl-phosphine, in diethylether
at about 0C.
The resulting triphenyl-phosphine sulphide
precipitates and is removed by filtration at the end
of the reaction. The reaction mixture is treated according
to usual laboratory techniques and the formamidine
- '
114772~
sulphide so obtained is purified by crystallization
from hydrocarbons.
Reaction 3 directly leads to the obtainment of
formamidine sulphides without preparing first the
corresponding disulphides.
The reaction is conducted in an aprotic
solvent and in the presence of a halogenhydric acid-
accepting base.
An advantageous process for conducting the
abovesaid reaction consists in adding a solution of
the thiourea derivative ~II) and of a slight excess
of base (tertiary amine) in methylene chloride, to a
solution of imidoyl-chloride ~III) in the same solvent.
The mixture is stirred at room temperature
and the reaction occurs in a short time.
The product is then isolated according to the
usual laboratory technique.s.
The preparation of the compounds of General
Formula II is achieved by reacting a formamidine sulphide
or disulphide (I) with a catalytic amount of a strong
anhydrous acid (reaction 4)
R R
~ /
N N
Il 11
1 / ~ / N - Rl (I) H > (II)
1~47729
Reaction 4 is preferably achieved by adding a
catalytic amount of an acid ha~ing a sufficient force to
salify the basic groups of the sulphide or disulphide
of Formula I, to a solution of this latter in an aprotic
polar solvent such as for instance
11~7729
chloroform (CHCl3).
~s a strong acid there may be used an anhydrous halogenhydric
acid or a trihaloacetic acid.
The reaction rate depends, besides on the nature of the for-
mula I compound that is made to react, also on the amount of
acid used.
~or amounts of acid equal to 0.1 e~uivalents per mol of com-
pound of formula I, reaction 4 is complete also at room tempe-
rature within a few minutes.
Once the reaction has taken place, the chloroformic solutlon
is washed with a saturated aqueous solution of sodium bicar-
bonate ~NaHCO3) and is then anhydrified. The solvent is then
evaporated under vacuum, thereby obtainin~ as a residue the
corresponding compound of formula II which may thereu~on be
puri~ied by crystallization.
The process for the prcparation of the compound.s of qeneral
formulae I and II can be sumarizcd a3 rcpor~cd in tlle ~ollow-
inq scheme 1
1147729
~+
U~ _
:C ..
,, ~o ,,
U ~
H
~ . /~
. ~; ~
O \/
_I ~
~ ~, U--U
_ :~ _
I ~ +
a~ v~
a
S Z
O
~1)
- ' '
.. . .
.
-
11~7729
The compounds of formulae I and II reported in the following
Table 1, have been prepared according to the processes here-
above described.
~, .
r. ~ ~
~47729
~ d d ~ . ~
~'I b ~ ~. .
N _
Z N
Z_ t~ _ .
H ~r \Z~_N~ ,0 u~ g~ (t) O ~ t' O
~1 ~ >~ r~ C ~ 7 u~ ~ ~
, . I .. _
C 0 O O O O d 1~ ~ ~ O
~1 ___ O I Z ~ I Z
Z _ ~ ~ ._ I zN
N
C~ ~ Y~ Y ''
O O _ - -
~ ,.` - ' ' ' ' ~
- 13 -
7729
r ~ ~ O
. O
~ 'oo
. . . .. .
~ O~ O 0 O
â
. _
~.~ .. __ _
U) 10 O ~t ~ N ~D . t` 0 ~
7 ~ ~ u~ . ~ ~ o u 0 u~ ~ ~
~ . .. .
C . 0~ t` UJ O g U) ~ ~ ~0 C~l ~ 0
~ ~ ~ U ~ - ~ ~ ~ ~ ~ ~ o
I~ . ~ I z ~ I Z ~ I Z L) I Z
. __
~ ~ ~ ~ ~ 1~ '
~ :~ ~ ~
~ S) I L.) T
--_ 1 1 ~ S S
H F ~ ~ ~_
~J o~ ~ u~ ~o ~
O .)
.~ ._ _.
~ ~ E _ _ _ _
.- U 11 _ _ __ , .. _ ._
~ : -
.
., .
- 14 -
2~
Z Z N N N
_1~ , . __ O
~ ~ ~ ~ . O ~ 0
N ~ 0 O
~ , ~ _
-X
_ C ~ ~ ~ . ~ 1~ ~ ~ ~O 0~ ~ ,
C ~ 1~1 L~ ~ 'J') ~ It~
_ _.
C . U1 ~ ~ ~ 0 0 O ~ ~ ~ ~ ~
G~ O ~D ~ C Z ~n Z ~ T Z (_) I Z
N O N ~ r O ,.
Z O Y ~ ,_ . ._ . - ,
_ q ~' Y
H _ _ N _ _ _ _
O o- 0 a~ ,o' .
._ ,
~ " .
,
11~'7'~9
- 15 -
N N _ ~t ~t
4~ 3 U~ ~t a ~t 'n u~ ~Nt co ~t CO ~t Nn
S ~ ZCC~ u7Z~ ~ ZN ZCC~ n Zcc~ ~
~ I ~t ID R N I ~ CC ~t
~- æ æ ~OD
F~ ~n ~ ~n ~
cr ~ ~ ~ n
~ CLl __ _ _ _ U~ _
N ~ l n r~ CD n
~, _ _ E
-- N
~ ~_
1-- N
_
._ Ct`o C~ ~i C ~ ~ I" LCO~ ~t ~g un~ CD a~
C ~ ~S~ u~ a ", u; cn ~ rr, a et ~ co ~t O
C ~ N ~ CO r- COCO Ir) CO '?, U ~ N In a. O
E O ~ ~ U~ ~ ,o ~D , ~unt ~ a- et ~ ~t ~
,~ S ~0 L~ I Z L~ T Z L~ C Z L7 I Z L) T z
LY N I " ~ ~`J I O
_ _ . 1~ _ _ .
Cr~.I N 3:
: ~ ~ ~ n n
1~ Ll ~ ~t ~t
V ~ ~0 )~ _
~--1 ~ . ~ N N
a.) ~. .
[ ~ ~ ? N ~ U~ ~D
O E _ _ _ _
O 1. _ _ ._.__
,., " ~ . , : ' '.~
~1~'7t729
r - ~ ~ ~ ~ ~ ~ ~L-D ~ zm m Z~D r~
L T O I ~) 0 N 0~ I ~ 11~ I 0
.~ ~
_ ~ 0 0 0 ~ ô 0
~ O ~ _~O ~ æ Y~
~c' I 1 , ~o ~ ,~
i I _
I
_ C ~O N
1~
~ c ~ 01 0 1~1 ~ N 5~3 U~ r- tO ~ ~ N 1~ 0
~ .t) ~O (-- &~ ~ o 0 .-- ~I ~ O _ ,.
.~ ~ N ~0 1') ~ <O N a- 07 1~) 1~ t`
r o ~ ~o ~o 1 53 ~o 0 ~ ~ a~ o
m z
~K ~0 t~ ~ :C~ l Tr'
~ cm ~ I m ~ r~ m
H N N . . _
'D __ .. _
to ~ ~0 ~ 0 O. æ N ~I
~ _ ____ _ ___ _ _
O ~ .___ _ _ _
,,~ ., .,: . . .
,
1147729
I l .
O O ~N
~'/ O U r~l N ~ ~ ~ .
_ ~ ~ æ _ _ . ~ 2 æ
~ O 'O 0~
~ ~ ~ ---- N ~ ~
3~o o~
e o N -
N _ 1 ~.)
~ ~ __ _~N _
_ 1
H ___ _
O O O 1~) . _ N
'0J _ ___ _ L
- 13 -
1~477~9
.. ._
L ~ ~r) ~ N cn
r Q a)Z N N ~ I ~ ~ ~t
. _ - .~ ____
,~ ~ 0~
__ __ _ ____
N ~ ~J N N ~-~
. ~L~' ~ _
E ~ ~0 01 ..
r~ N N
.__
._ X ~ ~J ~ N I~J Y;~ O 0
J ~t ~~g (D r- ~ ~ D
,, ~e .___ ... ___
~ S <D ~ ~ ~ ~ ~ æ ~ ,~
. N _ . I Z ~ I Z
_ _ .. . _._. T y N
~1 ~r, I N L~ N~
r L) T
. I _
Y I D L~
Q:L7
~ 'O _ .__
~ 1 O N N N N
~) -~-
o ~ - =----= =
1~7 ~9
.
E . L17 ~ O ~D O rJ ~ ~ ~n ~
L7- L~ L\l Ltl Z~ r~ Z L~ ~O ~D
_'r ~_ _ __
l"_
_ _- __ ___ _.
L~ 'n (n ~ ~1l ~ .-l
_
~^~
. ~
._ ~L7~ L~ LD ~ L'J D LJI 0 N L,o 1;~ ~ LD t--
o ~ ~ ~ ~ o In ~ ~ o. o LD
ru _ n ~ 0 ~D ~ ~ N "7 0 N 3 N 0 L''l
~u n n n ~ io Ln ~ ,n m , o gl LD
LLI ~ L~ ~ Z L~ I Z ,~ T Z ~ T Z Z 1~ rJ7
'~ ~ ~ _
IL~7 , ~L~I Y
~-- L_J 1 L 7 L~ ~ ~ C N T
_
~1 Cr: ~D LD Y LD Y rD
C~
~ g Z L~') "~ N~ "~ ~S r~
O ~
:. :
11477'~9
- ~n -
~ . " . I
".~- _
,,~,
_ _
N . N m b
_ _
P:
. D ~. _ __ _
._ ~ G G O G~
r3 r U) t`- n ~ N d' r~
_ _ ~JI ~ o N 0 0 0 .
F: L U) J ~ O ~i 'J O
IIJ ~ _ ~) :CZ ~ Z
L~:~ N ~N 1~ N
~ --~ ~N
_l~- o ~/ ~-- ~n
t~o n ~
,..
~4~7'~9
The compounds of general formulae I and II are
endowed with a high herbicide activity exerted against
both monocotyledons and dicotyledons.
The data relating to the activity of some
representative compounds, obtained as described in
example 5, are reported in the following Table 2.
The herbicide activity was tested on the
following weeds:
Monocotyledons
A = Echinochloa crusgalli
B = Avena fatua
C = Lolium italicum
D = Sorghum spp.
E = Setaria glauca
F = Digitaria sanguinalis
G = Alopecurus myosuroides
H = Panicum dichotomiflorum
I = Festuca pratense
J = Bromus sterilis
K = Poa annua
Dicotyledons
L = Stellaria media
M = Ipomea purpurea
N = Vigna sinenbis
O = Rumex acetosella
P = Galinsoga parviflora
Q = Convolvolus sepium
R = Convolvolus ariensis
S = Geranium dissect
- 21 -
1147729
T = Sida spinosa
U = Brassica
V = Gypsophila muralis
W = Galium aparine.
The data relating to the herbicide activity
reported in Table 2 are expressed using a scale of
values from O (no herbicide activity, growth of the
plant like that of the check) to 4 (death of the
plant or complete stop of growth).
- 22 -
1 ~
- 23 - 1147~Z9
.- ... ~ .. ~__
~ ~ ~ r ~ ~ ~r
~r ~:r ~:r ~ ~r ~ ~r ~r
~r ~ ~r ~r ~r 1 ~ ~r
OP~ ~r ~ ~r
O' ~er er ~ ~ q~ ~er ~
Z ~r ~ ~ ~ ~ ~ ~r ~r
~: ~r ~ ~:r ~ ~ ~ ~ ~ ~:r ~ ~r
~r ~r ~ er er ~r er ~r ~r ~ ~r
_ _ . _ ,_ ._ _ _ _
~ ~:r ~r ~r ~r
~ ~r ~r ~r ~ ~r~
C 5: ~ ~r ~r er ~r ~r~r
~5 ~ ~ ~ ~ ~ ~r
~r ~ ~ ~ ~ ~er
0~ ~r~r ~ er ~ ~ ~r
er .:r ~ ~r
t~ r ~ ~ ~ ~
~ ~ ~r q~ ~;r ~ ~ ~:r ~
. _ , ~
Q) .C D ~ C`l D D ~D D ~ ~D D ~) N
a x
___ ___
~ ~ Q) a) ~ ~ c) qJ
a)u~ 3 ~3 3 3 3 ~ ~3
C ~- ~ t~' tJ~ ~ ~ h a) ~ t7~ ~
v F, E , v F V F F , v
E~ ~/ O O a) O o o o Q) o ~ O
,_,__, __. I __ P. 1- __ ~ __ l
-
æ
~ u~ ~c o ~o .n
FO~'~ I
11477'~9
Depending on the particular compound, the best
effectiveness of the herbicide activity is achieved by
application in pre-emergence or in post-emergence, that
is when the infesting weeds have not yet emerged out of
soil or when they have.
The herbicide compounds of the invention prove
also to be selective with respect to usefull cultivations
such as wheat, maize, soja and cotton.
For agricultural applications the active com-
pounds are distributed on the soil as such or~ preferably,
in form of suitable compositions consisting of one or
more of the compounds of formula I as active principle
and one or more suitable carriers. Suitable compositions
include wettable powders, liquid pastes, granular
formulates and so on.
Suitable carriers include, depending on the type
of composition, silica, kaolin, diatomaceous earths,
bentonite, pomix, organic solvents, water and so on.
In the composition may be included also addi-
tives such surfactants, emulsifiers, thickners and so on.
A list of carriérs and additives is reported on
" Mc Cutcheons-Detergent and Emulsifiers-~orth American
and International Editlons, 1977 Annual. Mc.Cutcheons
Publ. Co., Glen Rock, New Jersey (U.S.A.)".
The preparation of said compositions is carried
out according to procedures common to the formulative
praxis.
If desired in the compositions may be included
also other active ingredients such as fertilizers,
insecticides or fungicides. The amount of active
principle (Compounds of formulae I and II) to ~e
distributed on the soil depends on various factors such
the enviro~lent~ conditions, the kind of ag~icultural cultivation
- 24 -
~1
11477Z9
to be protected from infesting weeds, the type of composi-
tion and the particular active principle.
Generally, amounts of compounds of formula I
and II comprised between 1 and 6 kg/ha are suitable for
obtaining good results in the fight against lnfesting
weeds, the preferred amount being of about 2-3 kg/ha.
The following examples are given to better
illustrate the present invention.
EXAMPLE 1
Preparation of Nl, Nl-dimethyl-N2-phenyl-formami-
dine disulphide (Compound n 18, Table 1). ~Reaction 1).
.,
11477A~9
- 26 -
A chloroform solution of lodine (5.2 g ln 100 ml) was added
dropwise and under stlrrin~ to a solution of N,N-dimethyl-
-N'-phenyl-thiourea (5 g, 0.0277 moles) and triethylamine
(7.5 ml) ln chloroform (50 ml).
The addltion was continued until the lodine colour remained
persistent in the reaction mixture.
After 15 mlnutes the stirring was stopped and the reaction
mlxture repeatedly washed wlth water (750 ml) and anhy-
drlfied with anhydrous ~a2SO4. After removal of the solvent
a yellow oll was obtalned whlch, crystallized from n.hexane,
provlded 4 g of the product to be obtained.
EXAMPLE 2
Preparatlon of N ,N -dlmethyl-N -phenyl-formamide sulphide
(Compound No. 17, Table I). (Reactlon 2).
A solution of N ,N -dlmethyl-N -phenyl-formamldlne dlsulphide
pre~arcd as dcscrlbed ln Examplc 1 (350 m~) ln diethylcthcr
(2 ml) was additioned, under stirring, wlth 256 m~ of triphe-
nyl-phosphine, while outside cool1n~ by means of a water and
lce bath.
After conclusion of the reaction ~about 3 hours), the white
preclpitate of triphenyl-phosphine sulphidc was removed by
filtratlon at 0C.
1~47729
The solvent was then removed under vacuum and the residue,
crystallized from n.hexane, provided 112 mg of the desired
product free from impuritles.
EX~MrLE 3
Preparation of N ,N -dimethyl-N -phenyl-formamide sul~hide
~compound No. 17, Table I). (Reaction 3~.
A solution of N,N-dimethyl-N'-~henyl-thiourea (0.9 g) and
~hos~en ~COCl2~ ~2 g), in methylene chloride, was stirred
for 8 hours at room temperature. After removal of the solvent
under vacuum, the residue ~imidoyl chloride) was dissolved
ln a solutlon of triethyl-amine(0.7 ml) and anhydrous methy-
lene chloride ~20 ml).
A solution of N,N-dimethyl-N'-phenyl-thiourea ~0.9 g) and
triethyl-amine ~0.7 ml) in methylene chloride ~20 ml) was
added dro~wlse, under stirring and at room temperature to
the above mentloned solutlon.
Aftcr an ei~ht-hour stirring thc reaction mixture was wash-
ed wlth the water, anhydrified with anhydrou~ sodium sulphate,
and the solvent was removed under vacuum. The res~due was
crystallized from petroleum ether, so obtainlng 1.4 g of the
desired product (yield = 86~).
- - 28 -
~ 47729
EXAMPLE 4
Preparation of N ,N -dimethyl-N ,N -diphenyl-N -/(N,N-dlme-
thyl) thlocarbamoyl/ guanidine (Compound n. 27, Table I)
(Reactlon 4).
43 ~l of trifluoroacetlc acid were additioned to a solution
of N ,N -dimethyl-N -phenyl-formamid~ne-dlsulphide (2 g, S,58
mols) obtalned as descrlbed ln Example 1 in chloroform
~200 ml).
The reaction mlxture was then allowed to rest for 15 min.
at room temperature, after which lt was washed wlth a satura-
ed ~olutlon of NaHCO3, and anhydrlfled wlth anhydrou~ Na2SO4.
After removal of the ~olvent by evaporatlon under vacuum, the
re~idue was crystalllzed from n.hexane/benzene (70:30).
1.3 g of the deslred product were obtained ~yleld 71%).
EXAMPLE 5
Determinatlon of the herblclde actlvlty.
Some pot~ were prepared (upper dlameter ~ 10 cm, helght = 10
cm) whlch contalned sandy oll, and each pot was ~owed with
one of the lnfestlng weeds llsted on pages 21 and 22. To
each pot water was added ln the amount necessary to a good
sproutln~ of the ~eed~.
. ... ..
1147729
The pots were divided into three sets.
The first one was not treated with any herbicide
and was used as a check.
The second set was treated) one day after sowing,
with a hydroacetonic dispersion (20% by vol./vol.) of the
compounds of the invention, in order to determine the
herbicide activity in the pre-emergence stage.
I'he third set was treated, 15 days after sowing
(namely when the little plants had already reached a height
of 5-10 cm, depending on the species) with a hydroacetonic
dispersion (20~ by vol./vol.) of the compounds of this
invention in order to determine the herbicide activity in
the post-emergence stage.
All the pots were kept under observation in a
conditioned chamber at temperatures ranging from 15 to
24C, relative humidity = 70~, photoperiod = 12 hours,
light intensity = 2500 lux.
Every second day all the pots were uniformly
watered in order to secure a humidity degree sufficient
for a good growth of the plants.
28 days after the treatment, controls were
carried out to ascertain the vegetative stage of the
plants, the results thereof being expressed according to
the scale of values from 0 (growth equal to the one of
the check) to 4 (full stop of the growth or complete
killing of the plants).
9 _
