Note: Descriptions are shown in the official language in which they were submitted.
RS(984)JGC
~05S039
NOVEL TRIORGANOTIN C~MPOUNDS ~ND METHOD
FOR COMBATING FUNGI AND MITES USING SAME
This invention relates to a method for ~electively
controlling fungi and mites using dicyclohexylphenyltin
compounds. The organisms against which the compounds are
effective are responsible for a considerable portion of
the annual damage to agricultural crops, particularly
tomatoes, apples, and rice. Over the years fungi and mites
have deveLoped a resistance to many chemicals which had
previously been effective in combating them. The development
of resistant strains has mandated a search for new miticides
and fungicides~ Some triorganotin compounds effectively
eontrol these pets; however, with fe~ exceptions this
class of compounds is relatively non-selective when
applied to desirable plant crops, in that while the organism
attacking the plant may be controlled, the plant itself is
often killed or severely damaged.
~OSS~
It has now been found that dicyclohexylphenyltin derivatives of the
general formulae
~ R2~ ~
~ X and ~ ~ 3J Y
effectively control fungi and mites yet do not substantially damage plants
to which efficacious amounts of these compounds are applied. In the foregoing
formulae, each Rl and R2 is individually selected from the group consisting
of hydrogen atoms and linear and branched alkyl radicals containing between
land 8 carbon ato~s, X represents a radical selected from the group consisting
of chlorine, bromine, fluorine, hydroxyl, carboxylate, phenoxy, alkoxy
(-oR3), and mercaptide (-SR3), wherein R3 represents an alkyl radical contain-
ing between 1 and 12 carbon atoms, inclusive and Y is an oxygen, sulfur, orsulfate radical.
In particular, the invention relates to a dicyclohexylphenyltin
compound of the general formula
~Z OT ~ Y
wherein each Rl and R2 is individually selected from the group consisting
of hydrogen atoms and linear and branched alkyl radicals containing between
1 and 8 carbon atoms, Y is selected from the group consisting of oxygen,
sulfur and sulfate radicals and Z represents a monovalent radical selected
from the group consisting of fluorine, hydroxyl, carboxylate, phenoxy, alk-
koxy (-oR3) and mercaptide (-SR3), wherein R3 represents an alkyl radical
2Q containing between 1 and 12 carbon atoms, inclusive.
The invention also provides a method for controlling fungi and mites
~ - 2 -
~?
j
lOS'~039
which comprises contacting said organism with a compound of the formula
R5~
-X or ~ ~ Sn ~ Y
lR52~ \ R~b / 2
wherein each R and R is individually selected from the group consisting
of hydrogen atoms and linear and branched alkyl radicals containing between
1 and 8 carbon atoms, X represents a monovalent radical selected from the
group consisting of chlorine, bromine, fluorine, hydroxyl, carboxylate,
phenoxy, alkoxy (-oR3) and mercaptide (-SR3), wherein R3 represents an
alkyl radical containing between 1 and 12 carbon atoms, inclusive and Y
is selected from the group consisting of oxygen, sulfur and sulfate radicals.
- 2a -
1055039
DETAIL~D DESCRIPTION OF THE INVENTION
The dicyclohexylphenyltin compounds of this invention
wherein X is bromine are conveniently prepared by reacting the
appropriate dicyclohe~yldiphenyltin compound with bromine. This
is a well known type of reaction and has been described in the
chemical literature for the preparation of numerous other
triorganotin derivatives.
Tetraorganotin compounds which can be employed
to prepare the corresponding triorganotin bromide exhibit the
generic formula
~ ~ Sn ~
Preferably the tetraorganotin compound is dissolved in a suitable
solvent or mixture of solvents ~o which a solution of bromine is
gradually added. Suitable solvents include alcohols containing
between 1 and 8 carbon atoms and Liquid halogenated hydrocarbons.
Any compound which is a liquid at the reaction temperature and
does not react with bromine or the tetraorganotin compound can
be employed as a solvent for the tetraorganotin compound. The
temperature of the reaction mixture is maintained below ambient
temperature, preferably between -30 and 25C., during addition
of the bromine to control the degree of hydrocarbon radical
cleavage, and maximize the yield of the desired product. The
reaction is believed to proceed in accordance with the follow-
ing form~la:
~ ~ (R, ~ , Sn~nr~ l R, ~ Br+ ~ ~ r
The resultant dicyclohexylphenyltin bromide may be a liquid
or solid at ambient temperature depending upon the substituents
P~ and R and can readily be converted to other derivatives
such as the oxide or hydroxide, acetate, and sulfate using kno~n
reactions. The desired anionic radical can be introduced by
reacting the correspondin~ bromide, oxide, or hydroxide with
the reagent indicated in the following table.
~L055039
ORG~NOTIN DERIVAl'IVE ~ REAGENT ~ DESIRED PRODUCT
Bromide Carboxylic acid ~ carboxylate,
acid acceptor~ e.g. e.g. acetate
pyridine
" alkali metal ~alt of "
carboxylic acid
" aqueous solution of hydroxide or
alkali metal hydroxide oxide
S " alkali metal alkoxide alkoxide
or alcohol I acid
acceptor
" alkali metal phenoxide phenoxide
or phenol ~ acid
acceptor
" potas~ium fLuoride or fluoride
hydrofluoric acid
" alkali metal sulfide ~ul~ide
" alkali metal sulfate sulfate
" mercaptan + acid mercap~ide
acceptor
Oxide (or hydroxide) carboxylic acid or carboxylate
anhydride
" alcohol (or phenol) alkoxide (or
pheno~ide)
It hydrofluoric acid fluoride
" dilute (10-25 weight sulfate
%) aqueous 6ulfuric acid
" hydrogen 6ulfide ~ulfide
" alkyl or aryl mercaptan mercaptide
" aqueous hydrochloric chloride
acid
lC~55039
The identity of the substituents R and R and the
conditions under which the compound i8 stored will determine
whether the bis(triorganotin) oxide or the corresponding
triorganotin hydroxide is the more stable compound.
The reaction conditions such as preferred solvents,
temperatureæ and reaction times for preparing the derivatives
summarized in the preceeding table are known in the art and,
therefore, do not require a detailed description in the present
specification. A comprehensive treatment of this subject
matter is contained in an article by R. K. Ingham et al~ that
appeared in the October, 1960 issue of CHEMICAL REVIEWS
(P.P. 459-539).
The dicyclohexylphenyltin compounds are liquids
or solid materials at ambient temperature, depending upon the
type of substituents represented by Rl, R , X and Y.
Dicyclohexylphenyltin compounds effectively combat
undesirable mites and fungi without significantly damaging
the plants to which the compounds are applied. A single
application of these compounds can provide re6idual and extended
control of fungi and mites for a considerable period of time,
the duration of which i6 dependent to some extent upon
mechPnical and biological influences, including weather, but
is sometimes as long as several mon~hs.
I~ preparing compositions for application to
plantsJthe tin compound is often augmented or modified by
combining it with one or more commonly employed pesticide
~055039
additives or adjuvants including organic ~ol~ents, water or
other liquid carriers, surface active dispersing ag~nts or
particulate and finely comminuted or divided solid carriers.
Depending upon the concentration of the tin compound in
these compositions, they can be employed either directly to
control the organisms or as concentrates which are subsequently
diluted with one or more additional inert carriers to produce
the ultimate treating compositions. In compositions to be
employed as concentrates, the dicyclohexylphenyltin compound
can be present at a concentration of from about 5 to about 98~
by weight. Baits, attractants and the like can also be included
for combating mites. Other biologically active agents that
are chemically compatible with the present tin compounds can
also be added.
The optimum concentration of tin compounds to
be employed as toxicant in a composition for application to
the organism directly or by employing its habitat or food as
carrier, may vary pro~ided that the organism is contacted
with an effective dose of the toxicant. The actual weight of
compound constituting an effective dose is primarily dependent
upon the susceptibility of a particular organism to the tin
compound. Good control of bean mildew is obtained with liquid
or dust compositions containing O.OOO~ percen~ or less weight of
toxicant in the formulation as it is applied to the plant.
Compositions containing as high as 90 percen~ by weight of toxicant
an sometimes be employed in the treatment of a mite-infested
environment.
i~O55039
In the preparation of dust compositions, the
dicycLohexylphenyltin compound can be blended with many commonly
employed finely divided solids, such as fuller~s earth,
attapulgite, bentonite, pyrophyllite, vermiculite, diatomaceous
earth, talc, chalk, gypsum, wood flour, and the like. In such
operations, the finely divided carrier is ground or mixed
with the toxicant or wet~ed with a dispersion of the toxicant
in a volatile li~uid. Depending upon the proportions of
ingredients, these compositions can be employed as concentrates
and subsequently diluted with additional solid of the types
indica~ed hereinbefore, to obtain the desired amount of active
ingredient in a comminuted composition adapted for the control
of pests. Also~ su~h concentr~te dust compositions can be
incorporated in intimate admixture with surface active
dispersing agents such as ionic and non-ionic emulsifying or
dispersing agents to form spray concentrates. Such concentrates
are readily disper~ible in liquid carriers to form spray com-
positions or liquid formulations containing the toxicants in
any desired amount. The choice of surface active agent and
amount thereof employed are determined by the ability of the
agent to facilitate the dispersing of the concentrate in the
liquid carrier to produce the desired liquid composition.
Suitable liquid carriers include water, methanol, ethanol,
isopropanol, methyl ethyl ketone, acetone, methylene
chloride, chlorobenzene~ toluene, xylene, and petroleum
distillates. Among the preferred petroleum distillates
~ 0 5 5~ 3 9
are those boiling almost entirely ~mder 400F. at atmospheric
pressure and havin~ a flash point above about 80F.
Alternatively, the dicyclohe~ylphenyltin compound can
be dissolved in a suitable water-immiscible organic liquid and
a surface active dispersing agent to produce emulsifiable
concentrates which may be further diluted with water and oil
to form spray mixtures in the form of oil-in-water emulsions.
In such compositions, the carrier comprises an aqueous
emulsion, i.e. a mixture of water-immiscible solvent, emulsify-
ing agent and water. Preferred dispersing agents which may be
employed in these compositions are oil soluble and include the
concensation products of alkylene oxideæ with phenols and
organic and inorganic acid~, polyoxyethylene derivatives of
sorbitan esters~ aLkylarylsulfonates, complex ether alcohols,
mahogany soaps and the like. Suitable organic liquids to be
employed in the compositions include petroleum distillates,
hexanol, liquid halohydrocarbons and synthetic organic oils.
m e surface active dispersing agents are usually employed in
the liquid dispersions and aqueous emulsions in the amount
of from about 1 to about 20 percent by weight of the combined
weight of the di~persing agent and the active toxicant.
When operating in accordance with the present invention,
the dicyclohexylphenyltin compound or a composition containing
the compound can be applied directly to the undesirable organism
when mites are being controlled, or to their habitat or food
1055039
in an~ convenient fashion, i.e. by means of hand dusters
or sprayers or by simple mixing with the food to be ingested
by the mites. Applications to the foliage of plant~ i8
conveniently carried out using power dusters, boom sprayers
and spray dusters. t~hen employed in this manner the composi -
tions should not contain any significant amounts of phytotoxic
diluents. In large scale operations, dusts or Low volume sprays
may be applied from an aircraft.
- The following examples represent the best embodiments of
the present invention now kno~n, and tell how to practice them.
EXAMPLE 1
This example discloses the preparation of dicyclohexyl-
phenyl tin bromide.
A &olution containing 171.g g~ (0.5 moLe) of diphenyltin
dichloride and 500 c.c. of toluene was added gradually o~er
1.25 hours to 1 liter of mixture containing 1.5 moles of
cyclohexyl magnesium chloride and tetrahydrofuran as the
diluent. The reaction vessel was equipped with a mechanically
driven agitator, water-cooled reflux condenser, addition
funnel, thermometer and nitrogen inlet. The temperatures
of the reaction mixture gradually increased to 61C. during
the addition~following which a 250 c.c. portion of toluene
was added.
1055039
The reaction mixture was heated at the boiling
point for 1.5 hours, then cooled to ambient temperature, at
which time n solution containing 55 gO of citric acid and 400 c.c
of water was added. The organic phase was separated and dried
by combining it with a quantity of anhydrous magnesium sulfate,
after which the liquid phase was concentrated under reduced
pressure until it appeared turbid. The addition of 250 c.c.
of methanol yielded a precipitate which was isolated and washed
with-methanol. The dried solid weighed 207.5 g. (94~5% of
theoretical yield)0 The solid wa~ found to contain 27.27% by
weight of tin. The theoretical tin content of dicyclohexyldi-
phenyl tin is 27.02%.
A solution containing 16.0 g. (0.1 mole) bromine,
S0 c.c. methanol, and 50 c.c. chloroform was added drop-wise
to a solution containing 43.9 g. (0.1 mole) of dicyclohexyl-
diphenyltin , S0 c.c. methanol and 110 c.c. chlorofonm. The
addition required 1.75 hour6, during which time the temperature
of the reaction mixture was maintained at 0C. Each drop of
bromine wa~ added onLy after the color imparted by the pre-
ceding drop had disappeared. Following completion of the addition
the resultant clear solution wa~ concentrated under reduced
pres6ure. The colorless liquid residue w~ighed 51.3 g. and
exhibited a refractive index (ND ) of 1.5826. The unreacted
dicyclohexyldiphenyltin precipitated following the addition
of 150 c.c. of methanol to the crude product. The solid
.
1055039
weighed 4.0 grams. The methanol was removed from the liquid
phase under reduced pressure. The liquid was then treated
with gaseous ammonia to precipitate dicyclohexyltin dibromide
as the ammoni~ complex, and the resultant ~olid removed. The
remaining liquid was concentrated under reduced pres~ure to
yield 22.2 g. of a liquid which upon analysis by vapor phase
chromatography was found to contain 96% by weight of dicyclo-
hexylphenyltin bromide.
EXAMPLE 2 - Preparation of Dicyclohexglphenyltin Hydroxide
Dicyclohexylphenyltin hydroxide was prepared by
adding a solution containing 3.0 g. (0.075 mole) sodium hydroxide
and 25 c.c. water to a solution containing 20.7 g. (0.047 mole)
dicyclohexylphenyltin bromide and 205 c.c. methanol. Following
completion of the addition the resultant mixture was heated at
the boiling point for one hour, then allowed to cool to ambient
temperature with agitation. A 200 c.c. portion of water wa~
added to the resultanL mixture, which contained a white solid
precipitate. The solid material was isolated, washed with
deionized water until free of bromide and then dried in a
ciculating air oven. The product weighed 16~7 g. (93.8% of
theoretical yield) and was found to contain 31.65 % by weight
of tin. The calculated tin content for the hydroxide is 31.31%.
1055039
BIO~OGIC~L ~CTIVI'~Y OF DICYCLOHEXYLP~ENYL TIN DERIV~TIVES
_ . . . ,, . --. - - _ ,
1. General Evaluation Methods
Dicyclohexylphenyltin hydroxide was evaluated
in the form of sprayable compositionR prepared by dissolving or
dispersing the compound in a 90/10 weight ratio water/acetone
mixture containing a small amount of a non-ionic surfactant.
The resultant stock solution or dispersion was then diluted
using a water-sur~actant mixture to obtain ~he desired con-
centration of tin compound while maintaining ~he surfactant
concentration at 100 parts per million (ppm). Samples which
proved difficult to emulsify were homogenized using a colloid
mill or tissue homogenizer.
2. Evaluation of the Effectiveness of Dicyclohexylphenyltin
~ydroxide Against Specific Organisms.
The efficacy of the triorganotin compounds of
this invention as fungicides and ~iticides was investigated
and the results are summarized in the following section. The
test organisms employed were powdery bean mildew, apple scab
and the two-spotted spider mite.
The rating system employed to determine control
of the organi~ms was based on a numerical scale wherein a
rating of 10 indicated 100% control (no 3urviving organisms)
and a rating of O indicated no control, i.e. the plant was
heavily infested with the organism. The control rating employed
for the bean mildew and apple scab is R function of the fraction
of total leaf area which i8 unaffected by these fungi.
.,_, ,~ ,, .
1 1055039
Ao Powd~ry Bean Mildew
Tender ~reen bean plants with fully expanded
primary leaves are inoculated with spores of the powdery
mildew fungus (erysiphe polygoni) 48 hours prior to the ap-
¦ plication of dicyclohexylphenyltin hydroxide. The tin
¦ compound is applied at the concentrations indicated in the
¦ following table by placing the plants on a revolving turntable
~ and spraying them with a formulation containing the
¦ triorganotin compound. I~hen the spray deposit dries,
¦ the plants are placed in a greenhouse for 28 days~ during
¦ which time the amount of mildew on the primary le2ves i8
¦ rated at intervals of 7 days following the spraying. Untreated
plants serve as controls, which exhibit a rating of 1.0 or less.
¦ 'rhe formulations tested contained 100, 20, and 4 parts per mil-
~ lion ~p.p.m.~ of dicyclohexylphenyltin hydroxide.
151 CONCENTRATION D.~YS FOLLOWING
(P.p-m-? INITIAL SPRAYING CONTROL RATING
100 7 LO.O
14 10.0
21 10.0
28 10 0
l , _ _
1 20 7 10.0
14 9.8
21 9-3
28 8 3
. . . , ,
1 4 7 g.5
1 14 5.9
21 4.0
1 28 1.9
I _.
1055039
None o~ the formulations tested were phytotoxic to
plants.
B. Apple Scab
Frozen apple leave~ which were infested with conidia
spores were soaked in cool water for about 30 minutes, fol-
lowing which the liquid phase was filtered through a single
layer of cheesecloth. A nu~ber of apple seedlings in the
fifth leaf stage were sprayed with the water containing the
dispersed conidia spores. The seedlings were stored in a
high humidity environment [relative humidity (R.H.) = 100%]
at ambient temperature for two days, after which they were
stored at a temperature of 24~3C. for 6even days, then in
the high humidity environment for between one and two days,
and finally at 24~3C. for 10 to 15 days, during which time
the infested leaves were harves~ed. The leaves were extracted
with cool water to prepare a stock solution which when viewed
under a microscope at 100 X magnification exhibited a field
containing not Less than 20 conidia spores.
The plants to be tested were sprayed with a liquid
fo~mulation containing dicyclohexylphenyltin hydroxide.
The formulation was prepared as previously described. After
the solvent had evaporated the leaves were sprayed with
the suspen~ion of conidia spores prepared as described in
the preceeding paragraph. The plants were then pLaced in
a high humidity (100% R.H.) environment at smbient
temperature for two days, after which they were stored
under conditions o~ ambient humidity and a $emperature of
11 1055039
24+3C. until evidence oE apple scab was observed on the
untreated control, as indicatcd by hrownish Lesions on the
leaves. The resul~s of the test are summarized below.
Concentration of Control
Or~,anotin ComT~ound (p.p.m.) Ratina
250 99
9,9
12.5 9,1
C. Two-spotted S~ider Mite
Bean plants were sprayed with formulations contain-
ing a dispersed form of dicyclohexylphenyltin hydroxide at
concentrations of 50 and 200 p.p.m.. The ~article
size of the dispersion was between 50 and 100 microns. Between
one and three days following the spraying a number of nymph stage
and adult spider mites were transferred onto the upper surface
of the plant leaves. The plants remained undisturbed at 24~3C.
for between 12 and 14 days following exposure to the mites,
at which time the percentages of dead nymphs and adult mites
were observed and the results recorded as the initial controL
test. The long-term effect of the tin compound was evaluated
by placing a new supply of adult and nymph stage mites onto the
bean plant leaves following the initial observations. No
additional triorganotin compound was applied. The percentages
of dead nymph and adult mites were again observed between
21 and 30 days following the initial application of the spider
mites, and the results recorded as the residual control test.
1 055039
CONCENT~TION OF TIN INITIAL RESIDU~L
OMPOUND IN SPRAY (P.P.M. ) CO~TROL CONTROL
. .. .
200 10 (A); 10 (N) 10 (A); 9.9 (N)
10 (A); 9.9 (N) 10 (A); 9.9 (N)
A = adult mites; N - nymph ~tage mites
Although all of the compounds employed to determine
biological activity were triorgano~in hydroxides, other
derivatives including fluorides, chlorides, brom~des, carboxyl-
ates, mercaptides, alkoxides, phenoxide~, ~ulfide~ and sulfates
are expected to be at leas~ equally efficaciou~ in combating
fungi and mites since it ha~ been shown that the anionic radioal
of the present triorganotin compound~, represented by X and Y
in the foregoing generic formulae, have little, it any, effect
of the degree of biological activity exhibited b~ the co~pound
unless the anion it~elf possesses significant biological
activity.
