CA1097651A - Triorganotin compounds and method for combatting fungi and insects using same - Google Patents

Abstract

Abstract of the Disclosure - Novel sterically hindered triorganotin compounds of the general formula or effectively combat fungi and insects, particularly mites, when applied to plants that are susceptible to attack by these organisms. The present compounds are particularly advan-tageous in that they are considerably less phytotoxic than homologous triorganotin compounds wherein the hydrocarbon radicals are linear and contain from 4 to 6 carbon atoms, such as n-butyl and n-hexyl radicals. In the foregoing formulae R1 is methyl or ethyl, R2 is hydrogen, methyl or ethyl and n is 0, 1 or 2, with the proviso that each of the three hydro-carbon radicals bonded to the tin atom contains from 6 to 10 carbon atoms; X is selected from the group consisting of chlorine, bromine, fluorine, hydroxyl, nitrate, cyanate, thiocyanate, carbamate, thiocarbamate, . , , , phenoxy, alkoxy (-OR4), dithiocarbamoyl , mercaptide (-SR?) and dialkylditihiophosphate wherein R?

represents alkyl containing from 1 to 12 carbon atoms or wherein Z is hydrogen, halogen, 1-3 carbon alkyl, 1-3 carbon alkoxy or nitro (-NO2), R4 is alkyl containing from 1 to 12 carbon atoms, Y is , wherein m is an integer from 2 to 10, inclusive,

Description

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~~ This invention relates to a method for selectively controlling fungi and insects, especially mites, using a specified class of triorganotin compounds. The organisms I against which the compounds are effective are responsible for I a eonsiderable portion of the annual damage to agricultural .
crops. Many tri-n-alkyltin compounds, partieularly tri-n-butyltin and tri-n-amYltin derivatives may effectively eontrol these organismsg however, these eompounds are relatively non-selective toward both agrieultural and I! i ll decorative plants in that ~^ThiLe the fungus or insect attacking .
the plant may be eontrolled, the plant to whieh the compound i6 applled ls ' e~ntly kllled or severely damaged.

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l l i !I j It has now been ~ound that certain noYel ste~ically hindered triorganotin compounds of the general formula ~ j ~R,~CH:~nC-C~ SnY or ~ CH3~CR,~nC-C~, 1 9n effectively control fungi and insects yet are relatively harmless toward plants to whlch efficacious amounts of these compounds are applied. In the foregoing formulae R is methyl ~ -or ethyl, R is hydrogen, methyl or ethyl and n is O, l or 2, with the proviso that each of the three hydrocarbon radicals bonded to the tin atom contains from 6 to lO carbon atoms, X is ~lO s~lected from the group consisting of chlorine, bromine, fluorine, hydroxyl, nitrate, cyanate, thiocyanate, carbamate, thiocarbamate, !' O O 1 -OCR , -O-C ~ ~ -NH2, ~ ~ ~ Nj HzN ~ N ~ S ~~ ' ~ N~ l phen~xy, alkoxy (-OR ), dit/io~rbamoyl (SCN < ~ , mercaptld-~ (-SR ) and dlalkyldithlophosphate (S ~ ~ whereln R

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represents alkyl containing from 1 to 12 carbon atoms or ~ wherein Z is hydrogeln, halogen, 1-3 carbon alkyl, 1-3 carbon alkoxy or nitro (-NO2), R is alkyl containin~

from 1 to 12 carbon atoms, Y is -OC(CH2)mC-O- , wherein m 1s an integer ~rom 2 to 10, inclusive, -OC ~ CO , oxygen, sulfur, sulfate, phosphate, or carbonate and a represents the valence of Y and is the integer 2 or 3.

`Çi5:1 The three hydrocarbon radicals Or the present organotin compounds contain a secondary or tertiary carbon atom that is separated from the tin atom by a methylene (-CH~
group. The remaining valences of the secondary or tertiar~ ¦
carbon atom are satisfied by at least one methyl or ethyl radical and an alkylene radical containing from 1 to 3 carbon atoms, such`tha'c the total number of carbon atoms present on ; each of the three hydrocarbon radicals bonded to the tin atom ~ is from 6 to 10. The preferred hydrocarbon radicals are

2,2-dimethylbutyl and 2-ethylbutyl.
Compounds of the foregoing formula wherein X represents chlorineg bromine or iodine are conveniently prepared by ,, . i reacting a tetraorganotin compound of the general formula , 1 ' - !1 1 2 CH3(CH2)nC-CH2- - SnR wherein P. and R are as previously R
~., . ~1 - 3 ~.
defined and R represents a lower alkyl radical that preferably , . i contains from 1 to 4 carbon atoms~ with an equimolar amount of a stannic halide. During the reaction the lower alkyl i1 5 radicaL R is replaced by a halogen atom ~rom the stannic '' halide. The reactions involved in preparing the present , triorganotin halides can be represented by the following 3i R
equation-s wherein A is CH3(CH2)nC_CHz- and Z , Z and Z are R
j3 indivldually selected ~rom the group consisting o~ chlorine, " bromine and iodlne.
~ _4_ 5 ~ i 2 ~ 1 a ¦, 3AMgZ ~ R SnZg ~ A 3 SnR + 3MgZ Z

3 3 A 3 SnR t SnZ 4 ~ A 3 SnZ ~ R SnZ~
The by-product of the second reactlon, R SnZ3, I can be recycled to prepare a second portion of the tetra-j organotin compound by reaction with the appropriate organo-1' magnesium halide, AMgZ . Specific procedures for preparing 1' 1, representative compounds are described in the accompanying examples.
' The ;~forementioned alkyltin trihalide R SnZ3 can, in turn, be prepared by reacting the corresponding alkyl halide, R Z , with a stannous halide SnZ 2 as described in United States Patent ~,340,283, the pertinent sections of which are hereby incorporated by reference.
The reaction between the stannic halide and tetra-organotin compound should be performed under anhydrous ; conditions at temperatures from about -25 to 80C., preferably from ~25 to 80C., in a liquid hydrocarbon solvent. Preferred solvents include pentane, hexane and cyclohexane.
; Preferably the stannic halide is dissolved in an organic solvent and the resultant solution added dropwise to a second solution containing the tetraor~anotin compound in the same solvent. The temperature of the reaction mixture is i, preferably maintained below about 40C. during the addition, ~ which requires about one hour, after which the mixture is 25 i heated to a temperature from 35 to 80C. Preferably the temperature employed is the reflux temperature o~ the reactlon mixture. Heating is continued for from about 15 to 60 minutes 1 ~
to en~ure complete reactlon. The reactlon mixture 1~ then ~5~

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allowed to cool to ambient temperature, and extracted with one or more portions Or water or a dilute aqueous mineral acld solution. The monoorganotin trihalide, R SnZ 3 ~ iS soluble in the aqueous phase of the reaction mixture while the desired product remains in the organic phase, and is readily isolated by boiling away the hydrocarbon solvent. No further purification is usually required, however the product can be distilled or recrys tallized if desired. The organic layer is preferably freed of an~ dissolved water ~ollowing the extracting step. Any of the ' conventional chemical dehydrating agents are suitable, provided ¦
that they will not react with either the triorganotin halide or ¦
, the hydrocarbon solvent. Preferred drying agents include ¦l anhydrous magnesium sulfateg anhydrous sodium sulfate and !l anhydrous calcium sulfate.
1 Alternat~vely~ the present triorganotin bromides can be prepared by the gradual addition of bromine to a solution ~' containing the corresponding tetraorganotin compound of the formula A4Sn, wherein A represents a sterically hindered alkyl ~1i group as di~closed in the preceding specification. The 1¦ tetraorganotin compound is, in turn, prepared by reacting the ~! corresponding organomagnesium halide, AMgZ, with a stannic i ¦ halide in a molar ratio of 4:1g respectively.
¦¦ The present triorganotin halides are solids or liquids at ambient temperature. The halideæ can readily be converted ~ to other deri~atives such as the oxide, acetate and sul~ate using known reactions. The desired anionic radical can be introduced by reacting the corresponding triorganotin halide, hydroxide or bis(triorganotin) oxide with the reagent indicated ln the follow~ng table.

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ORGANOTIN DERIVATIVE ~ REAGENT DESIRED
PRODUCT
Chloride, Bromide Carboxylic acld + carbo xylate, or Iodide acid acceptor, e.g. e.g. acetate an amine " alkali metal salt o~
a carboxyllc acid " aqueous solution of oxide (or , alkali metal hydroxide hydroxide) " alkali metal alkoxide alkoxide or alcohol ~ acid acceptor (e.g. an amine) " alkali metal phenoxide phenoxide or phenol ~ acid acceptor " potassium fluoride or fluoride hydrofluoric acid " alkali metal sulfide sulfide " alkali metal sulfate sulfa~e " mercaptan + acid mercaptide acceptor " alkali metal cyanate cyanate " alkali metal thiocyanate thiocyanate " alkali metal thiocarbamate thiocarbamate tl alkali metal dithiocarbamate dithlocarbamate ~ ~J7 ~ ~ ~

ORGANOTIN DERIVATIVE ~ REAGENT D~SIRED PRODUCT

Chloride, ~romide phosphoric acld phosphate or Iodide or alkall metal phosphate !.' alkali metal dialkyldithio-dialkyldi~hio- pho~phate phosphate Oxide or Hydroxide carboxylic acid or carboxylate . anhydride " alcohol (or phenol) alkoxide tor phenoxide) . " hydrofluoric acid fluoride dilute t10-25 weight sulfate %) aqueous sulfuric " hydrogen sulflde sulfide " alkyl or aryl mercaptide mercaptan " carbon dioxide carbonate Hydroxide heat to remove oxide . water . .
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The reaction conditions such as pre,erred solvents, temperatures and reaction times for preparing the derivatives summarlzed in the preceding table are known in the ar~ and, therefore, do not require a detailed description in the present specification. A comprehensive treatment of this sub~ect matter together with numerous literature references is contained in an article by R. K. Ingham et al. that appeared in the October~ 1960 issue of CHEMICAL REVIEWS (ppO 459-539).
The aforementioned derivatives may be liquids or solids at ambient temperature~ depending upon the type of substituents represented by X or Y.
The present sterically hindered tri-alkyl.tin compounds effectively control many types of undesirable . fungi and insects, particularly mites, when applied to living plants that are susceptible to infes~ations of these organisms.
The combination of fun~icidal and miticidal activity is not : common for a single organotin compound. A slngle application : of these compounds to living plants or other substrates provid~s :~. residual and extended control of many varieties o~ ~ung~ and insects for a considerable period of time, the duration of whl~Gh is dependent to some extent upon mechanioal and biologioal in~luences~ including weather. Formulatlsn3 containing the present organotin compounds can be applied ; directly to the organism to be controlled or to environments that w~ bsequent~y ie in~ested with the organism.

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In preparing compositions ~or application to plants the organotln compound is often augmented or modified by combining it with one or more commonly employed pesticide add-ltives or ad~uvants includlng organic solvents, water or other liquid carriers, surfactants to aid in dispersing or emulsifying the organotin compound and finely comminuted solid carriers. Depending upon the concentration of triorganotin compound in these compositions, they can be employed either without additional d~luents or as liquid concentrates which are subsequently diluted with one or more additional inert liquids to produce the ultimate treating compositions. In compositions employed as concen-trates, the triorganotin compound can be present at concentrations of from about 5 to about 98~ by weight. Other biologically active agents that are chemically compatlble with the present triorganotin compounds can also be added.
The optlmum effective concentratlon of tln compound to be employed as toxicant in a composition is dependant upon whethe~ the organism is contacted with or, as ln the case of insects, lngests the toxicant. The actual weight of compouncl consti~uting an effective dose is primarily dependent upon the suscept~bility o~ ~he particular organism to a g~ven triorganoti n compound. For control o~ insects5 good results are obtainea ; with liquid or dust compositions conta~ning as little as one part per million by weight o~ toxicant~ Compositions contain-ing up to 90 percént by weight of toxicant can be employed to treat a heavily infested area.

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In the preparatlon o~ dust compositions, the organo-tln compound can be blended with many commonly employed finely divided solid carriers such as fuller'~ earth, attapulgite, bentonite, pyrophylllte~ vermiculite, diatomaceou~ earth3 talc, chalk~ gypsum and wood fiour. The carrier, usually ln a f$nely divided form, ~s ground or mixed wlth the toxicant or wetted with a dispersion o~ the toxicant in a volatile liquld. Depending upon the relati~e proportions o~ ~oxicant and carrler, these composltions can be employed as concentrates that are subsequently diluted with additional solid carrier to obtain the desired amount o~ active ingredlent~
Alternatively~ such concentrate dust compositions can be employed in combination with various known anionic, cationic or non-ionic sur~actants as emulsifying or disperslng agent~ to ~orm spray concentrates. Such concentrates are readily disper~ible in liquid carriers ~o form spray compositions or .
liquid formulations contalning the toxicants in any de~ired amount. The cholce and concentration of ~ur~actant are determined by khe ability Or the material ko facilitate the dispersing of the concentrate in ~he liquid carrier to produoe the deslred llquid composition~ Suitable l~quid carriers include water, methanol, ethanol~ isopropanol, methyl ethyl ketone, acetone, methylene chloride, chlorobenzene, toluene, ; xylene and petroleum di~tillates1 Among the preferred petrolleum distlllate6 are ~hose bolling undsr 400F. at atmospheric pressure and having a flash point above about 80F.;

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. ' ', , ~7&~1 ~iquid comp~o~ltions can also be prepared by dissolving one of the present triorganotin compound~ in a mixture containing a water-immisclble organic liquid and a sur~ace active dispersing agent. The resultant emulsiflable concentrate is then f`urther diluted with water and an oil to ~orm spray mix~res in the form of oil-~.n water emulsions.
In such compo~itionrs, the carrier comprlses an aqueou~
emul~ion, l.e. a mixture o~ water~immisclble solvent, emulsl~ying agent and water. Pre~erred dlspersing agent~ for these compositicns are oil-soluble and lnclude the condensation products o~ alkylene oxides with phenols and organic or inorganic acids~ polyoxyethylene derivatives of sorbitan es~ers, alkylarylsulfonates, complex ether alcohols, mahogany soaps and the li~e. Su~table organic liquid~ to be 15 ~ employed in the compos1tlons lnclude petroleum dlstlllates, ~exanol, liquid halohydrocarbons and synthetic organic oils.
The sur~ace active dispersing agents are usually employed in the liquid dlsperslons and aqueous emulsions in the amount o~
from about i ko about 20 percent by weight o~ the combined -welght o~ the disperslng agent and the active toxlcant~
When operatin~ ln accordance with the pre~ent inventlon, the organotin compound or a composition containin~
~he co~pound can be applied directly onto the organism to be controlled or to the site to be protected~ par~icularly plant~
and trees. Application to ~he ~oliage of plants is con~eniently carrled out using power dusters, boom sprayer~
and spra~ du~ter~;`~When employed ~n this manner the composltion ~hould not contain any signl~icant amount~ of phytotQxic dlluents. In large scale operations, du6ts or low volume spray~ may be applied ~rom an alr~ra~t.

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la~7~;sl 1 The following examples represent preferred embodiments of the present compounds and their use as fungicldes and insecticides, and are,not intended to limit the scope of the accompanying claims. All parts~ percentages and ratios are by weight unless otherwise specified.

¦ - EXAMPLES

, EXAMPLE 1 - Preparation of Tri(2-ethylbutyl)tin Bromlde and Derivatives Thereof A. Preparation of Tetra(2-ethylbutyl~tin l To 24.3 g. (l g. atom) of magnesium chips heated to ~l a temperature Or 40C. under a nitrogen atmosphere was added ,~, a 25 cc. portion of a solution containing 165 g. (l mole) of l-bromo-2-ethylbutane dissolved in 450 cc. of anhydrous tetrahydrofuran. The reaction was initiated using a few drops ,, of ethylene dibromide. The remaining portion of the 1-bromo-, 2-ethylbutane solution was gradually added during a period ~, of 1.5 hours. The heat generated was sufficlent to maintain the reaction mixture at the boiling point. External heat was ~, i~ applied for an additional hour, ~ollowing completion of the ~5 addition. The reaction mixture was allowed to cool to ambient ~i temperature and remain at this temperature for about one hour, I during which time stirring of the mixture was continued. At ¦ ~he end of this period all of the magnesium appeared to have reacted, A 200 cc. portion of this solution containing 0.4 ¦ mole of 2-ethylbutyl magnesium bromide was placed ln a reactor , under a nitrogen atmosphere. To this solutlon was gradually added a solution containing 26 g. (0.1 mole) o~ stannic chloride dissolved ln 150 cc. of benzene. The addition required : I

i5:1 2 hours, during which time the temperature of the reaction mixture was maintained below 40C. Following completion of the addition the reaction mixture was hea~ed to the boiling i point for 1.5 hours, then allowed to cool to ambient ¦, temperature. To the resultant mixture was added a solution containing 250 cc. water and 25 g. of citric acid. The organic I
¦ phase of the resultant two phase liquid was separated and the water present therein removed using a portion of anhydrous magnesium sulfate, which was subsequently removed by filtration. The solvent was evaporated under reduced pressure to yield 43.1 g. (94% yield) of a liquid, tetra(2-ethylbutyl)tin.
The product was found to contain 25.90~ tin. The calculated value for tetra(2-ethylbutyl)tin is 25.86%.
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. Cleava~e o~ Tetra~2-ethylbutyl)tin to Tri(2-eth~lbutyl)tln Bromide A 45.9 g. (O.l mole) portlon of tetra(2-ethyl-butyl)tin prepared as described in part A of this example was dissolved in a mixture of 200 cc. chloroform and 200 cc.
methanol and cooled to 0C. To this solution was added a solutlon containing 16.~0 g. (0.2 g. atom) of bromine and 100 cc.
i of the a~orementioned chloroform-methanol mixture. The I addition required 3 hours, following which the result?-nt 1 mixture was stirred for 0.25 hours while being cooled to QC.
! The sol~ent was then removed under reduced pressure to yield ii 46.6 g. of a yellow llquidO The product was found to contaln , 25.14% tin and 15.19% bromine. The calculated values for I tri(2-ethylbutyl)tin bromide are 26.14% tin and 17.60% bromine. ¦

il Bis~tri(2-ethylbutyl)tin] oxide was prepared by ! adding a solution o~ the corresponding bromide (45.4 g. of the i bromide in 100 cc. of methanol) to a solution containing ¦l 8 g. of sodium hydroxide, 50 cc. water and 50 cc. methanol.
I The addition was gradual and required 0.25 hour, at which time j the mixture was heated a~ the boiling point for 20 mlnutes, i then allowed to cool to ambient temperature. A 300 cc.
portion of diethyl ether was then added, followed by 400 cc.
water. The organic phase of the resultant 2-phase liquid was I isolated and combined wi~h a portion o~ anhydrous magnesium I sul~ate to remove traces Or wa~er The aqueous p~ase was discarded. The ether presen~ ~n ~he organic layer was remoYed ko yield 36.5 g. of a clear yellow liquid exhlbitlng a re-fract~ve index (n D? of 1.4~15. The liquld was ~ound to contain 30.10% tin. The calculated tln content ~or bisCtrl(2-3C ethylbu~yl3tln~ oxide ls 31.06S~

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EXAMPLE 2 - Preparation of Tri(2,2-dimethylbutyl)tin Chloride A. Preparation of Methyl Tri(2,2-dimethylbutyl3tin To 12.2 g. (0.5 g~ atom) of magnesium chips heated to a temperature o~ 40C. under a nitrogen atmosphere was 11 added a 25 cc. portion of a solution containing 82.5 g.
(0.5 mole) of 1-bromo-2,2-dimethylbutane dissolved in 250 cc.
I of anhydrous tetrahydrofuran. The reaction was initiated ! using a few drops of ethylene d1bromide. The remaining port~on 1 of the 1-bromo-2,2-dimethylbutane solution was gradually ~i added during a period o~ one hour while the reaction mixture ! was heated to the boiling point. Heating was continued for an additional hour, during which time 6 cc. of a 3 normal li solutlon of methylmagnesium bromide in tetrahydrofuran was added to react with any impurities which could prevent or 15 '~ inhibit the formation of 2,2-dimethylbutyl magnesium bromide. 3 The reaction mixture was then allowed to cool to ambient temperature. A 250 cc. portion of this solut~on containing 0.18 mole of 2,2-dimethyIbutyl magnesium bromide was added dropwise to a stirred solution of methyltln trichloride ¦~ (14 g., 0. o6 mole) dissolved in 100 cc. of dry cyclohexane.
i The addition required O.b hour and was conducted under a nitrogen atmosphere. During the additlon the temperature o~
the reaction mixture was maintained below 40G. Following completion of the additlon the reaction mixture was heated ~ to the boiling point ~or one hour, then allowed to cool to ambient temperature To the resultant mixture was added a :~

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solukion containing lO0 cc. water and 25 g. citric acid. The organic phase of the resultant two phase liquid was separated and the water present therein removed using a portion of anhydrous magnesium sulfate, which was subsequently removed by filtration. The solvent was evaporated under reduced pressure to yield 43.4 g. of a liquid, crude methyl tri(2,2-dimethyl-butyl)tin. This liquid was distilled and the portion boiling from 87 to 92C. was collected. Analysis by vapor phase ¦! , I
" chromatography indicated that the product was 90% pure. The ~l product was found to contain 30.17% tin. The calculated value for methyl tri(2,2-dimethylbutyl)tin is 30.50%.

B. Cleavage of Methyl Tri(2,2-dimethylbutyl)tin to Tri(2~2-dimethylbutyl)tin Chloride I A 11.7 g.~ (0.03 mole) portion of the~methyl tri(2,2-, dimethylbutyl)tin prepared as described in part A of this ` example was dissolved in 50 cc. of dry pentane. To this solution was added a solution containing 7.8 g. (0.03 mole) of anhydrous stannic chloride and 50 cc. pentane. ~he , addition required 0.5 hour, following which the resultant 1 mixture was heated ko the boiling point for 0.5 hour and then allowed to cool to ambient temperature. A solution '~ ' .
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¦¦- obtained by combining 2 cc. of 12N aqueous hydrochloric acid and 100 cc. water was then added to the reaction mlxture wlth vlgorous stlrring both during the addition and for five ~ minutes thereafter. The organic layer of the resultant two- ¦
jl phase 1iquid was isolated and the water thereln removed using ,' a quantity of anhydrous magnesium sulfate. The solvent phase was then separated and concentrated under reduced pressure to yield 12.2 g. o~ a solid. Following one recrystallization ` from methanol, the produck weighed 8.6 g., was white in color and melted between 44 and 45C. Upon analysis khe compound was found to contain 28.66% tin. The calculated tin content ; for tri(2,2-dimethylbutyl)tin chloride is 28.98%.

! EXAMPLE 3 - Conversion of tri(2,2-diemethylbutyl)tin Chloride ~ to the Corresponding Hydroxide and Acetate I, Tri(2,2-dimethylbutyl)tin hydroxide was prepared !' :
by dlssolving 12.4 g. (0.03 mole) of the chloride, prepared as described in the preceding Example 2, in a mixture ; containing 25 cc. of methanol and 15 cc. of acetone. The resultant solution was added over a 15 minute period to a stirred solution containing 1.8 g. (0.045 mole) of sodium hydroxide, 520 cc. deionized water and 25 cc. methanol. The ~i, temperature of the reaction mixture was maintained below 25C. ¦
during the additlon of the chloride. Following completion of the addition the mixture was heated to the boiling point for I! 10 minutes using a water-cooled condenser. The solid product l~ was recovered from the reaction mixture by the addition of ~, 500 cc. deionized water and cooling to OoC. The product was then isolated, washed with water until the wash water was free ¦

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of detectable chloride, and then dried under reduced pressure.
¦ The weight of the final product was 11.0 g., equlvalent to a yield of 94%. The product was found to contain 31.16~ tin and ll no chlorlne. The calculated tin content for tri(2,2-dimethyl-~, butyl)tin hydroxide is 30.35%. Analysis by po~entiometrictitration indicated that the product was 97.9% pure. A 4.05 g.
(0.01 mole) portion of this material was converted to the ` corresponding acetate by dissolving it ln 100 cc. of dichloro- ¦
methane. To the resultant yellow solution was gradually added during a five minute period a solution containing o.66 g.
(0.011 mole) of glacial acetic acid and 50 cc. dichloromethane.
After stirring for ten minutes the solvent was evaporated ; under reduced pressure to yield 4.2 g. (98% yield) of a solid that was found to contain 27.25% tin. The calculated tin content ; of tri(2,2-dimethylbutyl)tin acetate is 27.40%.
' EXAMPLE 4 - Pesticidal Activity of Sterically Hindered Triorganotin Compounds Bis[tri(2-ethylbutyl)tin~ oxide and tri(2,2-di-` methylbutyl)tin chloride were evaluated to determine their efficacy as control agents for fungi and insects. The test procedures and results are summarized below.
Procedure 1 ¦ Bean plants infested with two-spotted spider mites , (Tetranychus bimaculatis) are sprayed to the saturation point i with an aqueous dispersion containing a specified concentrationl i, of the organotin compound in the form of a wettable powder consisting of equal parts by weight of organotin compound and a finely divided clay. The dispersions contained a small I~ amount of a nonionic surfactant. The percent mortalit~ is , observed three days after the plants are sprayed.

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Procedure 2 A bean plant is sprayed to the saturation point with an aqueous dlspersion containing a specified concentrationl, of the organotin compound. A number of cabbage loopers (Trichoplusia nl) are then placed on the leaves. The percent mortality is observed three days after the plants are sprayed.
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Procedure 3 This procedure is identical to Procedure 2 with the exception that the aqueous dispersion of the organotin compound is injected into the soil at the root zone in addi~ion to being sprayed onto the leaves of khe plant, and :
the mortality count is taken six days after the plant is sprayed.

Procedure 4 Grape plants are sprayed to the s~turation point with an aqueous dispersion containing the desired concentration of organotin compound, after which the plants are innoculated wlth grape downy mildew spores and placed in a 103% humldity environment for three days and in a greenhouse for an additional three days. Seven days after being sprayed, the plants are rated for control of the fungus. If no symptoms appear after seven days, the percent control is presumed to be 100%.
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1 Procedure 5 Tobacco plants are transplanted into soil infested with tobacco black shanlc (Phytophthora parasitica, var.
~ nicotiane). The soil is immediately drenched with an ! aqueous dispersion containing the desired concentration - of the organotin compound. The test is graded on the basis of transplant survival.

Procedure 6 j, i~ Adult German roaches are confined in cages and sprayed with an aqueous dispersion containing the desired concentration of orga~otin compound. A mortality count is taken three days after the insects are sprayed.

Procedure 7 ¦ Tender green bean plants with fu1ly expanded 15 ~ primary leaves were placed adjacent to plants infested with the powdery mildew fungus (ErsiPhe polygoni) 48 hours prior to the application of the organotin compound. The compound was applied by placing the plants on a revolving turntable I and spraying them with a formulation containing the 2 triorganotin compound. Once the spray had driedg the plants were placed in a greenhouse for between 7 and 10 days after which time the amount of mlldew on the primary leaves was i rated. Untreated plants served as controls.
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Efficacy of Bis[tri(2-ethylbutyl)tin] Oxide As A Pesticide ! j OrganismTest Concentration % Control li Procedure (parts per million) Spider Mite l 200 lO0 g7 ., .
Cabbage Looper 2 25 100 Tobacco Black Shank 5 .. 6.3 100 Powdery Mlldew 7 25 100 `I TABLE II
Efficacy of Tri(2,2-dimethylbutyl)tin Chloride , As A Pesticide OrganismTest Concentration ~ Control i Procedure (parts per million) Spider Mike 1 400 100 Cabbage Looper 3 400 100 -German Roach 6 400 Tabacco Black Shank 5 25 100 '.
Grape Downy Mildew 4 400 100 - Two compounds within the scope of this in~ention : were evaluated as miticides concurrently with two cbntrol ~ompounds3 tri(2~2-dimethylDut~l)tin chIoride and tric~rclo-; ~ hexyltin hydroxide, using test procedure l. The results of liS evaluatlon appear in the ~ollowing table.
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Compound (p.p.m.) % Mortality ITrl(2,2-dimethylbutyl)tin chloride (400) 100 " " " ( 25) 83 l " " " " (6.2) 40 1 Bis~tri(2-ethylbutyl)tin] oxide (400) 100 ( 25) 97 (6.2) 58 Controls Tri(3~3-dirnethylbutyl)tin chloride (400) 99 1~ Il " " ( 25) 0 Tricyclohexyltin hydroxide (400) 100 ii" " ( 25) 83 " ' " (6.2) 25 The compounds of this invent-lon effectively control mites at considerably lower use levels (6.2 parts per million) than prior art compounds such as tricyclohexyltin hydroxide.
This is economically advantageous, since less of the present compounds would be required to achieve a desired level of pest - control.
i None of khe plants tested using any of the foregoing test procedures were significantly damaged by the triorgânotin compound. By comparison, plants treated with the same amount ., , of linear triorganotin compounds, such as bis(tri-n-butyl)tin ; oxide have been killed or severely damaged. The present , triorganotin compounds are characterized by a low degree of phytotoxicity and a high level of efficacy as pesticides, particularly toward mitesO This desirable combination of properties is unusual for triorganotin compounds and is not 1~ characteristic of compounds containing linear alkyl or phenyl groups bonded to the tln atom. I

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Claims (16)

WHAT IS CLAIMED IS:

1. A novel triorganotin compound selected from the group consisting of and whereln R1 is methyl or ethyl, R2 is hydrogen, methyl or ethyl and n is 0, 1 or 2, with the proviso that each of the three hydrocarbon radicals bonded to the tin atom contains from 6 to 10 carbon atoms, X is selected from the group consisting of chlorine, bromine, fluorine, hydroxyl, nitrate, cyanate, thiocyanate, carbamate, thiocarbamate, , , , , , phenoxy, alkoxy (-OR4), dithiocarbamoyl , mercaptide (-SR3) and dialkyldithiophosphate wherein R3 represents alkyl containing from 1 to 12 carbon atoms or wherein Z is hydrogen, halogen, 1-3 carbon alkyl, 1-3 carbon alkoxy or nitro (-NO2), R4 is alkyl containing from 1 to 12 carbon atoms, Y is , wherein m is an integer from 2 to 10, inclusive, , oxygen, sulfur, sulfate, phosphate, or carbonate and a represents the valence of Y and is the integer 2 or 3.

2. A novel triorganotin compound according to Claim 1 wherein X is chlorine, bromine, fluorine or hydroxyl.

3. A novel triorganotin compound according to Claim 2 wherein X is chlorine or bromine.

4. A novel triorganotin compound according to Claim 1 wherein Y is oxygen.

5. A novel triorganotin compound according to Claim 1 wherein R1 and R2 are each methyl and n is 1.

6. A novel triorganotin compound according to Claim 1 wherein R1 is ethyl, R2 is hydrogen and n is 1.

17. In an improved method for protecting plants against infestations by fungi and insects by applying to said plants a fungicidally or insecticidally effective amount of a triorganotin compound, the improvement which resides in applying to said plants a triorganotin compound rep-represented by a formula selected from the group consisting of and wherein R1 is methyl or ethyl, R2 is hydrogen, methyl or ethyl and n is 0, 1 or 2, with the proviso that each of the three hydrocarbon radicals bonded to the tin atom contains from 6 to 10 carbon atoms, X is selected from the group consisting of chlorine, bromine, fluorine, hydroxyl, nitrate, cyanate, thiocyanate, carbamate, thiocarbamate, , , , , , phenoxy, alkoxy (-OR4), dithiocarbamoyl , mercaptide (-SR3) and dialkyldithiophosphate wherein R3 represents alkyl containing from 1 to 12 carbon atoms or wherein Z is hydrogen, halogen, 1-3 carbon alkyl, 1-3 carbon alkoxy or nitro (-NO2), R4 is alkyl containing from 1 to 12 carbon atoms, Y is , wherein m is an integer from 2 to 10, inclusive, , oxygen, sulfur, sulfate, phosphate, or carbonate and a represents the valence of Y and is the integer 2 or 3.

8. An improved method according to Claim 7 wherein X is halogen or hydroxyl.

9. An improved method according to Claim 8 wherein X is chlorine or bromine.

10. An improved method according to Claim 7 wherein Y is oxygen.

11. An improved method according to Claim 7 wherein R1 and R2 are each methyl and n is 1.

12. An improved method according to Claim 7 wherein R1 is ethyl, R2 is hydrogen and n is 1.

13. An improved method according to Claim 7 wherein said compound is dispersed in an inert carrier.

14. An improved method according to Claim 13 wherein said carrier is a liquld.

15. An improved method according to Claim 14 wherein said liquid is water.

16. An improved method according to Claim 7 wherein said insects are mites.