IL33922A - Rodenticide compositions containing silatrane compounds - Google Patents

Description

niauin Ο'^ΌΟΠ ,c'aen3a ' oi n'f sn Rodenticide conpositiouB coui^i i ^ si3.a rane compounds K ( )DP RODENTICIDE The present invention relates to biological toxicant compositions and to the use of certain silatrane compounds as biological toxicants and in particular as rodenticides .

Rodents such as mice, rats, rabbits, and squirrels are responsible for large financial losses every year. Rodents attack trees, nursery stock as well as various food plants.

It is an object of this invention to provide an improved method for killing rodents. An object of this invention is to provide an effective, fast-acting, single-dose poison for rats, mice, and other rodents.

Another object of this invention is to provide a primary poison exhibiting no secondary toxicity.

A further object of this invention is to provide a rodenticide leaving no persistent toxic residues.

A still further object of this invention is to provide a rodenticide which can be used to treat a variety of food formulations. The rodent problem has been recognized as serious for many years. Rats and mice, for example, are known to consume and spoil large amounts of grain and other foods, spread filth and diseases, kill chickens and the like. The United States Government estimates that the rodents annual board bill runs into hundreds of millions of dollars and that each rodent 33922/2 destroys many times what they eat. When one considers that this is only a small part of the overall rodent bill paid by the public along with the estimate that there are millions of rats and mice in the United States, the magnitude of the problem is readily apparent . It is clear, therefore, that any improvement in composition designed to eliminate rats or mice comes as a welcome contribution to the art. Also, in addition to causing injury, destruction or contamination of valuable property and goods, some species of rodents are the usual host of vectors of some human diseases such as bubonic plague, rickettsialpox and perhaps, mu rinetyphus .

This invention is a rodenticide comprising a carrier and an effective amount of an organic compoundt containing at least one silicon atom and at least one nitrogen atom.

This invention is a rodenticide comprising a carrier and an effective amount of a silatrane compound . of the formula: ' - . ■wherein R^, R2, and are hydrocarbyl radicals optionally substituted by one or more -inert substituents such as halogen, nitro, alkoxy or carboalkoxy radicals or hydrogen.

In this compound, Rx , Rz , R3, and R4 may be hydrocarbon radicals preferably selected from the group consisting of alkyl, alkenyl, cycloalkyl, aralkyl, aryl, alkaryl, including such radicals when inertly substituted. When Rx , R2 , R3, or R4_is alkyl, it may typically be straight chain alkyl or branched alkyl, including meLhyl, ethyl, n-propyl, iscpropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-amyl, neopentyl, isoamyl, n-hexyl, isohexyl, heptyls, octvls, decyls, dodecyls, tetradecyl, octadecyl, etc. Preferred alkyl includes lower alkyl, i.e. having less than about 8 carbon atoms, i.e. octyls and lower. When Rx , R2 , R3, or R4 is alkenyl, it may typically be vinyl, allyl, 1-propenyl, methallyl, buten-l-yl, buten-2-yl, buten-3-yl, penten-l-yl, hexenyl, heptenyl, octenyl, decenyl, dodecenyl, tetradecenyl, octadecenyl, etc. When Rx , R2 , R3, or R4 is cycloalkyl. it may typically be cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, etc. When Rx , R2 , R3, or R4 is aralkyl, it may typically be benzyl, β-phenylethyl, l/-phenylpropyl, β-phenylpropyl, etc. When » R2 » R3, or R4 is aryl, it may typically be phenyl, uaphthyl. etc. When Rx , R2 , R3 , or R4 is alkaryl, it may typically be tolyl, xylyl, p-ethylphenyl, p-nonylphenyl , etc. Ri . R2 , R3, or R4 may be inertly substituted, e.g. may bear ¾ non-reactive substituent such as alkyl, aryl, •cycloalkyl, aralkyl, alkaryl, alkenyl, ether, halogen, nitro, ester, etc. Typical substituted alkyls include 3-chloropropyl, 2-ethoxyethyl , carboethoxymethyl, etc.

Substituted alkenyls include U-chlorobutyl , i -phenylpropeny chloroallyl, etc. Substituted cycloalkyls include 4-methylcyclohexyl, «chlorocyclohexyl , etc. Inertly substituted aryl includes chlorophenyl, anisyl, biphenyl, etc. Inertly substituted aralkyl includes chlorobenzyl, p-phenylbenzyl , p-m&thylbenzyl , etc. Inertly substituted alkaryl includes 3-chloro-5-methylphenyl, 2, 6-di-t-butyl-4~chlorophenyl, etc.

Among the particularly preferred compounds of the formula: are those in which one of Rx , R2, 13, and R4 is phenyl.

Among the specific silatrane rodenticides effective in the practice of this invention are: -p-chlorophenyl silatrane, 5=phenyl silatrane, 5-p-chlorophenyl-3-methyl silatrane, 5-p-chlorophenyl-3, 7-dimethyl silatrane, 5-p-chlorophenyl-3, 7 , 10-trimethyl silatrane, 5-a-naphthoxy silatrane, 5-p-naphthoxy silatrane, 5-phenoxy silatrane, 5-benzyl silatrane, and phenylethyl silatrane .

Another aspect of thi invention is a rodenticidal water bait comprising an aqueou solution containing a compound of the formula: R2 wherein Rj. , R2 , R3, and R4 are Jty4j¾>c-ajibms-,- defined as above The rodenticides of this invention are single-dose, quick-acting toxicants affecting the central nervous system. Therefore, they are not subject to resistance build-up» The rodenticides of this invention exhibit little or no dermal or eye toxicity, leave non-toxic residues after the expiration or seven days, and no secondary poisoning since detoxification occurs in the primary animal. Another feature of this invention is that a broad spectrum of rodents are susceptible to the lethal effects of the rodenticides of this invention.

The dermal toxicity of 5-p-chlorophenyl silatrane is very low, the dermal L, being > 2500 mgm/kg. 50 This invention provides a composition of improved palatibility, preferability, and acceptibil ity to the rodent and thus, enhances the desire of the rodent to consume the bait. Consequ ntly, the intake of rodenticides by rats or mice is increased and a relatively faster and effective kill is obtained,, The active components of this invention, unlike most toxic, fast-acting rodenticides which cause the immediate death of the rodents do not cause bait shyness. Bait shyness is the aversion to bait exhibited by rodents after witnessing the death of the few rodents which initially tested the baits.

The rodenticide bait of the composition of the present invention can be any of the commonly employed solid food baits or water baits which have been provided with effective concentrations of the rodenticide. The foods most extensively employed in the solid food type bait are grains. The grain can be any whole grain such as corn, wheat, rye, rice, barley, malt, oat, groats, peanut hearts, or the like, singly or in admixture, fragments of these grains, or pellets made by any means from these grains.

The carrier of the silatrane rodenticides of this invention may also be particles of inorganic or mineral materials such as a sand. Solid carrier agents are preferably not hygroscopic, but materials which would render the composition permanently dry and free-flowing. Suitable solid carriers include clays, such as the bentonites and attapulgites ; other minerals in natural state such as talc, diatomaceous earth, chalk, kaolin, volcanic ash, salt, and sulfur; powdered cork, powdered wood, etc.

Other baits include: ground beef, canned dog food, dried dog food, canned fish, cat food, cake, doughnuts, bread crumbs, and peanut butter.

Admixture of the poison can be by any method familiar to those skilled-in-the-art including coating, impregnating, spraying or similar treatment of the solid food bait with the poison. Water baits are normally water containing the water soluble rodenticides of this invention dissolved therein.

The amount of poison generally provided for the bait varies depending upon the particular bait employed whether it is a food or water type and the degree of toxicity of the rodenticide of this invention toward human and domestic animals. Ordinarily, the amount of rodenticide will fall into the range of about 0.005%^ to 10% by weight.

Additives may be used with the rodenticides of this invention and with the bait to improve the palatibility and acceptance of the rodenticide and thereby, insure a lethal intake of the poison by the rodents. The rodenticide composition of the present invention has a special advantage in regard to the destruction of mice. Mice often present a special problem, since unlike rats, they prefer to chew or pick at their food with very small intake at one time. Mice are nibblers, feeding anywhere from 18 to 25 times in 24 hours and will not ordinarily consume a lethal amount of a rodenticide unless it is of a particular puissant type. The rodenticides of this invention fall within the particularly lethal type.

One particular advantage of the rodenticides of this invention is their partial solubility in' water.

Most prior art rodenticides are insoluble in water and accordingly, must be presented in the form of dry baits prepared by mixing the rodenticide with a rodent food or foods. In locations where natural and luatiufa fcureu food stuffs are available to rodents, for example, in barns, grain elevators, food processing plants, and the like, the rodents will invariably acpept the natural or manufactured food stuffs in preference to the poison dry bait no matter how attractively the latter is prepared and presented. In such an environment, the probability of a rodent gestating a poison dry bait is no greater than and is considerably less than the ratio of said bait to the other food available to the rodent. However, rodents do require water especially when feeding and it is much easier to eliminate the rodent's available water supply as in barns, grain elevators, food processing plants, and the like, than it is to render unavailable supplies of natural or manufactured foods in such structures.

Water baits, along with compositions used to prepare water baits, for example, which are relatively stable in this respect differ from finished food baits which are* subject to the inherent defects of packaged foods, e.g. staling, rancidity, moulding, insect infestation, etc. All of which can make the bait unpalatable to the rodent. Water baits are particularly desirable to control rodent population in and around grain storage elevators, mills, grain and other food processing establishments where grain and other food saturation exists and where sources; of water are not readily available to the rodent.

When presented in this manner, the rodent will ingest such water baits during feeding. Also, the rodenticidal water baits are much more effective than dry baits, due probably to more rapid absorption of the rodenticide in solution. The silatrane rodenticides of this invention are partially soluble in water and accordingly, it is possible to prepare rodenticidal water baits containing these compounds.

Water bait may be made using distilled water. Rain water, deionized water, zenolite softened water (but not alum softened water) are stable but waters of these types possess a foreign taste as far as rodents are concerned. ■ Accordingly, such water baits are less acceptable than baits made with water with which the rodents are familiar. Also, obviously, waters of these types are not necessarily conveniently available. It is a feature of this invention that water hardness or quality is not detrimental to the effectiveness of the rodenticide of this invention. The stable rodenticidal water can be prepared by incorporating an appropriate quantity of the silatrane, e.g. 0.01-0.02 ounces of rodenticide per gallon of water mixed thoroughly. A sugar additive of the present water bait may be provided in amounts sufficient to increase the palatibility and acceptability of said water bait. The amount may be up to 20% of the total weight of the composition. The amount may vary from 0.1% to 20% by weight. Sugar additives may be incorporated into the composition by any convenient manner, as for instance by the simple mixing of the rodenticide in water and dissolution of sugar in the composition. Incorporation of the sugar can be conducted prior to the inclusion of the silatrane rodent poison in the bait, after the preparation of the rodenticide bait, or the rodenticide and sugar can be added together..

The, rodenticide of this invention may be tableted for marketing, each packet, or tablet, containing a sufficient material to produce the improved rodenticide of this invention when dissolved in a convenient volume, say 1 quart of water. A more generally acceptable procedure involves the preparation of a liquid concentrate of definite volume which is added to a definite volume of water to produce the novel rodenticidal water bait of this invention. 1.012 ounces of the rodenticide of this invention will make one gallon of poison water bait.

The addition of sugars to the water bait rodenticide composition is preferred but materials such as glycerine, sorbitol, mannitol, saccharine, and a sweetening agent known as Sucaryl may be added in small amounts if desired. Salt (NaCl) up to about 0.055% may also be added to the rodenticide compositions or bait solutions. Suitable dyes may be added to color the water of the final bait or the rodenticide composition.

For example, dye may be incorporated in the composition of the present invention by addition to the silatrane solution before application into the carrier or by addition into the carrier prior to the application of the silatrane solution. When a dye is used it should be substantially odorless and tasteless and stable at the pH ranges of the solutions in which it is used.

The rodenticide compositions of the present invention require the services of professionally licensed exterminators. The silatrane compound of this invention, unlike certain poisons such as the phosphorus compound, do not produce repellent breakdown products. The activity of the silatrane rodenticides is sufficiently rapid that the rodents which have ingested said rodenticide do not have a chance to warn the rodent colony of impending danger.

While this invention is described exclusively in connection with the destruction of rodents, the invention is not limited thereto. Rats are the most difficult rodent to destroy and, accordingly, were chosen to illustrate the effectiveness of the water baits and solid baits of this invention. However, such rodenticidal compositions are highly effective against rodents in general such as mice, squirrels, rabbits, prairie dogs, beaver, and the like. i t The desired amount of reactants is placed in a suitable reaction vessel where the reactants are thoroughly admixed and heated to reflux. Reflux is continued until a predetermined amou t of morioh drie alcohol, one of the products of the reaction, is removed.

The nitrogen coordinated silicon compound will be a crystalline solid or liquid depending up6n the reactants employed. 'The crystalline solid compound may be purified by recrystallization from the solvent or by other conventional means if desired.

When the reactants are reacted on a one to one molar basis, it may be desirable to employ an admixture with the reactants at least 5% by weight of an inert solvent that will form an azeotrope, 5-p-chlorophenyl silatrane , 6 , ll-trioxa-l-aza-5-p-chlorophenylsila-tricyclo [3,3,3,0 undecane) is effected by the reaction p-chlorophenyl triethoxy silane with triethanol-amine.

The preparation of p-chlorophenyl triethoxy silane is effected by the reaction of p-chlorophenyl magnesium chloride with tetraethoxy silane. p-chlorophenyl magnesium chloride is synthesized from dichlorobenzene and magnesium using tetrahydr.ofurari as the solvent by the normal Grignard techniques. Ethylene dibromide is used as the initiator. The Grignard reagent thus formed is then added to a solution of tetraethoxy silane in toluene. Reverse addition and an excess of tetraethoxy silane is used to minimize the formation of higher arylated products. The magnesium chloroethpxide by-product is filtered and washed thoroughly with solvent and the organic phase is then distilled. After removal and recovery of the solvents, the p-chlorophenyl triethoxy silane must be distilled to separate it from higher boiling alkylated products. p-chlorophenyl triethoxy silane is then reacted with triethanol amine using xylene as the solvent and the reaction mixture heated to reflux using a fractionating column. The theoretical amount of by-product, ethanol, is collected first and then about three fourths of xylene is distilled off. On cooling 5-p-chlorophenyl silatrane · was crystallized. It can be purified by recrystallization from ethanol.

The recrystallized product 5-p-chl.orophenyl silatrane is a white crystalline solid exhibiting, a melting point, of 233°C to 235°C. This compound is a strong nitrogen silicon coordinate bond. The product is solubl in most organic solvents such as benzene, chloroform, ethanol, tetrahydrofuran , and acetone. It can be recrystallized from' benzene, toluene, or ethanol. It is odorless and nonflammable. The product is almost indefinitely stable when stored at room temperature.

The foregoing synthesis of 5-p-chlorophenyl silatrane may be represented by the following equations: CI The following examples will serve to illustrate the present invention: EXAMPLE 1 A dry control bait composition was prepared containing the following components: TABLE I Percentage Component (by weight) Corn oil 5% Sugar 5% Rolled oats 90% A toxic bait identical with the foregoing except that it contained 0.25% 5-p-chlorophenyl silatrane , ll-trioxa-l-aza-5-sila-5-p-chlorophenyltricyclo [3,3,3,0 1'3] undecane) was prepared. Acceptance tests were performed with white laboratory rats on a free choice basis under identical conditions. The animals fasted overnight before being tested. In such free-choice conditions, the rats ate more of the lethal bait than the control bait. The following tables set forth the results of the bait acceptance.

TABLE II BAIT ACCEPTANCE TEST Animals fasted overnight before test Active Ing, Animal Amt. Bait Fed Amt. Eaten Ov Cone, in Weight gram gram Toxic Bait Toxic Control Toxic Co 2.5 mg/gm 0.206 10 10 1.5 2.5 mg/gm 0.168 10 10 1.0 2.5 mg/gm 0.178 10 10 2.0 2.5 mg/gm 0.150 10 10 1.0 1 2.5 mg/gm 0.192 10 10 1.0 TABLE III BAIT ACCEPTANCE TEST Animals fasted four hours before test Active Ing. A imal Amt. Bait Fed Amt. Eaten Over Cone . in Weight gram gram Toxic Bait kg Toxic Control Toxic Cont 2.5 mg/gm 0.189 10 10 2.75 1.5 2.5 mg/gm 0.183 10 10 3.50 1.2 2.5 mg/gm 0.206 10 10 3.25 1.0 2.5 mg/gm 0.156 10 10 2.25 1.5 2.5 mg/gm 0.177 10 10 2.75 0.0 2.5 mg/gm 0.202 10 10 1.00 1.7 2.5 mg/gm 0.191 10 10 0.75 7.0 2.5 mg/gm 0.167 10 10 1.25 0.7 2.5 mg/gm 0.178 10 10 2.0 1.7 EXAMPLE 2 A high protein bait composition was prepared by mixing the following components: TABLE IV Composition (by weight) . f ~ __ White corn meal 65 parts Fish meal 20 parts Hog Protein Supplement -"- 5 parts Fish Blocks- 5 parts Corn oil 5 parts -p-chlorophenyl silatrane .25 - .75 #The Hog Protein Supplement upon analysis contained: Protein analysis 36% Crude fat 2% Crude f ber Calcium (max.) 5.5% mi . 4.5% Phosphorus (min 2.5% Iodine (min.) ■ 0.0015% Salt (NaCl) (max 2.0%' The Hog Protein Supplement contained: soybean, meat and bone meal, dehydrated alfalfa meal, cottonseed meal, dried corn fermentation solubles, corn distillers dried solubles, fish meal, 'irradiated dried yeast (Vit.D-2), Vitamin A Palmitate, Vitamin B-12 supplement, riboflavin, calcium pantathenate, niacin, choline chloride, defluorinated rock phosphate - 6%, and salt - 2.0%. ; # Fish Block is comprised, substantially, of cottonseed meal, soybean meal, fish meal, meat and bone meal, hydrolyzed poultry feathers, dehydrated alfalfa meal, grain sorghum flour, rice bran, wheat shorts, dried whey, corn distillers dried grain solubles, dried molasses, cane molasses, iron oxide, salt, calcium carbonate, dicalcium phosphate, manganous oxide, ferrous carbonate, copper oxide, cobalt carbonate, calcium iodine, choline chloride, d-pantothenic acid, riboflavin supplement, niacin, menadione sodium bisulfi complex (source of Vitamin K, activity), Vitamin E supplement, Vitamin A Palmitate (stability improved), Vitamin B-12 supplement, D-Activated animal sterol The foregoing components were mixed thoroughlv with 0.5%, by weight, of 5-p-chlorophenyl silatrane.

Paper rolls containing the rodenticidal bait were placed at sixteen sites at the Louisiana State Penitentiary for Women, Iberville Parish, St. Gabriel, Louisiana. The test area at the State Penitentiary for Women encompassed the housing for prisoners, nearby grain mill, and a large building used to store corn.

The rodenticide was placed in several locations in each of the buildings.

Rats consumed quantities of the rodenticidal bait and died within thirty minutes of the placement of the rodenticidal bait. Within two days a total of sixteen rats had been killed by ingestion of the rodenticidal bait.

EXAMPLE 3 A high protein bait composition was prepa of the following: TABLE V Component Composition (by weight) White corn meal 65 parts Fish meal 20 parts Hog Protein Supplement 5 parts Fish Block 5 parts Corn oil . 5 parts The foregoing composition was prepared by mixing the dry components thoroughly and then adding corn oil.

To separate quantities of the foregoing bait composition were added 0.25% 5-p-chlorophenyl silatrane, 0.5% -p-chlorophenyl silatrane, and 0.75% 5-p-chlorophenyl 3, 7 , 10-trimethyl silatrane.

Samples of the foregoing rodenticidal compositions were placed at randomly selected places in the general vicinity ofj the Plaquemine Dump, Iberville Parish, Plaquemine, Louisiana. Four rats were observed to have been killed at the end of twenty-four hours .

EXAMPLE A water bait rodenticidal composition was prepared of the following: TABLE VI Compo nt Percentage (by weight) Water 79.799 % Sugar 20.0 % Tween 80 .001 % -p-chlorophenyl silatrane (4,6, ll-trioxa-l-aza-5-sila-5-p-chlorophenyltricyclo [3,3,3,0 i undecane) 0.01% Cups containing the foregoing water bait rodent cide were randomly placed in the Plaquemine, Louisiana City Dump, 1 Iberville Parish. The samples of bait were monitored for seventeen hours. Six rats were * observed drinking the water bait rodenticides. The six rats died and their bodies were recovered The baits, thereafter, were immediately removed and destroyed.

EXAMPLE 5 The lack of secondary poisoning by the rodenticide of this invention was established by giving mice massive oral doses (8.125 mg) of 5~p~chlorophenyl silatrane (4,6, ll-trioxa-l-aza-5~sila~5~p~chlorophenyltricyclo . [3,3,3,0 l'5] undecane) whereupon the mice died. Immediatel thereafter, the dead mice were offered to white laboratory rats (average wt„ of 300 grams). No toxic symptoms were observed in the white laboratory rats during the 48 hours following thereafter.

EXAMPLE 6 < The oral toxicity (the minimum lethal dose which is fatal to 50% of the test animals) of three silatranes was determined by placing the compounds by stomach tube into the test animals (white rats). The results are set forth in Table VII.

TABLE VII Oral toxicity of silatranes (white rats).

L mgAg Silatrane D -50 -phenyl silatrane 0.4 ~p~phenethyl silatrane 5-10 -p-chlorophenyl silatrane 5-10 EXAMPLE 7 A dry rodenticidal bait composition was prepared from the following components: TABLE VIII Component Percentage (by weight) Corn oil Rolled oats 44.85% Corn meal 44.90% Sugar 5.0% -p-chlorophenyl silatrane (4,6, ll-trioxa.-l-aza~5~sila-5-p~chlorophenyltricyclo [3,3,3,0 undecane) 0.25% A control ba'it identical with the foregoing except that it contained no rodenticide was prepared.

Weighed portions of the toxic, rodenticidal bait composition were introduced into a cage containing three preweighed white, male laboratory mice exhibiting weights in the range of twenty-two to twenty-three grams. Weighed amounts of the control bait containing no 5-p-chlorophenyl silatrane were introduced into a separate cage containing three additional white laboratory mice. The mice contacted the rodenticidal bait within 7 minutes after the bait was made accessible to them. Two mice died 4 minutes after initial contact with the rodenticidal bait. The surviving mouse that ingested the rodenticide suffered muscle spasms and convulsions.

Mice in the cage containing the control bait which contained no rodenticide contacted the control bait within 5 minutes. None of the animals ingesting the control sample exhibited deleterious effects.

EXAMPLE 8 The minimum lethal concentrat on of 5-p-chloro-phenyl silatrane was ascertained by compounding baits containing 5% corn oil, 45% rolled oats, 45% corn meal, and varying quantities of 5-p-chlorophenyl silatrane.

The amounts of rodenticide in the several samples were 0.5%, 0.25%, 0.125%, 0.0625%, and 0.03125% 5-p-chlorophenyl silatrane. Samples of one of the different concentrations of rodenticide were placed in one of several cages containing preweighed mice which had fasted for twenty-four hours.

It was determined that the critical concentration of -p-chioropheuyl silatrane was 0.125% when incorporated into a grain bait. The ready acceptability of the rodenticide was illustrated by the fact that the time for mice to contact the. rodenticidal baits and baits containing no rodenticide was substantially the same.

EXAMPLE 9 The concentration of various rodenticides of this invention and the quantity needed to kill 50% of rats tested were determined in tests similar to those set forth in Example 8. The results are set forth below in Table IX.

TABLE IX -phe.nyl silatrane 3-5 5.0% Poor -p-chlorophenyl~3, 7-dimethyl silatrane 42 2.5% Poor -p-chlorophenyl-3, 7 , 10-trimethyl silatrane 301 2.5% Good -a-naphthoxy silatrane 100 5% Good -p-naphthoxy silatrane 100-200 5% Good -benzyl silatrane 66 1% Good EXAMPLE 10 A water-based rodenticide was prepared bv dissolvin a concentrate of 5% 5-p-chlorophenyl silatrane in a sugar base in water to obtain a solution of 100 parts per million of 5-p-chlorophenyl silatrane in water. The rodenticidal solution was offered to three white mice exhibiting weights of twenty to twenty-four grams as their drinking water.

The three, mice died after drinking the water bait rodenticide EXAMPLE 11 To obtain a more complete spectrum of the toxicity hazards of silatrane compounds, dermal toxicity studies were conducted. The procedure consisted of shaving the trunks of rabbits, New Zealand White Strain weight 2-3 kgs, and abraiding epidermally the exposed area with a hypodermic needle without drawing blood. The test compounds were - 2k - applied to approximately 10% of the exposed area and the trunk was then wrapped with polyethylene sheeting and taped at both ends. Various dosage levels were tested.

The results of this study appear in Table X.

TABLE X Compound Dermal Toxicity Phenyl silatrane > LD50 500 mg/kg β-phenylethyl silatrane > LD30 300 mg/kg -p~chlorophenyl' silatrane > LD50 2500 mg/kg 3,5~dichlorophenyl silatrane > LD30 300 mg/kg EXAMPLE 12 To illustrate the absence of secondary poisoning in. the practice of this invention, 5-p-chlorophenyl silatrane was administered to laboratory mice thereby killin them; these dead mice, in turn, were used as a controlled bait to determine their toxic effects. The length of time expiring between the death of each mouse and the ingestion of said mouse by a rat was between five and ten minutes, the rats having fasted overnight. The results presented in Table XI below show that no secondary poisoning results from the. use of the rodenticides of this invention.

TABLE XI CONSUMPTION OF POISONED MICE BY WHITE LABORATORY ' RATS Active. Active Wt. of Wt. of Amt. of each ingredient ingredient each each mouse consumed consumed by consumed by mouse rat by the rat each mouse each rat grams grams H£ g mg Wt/rag mg/k 18.2 291.0 18.2 100.0 8.125 8.125 27.9 I A 302.0 13.1 53.7 8.125 4.360 I A 20A 291.0 15.0 73.5 8.1.25 5.970 20.5 22.9 311.0 22.9 100.0 0 0 0 EXAMPLE 13 A rodenticide bait composition was prepared of the following: i TABLE XII Compo ent Percentage (by weight) Sugar 5.0% Corn oil 5.0% Rolled oats 3.75% Corn meal 43.75% -p-chlorophenyl 3,7,10-trimethyl silatrane 2.5% Three white male mice were weighed and, fasted for twenty=four hours whereupon the foregoing rodenticidal bait was made accessible to the three mice. The mice contacted the bait within two minutes and died at least 74 hours but less than 114 hours later. The delayed toxicity exhibited by this particular rodenticide permits the application of an antidote in the case of accidental ingestion.

While this invention has been described with specific details and specific examples, these are illustrative only and are not to be considered limitations of this invention except as these may be incorporated in the appended claims. 33922/2

Claims (1)

1. CLAIMS A composition comprising a carrier and as an a ctive component an effective amount of a compound of the wherein and are hydroearbyl radicals optionally substituted by one or more inert euch as or or composition Claim 1 wherein said rodenticide bait is a solid food She composition of Claim 1 wherei said bait is a water composition of Claim 1 wherein is composition of Claim 1 wherein said compound is composition of Claim 1 wherein said compound is A bait composition comprising water and a predetermined lethal a compound of the formula Ion Claim 29 water bait composition of Claim 7 wherein said compound is J water bait composition Claim 7 wherein said compound is A rodenticidal concentrate comprising sugar and as an essential component a toxic of a compound of the formula A method for killing rodents comprises applying to rodents an effective amount of a compound of 1 in Claim e method of Claim 11 wherein said compound applied method o Claim 11 wherein said compound is The method of Claim 11 wherein said compound is trimethyl insufficientOCRQuality