Halobenzoylpropionic acid esters as insect repellants

Abstract

NEW AND VALUABLE HALOBENZOYLPROPIONIC ACID ESTERS WHICH HAVE A STRONG REPELLENT ACTION ON INSECTS, AND A PROCESS FOR REPELLING INSECTS WITH THESE ACTIVE INGREDIENTS.

Claims

United States Patent Office 3,702,892 Patented Nov. 14, 1972 3 702 8 92 HALoBENzoYLrRdPrdMc ACID ESTERS AS INSECT REPELLANTS Gerhard Bachmann and Heinrich Adolphi, Ludwigshafen, The halobenzoylpropionic acid esters may be prepared by reacting the halobenzoylpropi-onic acids, obtained by reaction of halobenzenes with succinic anhydride, with the appropriate alcohols in the presence of a mineral acid. Germany, assignors to Badische Anilin- & Soda-Fabrik Example illustrating the preparation of the Aktiengesellscha ft, Ludwigshafen (Rhine), Germany active ingredients gg ggg ffis gg gggz bgg 'g gfhg gfg 25 0 parts (by weight) of bromobenzene, 30 parts of P 19 23 916.3 succmic anhydride and 90 parts of anhydrous aluminum I t, 01 9 24 10 chloride are stirred for 2 hours on a boiling water bath. US. Cl. 424-308 5 Claims After cooling, first 150 parts of water and then 50 parts of concentrated hydrochloric acid are dripped into the mixture. The excess bromobenzene is distilled 011 with ABSTRACT OF THE DISCLOSURE steam. The oily residue, which solidifies upon cooling, is New and valuable halobenzoylpropionic acid esters separated, dissolved in sodium carbonate solution, filtered which have a strong repellent action on insects, and a Precipitated g n by acidifying with hydrochloric process for repelling insects with these active ingredients. gi gi sgg ggg z ggg gg r g g i g g s a 5% 140 to 143 C. is obtained. The invention relates to new and valuable halobenzoylp-Bromobenzoylpropionic acid ethyl ester :31'5313101'1321 acid esters agd agents for repelling insects con- 200 parts of p bromobenzoylpmpionic acid and 2400 ammg ese compoun s. In to the of assassinate;sass? assis s; some insects ymeanso insectici esw ic t einsects or impair their vital power, the repelling of insects within- $3233} zz g ffii g g g g gga g f g 1S a t sefctguges 18 of g fii i f l Is obj? neutral and dried 213 parts of p-b romo lsenz zy l pfop r ii c 0 ese compoun s, w 1c ave no one action on mo o sects, to prevent the insect pests from settling on a surface gg g i g ester havmg a melting pomt of 56 to 57 ggf i these agents the skm of humans or The following halobenzoylpropionic acid esters are It is known to use dimethyl phthalate and m-toluic acidhsted by way of examp 1e: N,N-diethylamide as insectifuges; however, their action is not Sat sfacto y Hal- C 0-CH:CH:COOR A 1:! mriiienmo. p ii ri i d. B1. 91 4a 96 57 90 as 85 145 o./0 15 mm it as: sta -oH,-oH,-ci.- so ""as s a 85 58 11-0411: 84 5O We have now found that halobenzoylpropionic acid esters having the formula XQ-ow-cm-om-oo-on where X denotes a halogen radical (chlorine, iodine, preferably bromine) and R denotes an aliphatic hydrocarbon radical having 1 to 10 carbon atoms (methyl, ethyl, npropyl, isopropyl, n-butyl, isobutyl, n-pentyl, isopentyl, nhexyl, 2-ethylhexyl, nonyl, and decyl), which may be substituted by halogen (chlorine, bromine, iodine), hydroxyl or alkoxyl (methoxyl, ethoxyl), are eminently suitable as insectifuges. Some examples of substituted aliphatic hydrocarbon radicals are Z-methoxyethyl, Z-ethoxyethyl, 2- butoxyethyl and 2-chloroethyl. It is preferred to use the p-bromobenzoylpropionic acid esters. The active ingredients may be applied in such a way that the objects to be protected against insect attack, e.gi inanimate objects such as wood, leather and paper, or living creatures such as humans and animals (pets, ungulata), are treated especially on the surface (skin) with the active ingredients. The agents according to the invention may be used as solutions, emulsions, suspensions or dusts. The form of application depends entirely on the purpose for which the agents are being used; in any case it should ensure a fine distribution of the active ingredient. For the preparation of solutions to be sprayed direct, hydrocarbons having boiling point higher than C., e.g. tetrahydronaphthalene or alkylated naphthalenes, or organic liquids having boiling points higher than 150 C. and having one or more than one functional group, e.g. the keto group, the ether group, the ester group or the amide group, this group or these groups being attached as substituent(s) to a hydrocarbon chain or being a component of a heterocyclic ring, may be used as spray liquids. Aqueous formulations may be prepared from emulsion concentrates, pastes or wettable powders by adding water. To prepare emulsions the ingredients as such or dissolved in a solvent may be homogenized in water or organic solvents by means of wetting or dispersing agents, e.g. polyethylene oxide adducts. Concentrates which are suitable for dilution with water may be prepared from active ingredient, emulsifying or dispersing agent and possibly solvent. Dusts may be prepared by mixing or grinding the active ingredients with a solid carrier, e.g. kieselguhr, talc, clay or fertilizers. The following experiments demonstrate the use of the agents according to the invention. EXAMPLE 1 Action on Aedes aegypti (gnat): The apparatus for the experiment consists of two boxes each 50 cm. long which are separated from each other by a 2.5 mm. mesh gauge screen. The screen is impregnated with a 0.1% (by weight) acetonic solution of the active ingredients. After the solvent has evaporated, 300 gnats are introduced into one of the boxes. At varying intervals in time, counts are made as to (a) how many gnats have settled on the screen, and (b) how many gnats have crossed through the treated screen into the empty box. Result (a) Number 01 gnats on the screen Time 80 mins. 150 mins. 4% hrs. 6 hrs. Active ingredient No. 2 0 1 4 Dimethyl phthalate 16 38 40 38 Control (untreated) 70 60 G0 45 Result (b) Number of gnats in the second box Time 10 mins. 30 mins. 1 hr. 2 hrs. 6 hrs. Active ingredient No. 2 1 1 3 5 30 Dimethyl phthalate 8 15 25 60 110 m-Tolulc acid-N,N- diethylarnide 10 7 12 30 Control (untreated) 50 90 115 140 210 These results show that active ingredient No. 2 is far superior to the known active ingredients employed for comparison purposes. EXAMPLE 2 In feeding tests with houseflies (Musca domestica), an addition of 0.25% (by weight) of active ingredients Nos. 1, 2, 4 and 7 to lactose tablets prevents hungry houseflies from feeding on the tablets. EXAMPLE 3 60 parts by weight of compound 1 is mixed with 40 parts by weight of N-methyl-a-pyrrolidone. A mixture is obtained which is suitable for application in the form of very fine drops. EXAMPLE 4 20 parts by weight of compound 2 is dissolved in a mixture consisting of 80 parts by weight of xylene, 10 parts by weight of the adduct of 8 to 10 moles of ethylene oxide to 1 mole of oleic acid-N-monoethanolamide, 5 parts by weight of the calcium salt of dodecylbenzenesulfonic acid, and 5 parts by weight of the adduct of 40 moles of ethylene oxide to 1 mole of castor oil. By pouring the solution into 100,000 parts by weight of water and uniformly distributing it therein, an aqueous dispersion is obtained containing 0.02% by weight of the active ingredient. EXAMPLE 5 20 parts by Weight of compound 3 is dissolved in a mixture consisting of 40 parts by weight of cyclohexanone, 30 parts by Weight of isobutanol, 20 parts by weight of the adduct of 7 moles of ethylene oxide to 1 mole of isooctylphenol, and 10 parts by weight of the adduct of 40 moles of ethylene oxide to 1 mole of castor oil. By pouring the solution into 100,000 parts by weight of Water and uniformly distributing it therein, an aqueous dispersion is obtained containing 0.02% by weight of the active ingredient. EXAMPLE 6 20 parts by weight of compound 4 is dissolved in a mixture consisting of 25 parts by weight of cyclohexanol, 65 parts by weight of a mineral oil fraction having a boiling point between 210 and 280 C., and 10 parts by weight of the adduct of 40 moles of ethylene oxide to 1 mole of castor oil. By pouring the solution into 100,000 parts by weight of water and uniformly distributing it therein, an aqueous dispersion is obtained containing 0.02% by weight of the active ingredient. EXAMPLE 7 20 parts by weight of compound 5 is well mixed with 3 parts by weight of the sodium salt of diisobutylnaphthalene-a-sulfonic acid, 17 parts by weight of the sodium salt of a lignin-sulfonic acid obtained from a sulfite waste liquor, and 60 parts by weight of powdered silica gel, and triturated in a hammer mill. By uniformly distributing the mixture in 20,000 parts by weight of water, a spray liquid is obtained containing 0.1% by Weight of the active ingredient. EXAMPLE 8 3 parts by weight of compound 6 is intimately mixed with 97 parts by weight of particulate kaolin. A dust is obtained containing 3% by weight of the active ingredient. EXAMPLE 9 30 parts by weight of compound 2 is intimately mixed with a mixture consisting of 92 parts by weight of powdered silica gel and 8 parts by weight of paraffin oil which has been sprayed onto the surface of this silica gel. A formulation of the active ingredient is obtained having good adherence. We claim: 1. A process for repelling insects which comprises applying to the skin of humans or animals exposed to settling by insects thereon an insect-repellant amount of a halobenzoylpropionic acid ester having the formula Q4: o-cm-cm-c o-on References Cited Chemical Abstracts, 1961, vol. 55, p. 1521e. ALBERT T. MEYERS, Primary Examiner V. D. TURNER, Assistant Examiner U.S. Cl. X.R. 424-Dig. l0

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