Insect repellent compounds

Abstract

Dihydronepetalactone, a minor natural constituent of the essential oil of catmints (Nepeta spp.) such as Nepeta cataria , has been identified as an effective insect repellent compound. Synthesis of dihydronepetalactone may be achieved by hydrogenation of nepetalactone, the major constituent of catmint essential oils. This compound, which also has fragrance properties, may be used commercially for its insect repellent properties.

What is claimed is:  
     
         1 . An insect repellent composition comprising a dihydronepetalactone, or a mixture of dihydronepetalactone stereoisomers, represented by the general formula:  
       
         
           
           
               
               
           
         
       
     
     
         2 . The composition of  claim 1  wherein the dihydronepetalactone stereoisomers are (9S)-dihydronepetalactone stereoisomers derived from (7S)-nepetalactones.  
     
     
         3 . The composition of  claim 1  which comprises 1S,9S,5R,6R-5,9-dimethyl-3-oxabicyclo[4.3.0]nonan-2-one.  
     
     
         4 . The composition of  claim 1  which comprises dihydronepetalactone in an amount of at least about 0.001% by weight of the total weight of the composition.  
     
     
         5 . The composition of  claim 1  which comprises dihydronepetalactone in an amount of from about 0.001% to about 80% by weight of the total weight of the composition.  
     
     
         6 . The composition of  claim 1  which comprises dihydronepetalactone in an amount of from about 0.01% to about 50% by weight of the total weight of the composition.  
     
     
         7 . The composition of  claim 1  which comprises one or more of the members of the group consisting of an adjuvant, a carrier and an insect repellent compound that is not a dihydronepetalactone.  
     
     
         8 . The composition of  claim 7 , wherein the adjuvant is selected from the group consisting of thickeners, buffering agents, chelating agents, preservatives, fragrances, antioxidants, gelling agents, stabilizers, surfactants, emolients, coloring agents, aloe vera, waxes, and therapeutically or cosmetically active ingredients.  
     
     
         9 . The composition of  claim 7 , wherein the carrier is selected from the group consisting of silicone, petrolatum, lanolin, liquid hydrocarbons, agricultural spray oils, paraffin oil, tall oils, liquid terpene hydrocarbons and terpene alcohols, aliphatic and aromatic alcohols, esters, aldehydes, ketones, mineral oil, higher alcohols, finely divided organic and inorganic solid materials.  
     
     
         10 . The composition of  claim 7 , wherein the carrier comprises an aerosol composition adapted to disperse the dihydronepetalactone into the atmosphere by means of a compressed gas.  
     
     
         11 . The composition of  claim 7 , wherein the non-hydronepetalactone insect repellent is selected from the group consisting of: benzil, benzyl benzoate, 2,3,4,5-bis(butyl-2-ene) tetrahydrofurfural, butoxypolypropylene glycol, N-butylacetanilide, normal-butyl-6,6-dimethyl-5,6-dihydro-1,4-pyrone-2-carboxylate, dibutyl adipate, dibutyl phthalate, di-normal-butyl succinate, N,N-diethyl-meta-toluamide, dimethyl carbate, dimethyl phthalate, 2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-1,3-hexanediol, di-normal-propyl isocinchomeronate, 2-phenylcyclohexanol, p-methane-3,8-diol, and normal-propyl N,N-diethylsuccinamate.  
     
     
         12 . The composition of  claim 1  which is repellent to insects comprising biting insects, wood-boring insects, noxious insects, and household pest insects.  
     
     
         13 . The composition of  claim 1  which is repellent to mosquitoes.  
     
     
         14 . The composition of  claim 1  which has a skin surface evaporation rate of at least a minimum effective evaporation rate.  
     
     
         15 . The composition of  claim 1  which has a skin surface evaporation rate of at least a minimum effective evaporation rate for at least five hours.  
     
     
         16 . The composition of  claim 1  which is in the form of a cologne, a lotion, a spray, a cream, a gel, an ointment, a bath or shower gel, a foam product, makeup, a deodorant, shampoo, a hair lacquer or rinse or a personal soap.  
     
     
         17 . The composition of  claim 1  which is in the form of an insect repellent article of manufacture.  
     
     
         18 . The article of  claim 17  which is applied to a human or animal host.  
     
     
         19 . The article of  claim 17  which is selected from the group consisting of air freshener, a candle, a scented articles, a fiber, a sheets, cloth, paper, paint, ink, clay, wood, furniture, carpeting, sanitary goods, a plastic, and a polymer.  
     
     
         20 . A process for fabricating an insect repellent composition or an insect repellent article of manufacture, comprising providing as the composition or article, or incorporating into the composition or article, a diihydronepetalactone, or a mixture of dihydronepetalactone stereoisomers, represented by the general formula:  
       
         
           
           
               
               
           
         
       
     
     
         21 . A method of imparting, augmenting or enhancing the insect repellent effect of an article, comprising the step of incorporating into the article a diihydronepetalactone, or a mixture of dihydronepetalactone stereoisomers, represented by the general formula:  
       
         
           
           
               
               
           
         
       
     
     
         22 . A method according to  claim 20  wherein the dihydronepetalactone stereoisomers are (9S)-dihydronepetalactone stereoisomers derived from (7S)-nepetalactones.  
     
     
         23 . A method according to  claim 20  wherein the article is selected from the group consisting of a cologne, a lotion, a spray, a cream, a gel, an ointment, a bath or shower gel, a foam product, makeup, a deodorant, shampoo, a hair lacquer or rinse, a personal soap composition, air freshener, a candle, a scented article, a fiber, a sheet, cloth, paper, paint, ink, clay, wood, furniture, carpeting, sanitary goods, a plastic, and a polymer.  
     
     
         24 . A method according to  claim 23 , wherein the article is applied to a human or animal host.  
     
     
         25 . A method of repelling insects comprising exposing the insects to a diihydronepetalactone, or a mixture of dihydronepetalactone stereoisomers, represented by the general formula:  
       
         
           
           
               
               
           
         
       
     
     
         26 . The use of a diihydronepetalactone, or a mixture of dihydronepetalactone stereoisomers, represented by the general formula:  
       
         
           
           
               
               
           
         
       
       as an insect repellent.