Patent Application: US-5796008-A

Abstract:
this invention relates to compositions of one or more compounds that incorporate one or more allyl sulfide , allyl disulfide or allyl polysulfide moieties , or one or more allyl sulfide , allyl disulfide or allyl polysulfide moieties and one or more hydroxyl groups , used in effective amount in formulations , including emulsions , to repel blood - feeding ectoparasitic arthropods , including mosquitoes , and to deter them from landing and feeding when applied to the skin , clothing or environment of animals , including humans . said compounds can include , but are not limited to , 8 - allyl - sulfanyloctan - 1 - ol . this invention also relates to compositions comprising one or more of said compounds in further combination with other arthropod repellent and deterrent compounds , including vanillin . these compounds may be formulated with inert ingredients to form a liquid , gel , paste , soap , spray , aerosol or powder .

Description:
past research and practice has demonstrated that garlic , allium sativum , and preparations therefrom , can be repellent to mosquitoes and other blood - feeding ectoparasitic arthropods . one study claims that allyl sulfide in combination with vitamin b 1 causes repellence of fleas when ingested by dogs , but neither vitamin b 1 nor garlic oil ( erroneously assumed to be composed solely of allyl sulfide ) was effective alone , and repellence caused directly by the blend was never demonstrated . in contrast to this prior art , we have discovered unexpectedly that repellence of blood - feeding ectoparasitic arthropods , and deterrence of landing and feeding by such arthropods , is imparted by the presence of one or more allyl sulfide , allyl disulfide or allyl polysulfide moieties in various compounds found in garlic oil . we have further discovered unexpectedly that synthetic molecules not found in garlic oil , but incorporating one or more of these moieties in their molecular structure , can have repellent and deterrent properties in excess of those imparted by compounds that occur naturally in garlic or garlic oil . of particular interest for repellent and deterrent properties is the family of compounds comprising aliphatic alcohols with an allylsulfide moiety , including the novel compound 8 - allylsulfanyloctan - 1 - ol . in accordance with these discoveries , it is an object of this invention to provide methods and compositions that may be used in protecting animals , including humans , from vectored disease - causing pathogens , and from biting and annoyance caused by mosquitoes and other blood - feeding ectoparasitic arthropods . the black - eyed liverpool strain of aedes . aegyti was obtained from dr . carl lowenberger , simon fraser university ( sfu ). insects were reared under standardized conditions ( 60 - 70 % relative humidity , 26 - 28 ° c ., 14 h light : 10 h dark photoperiod ) in sfu &# 39 ; s insectary . neonate larvae that hatched in glass dishes of sterilized hypoxic water were transferred to trays of distilled water provisioned with nutrafin ® basix staple food fish diet . pupae were collected daily and separated by sex , and 15 females and 10 males were placed in a paper cup ( 7 . 5 cm diameter , 8 . 5 cm high ) with a mesh lid . emergent adults were fed a 10 % ( w / v ) sucrose solution via braided cotton dental rolls . arm - fed gravid females were offered water - containing paper cups , lined with paper - towel as an oviposition substrate . the ifakara strain of anopheles gambiae was obtained from dr . bernard roitberg , sfu . insects were reared under standardized conditions ( see above ) in sfu &# 39 ; s insectary . neonate larvae that hatched in glass dishes of distilled water were transferred to trays ( 250 - 500 larvae / tray ) of distilled water , and provisioned with fish diet ad libitum ( see above ). pupae were collected and separated daily and placed in a paper cup with a mesh lid ( 30 - 45 pupae / cup ). emergent adults were fed a 10 % ( w / v ) sucrose solution via braided cotton dental rolls . ann - fed gravid females were offered a water - containing dish ( 9 cm diameter ) with moistened filter paper as an oviposition substrate . culex quinquefasciatus were obtained from erin vrzal of the united states department of agriculture ( usda ), gainesville , fla . insects were reared in sfu &# 39 ; s quarantine facility at 40 - 50 % relative humidity , 25 - 27 ° c ., and a photoperiod of 14 h light and 10 h dark . neonate larvae that hatched in glass dishes of distilled water were transferred to trays ( 250 - 500 larvae / tray ) of distilled water , and provisioned with fish diet ad libitum ( see above ). pupae were collected and separated daily and placed in a paper cup with a mesh lid ( 30 - 45 pupae / cup ). emergent adults were fed a 10 % ( w / v ) sucrose solution via braided cotton dental rolls . ann - fed gravid females were offered a water - containing dish for oviposition . candidate repellents and deterrents were bioassayed according to a modified protocol from the world health organization ( 1996 ). at least 1 hour prior to each bioassay , 75 host - seeking non blood - fed , nulliparous , 5 - to 8 - day - old female aedes aegypti , anopheles gambiae or culex quinquefasciatus were placed into a wood - framed cage ( 26 . 5 cm on each side and 42 . 5 cm high ) with a wooden floor , screened mesh sides and top , and a clear acrylic front fitted with a cotton stockinette sleeve ( 10 cm diameter ). the test subject &# 39 ; s arm was covered with an elbow - length polyethylene glove with an excised patch ( 16 . 6 cm long , 6 cm wide ) to expose the ventral forearm of the test subject . candidate deterrents were formulated in mineral ( paraffin ) oil and applied to the exposed forearm 5 min prior to inserting the arm into the cage . the inserted arm remained in the cage for 3 min every 30 min . prior to each 3 - min bioassay period , the hand of the untreated arm was inserted into the cage to ascertain that it received 10 bites within 30 sec as an indication of “ biting pressure ”. the bioassay was terminated when the treated arm received ≧ 2 bites in one 3 - min bioassay period or one bite in each of two consecutive bioassay periods . the time elapsed from experiment initiation to first bite was recorded as deterrent failure or complete protection time . percentage repellency at the time the deterrent failed to protect the exposed forearm was calculated by the equation ( c − t )/ c × 100 , where c and t represent the numbers of mosquitoes landing on and / or biting the control and treatment arm , respectively ( tawatsin et al . 2001 ). n , n - diethyl - m - toluamide formulated in ethanol at a corresponding dose served as a positive control , and mineral oil by itself served as a negative control . on each day , only one candidate compound was tested , ensuring that any residual material in the chamber had disappeared before the next bioassay . garlic oil ( allium sativum — mexico ; clearwater soap works , box 1775 rr1 , clearwater , bc v0e 1n0 , canada ) was formulated in mineral oil and tested using the general bioassay procedure described in example 2 at a dose of 0 . 1 mg per cm 2 of arm surface . it expressed repellence and deterrence for ˜ 30 min . aliquots of garlic oil extracts were then subjected to coupled gas chromatographic - electroantennographic detection ( gc - ead ) analysis . fourteen components ( 10 shown in fig1 ) elicited responses from female or male mosquito antennae . some of these components were isolated by high - performance liquid chromatography ( hplc ) for identification by nuclear magnetic resonance spectroscopy ( nmr ). other components were identified ( compounds 11 - 14 in table 2 ) by coupled gc - mass spectrometry and by retention index calculations . assignment of molecular structure for an antennal stimulatory constituent was confirmed by comparing its gc retention time and mass spectrum with that of an authentic standard that was purchased or synthesized . four of the 10 components in fig1 were tentatively identified by comparing their mass spectra and retention indices with those reported in the literature ( block et al . 1998 ). some of the 10 components in fig1 were bioassayed singly ( see general bioassay procedure ) and in various combinations , all of which were as deterrent to mosquitoes as garlic oil . to determine the most deterrent component ( s ) in garlic oil , it was fractionated by hplc into four fractions , each containing one or more of the ead - active components ( compounds 1 - 10 in fig1 and 11 - 14 in table 2 ). each fraction was then bioassayed and shown to be similarly effective in repelling and deterring mosquitoes . components with high molecular weight (& gt ; 250 daltons ) are advantageous in that they : 1 ) dissipate slowly from treated surfaces ; 2 ) provide long - lasting protection against mosquitoes and 3 ) convey little , if any , offensive smell . the relative abundance of such components was enhanced by treating garlic oil under vacuum , thus stripping away lower - boiling components . in gc - ead analyses of the high - boiling residue , four components elicited responses from mosquito antennae . they were identified as 4 , 5 , 9 , 10 - tetrathiatrideca - 1 , 12 - diene , 6 - methyl - 4 , 5 , 8 , 9 - tetrathiadodeca - 1 , 11 - diene , 2 -( 2 , 3 - dithia - 5 - hexenyl )- 3 , 4 - dihydro - 2 ( h )- thiopyran and 3 -( 2 , 3 - dithia - 5 - hexenyl )- 3 , 4 - dihydro - 2 ( h )- thiopyran ( block et al . 1998 ) ( compounds 11 - 14 in table 2 ), and shown to have a strong repellent and deterrent effect in bioassays . to determine the part of the molecule responsible for deterrence , we synthesized compounds 15 - 24 ( table 2 ). synthesis of 8 - allylsulfanyloctan - 1 - ol ( compound 24 in table 2 ) is described as an example of the preparation of new semiochemical repellents ( see fig2 ). 1 , 8 - octanediol ( a ) was purchased from alfa aesar and was converted in a 1 - step synthesis to 8 - bromo - 1 - octanol ( b , 60 - 70 % yield ) by continuous liquid - liquid extraction with n - heptane and 48 % aqueous hydrobromic acid . by maintaining the aqueous level at ambient temperature , alcohol b was produced with & gt ; 99 % purity . warming the aqueous layer to 50 - 55 ° c . accelerated the reaction by & gt ; 10 times but increased the by - product 1 , 8 - dibromooctane from 0 . 6 % to 1 . 8 - 2 . 0 %. after removal of heptane in vacuo , alcohol b was used as is . alcohol b ( 9 . 7 g , 46 . 4 mmol ) was stirred with thiourea ( 4 . 0 g , 52 . 6 mmol ) in 95 % ethanol ( 150 ml ). the mixture was refluxed for 6 h to allow formation of the isothiuronium salt c that was not isolated . to this mixture , 5 . 6 g of koh pellets were added in one portion . after another 2 . 5 h of reflux , the mixture was cooled to room temperature and , without isolating thio - alcohol d or its potassium salt , 6 ml of allyl chloride ( 73 mmol ) were added in one portion . after stirring the reaction mixture overnight , water ( 150 ml ) and a 1 : 1 mixture of ether / hexane ( 200 ml ) were added . products were extracted , and the organic phase was washed with water and brine , and dried ( anh . mgso 4 ). solvents were removed in vacuo , and the crude reaction mixture was filtered through silica ( 25 g ), using in sequence hexane and a 1 : 1 mixture of hexane - ether as eluents to remove non - polar impurities , such as diallyldisulfane , and to obtain desired 8 - allylsulfanyl - octan - 1 - ol ( e ). the yield of e (& gt ; 99 % pure based on gas chromatography ) was 8 . 1 g ( 40 . 0 mmol , 86 . 2 %). the following mass spectrometric fragmentation ions [ m / z ( relative abundance )] of e were obtained : 203 ( m + 1 , 28 ), 202 ( m , 53 ), 143 ( 50 ), 142 ( 17 ), 131 ( 53 ), 101 ( 23 ), 87 ( 100 ), 85 ( 26 ), 81 ( 24 ), 79 ( 15 ), 74 ( 66 ), 73 ( 23 ), 69 ( 32 ), 68 ( 17 ), 67 ( 73 ), 59 ( 28 ), 55 ( 51 ), 53 ( 15 ), 47 ( 15 ), 45 ( 48 ), 41 ( 91 ). nuclear magnetic resonance ( nmr ) data were as follows : 1 h nmr ( 600 mhz , cd 3 cn ): δ 1 . 20 - 1 . 40 ( m , 8h ), 1 . 45 ( m , 2h ), 1 . 53 ( m , 2h ), 2 . 43 ( m , 2h ), 3 . 11 ( dt , j = 7 . 2 , 0 . 9 hz , 2h ), 3 . 46 ( dt , j = 6 . 6 , 5 . 4 hz , 2h ), 5 . 05 ( tdd , j = 10 . 0 , 1 . 8 , 0 . 9 hz , 1h ) 5 . 08 ( m , 1h ), 5 . 78 ( tdd , j = 17 . 0 , 10 . 0 , 7 . 2 hz , 1h ). 13 c nmr ( cd 3 cn ): δ 26 . 9 , 29 . 8 , 30 . 2 , 30 . 3 , 30 . 4 , 31 . 4 , 33 . 9 , 35 . 2 , 62 . 8 , 117 . 3 , 136 . 4 . in bioassays , neither compound 20 ( the sulfur atoms replaced by an oxygen atoms ) nor compound 21 ( containing no hetero atoms ) had any repellence or deterrence . furthermore , taking other results in table 2 and in fig1 into account , there is compelling evidence that repellence and deterrence is expressed by molecules with one or more allyl sulfide , allyl disulfide , or allyl polysulfide moieties . further repellence and deterrence can be obtained by combining in the same compound one or more allyl sulfide , allyl disulfide or allyl polysilfide moieties with one or more hydroxyl moieties . a compound with commercial appeal should be 1 ) odorless , 2 ) stable , 3 ) easy and inexpensive to synthesize , 4 ) non - toxic , and 5 ) deterrent for a long time . compound 24 ( table 2 ) appears to meet all these requirements . it has almost no detectable odor and it is very potent , even at a low dose . to determine the repellence and deterrence of 8 - allylsulfanyloctan - 1 - ol against aedes aegypti , a 5 %, 10 % or 25 % formulation of 8 - allylsulfanyloctan - 1 - ol in mineral oil was applied in experiments 1 - 3 at a dose of 1 . 5 mg ( total composition ) per cm 2 to the skin of the test person , and was bioassayed according to the protocol described under example 2 . in experiment 4 , mineral oil by itself served as a negative control and was bioassayed at the same dose ( 1 . 5 mg per cm 2 ) as in experiments 1 - 3 . each of experiments 1 - 4 was replicated four times . in experiments 1 , 2 and 3 , 5 %, 10 % and 25 % formulations of 8 - allylsulfanyl - octan - 1 - ol in mineral oil provided protection from bites by aedes egypti on average for 52 min , 157 min and 305 min , respectively ( fig3 ). in experiment 4 , mineral oil by itself failed to provide any protection from bites ( fig3 ). to determine the repellence and deterrence of 8 - allylsulfanyloctan - 1 - ol against anopheles gambiae , a 2 %, 5 % or a 10 % formulation of 8 - allylsulfanyloctan - 1 - ol in mineral oil was applied in experiments 5 - 7 at a dose of 1 . 5 mg per cm 2 to the skin of the test person , and was bioassayed according to the protocol described under example 2 . in experiment 8 , mineral oil by itself served as a negative control and was tested at the same dose ( 1 . 5 mg per cm 2 ) as in experiments 5 - 7 . each of experiments 5 - 8 was replicated 4 times . in experiments 5 , 6 and 7 , 2 %, 5 % and 10 % formulations of 8 - allylsulfanyloctan - 1 - ol in mineral oil provided protection from bites by anopheles gambiae on average for 297 min , 314 min and 487 min , respectively ( fig4 ). in experiment 8 , mineral oil by itself failed to provide appreciable protection ( fig4 ). to determine the repellence and deterrence of 8 - allylsulfanyloctan - 1 - ol against culex quinquefasciatus , a 2 % and 5 % or a 10 % formulation of 8 - allylsulfanyloctan - 1 - ol in mineral oil was applied in experiments 9 - 11 at a dose of 1 . 5 mg per cm 2 to the skin of the test person , and was bioassayed according to the protocol described under example 2 . in experiment 12 , mineral oil by itself served as a negative control and was tested at the same dose ( 1 . 5 mg per cm 2 ) as in experiments 9 and 10 . each of experiments 9 - 11 was replicated 4 times . in experiments 9 , 10 and 11 , 2 %, 5 % and 10 % formulations of 8 - allylsulfanyloctan - 1 - ol in mineral oil provided protection from bites by culex quinquefasciatus on average for 198 min , 319 min , and 495 min , respectively ( fig5 ). in each of the three replicates in experiment 11 , there was complete protection against bites when the experiment was terminated after eight hours . thus , the protection time is even greater than illustrated conservatively in fig5 . in experiment 12 , mineral oil by itself failed to provide appreciable protection ( fig5 ). comparison of repellence and deterrence caused by n , n - diethyl - m - toluaniide and by 8 - allylsulfanyloctan - 1 - ol against anopheles gambiae to be able to compare the repellence and deterrence caused n , n - diethyl - m - toluamide ( deet ), and by 8 - allylsulfanyloctan - 1 - ol , experiment 13 tested a 2 % formulation of n , n - diethyl - m - toluamiide in ethanol ( the best formulant for this compound ) for protection from bites by anopheles gambiae . a dose of 1 . 5 mg per cm 2 was applied to the skin of the test person and bioassayed according to the protocol described under example 2 . in experiment 13 , a 2 % formulation of n , n - diethyl - m - toluamide provided protection from bites by anopheles gambiae on average for 66 min ( fig6 ). unexpectedly , and in contrast , the duration of protection provided by n , n - diethyl - m - toluamide was only one sixth of the 297 min protection provided by a 2 % formulation of 8 - allylsulfanyl - octan - 1 - ol in experiment 5 ( fig6 ; see also fig4 ). the components , amounts and proportions of emulsion no . 1 were : distilled water 0 . 35 g , 23 %; light paraffin oil ( emd chemicals ) 0 . 53 g , 35 %; glycerol ( anachemia ) 0 . 27g , 18 %; soy lecithin ( xenex labs ) 0 . 21 g , 14 %; 8 - allylsulfanyloctan - 1 - ol 2 . 0 - 6 . 7 % ( if added ); ethanol 0 . 05 ml ( quickly evaporating and not remaining as part of the emulsion ); vanillin ( bdh laboratory chemicals ) 2 . 0 - 6 . 7 % ( if added ). according to amounts of the active ingredients 8 - allylsulfanyloctan - 1 - ol and vanillin , the percentage of other constituents was slightly adjusted accordingly . a vessel was charged with water , glycerol , paraffin oil , soy lecithin , and 8 - allylsulfanyl - octan - 1 - ol ( if added ) in the above order and mixed to homogeneity after each addition . if vanillin was added , a second vessel was charged with ethanol and vanillin , stirring the mixture until vanillin was completely dissolved ; the vanillin solution was then added to the first vessel and vortexed for several minutes to achieve homogeneity . if vanillin was not added , ethanol was added to the first vessel and vortexed for several minutes to achieve homogeneity . the components , amounts and proportions of emulsion no . 2 were : structure zea ( hydroxypropyl cellulose ) ( national starch and chemical co .) 0 . 16 g , 4 %; distilled water 2 . 56 g , 63 %; glycerol ( sigma - aldrich ) 0 . 21 g , 5 %; stepanquat ml [ methyl sulfate quaternary ammonium salt of the esterification of oleic acid with n , n , n ′, n ′- tetrakis ( 2 - hydroxypropyl ) ethylene - diamine ] ( stepan co .) 0 . 12 g , 3 %; isopropanol ( anachemia ) 0 . 21 g , 5 %; lipocol l ( lipo chemicals inc .) 0 . 06 g , 2 %; 8 - allylsulfanyloctan - 1 - ol 0 . 41 g , 10 %; and vanillin ( sigma - aldrich ) 0 . 32 g , 8 %. structure zea was charged into a vessel , water was added , and the components were mixed to homogeneity . a second vessel was charged with the glycerol , the stepanquat ml , the isopropanol , the lipocol l , 8 - allylsulfanyloctan - 1 - ol , and vanillin in the above order . after each addition , the resulting mixture was stirred for several minutes . the water / structure zea homogenate was then added slowly to the rapidly mixing organic mixture over several minutes . after mixing was completed , the gross emulsion was homogenized @ 30 , 000 rpm for several minutes . test of emulsion no . 1 compositions with 8 - allylsulfanyloctan - 1 - ol and vanillin against aedes aegypti to compare the repellence and deterrence against aedes aegypti caused by 8 - allylsulfanyloctan - 1 - ol as a single active ingredient and by 8 - allylsulfanyloctan - 1 - ol in combination with vanillin as a second active ingredient , we tested a 6 . 7 % emulsion of vanillin ( experiment 14 ), a 6 . 7 % emulsion of 8 - allylsulfanyloctan - 1 - ol ( experiment 15 ), and a 13 . 4 % emulsion of 8 - allylsulfanyloctan - 1 - ol plus vanillin ( 1 : 1 ratio ) ( experiment 16 ). 8 - allylsulfanyloctan - 1 - ol and vanillin were formulated in emulsion no . 1 ( see example 9 ). in each of experiments 13 - 15 , test stimuli were applied at a dose of 1 . 5 mg per cm 2 to the skin of the test person , and were bioassayed according to the protocol described under example 2 . in experiment 17 , emulsion no . 1 served as a positive control and was tested at the same dose ( 1 . 5 mg per cm 2 ) as in experiments 14 - 16 . in experiments 14 , 15 and 16 , vanillin , 8 - allylsulfanyloctan - 1 - ol , and 8 - allylsulfanyl - octan - 1 - ol plus vanillin provided protection from bites by aedes aegypti on average for 44 min , 77 min and 330 min , respectively ( fig7 ). these results indicate that there is an unexpected synergistic interaction between 8 - allylsulfanyloctan - 1 - ol and vanillin . in experiment 17 , emulsion no . 1 composition by itself failed to provide any protection ( fig7 ). test of emulsion no . 1 compositions with 8 - allylsulfanyloctan - 1 - ol and vanillin against anopheles gambiae to compare the repellence and deterrence against anopheles gambiae caused by 8 - allyl - sulfanyloctan - 1 - ol as a single active ingredient and by 8 - allylsulfanyloctaii - 1 - ol in combination with vanillin as a second active ingredient , we tested a 6 . 7 % emulsion of vanillin ( experiment 18 ), a 6 . 7 -% emulsion of 8 - allylsulfanyl - octan - 1 - ol ( experiment 19 ) and a 13 . 4 % emulsion of 8 - allylsulfanyloctan - 1 - ol plus vanillin ( 1 : 1 ratio ) ( experiment 20 ). 8 - allylsulfanyloctan - 1 - ol and vanillin were formulated in emulsion no . 1 ( see example 9 ). in each of experiments 18 - 20 , test stimuli were applied at a dose of 1 . 5 mg per cm 2 to the skin of the test person , and were bioassayed according to the protocol described under example 2 . in experiment 21 , emulsion no . 1 served as a positive control and was tested at the same dose ( 1 . 5 mg per cm2 ) as in experiments 18 - 20 . each of experiments 18 - 21 was replicated three times . in experiments 18 - 21 , vanillin , 8 - allylsulfanyloctan - 1 - ol and 8 - allylsulfanyloctan - 1 - ol plus vanillin provided protection from bites by anopheles gambiae on average for 110 min , 369 min and 462 min , respectively ( fig8 ). in two of the three replicates in experiment 20 , there was complete and unexpected protection against bites for eight hours , after which the experiment was terminated . thus , the protection time is even greater than illustrated conservatively in fig8 . the results indicate that there is an interactive effect between 8 - allylsulfanyloctan - 1 - ol and vanillin . in experiment 21 , emulsion no . 1 by itself failed to provide appreciable protection ( fig8 ). test of emulsion no . 1 compositions with 8 - allylsulfanyloctan - 1 - ol and vanillin against culex quinquefasciatus to compare the repellence and deterrence against culex quinquefasciatus caused by 8 - allylsulfanyloctan - 1 - ol as a single active ingredient and by 8 - allylsulfanyloctan - 1 - ol in combination with vanillin as a second active ingredient , we tested a 6 . 7 % emulsion of vanillin ( experiment 22 ), a 6 . 7 % emulsion of 8 - allylsulfanyloctan - 1 - ol ( experiment 23 ) and a 13 . 4 % emulsion of 8 - allylsulfanyloctan - 1 - ol plus vanillin ( 1 : 1 ratio ) ( experiment 24 ). 8 - allylsulfanyloctan - 1 - ol and vanillin were formulated in emulsion no . 1 ( see example 9 ). in each of experiments 21 - 24 , test stimuli were applied at a dose of 1 . 5 mg per cm 2 to the skin of the test person , and were bioassayed according to the protocol described under example 2 . in experiment 25 , emulsion no . 1 served as a positive control and was tested at the same dose ( 1 . 5 mg per cm 2 ) as in experiments 22 - 24 . each of experiments 22 - 25 was replicated three times . in experiments 22 - 24 , vanillin , 8 - allylsulfanyloctan - 1 - ol and 8 - allylsulfanyloctan - 1 - ol plus vanillin provided protection from bites by culex quinquefasciatus on average for 88 min , 242 min and 286 min , respectively ( fig9 ). these results indicate that there is an interactive effect between 8 - allylsulfanyloctan - 1 - ol and vanillin . in experiment 25 , emulsion no . 1 by itself failed to provide any protection ( fig9 ). comparison of deterrence against aedes aegypti caused by n , n - diethyl - m - toluamide in ethanol and by 8 - allylsulfanyloctan - 1 - ol plus vanillin in compositions formulated in emulsions no . 1 or no . 2 to be able to compare the repellence and deterrence caused by n , n - diethyl - m - toluamide and by 8 - allylsulfanyloctan - 1 - ol plus vanillin in emulsion no . 1 ( example 9 ), experiment 26 tested a 6 . 7 % formulation of n , n - diethyl - m - toluamide in ethanol ( the best formulant for deet ) for protection from bites by aedes egypti . in each replicate , a dose of 1 . 5 mg per cm was applied to the skin of the test person and bioassayed according to the protocol described under example 2 . in experiment 26 , n , n - diethyl - m - toluamide provided protection from bites by aedes aegypti on average for 197 min ( fig1 ). 8 - allylsulfanyloctan - 1 - ol ( 6 . 7 %) plus vanillin ( 6 . 7 %) in emulsion no . 1 provided protection on average for 333 min ( fig1 ). to be able to further compare the deterrence caused by n , n - diethyl - m - toluamide with that caused by 8 - allylsulfanyloctan - 1 - ol plus vanillin , experiment 27 tested a 10 . 4 % formulation of n , n - diethyl - m - toluamide in ethanol , and experiment 28 tested 8 - allylsulfanyloctan - 1 - ol ( 10 . 4 %) plus vanillin ( 7 . 9 %) in emulsion no . 2 ( example 10 ). in each replicate of both experiments , a dose of 1 . 5 mg per cm was applied to the skin of the test person and bioassayed according to the protocol described under example 2 . in experiment 28 , allylsulfanyloctan - 1 - ol plus vanillin in emulsion no . 2 provided protection from bites by aedes aegypti on average for 333 min , considerably longer than the 231 min on average provided by n , n - diethyl - m - toluamide in experiment 27 ( fig1 ). as will be apparent to those skilled in the art in the light of the foregoing disclosure , many alterations and modifications are possible in the practice of this invention without departing from the spirit or scope thereof . accordingly , the scope of the invention is to be construed in accordance with the substance defined by the following claims . anderson , w . a . and brock , b . e . 1998 . mosquito repelling technique . u . s . pat . no . 5 , 733 , 552 . arand , a . and arand , j . k . 2002 . garlic composition for foliar applications . u . s . pat . no . 6 , 488 , 950 . arand , a . and arand , j . k . 2003 . garlic composition for foliar applications . u . s . pat . no . 6 , 511 , 674 . beldock , d . t ., beldock , j . a ., and mudge , g . 1997 . insect repellent blends , lotions and sprays . u . s . pat . no . 5 , 621 , 013 . butler , j . f . 2001 . method for inhibiting from feeding , cockroaches . u . s . pat . no . 6 , 255 , 356 . cantrell , c . l ., klun , j . a ., and duke , s . o . 2006 . novel chlerodanes and methods for repelling arthropods . u . s . patent application publication no . us 2006 / 0235071 . fried , h . l ., khazan , d ., and morales , m . n . 2007 . environmentally safe insect repellent composition . u . s . pat . no . 7 , 201 , 926 . hallahan , d . l . 2007 . insect repellent compounds . u . s . pat . no . 7 , 232 , 844 . ishiwateri , t . 1999 . arthropod repellent and method for repelling arthropods . u . s . pat . no . 5 , 925 , 371 . mckenzie , j . 1995 . insect repellent for fruits , vegetables and plants . u . s . pat . no . 5 , 429 , 817 . nichols , l . d . 1993 . insect repellent compositions . u . s . pat . no . 5 , 206 , 022 . pijoan , m . and jachowski , l . a ., jr . 1950 . insect repellent mixtures comprising a hydrogenated diphenyl and a hydrogenated naphthol . u . s . pat . no . 2 , 512 , 675 . polefka , t . g ., ramachandran , p ., steltenkamp , r . j ., connors , t . f ., and kinscherf , k . m . 1997 . insect repelling compositions comprising mixtures of an n - 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