Patent GB-950735-A (GB)
Title: Chloroalkyl sulfoxides, their preparation and insect combatting compositions
Inventor: LOUTHAN RECTOR PHILLIP
IPC: C07D209/76
Filed: 1960-04-22
Abstract: The invention comprises a sulphoxide having the formula: <FORM:0950735/C2/1> wherein R2 is n-octyl, sec-octyl, or a tert-octyl radical and R1 is H or CH3.  The novel compounds are made by oxidizing the corresponding sulphides with an oxidizing agent to form said sulphoxide.  The preferred oxidizing agents are hydrogen peroxide and organic peracids in a mole ratio of peroxygen compound to sulphide of 0.5:1 to 1.5:1 at temperatures in the range of 0 to 100 DEG C. Suitable solvents are methanol, ethanol, isopropanol and acetone. Alternatively the sulphides may be oxidized with oxygen or an oxygen-containing gas such as air, preferably with the addition of NO2 or concentrated nitric acid with a bromine-containing compound. Alkylene oxides may be present during the oxidation and are effective in stabilizing the sulphoxides during storage. The sulphide starting materials of the formula Cl.CH2.CH(R1)CH2-S-R2, where R1 and R2 are as defined above, may be made by reacting an octene with 3-chloropropyl mercaptan or its 2-methyl derivative usually in a mole ratio between 0.5:1 to 2.1 in the presence of U.V. light. Alternatively, an octyl mercaptan may be reacted with allyl chloride at -50 to 200 DEG C. in a mole ratio between 0.5:1 and 2.1 in the presence of U.V. light. The sulphide may also be made by reacting an octyl mercaptan in methanol with alkali metal hydroxide to form a mercaptide which is reacted with 1-bromo -3- chloropropane or its 2-methyl derivative. N-alkyl imides of bicyclo-[2.2.1] -5- heptene -2, 3-dicarboxylic acid can be made by condensing cyclopentadiene with maleic anhydride dissolved in benzene at room temperature, and reacting the condensation product with the appropriate alkyl amine. In examples, (1) n-octyl mercaptan is reacted with allyl chloride forming 3-chloropropyl n-octyl sulphide which is oxidized with aqueous hydrogen peroxide to 3-chloropropyl n-octyl sulphoxide; (2) allyl chloride reacts with an alkylene oxide and hydroxysulphide forming 3-chloropropyl mercaptan (with 3, 31-dichloro-dipropyl sulphide by-product), the mercaptan reacts with octene -1 to give 3-chloropropyloctyl sulphide which is oxidized by hydrogen peroxide to 3-chloropropyl n-octyl sulphoxide; (3) sec-octyl mercaptan and allyl chloride form 3-chloropropyl sec-octyl sulphide which is oxidized by H2O2 to 3-chyloropropyl sec-octyl-sulphoxide; (4) tert.-octyl mercaptan in methanolic NaOH reacts with 1-bromo -3- chloro-propane forming 3-chloropropyl t-octyl sulphide which is oxidized to 3-chloropropyl t-octyl sulphoxide; (VI) methallyl chloride reacts with n-octyl mercaptan forming 3-chloro -2- methyl propyl n-octyl sulphide which was oxidized by H2O2 to 3-chloro -2- methylpropyl n-octyl sulphoxide.ALSO:An insect repellent composition comprises a sulphoxide of general formula <FORM:0950735/A5-A6/1> wherein R1 is H or CH3 and R2 is n-octyl, sec-octyl or tert-octyl and a carrier.  An alylene oxide may be present as a stabilizer.  The repellancy of the sulphoxide may be enhanced by incorporating an N-alkyl imide of bicyclo-[2,2,1] - 5 - heptene - 2,3 - dicarboxylic acid.  The compositions may also contain at least one compound of the formula <FORM:0950735/A5-A6/2> wherein R2, R3, R4 and R5 are hydrogen or alkyl radicals, the total number of carbon atoms in all four radicals not exceeding 4.  A synergistic material such as silica gel may also be present.  The compositions may also contain insecticides. Suitable solvents include naphtha, kerosene, deodorized kerosene, toluene, xylene, cyclohexanone, acetone or an isoparaffinic hydrocarbon bp 260-800 DEG  F.  The compositions may be employed as solutions, emulsions, dusts, wettable powders or aerosols.