Patent GB-908638-A (GB)
Title: 2-pyridyl-1-oxido thio ethers, their manufacture and pesticidal compositions thereof
IPC: C07D213/89
Filed: 1959-07-28
Abstract: The invention comprises mono- or di-thioformals or acetals of 2-mercapto-pyridine-1-oxide having the general formula C5H4N(--> O)S.CHR1.AR. in the form of the free base or hydrohalide salt thereof, wherein R is a hydrogen atom or a hydrocarbon or halohydrocarbon radical containing 1 to 18 carbon atoms, R1 is a hydrogen atom or a lower alkyl or haloalkyl group containing 1 to 5 carbon atoms and A is oxygen or sulphur, with the proviso that when R is hydrogen, R1 is also hydrogen and A is oxygen.  The compounds, other than those wherein R and R1 are hydrogen and A is oxygen, are prepared by reacting 2-mercapto pyridine-1-oxide or a mercaptide thereof with a compound of the general formula XCHR1.AR11 wherein X is a halogen atom, R11 is a hydrocarbon or halohydrocarbon radical containing 1 to 18 carbon atoms and R1 and A are as defined above; suitable mercaptides include the sodium, potassium, ammonium and substituted ammonium salts. The other compounds wherein R and R1 are hydrogen and A is oxygen are prepared by reacting 2-mercapto pyridine-1-oxide or a mercaptide thereof with formaldehyde, which may be used in the paraformaldehyde form, in the presence of a hydrogen halide, the product being recovered in the form of the hydrohalide salt or free base.  Both reactions may be effected in the presence of solvents.  Examples describe the preparation of (1) S-(2-pyridyl-1-oxide)O-methyl mono thioformal, (2) S-(2-pyridyl-1-oxide)O-n-propyl mono thioformal, (3) S-(2-pyridyl-1-oxide)O-ethyl mono thio chloracetal, using a :b -dichloro ethyl ethyl ether, (4) S-hydroxy methyl-2-mercapto pyridine-1-oxide hydrochloride, (5) S-(2-pyridyl-1-oxide)O-n-dodecyl mono thioformal, (6) S-(2-pyridyl-1-oxide)O-ethyl mono thioformal, (7) S-(2-pyridyl-1-oxide)O-isopropyl monothioformal, (8) S-(2-pyridyl-1-oxide)O-n-octa decyl mono thio formal, (9) S-(2-pyridyl-1 - oxide)S1-methyl dithioformal, (10) S-(2-pyridyl - 1 - oxide)O - isooctyl monthioformal hydrochloride and (11) S-(2-pyridyl-1-oxide)S1-n-propyl dithioformal hydrochloride.  Other named products include S-(2-pyridyl-1-oxide) S1-4-chlorophenyl dithioformal, S-(2-pyridyl-1-oxide)S1-benzyl dithioformal, S-(2-pyridyl-1-oxide)O-ethyl mono thio acetal, S-(2-pyridyl-1-oxide)O-vinyl mono thio formal and S-(2-pyridyl-1-oxide)O-2-chlorethyl mono thio chloracetal. Various other values are given for R (e.g. o-bromo benzyl and cyclohexyl) and R1.  Reference is made to the hydro bromides of the products.  The compounds may be used in pesticidal compositions (see Group VI). Halo ethers used as starting materials may be obtained as described in Specification 744,454.ALSO:Pesticidal compositions comprise pyridine-1-oxide derivatives having the general formula <FORM:0908638/VI/1> or their hydrohalide salts, and a pesticidal carrier, R representing hydrogen or a hydrocarbon or halo-hydrocarbon radical containing 1 to 18 carbon atoms, R1 representing hydrogen or an alkyl or halo-alkyl radical containing 1 to 5 carbon atoms and A being oxygen or sulphur, with the proviso that when R is hydrogen, R1 is also hydrogen and A is oxygen. Specified pyridine compounds are those in which (1) A=O, R=hydrogen, methyl, ethyl, vinyl, propyl, dodecyl, iso-octyl or octadecyl and R1=H; (2) A=S, R=methyl, ethyl, parachlorophenyl, benzyl or propyl and R1=H; (3) A=O, R=C2H5 and R1=CH3; (4) A=O, R= Cl-CH2CH2- and R1=ClCH2-; (5) A=O, R=C2H5 and R1=ClCH2-.  Additional examples of R and R1 are given.  The pyridine compounes may be admixed with finely divided solids, e.g. calcium silicate, talc, bentonite and clay or may be dissolved or suspended in a liquid diluent, e.g. water, with optionally wetting agents or dispersants.  There may also be used as carriers other active agents, e.g. parasiticides herbicides and fertilizers.  The compositions normally comprise about 15 to 80% of the pyridine compounds and may be used to control fungi and weeds.  The hydrochlorides and hydrobromides of the pyridine compounds are mentioned.  Specification 744,454 is referred to.