Patent GB-584793-A (GB)
Title: Manufacture of new nitrothioethers
Filed: 1944-01-19
Abstract: New nitrothioethers and nitromercaptans of the general formula R3(SCRR1.CHR2.NO2)n, wherein R, R1 and R2 may be the same or different and may be hydrogen, straight or branched chain saturated aliphatic hydrocarbon radicals, substituted or unsubstituted aryl radicals or heterocyclic radicals or where either R or R1 together with R2 may form part of a cycloaliphatic ring, wherein n is 1 or 2 and wherein R3 may be a mono- or di-valent (according as n is 1 or 2) substituted or unsubstituted hydrocarbon radical or it may (when n is 1) be hydrogen, are prepared by interacting a D a -nitro-olefine of the general formula CRR1=CR2NO2 with a compound of the general formula R3(SH)n, the symbols having the above significance, the reaction being carried out, if desired, in the presence of a basic substance.  Nitro-olefines which may be employed include nitro-ethylene, 1-nitropropene, 2-nitropropene, 2-nitro-2-butene, 1-nitrocyclohexene, 1-nitro-2-methyl-propene-1, 2-nitro-4-methyl-2-pentene, 1 - nitro - 2 - furylethylene, 1 - nitro - 1 - phenyl - ethylene, 2 -nitro - 1 - phenylethylene, 2 - nitro - 2 - methyl - 1 - phenylethylene, 1 - nitro - 2 - (41 - methoxyphenyl) ethylene, 1-nitro-2-(41-chlorophenyl) ethylene, 1-nitro-2-(41-bromophenyl) ethylene, 1-nitro-2-(41-methylphenyl) ethylene, 1 - nitro - 2 - (31 : 41 - methylenedioxyphenyl) ethylene, 1-nitro-2-(21-methylphenyl) ethylene and 1-nitro-2-a -naphthylethylene; there may also be used those alcohols which may be regarded as formed by hydration of the nitroolefines, viz. alcohols of the formula HOCRR1. CHR2NO2, wherein R, R1 and R2 have the significance given above, for example, nitrotert-butanol and mineral and organic acid esters of these alcohols, for example, b -nitroethyl nitrate.  The other starting materials, of the general formula R3(SH)n include hydrogen sulphide, methyl mercaptan, ethyl mercaptan, n- and sec.-butyl mercaptan, allyl mercaptan, ethylene dimercaptan, thiophenol, p-thiocresol, b -thionaphthol, thioglycollic acid, cyclo-pentyl mercaptan, dithioresorcinol, toluene-3-4-dithiol and 1-chlorobenzene-3 : 4-dithiol.  The reaction is brought about by heating a mixture of the two reactants, conveniently in the presence of an organic solvent such as ethanol, methanol or benzene.  The addition of a basic substance is desirable when a mercaptan is one of the reactants, but not when hydrogen sulphide is employed; however, it is desirable in all cases where, instead of a nitro-olefine, a compound giving rise to a nitro-olefine as described above, is employed.  Suitable basic substances are alkali metal hydroxides and alkoxides, quarternary ammonium hydroxides, for example benzyl trimethyl ammonium hydroxide and organic bases such as dimethylamine, pyridine and piperidine.  An amount of the mercaptan, in excess of that theoretically required to react in equivalent proportions with all the D a -nitroolefine, is employed to avoid the formation of dinitro-thioethers as by-products resulting from interaction of the nitrothioethers of the present invention with some of the nitro-olefine in the manner described in Specification 584,789. Similarly, in the reaction of the nitro-olefine with hydrogen sulphide, the nitro-mercaptans obtained may undergo further reaction as mercaptans according to the present invention with the nitro-olefines to form dinitrothioethers.  The products of the invention are isolated from the reaction mixture (after acidification if a basic substance has been used) by distillation or extraction with a solvent such as ether.  The products and the amines to which they give rise on reduction are useful intermediates in the preparation of dyestuffs and medicinal substances.  In examples: (1) 2-nitro-2-butene is added drop-wise at 0-5 DEG  C. to a solution of methyl mercaptan and sodium methoxide in methanol to give methyl 2-nitro-1-methyl propyl sulphide; similarly, 2-nitro-propylene and methyl mercaptan yield methyl 2-nitropropyl sulphide, n-butyl mercaptan and 2-nitropropylene yield n-butyl 2-nitropropyl sulphide, thiophenol and 1-nitro-propylene yield phenyl 2 - nitro - isopropyl sulphide, methyl mercaptan and o -nitro-styrene yield methyl 1-phenyl-2-nitroethyl sulphide, dithioresorcinol and 1-nitro-2-methyl - 1 - propene yield dithioresorcinol di-(nitro-tert.-butyl) ether which on oxidation with hydrogen peroxide gives the corresponding disulphone, and methyl mercaptan and b -nitro-ethyl nitrate yield methyl-2-nitroethyl sulphide; (2) 2-nitropropylene is heated with n-butyl mercaptan to give n-butyl-2-nitropropyl sulphide; (3) thioglycollic acid dissolved in an ethanol solution of sodium ethoxide is reacted with 2-nitro-2-butene to yield carboxymethyl - 2 - nitro - 1 - methylpropyl sulphide; (4) a mixture of n-butyl mercaptan nitro-tert.-butanol and piperidine is allowed to stand at room temperature for three days and n-butyl nitro-tert.-butyl sulphide is obtained on acidifying and extracting with ether; (5) nitroethylene is reacted with a saturated solution of hydrogen sulphide in ethanol to yield b -nitroethyl mercaptan and b b 1-dinitrodiethyl sulphide; (6) 1-nitro-2-methyl-1-propene is reacted as in (5) above to give nitro-tert.-butyl mercaptan, and 2 - nitro - 1 - phenyl ethylene similarly treated gives b b 1-dinitro-a  : a 1-diphenyl diethyl sulphide; (7) b -nitroethyl nitrate is reacted with a methanol solution of potassium sulphide to yield b b 1-dinitro-diethyl sulphide and with a methanol solution of potassium hydrosulphide to yield b -nitroethyl mercaptan. 2-nitro-4-methyl-2-pentene is prepared by the condensation of isobutyraldehyde with nitroethane, in the presence of piperidine and dehydration of the resulting alcohol.