Patent GB-962912-A (GB)
Title: Photographic silver halide emulsions of increased sensitivity and compounds suitable for increasing their sensitivity
IPC: C07D213/20
Filed: 1960-10-25
Abstract: Compounds of the general formula: <FORM:0962912/C1/1> where d is 1, 2 or 3, m and n are integers from 2-10, X is an anion and \sNQ is an organic group containing a quaternary nitrogen atom are prepared by oxidizing the corresponding quaternary ammonium sulphides with hydrogen peroxide in acetic acid or with hypochlorous acid.  The organic group \sNQ may be a pyridinium, picolinium, collidinium, N-methylpiperidinium, N-ethylpiperidinium or N-methylmorpholinium group joined to the (CH2)m group by the quaternary nitrogen atom, or it may be an N-alkylpyridinium group joined in the 4-position to the (CH2)m group and may contain methyl, ethyl or halogen substituents. Alternatively, the group \sNQ may be -\sNN.R2.R3.R4 (where R2, R3 and R4 are alkyl groups) such as a triethylammonium, diethyl-methyl ammonium, tri-n-propyl ammonium or diethyl-n-butyl ammonium group. The anion X may be perchlorate, p-toluene sulphonate, benzene sulphonate, methyl sulphate, ethyl sulphate or bromide. Reference also is made to compounds of the general formula: <FORM:0962912/C1/2> where R and R1 are alkylene groups of 2-10 carbon atoms and the other symbols are as above. R and R1 may be branched chain groups such as methyl-substituted ethylene, methyl-substituted trimethylene and ethyl-substituted tetramethylene.  Compounds of the general formula: <FORM:0962912/C1/3> where the organic group \sQQ is a heterocyclic ring which is linked to the group R by its quaternary nitrogen atom, R5 is an aryl group and the other symbols are as above, are prepared by reacting a compound of the formula HO-R(-SR1)d-S-R-OH with a sulphonyl chloride of the formula R5SO2Cl to give a compound of the formula R5SO2-OR(-S-R1)d-S-RO-SO2R5 and then condensing this with the appropriate tertiary heterocyclic amine. This is exemplified by the reaction of 4, 15-dithia-octadecane 1, 18-diol, 7, 13-dithia 1, 19-nonadecane-diol, 7, 18-dithia-tetracosane-1, 24-diol or 7, 10, 13-trithia-nonadecane-1, 19-diol with p-toluene sulphonyl chloride followed by boiling with pyridine or picoline. The pyridinium p-toluene sulphonates so formed may be converted into the corresponding perchlorates by dissolving in water and treating with excess sodium perchlorate.  Compounds of the formula: <FORM:0962912/C1/4> are prepared by quaternizing the corresponding bases.  Thus 1, 18-di-g -pyridyl-4, 15-dithiaoctadecane, 1, 16-bis (1-piperipyl -3, 14-dithia-hexadecane or 1, 16-bis (diethylamino -3, 14-dithia-hexadecane are quaternized by refluxing in ethanol or methanol with methyl p-toluene sulphonate.  1, 18-Di-g -pyridyl-4, 15-dithia-octadecane is prepared by refluxing g -3-mercaptopropyl-pyridine and 1, 10-dibromodecane in methanol. 1, 16-Bis (1-piperidyl)-3, 14-dithia-hexadecane are similarly prepared from b -1-piperidino ethanethiol or b -diethylamino-ethanethiol and 1, 10-dibromodecane.  Specifications 235,211, 541,589, 545,448, 627,814, 636,140, 649,660, 660,012, 680,488, 711,488, 736,922, 739,913, 791,219, 800,108, 873,198, 874,080, 886,722 and 950,089 are referred to.