Patent GB-513471-A (GB)
Title: Improvements in and relating to the production of dyes and their use for sensitizing photographic silver halide emulsions
IPC: G03C1/12
Filed: 1938-03-08
Abstract: 513,471. Sensitizing dyes. DU PONT FILM MANUFACTURING CORPORATION. March 8, 1938, No. 7273. Convention date, March 9, 1937. [Class 2 (iii)] [Also in Group XX] Dyes suitable for sensitizing photographic silver halide emulsions are made by reacting a bisazole dithioether alkly quarternary salt of the formula [Y & Z=O, S or Se, R=aryl, X=an acid radical] with an alkyl quarternary salt of a heterocyclic nitrogen compound containing a reactive alkyl group in (alpha- or gamma-position to the nitrogen atom. Generally only one thioalkyl group reacts but in some cases by-products may be formed due possibly to the reaction of both thioalkyl groups. In the examples (1) the dimercaptobisthiazole from p-phenylenidiamine is treated with dimethyl sulphur, the dithioether obtained converted into a quarternary salt by heating with ethyl p-toluene sulphonate or diethylsulphate &c. The salt condensed in alcohol with 2-methylbenzthiazole ethyl iodide in presence of sodium acetate, (2)-(5) the dithioether ethyl sulphate of (1) is condensed with lepidine ethiodide, #-naphthoquinaldine ethiodide, 2-methylbenzselenazole ethiodide or 2-ethyl-5-methylbenzselenazole ethiodide, (6)-(8), (10)-(13) the 2:2'-dimercaptan of tolylbisthiazole from 1-methyl-2:4-diaminobenzene is methylated as above, converted into the ethyl p-toluenesulphonate or ethyl sulphate and condensed with 2-methylbenzthiazole ethiodide, 2-methylbenzselenazole ethiodide, quinaldine ethiodide, lepidine ethiodide, #-naphthaquinaldine ethiodide, 2-metbyl- #-naphthathiazole ethyl sulphate or 2-methylbenzoxazole ethiodide, (9), (14)-(18) the 2:2<1>-dimethylmercaptobenzbisthiazole from m-phenylene diamine is heated with diethyl sulphate and the quaternary salt condensed with 2:5-dimethylbenzselenazole ethiodide, 2 - methyl - benzthiazole ethiodide, 2-ethyl-5-methylbenzthiazole ethiodide, quinaldine ethiodide, 2- methylbenzoxazole ethiodide or lepidine ethiodide. Other starting materials specied are 6- methyl-, 6-ethoxy- or 7:8-benzlepidine; alkyl, halogen or alkoxy derivatives of 2-methylquinoline ; 2:5-dimethyl-benzthiazole or benzsolenazole, 2-ethyl-5-methyl-benzthiazole or benselenazole and other derivatives containing alkyl, alkoxy, halogen, or dialkylamino ; 2-methylalpha-naphthaselenazole ; 2:4 - dimethyl - thiazole. oxazole or selenazole, 2-methyl-4-phenyl-or 4:5- diphenylthiazole ; 2:3:3-trimethylindolenine. The bisazole dithiother alkyl quaternary salts may be made (1) by heating an aromatic diamine with carbon disulphide and sulphur to give the dimercaptobisthiazole, alkylating, and heating with an alkyl salt, (2) by treating o-o<1> diaminodiselenophenols or o:o<1>-diaminodihydroxybenzenes with thiophosyene to form the corresponding 2:2<1>-dimercapto-benzolisselenazoles or oxazoles which are converted into the thioethers by heating with alkyl sulphates ; thus, 2:5-diaminohydroquinone when heated with thiophosgene gives 2:2<1>-dimercaptobenzobisoxazole. Specifications 424,559, and 464,852 [both in Group XX] are referred to.