Patent GB-597329-A (GB)
Title: Improvements in the manufacture of carbocyanine dyes and in photographic emulsions sensitized therewith
IPC: C09B23/06
Filed: 1944-08-11
Abstract: Cyanine dyes are prepared by condensing cyclammonium quaternary salts of the thiazole or selenazole series, having attached to the carbon atom in the a -position to the quaternary nitrogen atom, a b  - cycloalkyl - b  - (alkyl - mercapto)-vinyl group with cyclammonium series having a methyl group attached to the carbon atom in the a -position to the quaternary nitrogen atom.  The condensation may be effected in presence of a basic condensing agent, e.g. trimethylamine, triethylamine, or N-methylpiperidine, and heat may be applied.  9 - Cyclopropyl - 3 : 31 - diethylthiacarbocyanine iodide is prepared by heating together 2-cyclopropylthioformylmethylene - 3 - ethylbenzthiazoline and methyl p-toluenesulphonate and refluxing an absolute ethyl alcohol solution of the product with 2-methylbenzthiazole ethiodide and triethylamine.  9 - Cyclopropyl - 3 : 31 - dimethylthiacarbocyanine bromide, 9-cyclopropyl-3 : 31 - diethyl - 4 : 5 : 41 : 51 - dibenzthiacarbocyanine bromide, 5 : 51 - dichloro - 9 - cyclopropyl-3 : 31 - diethylthiacarbocyanine iodide, p 51 - chloro-9-cyclopropyl-3 : 31-diethyl-4 : 5-benzthiacarbocyanine iodide, 9 - cyclopropyl - 3 : 31 - dimethyl-4 : 5 : 41 : 51 - dibenzthiacarbocyanine iodide, 9 - cyclopropyl - 3 : 31 - diethylselenacarbocyanine iodide, 9 - cyclobutyl - 3 : 31 - diethylthiacarbocyanine iodide, 9 - cyclohexyl - 3 : 31 - diethylthiacarbocyanine iodide, 5 : 51-dichloro-9-cyclohexyl-3 : 31-diethylthiacarbocyanine p-toluenesulphonate, 9 - cyclohexyl - 3 : 31 - diethyl - 4 : 5 : 41 : 51 - dibenzthiacarbocyanine iodide, 9-cyclohexyl-3 : 31-diethylselenacarbocyanine iodide, 5 : 51 - dichloro9-cyclobutyl-3 : 31-diethylthiacarbocyanine iodide, 9-cyclopropyl-3 : 31-diethyl-4 : 5-benzthiacarbocyanine iodide and 5 : 51-dichloro-9-cyclopropyl-3 : 31 - diethylselenathiacarbocyanine iodide are similarly prepared.  2 - Cyclopropylformylmethylene - 3 - ethylbenz - thiazoline is prepared by adding cyclopropane-carboxylic acid chloride slowly to a chilled suspension of 2-methylbenzthiazole etho-p-toluenesulphonate in pyridine. 2-Cyclopropylformylmethylene - 1 - ethyl - b  - naphthathiazoline, 2 - cyclopropylformylmethylene - 3 - ethylbenz - selenazoline, 5-chloro-2-cyclopropylformylmethylene - 3 - ethylbenzthiazoline and 2 - cyclohexylformylmethylene - 3 - ethylbenzthiazoline are similarly prepared.  2-(b -Chloro-b -cyclopropylvinyl)-benzthiazole ethochloride is prepared by adding phosphorus oxychloride to a solution of 2-cyclopropylformylmethylene-3-ethylbenzthiazoline in dry benzene. 2-(b -Chloro-b -cyclopropylvinyl)-b -naphthathiazole ethochloride, 2-(b -chloro-b -cyclopropylvinyl)-benzselenazole ethochloride, 2 - (b - chloro - b  - cyclopropylvinyl) - 5 - chlorobenzthiazole ethochloride and 2-(b -chloro-b -chloro-b -cyclohexylvinyl)-benzthiazole ethochloride are similarly prepared. 2-Cyclopropylthioformylmethylene-3-ethylbenzthiazoline is prepared by refluxing 2-(b -chloro - b -cyclopropylvinyl) - benzthiazole ethochloridewith an ethyl alcohol solution of thioacetamide.  2 - Cyclopropylthioformylmethyl - 3 - methylbenzthiazoline, 2 - cyclopropylthioformylmethylene - 1 - ethyl - b  - naphthathiazoline, 2 - cyclopropylthioformylmethylene - 1 - methyl - b  - naphthathiazoline, 1 - cyclopropylthioformylmethylene - 3 - ethylbenzthiazoline, 5-chloro-2-cyclobutylthioformylmethylene-3-ethylbenzthiazoline, 5-chloro-2-cyclohexylthioformylmethylene - 3 - ethylbenzthiazoline, 2-cyclohexylthioformylmethylene - 1 - ethyl - b  - naphthathiazoline and 2 - cyclohexylthioformylmethylene - 3 - ethylbenzselenazoline are similarly prepared.  Specifications 466,269, 533,425, 538,857 and 585,666 are referred to.