Patent GB-610064-A (GB)
Title: Improvements in methods of making cyanine dyes and in photographic emulsions containing them
IPC: C09B23/04
Filed: 1945-11-17
Abstract: Di-2-benzoxazolylmethane is prepared by refluxing together o-aminophenol and ethyl malonate, a stream of CO2 gas being passed through the apparatus.  Di-2-benzthiazolylmethane and di-2-benzselenazolylmethane are similarly prepared. 2-Benzthiazolyl-2-quinolylmethane is prepared by refluxing together 2-chlorobenzthiazole and quinaldine.  Di - 2 - benzthiazolyl - 2 - quinolyl - methane is obtained as a by-product.  2 - (3 - b  - Bromoethyl - 2 - benzthiazolylidene) - methylbenzthiazole is prepared by heating together 2 - (3 - b  - hydroxyethyl - 2 - benzthiazolylidene)-methylbenzthiazole and phosphorus tribromide. 2-(3-b -Bromoethyl-2-benzthiazolylidene) - methylquinoline and 2 - (3 - g  - bromo - propyl - 2 - benzthiazolylidene) - methylbenzthia - zole are similarly prepared.  2 - (3 - b  - Hydroxyethyl - 2 - benzthiazolylidene)-methylbenzthiazole is prepared by heating together di-2-benzthiazolylmethane and ethylene bromohydrin, and rendering alkaline with ammonium hydroxide.  2 - (3 - g  - Hydroxy - propyl - 2 - benzthiazolylidene) - methylbenzthia - zole is similarly prepared from di - 2 - benz - thiazolylmethane and trimethylenebromo - hydrin.  2 - (3 - b  - Hydroxyethyl - 2 - benzthiazolylidene)-methylquinoline is prepared by refluxing together 2 - methylbenzthiazole b  - hydroxyethobromide and 2-methylmercaptoquinoline, and adding triethylamine.ALSO:A cyanine dye of the general formula <FORM:0610064/IV (c)/1> wherein Z and Z1 each represent the nonmetallic atoms necessary to complete a 5- or 6-membered heterocyclic ring, X represents an anion, and n is 2 or 3 is prepared by heating a di-heterocyclylmethane of the general formula <FORM:0610064/IV (c)/2> with an ethylene or propylene arylsulphonate, and then treating the product with an acid-binding agent.  The dye may also be prepared by heating an N-bromoethyl or N-bromopropyl cyanine base of the general formula <FORM:0610064/IV (c)/3> The heating may be effected at from 150 DEG  to 200 DEG  C., and the acid-binding agent may be a trialkylamine, a dialkylamine, an N-alkylpiperidine, sodium carbonate or ammonia.  The dye arylsulphonates obtained in the first method may be converted to iodides, bromides, or perchlorates, and the dye bromides obtained in the second process may be converted to iodides or perchlorates. The bromides or iodides may be converted into chlorides by treatment with silver chloride in a phenol.  3 : 31-Ethylenethiacyanine iodide is prepared by heating together di-2-benzthiazolylmethane and ethylene di-p-toluenesulphonate, suspending the product in hot methyl alcohol and adding triethylamine, and adding a hot methyl alcohol solution of sodium iodide.  1 : 11-Ethylene-2 : 11-cyanine iodide, and 3 : 31-ethyleneoxacyanine iodide are similarly prepared, and dyes can be obtained similarly from di-2-benzselenazolylmethane, di-2-(4-thiazolyl)-methane, di-2-(4-phenylthiazolyl) - methane, di - 2 - (5 - methyl - benzoxazole) - methane, 2 - benzthiazolyl - 2 - quinolylmethane and 2 - benzoxazolyl - 2 - benzthiazolylmethane.  3 : 31-Propylenethiacyanine bromide is prepared by heating 2-(3-bromopropyl-2-benzthiazolylidene)-methylbenzthiazole.  3 : 31-Ethylenethiacyanine iodide and 11 : 3-ethylenethia-21-cyanine iodide are similarly prepared.