Patent GB-551331-A (GB)
Title: Improvements in and relating to cyclammonium quaternary salts and methine and polymethine dyes derived therefrom and to photographic silver halide emulsions containing such dyes
Filed: 1941-08-16
Abstract: 551,331. Cyclammonium quaternary compounds, methine dyes, photographic sensitized material. KODAK, Ltd. Aug. 16, 1941, No. 10453. Convention date, Aug. 21, 1940. Sample furnished. [Class 2 (iii)] [Also in Group XX] A cyclammonium quaternary salt is prepared by oxidizing, with an oxidizing agent which gives rise to an acid radical, an N-alkyl : N- arylthioamide, an N : N-diarylthioamide, an N-alkyl : N-arylselenoamide, or an N : N-diarylselenoamide. The oxidizing agent may be a halogen, e.g. bromine or iodine. The compound oxidized may be an N-alkyl : N-phenylthioamide or an N : N-diphenylthioamide, and may be a thioacetamide. In an example, 2-methyl-3-phenylbenzthiazolium iodide is prepared by refluxing together thioacetyldiphenylamine, iodine, sodium acetate, and acetic acid to give 2-methylbenzthiazole phenyl triiodide, which is suspended in ethyl alcohol and reduced to the mono-iodide. In a second example, 2-methyl-3 : 4-trimethylenebenzthiazolium iodide is prepared by refluxing together 1-thioacetyl-1 : 2 : 3 : 4-tetrahydroquinoline, iodine, sodium acetate, sodium iodide, and acetic acid. The triiodide obtained is reduced as above. N-methyl : N-phenylthioacetamide; N-methyl : N-α- or #-naphthylthioacetamide, and N-diphenylselenoacetamide can be similarly oxidized to the corresponding cyclammonium quaternary salts. The iodides may be converted into the perchlorates by treatment of the alcoholic solution with an aqueous solution of sodium perchlorate. Carbocyanine dyes are prepared by condensing a quaternary salt of the formula shown in Fig. 3 (where R represents alkyl and X an acid radical), with an ester of an orthocarboxylic acid, e.g. an orthoformic ester. In an example, 3 : 4 : 3<SP>1</SP> : 41-di-(trimethylene)-thiacarbocyanine iodide is prepared by refluxing together 2-methyl-3 : 4-trimethylenebenzthia-. zolium iodide, ethyl orthoformate, and pyridine. The . corresponding 9-methyl- and 9-ethylcompounds are prepared using ethyl orthoacetate and ethyl orthopropionate respectively. Carbocyanine dyes are also prepared by condensing a quaternary salt of the formula shown in Fig. 3, in the presence of an acid binding agent, with a cyclammonium quaternary salt having an acylated #-arylaminovinyl 1 group in the α- or y-position to the quaternary nitrogen atom. In an example, 3-ethyl-3<SP>1</SP> : 4<SP>1</SP>- trimethyleneoxathiacarbocyanine iodide is prepared by refluxing together 2-methyl-3 : 4- trimethylene-benzthiazolium triiodide, 2-(#- acetanilidovinyl)-benzoxazole ethiodide, and pyridine. The dye-triiodide may be reduced to the monoiodide by dissolving in hot methyl alcohol and reducing with sulphur dioxide. 2 - Methyl - 3 : 4 - trimethylenebenzthiazolium iodide can be similarly condensed with 2-(#- acetanilidovinyl) - benzthiazole ethiodide, 2 - (# - acetanilidovinyl) - thiazoline methiodide, or 4-(#-acetanilidovinyl)-quinoline ethiodide. Other acid binding agents are triethylamine, piperidine, N-methylpiperidine, and triethanolamine. Cyanine dyes are prepared by condensing a quaternary salt of the formula shown in Fig. 3 with a cyclammonium quaternary salt having an alkylmercapto or arylmercapto group in the α- or y-position to the quaternary nitrogen atom, in the presence of an acid binding agent. In an example, 1<SP>1</SP>-ethyl-3 : 4-trimethylenethia- 2<SP>1</SP>-cyanine iodide is prepared by refluxing together 2 - methyl - 3 : 4 - trimethylenebenz - thiazolium triiodide, 2-phenylmercaptoquinoline ethiodide, and pyridine. 2-Methyl-3 : 4-trimethylenebenzthiazolium quaternary salts can be similarly condensed with 2-methylmercaptobenzthiazole ethiodide or with 2-phenylmercaptobenzthiazole ethiodide. Methine dyes are prepared by condensing a quaternary salt of the formula shown in Fig. 3 with heterocyclic compounds having an acylated arylaminomethylene group adjacent to a carbonyl group, in the presence of an acid binding agent. In an example, 3-ethyl-5-[(3 : 4- trimethylene - 2 - - benzthiazolylidene) - ethylidene]- rhodanine is prepared by refluxing together 5 - acetanilidomethylene - 3 - ethylrhodanine, 2 - methyl - 3 : 4 - trimethylenebenzthiazolium iodide, and triethylamine in ethyl alcohol. 3 - - Ethyl - 5 - [(3 : 4 - - trimethylene - 2 - - benzthiazolylidene) - ethylidene] - 2 - thio - 2 : 4 - oxazoledione is similarly prepared. Methine dyes may also be prepared by condensing, in the presence of an acid binding agent a quaternary salt of the formula shown in Fig. 3 with heterocyclic compounds having an acylated arylaminoallylidene group adjacent to a carbonyl group. In an example, 3-ethyl- 5 - [(3 : 4 - - trimethylene 2 - benzthiazolylidene) - - butenylidene]-rhodanine is prepared by refluxing together 5 - (y - acetanilidoallylidene) - 3 - ethylrhodanine, 2 - methyl - 3 : 4 - trimethylenebenzthiazolium iodide, and triethylamine in ethyl alcohol. Methine dyes of the styryl type may be prepared by condensing a quaternary salt of the formula shown in Fig. 3 with a dialkylaminobenzaldehyde. In an example, 2-(p-dimethylaminostyryl ) - 3 4 - trimethylene - benzthiazolium iodide is prepared by refluxing together 2- methyl - 3 : 4 - trimethylenebenzthiazolium iodide, p - dimethylaminobenzaldehyde, and piperidine in ethyl alcohol. P-diethylaminobenzaldehyde may also be condensed with the quaternary salts. The dyes may be used as sensitizers for photographic silver halide emulsions, and may be incorporated in the washed finished emulsion or by bathing the finished plate or film. A sample has been furnished under Sect. 2 (5) of the Acts of 2-methyl-3 : 4-trimethylenebenzthiazolium perchlorate, prepared by oxidizing 1-thioacetyl-1 : 2 : 3 : 4-tetrahydroquinoline in presence of fused sodium acetate and acetic acid by addition of bromine in acetic acid, followed by conversion to the perchlorate. The Specification as open to inspection under Sect. 91 refers also to methine dyes obtained from a quaternary salt of the formula shown in Fig. 3 (Cancelled), wherein Q represents selenium, R an alkyl group, X an acid radical, and Z the non-metallic atoms necessary to complete an aryl nucleus. This subject-matter does not appear in the Specification as accepted.