Patent GB-665289-A (GB)
Title: Process for the preparation of 2-arylacylamino-2-thioethylidene derivatives of heterocyclic nitrogen bases, for the preparation of quaternary salts of the latter and cyanine dyes and photographic emulsions containing any of these
IPC: C09B23/01
Filed: 1949-01-13
Abstract: Compounds of the general formula <FORM:0665289/IV (b)/1> wherein Z represents the atoms necessary to complete a benzthiazoline, benzselenazoline, a - or b -naphthathiazoline, dihydroquinoline, 4-thiazoline, thiazolidine, or 3 : 3-dimethylindoline nucleus, R is alkyl (or where Z completes a benzthiazoline or thiazolidine nucleus an alkyl or aryl group), R1 is an aliphatic acyl group, R2 is aryl, and n is 0 or 1, are prepared by acylating the compounds wherein R1 is hydrogen with an aliphatic carboxylic anhydride, e.g. acetic, propionic, n-butyric, or iso-butyric anhydride.  2- ( 2- Acetanilido - 2 - thioethylidene)3 ethylbenzthiazoline is prepared by refluxing together 2-(2-anilino-2-thioethylidene)-3-ethylbenzthiazoline, acetic anhydride, and pyridine.  2 - (2 - Acetanilido - 2 - thioethylidene) - 1 - ethyl - b  - naphthathiazoline, 2 - (2 - acetanilido - 2 - thioethylidene) - 3 - methylbenzthiazoline, 2 - (2 - acetanilido - 2 - thioethylidene) - 3 - ethylbenzselenazoline, 2 - (2 - acetanilido - 2 - thioethylidene) - 5 - chloro - 3 - ethylbenzthiazoline, 4 - (2 - acetanilido - 2 - thioethylidene) - 1 - methyl - 1 : 4 - dihydroquinoline, 2 - (2 - acetanilido - 2 - thioethylidene) - 1 : 3 : 3 - trimethylindoline, 2 - (2 - acetanilido - 2 - thioethylidene) - 1 - ethyl - 1 : 2 - dihydroquinoline, 2 - (2 - propionanilido - 2 - thioethylidene) - 3 - ethyl - 4 - methyl - 4 - thiazoline), and 2 - (2 - acetanilido - 2 - thioethylidene) - 3-methylthiazolidine are similarly prepared.  b  - Acylated arylamino - b  - alkylmercaptovinyl cyclammonium quaternary salts of the general formula <FORM:0665289/IV (b)/2> wherein R1 is an aliphatic acyl group, R3 is alkyl and X1 is an anion are prepared by heating N-acyl derivatives of compounds of the first general formula with an alkyl ester R3X1.  In an example, 2-(2-acetanilido-2-thioethylidene)-1 - ethyl - b  - naphthathiazoline and methyl - p - toluenesulphonate are heated together.ALSO:Cyanine dyes are prepared by condensing a compound of the general formula <FORM:0665289/IV (c)/1> wherein Z represents the atoms necessary to complete a benzthiazoline, benzselenazoline, a -or b -naphthathiazoline, dihydroquinoline, D 4-thiazoline, thiazolidine, or 3 : 3-dimethylindoline nucleus, R is alkyl (or where Z completes a benzthiazoline or thiazolidine nucleus, alkyl or aryl), R1 represents an aliphatic acyl group, R2 is aryl, n is 0 or 1, and R3 is alkyl, with a cyclammonium quaternary salt having a reactive methyl group in the 2- or 4-position to the quaternary nitrogen atom, preferably in the presence of a basic condensing agent.  3 : 31-Diethyl - 9 - methylmercapto - 4 : 5 : 41 : 51 - dibenzthiacarbocyanine bromide (Fig. 14) is prepared by heating together 2-(2-acetanilido-2-thioethylidene) - 1 - ethyl - b  - naphthathiazoline and methyl p-toluenesulphonate to obtain a compound of the general formula above, refluxing the product with 2-methyl-b -naphthathiazole etho-p-toluenesulphonate in pyridine, and treating the hot reaction mixture with a hot aqueous solution of potassium bromide.