Patent GB-629122-A (GB)
Title: Improvements in the manufacture of intermediates for the production of dyes, in the manufacture of polymethin dyes and in photographic silver salt emulsions containing such dyes
IPC: C09B23/12
Filed: 1946-02-22
Abstract: Polymethine dyes are prepared by condensing a heterocyclic ternary nitrogen base having a dianiloisopropylidene group in the a - or g -position to the ternary nitrogen atom with a quaternary salt of a heterocyclic nitrogen compound having a methyl group in the a - or g -position to the quaternary nitrogen atom by bringing them together, if necessary with heating and if necessary in presence of a condensing agent, the time and temperature of reaction being sufficient to cause one molecular proportion of the base to combine with one molecular proportion but insufficient to combine with two molecular proportions of the quaternary salt and to give a dye of the general formula <FORM:0629122/IV (c)/1> wherein P1(R2) and P2(R3) represent the residues of heterocyclic nitrogen compounds connected in the a - or g - position to the N atoms to which the groups R2 and R3 are attached, R2 and R3 represent alkyl or aralkyl, Ar1 represents a phenyl or substituted phenyl group, and X represents an anion. These dyes may be condensed with a quaternary salt of a heterocyclic nitrogen compound having a methyl group in the a - or g -position to the quaternary N atom by heating together in presence of a condensing agent to give neocyanine-type dyes in which the three nuclei are the same, in which one differs from the other two, or in which all three nuclei are different, or may be condensed with a 5- or 6-membered heterocyclic compound having an intracyclic reactive methylene group adjacent to a carbonyl or thiocarbonyl group.  [4 - (1 - Ethylquinoline)] [2 - (3 - ethylbenzthiazole)] - g  - anilomethyltrimethinecyanine iodide is prepared by heating together 3-ethyl-2 - dianiloisopropylidenebenzthiazoline, lepidine ethiodide, and pyridine.  Similar dyes may be prepared in which both nuclei are 2-(3) ethylbenzthiazole) or in which one is 2-(3-ethylbenzthiazole) and the other 2-(1-ethylquinoline), or 2 - (3 - ethyl - D 2 - thiazoline (both a - and g -anilomethyl dyes), in which one nucleus is 4-(1-ethylquinoline), 2-(1-ethylquinoline), or 2-(3-ethyl-D 2-thiazoline) and the other 2-(4-methyl-3-ethylthiazole); in which one nucleus is 4-(1-ethylquinoline and the other 2-(3-ethyl-D 2-thiazoline, or in which both nuclei are 2-(3-methyl-D 2-thiazoline).  [Bis - 2 - (3 - ethylbenzthiazole)] [a  : b 1 - dimethine - 21 - (31 - ethylbenzselenazole)] - trimethinecyanine di-iodide is prepared by heating together [Bis - 2 - (3 - ethylbenzthiazole)]-a -anilomethyltrimethinecyanine iodide, 2-methylbenzselenazole ethiodide, anhydrous sodium acetate, and acetic anhydride.  Similar dyes may be prepared in which one nucleus is 2-(1 - ethylquinoline), or 4 - (1 - ethylquinoline) and the other two 2-(3-ethylbenzthiazole), in which one is 2-(3-ethylbenzthiazole) or 2-(4-methyl-3-ethylthiazole) and the other two 2-(3-ethyl-D 2-thiazoline), in which one is 2-(1 - ethylquinoline), one 2 - (3 - ethylbenzthiazole), and the third 4-(1-ethylquinoline) or 2-(3-ethylbenzselenazole), or in which one is 4-(1-ethylquinoline), one 2-(3-ethyl-D 2-thiazoline) and the third 2-(3-ethylbenzthiazole. [2 - (4 - Methyl - 3 - ethylthiazole)] [5 - (3-ethylrhodanine)] [a  : b 1 - dimethin - 21 - (31 ethyl - D 2 - thiazolinium iodide)] - dimethinemerocyanine is prepared by heating together [2 - (3 - ethyl - D 2 - thiazoline] [2 - (4 - methyl-3 - ethylthiazole)] - g  - anilomethyltrimethine cyanine iodide, 3-ethylrhodenine, anhydrous sodium acetate, and acetic anhydride.  Specifications 408,272, [Group XX], 408,273, 629,106 and 629,123 are referred to.