GB895930A - Improvements in dye-sensitized photographic emulsions - Google Patents

Abstract

Complex cyanine dyes are described having the general formula <FORM:0895930/IV (c)/1> wherein R and R1 are alkyl, aralkyl, allyl or substituted alkyl groups or, if Z or Z1 comprises a fused-on benzene ring, they may be alkylene groups joined in peri-position to such benzene ring, R2 is hydrogen or an alkyl or aryl group, Q is =N-(when d is 1) or a =CH- or =CH-(COR3)=CH- group (R3 is alkyl), X is anion, n, m and d are 0 or 1, D and D1 together complete the residue of a 4-thiazolidone, 5-thiazolidone or 4-imidazolidone nucleus, and Z and Z1 complete 5- or 6-membered heterocyclic nuclei. Examples are given of the preparation of dyes wherein Q is =CH- by quaternization of 3 - b - methoxyethyl - 5 - [(1 - methyl - 2 - naphtho [1, 2] thiazolylidene) - a - phenylethyl - idene] rhodanine, 3 - ethyl - 5 - [(3 - ethyl - 2 - 6, 7, 8, 9 - tetrahydronaphtho [2, 1] thiazolyl - idene) - 1 - phenylethylidene] rhodanine, 3 - ethyl - 5 - [(3 - benzyl - 2 - benzothiazolylidene) - ethylidene] rhodanine and 3-ethyl-5-[(5-chloro-1,3-diethyl-2-benzimidazolylidene] rhodanine with methyl p-toluene sulphonate followed by condensing the quaternary salts with 3-ethyl-2-methyl - benzthiazolium iodide, 1 - ethyl - 2 - methylnaphtho [1, 2] - thiazolium p - toluene sulphonate, 2 - methyl - 3, 4 - trimethylene - benzthiazolium iodide and 5-chloro-3-ethyl-2-methyl-benzthiazolium iodide, respectively. A dye wherein Q is =N- is obtained by refluxing 2 - [(2 - b - naphthothiazolyl ethiodide) imino]-3 - phenyl - 4 - thiazolidone with 2 - b - acet - anilidovinyl - 3 - ethylbenzoxazolium iodide in ethyl alcohol in the presence of triethylamine. An example also is given of the preparation of a dye where in Qis =CH-C(OC2H5)=CH- by condensing the quaternary salt obtained by fusing 3-ethyl-5-[(3-ethyl-2-benzoxazolylidene) ethylidene] -rhodanine and methyl p-toluene sulphonate with 2 - (2 - ethoxypropenyl) - 3 - ethylbenzothiazolium iodide in ethyl alcohol in the presence of triethylamine. Specifications 489,335, 524,154, 524,554, 524,555, 541,589, 581,772, 595,065, 623,849, 624,051, 624,052, 646,896, 678,291, 681,642, 705,406, 852,067, 852,069 and 861,194 and U.S.A. Specifications 2,171,427, 2,430,295, 2,440,119, 2,442,710, 2,454,629, 2,473,475, 2,535,982, 2,535,993, 2,563,493, 2,565,351, 2,573,652, 2,580,234, 2,595,030, 2,660,578, 2,71,057 and 2,733,165 are referred to.