Patent GB-595784-A (GB)
Title: Improvements in or relating to cyanine dyestuffs
IPC: C09B23/01
Filed: 1945-07-03
Abstract: <FORM:0595784/IV/1> <FORM:0595784/IV/2> <FORM:0595784/IV/3> <FORM:0595784/IV/4> <FORM:0595784/IV/5> A cyanine dye is prepared by reacting in the presence of a base an intermediate of the formula of Fig. 1 (wherein D1 is the residue of a thiazole or selenazole or of a polycyclic homologue thereof or of a thiazoline, selenazoline, diazine, or diazole, D is a chain of three methylene groups, any of which may be hydrocarbon-substituted, R1 is H or a hydrocarbon group, R2 is alkyl or aralkyl, X is an acid radical, and n is 0 or 1) with an intermediate of the formula of Fig. 12 (wherein D2 is a similar residue to D1 or is a residue of pyridine or a polycyclic homologue or of lepidine, R3 is alkyl or aralkyl, R4 is H or hydrocarbon, Y is an acid radical, and n is 0 or 1) or with an intermediate in which the -CH2R4 grouping of Fig. 2 is replaced by an -NHR4 grouping or with an intermediate of the formula of Fig. 3 (wherein D3 is the residue of a 5-membered heterocyclic nitrogen keto-methylene compound and R5 is H or a hydrocarbon group).  The reaction is preferably effected in presence of a solvent for the reactants.  When the intermediate of Fig. 3 has the formula of Fig. 4 (Z being O or S), the resulting product may be treated with an alkyl or aralkyl ester and condensed further with any of the compounds of Fig. 2 or Fig. 3, and this process may be repeated.  The base may be triethylamine or a solution of sodium or sodium acetate in ethyl alcohol.  In examples, dyes are prepared (1) by fusing together D 2 : 3-(3-ethylthio-5 : 5-dimethyl) - cyclohexenone (1), 1 - methylbenz - thiazole and methyl p-toluenesulphonate, adding acetic anhydride and refluxing, adding a pyridine solution of the cooled mass obtained by fusing together lepidine and methyl p-toluenesulphonate, refluxing, adding triethylamine, refluxing further, and pouring into aqueous KI solution; (2) by refluxing together 5 : 5 - dimethyl - 3 - (a  - methenylbenzthiazole methiodide) - cyclohexanone (1), quinaldine methiodide and pyridine, adding triethylamine and further refluxing, and pouring into aqueous KI solution; (3) by fusing together 1-methylbenzselenazole and methyl p-toluenesulphonate, adding 5 : 5-dimethyl-3-(a -methenylbenzthiazole methyl - p - toluenesulphonate) - cyclo hexanone (1) and pyridine and boiling, adding triethylamine and further boiling, and pouring into aqueous KI solution; (4) by heating together 3-(a -methenylbenzthiazole methyl p-toluenesulphonate) - cyclohexanone (1), 1 : 4 - dimethylbenzthiazole ethiodide, and alcohol, adding triethylamine and boiling and pouring into aqueous KI solution; (5) by boiling together 5 : 5-dimethyl-3-(a -methenylbenzthiazole methyl p - toluenesulphonate) - cyclohexanone (1), 1 - phenyl - 3 - methyl - 5 - pyrazolone, and pyridine, adding triethylamine and refluxing, pouring into water and acidifying with glacial acetic acid; and (6) by warming together 5 : 5 - dimethyl - 3 - (a  - methenylbenzthiazole methyl p-toluenesulphonate)-cyclohexanone (1), N-methylrhodanine and ethyl alcohol, and adding triethylamine and boiling.  Specifications 426,718, 595,783 and 595,785 are referred to.