Patent GB-675227-A (GB)
Title: Improvements in or relating to cyanine dyes
Inventor: KENDALL JOHN DAVID
IPC: C09B23/01
Filed: 1949-10-20
Abstract: Cyanine dyes of the general formula <FORM:0675227/IV (c)/1> wherein R1 and R3 are alkyl, aralkyl, or aryl, R2 is alkyl or aralkyl, D1 and D2 are the residues of 5- or 6-membered heterocyclic nuclei, m and n are 0 or 1, x is 0 or 1, and X is an acid radical, are prepared by reacting a compound of the general formula <FORM:0675227/IV (c)/2> produced by the process of Specification 675,226, [Group IV (b)], with a compound of the general formula <FORM:0675227/IV (c)/3> wherein Y is an acid radical and Q is an alkyl-, aralkyl-, or aryl-thioether group or an amino or substituted amino (preferably acetamino or acetanilido) group.  The reaction may be effected in the presence of a basic condensing agent, and the process may be modified by condensing a 2-acylmethylene heterocyclic base simultaneously with an alkyl-p-toluenesulphonate and a compound of the third general formula, which itself may be formed in situ by condensing the corresponding thione or thioether base with the alkyl-p-toluenesulphonate.  Where Q is a thioether group and x is 1, the corresponding methyl derivative of the heterocyclic compound may be reacted with a trialkyl trithio-orthoformate in the presence of acetic anhydride, and the intermediate so obtained used without purification in the production of the dye.  3 : 31 - Dimethyl - 11 - methoxyoxathiadicarbocyanine iodide is prepared by refluxing together 2 - b  - methyl : b  - methoxyvinylbenzthiazole metho - p - toluenesulphonate, 2 - ethylthiovinylbenzoxazole metho - p - toluenesulphonate, ethanol, and triethylamine, and pouring into potassium iodide solution.  3 : 31-Dimethyl-9-methoxythiadicarbocyanine bromide and 1 : 31-dimethyl - 11 - methoxyindothiadicarbocyanine iodide are similarly prepared.  3 - Methyl - 31 - ethyl - 9 - methoxythiacarbocyanine iodide is prepared by fusing together 2-acetylmethylene - 3 - methyl - 2 : 3 - dihydrobenzthiazone and methyl p-toluenesulphonate, adding 2 - methylthiobenzthiazole ethiodide, ethanol, and triethylamine, and refluxing.  3 - Methyl - 31 - ethyl - 9 - ethoxythiacarbocyanine iodide, 3 : 31 - dimethyl - 9 - methoxythiacarbocyanine iodide, 3 : 31-dimethyl-9-ethoxythiacarbocyanine iodide, 3 : 31 - diethyl - 9 - ethoxythiacarbocyanine iodide, 3 : 31 - diethyl - 9 - methoxythiacarbocyanine iodide, 3 - ethyl - 31 - methyl - 9 - n-propoxythiacarbocyanine iodide, 3 : 31-dimethyl - 9 - n - propoxythiacarbocyanine iodide, 3 - methyl - 31 - ethyl - 9 - methoxy - 61 : 71 - benzthiacarbocyanine iodide, 3 : 11-dimethyl-9-methoxythiaquinocarbocyanine iodide, 1 : 31-dimethyl-9-methoxyindothiacarbocyanine perchlorate, 1 : 31-dimethyl - 9 - methoxyindoxacarbocyanine perchlorate, 3 - ethyl - 31 - methyl - 9 - methoxythiadicarbocyanine iodide, 1 - ethyl - 31 - methyl - 9 - methoxyindothiadicarbocyanine iodide, 1 : 31 - dimethyl - 11 - methoxyindothiadicarbocyaniniodide, 3 : 31 - diethyl - 9 - ethoxythiadicarbocyanine iodide, 3 : 31 - diethyl - 9 - methoxythiacarbocyanine iodide, 1 : 31 - dimethyl - 9 - methoxyindothiacarbocyanine perchlorate, 1 : 31 - dimethyl - 9 - methoxyindoxacarbocyanine perchlorate, and 3 : 31 - diethyl - 9 - b - phenylethoxythiacarbocyanine iodide are similarly prepared. According to the Provisional Specification, x may be 2. Specification 633,824 also is referred to.