Patent GB-625347-A (GB)
Title: Methin dyes containing an isoquinoline nucleus and photographic emulsions containing them
IPC: C09B23/10
Filed: 1947-05-21
Abstract: Methine dyes of the formula <FORM:0625347/IV (c)/1> wherein R and R1 are each alkyl or substituted alkyl groups, X is an anion, and n is 1 or 2 are prepared either by heating a 3-methylisoquinoline alkyl quaternary salt with a p-dialkylaminobenzaldehyde or p-dialkylaminocinnamaldehyde in the presence of a secondary amine having an ionization constant greater than 10-5 at 25 DEG  C. (e.g. piperidine or 2-methyl-piperidine) and in solution or suspension in pyridine, quinoline, isoquinoline, or an alcohol, or by adding the amine to a fused melt of the reactants.  3 - p - Dimethylaminostyrylisoquinoline ethiodide is prepared by heating together 3-methylisoquinoline and diethyl sulphate, dissolving in hot pyridine, adding p-dimethylaminobenzaldehyde and piperidine and refluxing, and adding hot aqueous KI, or by fusing together 3-methylisoquinoline ethiodide and p-dimethylaminobenzaldehyde and adding piperidine with continued heating.  3 - p - Dimethylaminostyrylisoquinoline n-propiodide, n-butiodide and methoperchlorate, 3 - p - diethylaminostyrylisoquinoline methoperchlorate and 3 - p - di - n - propylaminostyrylisoquinoline ethiodide (first method) and 3-p-dimethylaminostyrylisoquinoline methiodide (second method) are similarly prepared.  3 - [4 - (p - Dimethylaminophenyl) - 1 : 3 - butadienyl]-isoquinoline ethoperchlorate is prepared by refluxing together 3-methylisoquinoline ethiodide, p - dimethylaminocinnamaldehyde, piperidine and ethyl alcohol, and adding hot aqueous NaClO4 to a hot methyl alcohol solution of the product. 3-[4-(p-Diethylaminophenyl)-1 : 3 - butadienyl] - isoquinoline methiodide and methoperchlorate and 3 - [4 - (p - dimethylamino - phenyl) - 1 : 3 - butadienyl] - isoquinoline n-propiodide, n-propoperchlorate, n-butiodide and n-butoperchlorate are similarly prepared.  Carbocyanine dyes of the general formula <FORM:0625347/IV (c)/2> wherein R and X are as above are prepared by heating together a 3-methylisoquinoline alkyl quaternary salt and a trialkyl orthoformate in the presence of isoquinoline.  Triethyl, tri-n-propyl, or tri-n-butyl orthoformate may be used.  2 : 21 - Diethyl - 3 : 31 - isoquinocarbocyanine iodide is prepared by refluxing together 3-methylisoquinoline ethiodide, ethyl orthoformate, triethylamine and isoquinoline.  2 : 21-Dimethyl-, 2 : 21-di-b -hydroxyethyl-, 2 : 21-di-b -ethoxyethyl- and 2 : 21-di-n-butyl-3 : 31-isoquinocarbocyanine iodide are similarly prepared.  Dyes of the general formula <FORM:0625347/IV (c)/3> wherein R and X are as above, R2 and R3 are each alkyl, and R4 is alkyl, aralkyl, or aryl are prepared by heating together a 3-methylisoquinoline quaternary salt and a pyrrole aldehyde of formula  <FORM:0625347/IV (c)/4> 2 : 21 : 41 - Trimethyl - 11 - phenyl - 3 - isoquino - 31 - pyrrolocarbocyanine perchlorate is prepared by reacting together 3-methylisoquinoline and dimethyl sulphate and then heating, adding pyridine and 2 : 5-dimethyl-1-phenyl-3-pyrrolecarboxyaldehyde and then piperidine, refluxing and treating with hot aqueous NaClO4. 11-lauryl - 2 : 21 - 51 - trimethyl-, 11 : 2 - diethyl-21 : 51-dimethyl-, 2 - b  - hydroxyethyl-11-lauryl-21 : 51 - dimethyl and 2 - b  - ethoxyethyl - 11-ethyl-21 : 51 - dimethyl - 3 - isoquino - 31 - pyrrolocarbocyanine perchlorate are similarly prepared.  Specifications 529,440 and 533,238 are referred to.