Patent GB-713293-A (GB)
Title: Improvements in and relating to methine dyes
IPC: C09B23/00
Filed: 1951-04-09
Abstract: 3 - Methylpyrido - (k,1) - phenothiazinium iodide is prepared by adding concentrated sulphuric acid dropwise with stirring to a suspension of phenothiazine and anhydrous zinc chloride in absolute ethanol and o-nitrophenol, heating to boiling, adding methyl vinyl ketone dropwise, refluxing, and, as a final step after removal of alcohol, excess phenothiazine, &c. adding sodium iodide and chilling.ALSO:A monomethine, carbocyanine, merocarbocyanine, styryl, or pyrrolocarbocyanine dye contains a quinoline nucleus having a bridge of atoms from the 1- to the 8- position completing a 5:6-benz-3-thiazine ring.  Dyes of the general formula: <FORM:0713293/IV(c)/1> (II) wherein n is 1 are prepared by condensing a cyclammonium quaternary salt containing in a - or g - position a thioether group (e.g. alkylthio, aralkylthio, or arylthio) or a halogen atom (e.g. a chlorine, bromine, or iodine atom) with a cyclammonium quaternary salt of the general formula. <FORM:0713293/IV(c)/2> (VII) Dyes of the general formula (II), wherein n is 2, are prepared by condensing a cyclammonium quaternary salt of the general formula (VII) above with a cylammonium quaternary salt containing in the a - or b - position a b -arylaminovinyl or a b -alkyl- or b -aryl-mercaptovinyl group. 3-Ethyloxa-[3\sv-pyrido-(k l)-phenothiazino]-carbocyanine iodide is prepared by refluxing together 3-methylpyrido-(k, l,)-phenothiazinium iodide, 2-b -acetanilidovinylbenzoxazole ethiodide triethylamine, and ethanol. 3-Ethylthia-(3\svpyrido-(k, l)-phenothiazino)-carbocyanine, iodide is similarly prepared.  Dyes of the general formula: <FORM:0713293/IV(c)/3> (III) are prepared by condensing a cyclammonium quaternary salt of the general formula (VII) with a compound of the general formula:  <FORM:0713293/IV(c)/4> (VIII) wherein Q represents the atoms to complete a 5-membered heterocyclic ring.  Dyes of the general formula:  <FORM:0713293/IV(c)/5> (IV) are prepared by condensing a cyclammonium quaternary salt of the general formula (VII) with the appropriate aldehyde. 3-p-Dimethylaminostyrylpyrido-(k, l)-phenothiazinium iodide is prepared by refluxing together 3-methyl - pyrido-(k, l)-phenothiazinium iodide and p-dimethylamionbenzaldehyde in acetic anhydride.  Dyes of the general formula:  <FORM:0713293/IV(c)/6> (V) wherein Q, represents the atoms to complete a heterocyclic nucleus of the pyrrole series and R3 is a substituted or unsubstituted alkyl group (including an aralkyl group) are prepared by condensing a cyclammonium quaternary salt of the general formula (VII) with an aldehyde of the general formula:  <FORM:0713293/IV(c)/7> (X) 2\sv : 5\sv-Dimethyl-l\sv-phenyl-3-pyrido-(k, l)-phenothiazino-pyrrolocarbocyanine iodide is prepared by refluxing together 3-methylpyrido-(k, l)-phenothiazinium iodide, 2 : 5-dimethylpyrrole-3-aldehyde, and acetic anhydride.  Dyes of the general formula:  <FORM:0713293/IV(c)/8> (XV) are prepared either by condensing a cyclammonium quaternary salt of the general formula (VII) with an ortho ester of a carboxylic acid (e.g. ethyl orthoformate) or a dialkoxymethyl carboxylate, or by heating together a cyclammonium quaternary salt of the general formula (VII) and iodoform in the presence of an alcoholic solution of an alkali metal hydroxide. 3-3\sv-Pyrido-(k, l,)-phenothiazinocarbccyanine iodide is prepared by refluxing together 3-methylpyrido-(k, l)-phenothiazinium iodide, diethoxymethyl acetate, and pyridine.