GB696646A - Improvements in methine cyanine dyes - Google Patents

Abstract

Pyrrole derivatives of the general formula <FORM:0696646/IV (b)/1> wherein R1 and R2 are aryl, and R3 is alkyl, aralkyl or cycloalkyl are prepared by reacting the sodium or potassium salts of the corresponging pyrrole bases with R-X, where X is a halogen atom. 1 - n - Butyl - 2 : 4 - diphenylpyrrole is prepared by heating 2 : 4-diphenylpyrrole with dry dioxane, discontinuing heating and adding potassium, heating, adding n-butyl iodide, and filtering off the potassium iodide. 1-Methyl-2 : 4 - diphenylpyrrole, 1 - ethyl - 2 : 4 - diphenylpyrrole, 1 - n - propyl - 2 : 4 - diphenylpyrrole, and 1-higher alkyl-2 : 4-diphenylpyrroles are similarly prepared. 1 - Methyl - 2 : 4 - diphenylpyrrole, 1 - n-butyl - 2 : 4 - diphenylpyrrole, 1 - ethyl - 2 : 4-diphenylpyrrole, and 1 - n - propyl - 2 : 4-diphenylpyrrole are sulphonated by heating with 20 per cent oleum. Specification 533,238 is referred to.ALSO:Dyes of the general formula <FORM:0696646/IV (c)/1> wherein R1 and R2 are aryl, R3 is alkyl, aralkyl or cycloalkyl, L is substituted or unsubstituted methine, X is an anion, and n is 1, 2 or 3, are prepared by condensing compounds of the general formula <FORM:0696646/IV (c)/2> with formic acid, formaldehyde, a diarylformamidine, a trialkyl orthocarboxylate, benzotrichloride, a halide of a monocarboxylic acid, b -alkoxyacrolein dialkylacetal, an alkali metal glutaconic dialdehyde, or a monoacyl glutaconic dialdehyde. Bis - 2 - (1 - methyl - 3 : 5 - diphenylpyrrole) - trimethinecyanine perchlorate is prepared by heating together 1-methyl 2 : 4-diphenylpyrrole, ethanol, b -ethoxyacraldehyde diethylacetal (or propargyl aldehyde), and perchloric acid. Bis - 2 - (1 - dodecyl - 3 : 5 - diphenylpyrrole) - trimethinecyanine perchlorate, sulphonated bis-2-(1-methyl - 3 : 5 - diphenylpyrrole) - trimethinecyanine perchlorate, sulphonate bis-(1-n-butyl-3 : 5 - diphenylpyrrole) - trimethinecyanine perchlorate, sulphonated bis - 2 - (1 - n - butyl - 3 : 5 - diphenylpyrrole) - a - phenyltrimethinecyanine perchlorate (using phenylpropargyl aldehyde diethyl acetal), sulphonated bis-2-(1-ethyl-3 : 5-diphenylpyrrole) - trimethinecyanine perchlorate, sulphonated bis - 2 - (1 - n - propyl - 3 : 5 - diphenylpyrrole) - trimethinecyanine perchlorate, and bis - 2 - (1 - methyl - 3 : 5 - diphenylpyrrole) - a -phenyltrimethinecyanine perchlorate are similarly prepared. Bis - 2 - (1 - methyl - 3 : 5 - diphenylpyrrole) - monomethinecyanine perchlorate is prepared by heating together 1 - methyl - 2 : 4 - diphenylpyrrole and formic acid, cooling, and adding perchloric acid. Bis - 2 - (1 - methyl - 3 : 5 - diphenylpyrrole) - pentamethinecyanine sulphate is prepared by adding sulphuric acid and then sodium glutaconic dialdehyde to a methanol solution of 1 - methyl - 2 : 4 - diphenylpyrrole. Bis - 2 - (1 - cyclohexyl - 3 : 5 - diphenylpyrrole) - pentamethinecyanine sulphate, and bis-2-(1-butyl-3 : 5-diphenylpyrrole) - pentamethinecyanine perchlorate trisulphonic acid are similarly prepared. Specification 533,238 is referred to.