GB929395A - - Google Patents

Abstract

The Specification relates to methine dyes of the general formula:- <FORM:0929395/IV(a)/1> wherein R2 is a carbalkoxy group, R3 is hydrogen or alkyl and R5 is the residue of a 5-pyrazolone, cyanacetic acid or an alkyl ester, substituted alkyl ester or amide thereof, or of malonic acid dinitrile, the residue R5 being free from sulphonic acid groups and all the said alkyl and alkoxy groups containing from 1 to 5 carbon atoms. The dyes are prepared by condensing a compound R5H2 with a 3;3-dimethyl-5-carbalkoxy-2-methylene indoline-o -aldehyde, preferably in an alkaline medium. An emulsifying agent such as polyoxyethylene oleyl ether also may be present. In the case where R5 is the residue of a 5-pyrazolone, the dyes may be prepared by reacting a 3;3-dimethyl-5-carbalkoxy-2-methyleneindoline with a 5-pyrazolone having in its 4-position a -CHO or =CH-N(alkyl)2 group, preferably in the presence of an acid. Pyrazolone components are specified having a 1-phenyl, chlorophenyl, dichlorophenyl, nitrophenyl, aminophenyl, acetylaminophenyl, carboxyphenyl or methyl-phenyl substituent and a 3-methyl or carboxylic acid ester or amide substituent. Specification 929,394 also is referred to.