Methine dyestuffs

摘要

The invention comprises methine dyestuffs of the Formula I where R1 and R2 are each alkyl, aralkyl or cycloalkyl, R is hydrogen, alkyl, aralkyl or aryl, R3 is hydrogen, cyano, carboxylic acid amide, carboxylic acid alkylamide or carboxylic acid ester, R4 is aralkyl, aroxyalkyl or aralkenyl, ring A and the radicals R-R4 may be further substituted and the dyes are free from sulphonic acid groups and also mixtures of at least one dyestuff of the above formula with at least one methine dye of the Formula II where R, R1, R2 and R3 are as above, R5 is cyano or an optionally substituted carboxylic acid amide or ester group and the ring A and R, R1, R2, R3 and R5 may carry further substituents other than sulphonic acid groups. The dyestuffs of Formula I are made by condensing an appropriately substituted 2-methylene-indoline-o -aldehyde, having radicals R1 and R2 in 3-position and R3 on the carbon of the methylene group, with cyanoacetic acid aralkyl, aroxyalkyl or aralkenyl esters, preferably in alkaline medium. The dyestuff mixtures may be made by condensing the same aldehydes with a mixture of the cyanoacetic acid esters above and a different cyanoacetic acid ester, malonodinitrile or a cyanoacetic acid amide. Mixtures of at least two different dyes of Formula I and of at least one dye of Formula I with at least one other methine dye are mentioned. Many examples are given. The dyes and dye mixtures dye and mass-dye synthetic fibres of aromatic polyesters and superpolyamides.