GB954240A - Process for the manufacture of basic polymethine dyestuffs - Google Patents

Abstract

Dye intermediates are prepared by reacting one molecular proportion of a compound of the formula: <FORM:0954240/C2/1> wherein R1 and R2 are alkyl, cycloalkyl, aralkyl or aryl groups or together complete a saturated heterocyclic ring, R3 and R4 are hydrogen or alkyl, cycloalkyl, aralkyl or aryl groups and n is 1 or 2, with one molecular proportion of a heterocyclic nitrogen base having an a -or g =-CH2 group. Examples are given of the reaction of dimethyl-formamide chloride with N-methyl-2-methylidene-benzthiazoline or with 1-ethyl-4-methylidene-1; 4-dihydro-quinoline, and of the reaction of dimethyl-acetamide chloride with N-ethyl-2-methylidene-benzthiazoline. The amino-chloride intermediates may be prepared as described in Specifiction 870,454, and such compounds are specified wherein R1 and R2 are methyl or ethyl groups or together complete a piperidine or morpholine ring, or R1 is methyl and R2 is phenyl, R4 is H, methyl or phenyl, and R3 is methyl.ALSO:Cyanine dyes are prepared by reacting one molecular proportion of a compound of the formula <FORM:0954240/C3/1> wherein R1 and R2 are alkyl, cycloalkyl, aralkyl or aryl groups or together complete a saturated heterocyclic ring, R3 and R4 are hydrogen or alkyl, cycloalkyl, aralkyl or aryl groups and n is 1 or 2, with two molecular proportions of a heterocyclic nitrogen base having an a - or g - =CH2 group. The amino-chloride may first be condensed with one molecular proportion of the heterocyclic base to give a dye intermediate of the formula <FORM:0954240/C3/2> wherein Z completes a heterocyclic nucleus, and this may then be condensed with one molecular proportion of a different methylene heterocyclic base to give an unsymmetrical cyanine dye. Examples are given of the reaction of 1 mol. of dimethyl-formamide chloride with 2 mols. of N-methyl-2-methylidene-benzthiazoline or 1;3;3 - trimethyl - 2 - methylidene-indoline to give carbocyanine dyes, or with 1 mol. of the former base to give a dye intermediate. In further examples, 1 mol. of the dichloride obtained from a -methyl-b -dimethylamino-acrolein is reacted with 2 mols. of N-methyl - 2 - methylidene - benzthiazoline to give a meso-substituted dicarbocyanine dye, and unsymmetrical dyes are prepared by reacting dimethyl-formamide chloride with 1-ethyl-4-methylidene-1:4-dihydroquinoline and then with N-ethyl-2-methylidene-benzthiazoline, or by reacting N-ethyl-2-methylidene-benzoxazoline with dimethyl-acetamide chloride and then with N-ethyl-2-methylidene-benzthiazoline. Reference also is made to the preparation of styryl dyes by reacting 1 mol. of the amino-chloride with 1 mol. of the methylene heterocyclic base and 1 mol. of an aromatic amine such as dimethylaniline. Amino-chlorides also are specified where R1 and R2 are ethyl groups or together complete a piperidine or morpholine ring, or R1 is methyl and R2 is phenyl, and where R4 is methyl or phenyl. Specification 870,454 is referred to.