CH618727A5 - Process for the preparation of new cationic dyes and product - Google Patents

Abstract

For the preparation of cationic dyes of formula (I) <IMAGE> with R1 to R5, X and A as in claim 1, the starting material is a compound of formula (II) <IMAGE> which is treated with an alkylating agent. The dyes thus obtained exhibit a good affinity for synthetic fibres of acidic nature and yield pure and bright shades endowed with excellent fastness properties on these fibres.

Description

The present invention relates to a process for the preparation of cationic dyes of formula (I)

45

(IV)

= N "

R

R.

(I).

in which X represents a hydrogen or halogen atom or a methoxy group, Rj and R2 represent the same alkyl group, R3 represents a hydrogen or halogen atom or a nitro group, R4 represents a hydrogen atom or an alkyl, cyanalkyl or hydroxyalkyl group, R5 represents a hydrogen atom or an alkyl or aryl group, and A © represents a monovalent anion.

The process according to the invention for the preparation of the dyes of formula (I) is defined in claim 1.

The invention also relates to the dyes produced according to the inventive method.

In the formulas (III) and (IV), the symbols X, R3, R4 and R5 have the same meanings as below.

The diazotation of the aminopyrazoles of formula (III) is preferably carried out in the presence of an organic acid of low molecular weight, such as acetic or propionic acids, or in the presence of concentrated mineral acid.

The dyes of formula (I) have an excellent affinity for synthetic fibers of acidic nature on which they provide pure and lively shades endowed with excellent properties. By synthetic fibers of acidic nature is meant those based on polymers and copolymers of acrylic nitrile and those based on polyesters or polyamides modified by acid groups. Thanks to the low solubility in water of the 60 dyes according to the invention, in particular those in the form of chlorides, sulfomethylates or chlorozincates, the latter are particularly well suited to the production of dyes according to techniques using cationic dyes in dispersed form.

fis The coloring is imparted by the coloring cation; the anion A © does not modify the shade. It can be exchanged for another anion, for example in order to modify the solubility of the dyes.

618,727

In the examples below, the parts indicated are by weight unless otherwise indicated.

Example 1

4.6 parts of phenyl-3 (5) aniino-5 (3) pyrazole are dissolved in 33 parts of concentrated sulfuric acid. To this solution, cooled to 0 to 5 ° C., a solution of 2.2 parts of sodium nitrite in 27 parts of concentrated sulfuric acid is added and the mixture is left stirring for half an hour. The sulfuric solution of the diazo derivative thus obtained is then gradually added to a solution of 2.3 parts of 1-methyl-2-phenyl indole in 20 parts by volume of dimethylformamide. The mixture is stirred for one hour, then the precipitation of the monoazo compound is completed by progressive addition of water. The precipitate obtained is then filtered, washed with water and dried.

4 parts of (1-methylphenyl-2 indolyl-3 azo) -5 (3) phenyl-3 (5) pyrazole thus obtained are introduced into 20 parts by volume of dimethylformamide. The mixture is heated to 100 ° C., then 5 parts of methyl sulfate are added dropwise. The mixture is kept at 100 ° C. until complete quaternization, a reaction which can be followed by thin layer chromatography. By cooling, the sulfomethylate of 1,2-dimethylphenyl-3 (1-methylphenyl-2 indolyl-3 azo) -5 pyrazolium precipitates. It is filtered and dried under vacuum. It dyes the fibers based on polymers or copolymers of acrylic nitrile in a bright yellow shade, remarkably solid in light.

Table B

This dye can also be isolated in the form of chloro-zincate by dissolving the precipitate obtained above in hot water and reprecipitation by adding a solution of sodium chloride and zinc chloride.

5 The following table A summarizes other examples of dyes according to the invention, obtained as in the previous example from phenyl-3 (5) amino-5 (3) pyrazole, but replacing 1-methylphenyl- 2 indole by an equimolar amount of the coupler indicated in the second column.

10 Table A Ex. Copulant of formula (IV)

2

15 3 4

2-methyl indole 2-phenyl indole 1-ethyl 2-methyl indole p-cyanethyl-1 2-phenyl indole

(2-hydroxypropyl) -1 phenyl-2 indole

Grade on acrylic fibers greenish yellow golden yellow yellow yellow yellow

Table B below summarizes other examples of dyes according to the invention, obtained as in Example 1, but replacing the phenyl-3 (5) amino-5 (3) pyrazole by an equimolar amount of aminopyrazole indicated in the second column and / or methyl-1 phenyl-2 indole by an equimolar amount of the coupler indicated in the third column.

Ex.

Aminopyrazole

Copulant

Nuance on

of formula (III)

of formula (IV)

fibers

acrylic

7

phenyl-3 (5) chloro-4

indole yellow

amino-5 (3) pyrazole

8

do.

2-methyl indole yellow

9

do.

phenyl-2 indole golden yellow

10

do.

1-methyl-2-phenyl

Yellow gold

indole

11

do.

1-ethyl-2-methyl indole yellow

12

do.

ß-cyanöthyl-l methyl-2

yellow

indole

13

do.

P-cyanethyl-l phenyl-2

Yellow gold

indole

14

do.

isopropyl-2 indole yellow

15

phenyl-3 (5) nitro-4

2-methyl indole golden yellow

amino-5 (3) pyrazole

16

do.

phenyl-2 indole orange

17

do.

1-methyl-2-phenyl

orange

indole

18

do.

1-ethyl-2-methyl indole golden yellow

19

do.

P-cyanethyl-1 methyl-2

Yellow gold

indole

20

do.

P-cyanethyl-l phenyl-2

orange

indole

21

do.

(2-hydroxypropyl) -l golden yellow

2-phenyl indole

22

phenyl-3 (5) chloro-4

(2-hydroxypropyl) -l golden yellow

amino-5 (3) pyrazole 2-phenyl indole

23

p-chlorophenyl-3 (5)

methyl-1 phenyl-2

Yellow gold

amino-5 (3) pyrazole indole

24

p-methoxyphenyl-3 (5)

do.

Yellow gold

amino-5 (3) pyrazole

25

p-methoxyphenyl-3 (5)

do.

Yellow gold

VS

Claims (2)

618,727 2 CLAIMS 1. Process for the preparation of cationic dyes of formula (I) = N- R // ^ N 5 A m. A © in which X represents a hydrogen or halogen atom or a methoxy group, and R2 represent the same alkyl group, R3 represents a hydrogen or halogen atom or a nitro group, R4 represents a atom hydrogen or an alkyl, cyanalkyl or hydroxyalkyl group, R5 represents a hydrogen atom or an alkyl or aryl group, and A © represents a monovalent anion, characterized in that a compound of formula (II) is treated with an alkylating agent ) N = N- H <T Cationic dyes of the pyrazolium-indole type have already been described in French patent 1,486,066 filed on July 6, 1966. These known dyes are derived from 5-amino pyrazoles having no aryl group in position 3 except s d 'an example which describes a dye having two aryl groups in position 1 and 3 of the pyrazolium nucleus. It has been found that the pyrazolium-indole dyes carrying an alkyl group in position 1 of the pyrazolium nucleus and an aryl group in position 3 of this same nucleus have vis-à-1 "vis-à-vis synthetic fibers of acidic nature and in particular those based polymers or copolymers of acrylic nitrile, a much better affinity than the dyes described in French patent 1,486,066 and provide on these fibers pure and lively shades endowed with a set of excellent solidities. By better affinity is meant a better rise power on the fibers, which leads to better exhaustion of the dye baths. The alkyl groups preferably contain 1 to 5 carbon atoms. The aryl group is preferably the phe-nyl group. The alkylating treatment can be carried out in organic solvents, such as benzene hydrocarbons and their chlorinated derivatives, dimethylformamide or chloroform. It is also possible to operate in an excess of alkylating agent. As alkylating agents, there can be used, for example, alkyl halides, alkyl arylsulfonates, alkyl sulfates, in particular methyl and ethyl salts. The compounds of formula (II) can be prepared by coupling the diazo derivative of a phenyl-3 (5) amino-5 (3) pyrazole of general formula: (III) (II). in which X, R3, R4 and R5 have the same meanings as above. 2. Dyes of formula (I) produced by the process according to claim 1. with an indole of formula: