Azo dyes with a coupling component of the quinoline series

Abstract

Azo dyes useful for dyeing or printing textile fibers or fabrics and for thermal transfer have the formula ##STR1## where R.sup.1 and R.sup.2 are each substituted or unsubstituted C.sub.1 -C.sub.10 -alkyl or substituted or unsubstituted C.sub.3 -C.sub.4 -alkenyl or R.sup.1 may also be hydrogen,R.sup.3 is hydrogen or C.sub.1 -C.sub.6 -alkyl,R.sup.4 and R.sup.5 are each hydrogen, C.sub.1 -C.sub.6 -alkyl, halogen, C.sub.1 -C.sub.6 -alkoxy, amino or mono- or di(C.sub.1 -C.sub.4 -alkyl)amino, andD is a radical of the thiophene, thiazole, isothiazole, benzothiophene, thienothiophene or thienothiazole series.

Description

The present invention relates to novel azo dyes of the formula I ##STR2## where R.sup.1 and R.sup.2 are identical or different and each is independently of the other C.sub.1 -C.sub.10 -alkyl, which may be interrupted by 1 or 2 oxygen atoms in ether function and may be substituted by phenyl, cyano, C.sub.1 -C.sub.4 -alkoxycarbonyl, C.sub.1 -C.sub.4 -alkoxycarbonyloxy, hydroxyl or C.sub.1 -C.sub.4 -alkanoyloxy, or unsubstituted or chlorine-substituted C.sub.3 -C.sub.4 -alkenyl, or R.sup.1 may also be hydrogen,

R.sup.3 is hydrogen or C.sub.1 -C.sub.6 -alkyl, R.sup.4 and R.sup.5 are identical or different and each is independently of the other hydrogen, C.sub.1 -C.sub.6 -alkyl, halogen, C.sub.1 -C.sub.6 -alkoxy, amino or mono- or di(C.sub.1 -C.sub.4 -alkyl)amino, and D is a radical of the formula ##STR3## where L.sup.1 is cyano, C.sub.1 -C.sub.6 -alkanoyl, benzoyl, C.sub.1 -C.sub.4 -alkoxycarbonyl, C.sub.1 -C.sub.6 -alkylsulfonyl, substituted or unsubstituted phenylsulfonyl or a radical of the formula --CH.dbd.C(CN).sub.2 or --CH.dbd.C(CN)--COOX, where X is C.sub.1 -C.sub.4 -alkyl, L.sup.2 is halogen, unsubstituted or phenyl- or C.sub.1 -C.sub.4 -alkoxy-substituted C.sub.1 -C.sub.6 -alkoxy, substituted or unsubstituted phenoxy, unsubstituted or phenyl-substituted C.sub.1 -C.sub.6 -alkylthio, substituted or unsubstituted phenylthio, C.sub.1 -C.sub.6 -alkylsulfonyl, substituted or unsubstituted phenylsulfonyl or C.sub.1 -C.sub.4 -alkoxycarbonyl, L.sup.3 is cyano or C.sub.1 -C.sub.4 -alkoxycarbonyl, L.sup.4 is cyano, C.sub.1 -C.sub.6 -alkanoyl, benzoyl, C.sub.1 -C.sub.6 -alkylsulfonyl, substituted or unsubstituted phenylsulfonyl or a radical of the formula --CH.dbd.C(CN).sub.2 or --CH.dbd.C(CN)--COOX, where X is C.sub.1 -C.sub.4 -alkyl, L.sup.5 is hydrogen, C.sub.1 -C.sub.6 -alkyl, halogen, unsubstituted or phenyl- or C.sub.1 -C.sub.4 -alkoxy-substituted C.sub.1 -C.sub.6 -alkoxy, unsubstituted or phenyl-substituted C.sub.1 -C.sub.6 -alkylthio, substituted or unsubstituted phenylthio, C.sub.1 -C.sub.6 -alkylsulfonyl, substituted or unsubstituted phenylsulfonyl or C.sub.1 -C.sub.4 -alkoxycarbonyl, L.sup.6 is cyano, unsubstituted or phenyl-substituted C.sub.1 -C.sub.6 -alkyl, C.sub.1 -C.sub.6 -alkylthio, substituted or unsubstituted phenyl, thienyl, C.sub.1 -C.sub.4 -alkylthienyl, pyridyl or C.sub.1 -C.sub.4 -alkylpyridyl, L.sup.7 is cyano, C.sub.1 -C.sub.4 -alkoxycarbonyl, halogen or thiocyanato, L.sup.8 is hydrogen, cyano or halogen and L.sup.9 is C.sub.1 -C.sub.6 -alkanoyl or C.sub.1 -C.sub.4 -alkoxycarbonyl, and the use thereof for dyeing or printing textile fibers or fabrics or for thermal transfer.

JP-A-65 481/1978 discloses azo dyes whose diazo components are derived from 2-aminothiophenes and whose coupling components are derived from 8-aminoquinolines. However, it has been found that the dues mentioned therein still have defects in their application properties.

It is an object of the present invention to provide novel azo dyes which likewise have a coupling component of the 8-aminoquinoline series and whose diazo component is a member of the heterocyclic series. The novel dyes shall be characterized by an advantageous application property profile.

We have found that this object is achieved by the azo dyes of the formula I defined at the beginning.

Substituted phenyl appearing in the radicals of the abovementioned formula I may have for example C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -alkoxy or halogen, in particular chlorine or bromine, as substituents. If substituted, the phenyl rings will in general have from 1 to 3 substituents.

Any alkyl or alkenyl appearing in the above-mentioned formulae may be either straight-chain or branched.

R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, L.sup.5 and L.sup.6 are each for example methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, pentyl, isopentyl, neopentyl, tert-pentyl, hexyl or 2-methylpentyl.

R.sup.1, R.sup.2 and L.sup.6 may each also be benzyl or 1- or 2-phenylethyl.

L.sup.2, L.sup.5 and L.sup.6 may each also be for example methylthio, ethylthio, propylthio, isopropythio, butylthio, isobutylthio, pentylthio, hexylthio, benzylthio, 1- or 2-phenylethylthio, phenylthio, 2-methylphenylthio, 2-methoxyphenylthio or 2-chlorophenylthio.

L.sup.2 and L.sup.5 and also R.sup.4 and R.sup.5 may each also be for example methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutyoxy, sec-butoxy, pentyloxy, isopentyloxy, neopentyloxy, tert-pentyloxy, hexyloxy or 2-methylpentyloxy.

R.sup.4, R.sup.5, L.sup.2 and L.sup.5 and also L.sup.7 and L.sup.8 may each also be for example fluorine, chlorine or bromine.

L.sup.1, L.sup.2 and L.sup.5 and also L.sup.4 may each also be for example methylsulfonyl, ethylsulfonyl, propylsulfonyl, isopropylsulfonyl, butylsulfonyl, isobutylsulfonyl, sec-butylsulfonyl, pentylsulfonyl, isopentylsulfonyl, neopentylsulfonyl, hexysulfonyl, phenylsulfonyl, 2-methylphenylsulfonyl, 2-methoxyphenylsulfonyl or 2-chlorophenylsulfonyl.

L.sup.1, L.sup.2, L.sup.5 and L.sup.7 and also L.sup.3 and L.sup.9 may each also be for example methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl or sec-butoxycarbonyl.

L.sup.2 and L.sup.5 may each also be for example 2-methoxyethoxy, 2-ethoxyethoxy, 2- or 3-methoxypropoxy, 2- or 3-ethoxypropoxy, 2- or 4-methoxybutyoxy, 2- or 4-ethoxybutoxy, 5-methoxypentyloxy, 5-ethoxypentyloxy, 6-methoxyhexyloxy, 6-ethoxyhexyloxy, benzyloxy or 1- or 2-phenylethoxy.

R.sup.4 and R.sup.5 may each also be for example mono- or dimethylamino, mono- or diethyamino, mono, or dipropylamino, mono- or diisopropylamino, mono- or dibutylamino or N-methyl-N-ethylamino.

L.sup.6 may also be for example phenyl, 2-, 3- or 4-methylphenyl, 2,4-dimethylphenyl, 2-, 3- or 4-chlorphenyl, 2-, 3- or 4-methoxyphenyl, 2- or 3-methylthienyl or 2-, 3- or 4-methylpyridyl.

L.sup.1, L.sup.4 and L.sup.9 may each also be for example formyl, acetyl, propionyl, butyryl, isobutylryl, pentanoyl or hexanoyl.

R.sup.1 and R.sup.2 may each also be for example heptyl, octyl, 2-ethylhexyl, isooctyl, nonyl, isononyl, decyl, cyanomethyl, 2-cyanoethyl, 3-cyanopropyl, 2-cyanobutyl, 4-cyanobutyl, 5-cyanopentyl, 6-cyanohexyl, 2-hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl, 2-hydroxybutyl, 4-hydroxybutyl, 5-hydroxypentyl, 6-hydroxyhexyl, 2-methoxyethyl, 2-ethoxyethyl, 2-propoxyethyl, 2-isopropoxyethyl, 2-butoxyethyl, 2- or 3-methoxypropyl, 2- or 3-ethoxypropyl, 2- or 3-propoxypropyl, 2- or 3-butoxypropyl, 2- or 4-methoxybutyl, 2- or 4-ethoxybutyl, 2- or 4-propoxybutyl, 2- or 4-butoxybutyl, 3,6-dioxaheptyl, 3,6-dioxaoctyl, 4,8-dioxanonyl, 3,7-dioxaotyl, 3,7-dioxanonyl, 4,7-dioxaoctyl, 4,7-dioxanonyl, 4,8-dioxadecyl, methoxycarbonylmethyl, ethoxycarbonylmethyl, 2-methoxycarbonylethyl, 2-ethoxycarbonylethyl, 3-methoxycarbonylpropyl, 3-ethoxycarbonylpropyl, 4-methoxycarbonylbutyl, 4-ethoxycarbonylbuty, 5-methoxycarbonylpentyl, 5-ethoxycarbonylpentyl, 6-methoxycarbonylhexyl, 6-ethoxycarbonylhexyl, 2-methoxycarbonyloxyethyl, 2-ethoxycarbonyloxyethyl, 2- or 3-methoxycarbonyloxypropyl, 2- or 3-ethoxycarbonyloxypropyl, 2-acetyloxyethyl, 2-propionyloxyethyl, 2- or 3-acetyloxypropyl, 2- or 3-propoxyloxypropyl, 2- or 4-acetyloxybutyl, 2- or 4-propionyloxybutyl, prop-2-en-1-yl, but-2-en-1-yl, 2-methylprop-2-en-1-yl, 3-chloroprop-2-en-1-yl or 4-chlorobut-2-en-1-yl.

Preference is given to azo dyes of the formula I where R.sup.3 is hydrogen or methyl and R.sup.4 and R.sup.5 are each hydrogen.

Preference is further given to azo dyes of the formula I where D is a radical of the formula ##STR4## where L.sup.1, L.sup.2 and L.sup.3 are each as defined above.

Particular preference is given to azo dyes of the formula I where R.sup.1 is hydrogen, R.sup.2 is C.sub.1 -C.sub.10 -alkyl, which may be interrupted by 1 oxygen atom in ether function and may be substituted by phenyl, cyano, C.sub.1 -C.sub.4 -alkoxycarbonyl or hydroxyl, R.sup.3 is hydrogen or methyl, and R.sup.4 and R.sup.5 are each hydrogen.

Particular preference is further given to azo dyes of the formula I where D is a radical of the formula ##STR5## where L.sup.1 is cyano, formyl or a radical of the formula --CH.dbd.C(CN).sub.2 or --CH.dbd.C(CN)--COOX, where X is as defined above,

L.sup.2 is chlorine or C.sub.1 -C.sub.4 -alkoxycarbonyl, and L.sup.3 is cyano or C.sub.1 -C.sub.4 -alkoxycarbonyl.

Of particular interest are azo dyes of the formula I where D is the radical of the formula ##STR6## where L.sup.1 is formyl or a radical of the formula --CH.dbd.C(CN).sub.2 or --CH.dbd.C(CN)--COOX, where X is as defined above.

The novel azo dyes of the formula I can be obtained in a conventional manner, for example by diazotizing an amine of the formula II

D--NH.sub.2 (II) where D is as defined above, in a conventional manner and coupling it with a coupling component of the formula III ##STR7## where R.sup.1, R.sup.2, R.sup.3, R.sup.4 and R.sup.5 are each as defined above.

When L.sup.1 or L.sup.4 is the radical --CH.dbd.C(CN).sub.2 or --CH.dbd.C(CN)--COOX, the diazotization is carried out with those 2-aminothiophene or 2-aminothiazole derivatives which already contain these groups in the molecule or it is carried out with the corresponding formyl derivatives and, after the coupling reaction, followed by condensing with malodinitrile or C.sub.1 -C.sub.4 -alkyl cyanoacetate.

The amines of the formula II and the coupling components of the formula III are in general compounds known per se. Diazo components of the aminothienothiophene or aminothienothiazole series are described for example in U.S. Pat. No. 4,843,153 or GB-A-1 546 803.

The azo dyes of the formula I according to the present invention are advantageously useful as disperse dyes for dyeing or printing textile fibers or fabrics, in particular polyesters, but also fibers or fabrics made of cellulose esters or polyamides or blend fabrics composed of polyester and cellulose fibers.

To obtain a favorable color buildup it can be advantageous in some cases to use mixtures of the dyes of the formula I with one another.

The novel azo dyes are characterized by high color strength, good fastness properties and brilliant hues.

The azo dyes according to the present invention are also advantageously useful for thermal transfer from a transfer to a plastic-coated paper by means of an energy source (see for example EP-A-416 434).

The invention will now be more particularly described by the following Examples:

EXAMPLE 1

a) 4.40 g (0.02 mol) of 2-amino-3-cyano-4-chloro-5-formylthiophene were dissolved in 20 ml of 96% by weight sulfuric acid, and the solution was stirred at from 25.degree. to 30.degree. C. for 1 hour. 6.60 g of nitrosylsulfuric acid (11.5% of N.sub.2 O.sub.3) were then added dropwise at from 0.degree. to 5.degree. C., and the mixture was stirred at from 0.degree. to 5.degree. C. for 2.5 hours.

b) 5.40 g (0.021 mol) of 2-methyl-8-(2-methoxycarbonylethylamino)quinoline were dissolved in 500 ml of water and 5 ml of 96% by weight sulfuric acid, introduced as initial charge together with 0.50 g of amidosulfuric acid and 300 g of ice and admixed at not more than 5.degree. C. with the diazonium salt solution described under a). After the coupling reaction had ended, the dye was filtered off with suction at 60.degree. C., washed neutral and dried. This gave 8.00 g (90.6% of theory) of the dye of the formula ##STR8## which dyes polyester fibers in a fast blue shade.

EXAMPLE 2

a) 4.60 g (0.025 mol) of 2-amino-3,5-dicyano-4-chlorothiophene in 100 ml of 3:1 (v/v) of glacial acetic acid/propionic acid and 25 ml of 85% by weight sulfuric acid were admixed at not more than 5.degree. C. with 6.80 g of nitrosylsulfuric acid (11.5% of N.sub.2 O.sub.3) and the mixture was stirred at from 0.degree. to 5.degree. C. for 3 hours.

b) 7.10 g (0.027 mol) of 2-methyl-8-(2-methoxycarbonylethylamino)quinoline were dissolved in 500 ml of water and 5 ml of 96% by weight sulfuric acid, introduced as initial charge together with 0.50 g of amidosulfuric acid and 300 g of ice and admixed at not more than 5.degree. C. with the diazonium salt solution described under a). After the coupling reaction had ended, the dye was filtered off with suction at 60.degree. C., washed neutral and dried. This gave 8.0 g (90.6% of theory) of the dye of the formula ##STR9## which dyes polyester in a blue shade.

The procedures of Examples 1 and 2 are followed to obtain the dyes listed in the following Tables 1 to 3:

TABLE 1__________________________________________________________________________ ##STR10##Example Color onNo. L.sup.1 L.sup.2 L.sup.3 K polyester__________________________________________________________________________ 3 CHO Cl CN ##STR11## blue 4 CHO Cl CN ##STR12## blue 5 CHO Cl CN ##STR13## blue 6 CHO Cl CN ##STR14## blue 7 CHO Cl CN ##STR15## blue 8 CHO Cl CN ##STR16## blue 9 CHO Cl CN ##STR17## blue10 CHO Cl CN ##STR18## blue11 CHO Cl CN ##STR19## blue12 CHO Cl CN ##STR20## blue13 CHO Cl CN ##STR21## blue14 CHO Cl CN ##STR22## blue15 CHO Cl CN ##STR23## blue16 CHO Cl CN ##STR24## blue17 CHO Cl CN ##STR25## blue18 CHO Cl CN ##STR26## blue19 CN Cl CN ##STR27## blue20 CN Cl CN ##STR28## blue21 CN Cl CN ##STR29## blue22 CH.sub.3 OOC CH.sub.3 OOC CN ##STR30## blue23 CH.sub.3 OOC CH.sub.3 OOC CN ##STR31## blue24 CH.sub.3 OOC CH.sub.3 OOC CN ##STR32## reddish blue25 CN Cl CN ##STR33## blue26 CHO Cl CN ##STR34## blue27 CN Cl CN ##STR35## blue28 CN Cl CN ##STR36## blue29 CN Cl CN ##STR37## blue30 CN Cl CN ##STR38## blue31 CN Cl CN ##STR39## blue32 CN Cl CN ##STR40## blue__________________________________________________________________________ TABLE 2__________________________________________________________________________ ##STR41##Example Color onNo. Q K polyester__________________________________________________________________________33 CH.sub.3 CO ##STR42## blue34 CH.sub.3 CO ##STR43## blue35 CH.sub.3 CO ##STR44## blue36 C.sub.2 H.sub.5 OOC ##STR45## blue37 C.sub.2 H.sub.5 OOC ##STR46## blue38 C.sub.2 H.sub.5 OOC ##STR47## blue__________________________________________________________________________ TABLE 3__________________________________________________________________________ ##STR48##Example Color onNo. Q K polyester__________________________________________________________________________39 CH.sub.3 CO ##STR49## blue40 CH.sub.3 CO ##STR50## blue41 CH.sub.3 CO ##STR51## blue42 CH.sub.3 CO ##STR52## blue43 CH.sub.3 OOC ##STR53## blue44 CH.sub.3 OOC ##STR54## blue45 CH.sub.3 OOC ##STR55## blue46 CH.sub.3 OOC ##STR56## blue__________________________________________________________________________ p The diazo components of the dyes listed above in Table 2 were obtained as follows:

EXAMPLE 47

81.2 g of 2-amino-4-chloro-5-formylthiazole were dissolved in 400 ml of N,N-dimethylformamide. 60 g of potassium carbonate were added, followed at room temperature by 54.6 ml of ethyl thioglycolate, added dropwise. After the exothermic reaction had ceased, the reaction mixture was stirred at 60.degree. C. for 3 hours. It was then discharged onto 1.5 l of ice-water, and the precipitate was filtered off with suction, washed with water and dried under reduced pressure at 50.degree. C. This gave 79.8 g (70% of theory) of the compound of the formula ##STR57## of melting point 98.degree. C.

The same method can be used to obtain the corresponding methoxycarbonyl compound (mp. 238.degree. C.) or the acetyl compound (mp. 259.degree.-60.degree. C.).

EXAMPLE 48

a) 6.40 g (0.025 mol) of 3-benzyl-4-cyano-5-aminoisothiazole were added at 35.degree. C. to a mixture of 13.0 g of ice and 35.0 g of 96% by weight sulfuric acid. After 8.0 g of nitrosylsulfuric acid (11.5% of N.sub.2 O.sub.3) had been added, the mixture was stirred at from 0.degree. to 5.degree. C. for 3 hours.

b) 6.0 g (0.028 mol) of 2-methyl-8-(2-cyanoethylamino)quinoline were dissolved in 500 ml of water and 5 ml of 96% by weight sulfuric acid, introduced as initial charge together with 0.50 g of amidosulfuric acid and 300 g of ice and admixed at not more than 5.degree. C. with the diazonium salt solution described under a). After the coupling reaction had ended, the dye was filtered off with suction at from 40.degree. to 60.degree. C., washed neutral and dried. This gave 7.6 g (70% of theory) of the dye of the formula. ##STR58## in the form of a black powder (mp. 201.degree.-204.degree. C.). The dye gives a light-fast violet shade on polyester fibers.

The same method can be used to obtain the dyes listed in the following Tables 4 and 5:

TABLE 4__________________________________________________________________________ ##STR59##Example Color onNo. L.sup.6 K polyester__________________________________________________________________________49 H.sub.5 C.sub.6 CH.sub.2 ##STR60## violet50 H.sub.5 C.sub.6 CH.sub.2 ##STR61## violet51 H.sub.5 C.sub.6 CH.sub.2 ##STR62## violet52 H.sub.5 C.sub.6 CH.sub.2 ##STR63## violet53 H.sub.5 C.sub.6 CH.sub.2 ##STR64## violet54 H.sub.5 C.sub.6 CH.sub.2 ##STR65## violet55 C.sub.6 H.sub.5 ##STR66## violet56 i-C.sub.3 H.sub.7 ##STR67## violet57 i-C.sub.3 H.sub.7 ##STR68## violet__________________________________________________________________________ TABLE 5__________________________________________________________________________ ##STR69##Example Color onNo. L.sup.4 L.sup.5 K polyester__________________________________________________________________________58 CHO Cl ##STR70## blue59 CHO Cl ##STR71## blue60 CHO Cl ##STR72## blue61 CHO Cl ##STR73## blue62 CHO Cl ##STR74## blue63 CN CH.sub.3 OOC ##STR75## violet64 CN CH.sub.3 OOC ##STR76## violet65 CN CH.sub.3 OOC ##STR77## violet66 CN Cl ##STR78## reddish blue67 CN Cl ##STR79## reddish blue68 CN Cl ##STR80## reddish blue69 CHO Cl ##STR81## blue70 CHO Cl ##STR82## blue71 CHO Cl ##STR83## blue72 CN Cl ##STR84## blue73 CN Cl ##STR85## blue74 CN Cl ##STR86## blue75 CHO Cl ##STR87## blue76 CN Cl ##STR88## blue77 CHO Cl ##STR89## blue78 CN Cl ##STR90## blue__________________________________________________________________________

EXAMPLE 79

2.36 g (0.005 mol) of the dye of Example 6 were dissolved in 20 ml of glacial acetic acid, admixed with 0.40 g (0.006 mol) of malodinitrile and heated at 80.degree. C. for 1 hour. Then 20 ml of water were added, the mixture was stirred for 15 minutes, and the precipitate was filtered off with suction, washed with 50 ml of 50% by weight aqueous acetic acid and then with water and dried under reduced pressure at 50.degree. C. This gave 2.45 g of the dye of the formula ##STR91## in the form of a greenish powder which dyes polyester fibers in a greenish blue shade.

EXAMPLE 80

a) 66 g (0.3 mol) of 2-amino-3-cyano-4-chloro-5-formylthiophene were dissolved in 500 ml of glacial acetic acid, admixed with 23.80 g (0.36 mol) of malodinitrile and heated at 118.degree. C. for 6.5 hours. The mixture was then cooled down and filtered with suction at room temperature. Washing the filter residue with 100 ml of glacial acetic acid, washing neutral with water and drying at 40.degree. C. under reduced pressure left 72.1 g of the diazo component of the formula ##STR92##

b) 5.90 g (0.025 mol) of the 2-amino-3-cyano-4-chloro-5-(2,2-dicyanovinyl)thiophene described under a) were dissolved in 100 ml of 3:1 (v/v) glacial acetic acid/propionic acid and 20 ml of 85% by weight sulfuric acid, admixed at from 0.degree. to 5.degree. C. with 7.8 g of nitrosylsulfuric acid (11.5% of N.sub.2 O.sub.3) and stirred at from 0.degree. to 5.degree. C. for 2 hours.

c) 8.00 g (0.035 mol) of 2-methyl-8-(2-methoxycarbonylethylamino)quinoline were dissolved in 150 ml of water and 2 ml of 96% by weight sulfuric acid and admixed with 0.5 g of amidosulfuric acid and also 300 g of ice. The diazonium salt solution described under b) was added dropwise at from 0.degree. to 5.degree. C. in the course of 10 minutes. After the coupling reaction had ended, the dye was filtered off with suction at 60.degree. C., washed neutral and dried under reduced pressure at 50.degree. C. This gave 7.70 g of the dye of the formula ##STR93## which dyes polyester fibers in a greenish blue shade.

The procedures of Examples 79 and 80 are followed to obtain the dyes listed in the following Table 6:

TABLE 6__________________________________________________________________________ ##STR94##Example Color onNo. T.sup.1 T.sup.2 K polyester__________________________________________________________________________81 CN CN ##STR95## greenish blue82 CN C.sub.2 H.sub.5 OOC ##STR96## greenish blue83 CN C.sub.2 H.sub.5 OOC ##STR97## greenish blue84 CN C.sub.2 H.sub.5 OOC ##STR98## greenish blue85 CN C.sub.4 H.sub.9 OOC ##STR99## greenish blue86 CN CN ##STR100## greenish blue__________________________________________________________________________

Transfer of dyes (use)

General method:

a) 10 g of dye are stirred at 20.degree. C. into 100 g of a 10% by weight solution of a binder (Vylon.RTM. 290 from Toyobo) in 4.5:2:2 v/v/v methyl ethyl ketone/toluene/cyclohexanone.

The printing ink is applied with a 6 .mu.m draw bar to a 6 .mu.m thick polyester film coated on the back with a suitable slipping layer and dried with a hair dryer in the course of 1 minute. Before the color ribbon can be printed, it has to afterdry in air for at least 24 hours, since residual solvent can have an adverse effect on the printing process.

b) The color ribbons are printed onto Hitachi VY-S video print paper in a computer-controlled experimental arrangement equipped with a commercial thermal head.

By varying the voltage it is possible to control the energy emitted by the thermal head, the pulse duration setting being 7 ms and only one pulse being emitted at any one time. The emitted energy is within the range from 0.71 to 1.06 mJ/dot.

Since the depth of shade is directly proportional to the supplied energy, a color wedge can be produced and evaluated spectroscopically.

A plot of the depth of shade versus the supplied energy is used to determine the Q* value (=energy in mJ/dot for the absorbance value 1) and the slope m in 1/mJ.

The results obtained are listed in the following Table 7:

TABLE 7______________________________________ .lambda..sub.max [nm]Example Dye (measured Q* mNo. No. in CH.sub.2 Cl.sub.2) [mJ/dot] [1/mJ]______________________________________87 3 623 0.99 2.1088 11 622 0.94 2.3489 6 616 1.31 1.3290 1 609 1.36 1.2091 7 595 1.78 0.8392 16 616 1.54 1.0493 17 616 1.22 1.4194 85 672 1.08 2.0695 86 692 1.17 1.73______________________________________

Claims

1. An azo dye of the formula I ##STR101## where R.sup.1 and R.sup.2 are identical or different and each is independently of the other C.sub.1 -C.sub.10 -alkyl, which may be interrupted by 1 or 2 oxygen atoms in ether function and may be substituted by phenyl, cyano, C.sub.1 -C.sub.4 -alkoxycarbonyl, C.sub.1 -C.sub.4 -alkoxycarbonyloxy, hydroxyl or C.sub.1 -C.sub.4 -alkanoyloxy, or unsubstituted or chlorine-substituted C.sub.3 -C.sub.4 -alkenyl, or R.sup.1 may also be hydrogen,

R.sup.3 is hydrogen or C.sub.1 -C.sub.8 -alkyl,

R.sup.4 and R.sup.5 are identical or different and each is independently of the other hydrogen, C.sub.1 -C.sub.6 -alkyl, halogen, C.sub.1 -C.sub.6 -alkoxy, amino or mono- or di(C.sub.1 -C.sub.4 -alkyl)amino, and

D is a radical of the formula ##STR102## where L.sup.1 is cyano, C.sub.1 -C.sub.6 -alkanoyl, benzoyl, C.sub.1 -C.sub.4 -alkoxy-carbonyl, C.sub.1 -C.sub.6 -alkylsulfonyl, substituted or unsubstituted phenylsulfonyl or a radical of the formula --CH.dbd.C(CN).sub.2 or --CH.dbd.C(CN)--COOX, where X is C.sub.1 -C.sub.4 -alkyl,

L.sup.2 is halogen,

L.sup.3 is cyano or C.sub.1 -C.sub.4 -alkoxycarbonyl,

L.sup.4 is cyano, C.sub.1 -C.sub.6 -alkanoyl, benzoyl, C.sub.1 -C.sub.6 -alkylsulfonyl, substituted or unsubstituted phenylsulfonyl or a radical of the formula --CH.dbd.C(CN).sub.2 or --CH.dbd.C(CN)--COOX, where X is C.sub.1 -C.sub.4 -alkyl,

L.sup.5 is hydrogen, C.sub.1 -C.sub.6 -alkyl, halogen, unsubstituted or phenyl- or C.sub.1 -C.sub.4 -alkoxy-substituted C.sub.1 -C.sub.6 -alkoxy, unsubstituted or phenyl-substituted C.sub.1 -C.sub.6 -alkylthio, substituted or unsubstituted phenylthio, C.sub.1 -C.sub.6 -alkylsulfonyl, substituted or unsubstituted phenylsulfonyl or C.sub.1 -C.sub.4 -alkoxycarbonyl,

L.sup.6 is cyano, unsubstituted or phenyl-substituted C.sub.1 -C.sub.6 alkyl, C.sub.1 -C.sub.6 -alkylthio, substituted or unsubstituted phenyl thienyl, C.sub.1 -C.sub.4 -alkylthienyl, pyridyl or C.sub.1 -C.sub.4 -alkylpyridyl,

L.sup.7 is cyano, C.sub.1 -C.sub.4 -alkoxycarbonyl, halogen or thio-cyanato,

L.sup.8 is hydrogen, cyano or halogen and

L.sup.9 is C.sub.1 -C.sub.6 -alkanoyl or C.sub.1 -C.sub.4 -alkoxycarbonyl.

2. An azo dye as claimed in claim 1, wherein R.sup.3 is hydrogen or methyl and R.sup.4 and R.sup.5 are each hydrogen.

3. An azo dye as claimed in claim 1, wherein D is a radical of the formula ##STR103## where L.sup.1, L.sup.2 and L.sup.3 are each as defined in claim 1.

4. An azo dye as claimed in claim 1, wherein L.sup.2 is chloro.