GB2054630A - Triazolopyridine dyes - Google Patents

Abstract

These dyestuffs have the formula T - N = N - E wherein T is a residue of a s-triazolo-[4,3-a]- or [5,1-a]-pyridine and E is the residue of a coupling component, and may be used as disperse dyes. In addition, water soluble azo dyestuffs free from carboxylic acid and sulphonic acid groups which are cationic derivatives of these dyestuffs are prepared by quaternising the dye base and are useful for colouring polyacrylonitrile fibres. The dyes are bright violet and have good fastness properties.

Description

SPECIFICATION Triazolopyridine dyes This invention relates to azo dyestuffs derived from triazolo pyridines.

According to the present invention we provide an azio dyestuff having the formula T-N=N-E wherein T is the residue of a s-triazolo-[4,3-a]- or [5,1-a]-pyridine and E is the residue of a coupling component, especially a p-coupling amine.

More particularly T has the formula:

in which the pyridine ring B may carry substituents such as those normally present in dyestuffs molecules.

Such a dyestuff, free of water solubilising groups, may be used as a disperse dye. However, in a preferred aspect of our invention we provide a water soluble azo dyestuff free of carboxylic acid and sulphonic acid groups which is a cationic derivative of the dyestuff or dye base hereinbefore described and has the formula: [T1 - N = N - E]o AO wherein T' is the residue of a quaternised s-triazolo-[4,3-a]- or [5,1-a]-pyridine, E has the meaning hereinbefore defined and A is an anion.

More particularly T1 has the formula:

wherein B has the meaning herein before defined and R is hydrogen or an optionally substituted alkyl, cycloalkyl, aryl or aralkyl group and, in the case of the s-tnazolo-[4,3-a]-pyridine residue, is attached to the 1- or 2-nitrogen atom. A quaternised dyestuff containing the s-triazolo-[4,3-a]pyridine residue will normally be a mixture of the delocalised bathochromic 2,4-isomer and the localised hypsochromic 1,4-isomer, the former predominating.

E may be the residue of any aromatic carbocyclic or heterocyclic coupling component including coupling components which couple by virtue of the presence of an enolic or amino group.

Examples of aromatic carbocyclic coupling components include amines of the formula:

wherein R' and R2 are independently hydrogen or an optionally substituted alkyl, aryl, aralkyl, alkenyl or cycloalkyl group or wherein R' and R2 taken together form a heterocyclic ring with the nitrogen atom.Such coupling components may contain a fused benz ring and be, for example, of the type:

Examples of R' and R2 include hydrogen, methyl, ethyl, propyl, butyl, phenyl, hydroxy lower alkyl such as 2-hydroxyethyl and 2- or 3-hydroxypropyl, lower alkoxy lower alkyl such as 2 (methoxy or ethoxy)ethyl and 3-methoxypropyl, cyano lower alkyl such as 2-cyanoethyl, aryl lower alkyl such as benzyl and fi-phenylethyl, alkoxy lower alkyl such as 2-acetoxyethyl, lower alkoxycarbonyl, lower alkyl such as 2-methoxycarbonylethyl, hydroxy-, lower alkoxy-, lower alkyl such as 2-(2'-hydroxyethoxy)ethyl, lower alkoxy-, lower alkoxycarbonyl-, lower alkyl such as 2 (2'-methoxyethoxycarbonyl)ethyl, 2-carbamoylethyl, cycioalky such as cyclohexyl, hyd roxyary- loxy-, lower alkyl such as hydroxyphenoxyethyl and cycloalkoxy-, lower alkyl such as cyclohexyloxyethyl.

Examples wherein R' and R2 form a heterocyclic ring with the nitrogen atom include as the so-formed heterocyclic rings, morpholino, pyrrolidino and piperidino rings.

The benzene ring in coupling components of the type:

may be further substituted particularly in the 2 and 5 positions relative to the amino group, for example to give coupling components of the formula:

wherein R' and R2 are as hereinbefore defined; R3 is hydrogen, lower alkyl such as methyl, ethyl, propyl or butyl; lower alkoxy such as methoxy and ethoxy or halogen such as chlorine or bromine, and R4 is hydrogen, lower alkyl such as methyl, ethyl, propyl or butyl, lower alkoxy such as methoxy, ethoxy, propoxy or butoxy, halogen such as chlorine or bromine, carbalkoxy such as methoxycarbonyl and ethoxycarbonyl; acyl such as methyl-, ethyl, and phenylcarbonyl, and methyl-, ethyl- and phenylsulphonyl; nitro, cyano, trifluoromethyl, thiocyano; acylamino such as formamide, acetylamino, propionylamino, phenyl-, ethyl- and methyl-sulphonylamino; sulphonamido, aikylsulphonamido such as methyl-, ethyl-, dimethyl- and diethylsulphonamido, carbonamido and alkyl-carbonamido such as methyl-, ethyl-, diethyl- and dimethylcarbonamido, aryl acid amides such as phenylcarbamoyl and phenylsulphamoyl and ureido.

Preferred examples of R3 include hydrogen, methyl, ethyl, methoxy, ethoxy and chloro.

Preferred examples of R4 include hydrogen, methyl, ethyl, methoxy, ethoxy, formamido, acetylamino, propionylamino, ureido, chloro and bromo.

Where the term "lower" is used in this specification in connection with alkyl or alkoxy it means an alkyl or alkoxy group having from one to four carbon atoms.

An additional para coupling amine from which E may be derived is that of formula:

wherein Y is a divalent radical forming a 5- or 6-membered ring with the N-atom and the two carbon atoms of the benzene ring, R' is as hereinbefore defined except that R' is not phenyl, and either or both of the rings may be substituted. These and other suitable coupling components are more fully described in our UK Patent No. 1508500.

Examples of substituents which may be present in the pyridine ring B include halogen atoms for example chloro, bromo and fluoro, alkoxy for example methoxy and ethoxy, alkyl for example me-hyl, acylamino for example acetylamino, alkoxycarbonyl for example methoxycarbonyl, nitro, acyloxy for example acetoxy, aryloxy for example phenoxy, carbamyl for example diethylaminocarbonyl, amino for example methylamino, alkylsulphonyl, phenoxy sulphonyl, trifluoromethyl, alkoxycarbonylamino, dialkylaminosulphamyl, monoalkylaminosulphamyl, sulphamyl, acyl for example acetyl, cyano, arylazo and aryl for example phenyl.

R is preferably lower alkyl and especially methyl.

As anions represented by AG there may be mentioned, for example, anions of inorganic acids such as chloride, bromide, tetrachlorozincate, bisulphate, sulphate, tetrafluoroborate, sulphamate, nitrate, phosphate and fluoride and anions of organic acids such as methosulphate, ethosulphate, methyl sulphonate, p-tolyl sulphonate, acetate, oxalate, hydrogen oxalate and formate. In those cases where the anion is polyvalent the water-soluble dyestuffs will contain a corresponding molar proportion of the cationic part of the dyestuff.

In another aspect of our invention we provide a process for the manufacture of a dyestuff of the present invention which comprises diazotising an amine TNH2 and reacting the diazonium compound so formed with a compound EH wherein T and E have the meanings hereinbefore defined.

The amines embrace 3-amino-s-triazolo-[4, 3-a]-pyridine and 3-amino-s-triazolo-[5, l-a]-pyri- dine and substituted derivatives thereof. Examples of suitable substituents have already been described.

The 3-amino-s-triazolo-[4,3-a]-pyridines can be obtained by reacting cyanogen bromide with a 2-pyridyl hydrazine in methanol at low temperature. The 2-pyridyl hydrazine is itself obtained by reacting a 2-bromopyridine with hydrazine hydrate, raising the temperature from room temperature to boiling over half an hour, and extracting it from the reaction mixture with chloroform.

The 2-amino-s-triazolo-[5, 1-a]-pyridines are obtained by treating the appropriate 3-amino-s triazolo-[4,3-a]-pyridine hydrobromide with caustic liquor under reflux for two days. The product is finally extracted with chloroform.

Diazotisation of the amines is effected in aqueous solution with hydrochloric acid and sodium nitrite in the usuai way, excess nitrous acid being removed with sulphamic acid. The resulting solution of the diazo compound is added to a solution of the coupling component in hydrochloric acid, excess acidity being removed by addition of sodium acetate, and the resulting sticky oil extracted with chloroform. After drying the dyestuff can be separated on an Alumina 'O' column.

Suitable coupling components have also already been described and these are obtained by methods well known to those skilled in the dyestuffs field and described in the relevant literature.

The cationic dyestuff of the invention may be obtained by quaternising the dye base so obtained.

As examples of quaternising agents there may be mentioned alkyl halides such as methyl, ethyl, propyl, and butyl chlorides and the corresponding bromides, alkenyl halides such as allyl chloride or bromide, aralkyl halides such as benzyl chloride or bromide, dialkyl sulphates such as dimethyl sulphate, diethyl sulphate, dipropyl sulphate and dibutyl sulphate, alkyl esters of aryl sulphonates such as methyl and ethyl p-toluene sulphonate and other lower alkyl esters of strong mineral acids or organic sulphonates. Other alkylating agents may themselves carry substituents, for example chloropropionitrile bromopropionamide and bromohydrin.

The reaction between the quaternising agent and the compound of the above formula may be carried out neat without addition of other solvents, or again may be carried out in an inert organic solvent such as benzene, toluene, xylene, chlorobenzene, nitrobenzene, acetone, carbontetrachloride, tetrachloroethane, perchloroethylene, chloroform, dimethyl formamide, acetonitrile, acetic acid, formic acid or 2-ethoxyethanol. The quaternisation may also be effected in aqueous phase optionally in the presence of an organic solvent. The quaternising agent may be used in considerable excess, for example up to 6 moles for each mole of dyestuff. Suitable temperatures are from 20 to 1 50 C and particularly 20-90"C. The inclusion of an acid binding agent is often beneficial. Such agents include magnesium oxide, sodium and potassium carbonate, sodium and potassium bicarbonate, magnesium and calcium carbonate, potassium acetate or mixtures of such agents.

Quaternisation may also be carried out by reacting with, for example, acrylamide in an organic or mineral acid such as acetic, formic or hydrochloric acid or mixtures of these at between 50 and 100 C.

Quaternisation may also be carried out by reacting with ethylene oxide or its derivatives of formula:

wherein R5 and R6 represent hydrogen or an optionally substituted lower alkyl group.

This reaction is carried out in a solvent in the presence of a mineral or organic acid which provides the anion X, at temperatures of 10 to 1 00'C and preferably 40-90"C. Suitable acids include sulphuric, hydrochloric, hydrobromic, phosphoric, benzenesulphonic, toluenesulphonic, formic, acetic or propionic. Such acids may also serve as solvent or may be used in admixture with each other or with other organic solvent such as diemthylformamide, acetonitrile, dioxan, tetrahydrofuran, chlorobenzene, toluene, xylene, nitrobenzene, acetone or methylethylketone.

When the reaction is effected in hydrophobic organic solvents the quaternised dyestuff is normally insoluble and may be isolated by filtration. If desired, the quaternised dyestuff may be isolated from aqueous solution by precipitation in the form of a salt such as tetrachlorozincate obtained by adding zinc chloride to the aqueous solution.

As a result of the quaternisation the dyestuff may be obtained for example in the form of the chloride, bromide or methosulphate according to the alkylating agent used. If the dyestuff is required as the salt of a different anion, then one anion may be replaced by another by known methods, for example metathesis.

The dye base of the invention can be used as a disperse dye for colouring textile material, especially polyester material, by contacting the material with the dye by any conventional method. For instance, in the form of an aqueous dispersion the dye base can be applied by dyeing, padding or printing processes using the conditions and additives conventionally used, that is at temperatures of from 1 10'C to 140"C for 0.5 to 2 hours optionally in the presence of dispersing agents. Alternatively the dye can be applied by solvent methods, for example by applying to the material a solution or dispersion of the dye in a suitable solvent optionally containing a minor amount of water at elevated temperature.

The cationic dyestuff of the invention can be used for the colouration of paper and for the colouration of synthetic polymeric material by contacting the paper or polymeric material with the cationic dyestuff especially by application from an aqueous bath. The dyestuff gives bright violet shades.

In particular the cationic dyestuff of the invention is useful for colouring polyacrylonitrile materials and may be applied thereto from acid, neutral or slightly alkaline dyebaths (i.e. pH from 3-8) at temperatures between, for example 40 C and 1 20"C, preferably between 80"C and 1 20 C or by printing techniques using thickened printing pastes. Bright violet dyeings of good fastness properties are obtained.

The cationic dyestuff may also be used for the colouration of synthetic polymeric materials particularly polyacrylonitrile materials by wet transfer printing processes in which a support such as paper, is printed with an ink containing the dyestuff, the printed support is placed in contact with a textile material and the shole then subjected to heet and pressure under humid/wet conditions to transfer the dyestuff to the textile material.

The invention is illustrated by the following example in which all parts and percentages are by weight except where otherwise indicated. Where parts by volume are given, the relationship of weight to volume is the same as that between gram and millilitre.

Example Preparation of Intermediates Preparation of 3-amin o-s-triazolo-r4, 3-aJ-pyridin e (i) 2-Pyridyl hydrazine 2-Bromopyridine (78 parts; 0.5 moles) was added to hydrazine hydrate (375 parts by volume; 7.5 moles) at room temperature with stirring. The reaction mixture was then heated to boiling (105"C) over 30 minutes and maintained at this for 6 hours. The crude mixture was cooled to room temperature and extracted with chloroform (4 X 250 parts by volume).

The aqueous layers were reduced to a small volume by rotary evaporation before being made alkaline to Brilliant Yellow paper with 50% caustic liquor. This alkaline solution was then extracted with a further (4 X 250 parts by volume) of chloroform, before the two chloroform extracts were mixed, washed with water (2 X 300 parts by volume) and dried over an hydros magnesium sulphate. The chloroform was then filtered and removed by rotary evaporation to yield a mobile brown oil (45.1 parts; 82.6%) b.pt.: 138-142"C.

(ii) 3-Amino-s-triazolo-r4, 3-aJ-pyridin e 2-Pyridyl hydrazine (10.9 parts; 0.1 moles) was dissolved in A.R. methanol (50 parts by volume) at room temperature with stirring. Cyanogen bromide (10.6 parts; 0.1 moles) was dissolved in A.R. methanol (50 parts by volume) and added dropwise to the above solution over 30 minutes. The reaction was exothermic, the temperature rising to 55"C during the course of th6 addition. The reaction was then stirred and boiled for 4 hours, before the methanol was removed by rotary evaporation to give a pale yellow solid, which on recrystallisation from butanol yielded 12.6 parts (m.pt.: 245-7"C).

Preparation of 2-Amino-s-triazolo-[5, I -aJ-pyridine 3-Amino-s-triazolo-(4,3-a]-pyridine hydrobrornide (15 parts; 0.08 moles) was added portionwise to 50 parts by volume of 10% w/v caustic liquor at room temperature with stirring. The mixture was heated to boiling over 30 minutes and boiled under reflux for 48 hours with stirring. The reaction mixture was then cooled to room temperature and continuously extracted for 72 hours with chloroform (500 parts by volume). The chloroform was then removed by rotary evaporation and the solid produced was extracted with boiling toluene (100 parts by volume) to yield a grey solid (3.47 parts) m.pt.: 104"C.

Preparation of the Dye Base Diazo tisa tion The 3-Amino-s-triazolo-[4, 3-al-pyridine hydrobromide was dissolved in water (50 parts by volume) at room temperature with stirring. To this solution was added concentrated hydrochloric acrid (10 parts by volume) and the mixture cooled to below 10"C. 2N Sodium nitrite (12 parts by volume) was added in one lot below 10"C with stirring and the mixture allowed to stir for 1 5 minutes. Excess nitrous acid was then removed by the addition of 10% sulphamic acid to a 10 minute end point on starch iodide paper, before coupling.

Coupling The N-ethyl-N-benzyl aniline was dissolved in water (50 parts by volume) and concentrated hydrochloric acid (20 parts by volume) at room temperature with stirring. The diazo was added over 1 5 minutes with stirring and the temperature was allowed to rise gradually to 20"C during the addition. The excess acidity was removed by addition of sodium acetate crystals and the sticky oil extracted with chloroform. The chloroform was dried over anhydrous MgSO4 and the dyestuff separated on an Alumina '0' column. The chloroform extracts containing the dyestuff were removed by rotary evaporation.

Preparation of a cationic dyestuff The dyebase (3.6 parts; 0.01 moles) was dissolved in glacial acetic acid (50 parts by volume) and magnesium oxide 'light' grade (1.05 parts; 0.03 moles) added. The acid solution of dyebase was then raised to 50-60"C with stirring and dimethyl sulphate (8 parts; 0.05 moles) added dropwise. Quaternisation was then continued at elevated temperatures until complete or until such time when the formation of decomposition products suggested it to be beneficial to stop the reaction. Progress of the reaction was monitored by Thin Layer Chromatography (eluent, chloroform / methanol; 4:1).

After cooling, the reaction mixture was drowned into water (300 parts by volume), stirred with 'hyflo' Supercel (1 part) and screened through a layer of 'hyflo' Supercel to remove the inorganic salts. Finally, the dyestuff was isolated by adding 100% w/v aqueous zinc chloride solution (3 parts by volume) and salted to 10-20% w/v.

The dyestuff obtained had the constitution:

and dyed "Orlon"" acrylic fibre a bright violet shade, the dyed cloth exhibiting good fastness properties.

*Orlon is a Registered Trade Mark.

Claims (9)

1. An azo dyestuff having the formula T-N=N-E wherein T is the residue of a s-triazolo-(4,3-a]- or [5,1-a]-pyridine and E is the residue of a coupling component.

2. A water soluble azo dyestuff free of carboxylic acid and sulphonic acid groups which is a cationic derivative of the dyestuff of claim 1 and has the formula: [11 - N = N - wherein T1 is the residue of a quaternised s-triazolo-[4,3-a]- or (5,1-a]-pyridine, E has the meaning given in claim 1 and AG is an anion.

3. A dyestuff as claimed in claims 1 or 2 substantially as herein described with reference to the Example.

4. A process for the manufacture of the dyestuff claimed in claim 1 which comprises diazotising an amine TNH2 and reacting the diazonium compound so formed with a compound EH wherein T and E have the meanings given in claim 1.

5. A process for the manufacture of the dyestuff claimed in claim 2 which comprises quaternising the dyestuff claimed in claim 1.

6. A process as claimed in claims 4 or 5 substantially as herein described with reference to the Example.

7. A process for colouring textile material which comprises contacting the material with a dyestuff as claimed in claim 1.

8. A process for colouring paper or synthetic polymeric material which comprises contacting the paper or polymeric material with a dyestuff as claimed in claim 2.

9. Paper, synthetic polymeric and other textile materials whenever coloured by a dyestuff as claimed in claims 1 or 2.