WO2001010854A1

WO2001010854A1 - Benzothiazole compounds and their use as optical brighteners

Info

Publication number: WO2001010854A1
Application number: PCT/EP2000/007438
Authority: WO
Inventors: Victor Paul Eliu; Julia Hauser
Original assignee: Ciba Specialty Chemicals Holding Inc.
Priority date: 1999-08-09
Filing date: 2000-08-01
Publication date: 2001-02-15
Also published as: AU6279100A

Abstract

The invention relates to novel benzothiazole compounds of formula (1) wherein X represents hydrogen or SO3M; Y represents hydrogen, C1-C5-alkyl, C1-C5-alkyloxy or halogen and Z represents (a); (b); -CN or (c); a process for their preparation and use of the compounds as optical brightening agents for textiles, detergents and paper.

Description

BENZOTHIAZOLE COMPOUNDS AND THEIR USE AS OPTICAL

BRIGHTENERS

The present invention relates to new benzothiazole substituted styrene and stilbene compounds, a process for their preparation and use of the compounds as optical brightening agents.

Benzothiazolylstilbene compounds have been described in Swiss Patent Nr. 542266. However, the derivatives described herein are restricted to such carrying hydrophobic substituents and hence are of limited utility.

The novel benzothiazolyl substituted styrene and stilbene compounds are represented by the formula

wherein

X represents hydrogen or SO₃M;

Y represents hydrogen, d-C₅-alkyl, d-Cs-aikyloxy or halogen and

Z represents ; -CN or

Ri is hydrogen; Crdβ-alkyl oder C₂-C₁₈-alkenyl which is unsubstituted or substituted by cyano, halogen, SO₃M, -SH, CrCs-alkylthio, d-Cs-alkoxy, amino, C C₅monoalkylamino, Cι-C₅-dialkylamino or carboxy; mono-, di- or trihydroxy-d-Cs-alkyl;

a radical of formula -HO-(CH„) -OH , amino; CrCs-monoalkylamino; CrC₅- m. dialkylamino; phenyl or phenyl-C C₃-alkyl which is unsubstituted or substituted by one or more CrC₅- alkyl, CrC₅-alkoxy, hydroxy, carboxyl, cyano, sulfo or halogen; R₂ and R₃ independently represent hydrogen, C C ₅-alkyl which is unsubstituted or substituted by cyano, -SH, d-C₅-alkylthio, d-C₅-alkoxy or carboxy; hydroxy-C C₅- alkyi; mono- or di-d-Cs-alkylamino-d-Cs-alkyl; phenyl or phenyl-Cι-C₃-alkyl which is unsubstituted or substituted by one or more d-C₅-alkyl, CrC₅-alkoxy,hydroxy, cyano, SO₃M or carboxy, or

R and R₃, together with the nitrogen atom connecting them, form a 5- or 6- membered heterocyclic ring;

R₄ is hydrogen, d-C₅-alkyI, d-C₅-alkoxy,hydroxy, cyano, SO₃M or halogen;

M is hydrogen, an alkaline or alkaline earth metal cation or a cation formed from an amine; rrh is a number from 1 to 5; and

^ is a number from 1 to 3, with the proviso that when X represents hydrogen and Z the

residue , R₄ represents SO₃M.

Preferred compounds of formula (1 ) are those in which Y represents hydrogen or d-C ₅-alkyl;

Z represents ^or "⁽-^{;N ancl}

Ri is hydrogen; d-C₁₈-alkyl or C₂-C -alkenyl which is unsubstituted or substituted by by cyano, halogen, SO₃M, -SH, d-C₅-alkylthio, d-C₅-alkoxy, or hydroxy; phenyl which is unsubstituted or substituted by one or more d-C₅-alkyl, d-C₅-alkoxy, hydroxy, carboxyl, cyano, sulfo or halogen; R₂ and R₃ independently represent hydrogen, d-C ₅-alkyl which is unsubstituted or substituted by cyano, halogen, SO₃M, -SH, C C₅-alkylthio, d-C₅-alkoxy or hydroxy; phenyl or phenyl-Cι-C₃-alkyl which is unsubstituted or substituted by one or more C C₅-alkyl, d-C₅-alkoxy, hydroxy, cyano,

SO₃M or carboxy and M is Li, Na, K, Ca, Mg, ammonium, quaternary ammonium with d-C₈-alkyl groups, primary, secondary or tertiary ammonium with d-C₈-alkyl groups or mono-, di- or triethanolamino, of which those in which R^ R₂ and R₃ are, independently, hydrogen, Cι-C₅- alkyl or phenyl and M is K or Na are of particular interest. Further compounds of particular interest are those in which Z is

R₄ is hydrogen, d-C₅-alkyl, or SO3M and M is K or Na.

Especially interesting compounds are those of the formula

X

in which X, Y and Z being are as defined previously.

Of the compounds of formula (2) those in which X represents hydrogen or SO₃M,

Y represents hydrogen or methyl and Z represents

M being K or Na and R is hydrogen or SO₃M are most especially interesting as are compounds of formula (2) in which X represents hydrogen or SO₃ , Y represents hydrogen

or methyl and Z is a group of the formula \ h— o— R, ; V^~ N_χ ² or -CN, wherein

O O R₃

M is K or Na, R^ is d-C₄-alkyl and R₂ and R₃ are hydrogen or d-C₄-alkyl

When in compounds of formulae (1) or (2) C d₈-alkyl are straight chain or branched residues these may be methyl, ethyl, n-propyl, isopropyl, n-butyl, sec.butyl, tert.butyl, amyl, isoamyl or tert.amyl, hexyl. heptyl, octyl, isooctyl, nonyl, decyl, undecyl, dodecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl or octadecyl residues. d-C₅-Alkoxy or d-C₅-alkylthio may be straight chain or branched residues such as methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec.butoxy, tert.butoxy, amyloxy, isoamyloxy or tert. amyloxy or methylthio, ethylthio, n-propylthio, isopropylthio, n-butylthio, tert.butylthio or amylthio.

C₂-C₁₈-Alkenyl represent, for example, allyl, methallyl, isopropenyl, 2-butenyl, 3-butenyl, isobutenyl, n-penta-2,4-dienyl, 3-methylbut-2-enyl, n-oct-2-enyl, n-dodec-2-enyl, isododecenyl or n-octadec-4-enyl.

Examples of d-C₅-monoalkylamino or Cι-C₅-dialkylamino are methylamino, ethylamino, propylamino, butylamino, or pentylamino or dimethylamino, diethylamino, dipropylamino, dibutylamino or dipentylamino.

When the substituents R₂ and R₃ together with the nitrogen atom connecting them form a heterocyclic ring, this may be a pyrrolidine, piperidine, pipecoline, morpholine, thiomorpholine, piperazine, N-alkylpiperazine such as methyJpiperazine, N-phenylpiperazine or N-alkyiimidazoline ring. Preferred saturated heterocyclic residues are pyrrolidino, piperidino or morpholino.

Halogen may be chlorine, bromine or iodine, but is preferably chlorine.

When M represents an alkaline or alkaline earth metal these are preferably Li, K, Na, Ca or Mg, whilst when M represents a cation formed from an amine these may be NH₄, mono-, di-, tri- or tetramethylammonium, mono-, di-, tri- or tetraethylammonium, mono, di-, tri- or tetra-n- or isopropylammonium, mono, di-, tri- or tetra-n-, sec- or t-butyiammonium, mono-, di- or t ethanolammonium, mono-, di- or tri- n- or isopropanolammonium, mono-, di- or tri-n- sec- or t-butanolammonium, morpholinium, piperidinium or pyrrolidinium.

A further aspect of the present invention is a process for the preparation of a compound of formula (1) or (2) characterised by a) diazotisating an amine of formula

in strong mineral acid and in the presence of a diazotising reagent and b) subsequently reacting the resulting diazonium salt with a compound of formula

Z-CH=CH₂ (4)

in a solvent and in the presence of a catalyst and an inorganic salt, X, Y and Z being as previously defined.

The diazotisation step a) of the process is carried out in the presence of a strong mineral acid and a diazotising reagent. Suitable strong mineral acids are, for example, hydrochloric acid, sulphuric acid, methane sulphonic acid or tetrafluoroboric acid, sulphuric acid being particularly preferred, whilst suitable diazotising reagents are, for example, sodium nitrite, d-C₅-alkyl nitrites or nitrosyl sulphuric acid, sodium nitrite being especially suitable. The temperature at which the diazotisation reaction is carried out is dependent on the amine of formula (2), but , in general, lies within the range of between -10 and 30°C, -5 to 25°C or 0 to 25°C being preferred.

The palladium (II) compound used as a catalyst in step b) of the process is PdCI₂, PdBr₂, Pd(NO₃)₂, H₂PdCI₄, Pd(OOCCH₃)₂, [PdCI₄]Na₂, [PdCI₄]Li₂, [PdCI₄]K₂, palladium(ll)acetylacetonate, palladium(ll)dibenzylideneacetone (dba) or solvates thereof, dichloro-(1 ,5-cyclooctadiene)palladium(ll), dichlorobis-(acetonitrile)palladium(ll), dichlorobis- (benzonitrile)palladium(ll), π-allylpalladium(ll)chloride dimer, bis-(π-methallyl palladium(ll)chloride) or π-allylpalladium(ll)acetylacetonate, PdCI₂, Pd(dba)₂, or Pd(OCOCH₃)₂.or PdCI₂ being preferred.

The quantity of palladium catalyst used is in an amount of 0.01 to 5 mole %, based on the diazonium salt, preferrably 0.1 to 1%. Step b) of the process may be effected in water as solvent or may be conducted in a two- phase solvent system comprising water and a water-immiscible organic solvent such as halogenated hydrocarbons in the presence of a phase transfer catalyst. Alternatively, an organic solvent may be employed, whereby the organic solvent is one or more of an alcohol; ketone; carboxylic acid; sulfone; sulfoxide; N,N-tetrasubstituted urea; N-alkylated lactam or N-dialkylated acid amide; ether; aliphatic carboxylic acid ester or lactone; nitrile; and a glyme.

The inorganic salt used in step b) of the process is a Li-, Na-, K-, NH₄-, Mg- or Ca--salt of a carboxylic acid, preferably lithium-, potassium- or sodium acetate, bicarbonate or carbonate, whereby sodium or potassium acetate, or sodium or potassium bicarbonate are especially suitable, the inorganic salt being used in excess.

The reaction step b) of the process is carried out at a temperature of between 10 and 100°C, preferably at between 10 and 80°C and most preferably at between 20 and 70°C,

In dissolved or finely divided states, the brighteners defined the above process display a more or less pronounced fluorescence. They are therefore used, according to the invention, for optically brightening synthetic or natural organic materials.

Examples of such materials which may be mentioned, without the review given below being intended to express any limitation thereto, are textile fibres from the following groups of organic materials, insofar as optical brightening thereof enters into consideration:

(a) Polyamides which are obtainable as polymerisation products by ring opening, for example those of the polycaprolactam type,

(b) polyamides which are obtainable as polycondensation products based on bifunctional or polyfunctional compounds capable of undergoing a condensation reaction, such as hexamethylenediamine adipate and

(c) natural textile organic materials of animal or vegetable origin, for example based on cellulose or proteins, such as cotton or wool, linen or silk.

The organic materials to be optically brightened can be in diverse stages of processing and are preferably finished textile products. They can, for example be in the form of hank goods, textile filaments, yarns, twisted yarns, nonwovens, felts, textile fabrics, textile composites or knitted fabrics.

The brighteners defined above are of particular importance for the treatment of textile fabrics. The treatment of textile substrates is advantageously carried out in an aqueous medium in which the particular optical brighteners are present in a finely divided form (suspensions, so-called microdispersions and in some cases solutions). Dispersing agents, stabilisers, wetting agents and further auxiliaries can optionally be added during the treatment.

The treatment is usually carried out at temperatures of from about 20° to 140°C, for example at the boiling point of the bath, or in the region thereof (about 90°C). For the finishing, according to the invention, of textile substrates it is also possible to use solutions or emulsions in organic solvents, as are used in dyeing practice in so-called solvent dyeing (pad-thermofix method and the exhaustion dyeing process in dyeing machines).

The optical brighteners which can be used according to the present invention can also be employed, for example, in the following use forms:

(a) In mixtures with so-called "carriers", wetting agents, softeners, swelling agents, antioxidants, light stabilisers, heat stabilisers and chemical bleaching agents (chlorite bleach and bleaching bath additives).

(b) In mixtures with crosslinking agents and finishing agents (for example starch or synthetic finishing agents) and also in combination with very diverse textile finishing processes, especially synthetic resin finishes (for example crease resistant finishes such as "wash-and- wear", "permanent press" and "no-iron"), and also flame resistant finishes, soft handle finishes, anti-soiling finshes or anti-static finishes or antimicrobial finishes.

(c) As additives to various soaps and washing agents.

(d) In combination with other substances having an optical brightening action.

If the brightening process is combined with textile treatment or finishing methods, the combined treatment can in many cases advantageously be effected with the aid of corresponding stable formulations which contain the compounds having an optical brightening action in a concentration such that the desired brightening effect is obtained. In certain cases, the full effect of the brightener is achieved by an after-treatment. This can be, for example, a chemical treatment (for example acid treatment), a thermal treatment (for example heat) or a combined chemical/heat treatment.

The amount of the optical brighteners to be used according to the invention, relative to the material to be optically brightened, can vary within wide limits. A distinct and durable effect can already be achieved with vary small amounts and in certain cases, for example, with amounts of 0.03% by weight. However amounts of up to about 0.5% by weight can also be used. For most cases of interest in practice, amounts of between 0.05 and 0.5% by weight relative to the material to be brightened, are preferably of interest.

The optical brighteners are also especially suitable as additives for washing baths or to industrial and household washing agents and they can be added in various ways. They are appropriately added to washing baths in the form of their solutions in water or organic solvents or also in a state of fine division as aqueous dispersions or slurries. They, or their components, are advantageously added to household or industrial washing agents at any phase of the manufacturing process of the washing agent, for example to the so-called "slurry" prior to spray-drying of the washing powder or during the preparation of liquid washing agent combinations. The compounds can be added both in the form of a solution or dispersion in water or other solvents and also without auxiliaries in the form of a dry brightener powder. However, they can also be sprayed, in the dissolved or pre-dispersed form, onto the finished washing agent.

Washing agents which can be used are the known mixtures of detergent substances, such as, for example, soap in the form of chips and powders, synthetic products, soluble salts of sulphonic acid half-esters of higher fatty alcohols, arylsulphonic acids, which are substituted by higher alkyl and /or polysubstituted by alkyl, carboxylic acid esters with alcohols of medium to higher molecular weight, fatty acid acylaminoalkyl- or aminoaryl-glycerol- sulphonates, phosphoric acid esters of fatty alcohols and the like. So-called "builders" which can be used are, for example, alkali metal polyphosphates and alkali metal polymeta- phosphates, alkali metal pyrophosphates, alkali metal salts of carboxyethylcellulose and other "soil redeposition inhibitors", and also alkali metal silicates, alkali metal carbonates, alkali metal borates, alkali metal perborates, nitrilotriacetic acid, ethylenediamine-tetraacetic acid and foam stabilisers, such as alkanolamides of higher fatty acids. Furthermore, the washing agents can contain, for example: antistatic agents, superfatting skin protection agents, such as lanolin, enzymes, antimicrobial agents, perfumes and dyestuffs.

The brighteners have the particular advantage that they are also effective in the presence of active chlorine donors, such as, for example, hypochlorite and can be used without substantial loss of the effects in washing baths with non-ionic washing agents, for example alkylphenol polyglycol ethers. Also in the presence of perborate or peracids and activators, for example tetraacetylglycoluril or ethylenediamine-tetraacetic acid are the new brighteners very stable both in pulverulent washing agent and in washing baths.

The brighteners according to the invention are added in amounts of 0.005 to 2% or more and preferably of 0.03 to 0.5%, relative to the weight of the liquid or pulverulent ready-to-use washing agent. When they are used to wash textiles made of cellulose fibres, polyamide fibres, cellulose fibres with a high grade finish, wool and the like, wash liquors which contain the indicated amounts of the optical brighteners according to the invention impart a brilliant appearance in daylight.

The washing treatment is carried out, for example, as follows:

The indicated textiles are treated for 1 to 30 minutes at 5° to 100°C and preferably at 25° to 100°C in a wash bath which contains 1 to 10 g/kg of a composite washing agent containing builders and 0.05 to 1 % relative to the weight of the washing agent, of the brighteners claimed. The liquor ratio can be 1 :3 to 1 :50. After washing, the textiles are rinsed and dried in the customary manner. The wash bath can contain, as a bleach additive, 0.2 g/l of active chlorine (for example in the form of hypochlorite) or 0.1 to 2 g/l of sodium perborate.

The brighteners according to the invention can also be applied from a rinsing bath with a "carrier". For this purpose the brightener is incorporated in a soft rinsing agent or in another rinsing agent, which contains, as the "carrier", for example, polyvinyl alcohol, starch, copolymers on an acrylic basis or formaldehyde/urea or ethylene-urea or propylene-urea derivatives, in amounts of 0.005 to 5% or more and preferably of 0.2 to 2%, relative to the rinsing agent. When used in amounts of 1 to 100 ml, and preferably of 2 to 25 ml, per litre of rinsing bath, rinsing agents of this type, which contain the brighteners according to the invention, impart brilliant brightening effects to very diverse types of treated textiles. A further application of the compounds of the invention is for the brightening of paper, either in the pulp mass during paper manufacture or in the size-press, which has been described in British Patent Specification 1 ,247,934, or preferably in coating compositions. When brighteners of the present invention are employed in such formulations papers brightened with them exhibit a very high degree of whiteness.

Furthermore, the compounds of the invention are useful for the mass whitening of synthetic fibres and plastics as described in "Fluorescent Whitening Agents", R.Anliker and G.Mϋller, Georg Thieme Publishers Stuttgart, 1975, pages 65-82.

The compounds obtained by the process of the present invention are particularly advantageous in that they exhibit not only extremely high whitening ability, but, in addition, in many cases highly desirable water solubilities and also possess excellent white aspects in the solid state.

The following Examples serve to illustrate the invention; parts and percentages are by weight, unless otherwise stated.

Example 1

S0₃Na

A 500ml. 4-necked flask equipped with stirrer and heating/cooling bath is charged with 200ml. of water and 33g of 4-(6-methylbenzothiazol-2-yl-7-sulphonic acid)benzeneamine are stirred in. 12g. of 37% aqueous sodium hydroxide solution are added dropwise, raising the pH to 7-8, and the temperature raised to 65°C, resulting in a homogenous solution. The solution is cooled to 10-20°C by the addition of 120g. of ice and 17g. of a 36% solution of sodium nitrite in water added. 34.5g. of concentrated hydrochloric acid are then added dropwise over 20 minutes, the temperature being maintained at between 10 and 20°C. After stirring for a further 30 minutes the nitrite excess is neutralised with sulphamic acid and the suspension filtered, washed with water and sucked dry.

The filter-cake is suspended in 300ml. of n-pentanol and 10g. of acetic anhydride added dropwise with cooling below 20°C. After stirring for a further 20 minutes, 18.5g. of sodium hydrogen carbonate are slowly added, the foam formation being maintained under control. Then 0.3g of palladium dibenzylacetone and 20g. of styrene are added with stirring. Reaction commences immediately with vigorous gas evolution. The temperature rises to 60°C within approximately 8 hours after which time no remaining diazonium salt can be detected. The mixture is filtered, the filter-cake dried under vacuum and then recrystallized from methanol/water to yield 28g. of the compound of formula (5).

¹H-NMR Spectrum in DMSO-D₆:

8.12 (d, 2H, aromatic, j = 8 Hz) 7.88 (d, 1 H, aromatic, j = 8 Hz) 7.80 (d, 2H, aromatic, j = 8 Hz) 7.65 (d, 2H, aromatic, j = 8 Hz) 7.40 (d, 1 H, aromatic, j = 8 Hz) 7.40 (t, 2H, aromatic, j = 8 Hz) 7.40 (d, 1 H, aromatic, j = 8 Hz) 7.40 (q, 2H, vinylic, j = 16 Hz) 2.75(s, 3H, aliphatic).

Example 2

A 500ml. 4-necked flask equipped with stirrer and heating/cooling bath is charged with 200ml. of water and 33g of 4-(6-methylbenzothiazol-2-yl-7-sulphonic acid)benzeneamine are stirred in 12g of 37% aqueous sodium hydroxide solution are added dropwise, raising the pH to 7-8, and the temperature raised to 65°C, resulting in a homogenous solution The solution is cooleα to 10-20°C by the addition of 120g. of ice and 17g of a 36% solution of sodium nitrite in water added. 3^ 5g. of concentrated hydrochloric acid are then added dropwise over 20 minutes, the temperature being maintained at between 10 and 20°C After stirring for a further 30 minutes the nitrite excess is neutralised with sulphamic acid and the suspension filtered, washed with water and sucked dry.

The filter-cake is suspended in 300ml. of glacial acetic acid and 40g. of acetic anhydride added dropwise with cooling below 20°C. After stirring for a further 20 minutes, 16.5g. of sodium hydrogen carbonate are slowly added, the foam formation being maintained under control. Then 0.3g of palladium dibenzylacetone and 26g. of styrene-3-sulphonιc acid are added with stirring Reaction commences immediately with vigorous gas evolution. The temperature rises to 60°C within approximately 8 hours after which time no remaining diazonium salt can be detected. The mixture is filtered, the filter-cake dried under vacuum and then recrystallized from water and sodium chloride to yield 50g. of the compound of formula (6).

¹H-NMR Spectrum in DMSO-D₆-

8 10 (d, 2H, aromatic, j = 8 Hz)

7.92 (s, 1 H, aromatic, adjacent to the sulphonic acid group)

7.90 (d, 1 H, aromatic, j = 8 Hz)

7.80 (d, 2H, aromatic, j = 8 Hz)

7.60 (d, 1 H, aromatic, j = 8 Hz)

7.55 (d, 1 H, aromatic, j = 8 Hz)

7.40 (t, 1 H, aromatic, j = 8 Hz)

7 40 (d, 1 H, aromatic, j = 8 Hz)

7 40 (q, 2H, vinylic, j = 16 Hz)

2 73(s, 3H, aliphatic) Example 3

S0₃Na

The filter-cake is suspended in 300ml. of glacial acetic acid and 40g. of acetic anhydride added dropwise with cooling below 20°C. After stirring for a further 20 minutes, 16.5g. of sodium hydrogen carbonate are slowly added, the foam formation being maintained under control. Then 0.3g of palladium dibenzylacetone and 21 g. of styrene-4-sulphonic acid are added with stirring. Reaction commences immediately with vigorous gas evolution. The temperature rises to 50°C within approximately 8 hours after which time no remaining diazonium salt can be detected. The mixture is filtered, the filter-cake dried under vacuum and then recrystallized from water and sodium chloride to yield 50g. of the compound of formula (7).

¹H-NMR Spectrum in DMSO-D₆:

8.10 (d, 2H, aromatic, j = 8 Hz) 7.90 (d, 1 H, aromatic, j = 8 Hz) 7.80 (d, 2H, aromatic, j = 8 Hz) 7.65 (s, 4H, aromatic) 7.40 (d, 1 H, aromatic, j = 8 Hz) 7.40 (q, 2H, vinylic, j = 16 Hz) 2.705(ε_. 3H, aliphatic).

Example 4

A 500ml. 4-necked flask equipped with stirrer and heating/cooling bath is charged with 120ml. of glacial acetic acid and 19.2g of 4-(6-methylbenzothiazol-2-yl)benzeneamine are stirred in. 35.5g. of 50% tetrafluoroboric acid are added dropwise. The well-stirred pale slurry is cooled to 15°C and 16g. of a 36% solution of sodium nitrite in water added dropwise over 30 minutes, the temperature being maintained below 20°C. After stirring for a further 60 minutes at this temperature the nitrite excess is neutralised with sulphamic acid. 160g. of acetic anhydride are then added dropwise with cooling below 20°C. After stirring for a further 20 minutes, 16.8g. of sodium hydrogen carbonate are slowly added, the foam formation being maintained under control. Then 0.3g of palladium dibenzylacetone and 9.0g. of ethyl acrylate are added with stirring. Reaction commences immediately with vigorous gas evolution. The temperature rises to 30°C within 2 to 3 hours. Stirring is continued for a further 5 hours, after which time no remaining diazonium salt can be detected. The mixture is filtered to remove salts formed during the reaction and the acetic acid filtrate diluted with 500ml. of water. The precipitated product is filtered and dried under vacuum to yield 50g. of the compound of formula (8).

¹H-NMR Spectrum in DMSO-D₆:

8.12 (d, 2H, aromatic, j = 8 Hz) 7.95 (d, 1 + 1 H, aromatic, j = 8 Hz) 7.90 (d, 2H, aromatic, j = 8 Hz) 7.75 (d, 1 H, vinylic, j = 16 Hz) 7.45 (d, 1 H, aromatic, j = 8 Hz) 6.77 (d, 1 H, vinylic. j = 16 Hz) 4.25 (q, 2H, aliphatic ester) 2.50 (s, 3H, aliphatic) 1.30 (t, 3H, aliphatic ester).

Example 5

A 500ml. 4-necked flask equipped with stirrer and heating/cooling bath is charged with 120ml. of glacial acetic acid and 19.2g of 4-(6-methylbenzothiazol-2-yl)benzeneamine are stirred in. 19.2g. of methanesulphonic acid are added dropwise. The well-stirred pale slurry is cooled to 15°C and 16g. of a 36% solution of sodium nitrite in water added dropwise over 30 minutes, the temperature being maintained below 20°C. After stirring for a further 60 minutes at this temperature the nitrite excess is neutralised with sulphamic acid. 60g. of acetic anhydride are then added dropwise with cooling below 20°C. After stirring for a further 20 minutes, 16.8g. of sodium hydrogen carbonate are slowly added, the foam formation being maintained under control. Then 0.3g of palladium dibenzyiacetone and 7.0g. of acrylamide are added with stirring. Reaction commences immediately with vigorous gas evolution. The temperature rises to 30°C within 2 to 3 hours. The temperature is raised to 70oC and stirring is continued for a further 5 hours, after which time no remaining diazonium salt can be detected. The mixture is filtered to remove salts formed during the reaction and the acetic acid filtrate diluted with 500ml. of water. The precipitated product is filtered and dried under vacuum to yield 15g. of the compound of formula (9).

¹H-NMR Spectrum in DMSO-D₆:

8.10 (d, 2H, aromatic, j = 8 Hz) 7.90 (d, 2H, aromatic, j = 8 Hz) 7.70 (d, 2H, aromatic, j = 8 Hz) 7.50 (d, 1 H, vinylic, j = 16 Hz)

7.40 (d, 1 H, aromatic, j = 8 Hz) 6.75 (d, 1 H, vinyiic, j = 16 Hz) 2.45 (s, 3H, aliphatic).

Example 6

A 500ml. 4-necked flask equipped with stirrer and heating/cooling bath is charged with 120ml. of glacial acetic acid and 19.2g of 4-(6-methylbenzothiazol-2-yl)benzeneamine are stirred in. 9.2g. of methanesulphonic acid are added dropwise. The well-stirred pale slurry is cooled to 15°C and 16g. of a 36% solution of sodium nitrite in water added dropwise over 30 minutes, the temperature being maintained below 20°C. After stirring for a further 60 minutes at this temperature the nitrite excess is neutralised with sulphamic acid. 60g. of acetic anhydride are then added dropwise with cooling below 20°C. After stirring for a further 20 minutes, 16.8g. of sodium hydrogen carbonate are slowly added, the foam formation being maintained under control. Then 0.3g of a 20% solution of palladium chloride and 12.0g. of styrene-4sulphonic acid are added with stirring. Reaction commences immediately with vigorous gas evolution. The temperature rises to 40°C within 2 to 3 hours. The temperature is raised to 70°C and stirring is continued for a further 5 hours, after which time no remaining diazonium salt can be detected. The mixture is filtered, the filter-cake dried in vacuum and the product recrystallised from methanol/water to yield 28g. of the compound of formula (10).

¹H-NMR Spectrum in DMSO-D₆:

8.10 (d, 2H, aromatic, j = 8 Hz) 7.90 (d, 1 H, aromatic, j = 8 Hz) 7.80 (d, 2H, aromatic, j = 8 Hz) 7.65 (s, 4H, aromatic) 7.40 (d, 1 H, aromatic, j = 8 Hz) 7.40 (q, 2H, vinylic, j = 16 Hz) 2.75 (s, 3H, aliphatic).

Example 7

S0₃Na

A 500ml. 4-necked flask equipped with stirrer and heating/cooling bath is charged with 120ml. of glacial acetic acid and 33g of 4-(6-methylbenzothiazol-5-sulphonic acid-2- yl)benzeneamine are stirred in. 12g. of 37% aqueous sodium hydroxide solution are then added dropwise to pH 7-8 and the temperature raised to 65°C, when a homogenous solution results. The solution is cooled to 10 to 20°C by the addition of 120g. of ice and 17g. of a 36% solution of sodium nitrite in water added dropwise over 30 minutes. 34.5g. of concentrated hydrochloric acid are then added dropwise over 30 minutes, the temperature being maintained between 10 and 20°C. After stirring for a further 30 minutes at this temperature the nitrite excess is neutralised with sulphamic acid, the suspension filtered, washed with water and sucked dry.

The filter-cake is suspended in 300ml. of glacial acetic acid and 40g. of acetic anhydride are then added dropwise with cooling below 20°C. After stirring for a further 20 minutes, 16.5g. of sodium hydrogen carbonate are slowly added, the foam formation being maintained under control. Then 0.3g of palladium dibenzyiacetone and 14g. of n-butyl acrylate are added with stirring. Reaction commences immediately with vigorous gas evolution. The temperature rises to 50°C within approximately 8 hours, after which time no remaining diazonium salt can be detected. The mixture is filtered, the filter-cake suspended in 500ml. of water and neutralised with sodium hydroxide solution. The precipitated product is filtered and dried under vacuum to yield 38g. of the compound of formula (10). ¹H-NMR Spectrum in DMSO-D₆:

8.12 (d, 2H, aromatic, j = 8 Hz) 7.95 (d, 1 H, aromatic, j = 8 Hz) 7.95 (d, 2H, aromatic, j = 8 Hz) 7.75 (d, 1 H, vinylic, j = 16 Hz) 7.40 (d, 1 H, aromatic, j = 8 Hz) 6.85 (d, 1 H, vinylic, j = 16 Hz) 4.20 (t, 2H, aliphatic). 2.75 (s, 3H, aliphatic) 2.05 (m, 2H, aliphatic) 1.75 (m, 2H, aliphatic) 1.25 (t, 3H, aliphatic).

Example 8

A hand-sheet former is used to prepare paper samples (surface weight 160g/m²) from a mixture of birch/pine (1 :1 ) sulphate cellulose with a degree of grinding of 35°SR, 10% calcium carbonate being used as filler and 0.03% of a polymeric cationic polyacrylic acid ester (Percol 292) as retention agent.

The compounds listed in Table 1 are dissolved in deionised water and added to the pulp at a concentration of 2.2%. The subsequent exhaustion time is 15 minutes, the retention agent being added shortly before paper forming and the paper samples are then dried under vacuum at 80°C (Rapid Koethen System).

In a Spektroflasch 500 the brightness (ISO) is measured and the difference in brightness of the samples with and without optical brightening agent is calculated.

The results are listed as fluoresence values (ISO) in the following Table 1 : Table 1

Claims

1 . A benzothiazoie compound of the formula

wherein

X represents hydrogen or S0₃M;

Y represents hydrogen, d-C₅-alkyl, d-C₅-alkyloxy or halogen and

Z represents

Ri is hydrogen; d-dβ-alkyl oder C₂-C₁₈-alkenyl which is unsubstituted or substituted by cyano, halogen, SO₃M, -SH, Cι-C₅-alkylthio, C C₅-alkoxy, amino, d-C₅-mono- alkylamino, Ci-Cs- dialkylamino or carboxy; mono-, di- or trihydroxy-d-C₅-alkyl; a radical of formula

- -0-(CH,)- -OH , amino; d-C₅-monoalkylamino; Cι-C₅-dialkyiamino; phenyl m. or phenyl-C C₃-alkyl which is unsubstituted or substituted by one or more Cι-C₅- alkyl, Cι-C₅-alkoxy, hydroxy, carboxyl, cyano, sulfo or halogen; R₂ and R₃ independently represent hydrogen, C C ₅-alkyl which is unsubstituted or substituted by cyano, -SH, d-C₅-alkylthio, C_rC₅-alkoxy or carboxy; hydroxy-d-C₅- alkyl; mono- or di-Ci-Cs-alkylamino-CrCs-alkyl; phenyl or phenyl-Cι-C₃-alkyl which is unsubstituted or substituted by one or more d-C₅-alkyl, d-C₅-alkoxy,hydroxy, cyano,

SO₃M or carboxy, or R₂ and R₃, together with the nitrogen atom connecting them, form a 5- or 6- membered heterocyclic ring; R₄ is hydrogen, C C₅-alkyl, C C₅-alkoxy, hydroxy, cyano, SO₃M or halogen; M is hydrogen, an alkaline or alkaline earth metal cation or a cation formed from an amine; m, is a number from 1 to 5; and ni is a number from 1 to 3, with the proviso that when X represents hydrogen and Z the

residue , R represents S0₃M.

2. A compound according to claim 1 wherein Y represents hydrogen or Ci-C ₅-alkyl;

.R ',2

Z represents — o— R ', / ^N _N ^or "CN and

O O R.

Ri is hydrogen; C Cι₈-alkyl or C₂-C₄-alkenyl which is unsubstituted or substituted by by cyano, halogen, SO₃M, -SH, d-C₅-alkylthio, d-C₅-alkoxy, or hydroxy; phenyl which is unsubstituted or substituted by one or more d-C₅-alkyl, d-C₅-alkoxy, hydroxy, carboxyl, cyano, sulfo or halogen; R₂ and R₃ independently represent hydrogen, C_rC ₅-alkyl which is unsubstituted or substituted by cyano, halogen, SO₃M, -SH, Cι-C₅-alkylthio, Cι-C₅-alkoxy or hydroxy; phenyl or phenyl-d-C₃-alkyl which is unsubstituted or substituted by one or more d-C₅-alkyl, d-C₅-alkoxy,hydroxy, cyano,

S0₃M or carboxy and M is Li, Na, K, Ca, Mg, ammonium, quaternary ammonium with d-C₈-alkyl groups, primary, secondary or tertiary ammonium with C C₈-alkyl groups or mono-, di- or triethanolamino.

3. A compound according to claims 1 or 2 in which

Ri, R₂ and R₃ are, independently, hydrogen, Cι-C₅-alkyl or phenyl and M is K or Na.

4. A compound according to claim 1 in which

R₄ is hydrogen, d-C₅-alkyl, or SO₃M and M is K or Na.

5. A compound according to any one of claims 1 to 4 of the formula

X, Y and Z being as defined in claim 1.

6. A compound according to claim 5 in which X represents hydrogen or SO₃M, Y represents hydrogen or methyl and

Z represents

M being K or Na and R₄ is hydrogen or SO₃M.

7. A compound according to claim 5 in which X represents hydrogen or SO₃M, Y represents hydrogen or methyl and

Z is a group of the formula ^or "C , wherein

M is K or Na,

R_t is Cι-C₄-alkyl and

R₂ and R₃ are hydrogen or Cι-C₄-alkyl

8. A process for the preparation of a compound of formula (1) characterised by a) diazotisating an amine of formula

Z-CH=CH₂ (4)

in a solvent and in the presence of a catalyst and an inorganic salt, X, Y and Z being as defined in claim 1.

9. A process according to claim 5 in which the strong mineral acid is hydrochloric acid, sulphuric acid, methane sulphonic acid or tetrafluoroboric acid and the diazotising reagent is sodium nitrite, a d-C₅-alkyl nitrite or nitrosyl sulphuric acid.

10. A process according claims 5 or 6 in which the catalyst used in step b) is PdCI₂, PdBr₂, Pd(NO₃)₂, H₂PdCI₄, Pd(OOCCH₃)₂, [PdCI₄]Na₂, [PdCI₄]Li₂, [PdCI₄]K₂, palladium(ll)acetylacetonate, palladium(ll)dibenzylideneacetone (dba) or solvates thereof, dichloro-(1 ,5-cyclooctadiene)palladium(ll), dichlorobis-(acetonitrile)palladium(ll), dichlorobis- (benzonitrile)palladium(ll), π-allylpalladium(ll)chloride dimer, bis-(π-methallyl palladium(ll)chloride) or π-allylpalladium(ll)acetylacetonate.

11. A process according to any of claims 8 to 10 in which step b) is carried out in aqueous or non-aqueous solvent systems or mixtures thereof.

12. A process according to any one of claims 8 to 11 in which the inorganic salt is a Li-, Na-, K-, NH₄-, Mg- or Ca-salt of a carboxylic acid.

13. Use of the compounds of formula (1) as optical brightening agents for synthetic or natural organic materials. - 24 -

14. Use of the compounds of formula (1 ) according to claim 18 as optical brightening agents for paper in pulp, size-press or coating applications.

15. Use of the compounds of formula (1 ) according to claim 18 as optical brightening agents for textile materials, especially cotton and polyamide materials as well as mixtures of the same and other synthetic fibres.

16. Use of the compounds of formula (1 ) according to claim 18 as optical brightening agents in detergent compositions.