GB2216124A

GB2216124A - N4-substituted 1-methoxy-2 4-diaminobenzenes

Info

Publication number: GB2216124A
Application number: GB8904441A
Authority: GB
Inventors: R Mustafa Akram
Original assignee: Hans Schwarzkopf and Henkel GmbH
Current assignee: Hans Schwarzkopf and Henkel GmbH
Priority date: 1986-12-24
Filing date: 1989-02-27
Publication date: 1989-10-04
Anticipated expiration: 2009-02-27
Also published as: JPH023634A; DE3644980A1; DE3644980C2; DE3844517A1; FR2629454A1; FR2629454B1; CH677663A5; DE3806237C1; GB8904441D0; JPH0662520B2; GB2216124B

Description

"'216124 N 4 -Substituted 1-Methoxy-2,4-Diaminobenzenes This invention

relates to a process for the preparation of N 4 - substituted 1-methoxy-2,4-diaminobenzenes, selected compounds thereof, intermediates and aqueous dyeing compositions for keratin fibres.

The so-called oxidation dyes are particularly important for tinting hair and these are formed by oxidative coupling of developing components (such as, for example, p-phenylenediamines, p-aminophenols, p-diaminopyridines, etc.) with coupling components (such as, for example, phenols, resorcinols, m-aminophenols, mphenylenediamines, naphthols, pyrazolones, etc.). The dyes even when used under extreme application conditions (for example low dyeing temperature and short dyeing time) have deep shades and very good fastness properties.

Oxidation dyes also play an important role in pelt dyeing.

Good oxidation dye precursors should primarily meet the following application requirements; in the oxidative coupling with the particular coupling or developing components, they should produce the desired colour, which should have good exhaustion and levelling properties for hair or pelt, in sufficient intensity. The dyes formed should in general be stable and specifically washf ast,, lightfast, perspiration fast and heatresistant. In particular, under wearing conditions they shouldnot be susceptible to colour shifts of the original shade.

Moreover,, they should be toxicologically and dermatologically safe.

These requirements cannot always be reconciled.

This is Particularly evident for the so-called blue coupling agents. At present 2,4-idiaminoanisol, is a blue coupling agent which, on the one hand, is almost completely satisfactory in terms of practical application but on the other is questionable in terms of toxicology.

Also the compound 2 -amino- 4- (B-hydroxyethyl amino) - anisole as coupling agent is mentioned in German Offen legungsschrift 31132,,885 and in German Offenlegungs schrift 2,951,377.

We have now found it possible to provide an industrially advanced process for the preparation of known and novel compounds as blue coupling agents which a) are completely satisfactory as dyes, b) are toxico i 15 logically safe and c) are similarly economical as 2,4 diaminoanisole and its derivatives.

Blue coupling agents which meet these require ments are the compounds of general formula I and their salts with inorganic or e3roanic acids, the eco nomical-preparation of which compounds from commercially available starting materials has hitherto been unknown.

The preparation of the compounds of the general

Claims

formula I is described in Claim 1. Details of the preferred process

according to the invention are described below.

In step a, 4-methoxy-3-nitroacetanilide is deacylated by methods known per se by heating to about 60 to 95'C with a strong inorganic acid (for example hydro chloric acid, sulphuric acid or phosphoric acid) in aqueous medium over a period of about 3 to 8 hours (cf.

Beilsteins Handbuch der organischen Chemie (Beilatein's Handbook of Organic Chemistry), Springer Verlag, Vol. 13, supplement III, page 1201). Surprisingly, it has been found that the addition of about 10 to 151 by weight of a water-dilutable, organic, inert solvent, for example methanoi, dimethoxyethane, ethanol, to the reaction mixture,, which has previously been described as being present in a purely aqueous medium, causes an additional purification of the deacylated product of the formula III without incurring more expense or a loss in yield. After 3 the reaction has finished, the batch is neutralized with an inorganic base, for example sodium hydroxide solution, and, after the batch has cooled to about 5 to 10Cl the reaction product of the formula III separates and can be isolated by filtration or centrifugation. It is washed with water and dried in a customary manner.

The reaction of the compound of the formula III with a chloroalkyl chloroformate of the general formula IV is carried out by following the known selective hydroxyalkylation of an amine with chloroalkyl chloroformate followed by treatment of the chloroalkyl caxbamates with a base, cf. Otto, J. Prakt. Chem.. 2, 44, page 15 (1890). R. Adams and J.B. Segur J. Am. Chem. Soc. 45, p. 785 (1923) and J.S. Pierce and R. Adams J. Am. Chem. Soc. 45, p. 790 (1923) describe in detail the reaction of chloroalkyl chloroformates with primary aromatic amines. The compounds of the general formula V are formed by initially introducing the compound of the formula II in an inert organic solvent, such as,, for example, dioxane, dimethoxyethane, Cj- to C4-alcohols, dimethylformamide, tetrahydrofuran, toluene, chlorobenzene, methyl ethyl ketone, ethylene glycol dimethyl ether or diethylene glycol dimethyl ether and heating the mixture to a temperature between room temperature and reflux temperature, preferably between 70'C and reflux temperature. An equimolar amount or a small excess of the chloroalkyl chloroformate of the general formula IV is then metered in. If desired, the solvents can be combined with water. An acid-binding agent can either be initially introduced or can be added parallel to the already mentioned chloroalkyl chloroformate. Suitable acidbinding agents are bases such as alkali metal hydroxides, alkali metal bicarbonates, alkali metal carbonates, alkaline earth metal oxides, alkaline earth metal hydroxides, alkaline earth metal bicarbonates and alkaline earth metal carbonates and also tertiary organic amines. The reaction time is about 4 to 12 hours.

After the reaction is complete, the carbamates are isolated by a) adding water and stirring the batch in 4 the cold or b) f iltering off the inorganic salts and evaporating some or all of the solvent, during the course of which it may be necessary to cool. for example by the addition of ice, resulting in the almost quantitative precipitation of the carbamates formed of the general formula V in solid form.

The treatment with strong bases - suitable ones are alkali metal hydroxides or alkaline earth metal hydroxides, preferably 10 to 50% strength aqueous sodium hydroxide or potassium hydroxide solution is used converts the carbamates of the general formula V to the hydroxyalkyl compounds of the formula V1.

Two procedures are suitable for this purpose:

a) The carbamate of the formula V is initially introduced in water or an organic solvent, such as, for example,, a (Cl-CJ alcohol, a water-miscible ether or mixtures thereof, approximately the calculated amount of base, that is 3 mol of base per mole of carbamate is metered in at room temperature, and the mixture is stirred until the reaction is completed, It being pos sible to heat the mixture to reflux, if necessary.

b) The base. which can be diluted with the solvents mentioned, is initially introduced, the carbamate of the general formula V is metered in in pure form or dissolved in one of the organic solvents mentioned at a temperature between room temperature and about 700C, and the mixture is stirred until the reaction is completed. in both variants the reaction solution, which has a pH of about 12-14, can be buffered by the addition of an organic or inorganic acid to a pH of about 7 to about 10 for the purpose of workup. The inorganic salts are then separated off,' water may be added and the product of the general formula VI is isolated after removal of the organic solvent.

In both of the above procedures. addition of about 25 to 30% by weight of one of the abovementioned organic solvents to the aqueous reaction batch significantly shortens the reaction time, and the inorganic salts zemain dissolved in the reaction medium. The reaction requires about 4 to 12 hours.

The preparation of the compounds of the general formula I can be carried out by reduction of the compounds of the general formula VI with base metals or by catalytic reduction.

Customary catalysts, such as, for example, Raney nickel, palladium on charcoal, platinumcm charcoal may be used for the catalytic reduction. The reaction temperature is between room temperature and 120'C, preferably between 400 and 100'C, and the pressure is between atmospheric pressure and 100 bar, preferably between 20 and 70 bar. Suitable solvents are the customary solvents, such as, for example, water, toluene, glacial acetic acid, Iower.alcohols and ether compound5. After - the reduction is finished and the catalyst has been separated off, the product of the general formula I can be isolated in free form by evaporation of the solvent under an inert gas, but preferably it is - likewise under an inert gas converted by the addition of an approximately equivalent amount of an acid into a salt, which either precipitates directly or is obtained after removal of the solvent.

Examples of inorganic acids which are suitable for the salt formation are hydrochloric acid, sulphuric acid, phosphoric acid and organic acids are acetic acid, propionic acid, lactic acid or citric acid.

Preferred embodiments of the preparation process will now-be described with reference to the following non-limiting examples.

Example 1 Preparationof I -mathoxy-2 -amino- 4 - (13-hydroxyethyl amino) ben2ene sulphate A. Preparation of 1-methoxy-2-nitro-4-aminobenzene:

A mixture of 630.5 g (3 mol) of 1-methoxy-2nitro-4-acetylaminobenzene, 1500 ml of water and 300 ml of ethanol is heated to 80'C, and 1062 g of concentrated hydrochloric acid are added. Stirring at Wt. is continued for another 3 1/2 hours, the mixture is then cooled to 75C and the pH is brought to 7.0 with sodium hydroxide solution. After cooling the batch to about 10OCt the product is filtered off with suction, washed with water 6 and dried.

Yield..-475.5 g (94% of the theoretical value) Melting point: 54-55t B. Preparation of B-chloroethyl-N-(3-nitro-4-methoxyphenyl) carbamate:

420.5 g (2.5 mol) of the 1-methoxy-2-nitro-4aminobenzene prepared above in A are initially introduced Vith 135 g of calcium carbonate in 1275 rnl of monoethylene glycol dimethyl ether and 150 ml of water, and the mixture is heated to 7CC. 375 g of 13-chloroethyl chloroformate are added dropwise to this mixture over a period of 3 hours at such a rate that the reaction mixture is gently refluxed with the evolution of carbon dioxide. The mixture is refluxed for another 1 112 hours with stirring until the reaction is complete, cooled to 35'Cl and water and ice are added. The precipitated product is filtered off with suction, washed with water and dried.

Yield: 663 g (96.5% of the theoretical value) Melting point: 83-SCC IR Spectrum: see Figure 1 H- spectrum: (CDC13) 5 = 3.6-3.8 (t, 2Hr CH2-0); 8 3.9 (s, 3Hi O-CH3); 5 = 4.3-4.5 (t, 2H, CH2-Cl); s = 63-7.5 (rat 3H, Ar-H) ppm C. Preparation of 1-methoxy-2-nitro-4-(B-hycLroxyethylamino)benzene:

618 g (2.25 mol) of the D-chloroethyl N-(3-nitro4-methoxyphenyl) carbamate obtained above in 13. are Initially introduced in 2025 ml of water and 675 ml of ethanol. The reaction mixture is heated to 60"C, and 766 g of 50% strength potassium hydroxide solution are added dropwise over a period of 1 112 hours. Stirring at WC is continued f or 2 112 hours, the pH Of the batch is brought to 8 - 0 with glacial acetic acid, and the reaction mixture is slowly cooled. The precipitated product is filtered off with suction, washed with water and dried at 5CC in a vacuum drying cabinet.

Yield: 439.5 9 (92% of the theoretical value) Melting point: 790C - 7 IR spectrum: see Figure 2 'H-NMR spectrum: (CDC13) 6 = 3-3.2 (tr 2H, CH2- N); 6 3.6-3.8 (2Hr CH2-0); 6 = 3.8 (s, 3Hi 0CH3); 6 - 6.75-7.25 (m, 35, ArH)ppm. D. Preparation of 1-methoxy-2-amino4-(B-hydroxyethylamino)benzene sulphate:

159 g (0.75 mol) of the 1-methoxy-2-nitro-4-(8hydroxyethyl amino) benzene prepared in C. are tranferred together with 300 ml of methanol to a stainless steel autoclave, about 2 9 of Raney nickel are added, and the mixture is catalytically reduced at 700C over a period of five hours at a hydrogen pressure of 20 bar. After removal of the catalyst, 73,5 g of sulphuric acid are added to the filtrate. Once the batch is cooled the precipitated product is filtered off with suction, the residue is washed with a small amount of methanol and dried at about 5 VC in a vacuum drying cabinet.

Yield: 197 g (94% of the theoretical value) Melting point: 148-149'C IR Spectrum: see Figure 3 H-WX-R spectrum: (DMSO-dj 6 = 3.15-3.4 (t, 2H, CH2-N); 6 = 33-3.75 (2Hi CH2-O); 6 = 3.9 (si 3Hr O-CH3); 5 = 7.2-7.9 (m, 3H, Ar- H) ppm. Example 2 Preparation of 1-methoxy-2-aminc-4-(-y-hydroxypropyl- c-Lmino)benzene sulphate A. Preparation of 7-chloropropyl N-(3-nitro-4- methoxyphenyl) carbamate; 168.2 g (1 mol) of 1-methoxy-2 -nitro-4 -aminobenzene (prepared according to Example 1A) and 54 g of calcium carbonate are reacted in 570 ml of a mixture of monoethylene glycol dimethyl etherlwater (9:1) with 164 of 1chloropropyl chloroformate under the conditions mentioned in Exanple 1 B and the reaction mixture is worked up accordingly. Yield: 280 g (97% of the theoretical value) Melting point: 740C IR Spectr= see Figure 4 H-NHR spectrum: (CDC13) 6 13-2.15 (2HiC-CH2-C); 3.5-3.7 (tr 2H# CH2-0; 6 3.8 3H, O-CH3); 8 = 4.2-4.4 (t, 2R, -CH.2- Cl); 6 - 63-7.6 (m. 3H. Ar-H) ppm.

B. Preparationof 1-methoxy-2-nitro-4-(-y-hydroxypropyl amino)benzene:

216 9 (0.75 mol) of the -y-chloropropyl N-(3- nitro-4-methoxyphenyl) carbamate prepared above in A are reacted under the conditions mentioned in Example 1C with 2.50 g of 50% strength potassium hydroxide solution in 675 mI of water and 225 mI of ethanol. After the pH adjustments the product is extracted with ethyl acetate. Yield: 160 g of an oil (94% of the theoretical value) IR Spectrum; see Figure 5 'H-NMR spectrum: (CDC13) 8 = 1.7-2.0 (2H.. C-CH2-C) 3.1-3.3 (t, 2H, CH2-M; 5 = 3.6-3.8 (2H, CH2-0; 5 = 3.9 (s, 3H, O-Cl3) 6.7- 7.3 (m, 3H, Ar-H) ppm.

C. Preparationof 1-methoxy-2-a-mjno-4-(-f-hydroxypropyl- amino)benzene sulphate:

113 g (0.5 mol) of 1-methoxy- 2 -amino- 4 (-l -hy- droxypropylamino) benzene (prepared according to Example 2B) are hydrogenated under the conditions mentioned in Example 1D, the catalyst is separated off. 49 g of sulphuric acid are added to the filtrate and the product is isolated.

Yield: 140 g (95% of the theoretical value) Melting point: 166-168'C (with decomposition) IR Spectrum: see Figure 6 H-NHR spectrum: (DMSO-d,5).5 = 1.6-1.9 (2H, C-CH2-S); 6 = 3.1-3.3 (t, 2H, CH2-N); 5 = 3.4-3.6 (tl 2Hr CHz-0); 6 = 3.8 (st 3H, OCH3); 6.5-7.0 (mr 3H, Ar-H) ppm. Example 3 Preparation of 1-methoxy-2-amino4-(B-hydroxypropyl- amino)benzene sulphate A. Preparation of (2-chloro-i-methyl)ethyl N-(3-nitro4methoxyphenyl)carbamate:

16.8 g (0.1 mol) of 1-methoxy-2 -nitro-4 -amino- benzene (prepared according to Example IA) and 5.4 g of calcium carbonate are reacted in 55 ml of a mixture of monoethylene glycol dimethyl ether/water (9:1) under the conditions mentioned in Example 1B with 16.5 9 of (2chloro-i-methyl)ethyl chloroformate. and the product is worked up accordingly.

Yield: 28.5 g (99% of the theoretical value) Melting point: 72'C B. Preparation of 1-methoxy-2-nitro-4- (B-hydroxypropylamino)benzeno:

27.4 g (0.095 mol) of the (2 -chloro- 1 -methyl) ethyl N-(3-nitro-4methoxyphenyl)carbamate prepared according to Example 3A are reacted in 85 ml of water and 30 ml of ethanol under the conditions mentioned in Example 1C with 32.5 g of 50% strength potassium hydroxide solution. After the pH adjustment, the product is extracted with ethyl acetate.

Yield: 20 g of a red oil (93% of the theoretical value) C. Preparationof 1 -methoxy- 2 -amino- 4 - (13-hydroxypropylamino)benzene sulphate..

18.1 g (0.08 mol) of the 1-methoxy-2-nitro-4(13hydroxypropylamino)benzene prepared above in B are hydrogenated with 0. 3 9 of Raney nickel in 180 mI of methanol under the conditions mentioned in Example 1D, the catalyst is separated off from the reaction mixture, 7. 8 g of sulphuric acid are added to the filtrate, and af ter the removal of the solvent the product is isolated. Yield: 16 g (68% of the theoretical value).

The hair-dyeing compositions according to the invention, which contain the compounds according to Claim 2 as coupling components and developing substances used In general for oxidation-dyeing of hair,, are distinguished.by good stability on storage and upon application produce very deep shades reaching from red-brown to blueblack, and the dyeings obtained with them have good fastness properties.

When used in hair-dyeing compositions, the coupling component Is in general used in approximately molar amounts,. relative to the developing substances used. Although their use in molar amounts may be - advisable, it is, nevertheless. not a disadvantage if a certain excess or less than an equimolar amount of the coupling component is used.

The compounds according to Claim 2 to be used according to the invention as coupling components can be used either as such as or in the form of their salts with inorganic or organic acids, such as, for example, as chlorides, sulphates, phosphates, acetates, propionates. lactates, or citrates, The novel couplinq substances according to Claim 2 should be present in the hair-dyeing compositions according to the invention in a concentration of about 0.001 to 5.0% by weight and in particular 0.2 to 3. 0% by weight.

Furthermore it is not necessary that only one developing component be used; rather. a mixture of different developing compounds can also be used.

Examples of developing components to be used are primary aromatic or heteroaromatic amines having a further functional group in the p-position, such as pphenylenediamine, p-toluylenediamine, p-aminophenol,, N.. Ndimethyl-p-phenylenediamine, chloro-p-phenylenediamine, methoxy-pphenylenediamine 0 2. 5-diaminopyridine and their derivatives, and further compounds of the type mentioned which additionally contain one or more functional groups, such as OH groups, NH, groups, NHR groups or NRR groups in which R represents a substituted or unsubstituted alkyl radical having 1 to 4 carbon atoms.

Furthermore it is not necessary that only the coupling components of Claim 2 according to the invention be used; rather. to obtain certain shades, other already known and used coupling componentsi such as, for example, a-naphthol. 3,4-diaminobenzoic acid, resorcinol, 4- chlororesorcinol, m-aminophenol, m-phenylenediamine, mtoluylenediamine, 2, 4-diaminoanisol, catechol. pyrogallol, 1,5- or 1,7-dihydroxynaphthalene, 5-amino-2methylphenol, 6 -amino - 2 -methylphenol or derivatives of the compounds mentioned, for example 2f4-diaminophenyl tetrahydrofurfuryl ether according to German Patent 11. - Specification 31516,906 can also be used.

Moreover, the hair-dyeing compositions can, if desired, contain customary direct-dyeing dyes, if necessary for obtaining certain shades. The oxidative coupling, that is, the development of the dyeing, can in principle also, as in the case of other oxidation dyes, be carried out by means of atmospheric oxygen. However, advantageously chemical oxidizing agents are used.

The hair-dyeing compositions according to the invention are aqueous compositions. These are understood to mean any compositions which contain water in some fonn, such as, for example, creams, emulsions, gels or even simple solutions. The hair-dyeing compositions are composed of a mixture of dye components with additives customary for this type of cosmetic formulations.

Examples of suitable additives in solutions, creams, emulsions or gels are solvents, such as water, lower aliphatic alcohols, for example ethanol, propanol and isopropanol, or glycols, such as glycerol and glycol ethers, such as propylene glycolf furthermore wetting agents or emulsifiers from the class of anionic, cationic, amphoteric or nonionic surface-active substances, such as fatty alcohol sulphates, alkyl sulphonates, alkyl benzenesulphonates 1 a lkyltrimethyl Ammonium salts, alkyl betaines, oxethylated fatty alcohols, oxethylated nonylphenols, fatty acid alkanolamides, oxethylated fatty acid esters, furthermore thickening agents, such as higher fatty alcohols, starch, cellulose derivatives, Vaseline, paraffin oil and fatty acids.

The components mentioned are used in amounts customary for such purposes, for example the -wetting agent and emulsifiers in concentrations of about 0.5 to 30% by weight, whereas the thickening agents can be contained in the formulations in an amount of 0.1 to 25% by weight.

Depending on the composition, the hair-dyeing compositions according to the invention can be weakly acid, neutral or alkaline. In particular, they have a pH in the alkaline range between 7.5 and 11.5, which is 12 preferably adjusted with ammonia. However, it is also possible to use organic amines, for example monoethanolamine and triethanolamine, or even inorganic bases such as sodium hydroxide and potassium hydroxide.

In processes for the oxidative dyeing of hair, the hair-dyeing compositions of this invention,, which contain a combination of developing substances known in hair dyeing with at least one compound according to Claim 2 as coupling substance and also, if desired,, additionally known coupling substances and direct-dyeing dyes, are mixed shortly before use with an oxidizing agent and this mixture is applied to the hair. Suitable oxidizing agents for developing the hair dyeing are mainly hydrogen peroxide, for example a 6% strength aqueous solution and its addition compounds with urea, malamine or sodium borate and also mixtures consisting of this type of hydrogen peroxide addition compounds with potassium paroxodisulphate. The temperatures of this application are in the range from 15 to 400C. After a developing time of about 30 minutes, the hair-dyeing composition is removed from the hair to be dyed by rinsing. The hair is then washed again with a mild shampoo and dried.

The examples which follow are intended to illustrate the subject matter of the invention in more detail:

Example A Hair-dyeing composition in cream form 3.20 g of 1-methoxy-2-aminc-4-(7-hydroxypropylamino)benzene sulphate 1.95 g of p-phenylenediamine hydrochloride 0.10 g of m-aminophenol 2.00 g of oleic acid 0.10 g of polyacrylic acid 0.50 g of sodium sulphite, anhydrous 3.50 g of lauryl alcohol/diglycol ether sulphate, sodium salt (28% strength aqueous solution) i.

15.00 g of cetyl alcohol 73.65 9 of water 100.00 g 9 of the abovementioned hair-dyeing composition are mixed shortly before use with 50 g of hydrogen peroxide solutiont 6% strength. The mixture is allowed to act on light-brown natural hair at WC for 30 minutes. The dyeing material is then rinsed off,, the hair is whshed with shampoo and dried. it has obtained a full deep blue-black shade.

Example B Hair-dyeing composition in cream form 0.40 g of 1-methoxy-2-amino-4-(B-hydroxypropylamino)benzene sulphate 0.05 g of 1-methyl-2^hydroxy-4-aminobenzene 0.32 g of 2-chloro-p-phenylenediamine 2.00 g of clelc acid 0.10 g of polyaerylic acid 0.50 g of sodium sulphite, anhydrous 3.50 g of lauryl alcohol /diglycol ether sulphate, sodium salt (28% strength aqueous solution) 15.00 g of cetyl alcohol 79.13 q of water 100.00 9 g of the abovementioned hair-dyeing composition are mixed shortly before use with 50 g of hydrogen peroxide solution, 6% strength. The mixture is allowed to act on grey natural hair at 40C for 30 minutes. The dyeing material is then rinsed off,' the hair is washed with shampoo and dried. It has obtained a full deep lavender blue shade.

The accompanying drawings containing Figures 1 to 6 show the infra red absorption spectra of the following compounds:

Figure 1 B-chloroethyl N-(3-nitro-4-methoxyphenyl)carbamate; Figure 2 1-methoxy-2 -nitro-4 - (B-hydroxyethyl amino) benzene; 14 Figure 3 1-methoxy-2 -amino- 4 - (B-hydroxyethyl amino) - benzene sulphate; 2 Figure 4 y-chloropropyl N-(3-nitro-4-methoxyphenyl) carbanate; Figure 5 1-methoxy-2-nitro-4-(1-hydroxypropylamino)- benzene; Figure 6 1-methoxy-2amino-4-(,-hydroxypropylamino)- benzene sulphate CLAIMS:

A proces-s f or the preparation of N 4_substituted 1methoxy-2,,4-diaminobenzenes of general formula I OCH 3 NH-R in which R denotes a radical of general formula la -CR2-CR (A) -B (1a) and,f if A represents a hydrogen atom, B is a hydroxyl group or the HO-CH.-group; if A denotes a methyl group, B is a hydroxyl group; and their salts with inorganic and organic acids, wherein a) 4-methoxy-3-nitroacetanilide of formula 11 OCE 3 N 0 2 is converted to 4-methoxy-3-nitroaniline of formula 3 NO 2 NH by treatment with a strong inorganic acid in aqueous medium, b) the compound of formula III obtained is reacted with an equimolar amount of an allcyl chloro formate of general formula IV Cl-CGO-CH(X1)-CHz-Y1 (IV) - 16 In which X' Is a hydrogen atom and Y' is a chlorine atom or a Cl-CRa-group and# if X' denotes a methyl group, Y, represents a chlorine atom and C) the carbamate obtained of general formula v in which X, and Y' have the abovementioned meaning 0 C15 3 NO 2 1 (V) NH-COO-CII (2) -CH2-Y 1 is converted under basic conditions to a compound of general formula V1 OCE 3 NO 2 -:::5 (V1) NH-CH 2-CH(A)-B in which A and B have the meaning given f or f ormula la and d) the compound of general formula V1 is subjected to reduction and. if desired, e) the compound obtained of general formula 1 is converted to its salt by means of an inorganic or oroanic acid.

2. A compound of general formula I in which in general formula (1a), A denotes a methyl group and B a hydroxyl group or, it A is a hydrogen atom, B represents the HO-CH,-group.

3. A c,onipound of the general formula V1.

4. An aqueous- dyeing composition for keratin fibres, such as pelts and human hair, containing at least one compound according to Claim 2 as coupling agent and at least one developing component and also customary addi tives and auxiliaries.

5. A composition according to Claim 4 containing a 17 - compound according to claim 2 in an amount of 0.001 to 5 per cent by weight of the entire composition.

6. A composition according to claim 4 or 5 further containing a direct-dyeing dye.

7. A composition according to any one of claims 4 to 6, wherein the pH of the.composition is in the range from about 6.0 to 12.5.

:rom 8. - A composition according to claim 7, wherein the pH is 7.5 to 11.5.

9. A compound of general formula I in which in the general formula (Ia), A represents a hydrogen atom, B is a hydroxyl group or the HO-CH 2 -group; if A denotes a methyl group, B is a hydroxyl group; and its salts with inorganic and organic acids, prepared using a process according to claim 1.

10. An aqueous dyeing composition for keratin fibres, such as pelts and human hair, containing at least one compound according to claim 9 as coupling agent at at least one developing component and also customary additives and auxiliaries.

11. A process for the preparation of a compound according 11o claim 1, substantially as herein described.

12. A compound accordin. to claim 2 substantially as herein described.

13. A composition according to claim 4 substantially as herein described.

14. A compound according to claim 9 substantially as herein described.

15. A composition according to claim 10 substantially as herein described.

Published 1989 at The Patent Offtee, State House, 65"71 HIP Holborn, London WClR 4TF. Further copies maybe obtained from The P-atent Office'. Sales Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Multiplex techniques ltd, St Mary Cray, Kent, Cori. 1/87