Patent GB-666258-A (GB)
Title: Manufacture of new monoazo-dyestuffs of the pyrazolone series
Filed: 1949-02-11
Abstract: 2-Aminobenzoic acid -4- or -5-sulphonamides, free from further nuclear substituents but optionally having one or two hydrocarbon residues bound to the nitrogen atom, are manufactured by reacting a 2-chlorobenzoic acid-4-or -5-sulphonic acid chloride with ammonia or a primary or secondary amine, and replacing the nuclear chlorine atom by -NH2.  A list of compounds so obtainable is given.  2-Aminobenzoic acid-4-sulphonamide is also obtainable by heating a 1-nitro-2-methyl-benzene-5-sulphonamide in a medium containing an alkali hydroxide.  Pyrazolonesulphonamides of the general formula <FORM:0666258/IV (b)/1> wherein R represents an aromatic residue of the benzene series, which may contain further substituents such as halogen atoms (e.g. chlorine) or alkyl (e.g. methyl), alkoxy or nitro groups, and Z represents a sulphonamide group, which may contain one or two hydrocarbon residues bound to the nitrogen atom, are manufactured by reacting ethyl acetoacetate with an arylhydrazine containing a sulphonamide, preferably in the m-position.  A list of amines from which such arylhydrazines may be derived is given. Specification 302,965, [Class 2 (iii)], is referred to.ALSO:Monoazo dyestuffs are manufactured by coupling a diazo compound of an amine of the general formula <FORM:0666258/IV (c)/1> (wherein X is the sole further substituent in the nucleus and represents a sulphonamide group in p-position to one of the other substituents) with a pyrazolone having in the enol form the general formula <FORM:0666258/IV (c)/2> (wherein R represents an aromatic residue of the benzene series, which may contain further substituents, e.g. halogen atoms or alkyl, alkoxy or nitro groups, and Z represents a sulphonamide group), the components being so chosen that at least one of the two sulphonamide groups in the dyestuff molecule contains a hydrocarbon residue or residues bound to the nitrogen atom, that the hydrocarbon residue or residues of the sulphonamide groups contains or contain together at most 9 carbon atoms, and that the components contain no carboxylic or sulphonic acid groups apart from the single carboxyl group in the diazo component. Advantageously X is in p-position to the amino group and is of the form -SO2NHY (wherein Y represents a hydrocarbon residue of 3-6 carbon atoms, preferably a propyl or butyl radical), R is a m-phenylene group free from further substituents and Z is -SO2NH2.  Coupling is preferably conducted in an alkaline medium (e.g. by dissolving the pyrazolone with the necessary quantity of alkali hydroxide and adding excess alkali in the form of carbonate), and may if desired be effected in the presence of a neutral or basic solvent (e.g. alcohol, pyridine or ethanolamine).  The products may be used for dyeing or printing animal fibres (e.g. wool, silk or leather) and artificial fibres of superpolyamides or superpolyurethanes, giving yellow tints. They may be treated with agents yielding metal in substance, in the dyebath or on the fibre, especially by the single bath chroming process. Examples (1) to (3) describe the coupling of 1 - (31 - sulphonamido) - phenyl - 3 - methyl - 5-pyrazolone with diazotized 2-aminobenzene-1-carboxylic acid - 5 - sulphon - N - methyl-anilide, - n - butylamide and - anilide.  In further examples: (4) wool is dyed with the dyestuff 2 - aminobenzene - 1 - carboxylic acid-5 - sulphon - isopropylamide-->1 - (31 - sulphonamido) - phenyl - 3 - methyl - 5 - pyrazolone and after-chromed; (5) wool is dyed by the single bath chroming process with the corresponding n-butylamide. Lists of additional components are given.  Specification 302,965, [Class 2 (iv)], is referred to.