Verfahren zur Herstellung von Arylaminopyrazolen

摘要

The invention comprises arylamino pyrazoles of general formula wherein Ar2 is an unsubstituted or substituted aromatic nucleus containing the carboxyl group and pyrazolylamino group in positions adjacent to one another, R1 is an alkyl radical containing up to 4 carbon atoms or a phenyl radical, and R2 is an unsubstituted or substituted aliphatic, cycloaliphatic, aromatic-aliphatic, aromatic or heterocyclic radical which are prepared by reacting an oxazinone of formula in which Ar is an aromatic nucleus of which two adjacent carbon atoms form part of the oxazine ring, with one or two mols of hydrazine R2NH-NH2 per mol of oxazine, in the presence of an organic solvent at from 0 to 120 DEG C. The oxazinone may be prepared by dehydration of an o-carboxyarylamide of b -keto-carboxylic acid, in which Ar1 is an aromatic nucleus containing the carboxyl group and the acylamino group adjacent to each other which may in turn be prepared from diketones and aromatic o-aminocarboxylic acids. The reaction with the hydrazine may be carried out in water and hydrazine used in the form of a hydrochloride. Methyl, cyclohexyl, benzyl, phenyl hydrazines, phenyl hydrazine-sulphonic acids, nitrophenyl, chlorophenyl, alkylphenyl, a - and b -naphthyl and benzthiazolyl hydrazines are mentioned and the solvents may be alcohols, esters, ethers, aliphatic acids, and dimethyl formamide. Examples describe the preparation of numerous compounds and include the preparation of the oxazinone starting materials. The products may be used in the preparation of dyestuffs.ALSO:Arylamino pyrazoles of general formula wherein Ar2 is an unsubstituted or substituted aromatic nucleus containing the carboxyl group and pyrazolylamino group in positions adjacent to one another, R1 is an alkyl radical containing up to 4 carbon atoms or a phenyl radical, and R2 is an unsubstituted or substituted aliphatic, cycloaliphatic, aromatic-aliphatic, aromatic or heterocyclic radical (see Group IV(b)) are used to prepare azo-dyestuffs by coupling with diazonium compounds. In an example, an aqueous solution of 2-(41-sulphophenyl)-3 (211-carboxyphenylamino) - 5 - methyl - pyrazole is treated with diazonium chloride solution from 2-amino-5-nitro-anisole to give, after pptn. at pH 3, a brown powder which dyes wool in an acetic acid bath red-brown shades, changed to blue-green by alkali metal chromate treatment.