| abstract |
The invention comprises 5-benzenesulphonamido-1-phenyl pyrazoles of the formula: <FORM:0865341/IV (b)/1> wherein Ar is a benzene ring optionally bearing a C1-2 alkyl or a C1-4 alkoxy substituent and in which the 3- and /or 4- position of the pyrazole ring may be substituted by a C1-2 alkyl radical, or the 3- and 4- positions may be co-condensed with a 5- or 6- membered cycloaliphatic ring, and alkali metal salts thereof; and their preparation by treating a 5-amino-1-phenyl pyrazole with a benzenesulphonyl halide in the presence of an acid acceptor such as an organic or inorganic base, e.g. a trialkylamine, pyridine, sodium carbonate or potassium carbonate, preferably in an inert solvent or diluent such as methylene chloride, diphenyl ether, diphenyl methane, paraffin oil, tetra- and decahydronaphthalene, methyl-naphthalene, chloronaphthalene or mixtures of these diluents. Suitably Ar may be a benzene, o, m or p-methylbenzene or p-methoxy-, propoxy- or butoxy-benzene residue and the 1-phenyl pyrazole ring is unsubstituted or bears a 3-methyl, 3:4-dimethyl, 3-methyl-4-ethyl, 3:4-trimethylene or 3:4-tetramethylene substituents. |