GB688225A - Improvements in or relating to the preparation of derivatives of 1:2:3-trisubstituted pyrazolones - Google Patents

Abstract

The invention comprises 1 : 2 : 3-trisubstituted pyrazolone derivatives of the general formula <FORM:0688225/IV (b)/1> (wherein R represents an alkyl or aryl radical, R1 an alkyl radical, R11 an unsubstituted or substituted aryl radical and -NHR111 the residue of a primary amine), and the manufacture thereof by reacting the correspondingly substituted pyrazolone-4-aldehydes with equimolecular proportions of a primary amine and sodium bisulphite, simultaneously or in either order. The products are therapeutically useful, having both antipyretic and bacteriostatic properties. In examples: (1) 1-phenyl-2 : 3 - dimethyl - 5 - pyrazolone - 4 - aldehyde is heated with aniline in the presence of potassium carbonate, and the resulting Schiff's base is reacted with sodium bisulphite in aqueous alcoholic solution; (2) 1 : 3-diphenyl-2-methyl-5-pyrazolone-4-aldehyde is similarly treated; (3) the Schiff's base from 1-p-ethoxyphenyl-2 : 3 - dimethyl - 5 - pyrazolone - 4 - aldehyde and p-ethoxyaniline is reacted with sodium bisulphite as in (1); (4) the p-ethoxyaniline in (3) is replaced by 4-amino-1-phenyl-2 : 3-dimethyl-5-pyrazolone; (5) and (6) the sodium bisulphite compound of 1-phenyl-2 : 3-dimethyl-5-pyrazolone-4-aldehyde is reacted with aniline; (7) 1-phenyl-2 : 3-dimethyl-5-pyrazolone-4-aldehyde is heated with p-aminobenzenesulphonamide and an aqueous solution of sodium bisulphite.