Pyrazoles of formula (I), (where R3 is a residue -CX-Y-R4, -CX-Y-R4 or -CX-NR5 R6, in which R4 is H, 1-14C alkyl in which a methylene gp may be replaced by O, 3-6C cycloalkyl (alkyl or cycloalkyl opt. being substd. by a salt-forming basic gp), phenyl opt. substd. by 1-7C alkyl, 1-7 C alkoxy, 1-7 C alkylthio, 2-5 C alkoxycarbonyl, halogen, CF3, NO2 and/or CN, or (opt. substd. phenyl)-(1-6C alkyl); R5 and R6 are H, 1-7C alkyl in which a methylene gp. may be replaced by 0 or 3-6C cyclo-alkyl, or R5 + R6 is 2-5 C alkylene in which one or mor e methylene gps may be replaced by a hetero atom such as O or S or a group NR7, or R5 is H and R6 is an amino gp; X is S, NR7 or O; Y is O or S; and R7 is H or 1-7C alkyl) and their salts with acids (e.g. 1-propionyl-5-amino-4-formylcarbamoyl-pyrazole) may be prepd. by treating a cpd. of formula O=CH-NH-CO-C(CN)=CH-NH-NH-R3 (II) or its tautomer with an inert, O- or N-contg. organic solvent (pref. dioxan or ethanol), pref. at 20-150 degress C (esp. 60-120 degress C. (I) are cpds of low toxicity which inhibit the enzyme xanthine oxidase. When administered orally they give rise to a lowering of blood uric acid levels, and are therefor suitable for the treatment of gout. In addn., (I) are useful against coronary insufficiency and as antiarrhythmic agents.
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