FOERFARANDE FOER FRAMSTAELLNING AV NYA TERAPEUTISKT ANVAENDBARA 7-FENYL-, NAFTYL- OCH BENSOFURANYLISOTIAZOLO/4,5-D/-1,2,3-TRIAZIN-4(3H)-ONER

Compounds of the formula I wherein A represents a grouping of the formula (a) (b) (c) in which R1 and R2 each individually represent hydrogen, halogen, trifluoromethyl, nitro, amino, cyano, C1-C6-alkyl, C1-C6-alkoxy, C3-C6-alkenyloxy, C1-C6-alkylthio, C114 C6-alkanoylamino, aryloxy, aryl-(C1-C6-alkyl), aryl-(C1-C6-alkoxy), aryl-(C1-C6-alkoxy)carbonylamino or a group of the formula -O-CH2-R3 or R1 and R2 on adjacent carbon atoms together represent a group of the formula -CH=CH-CH=CH- or -CH2-CH2-O- and R3 represents hydroxy-(C1-C4-alkyl) or vicinal dihydroxy-(C2-C5-alkyl), and pharmaceutically acceptable acid addition salts of those compounds of formula I in which R1 and/or R2 represents amino, possess xanthine oxidase inhibiting activity and can be used as medicaments, particularly for the control or prevention of ischemia or gout. These compounds can be manufactured according to known methods.