Patent EP-0094038-B1 (EP)
IPC: A61K31/41
Filed: 1983-05-05
Granted: 1987-01-07
Abstract: 1. Claims for the Contracting States : BE, CH, DE, FR, GB, IT, LI, LU, NL, SE Amino-6-aryl-1,2,4-triazolo[4,3-b]pyridazines of the general formula I  see diagramm : EP0094038,P8,F2  and their salts with a physiologically tolerated acid, wherein R**1 and R**2 are identical or different and represent hydrogen, alkyl groups having 1-6 carbon atoms, phenyl or chlorine and Ar represents phenyl, biphenyl, phenoxyphenyl, phenylthiophenyl, phenylsulfinylphenyl, phenylsulfonylphenyl, 1- or 2-naphtyl, 2- or 3-thienyl, 2-furyl, 2-pyrrolyl, 1-methyl-2-pyrrolyl, 2-, 3- or 4-pyridyl, which radicals can optionally be substituted by one, two, three, four or five fluorine, chlorine, bromine, iodine, alkyl groups having 1-6 carbon atoms, cycloalkyl groups having 3-8 carbon atoms, phenylalkyl groups having 1-4 alkyl carbon atoms, alkoxy or alkylthio groups each having 1-6 carbon atoms, hydroxyl, nitro, cyano, trifluormethyl, carboxyl groups, their esters with C1 -C6 -alcohols, aminocarbonyl, amino, acetamino or alkoxycarbonylamino having 1-6 carbon atoms in the alkyl radical. 1. Claims for the Contracting State : AT Processes for the preparation of 3-amino-6-aryl-1,2,4-triazolo[4,3-b]pyridazines of the general formula I  see diagramm : EP0094038,P9,F1  and of their salts with a physiologically tolerated acid, wherein R**1 and R**2 are identical or different and represent hydrogen, alkyl groups having 1-6 carbon atoms, phenyl or chlorine and Ar represents phenyl, biphenyl, phenoxyphenyl, phenylthiophenyl, phenylsulfinylphenyl, phenylsulfonylphenyl, 1- or 2-naphtyl, 2- or 3-thienyl, 2-furyl, 2-pyrrolyl, 1-methyl-2-pyrrolyl, 2-, 3- or 4-pyridyl, which radicals can optionally be substituted by one, two, three, four or five fluorine, chlorine, bromine, iodine, alkyl groups having 1-6 carbon atoms, cycloalkyl groups having 3-8 carbon atoms, phenylalkyl groups having 1-4 alkyl carbon atoms, alkoxy or alkylthio groups each having 1-6 carbon atoms, hydroxyl, nitro, cyano, trifluormethyl, carboxyl groups, their esters with C1 -C6 -alcohols, aminocarbonyl, amino, acetamino or alkoxycarbonylamino having 1-6 carbon atoms in the alkyl radical which comprise a) reacting an arylhydrazinopyridazine of the formula II  see diagramm : EP0094038,P9,F4  wherein R**1 , R**2 and Ar have the meanings indicated for formula I, with cyanogen chloride, cyanogen bromide, O-methylisourea or S-methylisothiourea, guanidine or their salts, chloroformamidine hydrochloride or cyanamide as cyclization reagent, or b) reacting an arylhydrazinopyridazine of the formula II with a N-(R**3 -oxy)carbonyl-O-methylisourea, to give a compound of the formula III  see diagramm : EP0094038,P9,F6  wherein Ar, R**1 and R**2 have the meanings indicated for formula I and R**3 denotes alkyl having 1-10 carbon atoms, benzyl or phenyl, and then hydrolyzing the compound thus obtained, or c) reacting a compound of the formula IV  see diagramm : EP0094038,P9,F2  wherein R**4 denotes chlorine, bromine or methylthio, and Ar, R**1 and R**2 have the meanings indicated for formula I, with ammonia or d) cyclizing a compound of the formula V  see diagramm : EP0094038,P9,F3  wherein Ar, R**1 and R**2 have the meanings indicated for formula I and Z represents O, S or NH, by heating, optionally with the addition of a condensing agent, to give a compound of the formula I, and optionally converting the compound thus obtained into the salt with a physiologically tolerated acid.