| abstract |
The compounds of the formula <IMAGE> I in which one of the groups R1, R2 and R3 represents hydrogen, C1-8-alkyl, C3-6-cycloalkyl, phenyl optionally substituted by halogeno, C1-4-alkyl, C1-4-alkoxy and/or trifluoromethyl, or C7-10-phenylalkyl optionally substituted in the phenyl moiety by halogeno, C1-4-alkyl, C1-4-alkoxy and/or trifluormethyl, and the other two are hydrogen, or salts thereof. These compounds have valuable pharmaceutical properties. |