| abstract |
The invention relates to compounds represented by general formula (1) wherein R1 represents an alkyl group, R2 represents an amino group, alkyl group of the like, and R3 represents a nitro group, amino group, heterocyclic group, alkylsulfonylamino group or the like, or salts thereof, medicines comprising such a compound, a preparation process of the compounds, and intermediates useful for preparation thereof. The compounds (1) are useful for the prevention and treatment of a respiratory disease. |