The compounds of Formula (I), in which R1, R21, R22, R23, R24, Y and R3 have the meanings as given in the description, the salts thereof, the N-oxides of the compounds and the salts thereof and the stereoisomers of the compounds, the salts, the N-oxides of the compounds and the N-oxides of the salts thereof are effective inhibitors of the type 5 phosphodiesterase.
