The compounds of formula (I) wherein R1, R21, R22, R23, R24, Y and R3 have the meanings as given in the description, the salts thereof, and the stereoisomers of the compounds and the salts thereof are effective inhibitors of the type 5 phosphodiesterase.
式(I)中的化合物,其中R1、R21、
R22、R23、R24、Y和R3的含义如描述中所示,其盐以及化合物和盐的立体异构体是有效的5型
磷酸二酯酶抑制剂。