PYRIDOPYRIMIDINE OR NAPHTHYRIDINE DERIVATIVE

摘要

The present invention is directed to a pyridopyrimidine or a naphthyridine derivative of the formula (I): (see formula I) wherein R1 is an optionally substituted nitrogen-containing heterocyclic group, an optionally substituted amino group or an optionally substituted alkoxy group; R2 is a hydrogen atom or a lower alkyl group; R3 is a hydrogen atom, an optionally substituted lower alkyl group or an optionally substituted heteroaryl group; R4 is a hydrogen atom, a lower alkyl group, or an optionally esterified or amidated carboxyl group; R5 is a lower alkyl group which may be optionally substituted by a group selected from an optionally substituted aryl group, an optionally substituted heteroaryl group and a di-lower alkylamino group; and one of X and Y is a group of the formula: =CH- and the other is nitrogen atom, or X and Y are both nitrogen atoms, or a pharmaceutically acceptable salt thereof. These compounds exhibit excellent P DEV inhibitory activities, and are useful in the prophylaxis or treatment of penile erectile dysfunction and other functional disorders of cGMP-signaling.