Tricyclic compound of the formula:
1
wherein ring A is a nitrogen-containing heterocyclic ring, having two nitrogen atoms as the hetero-atoms, which is optionally substituted with oxo or thioxo; ring Q may optionally be substituted;
Y is an optionally substituted hydrocarbon group, an optionally substituted hydroxyl group or an optionally substituted mecapto group, excluding for methyl group as Y; R
1
is a hydrogen atom, a halogen atom, an optionally substituted hydrocarbon group or an acyl group, or a salt thereof, having excellent PDGF-inhibiting activities, antihypertensive activities, activities of ameliorating renal diseases and activities of lowering lipid level.