or a salt thereof,

wherein

X represents a nitrogen atom or CH group;

Y represents a bond when X stands for nitrogen, or an oxygen atom or NH or CH₂ or OCH₂ group when X stands for CH group;

R₁, R₂, and R₃ may be the same or different and represent independently a substituent selected from hydrogen, halogen, C_1-6-alkyl, C_1-6 alkoxy, cyano, hydroxy, trifluoromethyl, C_1-6-alkylsulfonyloxy, trifluoromethanesulfonyloxy, C_1-6-alkanoyloxy, amino, alkylamino, alkanoylamino, alkylsulfonylamino, arylsulfonylamino, aminocarbonyl, carboxy, N-hydroxycarmamimidoyl, carbamimidoyl, hydroxycarbamoyl, thiocarbamoyl, sulfamoyl, mono or bicyclic heterocyclic group or optionally substituted phenyl, or two adjacent groups of R₁, R₂, and R₃ may combine to form an optionally substituted fused mono or bicyclic heterocyclic group; and

Q represents a dialkylamino group or an optionally substituted alkyl, aryl, heteroaryl, aralkyl or heteroaralkyl group

wherein “optionally substituted” means, independently at each use, optionally substituted with one or more substituents selected from the group consisting of halogen, cyano, trifluoromethyl, C_1-6-alkyl, C_1-6-alkoxy, C_1-6-alkanoyl, methylenedioxy, C_1-6-alkylamino, C_1-6-alkanoylamino, optionally substituted aroyl, aryloxy, aminosulfonyl, arylsulfonylamido, optionally substituted mono or bicyclic aromatic ring, and optionally substituted heteroaromatic ring.