PYRIDOPYRIMIDIN-4-ONE DERIVATIVE

摘要

A compound represented by formula (I) (in the formula, X represents a nitrogen atom or the formula CH; R1 represents a C1-5 alkyl (this C1-5 alkyl may be substituted by 1-3 of the same or different substituents selected from hydroxy, halogen atoms, cyano, C3-7 cycloalkyl, and C1-5 alkoxy); and R2 represents a hydrogen atom or C1-5 alkyl (at least one hydrogen atom in this C1-5 alkyl is 3H)) or a pharmaceutically acceptable salt thereof is useful as a novel [3H]-labeled ligand that binds specifically to the arginine-vasopressin V1b receptors or as a precursor for efficient [3H]-labeled ligand synthesis.