The present invention relates to imidazo[1,2-a]
pyridazine derivatives, a preparation method thereof, a pharmaceutical composition and uses thereof. The present invention provides a compound represented by formula (1), its stereoisomers, tautomers, prodrugs, pharmaceutically acceptable salts, amorphous substances,
isotopomers, polymorphs or solvates. A pharmaceutical composition containing the compound and the use of the compound as a GABA A
receptor modulator, wherein R1, R2 and R3 are as defined in the specification.