Abstract: 1,2,4-triazolo[4,3-b]pyridazine derivatives, possessing an optionally substituted cycloalkyl, phenyl or heteroaryl substituent as the 3-position and an amino moiety at the 6-position, are selective ligands for GABAA receptors, in particular having high affinity for the &agr;2 and/or &agr;3 subunit thereof, are useful in the treatment of anxiety and convulsions.

Abstract: This invention provides a compound of the following formula: and the pharmaceutically acceptable salts thereof, wherein L is oxygen or sulfur; Y is a direct bond or C1-4 alkylidene; Q is C1-6 alkyl, C3-7 cycloalkyl, phenyl, naphthyl, heteroaryl or the like; R1 is hydrogen, C1-6 alkyl or the like; R2 is hydrogen, C1-4 alkyl, C(O)R5 wherein R5 is C1-22 alkyl or C2-22 alkenyl, halosubstituted C1-8 alkyl, halosubstituted C2-8alkenyl, —Y—C3-7 cycloalkyl, —Y—C3-7 cycloalkenyl, phenyl, naphthyl, heteroaryl or the like; X is halo, C1-4 alkyl, hydroxy, C1-4 alkoxy or the like; and n is 0, 1, 2 or 3, with the proviso that a group of formula —Y—Q is not methyl or ethyl when X is hydrogen; L is oxygen; R1 is hydrogen; and R2 is acetyl. This invention also provides a pharmaceutical composition useful for the treatment of a medical condition in which prostaglandins are implicated as pathogens.