8-Fluoroimidazo 1,2-a pyridine derivatives as ligands for gaba receptors

A compound of formula I, or a pharmaceutically acceptable salt thereof:

• wherein:
• Z represents an optionally substituted five-membered heteroaromatic ring selected from furan, thiophene, pyrrole, oxazole, thiazole, isoxazole, isothiazole, imidazole, pyrazole, oxadiazole, thiadiazole, triazole and tetrazole;
• or
• Z represents an optionally substituted six-membered heteroaromatic ring selected from pyridine, pyrazine, pyrimidine and pyridazine;
• R1 represents hydrogen, hydrocarbon, a heterocyclic group, halogen, cyano, trifluoromethyl, nitro, ORa, —SRa, —SORa, —SO2Ra, —SO2NRaRb, —NRaRb, —NRaCORb, —NRaCO2Rb, —CORa, —CO2Ra, —CONRaRb or —CRa═NORb;
• and
• Ra and Rb independently represent hydrogen, hydrocarbon or a heterocyclic group.

A compound which is selected from:

• 8-fluoro-3-(6-trifluoromethylpyridin-2-yl)imidazo[1,2-α]pyridine;
• 8-fluoro-3-(2-trifluoromethylpyrimidin-4-yl)imidazo[1,2-α]pyridine;
• 2-[8-fluoro-3-(2-trifluoromethylpyrimidin-4-yl)imidazo[1,2-α]pyridin-7-yl]propan-2-ol;
• 4-fluoro-2-{6-[8-fluoro-7-(1-hydroxy-1-methylethyl)imidazo[1,2-α]pyridin-3-yl]pyridin-2-yl}benzonitrile;
• 5-fluoro-2-{6-[8-fluoro-7-(1-hydroxy-1-methylethyl)imidazo[1,2-α]pyridin-3-yl]pyridin-2-yl}benzonitrile;
• 3-fluoro-2-{6-[8-fluoro-7-(1-hydroxy-1-methylethyl)imidazo[1,2-α]pyridin-3-yl]pyridin-2-yl}benzonitrile;
• or a pharmaceutically acceptable salt thereof.

A compound which is selected from:

• 2-{3-[2-(3,4-difluorophenyl)pyrimidin-4-yl]-8-fluoroimidazo[1,2-α]pyridin-7-yl}propan-2-ol;
• 2-{3-[2-(2,3-difluorophenyl)pyrimidin-4-yl]-8-fluoroimidazo[1,2-α]pyridin-7-yl}propan-2-ol;
• 2-{3-[2-(2,4-difluorophenyl)pyrimidin-4-yl]-8-fluoroimidazo[1,2-α]pyridin-7-yl}propan-2-ol;
• 2-{8-fluoro-3-[2-(3-fluorophenyl)pyrimidin-4-yl]imidazo[1,2-α]pyridin-7-yl}propan-2-ol;
• 2-{3-[2-(4-chloro-3-fluorophenyl)pyrimidin-4-yl]-8-fluoroimidazo[1,2-α]pyridin-7-yl}propan-2-ol;
• 2-{3-[2-(3-chloro-6-fluorophenyl)pyrimidin-4-yl]-8-fluoroimidazo[1,2-α]pyridin-7-yl}propan-2-ol;
• 2-{3-[2-(3-chloro-2-fluorophenyl)pyrimidin-4-yl]-8-fluoroimidazo[1,2-α]pyridin-7-yl}propan-2-ol;
• 2-{3-[2-(3-chloro-4-fluorophenyl)pyrimidin-4-yl]-8-fluoroimidazo[1,2-α]pyridin-7-yl}propan-2-ol;
• 2-{3-[2-(4-chlorophenyl)pyrimidin-4-yl]-8-fluoroimidazo[1,2-α]pyridin-7-yl}propan-2-ol;
• 2-{3-[2-(2,4-dichlorophenyl)pyrimidin-4-yl]-8-fluoroimidazo[1,2-α]pyridin-7-yl}propan-2-ol;
• 4-{4-[8-fluoro-7-(2-hydroxyprop-2-yl)imidazo[1,2-α]pyridin-3-yl]pyrimidin-2-yl}benzonitrile;
• 3-{4-[8-fluoro-7-(2-hydroxyprop-2-yl)imidazo[1,2-α]pyridin-3-yl]pyrimidin-2-yl}benzonitrile;
• 6-fluoro-3-{4-[8-fluoro-7-(2-hydroxyprop-2-yl)imidazo[1,2-α]pyridin-3-yl]pyrimidin-2-yl}benzonitrile;
• 2-fluoro-4-{4-[8-fluoro-7-(2-hydroxyprop-2-yl)imidazo[1,2-α]pyridin-3-yl]pyrimidin-2-yl}benzonitrile;
• 5-fluoro-2-{4-[8-fluoro-7-(2-hydroxyprop-2-yl)imidazo[1,2-α]pyridin-3-yl]pyrimidin-2-yl}benzonitrile;
• 5-fluoro-2-{4-[8-fluoro-7-(2-hydroxyprop-2-yl)imidazo[1,2-α]pyridin-3-yl]pyrimidin-2-yl}benzamide;
• 5-fluoro-2-{3-fluoro-6-[8-fluoro-7-(2-hydroxyprop-2-yl)imidazo[1,2-α]pyridin-3-yl]pyridin-2-yl}benzonitrile;
• 4-fluoro-2-{3-fluoro-6-[8-fluoro-7-(2-hydroxyprop-2-yl)imidazo[1,2-α]pyridin-3-yl]pyridin-2-yl}benzonitrile;
• 4-fluoro-2-{3-fluoro-4-[8-fluoro-7-(2-hydroxyprop-2-yl)imidazo[1,2-α]pyridin-3-yl]pyridin-2-yl}benzonitrile;
• 5-fluoro-2-{3-fluoro-4-[8-fluoro-7-(2-hydroxyprop-2-yl)imidazo[1,2-α]pyridin-3-yl]pyridin-2-yl}benzonitrile;
• 5-fluoro-2-{4-[8-fluoro-7-(2-hydroxyprop-2-yl)imidazo[1,2-α]pyridin-3-yl]pyridin-2-yl}benzonitrile;
• 2-{8-fluoro-3-[2-(3-fluorophenyl)pyridin-4-yl]imidazo[1,2-α]pyridin-7-yl}propan-2-ol;
• 3-fluoro-2-{4-[8-fluoro-7-(2-hydroxyprop-2-yl)imidazo[1,2-α]pyridin-3-yl]pyridin-2-yl}benzamide;
• 5-fluoro-2-{5-[8-fluoro-7-(2-hydroxyprop-2-yl)imidazo[1,2-α]pyridin-3-yl]pyridin-3-yl}benzonitrile;
• 5-fluoro-2-[3-fluoro-6-(8-fluoro-7-trifluoromethylimidazo[1,2-α]pyridin-3-yl)pyridin-2-yl]benzonitrile;
• 5-fluoro-2-[3-fluoro-4-(8-fluoro-7-trifluoromethylimidazo[1,2-α]pyridin-3-yl)pyridin-2-yl]benzonitrile;
• or a pharmaceutically acceptable salts thereof.