6-Heterocyclic-imidazo[1,2-a]pyridine-2-carboxamide compounds (I) and their acid or base addition salts are new. 6-Heterocyclic-imidazo[1,2-a]pyridine-2-carboxamide compounds of formula (I) and their acid or base addition salts are new. X : phenyl (optionally substituted by 1-6C alkyl, 1-6C alkoxy (both optionally substituted by halo), halo, NR aR b, CN or 1-6C alkoxycarbonyl)； R 1 : 1-6C alkoxy, 1-6C alkyl (both optionally substituted by halo, OH, amino or 1-6C alkoxy), H, halo or NR aR b； R 2 : heterocyclic group (optionally substituted by OH, 1-6C alkoxy, halo, CN, NR aR b, -CO-R 5, -CO-NR 6R 7, -COOR 8, -NR 9-CO-R 10, 3-7C cycloalkyl-1-6C alkyl, 3-7C cycloalkyl-1-6C alkoxy, oxido or 1-6C alkyl optionally substituted by OH or NR aR b)； R 3 : H, 1-6C alkyl, 1-6C alkoxy or halo； R 4 : H, 1-4C alkyl, 1-4C alkoxy or F； R 5 : H, phenyl or 1-6C alkyl； either R 6, R 7 : H or 1-6C alkyl； or NR 6R 7 : 4-7 membered ring comprising optionally other heteroatoms of N, O or S； R 8 : 1-6C alkyl； R 9, R 10 : H or 1-6C alkyl； either R aR b : H or 1-6C alkyl； or NR aR b : 4-7 membered ring comprising optionally other heteroatoms of N, O or S. Provided that (I) excludes N-(4-bromophenyl)-6-(1-methyl-2-piperidinyl)imidazo[1,2-a]pyridine-2-carboxamide. An independent claim is included for 49 intermediate compounds (A) e.g. 6-bromo-N-phenylimidazo[1,2-a]pyridine-2-carboxamide, 6-iodo-N-phenylimidazo[1,2-a]pyridine-2-carboxamide, N-phenyl-6-cyano-imidazo[1,2-a]pyridine-2-carboxamide, 6-trimethylstannyl-N-phenylimidazo[1,2-a]pyridine-2-carboxamide, hydrobromide of N-phenyl-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-imidazo[1,2-a]pyridine-2-carboxamide, hydrochloride of 2-phenylcarbamoyl-imidazo[1,2-a]pyridine-6-boronic acid, N-phenyl-6-vinylimidazo[1,2-a]pyridine-2-carboxamide, 6-formyl-N-phenylimidazo[1,2-a]pyridine-2-carboxamide, 6-(2-bromo-acetyl)-N-phenyl-imidazo[1,2-a]pyridine-2-carboxamide, 6-(1-ethoxyvinyl)-N-pheylimidazo[1,2-a]pyridine-2-carboxamide, N-(3,5-difluorophenyl)-
