A compound of formula wherein R 1 represents a heteroaromatic group selected from pyridinyl, benzodiazolyl and indolyl, the heteroaromatic group being substituted by one or two substituents independently selected from halogen, C 1 -C 3 alkyl and C 1 -C 2 haloalkyl; R 2 represents a hydrogen or fluorine atom or a hydroxyl or C 1 -C 3 alkoxy group; R 3 represents a hydrogen atom and R 4 represents a hydrogen atom; R 5 represents a heteroaromatic group selected from pyridinyl, pyridazinyl and pyrazolyl, the heteroaromatic group being substituted by at least one substituent selected from halogen, C 1 -C 2 alkyl and -NR 10 R 11; and R 10 and R 11 each independently represent a hydrogen atom or a C 1 -C 6 alkyl group; or a pharmaceutically acceptable salt thereof; provided that the compound of formula is not: 4-[3-(7-methyl-1H-1,3-benzodiazol-2-yl)piperidine-1-carbonyl]pyridin-2-amine, N-methyl-4-[3-(7-methyl-1H-1,3-benzodiazol-2-yl)piperidine-1-carbonyl]pyridin-2-amine, [3-(7-methyl-1H-benzimidazol-2-yl)-1-piperidinyl](1-methyl-1H-pyrazol-4-yl)methanone, (1-methyl-1H-pyrazol-4-yl)[3-(6-methyl-2-pyridinyl)-1-piperidinyl]methanone, [2-(methylamino)-4-pyridinyl] [3-[1-(1-methylethyl)-1H-benzimidazol-2-yl]-1-piperidinyl] methanone, (1,5-dimethyl-1H-pyrazol-4-yl)[3-(6-methyl-1H-benzimidazol-2-yl)-1-piperidinyl] methanone, (1-methyl-1H-pyrazol-4-yl)[3-(5-methyl-2-pyridinyl)-1-piperidinyl]methanone (CAS No. 1380857-90-8), or wherein R 1 represents a heteroaromatic group selected from pyridinyl, benzodiazolyl and indolyl, the heteroaromatic group being substituted by one or two substituents independently selected from halogen, C 1 -C 3 alkyl and C 1 -C 2 haloalkyl; R 2 represents a hydrogen or fluorine atom or a hydroxyl or C 1 -C 3 alkoxy group; R 3 represents a hydrogen atom and R 4 represents a hydrogen atom; R 5 represents a heteroaromatic group selected from pyridinyl, pyridazinyl and pyrazolyl, the heteroaromatic group being substituted by at least one substituent selected from halogen, C 1 -C 2 alkyl and -NR 10 R 11; and R 10 and R 11 each independently represent a hydrogen atom or a C 1 -C 6 alkyl group; R 1 represents a heteroaromatic group selected from pyridinyl, benzodiazolyl and indolyl, the heteroaromatic group being substituted by one or two substituents independently selected from halogen, C 1 -C 3 alkyl and C 1 -C 2 haloalkyl; R 2 represents a hydrogen or fluorine atom or a hydroxyl or C 1 -C 3 alkoxy group; R 3 represents a hydrogen atom and R 4 represents a hydrogen atom; R 5 represents a heteroaromatic group selected from pyridinyl, pyridazinyl and pyrazolyl, the heteroaromatic group being substituted by at least one substituent selected from halogen, C 1 -C 2 alkyl and -NR 10 R 11; and R 10 and R 11 each independently represent a hydrogen atom or a C 1 -C 6 alkyl group; or a pharmaceutically acceptable salt thereof; provided that the compound of formula is not: 4-[3-(7-methyl-1H-1,3-benzodiazol-2-yl)piperidine-1-carbonyl]pyridin-2-amine, N-methyl-4-[3-(7-methyl-1H-1,3-benzodiazol-2-yl)piperidine-1-carbonyl]pyridin-2-amine, [3-(7-methyl-1H-benzimidazol-2-yl)-1-piperidinyl](1-methyl-1H-pyrazol-4-yl)methanone, (1-methyl-1H-pyrazol-4-yl)[3-(6-methyl-2-pyridinyl)-1-piperidinyl]methanone, [2-(methylamino)-4-pyridinyl] [3-[1-(1-methylethyl)-1H-benzimidazol-2-yl]-1-piperidinyl] methanone, (1,5-dimethyl-1H-pyrazol-4-yl)[3-(6-methyl-1H-benzimidazol-2-yl)-1-piperidinyl] methanone, (1-methyl-1H-pyrazol-4-yl)[3-(5-methyl-2-pyridinyl)-1-piperidinyl]methanone (CAS No. 1380857-90-8), or 4-[3-(7-methyl-1H-1,3-benzodiazol-2-yl)piperidine-1-carbonyl]pyridin-2-amine, N-methyl-4-[3-(7-methyl-1H-1,3-benzodiazol-2-yl)piperidine-1-carbonyl]pyridin-2-amine, [3-(7-methyl-1H-benzimidazol-2-yl)-1-piperidinyl](1-methyl-1H-pyrazol-4-yl)methanone, (1-methyl-1H-pyrazol-4-yl)[3-(6-methyl-2-pyridinyl)-1-piperidinyl]methanone, [2-(methylamino)-4-pyridinyl] [3-[1-(1-methylethyl)-1H-benzimidazol-2-yl]-1-piperidinyl] methanone, (1,5-dimethyl-1H-pyrazol-4-yl)[3-(6-methyl-1H-benzimidazol-2-yl)-1-piperidinyl] methanone, (1-methyl-1H-pyrazol-4-yl)[3-(5-methyl-2-pyridinyl)-1-piperidinyl]methanone (CAS No. 1380857-90-8), or