2-Aminopyridine compounds and use thereof as drugs

A pharmaceutical composition comprising a compound represented by the formula:

• 232
• (wherein R1 represents cyano group, carboxyl group or an optionally substituted carbamoyl group;
• R2 represents hydrogen atom, hydroxyl group, an optionally substituted C1-6 alkoxy group, an optionally substituted C6-14 aromatic hydrocarbon cyclic group or an optionally substituted 5- to 14-membered aromatic heterocyclic group;
• and R3 and R4 are the same as or different from each other and each represents a C3-8 cycloalkyl group, a C3-8 cycloalkenyl group, a C6-14 aromatic hydrocarbon cyclic group, a 5- to 14-membered non-aromatic heterocyclic group or a 5- to 14-membered aromatic heterocyclic group which may have a substituent group, respectively, provided that the cases where (1) R1 is cyano group, R2 is 4-bromo-2-thienyl group, R3 is 3,4-dimethoxyphenyl group and R4 is 2-thienyl group, (2) R1 is cyano group, R2 is hydrogen atom and each of R3 and R4 is phenyl group, (3) R1 is cyano group, R2 is 4-chloro-phenyl group, R3 is phenyl group and R4 is 4-(3,4-dichlorophenyl)-1-oxo-2(1H)-phthalazinyl group, (4) R1 is cyano group, R2 is hydrogen atom, R3 is 4-pyridyl group and R4 is 1-piperazinyl group, (5) R1 is cyano group, R2 is hydrogen atom, R3 is 4-pyridyl group and R4 is 1-pyridyl group, (6) R1 is cyano group, R2 is hydrogen atom, R3 is 4-pyridyl group and R4 is 4-diphenylmethyl-1-piperazinyl group, (7) R1 is cyano group, R2 is hydrogen atom, R3 is 4-pyridyl group and R4 is 4-morpholinyl group, (8) R1 is cyano group, R2 is 4-methylphenyl group and each of R3 and R4 is phenyl group, and (9) R1 is cyano group and each of R2, R3 and R4 is phenyl group are excluded) or a pharmacologically acceptable salt thereof and a pharmacologically acceptable carrier.