Nicotinamide derivative or salt thereof as syk-inhibitors

Provided are compounds having excellent Syk-inhibitory activity and pharmaceutical compositions. Specifically provided are: nicotinamide derivatives represented by general formula (I) or salts thereof; and pharmaceutical compositions for the treatment of Syk-related diseases, which contain the nicotinamide derivatives or the salts thereof. In general formula (I), R1 is a halogen atom; R2 is C1-12 alkyl, C2-12 alkenyl, C2-12 alkynyl, C3-8 cycloalkyl, aryl, aralkyl (wherein the alkyl moiety has 1 to 6 carbon atoms), or a heterocyclic group, each being optionally substituted; R3 is aryl or a heterocyclic group, each being optionally substituted; R4 and R5 are each a hydrogen atom or the like; and R2 and R4 together with the nitrogen atom to which R2 and R4 are bonded may form an optionally substituted cyclic amino group.