The present invention provides a compound represented by the following general formula (I) or a salt thereof which has a
Syk inhibitory effect (in the formula R1 represents a
hydrogen atom or an optionally substituted C1-C6
alkyl group; A represents a
hydrogen atom, an optionally substituted C1-C8
alkyl group, an optionally substituted C2-C6 alkenyl group, an optionally substituted C2-C6 alkynyl group, an optionally substituted C3-C10 cycloalkyl group, an optionally substituted C6-C14
aromatic hydrocarbon group, an optionally substituted 4- to 10-membered unsaturated heterocyclic group, or an optionally substituted 4- to 10-membered saturated heterocyclic group, or optionally forms a 4- to 10-membered unsaturated heterocyclic ring or a 4- to 10-membered saturated heterocyclic ring together with R1 and the
nitrogen atom bonded thereto; R2 represents a
hydrogen atom or an optionally substituted C1-C6
alkyl group; and B represents an optionally substituted unsaturated heterocyclic group).