A compound represented by general formula (I), or a salt thereof, having a Syk inhibitory effect. (In the formula, R1 represents a hydrogen atom or C1-C6 alkyl group optionally substituted by Ra A represents a hydrogen atom, C1-C8 alkyl group optionally substituted by Ra, C2-C6 alkenyl group optionally substituted by Ra, C2-C6 alkynyl group optionally substituted by Ra, C3-C10 cycloalkyl group optionally substituted by Rb, C6-C14 aromatic hydrocarbon group optionally substituted by Rb, 4- to 10-membered unsaturated heterocyclic group optionally substituted by Rb, or 4- to 10-membered saturated heterocyclic group optionally substituted by Rb, or R1 and the nitrogen atoms that link these may together form a 4- to 10-membered unsaturated heterocycle or a 4- to 10-membered saturated heterocycle R2 represents a hydrogen atom or C1-C6 alkyl group optionally substituted by Ra and B represents an unsaturated heterocyclic group optionally substituted by Rc.)本發明提供一種具有Syk抑制作用且具有細胞增殖抑制效果之新穎化合物。又,提供一種基於Syk抑制作用而對癌之預防及/或治療有用之醫藥。本發明提供下述通式(I)所表示之化合物或其鹽。(式中,R1表示氫原子或可經Ra取代之C1-C6烷基;A表示氫原子、可經Ra取代之C1-C8烷基、可經Ra取代之C2-C6烯基、可經Ra取代之C2-C6炔基、可經Rb取代之C3-C10環烷基、可經Rb取代之C6-C14芳香族烴基、可經Rb取代之4~10員之不飽和雜環基或可經Rb取代之4~10員之飽和雜環基,或者可與R1及該等所鍵結之氮原子共同形成4~10員之不飽和雜環或4~10員之飽和雜環;R2表示氫原子或可經Ra取代之C1-C6烷基;B表示可經Rc取代之不飽和雜環基。)
