| abstract |
An object of the present invention is to provide a novel compound which has a strong inhibitory activity on protein tyrosine kinases, particularly Syk family tyrosine kinases, and is useful as a pharmaceutical. [Solution] General formula (I): Embedded image Wherein R 1 and R 2 are hydrogen, lower alkyl, optionally substituted phenyl or heteroaryl, and R 3 is hydrogen, lower alkyl, cycloalkyl, optionally substituted phenyl, heteroaryl or aralkyl And A is hydrogen, lower alkyl, cycloalkyl, R 4 , heteroaryl, OR 5 , SR 5 or NR 6 R 7 ]. [Selection diagram] None |