A compound for treating a protein kinase-related disease or disorder having a structure of formula (I) wherein L is NR8 or O; R1, R2, R3, R4, R5, R6 and R7 are defined herein. Compounds of formula (I) are useful for inhibition of protein kinases. Methods of using compounds of formula (I), stereoisomers, tautomers and pharmaceutically acceptable salts thereof, for in vitro, in situ, and in vivo diagnosis, prevention or treatment of such disorders in mammalian cells, or associated pathological conditions are disclosed.