Disclosed are compounds of formula (I), pharmaceutical compositions comprising such compounds and methods/uses of using the same, for example, for treating a JAK-related disorder, such as cancer, cancer cachexia or an immune disorder: wherein R1 is methyl or ethyl; R2 is selected from methyl, ethyl, methoxy and ethoxy; R3 is selected from hydrogen, chlorine, fluorine, bromine and methyl; R4 is selected from methyl, ethyl and —CH2OCH3; R5 and R6 are each individually methyl or hydrogen; and R7 is selected from methyl, ethyl, —(CH2)2OH and —(CH2)2OCH3, or a pharmaceutically acceptable salt thereof.