Decomposition inducer

The present invention provides a novel compound that induces the selective decomposition of non-receptor tyrosine kinases (especially tyrosine kinases that constitute the JAK family), or a pharmaceutically acceptable salt thereof. The present invention provides a compound represented by Formula I or a pharmaceutically acceptable salt thereof. The Formula I is as follows: (In the formula, R1 is a hydrogen atom or a C1-3 alkyl group optionally substituted with one or more deuterium atoms; R2 is CONHR3 (wherein R3 is a C1-3 alkyl group optionally substituted with one or more OH) or a triazole optionally substituted with one or more C1-3 alkyl groups; A is pyridyl or pyridazinyl; B is, or,; and n is an integer from 0 to 12.).