Provided, for example, are a compound described below and the like, which have amyloid ß production inhibitory activity, especially BACE1 inhibitory effect and serve as therapeutic agents for diseases induced by the production, secretion and deposition of amyloid ß protein. A compound represented by formula (I), a pharmaceutically acceptable salt thereof, or a solvate of the compound or the salt. (In the formula, ring Z represents a substituted or unsubstituted pyridine or a substituted or unsubstituted carbon ring； ring A represents a substituted or unsubstituted carbon ring or a substituted or unsubstituted heterocyclic ring； R1 represents a substituted or unsubstituted alkyl or the like； and R2a, R2b, R4a and R4b each independently represents hydrogen, a substituted or unsubstituted alkyl or the like.)
