| 摘要 |
The present invention provides, for example, a compound mentioned below as a medicament for treating or preventing the diseases induced by production, secretion or deposition of amyloid-&bgr; proteins. A compound of the formula (I): wherein R1, R2a, R2b, R3, R4a, R4b, ring A and the dashed lines are defined in the specification, its pharmaceutically acceptable salt or a solvate thereof. |
