| abstract |
The invention provides compounds of formula I: or pharmaceutically acceptable salts thereof, wherein R 1, R 2 and A, B and C rings are as defined herein. Compounds of formula I are useful in the treatment or prevention of cognitive disorders, such as Alzheimer's disease. The invention also encompasses pharmaceutical compositions which include compounds and salts of formula I, methods for preparing the desired compounds, and methods of treating cognitive disorders such as Alzheimer's disease, using the compounds or salts of formula I. |