摘要 |
The present invention provides a compound of the formula: a pharmaceutically acceptable salt or a prodrug thereof, where R<SUP>1</SUP>, R<SUP>2</SUP>, R<SUP>3</SUP>, R<SUP>4</SUP>, and n are those defined herein. The present invention also provides compositions comprising, methods for using, and methods for preparing Compound of Formula I. |