abstract |
The present invention is directed to a process for making Tetracyclic Heterocycle Compounds of Formula (I): n n n n n n n n n n and pharmaceutically acceptable salts thereof, wherein X 1 , X 2 , R 1 , R 2 and R 3 are defined above herein. The present invention is also directed to compounds that may be useful as synthetic intermediates in the process of the invention. |