申请人:Santhakumar Vijayaratnam
                            
                            
                                公开号:US20070265325A1
                            
                            
                                公开(公告)日:2007-11-15
                            
                            Compounds of Formula I or pharmaceutically acceptable salts thereof.
wherein R
1
, R
2
, R
3
and R
4
are as defined in the specification as well as salts and pharmaceutical compositions including the compounds are prepared. They are useful in therapy, in particular in the management of pain.