| abstract |
The invention provides novel compounds having the general formula: n n n n n n n n n n n n wherein X 1 is N or N + O − , and one of X 2 , X 3 and X 4 is N or N + —O − and the remainder of X 2 , X 3 and X 4 is C. R 2 , R 3 , R 4 , R 5 , R 6 . A, B and Y are as described herein. Additionally compositions compounds of Formula I and methods of use are further described herein. |