| abstract |
A compound having a structure of Formula I or a pharmaceutically acceptable salt thereof in which: ** Formula ** R1 is selected from H, -ZQZ, -C1-8-N alkyl (R2) (R4), -C1 alkyl -8-OR3, 3 to 8 membered carbocyclic or heterocyclic moiety, aryl, heteroaryl and C1-4 aralkyl; each R2 and R4 is independently selected for each occurrence from H, C1-4 alkyl, C1-4 aralkyl, aryl, heteroaryl, acyl, alkylsulfonyl and arylsulfonyl, with the proviso that when both R2 and R4 are on the same atom of N and none is H, these are different, and when both R2 and R4 are in the same Ny or R2 or R4 is acyl, alkylsulfonyl or arylsulfonyl, then the other is selected from H, C1-8 alkyl, aryl, C1-4 aralkyl and heteroaryl; R3 is selected from H, C1-4 alkyl, C1-4 aralkyl, aryl and heteroaryl; W is selected from: ** Formula ** |