| http://www.w3.org/ns/prov#value | - heteroatom selected from O, N or S, or X1 and X2 together comprise part of an imide ring having about 5 to about 6 members, X3 is selected from H, alkyl, hydroxyloweralkyl or alkyl-NX1X2, X4 is selected from H or alkyl; with the proviso that no R1 can be H when A is a direct bond and B is N; R2 is selected from a carbocyclic ring having about 4 to about 7 members, a heterocyclic ring having about
|
