R10 is substituted or unsubstituted alkyl, ???C(O)-alkyl, ???C(O)???O-alkyl, alkoxy, cycloalkyl, alkenyl, or a substituted or unsubstituted, monocyclic or bicyclic aryl, heterocyclic or heteroaryl moiety containing from 1 to 6 heteroatoms; and R11 is a hydrogen or halogen atom.