A pharmaceutical
diluent and a compound of formula VI: wherein: R10=H, or C1-C20
alkyl, cycloalkyl, alkenyl,
aryl, arylalkyl, or alkylaryl, optionally containing
halogen atoms; R11=H3 or C]-C20
alkyl, cycloalkyl, alkenyl,
aryl, arylalkyl, or alkylaryl, optionally containing
halogen atoms; R12=H, or C1-C20
alkyl, cycloalkyl, alkenyl,
aryl, arylalkyl, or alkylaryl, optionally containing
halogen atoms, —C(O)R13, where R13 is H, Ci-C20 alkyl, cycloalkyl, alkenyl, aryl, arylalkyl, or alkylaryl, optionally containing halogen atoms, or —OH, —OR14 or —NR14, where R14 is H, C1-C20 alkyl, cycloalkyl, alkenyl, aryl, arylalkyl, or alkylaryl, optionally containing halogen atoms.