Abstract: Compounds of the general formula (I) or a pharmaceutically acceptable salt, derivative, prodrug or stereoisomer therefor are provided: wherein the substituent groups defined by R are each independently selected from the group consisting of H, SiR?3, SOR?, SO2X, C(?O)R?, C(?O)OR?, C(?O)NR?, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, aryl, heteroaryl or aralkyl; the group R? is selected from substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, aminoalkyl, aryl, aralkyl and heterocyclic groups; and the group R? is selected from the group consisting of H, OH, OR?, OCOR?, SH, SR?, SOR?, SO2R?, NO2, NH2, NHR?, N(R?)2, NHCOR?, N(COR?)2, NHSO2R?, CN, halogen, C(?O)H, C(?O)R?, CO2H, CO2R?, CH2OR, substituted or unsubstituted alkyl, substituted or unsubstituted haloalkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkylidene, substituted or unsubstituted alkynyl, substi